pH/sommelier/sommelier.cc

// Copyright 2017 The ChromiumOS Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "sommelier.h"            // NOLINT(build/include_directory)
#include "sommelier-tracing.h"    // NOLINT(build/include_directory)
#include "sommelier-transform.h"  // NOLINT(build/include_directory)
#include "sommelier-xshape.h"     // NOLINT(build/include_directory)

#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <gbm.h>
#include <libgen.h>
#include <limits>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string>
#include <string.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>
#include <wayland-client.h>
#include <xcb/composite.h>
#include <xcb/shape.h>
#include <xcb/xcb.h>
#include <xcb/xfixes.h>
#include <xcb/xproto.h>

#include "aura-shell-client-protocol.h"  // NOLINT(build/include_directory)
#include "drm-server-protocol.h"         // NOLINT(build/include_directory)
#ifdef GAMEPAD_SUPPORT
#include "gaming-input-unstable-v2-client-protocol.h"  // NOLINT(build/include_directory)
#endif
#include "keyboard-extension-unstable-v1-client-protocol.h"  // NOLINT(build/include_directory)
#include "linux-dmabuf-unstable-v1-client-protocol.h"  // NOLINT(build/include_directory)
#include "linux-explicit-synchronization-unstable-v1-client-protocol.h"  // NOLINT(build/include_directory)
#include "pointer-constraints-unstable-v1-client-protocol.h"  // NOLINT(build/include_directory)
#include "relative-pointer-unstable-v1-client-protocol.h"  // NOLINT(build/include_directory)
#include "text-input-extension-unstable-v1-client-protocol.h"  // NOLINT(build/include_directory)
#include "text-input-unstable-v1-client-protocol.h"  // NOLINT(build/include_directory)
#include "viewporter-client-protocol.h"  // NOLINT(build/include_directory)
#include "xdg-output-unstable-v1-client-protocol.h"  // NOLINT(build/include_directory)
#include "xdg-shell-client-protocol.h"   // NOLINT(build/include_directory)

// Check that required macro definitions exist.
#ifndef XWAYLAND_PATH
#error XWAYLAND_PATH must be defined
#endif
#ifndef XWAYLAND_GL_DRIVER_PATH
#error XWAYLAND_GL_DRIVER_PATH must be defined
#endif
#ifndef FRAME_COLOR
#error FRAME_COLOR must be defined
#endif
#ifndef DARK_FRAME_COLOR
#error DARK_FRAME_COLOR must be defined
#endif

struct sl_data_source {
  struct sl_context* ctx;
  struct wl_data_source* internal;
};

#define SEND_EVENT_MASK 0x80

#define MIN_SCALE 0.1
#define MAX_SCALE 10.0

#define MIN_DPI 72
#define MAX_DPI 9600

#define XCURSOR_SIZE_BASE 24

#ifndef UNIX_PATH_MAX
#define UNIX_PATH_MAX 108
#endif

#define LOCK_SUFFIX ".lock"
#define LOCK_SUFFIXLEN 5

#define MIN_AURA_SHELL_VERSION 6
#define MAX_AURA_SHELL_VERSION 38

int sl_open_wayland_socket(const char* socket_name,
                           struct sockaddr_un* addr,
                           int* lock_fd,
                           int* sock_fd);

int sl_shm_format_for_drm_format(uint32_t drm_format) {
  switch (drm_format) {
    case WL_DRM_FORMAT_NV12:
      return WL_SHM_FORMAT_NV12;
    case WL_DRM_FORMAT_RGB565:
      return WL_SHM_FORMAT_RGB565;
    case WL_DRM_FORMAT_ARGB8888:
      return WL_SHM_FORMAT_ARGB8888;
    case WL_DRM_FORMAT_ABGR8888:
      return WL_SHM_FORMAT_ABGR8888;
    case WL_DRM_FORMAT_XRGB8888:
      return WL_SHM_FORMAT_XRGB8888;
    case WL_DRM_FORMAT_XBGR8888:
      return WL_SHM_FORMAT_XBGR8888;
  }
  assert(0);
  return 0;
}

uint32_t sl_drm_format_for_shm_format(int format) {
  switch (format) {
    case WL_SHM_FORMAT_NV12:
      return WL_DRM_FORMAT_NV12;
    case WL_SHM_FORMAT_RGB565:
      return WL_DRM_FORMAT_RGB565;
    case WL_SHM_FORMAT_ARGB8888:
      return WL_DRM_FORMAT_ARGB8888;
    case WL_SHM_FORMAT_ABGR8888:
      return WL_DRM_FORMAT_ABGR8888;
    case WL_SHM_FORMAT_XRGB8888:
      return WL_DRM_FORMAT_XRGB8888;
    case WL_SHM_FORMAT_XBGR8888:
      return WL_DRM_FORMAT_XBGR8888;
  }
  assert(0);
  return 0;
}

const char* net_wm_state_to_string(int i) {
  switch (i) {
    case NET_WM_STATE_REMOVE:
      return "NET_WM_STATE_REMOVE";
    case NET_WM_STATE_ADD:
      return "NET_WM_STATE_ADD";
    case NET_WM_STATE_TOGGLE:
      return "NET_WM_STATE_TOGGLE";
  }
  return "<unknown NET_WM_STATE>";
}

struct sl_sync_point* sl_sync_point_create(int fd) {
  TRACE_EVENT("sync", "sl_sync_point_create");
  struct sl_sync_point* sync_point = new sl_sync_point();
  sync_point->fd = fd;
  sync_point->sync = NULL;

  return sync_point;
}

void sl_sync_point_destroy(struct sl_sync_point* sync_point) {
  TRACE_EVENT("sync", "sl_sync_point_destroy");
  close(sync_point->fd);
  delete sync_point;
}

static void sl_internal_xdg_shell_ping(void* data,
                                       struct xdg_wm_base* xdg_shell,
                                       uint32_t serial) {
  TRACE_EVENT("shell", "sl_internal_xdg_shell_ping");
  xdg_wm_base_pong(xdg_shell, serial);
}

static const struct xdg_wm_base_listener sl_internal_xdg_shell_listener = {
    sl_internal_xdg_shell_ping};

static void sl_adjust_window_size_for_screen_size(struct sl_window* window) {
  TRACE_EVENT("surface", "sl_adjust_window_size_for_screen_size", "id",
              window->id);
  struct sl_context* ctx = window->ctx;

  // Clamp size to screen.
  window->width = MIN(window->width, ctx->screen->width_in_pixels);
  window->height = MIN(window->height, ctx->screen->height_in_pixels);
}

static void sl_adjust_window_position_for_screen_size(
    struct sl_window* window) {
  struct sl_context* ctx = window->ctx;

  // Center horizontally/vertically.
  window->x = ctx->screen->width_in_pixels / 2 - window->width / 2;
  window->y = ctx->screen->height_in_pixels / 2 - window->height / 2;
}

static void sl_set_input_focus(struct sl_context* ctx,
                               struct sl_window* window) {
  if (window) {
    xcb_client_message_event_t event;
    event.response_type = XCB_CLIENT_MESSAGE;
    event.format = 32;
    event.window = window->id;
    event.type = ctx->atoms[ATOM_WM_PROTOCOLS].value;
    event.data.data32[0] = ctx->atoms[ATOM_WM_TAKE_FOCUS].value;
    event.data.data32[1] = XCB_CURRENT_TIME;

    if (!window->managed)
      return;

    if (window->focus_model_take_focus) {
      xcb_send_event(ctx->connection, 0, window->id, XCB_EVENT_MASK_NO_EVENT,
                     reinterpret_cast<char*>(&event));
    }

    xcb_set_input_focus(ctx->connection, XCB_INPUT_FOCUS_NONE, window->id,
                        XCB_CURRENT_TIME);
  } else {
    xcb_set_input_focus(ctx->connection, XCB_INPUT_FOCUS_NONE, XCB_NONE,
                        XCB_CURRENT_TIME);
  }
}

void sl_restack_windows(struct sl_context* ctx, uint32_t focus_resource_id) {
  struct sl_window* sibling;
  uint32_t values[1];

  wl_list_for_each(sibling, &ctx->windows, link) {
    if (!sibling->managed)
      continue;

    // Move focus window to the top and all other windows to the bottom.
    values[0] = sibling->host_surface_id == focus_resource_id
                    ? XCB_STACK_MODE_ABOVE
                    : XCB_STACK_MODE_BELOW;
    xcb_configure_window(ctx->connection, sibling->frame_id,
                         XCB_CONFIG_WINDOW_STACK_MODE, values);
  }
}

void sl_roundtrip(struct sl_context* ctx) {
  TRACE_EVENT("other", "sl_roundtrip", "id",
              ctx->application_id != nullptr ? ctx->application_id : "<null>");
  free(xcb_get_input_focus_reply(ctx->connection,
                                 xcb_get_input_focus(ctx->connection), NULL));
}

static void sl_window_set_wm_state(struct sl_window* window, int state) {
  TRACE_EVENT("surface", "sl_window_set_wm_state", "id", window->id);
  struct sl_context* ctx = window->ctx;
  uint32_t values[2];

  values[0] = state;
  values[1] = XCB_WINDOW_NONE;

  xcb_change_property(ctx->connection, XCB_PROP_MODE_REPLACE, window->id,
                      ctx->atoms[ATOM_WM_STATE].value,
                      ctx->atoms[ATOM_WM_STATE].value, 32, 2, values);
}

static void sl_host_buffer_destroy(struct wl_client* client,
                                   struct wl_resource* resource) {
  TRACE_EVENT("surface", "sl_host_buffer_destroy");
  wl_resource_destroy(resource);
}

static const struct wl_buffer_interface sl_buffer_implementation = {
    sl_host_buffer_destroy};

static void sl_buffer_release(void* data, struct wl_buffer* buffer) {
  struct sl_host_buffer* host =
      static_cast<sl_host_buffer*>(wl_buffer_get_user_data(buffer));

  auto resource_id = host->resource ? wl_resource_get_id(host->resource) : -1;
  TRACE_EVENT("surface", "sl_buffer_release", "resource_id", resource_id);
  if (host->ctx->timing != NULL) {
    host->ctx->timing->UpdateLastRelease(resource_id);
  }
  wl_buffer_send_release(host->resource);
}

static const struct wl_buffer_listener sl_buffer_listener = {sl_buffer_release};

static void sl_destroy_host_buffer(struct wl_resource* resource) {
  TRACE_EVENT("surface", "sl_destroy_host_buffer", "resource_id",
              resource ? wl_resource_get_id(resource) : -1);
  struct sl_host_buffer* host =
      static_cast<sl_host_buffer*>(wl_resource_get_user_data(resource));

  if (host->proxy)
    wl_buffer_destroy(host->proxy);
  if (host->shm_mmap) {
    host->shm_mmap->buffer_resource = NULL;
    sl_mmap_unref(host->shm_mmap);
  }
  if (host->sync_point) {
    sl_sync_point_destroy(host->sync_point);
  }
  wl_resource_set_user_data(resource, NULL);
  delete host;
}

struct sl_host_buffer* sl_create_host_buffer(struct sl_context* ctx,
                                             struct wl_client* client,
                                             uint32_t id,
                                             struct wl_buffer* proxy,
                                             int32_t width,
                                             int32_t height,
                                             bool is_drm) {
  TRACE_EVENT("surface", "sl_create_host_buffer", "id", id);
  struct sl_host_buffer* host_buffer = new sl_host_buffer();

  host_buffer->ctx = ctx;
  host_buffer->width = width;
  host_buffer->height = height;
  host_buffer->resource =
      wl_resource_create(client, &wl_buffer_interface, 1, id);
  wl_resource_set_implementation(host_buffer->resource,
                                 &sl_buffer_implementation, host_buffer,
                                 sl_destroy_host_buffer);
  host_buffer->shm_mmap = NULL;
  host_buffer->shm_format = 0;
  host_buffer->proxy = proxy;
  if (host_buffer->proxy) {
    wl_buffer_add_listener(host_buffer->proxy, &sl_buffer_listener,
                           host_buffer);
  }
  host_buffer->sync_point = NULL;
  host_buffer->is_drm = is_drm;

  return host_buffer;
}  // NOLINT(whitespace/indent)

static void sl_internal_data_offer_destroy(struct sl_data_offer* host) {
  TRACE_EVENT("other", "sl_internal_data_offer_destroy");
  wl_data_offer_destroy(host->internal);
  wl_array_release(&host->atoms);
  wl_array_release(&host->cookies);
  delete host;
}

static void sl_set_selection(struct sl_context* ctx,
                             struct sl_data_offer* data_offer) {
  TRACE_EVENT("other", "sl_set_selection");
  if (ctx->selection_data_offer) {
    sl_internal_data_offer_destroy(ctx->selection_data_offer);
    ctx->selection_data_offer = NULL;
  }

  if (ctx->clipboard_manager) {
    if (!data_offer) {
      if (ctx->selection_owner == ctx->selection_window)
        xcb_set_selection_owner(ctx->connection, XCB_ATOM_NONE,
                                ctx->atoms[ATOM_CLIPBOARD].value,
                                ctx->selection_timestamp);
      return;
    }

    int atoms = data_offer->cookies.size / sizeof(xcb_intern_atom_cookie_t);
    wl_array_add(&data_offer->atoms, sizeof(xcb_atom_t) * (atoms + 2));
    (reinterpret_cast<xcb_atom_t*>(data_offer->atoms.data))[0] =
        ctx->atoms[ATOM_TARGETS].value;
    (reinterpret_cast<xcb_atom_t*>(data_offer->atoms.data))[1] =
        ctx->atoms[ATOM_TIMESTAMP].value;
    for (int i = 0; i < atoms; i++) {
      xcb_intern_atom_cookie_t cookie =
          (reinterpret_cast<xcb_intern_atom_cookie_t*>(
              data_offer->cookies.data))[i];
      xcb_intern_atom_reply_t* reply =
          xcb_intern_atom_reply(ctx->connection, cookie, NULL);
      if (reply) {
        (reinterpret_cast<xcb_atom_t*>(data_offer->atoms.data))[i + 2] =
            reply->atom;
        free(reply);
      }
    }

    xcb_set_selection_owner(ctx->connection, ctx->selection_window,
                            ctx->atoms[ATOM_CLIPBOARD].value, XCB_CURRENT_TIME);
  }

  ctx->selection_data_offer = data_offer;
}

static void sl_internal_data_offer_offer(void* data,
                                         struct wl_data_offer* data_offer,
                                         const char* type) {
  TRACE_EVENT("other", "sl_internal_data_offer_offer");
  struct sl_data_offer* host = static_cast<sl_data_offer*>(data);
  xcb_intern_atom_cookie_t* cookie = static_cast<xcb_intern_atom_cookie_t*>(
      wl_array_add(&host->cookies, sizeof(xcb_intern_atom_cookie_t)));
  *cookie = xcb_intern_atom(host->ctx->connection, 0, strlen(type), type);
}

static void sl_internal_data_offer_source_actions(
    void* data, struct wl_data_offer* data_offer, uint32_t source_actions) {
  TRACE_EVENT("other", "sl_internal_data_offer_source_actions");
}

static void sl_internal_data_offer_action(void* data,
                                          struct wl_data_offer* data_offer,
                                          uint32_t dnd_action) {
  TRACE_EVENT("other", "sl_internal_data_offer_action");
}

static const struct wl_data_offer_listener sl_internal_data_offer_listener = {
    sl_internal_data_offer_offer, sl_internal_data_offer_source_actions,
    sl_internal_data_offer_action};

static void sl_internal_data_device_data_offer(
    void* data,
    struct wl_data_device* data_device,
    struct wl_data_offer* data_offer) {
  struct sl_context* ctx = (struct sl_context*)data;
  struct sl_data_offer* host_data_offer = new sl_data_offer();

  host_data_offer->ctx = ctx;
  host_data_offer->internal = data_offer;
  wl_array_init(&host_data_offer->atoms);
  wl_array_init(&host_data_offer->cookies);

  wl_data_offer_add_listener(host_data_offer->internal,
                             &sl_internal_data_offer_listener, host_data_offer);
}

static void sl_internal_data_device_enter(void* data,
                                          struct wl_data_device* data_device,
                                          uint32_t serial,
                                          struct wl_surface* surface,
                                          wl_fixed_t x,
                                          wl_fixed_t y,
                                          struct wl_data_offer* data_offer) {}

static void sl_internal_data_device_leave(void* data,
                                          struct wl_data_device* data_device) {}

static void sl_internal_data_device_motion(void* data,
                                           struct wl_data_device* data_device,
                                           uint32_t time,
                                           wl_fixed_t x,
                                           wl_fixed_t y) {}

static void sl_internal_data_device_drop(void* data,
                                         struct wl_data_device* data_device) {}

static void sl_internal_data_device_selection(
    void* data,
    struct wl_data_device* data_device,
    struct wl_data_offer* data_offer) {
  struct sl_context* ctx = (struct sl_context*)data;
  struct sl_data_offer* host_data_offer =
      data_offer
          ? static_cast<sl_data_offer*>(wl_data_offer_get_user_data(data_offer))
          : NULL;

  sl_set_selection(ctx, host_data_offer);
}

static const struct wl_data_device_listener sl_internal_data_device_listener = {
    sl_internal_data_device_data_offer, sl_internal_data_device_enter,
    sl_internal_data_device_leave,      sl_internal_data_device_motion,
    sl_internal_data_device_drop,       sl_internal_data_device_selection};

void sl_host_seat_added(struct sl_host_seat* host) {
  struct sl_context* ctx = host->seat->ctx;

  if (ctx->default_seat)
    return;

  ctx->default_seat = host;

  // Get data device for selections.
  if (ctx->data_device_manager && ctx->data_device_manager->internal) {
    ctx->selection_data_device = wl_data_device_manager_get_data_device(
        ctx->data_device_manager->internal, host->proxy);
    wl_data_device_add_listener(ctx->selection_data_device,
                                &sl_internal_data_device_listener, ctx);
  }

#ifdef GAMEPAD_SUPPORT
  sl_gaming_seat_add_listener(ctx);
#endif
}

void sl_host_seat_removed(struct sl_host_seat* host) {
  TRACE_EVENT("other", "sl_host_seat_removed");
  if (host->seat->ctx->default_seat == host)
    host->seat->ctx->default_seat = NULL;
}

bool sl_client_supports_interface(const sl_context* ctx,
                                  const wl_client* client,
                                  const wl_interface* interface) {
  if (ctx->client == client) {
    return true;
  }
  // Clients created for IME support only receive the minimal set of required
  // interfaces.
  const char* name = interface->name;
  return strcmp(name, "wl_seat") == 0 ||
         strcmp(name, "zwp_text_input_manager_v1") == 0 ||
         strcmp(name, "zcr_text_input_extension_v1") == 0 ||
         strcmp(name, "zcr_text_input_x11_v1") == 0;
}

static void sl_global_destroy(struct sl_global* global) {
  TRACE_EVENT("other", "sl_global_destroy");
  struct sl_host_registry* registry;

  wl_list_for_each(registry, &global->ctx->registries, link) {
    if (sl_client_supports_interface(global->ctx,
                                     wl_resource_get_client(registry->resource),
                                     global->interface)) {
      wl_resource_post_event(registry->resource, WL_REGISTRY_GLOBAL_REMOVE,
                             global->name);
    }
  }

  wl_list_remove(&global->link);
  free(global);
}

// Called on each "wl_registry::global" event from the host compositor,
// giving Sommelier an opportunity to bind to the new global object
// (so we can receive events or invoke requests on it), and/or forward the
// wl_registry::global event on to our clients.
void sl_registry_handler(void* data,
                         struct wl_registry* registry,
                         uint32_t id,
                         const char* interface,
                         uint32_t version) {
  struct sl_context* ctx = (struct sl_context*)data;

  TRACE_EVENT("other", "sl_registry_handler", "id", id);
  if (strcmp(interface, "wl_compositor") == 0) {
    sl_compositor_init_context(ctx, registry, id, version);
  } else if (strcmp(interface, "wl_subcompositor") == 0) {
    struct sl_subcompositor* subcompositor =
        static_cast<sl_subcompositor*>(malloc(sizeof(struct sl_subcompositor)));
    assert(subcompositor);
    subcompositor->ctx = ctx;
    subcompositor->id = id;
    assert(!ctx->subcompositor);
    ctx->subcompositor = subcompositor;
    subcompositor->host_global = sl_subcompositor_global_create(ctx);
  } else if (strcmp(interface, "wl_shm") == 0) {
    struct sl_shm* shm = static_cast<sl_shm*>(malloc(sizeof(struct sl_shm)));
    assert(shm);
    shm->ctx = ctx;
    shm->id = id;
    shm->internal = static_cast<wl_shm*>(
        wl_registry_bind(registry, id, &wl_shm_interface, 1));
    assert(!ctx->shm);
    ctx->shm = shm;
    shm->host_global = sl_shm_global_create(ctx);
  } else if (strcmp(interface, "wl_shell") == 0) {
    struct sl_shell* shell =
        static_cast<sl_shell*>(malloc(sizeof(struct sl_shell)));
    assert(shell);
    shell->ctx = ctx;
    shell->id = id;
    assert(!ctx->shell);
    ctx->shell = shell;
    shell->host_global = sl_shell_global_create(ctx);
  } else if (strcmp(interface, "wl_output") == 0) {
    struct sl_output* output =
        static_cast<sl_output*>(malloc(sizeof(struct sl_output)));
    assert(output);
    output->ctx = ctx;
    output->id = id;
    output->version = MIN(3, version);
    output->host_global = sl_output_global_create(output);
    wl_list_insert(&ctx->outputs, &output->link);
    output->host_output = NULL;
  } else if (strcmp(interface, "wl_seat") == 0) {
    struct sl_seat* seat =
        static_cast<sl_seat*>(malloc(sizeof(struct sl_seat)));
    assert(seat);
    seat->ctx = ctx;
    seat->id = id;
    seat->version = MIN(5, version);
    seat->last_serial = 0;
    seat->host_global = sl_seat_global_create(seat);
    wl_list_insert(&ctx->seats, &seat->link);
  } else if (strcmp(interface, "zwp_relative_pointer_manager_v1") == 0) {
    struct sl_relative_pointer_manager* relative_pointer =
        static_cast<sl_relative_pointer_manager*>(
            malloc(sizeof(struct sl_relative_pointer_manager)));
    assert(relative_pointer);
    relative_pointer->ctx = ctx;
    relative_pointer->id = id;
    assert(!ctx->relative_pointer_manager);
    ctx->relative_pointer_manager = relative_pointer;
    relative_pointer->host_global =
        sl_relative_pointer_manager_global_create(ctx);
  } else if (strcmp(interface, "zwp_pointer_constraints_v1") == 0) {
    struct sl_pointer_constraints* pointer_constraints =
        static_cast<sl_pointer_constraints*>(
            malloc(sizeof(struct sl_pointer_constraints)));
    assert(pointer_constraints);
    pointer_constraints->ctx = ctx;
    pointer_constraints->id = id;
    assert(!ctx->pointer_constraints);
    ctx->pointer_constraints = pointer_constraints;
    pointer_constraints->host_global =
        sl_pointer_constraints_global_create(ctx);
  } else if (strcmp(interface, "wl_data_device_manager") == 0) {
    struct sl_data_device_manager* data_device_manager =
        static_cast<sl_data_device_manager*>(
            malloc(sizeof(struct sl_data_device_manager)));
    assert(data_device_manager);
    data_device_manager->ctx = ctx;
    data_device_manager->id = id;
    data_device_manager->version = MIN(3, version);
    data_device_manager->internal = NULL;
    data_device_manager->host_global = NULL;
    assert(!ctx->data_device_manager);
    ctx->data_device_manager = data_device_manager;
    if (ctx->xwayland) {
      data_device_manager->internal = static_cast<wl_data_device_manager*>(
          wl_registry_bind(registry, id, &wl_data_device_manager_interface,
                           data_device_manager->version));
    } else {
      data_device_manager->host_global =
          sl_data_device_manager_global_create(ctx);
    }
  } else if (strcmp(interface, "xdg_wm_base") == 0) {
    struct sl_xdg_shell* xdg_shell =
        static_cast<sl_xdg_shell*>(malloc(sizeof(struct sl_xdg_shell)));
    assert(xdg_shell);
    xdg_shell->ctx = ctx;
    xdg_shell->id = id;
    xdg_shell->internal = NULL;
    xdg_shell->host_global = NULL;
    assert(!ctx->xdg_shell);
    ctx->xdg_shell = xdg_shell;
    if (ctx->xwayland) {
      xdg_shell->internal = static_cast<xdg_wm_base*>(
          wl_registry_bind(registry, id, &xdg_wm_base_interface, 1));
      xdg_wm_base_add_listener(xdg_shell->internal,
                               &sl_internal_xdg_shell_listener, NULL);
    } else {
      xdg_shell->host_global = sl_xdg_shell_global_create(ctx);
    }
  } else if (strcmp(interface, "zaura_shell") == 0) {
    if (version >= MIN_AURA_SHELL_VERSION) {
      struct sl_aura_shell* aura_shell =
          static_cast<sl_aura_shell*>(malloc(sizeof(struct sl_aura_shell)));
      assert(aura_shell);
      aura_shell->ctx = ctx;
      aura_shell->id = id;
      aura_shell->version = MIN(MAX_AURA_SHELL_VERSION, version);
      aura_shell->host_gtk_shell_global = NULL;
      aura_shell->internal = static_cast<zaura_shell*>(wl_registry_bind(
          registry, id, &zaura_shell_interface, aura_shell->version));
      assert(!ctx->aura_shell);
      ctx->aura_shell = aura_shell;
      aura_shell->host_gtk_shell_global = sl_gtk_shell_global_create(ctx);
    }
  } else if (strcmp(interface, "wp_viewporter") == 0) {
    struct sl_viewporter* viewporter =
        static_cast<sl_viewporter*>(malloc(sizeof(struct sl_viewporter)));
    assert(viewporter);
    viewporter->ctx = ctx;
    viewporter->id = id;
    viewporter->host_viewporter_global = NULL;
    viewporter->internal = static_cast<wp_viewporter*>(
        wl_registry_bind(registry, id, &wp_viewporter_interface, 1));
    assert(!ctx->viewporter);
    ctx->viewporter = viewporter;
    viewporter->host_viewporter_global = sl_viewporter_global_create(ctx);
    // Allow non-integer scale.
    ctx->scale = MIN(MAX_SCALE, MAX(MIN_SCALE, ctx->desired_scale));
  } else if (strcmp(interface, "zwp_linux_dmabuf_v1") == 0) {
    struct sl_linux_dmabuf* linux_dmabuf =
        static_cast<sl_linux_dmabuf*>(malloc(sizeof(struct sl_linux_dmabuf)));
    assert(linux_dmabuf);
    linux_dmabuf->ctx = ctx;
    linux_dmabuf->id = id;
    linux_dmabuf->version = MIN(2, version);
    linux_dmabuf->internal = static_cast<zwp_linux_dmabuf_v1*>(wl_registry_bind(
        registry, id, &zwp_linux_dmabuf_v1_interface, linux_dmabuf->version));
    assert(!ctx->linux_dmabuf);
    ctx->linux_dmabuf = linux_dmabuf;
    linux_dmabuf->host_drm_global = sl_drm_global_create(ctx);
  } else if (strcmp(interface, "zwp_linux_explicit_synchronization_v1") == 0) {
    struct sl_linux_explicit_synchronization* linux_explicit_synchronization =
        static_cast<sl_linux_explicit_synchronization*>(
            malloc(sizeof(struct sl_linux_explicit_synchronization)));
    assert(linux_explicit_synchronization);
    linux_explicit_synchronization->ctx = ctx;
    linux_explicit_synchronization->id = id;
    linux_explicit_synchronization->internal =
        static_cast<zwp_linux_explicit_synchronization_v1*>(wl_registry_bind(
            registry, id, &zwp_linux_explicit_synchronization_v1_interface, 1));
    assert(!ctx->linux_explicit_synchronization);
    ctx->linux_explicit_synchronization = linux_explicit_synchronization;
  } else if (strcmp(interface, "zcr_keyboard_extension_v1") == 0) {
    struct sl_keyboard_extension* keyboard_extension =
        static_cast<sl_keyboard_extension*>(
            malloc(sizeof(struct sl_keyboard_extension)));
    assert(keyboard_extension);
    keyboard_extension->ctx = ctx;
    keyboard_extension->id = id;
    keyboard_extension->internal =
        static_cast<zcr_keyboard_extension_v1*>(wl_registry_bind(
            registry, id, &zcr_keyboard_extension_v1_interface, 1));
    assert(!ctx->keyboard_extension);
    ctx->keyboard_extension = keyboard_extension;
  } else if (strcmp(interface, "zwp_text_input_manager_v1") == 0) {
    struct sl_text_input_manager* text_input_manager =
        static_cast<sl_text_input_manager*>(
            malloc(sizeof(struct sl_text_input_manager)));
    assert(text_input_manager);
    text_input_manager->ctx = ctx;
    text_input_manager->id = id;
    text_input_manager->host_global = sl_text_input_manager_global_create(ctx);
    text_input_manager->host_x11_global = sl_text_input_x11_global_create(ctx);
    assert(!ctx->text_input_manager);
    ctx->text_input_manager = text_input_manager;
  } else if (strcmp(interface, "zcr_text_input_extension_v1") == 0) {
    struct sl_text_input_extension* text_input_extension =
        static_cast<sl_text_input_extension*>(
            malloc(sizeof(struct sl_text_input_extension)));
    assert(text_input_extension);
    text_input_extension->ctx = ctx;
    text_input_extension->id = id;
    text_input_extension->host_global =
        sl_text_input_extension_global_create(ctx);
    assert(!ctx->text_input_extension);
    ctx->text_input_extension = text_input_extension;
#ifdef GAMEPAD_SUPPORT
  } else if (strcmp(interface, "zcr_gaming_input_v2") == 0) {
    struct sl_gaming_input_manager* gaming_input_manager =
        static_cast<sl_gaming_input_manager*>(
            malloc(sizeof(struct sl_gaming_input_manager)));
    assert(gaming_input_manager);
    gaming_input_manager->ctx = ctx;
    gaming_input_manager->id = id;
    gaming_input_manager->internal = static_cast<zcr_gaming_input_v2*>(
        wl_registry_bind(registry, id, &zcr_gaming_input_v2_interface, 2));
    assert(!ctx->gaming_input_manager);
    ctx->gaming_input_manager = gaming_input_manager;
#endif
  } else if (strcmp(interface, "zxdg_output_manager_v1") == 0 &&
             ctx->use_direct_scale) {
    // This protocol cannot be bound unconditionally as doing so
    // causes issues under Crostini. For this reason we will only
    // bind it when we need to do so (direct mode enabled).

    struct sl_xdg_output_manager* output_manager =
        static_cast<sl_xdg_output_manager*>(
            malloc(sizeof(struct sl_xdg_output_manager)));
    assert(output_manager);

    output_manager->ctx = ctx;
    output_manager->id = id;
    output_manager->internal =
        static_cast<zxdg_output_manager_v1*>(wl_registry_bind(
            registry, id, &zxdg_output_manager_v1_interface, MIN(3, version)));
    ctx->xdg_output_manager = output_manager;
  }
}

static void sl_registry_remover(void* data,
                                struct wl_registry* registry,
                                uint32_t id) {
  TRACE_EVENT("other", "sl_registry_remover");
  struct sl_context* ctx = (struct sl_context*)data;
  struct sl_output* output;
  struct sl_seat* seat;

  if (ctx->compositor && ctx->compositor->id == id) {
    sl_global_destroy(ctx->compositor->host_global);
    wl_compositor_destroy(ctx->compositor->internal);
    free(ctx->compositor);
    ctx->compositor = NULL;
    return;
  }
  if (ctx->subcompositor && ctx->subcompositor->id == id) {
    sl_global_destroy(ctx->subcompositor->host_global);
    wl_shm_destroy(ctx->shm->internal);
    free(ctx->subcompositor);
    ctx->subcompositor = NULL;
    return;
  }
  if (ctx->shm && ctx->shm->id == id) {
    sl_global_destroy(ctx->shm->host_global);
    free(ctx->shm);
    ctx->shm = NULL;
    return;
  }
  if (ctx->shell && ctx->shell->id == id) {
    sl_global_destroy(ctx->shell->host_global);
    free(ctx->shell);
    ctx->shell = NULL;
    return;
  }
  if (ctx->data_device_manager && ctx->data_device_manager->id == id) {
    if (ctx->data_device_manager->host_global)
      sl_global_destroy(ctx->data_device_manager->host_global);
    if (ctx->data_device_manager->internal)
      wl_data_device_manager_destroy(ctx->data_device_manager->internal);
    free(ctx->data_device_manager);
    ctx->data_device_manager = NULL;
    return;
  }
  if (ctx->xdg_shell && ctx->xdg_shell->id == id) {
    if (ctx->xdg_shell->host_global)
      sl_global_destroy(ctx->xdg_shell->host_global);
    if (ctx->xdg_shell->internal)
      xdg_wm_base_destroy(ctx->xdg_shell->internal);
    free(ctx->xdg_shell);
    ctx->xdg_shell = NULL;
    return;
  }
  if (ctx->aura_shell && ctx->aura_shell->id == id) {
    if (ctx->aura_shell->host_gtk_shell_global)
      sl_global_destroy(ctx->aura_shell->host_gtk_shell_global);
    zaura_shell_destroy(ctx->aura_shell->internal);
    free(ctx->aura_shell);
    ctx->aura_shell = NULL;
    return;
  }
  if (ctx->viewporter && ctx->viewporter->id == id) {
    if (ctx->viewporter->host_viewporter_global)
      sl_global_destroy(ctx->viewporter->host_viewporter_global);
    wp_viewporter_destroy(ctx->viewporter->internal);
    free(ctx->viewporter);
    ctx->viewporter = NULL;
    return;
  }
  if (ctx->linux_dmabuf && ctx->linux_dmabuf->id == id) {
    if (ctx->linux_dmabuf->host_drm_global)
      sl_global_destroy(ctx->linux_dmabuf->host_drm_global);
    zwp_linux_dmabuf_v1_destroy(ctx->linux_dmabuf->internal);
    free(ctx->linux_dmabuf);
    ctx->linux_dmabuf = NULL;
    return;
  }
  if (ctx->linux_explicit_synchronization &&
      ctx->linux_explicit_synchronization->id == id) {
    zwp_linux_explicit_synchronization_v1_destroy(
        ctx->linux_explicit_synchronization->internal);
    free(ctx->linux_explicit_synchronization);
    ctx->linux_explicit_synchronization = NULL;
    return;
  }
  if (ctx->keyboard_extension && ctx->keyboard_extension->id == id) {
    zcr_keyboard_extension_v1_destroy(ctx->keyboard_extension->internal);
    free(ctx->keyboard_extension);
    ctx->keyboard_extension = NULL;
    return;
  }
  if (ctx->text_input_manager && ctx->text_input_manager->id == id) {
    sl_global_destroy(ctx->text_input_manager->host_global);
    free(ctx->text_input_manager);
    ctx->text_input_manager = NULL;
    return;
  }
  if (ctx->text_input_extension && ctx->text_input_extension->id == id) {
    sl_global_destroy(ctx->text_input_extension->host_global);
    free(ctx->text_input_extension);
    ctx->text_input_extension = NULL;
    return;
  }
#ifdef GAMEPAD_SUPPORT
  if (ctx->gaming_input_manager && ctx->gaming_input_manager->id == id) {
    zcr_gaming_input_v2_destroy(ctx->gaming_input_manager->internal);
    free(ctx->gaming_input_manager);
    ctx->gaming_input_manager = NULL;
    return;
  }
#endif
  if (ctx->relative_pointer_manager &&
      ctx->relative_pointer_manager->id == id) {
    sl_global_destroy(ctx->relative_pointer_manager->host_global);
    free(ctx->relative_pointer_manager);
    ctx->relative_pointer_manager = NULL;
    return;
  }
  if (ctx->pointer_constraints && ctx->pointer_constraints->id == id) {
    sl_global_destroy(ctx->pointer_constraints->host_global);
    free(ctx->pointer_constraints);
    ctx->pointer_constraints = NULL;
    return;
  }
  wl_list_for_each(output, &ctx->outputs, link) {
    if (output->id == id) {
      sl_global_destroy(output->host_global);
      if (output->host_output)
        wl_resource_destroy(output->host_output->resource);
      wl_list_remove(&output->link);
      free(output);
      return;
    }
  }
  wl_list_for_each(seat, &ctx->seats, link) {
    if (seat->id == id) {
      sl_global_destroy(seat->host_global);
      wl_list_remove(&seat->link);
      free(seat);
      return;
    }
  }

  // Not reached.
  assert(0);
}

const struct wl_registry_listener sl_registry_listener = {sl_registry_handler,
                                                          sl_registry_remover};

static int sl_handle_event(int fd, uint32_t mask, void* data) {
  TRACE_EVENT("other", "sl_handle_event");
  struct sl_context* ctx = (struct sl_context*)data;
  int count = 0;

  if ((mask & WL_EVENT_HANGUP) || (mask & WL_EVENT_ERROR)) {
    wl_client_flush(ctx->client);
    exit(EXIT_SUCCESS);
  }

  if (mask & WL_EVENT_READABLE)
    count = wl_display_dispatch(ctx->display);
  if (mask & WL_EVENT_WRITABLE)
    wl_display_flush(ctx->display);

  if (mask == 0) {
    count = wl_display_dispatch_pending(ctx->display);
    wl_display_flush(ctx->display);
  }

  return count;
}

void sl_create_window(struct sl_context* ctx,
                      xcb_window_t id,
                      int x,
                      int y,
                      int width,
                      int height,
                      int border_width) {
  TRACE_EVENT("surface", "sl_create_window");
  sl_window* window = new sl_window(ctx, id, x, y, width, height, border_width);
  uint32_t values[1];
  values[0] = XCB_EVENT_MASK_PROPERTY_CHANGE | XCB_EVENT_MASK_FOCUS_CHANGE;
  xcb_change_window_attributes(ctx->connection, window->id, XCB_CW_EVENT_MASK,
                               values);

  // Also enable shape events for this window to come in if the xshape
  // flag has been enabled
  if (ctx->enable_xshape)
    xcb_shape_select_input(ctx->connection, id, 1);
}

static void sl_destroy_window(struct sl_window* window) {
  TRACE_EVENT("surface", "sl_destroy_window");
  if (window->frame_id != XCB_WINDOW_NONE)
    xcb_destroy_window(window->ctx->connection, window->frame_id);

  if (window->xdg_popup)
    xdg_popup_destroy(window->xdg_popup);
  if (window->xdg_toplevel)
    xdg_toplevel_destroy(window->xdg_toplevel);
  if (window->xdg_surface)
    xdg_surface_destroy(window->xdg_surface);
  if (window->aura_surface)
    zaura_surface_destroy(window->aura_surface);

  delete window;
}

static int sl_is_window(struct sl_window* window, xcb_window_t id) {
  if (window->id == id)
    return 1;

  if (window->frame_id != XCB_WINDOW_NONE) {
    if (window->frame_id == id)
      return 1;
  }

  return 0;
}

struct sl_window* sl_lookup_window(struct sl_context* ctx, xcb_window_t id) {
  struct sl_window* window;

  wl_list_for_each(window, &ctx->windows, link) {
    if (sl_is_window(window, id))
      return window;
  }
  wl_list_for_each(window, &ctx->unpaired_windows, link) {
    if (sl_is_window(window, id))
      return window;
  }
  return NULL;
}

int sl_is_our_window(struct sl_context* ctx, xcb_window_t id) {
  const xcb_setup_t* setup = xcb_get_setup(ctx->connection);

  return (id & ~setup->resource_id_mask) == setup->resource_id_base;
}

static void sl_handle_create_notify(struct sl_context* ctx,
                                    xcb_create_notify_event_t* event) {
  if (sl_is_our_window(ctx, event->window))
    return;

  sl_create_window(ctx, event->window, event->x, event->y, event->width,
                   event->height, event->border_width);
}

void sl_handle_destroy_notify(struct sl_context* ctx,
                              xcb_destroy_notify_event_t* event) {
  struct sl_window* window;

  if (sl_is_our_window(ctx, event->window))
    return;

  window = sl_lookup_window(ctx, event->window);
  if (!window)
    return;

  sl_destroy_window(window);
}

void sl_handle_reparent_notify(struct sl_context* ctx,
                               xcb_reparent_notify_event_t* event) {
  struct sl_window* window;

  if (event->parent == ctx->screen->root) {
    int width = 1;
    int height = 1;
    int border_width = 0;

    // Return early if window is already tracked. This happens when we
    // reparent an unampped window back to the root window.
    window = sl_lookup_window(ctx, event->window);
    if (window)
      return;

    xcb_get_geometry_reply_t* geometry_reply = xcb_get_geometry_reply(
        ctx->connection, xcb_get_geometry(ctx->connection, event->window),
        NULL);

    if (geometry_reply) {
      width = geometry_reply->width;
      height = geometry_reply->height;
      border_width = geometry_reply->border_width;
      free(geometry_reply);
    }
    sl_create_window(ctx, event->window, event->x, event->y, width, height,
                     border_width);
    return;
  }

  if (sl_is_our_window(ctx, event->parent))
    return;

  window = sl_lookup_window(ctx, event->window);
  if (!window)
    return;

  sl_destroy_window(window);
}

static const char* sl_decode_wm_class(struct sl_window* window,
                                      xcb_get_property_reply_t* reply) {
  // WM_CLASS property contains two consecutive null-terminated strings.
  // These specify the Instance and Class names. If a global app ID is
  // not set then use Class name for app ID.
  const char* value = static_cast<char*>(xcb_get_property_value(reply));
  int value_length = xcb_get_property_value_length(reply);
  int instance_length = strnlen(value, value_length);
  if (value_length > instance_length) {
    window->clazz = strndup(value + instance_length + 1,
                            value_length - instance_length - 1);
    return window->clazz;
  }
  return nullptr;
}

static void sl_set_application_id_from_atom(struct sl_context* ctx,
                                            struct sl_window* window,
                                            xcb_get_property_reply_t* reply) {
  if (reply->type == XCB_ATOM_CARDINAL) {
    uint32_t value = *static_cast<uint32_t*>(xcb_get_property_value(reply));
    window->app_id_property = std::to_string(value);
  }
}

void sl_handle_map_request(struct sl_context* ctx,
                           xcb_map_request_event_t* event) {
  TRACE_EVENT("shm", "sl_handle_map_request", [&](perfetto::EventContext p) {
    perfetto_annotate_window(ctx, p, "window", event->window);
  });
  struct sl_window* window = sl_lookup_window(ctx, event->window);
  struct {
    int type;
    xcb_atom_t atom;
  } properties[] = {
      {PROPERTY_WM_NAME, XCB_ATOM_WM_NAME},
      {PROPERTY_NET_WM_NAME, ctx->atoms[ATOM_NET_WM_NAME].value},
      {PROPERTY_WM_CLASS, XCB_ATOM_WM_CLASS},
      {PROPERTY_WM_TRANSIENT_FOR, XCB_ATOM_WM_TRANSIENT_FOR},
      {PROPERTY_WM_NORMAL_HINTS, XCB_ATOM_WM_NORMAL_HINTS},
      {PROPERTY_WM_CLIENT_LEADER, ctx->atoms[ATOM_WM_CLIENT_LEADER].value},
      {PROPERTY_WM_PROTOCOLS, ctx->atoms[ATOM_WM_PROTOCOLS].value},
      {PROPERTY_MOTIF_WM_HINTS, ctx->atoms[ATOM_MOTIF_WM_HINTS].value},
      {PROPERTY_NET_STARTUP_ID, ctx->atoms[ATOM_NET_STARTUP_ID].value},
      {PROPERTY_NET_WM_STATE, ctx->atoms[ATOM_NET_WM_STATE].value},
      {PROPERTY_GTK_THEME_VARIANT, ctx->atoms[ATOM_GTK_THEME_VARIANT].value},
      {PROPERTY_XWAYLAND_RANDR_EMU_MONITOR_RECTS,
       ctx->atoms[ATOM_XWAYLAND_RANDR_EMU_MONITOR_RECTS].value},
      {PROPERTY_SPECIFIED_FOR_APP_ID, ctx->application_id_property_atom},
  };
  xcb_get_geometry_cookie_t geometry_cookie;
  xcb_get_property_cookie_t property_cookies[ARRAY_SIZE(properties)];
  struct sl_wm_size_hints size_hints = {0};
  struct sl_mwm_hints mwm_hints = {0};
  bool maximize_h = false, maximize_v = false, fullscreen = false;
  uint32_t values[5];

  if (!window)
    return;

  if (sl_is_our_window(ctx, event->window))
    return;

  window->managed = 1;
  if (window->frame_id == XCB_WINDOW_NONE)
    geometry_cookie = xcb_get_geometry(ctx->connection, window->id);

  for (unsigned i = 0; i < ARRAY_SIZE(properties); ++i) {
    property_cookies[i] =
        xcb_get_property(ctx->connection, 0, window->id, properties[i].atom,
                         XCB_ATOM_ANY, 0, 2048);
  }

  if (window->frame_id == XCB_WINDOW_NONE) {
    xcb_get_geometry_reply_t* geometry_reply =
        xcb_get_geometry_reply(ctx->connection, geometry_cookie, NULL);
    if (geometry_reply) {
      window->x = geometry_reply->x;
      window->y = geometry_reply->y;
      window->width = geometry_reply->width;
      window->height = geometry_reply->height;
      window->depth = geometry_reply->depth;
      free(geometry_reply);
    }
  }

  free(window->name);
  window->name = NULL;
  free(window->clazz);
  window->clazz = NULL;
  free(window->startup_id);
  window->startup_id = NULL;
  window->transient_for = XCB_WINDOW_NONE;
  window->client_leader = XCB_WINDOW_NONE;
  window->decorated = 1;
  window->size_flags = 0;
  window->dark_frame = 0;

  for (unsigned i = 0; i < ARRAY_SIZE(properties); ++i) {
    xcb_get_property_reply_t* reply =
        xcb_get_property_reply(ctx->connection, property_cookies[i], NULL);

    if (!reply)
      continue;

    if (reply->type == XCB_ATOM_NONE) {
      free(reply);
      continue;
    }

    const char* value = nullptr;
    int value_int = std::numeric_limits<int>::max();
    xcb_atom_t* reply_atoms = nullptr;

    switch (properties[i].type) {
      case PROPERTY_WM_NAME:
        // WM_NAME is only used for the window name if _NET_WM_NAME is not
        // present or not yet processed, thus window->name is null.
        if (!window->has_net_wm_name) {
          window->name =
              strndup(static_cast<char*>(xcb_get_property_value(reply)),
                      xcb_get_property_value_length(reply));
          value = window->name;
        }
        break;
      case PROPERTY_NET_WM_NAME:
        // _NET_WM_NAME is the preferred window name property. Remove any
        // previously set window name.
        if (window->name) {
          free(window->name);
          window->name = nullptr;
        }
        window->has_net_wm_name = true;
        window->name =
            strndup(static_cast<char*>(xcb_get_property_value(reply)),
                    xcb_get_property_value_length(reply));
        value = window->name;
        break;
      case PROPERTY_WM_CLASS:
        value = sl_decode_wm_class(window, reply);
        if (!value)
          value = "<invalid>";
        break;
      case PROPERTY_WM_TRANSIENT_FOR:
        if (xcb_get_property_value_length(reply) >= 4) {
          window->transient_for =
              *(reinterpret_cast<uint32_t*>(xcb_get_property_value(reply)));
          value_int = window->transient_for;
        }
        break;
      case PROPERTY_WM_NORMAL_HINTS:
        if (xcb_get_property_value_length(reply) >=
            static_cast<int>(sizeof(size_hints)))
          memcpy(&size_hints, xcb_get_property_value(reply),
                 sizeof(size_hints));
        break;
      case PROPERTY_WM_CLIENT_LEADER:
        if (xcb_get_property_value_length(reply) >= 4) {
          window->client_leader =
              *(reinterpret_cast<uint32_t*>(xcb_get_property_value(reply)));
          value_int = window->client_leader;
        }
        break;
      case PROPERTY_WM_PROTOCOLS:
        reply_atoms = static_cast<xcb_atom_t*>(xcb_get_property_value(reply));
        for (unsigned j = 0;
             j < xcb_get_property_value_length(reply) / sizeof(xcb_atom_t);
             ++j) {
          if (reply_atoms[j] == ctx->atoms[ATOM_WM_TAKE_FOCUS].value) {
            window->focus_model_take_focus = 1;
            value = "ATOM_WM_TAKE_FOCUS";
          }
        }
        break;
      case PROPERTY_MOTIF_WM_HINTS:
        if (xcb_get_property_value_length(reply) >=
            static_cast<int>(sizeof(mwm_hints)))
          memcpy(&mwm_hints, xcb_get_property_value(reply), sizeof(mwm_hints));
        break;
      case PROPERTY_NET_STARTUP_ID:
        window->startup_id =
            strndup(static_cast<char*>(xcb_get_property_value(reply)),
                    xcb_get_property_value_length(reply));
        value = window->startup_id;
        break;
      case PROPERTY_NET_WM_STATE:
        reply_atoms = static_cast<xcb_atom_t*>(xcb_get_property_value(reply));
        for (unsigned j = 0;
             j < xcb_get_property_value_length(reply) / sizeof(xcb_atom_t);
             ++j) {
          if (reply_atoms[j] ==
              ctx->atoms[ATOM_NET_WM_STATE_MAXIMIZED_HORZ].value) {
            maximize_h = true;
          } else if (reply_atoms[j] ==
                     ctx->atoms[ATOM_NET_WM_STATE_MAXIMIZED_VERT].value) {
            maximize_v = true;
          } else if (reply_atoms[j] ==
                     ctx->atoms[ATOM_NET_WM_STATE_FULLSCREEN].value) {
            fullscreen = true;
          }
        }
        // Neither wayland not CrOS support 1D maximizing, so sommelier will
        // only consider a window maximized if both dimensions are. This
        // behaviour is consistent with sl_handle_client_message().
        window->maximized = maximize_h && maximize_v;
        window->fullscreen = fullscreen;
        if (window->maximized) {
          if (window->fullscreen) {
            value =
                "_NET_WM_STATE_FULLSCREEN, _NET_WM_STATE_MAXIMIZED_VERT && "
                "HORZ";
          } else {
            value = "_NET_WM_STATE_MAXIMIZED_VERT && HORZ";
          }
        } else if (window->fullscreen) {
          value = "_NET_WM_STATE_FULLSCREEN";
        }
        break;
      case PROPERTY_GTK_THEME_VARIANT:
        if (xcb_get_property_value_length(reply) >= 4)
          window->dark_frame = !strcmp(
              static_cast<char*>(xcb_get_property_value(reply)), "dark");
        break;
      case PROPERTY_SPECIFIED_FOR_APP_ID:
        sl_set_application_id_from_atom(ctx, window, reply);
        value = window->app_id_property.c_str();
        break;
      default:
        break;
    }

    TRACE_EVENT("x11wm", "XCB_MAP_REQUEST: X property",
                [&](perfetto::EventContext p) {
                  perfetto_annotate_atom(ctx, p, "name", properties[i].atom);

                  if (value_int != std::numeric_limits<int>::max()) {
                    auto* dbg = p.event()->add_debug_annotations();
                    dbg->set_name("int value");
                    dbg->set_int_value(value_int);
                  }
                  if (value) {
                    auto* dbg = p.event()->add_debug_annotations();
                    dbg->set_name("str value");
                    dbg->set_string_value(value, strlen(value));
                  }

                  switch (properties[i].type) {
                    case PROPERTY_WM_NORMAL_HINTS:
                      perfetto_annotate_size_hints(p, size_hints);
                      break;
                    case PROPERTY_XWAYLAND_RANDR_EMU_MONITOR_RECTS:
                      perfetto_annotate_cardinal_list(p, "value", reply);
                      break;
                  }
                });

    free(reply);
  }

  if (mwm_hints.flags & MWM_HINTS_DECORATIONS) {
    if (mwm_hints.decorations & MWM_DECOR_ALL)
      window->decorated = ~mwm_hints.decorations & MWM_DECOR_TITLE;
    else
      window->decorated = mwm_hints.decorations & MWM_DECOR_TITLE;
  }

  // Allow user/program controlled position for transients.
  if (window->transient_for)
    window->size_flags |= size_hints.flags & (US_POSITION | P_POSITION);

  // If startup ID is not set, then try the client leader window.
  if (!window->startup_id && window->client_leader) {
    xcb_get_property_reply_t* reply = xcb_get_property_reply(
        ctx->connection,
        xcb_get_property(ctx->connection, 0, window->client_leader,
                         ctx->atoms[ATOM_NET_STARTUP_ID].value, XCB_ATOM_ANY, 0,
                         2048),
        NULL);
    if (reply) {
      if (reply->type != XCB_ATOM_NONE) {
        window->startup_id =
            strndup(static_cast<char*>(xcb_get_property_value(reply)),
                    xcb_get_property_value_length(reply));
      }
      free(reply);
    }
  }

  window->size_flags |= size_hints.flags & (P_MIN_SIZE | P_MAX_SIZE);
  if (window->size_flags & P_MIN_SIZE) {
    window->min_width = size_hints.min_width;
    window->min_height = size_hints.min_height;
  }
  if (window->size_flags & P_MAX_SIZE) {
    window->max_width = size_hints.max_width;
    window->max_height = size_hints.max_height;
  }

  window->border_width = 0;
  sl_adjust_window_size_for_screen_size(window);
  if (!(window->size_flags & (US_POSITION | P_POSITION)))
    sl_adjust_window_position_for_screen_size(window);

  values[0] = window->width;
  values[1] = window->height;
  values[2] = 0;
  xcb_configure_window(ctx->connection, window->id,
                       XCB_CONFIG_WINDOW_WIDTH | XCB_CONFIG_WINDOW_HEIGHT |
                           XCB_CONFIG_WINDOW_BORDER_WIDTH,
                       values);
  // This needs to match the frame extents of the X11 frame window used
  // for reparenting or applications tend to be confused. The actual window
  // frame size used by the host compositor can be different.
  values[0] = 0;
  values[1] = 0;
  values[2] = 0;
  values[3] = 0;
  xcb_change_property(ctx->connection, XCB_PROP_MODE_REPLACE, window->id,
                      ctx->atoms[ATOM_NET_FRAME_EXTENTS].value,
                      XCB_ATOM_CARDINAL, 32, 4, values);

  // Remove weird gravities.
  values[0] = XCB_GRAVITY_NORTH_WEST;
  xcb_change_window_attributes(ctx->connection, window->id, XCB_CW_WIN_GRAVITY,
                               values);

  if (window->frame_id == XCB_WINDOW_NONE) {
    int depth = window->depth ? window->depth : ctx->screen->root_depth;

    values[0] = ctx->screen->black_pixel;
    values[1] = XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY |
                XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT;
    values[2] = ctx->colormaps[depth];

    window->frame_id = xcb_generate_id(ctx->connection);
    xcb_create_window(
        ctx->connection, depth, window->frame_id, ctx->screen->root, window->x,
        window->y, window->width, window->height, 0,
        XCB_WINDOW_CLASS_INPUT_OUTPUT, ctx->visual_ids[depth],
        XCB_CW_BORDER_PIXEL | XCB_CW_EVENT_MASK | XCB_CW_COLORMAP, values);
    values[0] = XCB_STACK_MODE_BELOW;
    xcb_configure_window(ctx->connection, window->frame_id,
                         XCB_CONFIG_WINDOW_STACK_MODE, values);
    xcb_reparent_window(ctx->connection, window->id, window->frame_id, 0, 0);
  } else {
    values[0] = window->x;
    values[1] = window->y;
    values[2] = window->width;
    values[3] = window->height;
    values[4] = XCB_STACK_MODE_BELOW;
    xcb_configure_window(
        ctx->connection, window->frame_id,
        XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y | XCB_CONFIG_WINDOW_WIDTH |
            XCB_CONFIG_WINDOW_HEIGHT | XCB_CONFIG_WINDOW_STACK_MODE,
        values);
  }

  sl_window_set_wm_state(window, WM_STATE_NORMAL);
  sl_send_configure_notify(window);

  xcb_map_window(ctx->connection, window->id);
  xcb_map_window(ctx->connection, window->frame_id);
}

static void sl_handle_map_notify(struct sl_context* ctx,
                                 xcb_map_notify_event_t* event) {}

void sl_handle_unmap_notify(struct sl_context* ctx,
                            xcb_unmap_notify_event_t* event) {
  struct sl_window* window;

  if (sl_is_our_window(ctx, event->window))
    return;

  if (event->response_type & SEND_EVENT_MASK)
    return;

  window = sl_lookup_window(ctx, event->window);
  if (!window)
    return;

  if (ctx->host_focus_window == window) {
    ctx->host_focus_window = NULL;
    ctx->needs_set_input_focus = 1;
  }

  if (window->host_surface_id) {
    window->host_surface_id = 0;
    sl_window_update(window);
  }

  sl_window_set_wm_state(window, WM_STATE_WITHDRAWN);

  // Reparent window and destroy frame if it exists.
  if (window->frame_id != XCB_WINDOW_NONE) {
    xcb_reparent_window(ctx->connection, window->id, ctx->screen->root,
                        window->x, window->y);
    xcb_destroy_window(ctx->connection, window->frame_id);
    window->frame_id = XCB_WINDOW_NONE;
  }

  // Reset properties to unmanaged state in case the window transitions to
  // an override-redirect window.
  window->managed = 0;
  window->decorated = 0;
  window->size_flags = P_POSITION;
}

void sl_handle_configure_request(struct sl_context* ctx,
                                 xcb_configure_request_event_t* event) {
  struct sl_window* window = sl_lookup_window(ctx, event->window);
  if (!window)
    return;
  int width = window->width;
  int height = window->height;
  uint32_t values[7];

  if (sl_is_our_window(ctx, event->window))
    return;

  if (!window->managed) {
    int i = 0;

    if (event->value_mask & XCB_CONFIG_WINDOW_X)
      values[i++] = event->x;
    if (event->value_mask & XCB_CONFIG_WINDOW_Y)
      values[i++] = event->y;
    if (event->value_mask & XCB_CONFIG_WINDOW_WIDTH)
      values[i++] = event->width;
    if (event->value_mask & XCB_CONFIG_WINDOW_HEIGHT)
      values[i++] = event->height;
    if (event->value_mask & XCB_CONFIG_WINDOW_BORDER_WIDTH)
      values[i++] = event->border_width;
    if (event->value_mask & XCB_CONFIG_WINDOW_SIBLING)
      values[i++] = event->sibling;
    if (event->value_mask & XCB_CONFIG_WINDOW_STACK_MODE)
      values[i++] = event->stack_mode;

    xcb_configure_window(ctx->connection, window->id, event->value_mask,
                         values);
    return;
  }

  // Ack configure events as satisfying request removes the guarantee
  // that matching contents will arrive.
  if (window->xdg_toplevel) {
    if (window->pending_config.serial) {
      xdg_surface_ack_configure(window->xdg_surface,
                                window->pending_config.serial);
      window->pending_config.serial = 0;
      window->pending_config.mask = 0;
      window->pending_config.states_length = 0;
    }
    if (window->next_config.serial) {
      xdg_surface_ack_configure(window->xdg_surface,
                                window->next_config.serial);
      window->next_config.serial = 0;
      window->next_config.mask = 0;
      window->next_config.states_length = 0;
    }
  }

  if (event->value_mask & XCB_CONFIG_WINDOW_X)
    window->x = event->x;
  if (event->value_mask & XCB_CONFIG_WINDOW_Y)
    window->y = event->y;

  if (window->allow_resize) {
    if (event->value_mask & XCB_CONFIG_WINDOW_WIDTH)
      window->width = event->width;
    if (event->value_mask & XCB_CONFIG_WINDOW_HEIGHT)
      window->height = event->height;
  }

  sl_adjust_window_size_for_screen_size(window);
  if (window->size_flags & (US_POSITION | P_POSITION))
    sl_window_update(window);
  else
    sl_adjust_window_position_for_screen_size(window);

  values[0] = window->x;
  values[1] = window->y;
  values[2] = window->width;
  values[3] = window->height;
  values[4] = 0;
  xcb_configure_window(ctx->connection, window->frame_id,
                       XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y |
                           XCB_CONFIG_WINDOW_WIDTH | XCB_CONFIG_WINDOW_HEIGHT,
                       values);

  // We need to send a synthetic configure notify if:
  // - Not changing the size, location, border width.
  // - Moving the window without resizing it or changing its border width.
  if (width != window->width || height != window->height ||
      window->border_width) {
    xcb_configure_window(ctx->connection, window->id,
                         XCB_CONFIG_WINDOW_WIDTH | XCB_CONFIG_WINDOW_HEIGHT |
                             XCB_CONFIG_WINDOW_BORDER_WIDTH,
                         &values[2]);
    window->border_width = 0;
  } else {
    sl_send_configure_notify(window);
  }
}

static void sl_handle_configure_notify(struct sl_context* ctx,
                                       xcb_configure_notify_event_t* event) {
  struct sl_window* window;

  if (sl_is_our_window(ctx, event->window))
    return;

  if (event->window == ctx->screen->root) {
    xcb_get_geometry_reply_t* geometry_reply = xcb_get_geometry_reply(
        ctx->connection, xcb_get_geometry(ctx->connection, event->window),
        NULL);
    int width = ctx->screen->width_in_pixels;
    int height = ctx->screen->height_in_pixels;

    if (geometry_reply) {
      width = geometry_reply->width;
      height = geometry_reply->height;
      free(geometry_reply);
    }

    if (width == ctx->screen->width_in_pixels ||
        height == ctx->screen->height_in_pixels) {
      return;
    }

    ctx->screen->width_in_pixels = width;
    ctx->screen->height_in_pixels = height;

    // Re-center managed windows.
    wl_list_for_each(window, &ctx->windows, link) {
      int x, y;

      if (window->size_flags & (US_POSITION | P_POSITION))
        continue;

      x = window->x;
      y = window->y;
      sl_adjust_window_position_for_screen_size(window);
      if (window->x != x || window->y != y) {
        uint32_t values[2];

        values[0] = window->x;
        values[1] = window->y;
        xcb_configure_window(ctx->connection, window->frame_id,
                             XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y, values);
        sl_send_configure_notify(window);
      }
    }
    return;
  }

  window = sl_lookup_window(ctx, event->window);
  if (!window)
    return;

  if (window->managed)
    return;

  window->width = event->width;
  window->height = event->height;
  window->border_width = event->border_width;
  if (event->x != window->x || event->y != window->y) {
    window->x = event->x;
    window->y = event->y;
    sl_window_update(window);
  }
}

static uint32_t sl_resize_edge(int net_wm_moveresize_size) {
  switch (net_wm_moveresize_size) {
    case NET_WM_MOVERESIZE_SIZE_TOPLEFT:
      return XDG_TOPLEVEL_RESIZE_EDGE_TOP_LEFT;
    case NET_WM_MOVERESIZE_SIZE_TOP:
      return XDG_TOPLEVEL_RESIZE_EDGE_TOP;
    case NET_WM_MOVERESIZE_SIZE_TOPRIGHT:
      return XDG_TOPLEVEL_RESIZE_EDGE_TOP_RIGHT;
    case NET_WM_MOVERESIZE_SIZE_RIGHT:
      return XDG_TOPLEVEL_RESIZE_EDGE_RIGHT;
    case NET_WM_MOVERESIZE_SIZE_BOTTOMRIGHT:
      return XDG_TOPLEVEL_RESIZE_EDGE_BOTTOM_RIGHT;
    case NET_WM_MOVERESIZE_SIZE_BOTTOM:
      return XDG_TOPLEVEL_RESIZE_EDGE_BOTTOM;
    case NET_WM_MOVERESIZE_SIZE_BOTTOMLEFT:
      return XDG_TOPLEVEL_RESIZE_EDGE_BOTTOM_LEFT;
    case NET_WM_MOVERESIZE_SIZE_LEFT:
      return XDG_TOPLEVEL_RESIZE_EDGE_LEFT;
    default:
      return XDG_TOPLEVEL_RESIZE_EDGE_NONE;
  }
}

static void sl_request_attention(struct sl_context* ctx,
                                 struct sl_window* window,
                                 bool is_strong_request) {
  if (!window->aura_surface ||
      ctx->aura_shell->version < ZAURA_SURFACE_DRAW_ATTENTION_SINCE_VERSION)
    return;
  if (is_strong_request) {
    zaura_surface_activate(window->aura_surface);
  } else {
    zaura_surface_draw_attention(window->aura_surface);
  }
}

void sl_handle_client_message(struct sl_context* ctx,
                              xcb_client_message_event_t* event) {
  TRACE_EVENT("x11wm", "XCB_CLIENT_MESSAGE", [&](perfetto::EventContext p) {
    perfetto_annotate_atom(ctx, p, "event->type", event->type);
    perfetto_annotate_window(ctx, p, "event->window", event->window);
  });
  if (event->type == ctx->atoms[ATOM_WL_SURFACE_ID].value) {
    struct sl_window *window, *unpaired_window = NULL;

    wl_list_for_each(window, &ctx->unpaired_windows, link) {
      if (sl_is_window(window, event->window)) {
        unpaired_window = window;
        break;
      }
    }

    if (unpaired_window) {
      unpaired_window->host_surface_id = event->data.data32[0];
      sl_window_update(unpaired_window);
    }
  } else if (event->type == ctx->atoms[ATOM_NET_ACTIVE_WINDOW].value) {
    struct sl_window* window = sl_lookup_window(ctx, event->window);
    if (window)
      sl_request_attention(ctx, window, /*is_strong_request=*/true);
  } else if (event->type == ctx->atoms[ATOM_NET_WM_MOVERESIZE].value) {
    struct sl_window* window = sl_lookup_window(ctx, event->window);

    if (window && window->xdg_toplevel) {
      struct sl_host_seat* seat = window->ctx->default_seat;

      if (!seat)
        return;

      if (event->data.data32[2] == NET_WM_MOVERESIZE_MOVE) {
        xdg_toplevel_move(window->xdg_toplevel, seat->proxy,
                          seat->seat->last_serial);
      } else {
        uint32_t edge = sl_resize_edge(event->data.data32[2]);

        if (edge == XDG_TOPLEVEL_RESIZE_EDGE_NONE)
          return;

        xdg_toplevel_resize(window->xdg_toplevel, seat->proxy,
                            seat->seat->last_serial, edge);
      }
    }
  } else if (event->type == ctx->atoms[ATOM_NET_WM_STATE].value) {
    struct sl_window* window = sl_lookup_window(ctx, event->window);

    if (window) {
      int changed[ATOM_LAST + 1];
      uint32_t action = event->data.data32[0];
      unsigned i;

      for (i = 0; i < ARRAY_SIZE(ctx->atoms); ++i) {
        changed[i] = event->data.data32[1] == ctx->atoms[i].value ||
                     event->data.data32[2] == ctx->atoms[i].value;
      }

      if (changed[ATOM_NET_WM_STATE_FULLSCREEN]) {
        TRACE_EVENT("x11wm", "XCB_CLIENT_MESSAGE: ATOM_NET_WM_STATE_FULLSCREEN",
                    "action", net_wm_state_to_string(action), "window->name",
                    window->name);
        if (action == NET_WM_STATE_ADD) {
          window->fullscreen = 1;
          if (window->xdg_toplevel && !window->iconified) {
            xdg_toplevel_set_fullscreen(window->xdg_toplevel, NULL);
          } else {
            window->pending_fullscreen_change = true;
          }
        } else if (action == NET_WM_STATE_REMOVE) {
          window->fullscreen = 0;
          if (window->xdg_toplevel && !window->iconified) {
            xdg_toplevel_unset_fullscreen(window->xdg_toplevel);
          } else {
            window->pending_fullscreen_change = true;
          }
        }
      }

      if (changed[ATOM_NET_WM_STATE_MAXIMIZED_VERT] &&
          changed[ATOM_NET_WM_STATE_MAXIMIZED_HORZ]) {
        TRACE_EVENT(
            "x11wm",
            "XCB_CLIENT_MESSAGE: ATOM_NET_WM_STATE_MAXIMIZED_VERT && HORZ",
            "action", net_wm_state_to_string(action), "window->name",
            window->name);
        if (action == NET_WM_STATE_ADD) {
          window->maximized = 1;
          if (window->xdg_toplevel && !window->iconified) {
            xdg_toplevel_set_maximized(window->xdg_toplevel);
          } else {
            window->pending_maximized_change = true;
          }
        } else if (action == NET_WM_STATE_REMOVE) {
          window->maximized = 0;
          if (window->xdg_toplevel && !window->iconified) {
            xdg_toplevel_unset_maximized(window->xdg_toplevel);
          } else {
            window->pending_maximized_change = true;
          }
        }
      }
    }
  } else if (event->type == ctx->atoms[ATOM_WM_CHANGE_STATE].value &&
             event->data.data32[0] == WM_STATE_ICONIC) {
    struct sl_window* window = sl_lookup_window(ctx, event->window);
    TRACE_EVENT("x11wm", "XCB_CLIENT_MESSAGE: WM_STATE_ICONIC (minimize)",
                "window->name", window ? window->name : "<unknown>");
    if (window && window->xdg_toplevel) {
      xdg_toplevel_set_minimized(window->xdg_toplevel);
#ifdef BLACK_SCREEN_FIX
      // Workaround for some borealis apps showing a black screen after losing
      // focus from fullscreen.
      // When a window is iconified, it should be unmapped. To return it back
      // to a visible state, it should be remapped. However sommelier does not
      // do this. Therefore we are sending a synthetic unmap then map notify
      // so that the app is rendered again.
      xcb_unmap_notify_event_t unmap_event = {.response_type = XCB_UNMAP_NOTIFY,
                                              .pad0 = 0,
                                              .event = window->id,
                                              .window = window->id,
                                              .from_configure = 0};

      xcb_send_event(ctx->connection, 0, window->id,
                     XCB_EVENT_MASK_STRUCTURE_NOTIFY,
                     reinterpret_cast<char*>(&unmap_event));
      sl_send_configure_notify(window);

      sl_window_set_wm_state(window, WM_STATE_ICONIC);
      sl_send_configure_notify(window);

      xcb_map_notify_event_t map_event = {.response_type = XCB_MAP_NOTIFY,
                                          .pad0 = 0,
                                          .event = window->id,
                                          .window = window->id,
                                          .override_redirect = 0};

      xcb_send_event(ctx->connection, 0, window->id,
                     XCB_EVENT_MASK_STRUCTURE_NOTIFY,
                     reinterpret_cast<char*>(&map_event));
      sl_send_configure_notify(window);

      sl_window_set_wm_state(window, WM_STATE_NORMAL);
      sl_send_configure_notify(window);

      sl_set_input_focus(ctx, nullptr);
      xcb_flush(ctx->connection);

      // When we are iconified we want to suppress any calls that deiconify
      // the window as it should in theory be unmapped.
      window->iconified = 1;
#endif
    }
  }
}

void sl_handle_focus_in(struct sl_context* ctx, xcb_focus_in_event_t* event) {
  struct sl_window* window = sl_lookup_window(ctx, event->event);
  if (window && window->transient_for != XCB_WINDOW_NONE) {
    // Set our parent now as it might not have been set properly when the
    // window was realized.
    struct sl_window* parent = sl_lookup_window(ctx, window->transient_for);
    if (parent && parent->xdg_toplevel && window->xdg_toplevel)
      xdg_toplevel_set_parent(window->xdg_toplevel, parent->xdg_toplevel);
  }
  if (window) {
    if (window->xdg_toplevel && window->pending_fullscreen_change) {
      if (window->fullscreen) {
        xdg_toplevel_set_fullscreen(window->xdg_toplevel, NULL);
      } else {
        xdg_toplevel_unset_fullscreen(window->xdg_toplevel);
      }

      window->pending_fullscreen_change = false;
    }
    if (window->xdg_toplevel && window->pending_maximized_change) {
      if (window->maximized) {
        xdg_toplevel_set_maximized(window->xdg_toplevel);
      } else {
        xdg_toplevel_unset_maximized(window->xdg_toplevel);
      }
      window->pending_maximized_change = false;
    }
    window->iconified = 0;
  }
}

static void sl_handle_focus_out(struct sl_context* ctx,
                                xcb_focus_out_event_t* event) {}

int sl_begin_data_source_send(struct sl_context* ctx,
                              int fd,
                              xcb_intern_atom_cookie_t cookie,
                              struct sl_data_source* data_source) {
  xcb_intern_atom_reply_t* reply =
      xcb_intern_atom_reply(ctx->connection, cookie, NULL);

  if (!reply) {
    close(fd);
    return 0;
  }

  int flags, rv;

  xcb_convert_selection(ctx->connection, ctx->selection_window,
                        ctx->atoms[ATOM_CLIPBOARD].value, reply->atom,
                        ctx->atoms[ATOM_WL_SELECTION].value, XCB_CURRENT_TIME);

  flags = fcntl(fd, F_GETFL, 0);
  rv = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
  errno_assert(!rv);

  ctx->selection_data_source_send_fd = fd;
  free(reply);
  return 1;
}

void sl_process_data_source_send_pending_list(struct sl_context* ctx) {
  while (!wl_list_empty(&ctx->selection_data_source_send_pending)) {
    struct wl_list* next = ctx->selection_data_source_send_pending.next;
    struct sl_data_source_send_request* request;
    request = wl_container_of(next, request, link);
    wl_list_remove(next);

    int rv = sl_begin_data_source_send(ctx, request->fd, request->cookie,
                                       request->data_source);
    free(request);
    if (rv)
      break;
  }
}

static int sl_handle_selection_fd_writable(int fd, uint32_t mask, void* data) {
  struct sl_context* ctx = static_cast<sl_context*>(data);
  int bytes, bytes_left;

  uint8_t* value = static_cast<uint8_t*>(
      xcb_get_property_value(ctx->selection_property_reply));
  bytes_left = xcb_get_property_value_length(ctx->selection_property_reply) -
               ctx->selection_property_offset;

  bytes = write(fd, value + ctx->selection_property_offset, bytes_left);
  if (bytes == -1) {
    fprintf(stderr, "write error to target fd: %m\n");
    close(fd);
    fd = -1;
  } else if (bytes == bytes_left) {
    if (ctx->selection_incremental_transfer) {
      xcb_delete_property(ctx->connection, ctx->selection_window,
                          ctx->atoms[ATOM_WL_SELECTION].value);
    } else {
      close(fd);
      fd = -1;
    }
  } else {
    ctx->selection_property_offset += bytes;
    return 1;
  }

  free(ctx->selection_property_reply);
  ctx->selection_property_reply = NULL;
  if (ctx->selection_send_event_source) {
    ctx->selection_send_event_source.reset();
  }
  if (fd < 0) {
    ctx->selection_data_source_send_fd = -1;
    sl_process_data_source_send_pending_list(ctx);
  }
  return 1;
}

static void sl_write_selection_property(struct sl_context* ctx,
                                        xcb_get_property_reply_t* reply) {
  ctx->selection_property_offset = 0;
  ctx->selection_property_reply = reply;
  sl_handle_selection_fd_writable(ctx->selection_data_source_send_fd,
                                  WL_EVENT_WRITABLE, ctx);

  if (!ctx->selection_property_reply)
    return;

  assert(!ctx->selection_send_event_source);
  ctx->selection_send_event_source.reset(wl_event_loop_add_fd(
      wl_display_get_event_loop(ctx->host_display),
      ctx->selection_data_source_send_fd, WL_EVENT_WRITABLE,
      sl_handle_selection_fd_writable, ctx));
}

static void sl_send_selection_notify(struct sl_context* ctx,
                                     xcb_atom_t property) {
  TRACE_EVENT("other", "sl_send_selection_notify");
  xcb_selection_notify_event_t event = {
      .response_type = XCB_SELECTION_NOTIFY,
      .pad0 = 0,
      .sequence = 0,
      .time = ctx->selection_request.time,
      .requestor = ctx->selection_request.requestor,
      .selection = ctx->selection_request.selection,
      .target = ctx->selection_request.target,
      .property = property};

  xcb_send_event(ctx->connection, 0, ctx->selection_request.requestor,
                 XCB_EVENT_MASK_NO_EVENT, reinterpret_cast<char*>(&event));
}

static void sl_send_selection_data(struct sl_context* ctx) {
  assert(!ctx->selection_data_ack_pending);
  xcb_change_property(
      ctx->connection, XCB_PROP_MODE_REPLACE, ctx->selection_request.requestor,
      ctx->selection_request.property, ctx->selection_data_type,
      /*format=*/8, ctx->selection_data.size, ctx->selection_data.data);
  ctx->selection_data_ack_pending = 1;
  ctx->selection_data.size = 0;
}

static const uint32_t sl_incr_chunk_size = 64 * 1024;

static int sl_handle_selection_fd_readable(int fd, uint32_t mask, void* data) {
  struct sl_context* ctx = static_cast<sl_context*>(data);

  // When a selection starts, the wl_array in |ctx->selection_data| is
  // initialized with a size of zero. Since we now need to actually write into
  // it, allocate |sl_incr_chunk_size| bytes to store the selection data in. We
  // need to buffer this much to decide between a one-shot transfer and an
  // incremental transfer, as this decision must be made before the first
  // response is sent.
  if (ctx->selection_data.alloc == 0) {
    // wl_array_add is ostensibly failable, but the only failure case comes from
    // calling malloc, and if that fails we should just die anyway.
    errno_assert(
        (size_t)wl_array_add(&ctx->selection_data, sl_incr_chunk_size));

    // wl_array_add increments |size| as well as |alloc|, but we don't actually
    // want that yet. Instead we will set |size| later based on the results of
    // the read call.
    ctx->selection_data.size -= sl_incr_chunk_size;
  }

  int offset = ctx->selection_data.size;
  void* p = reinterpret_cast<char*>(ctx->selection_data.data) + offset;
  int bytes_left = ctx->selection_data.alloc - offset;

  int bytes = read(fd, p, bytes_left);
  if (bytes == -1) {
    fprintf(stderr, "read error from data source: %m\n");
    sl_send_selection_notify(ctx, XCB_ATOM_NONE);
    ctx->selection_data_offer_receive_fd = -1;
    close(fd);
  } else {
    ctx->selection_data.size = offset + bytes;
    if (ctx->selection_data.size >= sl_incr_chunk_size) {
      if (!ctx->selection_incremental_transfer) {
        ctx->selection_incremental_transfer = 1;
        xcb_change_property(
            ctx->connection, XCB_PROP_MODE_REPLACE,
            ctx->selection_request.requestor, ctx->selection_request.property,
            ctx->atoms[ATOM_INCR].value, 32, 1, &sl_incr_chunk_size);
        ctx->selection_data_ack_pending = 1;
        sl_send_selection_notify(ctx, ctx->selection_request.property);
      } else if (!ctx->selection_data_ack_pending) {
        sl_send_selection_data(ctx);
      }
    } else if (bytes == 0) {
      if (!ctx->selection_data_ack_pending)
        sl_send_selection_data(ctx);
      if (!ctx->selection_incremental_transfer) {
        sl_send_selection_notify(ctx, ctx->selection_request.property);
        ctx->selection_request.requestor = XCB_NONE;
        wl_array_release(&ctx->selection_data);
      }
      xcb_flush(ctx->connection);
      ctx->selection_data_offer_receive_fd = -1;
      close(fd);
    } else {
      ctx->selection_data.size = offset + bytes;
      return 1;
    }
  }

  ctx->selection_event_source.reset();
  return 1;
}

void sl_handle_property_notify(struct sl_context* ctx,
                               xcb_property_notify_event_t* event) {
  TRACE_EVENT("x11wm", "XCB_PROPERTY_NOTIFY", [&](perfetto::EventContext p) {
    perfetto_annotate_atom(ctx, p, "event->atom", event->atom);
    perfetto_annotate_xcb_property_state(p, "event->state", event->state);
    perfetto_annotate_window(ctx, p, "event->window", event->window);
  });
  if (event->atom == XCB_ATOM_WM_NAME ||
      event->atom == ctx->atoms[ATOM_NET_WM_NAME].value) {
    struct sl_window* window = sl_lookup_window(ctx, event->window);
    if (!window)
      return;

    bool atom_is_net_wm_name =
        event->atom == ctx->atoms[ATOM_NET_WM_NAME].value;

    // If _NET_WM_NAME is set, ignore changes to WM_NAME.
    if (!atom_is_net_wm_name && window->has_net_wm_name)
      return;

    if (window->name) {
      free(window->name);
      window->name = NULL;
      window->has_net_wm_name = false;
    }

    xcb_atom_t atom = XCB_ATOM_NONE;
    if (event->state != XCB_PROPERTY_DELETE)
      atom = event->atom;
    else if (atom_is_net_wm_name)
      // If _NET_WM_NAME is deleted, fall back to WM_NAME if it is set.
      atom = XCB_ATOM_WM_NAME;

    if (atom != XCB_ATOM_NONE) {
      xcb_get_property_reply_t* reply = xcb_get_property_reply(
          ctx->connection,
          xcb_get_property(ctx->connection, 0, window->id, atom, XCB_ATOM_ANY,
                           0, 2048),
          NULL);
      if (reply) {
        window->name =
            strndup(static_cast<char*>(xcb_get_property_value(reply)),
                    xcb_get_property_value_length(reply));
        free(reply);

        if (atom == ctx->atoms[ATOM_NET_WM_NAME].value) {
          window->has_net_wm_name = true;
        }
      }
    }

    if (!window->xdg_toplevel)
      return;

    if (window->name) {
      xdg_toplevel_set_title(window->xdg_toplevel, window->name);
    } else {
      xdg_toplevel_set_title(window->xdg_toplevel, "");
    }
  } else if (event->atom == XCB_ATOM_WM_CLASS) {
    struct sl_window* window = sl_lookup_window(ctx, event->window);
    if (!window || event->state == XCB_PROPERTY_DELETE)
      return;

    xcb_get_property_cookie_t cookie =
        xcb_get_property(ctx->connection, 0, window->id, XCB_ATOM_WM_CLASS,
                         XCB_ATOM_ANY, 0, 2048);
    xcb_get_property_reply_t* reply =
        xcb_get_property_reply(ctx->connection, cookie, NULL);
    if (reply) {
      sl_decode_wm_class(window, reply);
      free(reply);
    }
    sl_update_application_id(ctx, window);
  } else if (event->atom == ctx->application_id_property_atom) {
    struct sl_window* window = sl_lookup_window(ctx, event->window);
    if (!window || event->state == XCB_PROPERTY_DELETE)
      return;

    // TODO(cpelling): Support other atom types (e.g. strings) if/when a use
    // case arises. The current use case is for cardinals (uint32) but this
    // is easy enough to extend later.
    xcb_get_property_cookie_t cookie = xcb_get_property(
        ctx->connection, 0, window->id, ctx->application_id_property_atom,
        XCB_ATOM_CARDINAL, 0, 1);
    xcb_get_property_reply_t* reply =
        xcb_get_property_reply(ctx->connection, cookie, NULL);
    if (reply) {
      sl_set_application_id_from_atom(ctx, window, reply);
      sl_update_application_id(ctx, window);
      free(reply);
    }
  } else if (event->atom == XCB_ATOM_WM_NORMAL_HINTS) {
    struct sl_window* window = sl_lookup_window(ctx, event->window);
    if (!window)
      return;

    window->size_flags &= ~(P_MIN_SIZE | P_MAX_SIZE);

    if (event->state != XCB_PROPERTY_DELETE) {
      struct sl_wm_size_hints size_hints = {0};
      xcb_get_property_reply_t* reply = xcb_get_property_reply(
          ctx->connection,
          xcb_get_property(ctx->connection, 0, window->id,
                           XCB_ATOM_WM_NORMAL_HINTS, XCB_ATOM_ANY, 0,
                           sizeof(size_hints)),
          NULL);
      if (reply) {
        memcpy(&size_hints, xcb_get_property_value(reply), sizeof(size_hints));
        free(reply);
      }
      TRACE_EVENT("x11wm", "XCB_PROPERTY_NOTIFY: XCB_ATOM_WM_NORMAL_HINTS",
                  [&](perfetto::EventContext p) {
                    perfetto_annotate_size_hints(p, size_hints);
                  });

      window->size_flags |= size_hints.flags & (P_MIN_SIZE | P_MAX_SIZE);
      if (window->size_flags & P_MIN_SIZE) {
        window->min_width = size_hints.min_width;
        window->min_height = size_hints.min_height;
      }
      if (window->size_flags & P_MAX_SIZE) {
        window->max_width = size_hints.max_width;
        window->max_height = size_hints.max_height;
      }
    }

    if (!window->xdg_toplevel)
      return;

    if (window->size_flags & P_MIN_SIZE) {
      int32_t minw = window->min_width;
      int32_t minh = window->min_height;

      sl_transform_guest_to_host(window->ctx, window->paired_surface, &minw,
                                 &minh);
      xdg_toplevel_set_min_size(window->xdg_toplevel, minw, minh);
    } else {
      xdg_toplevel_set_min_size(window->xdg_toplevel, 0, 0);
    }

    if (window->size_flags & P_MAX_SIZE) {
      int32_t maxw = window->max_width;
      int32_t maxh = window->max_height;

      sl_transform_guest_to_host(window->ctx, window->paired_surface, &maxw,
                                 &maxh);
      xdg_toplevel_set_max_size(window->xdg_toplevel, maxw, maxh);
    } else {
      xdg_toplevel_set_max_size(window->xdg_toplevel, 0, 0);
    }
  } else if (event->atom == XCB_ATOM_WM_HINTS) {
    struct sl_window* window = sl_lookup_window(ctx, event->window);
    if (!window)
      return;

    if (event->state == XCB_PROPERTY_DELETE)
      return;
    struct sl_wm_hints wm_hints = {0};
    xcb_get_property_reply_t* reply = xcb_get_property_reply(
        ctx->connection,
        xcb_get_property(ctx->connection, 0, window->id, XCB_ATOM_WM_HINTS,
                         XCB_ATOM_ANY, 0, sizeof(wm_hints)),
        NULL);

    if (!reply)
      return;
    memcpy(&wm_hints, xcb_get_property_value(reply), sizeof(wm_hints));
    free(reply);

    if (wm_hints.flags & WM_HINTS_FLAG_URGENCY) {
      sl_request_attention(ctx, window, /*is_strong_request=*/false);
    }
  } else if (event->atom == ctx->atoms[ATOM_MOTIF_WM_HINTS].value) {
    struct sl_window* window = sl_lookup_window(ctx, event->window);
    if (!window)
      return;

    // Managed windows are decorated by default.
    window->decorated = window->managed;

    if (event->state != XCB_PROPERTY_DELETE) {
      struct sl_mwm_hints mwm_hints = {0};
      xcb_get_property_reply_t* reply = xcb_get_property_reply(
          ctx->connection,
          xcb_get_property(ctx->connection, 0, window->id,
                           ctx->atoms[ATOM_MOTIF_WM_HINTS].value, XCB_ATOM_ANY,
                           0, sizeof(mwm_hints)),
          NULL);
      if (reply) {
        if (xcb_get_property_value_length(reply) >=
            static_cast<int>(sizeof(mwm_hints))) {
          memcpy(&mwm_hints, xcb_get_property_value(reply), sizeof(mwm_hints));
        }
        free(reply);
        if (mwm_hints.flags & MWM_HINTS_DECORATIONS) {
          if (mwm_hints.decorations & MWM_DECOR_ALL)
            window->decorated = ~mwm_hints.decorations & MWM_DECOR_TITLE;
          else
            window->decorated = mwm_hints.decorations & MWM_DECOR_TITLE;
        }
      }
    }

    if (!window->aura_surface)
      return;

    zaura_surface_set_frame(window->aura_surface,
                            window->decorated ? ZAURA_SURFACE_FRAME_TYPE_NORMAL
                            : window->depth == 32
                                ? ZAURA_SURFACE_FRAME_TYPE_NONE
                                : ZAURA_SURFACE_FRAME_TYPE_SHADOW);
  } else if (event->atom == ctx->atoms[ATOM_GTK_THEME_VARIANT].value) {
    struct sl_window* window;
    uint32_t frame_color;

    window = sl_lookup_window(ctx, event->window);
    if (!window)
      return;

    window->dark_frame = 0;

    if (event->state != XCB_PROPERTY_DELETE) {
      xcb_get_property_reply_t* reply = xcb_get_property_reply(
          ctx->connection,
          xcb_get_property(ctx->connection, 0, window->id,
                           ctx->atoms[ATOM_GTK_THEME_VARIANT].value,
                           XCB_ATOM_ANY, 0, 2048),
          NULL);
      if (reply) {
        if (xcb_get_property_value_length(reply) >= 4)
          window->dark_frame = !strcmp(
              static_cast<char*>(xcb_get_property_value(reply)), "dark");
        free(reply);
      }
    }

    if (!window->aura_surface)
      return;

    frame_color = window->dark_frame ? ctx->dark_frame_color : ctx->frame_color;
    zaura_surface_set_frame_colors(window->aura_surface, frame_color,
                                   frame_color);
  } else if (event->atom ==
             ctx->atoms[ATOM_XWAYLAND_RANDR_EMU_MONITOR_RECTS].value) {
    TRACE_EVENT("x11wm",
                "XCB_PROPERTY_NOTIFY: _XWAYLAND_RANDR_EMU_MONITOR_RECTS",
                [&](perfetto::EventContext p) {
                  xcb_get_property_cookie_t cookie = xcb_get_property(
                      ctx->connection, 0, event->window,
                      ctx->atoms[ATOM_XWAYLAND_RANDR_EMU_MONITOR_RECTS].value,
                      XCB_ATOM_ANY, 0, 2048);

                  perfetto_annotate_window(ctx, p, "window", event->window);

                  xcb_get_property_reply_t* reply =
                      xcb_get_property_reply(ctx->connection, cookie, NULL);
                  perfetto_annotate_cardinal_list(p, "value", reply);
                  free(reply);
                });
  } else if (event->atom == ctx->atoms[ATOM_WL_SELECTION].value) {
    if (event->window == ctx->selection_window &&
        event->state == XCB_PROPERTY_NEW_VALUE &&
        ctx->selection_incremental_transfer) {
      xcb_get_property_reply_t* reply = xcb_get_property_reply(
          ctx->connection,
          xcb_get_property(ctx->connection, 0, ctx->selection_window,
                           ctx->atoms[ATOM_WL_SELECTION].value,
                           XCB_GET_PROPERTY_TYPE_ANY, 0, 0x1fffffff),
          NULL);

      if (!reply)
        return;

      if (xcb_get_property_value_length(reply) > 0) {
        sl_write_selection_property(ctx, reply);
      } else {
        assert(!ctx->selection_send_event_source);
        close(ctx->selection_data_source_send_fd);
        ctx->selection_data_source_send_fd = -1;
        free(reply);

        sl_process_data_source_send_pending_list(ctx);
      }
    }
  } else if (event->atom == ctx->selection_request.property) {
    if (event->window == ctx->selection_request.requestor &&
        event->state == XCB_PROPERTY_DELETE &&
        ctx->selection_incremental_transfer) {
      int data_size = ctx->selection_data.size;

      ctx->selection_data_ack_pending = 0;

      // Handle the case when there's more data to be received.
      if (ctx->selection_data_offer_receive_fd >= 0) {
        // Avoid sending empty data until transfer is complete.
        if (data_size)
          sl_send_selection_data(ctx);

        if (!ctx->selection_event_source) {
          ctx->selection_event_source.reset(wl_event_loop_add_fd(
              wl_display_get_event_loop(ctx->host_display),
              ctx->selection_data_offer_receive_fd, WL_EVENT_READABLE,
              sl_handle_selection_fd_readable, ctx));
        }
        return;
      }

      sl_send_selection_data(ctx);

      // Release data if transfer is complete.
      if (!data_size) {
        ctx->selection_request.requestor = XCB_NONE;
        wl_array_release(&ctx->selection_data);
      }
    }
  }
}

static void sl_internal_data_source_target(void* data,
                                           struct wl_data_source* data_source,
                                           const char* mime_type) {}

static void sl_internal_data_source_send(void* data,
                                         struct wl_data_source* data_source,
                                         const char* mime_type,
                                         int32_t fd) {
  TRACE_EVENT("other", "sl_internal_data_source_send");
  struct sl_data_source* host = static_cast<sl_data_source*>(data);
  struct sl_context* ctx = host->ctx;

  xcb_intern_atom_cookie_t cookie =
      xcb_intern_atom(ctx->connection, false, strlen(mime_type), mime_type);

  if (ctx->selection_data_source_send_fd < 0) {
    sl_begin_data_source_send(ctx, fd, cookie, host);
  } else {
    struct sl_data_source_send_request* request =
        static_cast<sl_data_source_send_request*>(
            malloc(sizeof(struct sl_data_source_send_request)));

    request->fd = fd;
    request->cookie = cookie;
    request->data_source = host;
    wl_list_insert(&ctx->selection_data_source_send_pending, &request->link);
  }
}

static void sl_internal_data_source_cancelled(
    void* data, struct wl_data_source* data_source) {
  TRACE_EVENT("other", "sl_internal_data_source_cancelled");
  struct sl_data_source* host = static_cast<sl_data_source*>(data);

  if (host->ctx->selection_data_source == host)
    host->ctx->selection_data_source = NULL;

  wl_data_source_destroy(data_source);
}

static const struct wl_data_source_listener sl_internal_data_source_listener = {
    sl_internal_data_source_target, sl_internal_data_source_send,
    sl_internal_data_source_cancelled};

char* sl_copy_atom_name(xcb_get_atom_name_reply_t* reply) {
  // The string produced by xcb_get_atom_name_name isn't null terminated, so we
  // have to copy |name_len| bytes into a new buffer and add the null character
  // ourselves.
  char* name_start = xcb_get_atom_name_name(reply);
  int name_len = xcb_get_atom_name_name_length(reply);
  char* name = static_cast<char*>(malloc(name_len + 1));
  memcpy(name, name_start, name_len);
  name[name_len] = '\0';
  return name;
}

static void sl_get_selection_targets(struct sl_context* ctx) {
  TRACE_EVENT("other", "sl_get_selection_targets");
  struct sl_data_source* data_source = NULL;
  xcb_get_property_reply_t* reply;
  xcb_atom_t* value;
  uint32_t i;

  reply = xcb_get_property_reply(
      ctx->connection,
      xcb_get_property(ctx->connection, 1, ctx->selection_window,
                       ctx->atoms[ATOM_WL_SELECTION].value,
                       XCB_GET_PROPERTY_TYPE_ANY, 0, DEFAULT_BUFFER_SIZE),
      NULL);
  if (!reply)
    return;

  if (reply->type != XCB_ATOM_ATOM) {
    free(reply);
    return;
  }

  if (ctx->data_device_manager) {
    data_source = static_cast<sl_data_source*>(malloc(sizeof(*data_source)));
    assert(data_source);

    data_source->ctx = ctx;
    data_source->internal = wl_data_device_manager_create_data_source(
        ctx->data_device_manager->internal);
    wl_data_source_add_listener(data_source->internal,
                                &sl_internal_data_source_listener, data_source);

    value = static_cast<xcb_atom_t*>(xcb_get_property_value(reply));

    // We need to convert all of the offered target types from X11 atoms to
    // strings (i.e. getting the names of the atoms). Each conversion requires a
    // round trip to the X server, but none of the requests depend on each
    // other. Therefore, we can speed things up by sending out all the requests
    // as a batch with xcb_get_atom_name, and then read all the replies as a
    // batch with xcb_get_atom_name_reply.
    xcb_get_atom_name_cookie_t* atom_name_cookies =
        static_cast<xcb_get_atom_name_cookie_t*>(
            malloc(sizeof(xcb_get_atom_name_cookie_t) * reply->value_len));
    for (i = 0; i < reply->value_len; i++) {
      atom_name_cookies[i] = xcb_get_atom_name(ctx->connection, value[i]);
    }
    for (i = 0; i < reply->value_len; i++) {
      xcb_get_atom_name_reply_t* atom_name_reply =
          xcb_get_atom_name_reply(ctx->connection, atom_name_cookies[i], NULL);
      if (atom_name_reply) {
        char* name = sl_copy_atom_name(atom_name_reply);
        wl_data_source_offer(data_source->internal, name);
        free(atom_name_reply);
        free(name);
      }
    }
    free(atom_name_cookies);

    if (ctx->selection_data_device && ctx->default_seat) {
      wl_data_device_set_selection(ctx->selection_data_device,
                                   data_source->internal,
                                   ctx->default_seat->seat->last_serial);
    }

    if (ctx->selection_data_source) {
      wl_data_source_destroy(ctx->selection_data_source->internal);
      free(ctx->selection_data_source);
    }
    ctx->selection_data_source = data_source;
  }

  free(reply);
}

static void sl_get_selection_data(struct sl_context* ctx) {
  TRACE_EVENT("other", "sl_get_selection_data");
  xcb_get_property_reply_t* reply = xcb_get_property_reply(
      ctx->connection,
      xcb_get_property(ctx->connection, 1, ctx->selection_window,
                       ctx->atoms[ATOM_WL_SELECTION].value,
                       XCB_GET_PROPERTY_TYPE_ANY, 0, 0x1fffffff),
      NULL);
  if (!reply)
    return;

  if (reply->type == ctx->atoms[ATOM_INCR].value) {
    ctx->selection_incremental_transfer = 1;
    free(reply);
  } else {
    ctx->selection_incremental_transfer = 0;
    sl_write_selection_property(ctx, reply);
  }
}

static void sl_handle_selection_notify(struct sl_context* ctx,
                                       xcb_selection_notify_event_t* event) {
  if (event->property == XCB_ATOM_NONE)
    return;

  if (event->target == ctx->atoms[ATOM_TARGETS].value)
    sl_get_selection_targets(ctx);
  else
    sl_get_selection_data(ctx);
}

static void sl_send_targets(struct sl_context* ctx) {
  xcb_change_property(
      ctx->connection, XCB_PROP_MODE_REPLACE, ctx->selection_request.requestor,
      ctx->selection_request.property, XCB_ATOM_ATOM, 32,
      ctx->selection_data_offer->atoms.size / sizeof(xcb_atom_t),
      ctx->selection_data_offer->atoms.data);

  sl_send_selection_notify(ctx, ctx->selection_request.property);
}

static void sl_send_timestamp(struct sl_context* ctx) {
  xcb_change_property(ctx->connection, XCB_PROP_MODE_REPLACE,
                      ctx->selection_request.requestor,
                      ctx->selection_request.property, XCB_ATOM_INTEGER, 32, 1,
                      &ctx->selection_timestamp);

  sl_send_selection_notify(ctx, ctx->selection_request.property);
}

static void sl_send_data(struct sl_context* ctx, xcb_atom_t data_type) {
  TRACE_EVENT("other", "sl_send_data");
  int rv, fd_to_receive, fd_to_wayland;

  if (!ctx->selection_data_offer) {
    sl_send_selection_notify(ctx, XCB_ATOM_NONE);
    return;
  }

  if (ctx->selection_event_source) {
    fprintf(stderr, "error: selection transfer already pending\n");
    sl_send_selection_notify(ctx, XCB_ATOM_NONE);
    return;
  }

  ctx->selection_data_type = data_type;

  // We will need the name of this atom later to tell the wayland server what
  // type of data to send us, so start the request now.
  xcb_get_atom_name_cookie_t atom_name_cookie =
      xcb_get_atom_name(ctx->connection, data_type);

  wl_array_init(&ctx->selection_data);
  ctx->selection_data_ack_pending = 0;

  if (ctx->channel == NULL) {
    // Running in noop mode, without virtualization.
    int p[2];

    rv = pipe2(p, O_CLOEXEC | O_NONBLOCK);
    errno_assert(!rv);

    fd_to_receive = p[0];
    fd_to_wayland = p[1];
  } else {
    int pipe_fd;
    rv = ctx->channel->create_pipe(pipe_fd);
    if (rv) {
      fprintf(stderr, "error: failed to create virtwl pipe: %s\n",
              strerror(-rv));
      sl_send_selection_notify(ctx, XCB_ATOM_NONE);
      return;
    }

    fd_to_receive = pipe_fd;
    fd_to_wayland = pipe_fd;
  }

  xcb_get_atom_name_reply_t* atom_name_reply =
      xcb_get_atom_name_reply(ctx->connection, atom_name_cookie, NULL);
  if (atom_name_reply) {
    // If we got the atom name, then send the request to wayland and add our end
    // of the pipe to the wayland event loop.
    ctx->selection_data_offer_receive_fd = fd_to_receive;
    char* name = sl_copy_atom_name(atom_name_reply);
    wl_data_offer_receive(ctx->selection_data_offer->internal, name,
                          fd_to_wayland);
    free(atom_name_reply);
    free(name);

    ctx->selection_event_source.reset(wl_event_loop_add_fd(
        wl_display_get_event_loop(ctx->host_display),
        ctx->selection_data_offer_receive_fd, WL_EVENT_READABLE,
        sl_handle_selection_fd_readable, ctx));
  } else {
    // If getting the atom name failed, notify the requestor that there won't be
    // any data, and close our end of the pipe.
    close(fd_to_receive);
    sl_send_selection_notify(ctx, XCB_ATOM_NONE);
  }

  // Close the wayland end of the pipe, now that it's either been sent or not
  // going to be sent. The VIRTWL driver uses the same fd for both ends of the
  // pipe, so don't close the fd if both ends are the same.
  if (fd_to_receive != fd_to_wayland)
    close(fd_to_wayland);
}

static void sl_handle_selection_request(struct sl_context* ctx,
                                        xcb_selection_request_event_t* event) {
  ctx->selection_request = *event;
  ctx->selection_incremental_transfer = 0;

  if (event->selection == ctx->atoms[ATOM_CLIPBOARD_MANAGER].value) {
    sl_send_selection_notify(ctx, ctx->selection_request.property);
    return;
  }

  if (event->target == ctx->atoms[ATOM_TARGETS].value) {
    sl_send_targets(ctx);
  } else if (event->target == ctx->atoms[ATOM_TIMESTAMP].value) {
    sl_send_timestamp(ctx);
  } else {
    int success = 0;
    xcb_atom_t* atom;
    sl_array_for_each(atom, &ctx->selection_data_offer->atoms) {
      if (event->target == *atom) {
        success = 1;
        sl_send_data(ctx, *atom);
        break;
      }
    }
    if (!success) {
      sl_send_selection_notify(ctx, XCB_ATOM_NONE);
    }
  }
}

static void sl_handle_xfixes_selection_notify(
    struct sl_context* ctx, xcb_xfixes_selection_notify_event_t* event) {
  if (event->selection != ctx->atoms[ATOM_CLIPBOARD].value)
    return;

  if (event->owner == XCB_WINDOW_NONE) {
    // If client selection is gone. Set NULL selection for each seat.
    if (ctx->selection_owner != ctx->selection_window) {
      if (ctx->selection_data_device && ctx->default_seat) {
        wl_data_device_set_selection(ctx->selection_data_device, NULL,
                                     ctx->default_seat->seat->last_serial);
      }
    }
    ctx->selection_owner = XCB_WINDOW_NONE;
    return;
  }

  ctx->selection_owner = event->owner;

  // Save timestamp if it's our selection.
  if (event->owner == ctx->selection_window) {
    ctx->selection_timestamp = event->timestamp;
    return;
  }

  ctx->selection_incremental_transfer = 0;
  xcb_convert_selection(ctx->connection, ctx->selection_window,
                        ctx->atoms[ATOM_CLIPBOARD].value,
                        ctx->atoms[ATOM_TARGETS].value,
                        ctx->atoms[ATOM_WL_SELECTION].value, event->timestamp);
}

static int sl_handle_x_connection_event(int fd, uint32_t mask, void* data) {
  TRACE_EVENT("other", "sl_handle_x_connection_event");
  struct sl_context* ctx = (struct sl_context*)data;
  xcb_generic_event_t* event;
  uint32_t count = 0;

  if ((mask & WL_EVENT_HANGUP) || (mask & WL_EVENT_ERROR)) {
    fprintf(stderr, "Got error or hangup (mask %d) on X connection, exiting\n",
            mask);
    exit(EXIT_SUCCESS);
  }

  while ((event = xcb_poll_for_event(ctx->connection))) {
    switch (event->response_type & ~SEND_EVENT_MASK) {
      case XCB_CREATE_NOTIFY:
        sl_handle_create_notify(
            ctx, reinterpret_cast<xcb_create_notify_event_t*>(event));
        break;
      case XCB_DESTROY_NOTIFY:
        sl_handle_destroy_notify(
            ctx, reinterpret_cast<xcb_destroy_notify_event_t*>(event));
        break;
      case XCB_REPARENT_NOTIFY:
        sl_handle_reparent_notify(
            ctx, reinterpret_cast<xcb_reparent_notify_event_t*>(event));
        break;
      case XCB_MAP_REQUEST:
        sl_handle_map_request(
            ctx, reinterpret_cast<xcb_map_request_event_t*>(event));
        break;
      case XCB_MAP_NOTIFY:
        sl_handle_map_notify(ctx,
                             reinterpret_cast<xcb_map_notify_event_t*>(event));
        break;
      case XCB_UNMAP_NOTIFY:
        sl_handle_unmap_notify(
            ctx, reinterpret_cast<xcb_unmap_notify_event_t*>(event));
        break;
      case XCB_CONFIGURE_REQUEST:
        sl_handle_configure_request(
            ctx, reinterpret_cast<xcb_configure_request_event_t*>(event));
        break;
      case XCB_CONFIGURE_NOTIFY:
        sl_handle_configure_notify(
            ctx, reinterpret_cast<xcb_configure_notify_event_t*>(event));
        break;
      case XCB_CLIENT_MESSAGE:
        sl_handle_client_message(
            ctx, reinterpret_cast<xcb_client_message_event_t*>(event));
        break;
      case XCB_FOCUS_IN:
        sl_handle_focus_in(ctx, reinterpret_cast<xcb_focus_in_event_t*>(event));
        break;
      case XCB_FOCUS_OUT:
        sl_handle_focus_out(ctx,
                            reinterpret_cast<xcb_focus_out_event_t*>(event));
        break;
      case XCB_PROPERTY_NOTIFY:
        sl_handle_property_notify(
            ctx, reinterpret_cast<xcb_property_notify_event_t*>(event));
        break;
      case XCB_SELECTION_NOTIFY:
        sl_handle_selection_notify(
            ctx, reinterpret_cast<xcb_selection_notify_event_t*>(event));
        break;
      case XCB_SELECTION_REQUEST:
        sl_handle_selection_request(
            ctx, reinterpret_cast<xcb_selection_request_event_t*>(event));
        break;
    }

    switch (event->response_type - ctx->xfixes_extension->first_event) {
      case XCB_XFIXES_SELECTION_NOTIFY:
        sl_handle_xfixes_selection_notify(
            ctx, reinterpret_cast<xcb_xfixes_selection_notify_event_t*>(event));
        break;
    }

    // Xshape specific events extend the normal event numbers
    // The first event id is retrieved when querying for xshape
    // extension information. This can be used to determine
    // if the event that is received is Xshape specific.
    if (ctx->enable_xshape) {
      uint8_t xshape_event_id =
          event->response_type - ctx->xshape_extension->first_event;
      switch (xshape_event_id) {
        case XCB_SHAPE_NOTIFY:
          sl_handle_shape_notify(
              ctx, reinterpret_cast<xcb_shape_notify_event_t*>(event));
          break;
      }
    }

    free(event);
    ++count;
  }

  if ((mask & ~WL_EVENT_WRITABLE) == 0)
    xcb_flush(ctx->connection);

  return count;
}

static void sl_set_supported(struct sl_context* ctx) {
  const xcb_atom_t supported_atoms[] = {
      ctx->atoms[ATOM_NET_ACTIVE_WINDOW].value,
      ctx->atoms[ATOM_NET_WM_MOVERESIZE].value,
      ctx->atoms[ATOM_NET_WM_NAME].value,
      ctx->atoms[ATOM_NET_WM_STATE].value,
      ctx->atoms[ATOM_NET_WM_STATE_FULLSCREEN].value,
      ctx->atoms[ATOM_NET_WM_STATE_MAXIMIZED_VERT].value,
      ctx->atoms[ATOM_NET_WM_STATE_MAXIMIZED_HORZ].value,
      ctx->atoms[ATOM_NET_WM_STATE_FOCUSED].value,
      // TODO(hollingum): STATE_MODAL and CLIENT_LIST, based on what wlroots
      // has.
  };

  xcb_change_property(ctx->connection, XCB_PROP_MODE_REPLACE, ctx->screen->root,
                      ctx->atoms[ATOM_NET_SUPPORTED].value, XCB_ATOM_ATOM, 32,
                      sizeof(supported_atoms) / sizeof(xcb_atom_t),
                      supported_atoms);
}

// The window manager is responsible for setting the default cursor on the root
// window, which will be used by applications that do not try to set their own
// cursor. If we do not do this, the cursor will be invisible, see b/204724669
// for details.
static void sl_initialize_cursor(struct sl_context* ctx) {
  xcb_generic_error_t* err;
  xcb_void_cookie_t cookie;

  // Load the "cursor" font, which is a built-in set of fonts, documented at
  // https://tronche.com/gui/x/xlib/appendix/b/.
  xcb_font_t font_id = xcb_generate_id(ctx->connection);
  cookie = xcb_open_font_checked(ctx->connection, font_id, strlen("cursor"),
                                 "cursor");
  err = xcb_request_check(ctx->connection, cookie);
  assert(!err);

  // Create the standard "left ptr" cursor. The below call is a bit technical,
  // but it means:
  //  - font_id appears twice because we use a mask (background) whose font is
  //    the same as the source.
  //  - the mask is the source + 1, because the inbuilt cursor font has
  //    even-numbered foreground glyphs and odd-numbered backgrounds.
  //  - The numbers are 16-bit RGB for the foreground and background, so this
  //    has a black foreground and a white background.
  constexpr int left_ptr_cursor_id = 68;
  xcb_cursor_t cursor_id = xcb_generate_id(ctx->connection);
  cookie = xcb_create_glyph_cursor_checked(
      ctx->connection, cursor_id, font_id, font_id, left_ptr_cursor_id,
      left_ptr_cursor_id + 1, 0, 0, 0, 65535, 65535, 65535);
  err = xcb_request_check(ctx->connection, cookie);
  assert(!err);

  // Set the cursor for the root window.
  cookie = xcb_change_window_attributes_checked(
      ctx->connection, ctx->screen->root, XCB_CW_CURSOR, &cursor_id);
  err = xcb_request_check(ctx->connection, cookie);
  assert(!err);

  // Free the cursor and the fonts, since we no-longer need them.
  xcb_free_cursor(ctx->connection, cursor_id);
  cookie = xcb_close_font_checked(ctx->connection, font_id);
  err = xcb_request_check(ctx->connection, cookie);
  assert(!err);
}

static void sl_connect(struct sl_context* ctx) {
  TRACE_EVENT("other", "sl_connect");
  const char wm_name[] = "Sommelier";
  const xcb_setup_t* setup;
  xcb_screen_iterator_t screen_iterator;
  uint32_t values[1];
  xcb_void_cookie_t change_attributes_cookie, redirect_subwindows_cookie;
  xcb_generic_error_t* error;
  xcb_intern_atom_reply_t* atom_reply;
  xcb_depth_iterator_t depth_iterator;
  xcb_xfixes_query_version_reply_t* xfixes_query_version_reply;
  xcb_shape_query_version_reply_t* xshape_query_version_reply;
  const xcb_query_extension_reply_t* composite_extension;
  unsigned i;

  ctx->connection = xcb_connect_to_fd(ctx->wm_fd, NULL);
  assert(!xcb_connection_has_error(ctx->connection));

  xcb_prefetch_extension_data(ctx->connection, &xcb_xfixes_id);
  xcb_prefetch_extension_data(ctx->connection, &xcb_composite_id);

  // Send requests to fetch/create ("intern") all the atoms we'll need later.
  for (i = 0; i < ARRAY_SIZE(ctx->atoms); ++i) {
    const char* name = ctx->atoms[i].name;
    ctx->atoms[i].cookie =
        xcb_intern_atom(ctx->connection, 0, strlen(name), name);
  }
  xcb_intern_atom_cookie_t app_id_atom_cookie;
  if (ctx->application_id_property_name) {
    app_id_atom_cookie = xcb_intern_atom(
        ctx->connection, 0, strlen(ctx->application_id_property_name),
        ctx->application_id_property_name);
  }

  setup = xcb_get_setup(ctx->connection);
  screen_iterator = xcb_setup_roots_iterator(setup);
  ctx->screen = screen_iterator.data;

  // Select for substructure redirect.
  values[0] = XCB_EVENT_MASK_STRUCTURE_NOTIFY |
              XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY |
              XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT;
  change_attributes_cookie = xcb_change_window_attributes(
      ctx->connection, ctx->screen->root, XCB_CW_EVENT_MASK, values);

  ctx->connection_event_source.reset(wl_event_loop_add_fd(
      wl_display_get_event_loop(ctx->host_display),
      xcb_get_file_descriptor(ctx->connection), WL_EVENT_READABLE,
      &sl_handle_x_connection_event, ctx));

  ctx->xfixes_extension =
      xcb_get_extension_data(ctx->connection, &xcb_xfixes_id);
  assert(ctx->xfixes_extension->present);

  xfixes_query_version_reply = xcb_xfixes_query_version_reply(
      ctx->connection,
      xcb_xfixes_query_version(ctx->connection, XCB_XFIXES_MAJOR_VERSION,
                               XCB_XFIXES_MINOR_VERSION),
      NULL);
  assert(xfixes_query_version_reply);
  assert(xfixes_query_version_reply->major_version >= 5);
  free(xfixes_query_version_reply);

  composite_extension =
      xcb_get_extension_data(ctx->connection, &xcb_composite_id);
  assert(composite_extension->present);
  UNUSED(composite_extension);

  if (ctx->enable_xshape) {
    xcb_prefetch_extension_data(ctx->connection, &xcb_shape_id);

    ctx->xshape_extension =
        xcb_get_extension_data(ctx->connection, &xcb_shape_id);

    xshape_query_version_reply = xcb_shape_query_version_reply(
        ctx->connection, xcb_shape_query_version(ctx->connection), NULL);

    assert(xshape_query_version_reply);
    assert(xshape_query_version_reply->major_version >=
           XCB_SHAPE_MAJOR_VERSION);
    assert(xshape_query_version_reply->minor_version >=
           XCB_SHAPE_MINOR_VERSION);
    free(xshape_query_version_reply);
    xshape_query_version_reply = NULL;
  }

  redirect_subwindows_cookie = xcb_composite_redirect_subwindows_checked(
      ctx->connection, ctx->screen->root, XCB_COMPOSITE_REDIRECT_MANUAL);

  // Another window manager should not be running.
  error = xcb_request_check(ctx->connection, change_attributes_cookie);
  assert(!error);

  // Redirecting subwindows of root for compositing should have succeeded.
  error = xcb_request_check(ctx->connection, redirect_subwindows_cookie);
  assert(!error);

  ctx->window = xcb_generate_id(ctx->connection);
  xcb_create_window(ctx->connection, 0, ctx->window, ctx->screen->root, 0, 0, 1,
                    1, 0, XCB_WINDOW_CLASS_INPUT_ONLY, XCB_COPY_FROM_PARENT, 0,
                    NULL);

  // Wait on results for all the atom intern requests we sent above.
  for (i = 0; i < ARRAY_SIZE(ctx->atoms); ++i) {
    atom_reply =
        xcb_intern_atom_reply(ctx->connection, ctx->atoms[i].cookie, &error);
    assert(!error);
    ctx->atoms[i].value = atom_reply->atom;
    free(atom_reply);
  }
  if (ctx->application_id_property_name) {
    atom_reply =
        xcb_intern_atom_reply(ctx->connection, app_id_atom_cookie, &error);
    assert(!error);
    ctx->application_id_property_atom = atom_reply->atom;
    free(atom_reply);
  }

  depth_iterator = xcb_screen_allowed_depths_iterator(ctx->screen);
  while (depth_iterator.rem > 0) {
    int depth = depth_iterator.data->depth;
    if (depth == ctx->screen->root_depth) {
      ctx->visual_ids[depth] = ctx->screen->root_visual;
      ctx->colormaps[depth] = ctx->screen->default_colormap;
    } else {
      xcb_visualtype_iterator_t visualtype_iterator =
          xcb_depth_visuals_iterator(depth_iterator.data);

      ctx->visual_ids[depth] = visualtype_iterator.data->visual_id;
      ctx->colormaps[depth] = xcb_generate_id(ctx->connection);
      xcb_create_colormap(ctx->connection, XCB_COLORMAP_ALLOC_NONE,
                          ctx->colormaps[depth], ctx->screen->root,
                          ctx->visual_ids[depth]);
    }
    xcb_depth_next(&depth_iterator);
  }
  assert(ctx->visual_ids[ctx->screen->root_depth]);

  if (ctx->clipboard_manager) {
    values[0] = XCB_EVENT_MASK_PROPERTY_CHANGE;
    ctx->selection_window = xcb_generate_id(ctx->connection);
    xcb_create_window(ctx->connection, XCB_COPY_FROM_PARENT,
                      ctx->selection_window, ctx->screen->root, 0, 0, 1, 1, 0,
                      XCB_WINDOW_CLASS_INPUT_OUTPUT, ctx->screen->root_visual,
                      XCB_CW_EVENT_MASK, values);
    xcb_set_selection_owner(ctx->connection, ctx->selection_window,
                            ctx->atoms[ATOM_CLIPBOARD_MANAGER].value,
                            XCB_CURRENT_TIME);
    xcb_xfixes_select_selection_input(
        ctx->connection, ctx->selection_window,
        ctx->atoms[ATOM_CLIPBOARD].value,
        XCB_XFIXES_SELECTION_EVENT_MASK_SET_SELECTION_OWNER |
            XCB_XFIXES_SELECTION_EVENT_MASK_SELECTION_WINDOW_DESTROY |
            XCB_XFIXES_SELECTION_EVENT_MASK_SELECTION_CLIENT_CLOSE);
    sl_set_selection(ctx, NULL);
  }

  xcb_change_property(ctx->connection, XCB_PROP_MODE_REPLACE, ctx->window,
                      ctx->atoms[ATOM_NET_SUPPORTING_WM_CHECK].value,
                      XCB_ATOM_WINDOW, 32, 1, &ctx->window);
  xcb_change_property(ctx->connection, XCB_PROP_MODE_REPLACE, ctx->window,
                      ctx->atoms[ATOM_NET_WM_NAME].value,
                      ctx->atoms[ATOM_UTF8_STRING].value, 8, strlen(wm_name),
                      wm_name);
  xcb_change_property(ctx->connection, XCB_PROP_MODE_REPLACE, ctx->screen->root,
                      ctx->atoms[ATOM_NET_SUPPORTING_WM_CHECK].value,
                      XCB_ATOM_WINDOW, 32, 1, &ctx->window);
  sl_set_supported(ctx);
  xcb_set_selection_owner(ctx->connection, ctx->window,
                          ctx->atoms[ATOM_WM_S0].value, XCB_CURRENT_TIME);

  xcb_set_input_focus(ctx->connection, XCB_INPUT_FOCUS_NONE, XCB_NONE,
                      XCB_CURRENT_TIME);
  xcb_flush(ctx->connection);

  sl_initialize_cursor(ctx);
}

static void sl_sd_notify(const char* state) {
  const char* socket_name;
  struct msghdr msghdr;
  struct iovec iovec;
  struct sockaddr_un addr;
  int fd;
  int rv;

  socket_name = getenv("NOTIFY_SOCKET");
  assert(socket_name);

  fd = socket(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0);
  errno_assert(fd >= 0);

  memset(&addr, 0, sizeof(addr));
  addr.sun_family = AF_UNIX;
  strncpy(addr.sun_path, socket_name, sizeof(addr.sun_path));

  memset(&iovec, 0, sizeof(iovec));
  // iovec is just going to be used to send data as part of a const msghdr.
  iovec.iov_base = const_cast<char*>(state);
  iovec.iov_len = strlen(state);

  memset(&msghdr, 0, sizeof(msghdr));
  msghdr.msg_name = &addr;
  msghdr.msg_namelen =
      offsetof(struct sockaddr_un, sun_path) + strlen(socket_name);
  msghdr.msg_iov = &iovec;
  msghdr.msg_iovlen = 1;

  rv = sendmsg(fd, &msghdr, MSG_NOSIGNAL);
  errno_assert(rv != -1);
}

static int sl_handle_sigchld(int signal_number, void* data) {
  struct sl_context* ctx = (struct sl_context*)data;
  int status;
  pid_t pid;

  while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
    if (pid == ctx->child_pid) {
      ctx->child_pid = -1;
      if (WIFEXITED(status) && WEXITSTATUS(status)) {
        fprintf(stderr, "Child exited with status: %d\n", WEXITSTATUS(status));
      }
      if (ctx->exit_with_child) {
        if (ctx->xwayland_pid >= 0)
          kill(ctx->xwayland_pid, SIGTERM);
      } else {
        // Notify systemd that we are ready to accept connections now that
        // child process has finished running and all environment is ready.
        if (ctx->sd_notify)
          sl_sd_notify(ctx->sd_notify);
      }
    } else if (pid == ctx->xwayland_pid) {
      ctx->xwayland_pid = -1;
      if (WIFEXITED(status) && WEXITSTATUS(status)) {
        fprintf(stderr, "Xwayland exited with status: %d\n",
                WEXITSTATUS(status));
        exit(WEXITSTATUS(status));
      }
    }
  }

  return 1;
}

static int sl_handle_sigusr1(int signal_number, void* data) {
  struct sl_context* ctx = (struct sl_context*)data;
  fprintf(stderr, "dumping trace %s\n", ctx->trace_filename);
  dump_trace(ctx->trace_filename);
  if (ctx->timing != NULL) {
    ctx->timing->OutputLog();
  }
  return 1;
}

static void sl_execvp(const char* file,
                      char* const argv[],
                      int wayland_socked_fd) {
  if (wayland_socked_fd >= 0) {
    int fd;
    fd = dup(wayland_socked_fd);
    putenv(sl_xasprintf("WAYLAND_SOCKET=%d", fd));
  }

  setenv("SOMMELIER_VERSION", SOMMELIER_VERSION, 1);

  execvp(file, argv);
  perror(file);
}

static void sl_calculate_scale_for_xwayland(struct sl_context* ctx) {
  struct sl_host_output* output;
  double default_scale_factor = 1.0;
  double scale = ctx->desired_scale;

  if (!ctx->use_direct_scale) {
    // Find internal output and determine preferred scale factor.
    wl_list_for_each(output, &ctx->host_outputs, link) {
      if (output->internal) {
        double preferred_scale =
            sl_output_aura_scale_factor_to_double(output->preferred_scale);

        if (ctx->aura_shell) {
          double device_scale_factor = sl_output_aura_scale_factor_to_double(
              output->device_scale_factor);

          default_scale_factor = device_scale_factor * preferred_scale;
        }
        break;
      }
    }
    // We use the default scale factor multiplied by desired scale set by the
    // user. This gives us HiDPI support by default but the user can still
    // adjust it if higher or lower density is preferred.
    scale = ctx->desired_scale * default_scale_factor;

    // Round to integer scale if wp_viewporter interface is not present.
    if (!ctx->viewporter)
      scale = round(scale);
  }

  // Clamp and set scale.
  ctx->scale = MIN(MAX_SCALE, MAX(MIN_SCALE, scale));

  // Scale affects output state. Send updated output state to xwayland.
  wl_list_for_each(output, &ctx->host_outputs, link)
      sl_output_send_host_output_state(output);
}

// Extra connections are made to XWayland-hosting instances for IME support.
static void sl_extra_client_created_notify(struct wl_listener* listener,
                                           void* data) {
  sl_context* ctx =
      wl_container_of(listener, ctx, extra_client_created_listener);
  wl_client* client = static_cast<wl_client*>(data);

  sl_set_display_implementation(ctx, client);
}

static int sl_handle_display_ready_event(int fd, uint32_t mask, void* data) {
  TRACE_EVENT("surface", "sl_handle_display_ready_event");
  struct sl_context* ctx = (struct sl_context*)data;
  char display_name[9];
  int bytes_read = 0;
  pid_t pid;

  if (!(mask & WL_EVENT_READABLE)) {
    fprintf(stderr,
            "Got error or hangup on display ready connection"
            " (mask %d), exiting\n",
            mask);
    exit(EXIT_SUCCESS);
  }

  display_name[0] = ':';
  do {
    int bytes_left = sizeof(display_name) - bytes_read - 1;
    int bytes;

    if (!bytes_left)
      break;

    bytes = read(fd, &display_name[bytes_read + 1], bytes_left);
    if (!bytes)
      break;

    bytes_read += bytes;
  } while (display_name[bytes_read] != '\n');

  display_name[bytes_read] = '\0';
  setenv("DISPLAY", display_name, 1);

  sl_connect(ctx);

  ctx->display_ready_event_source.reset();
  close(fd);

  // Calculate scale now that the default scale factor is known. This also
  // happens to workaround an issue in Xwayland where an output update is
  // needed for DPI to be set correctly.
  sl_calculate_scale_for_xwayland(ctx);
  wl_display_flush_clients(ctx->host_display);

  // Open wayland socket so cros_im can provide IME support to X11 apps.
  // This depends on the display number, which is only available once Xwayland
  // initialization is complete (now), so we can't create this earlier to use
  // it for the wayland connection with Xwayland.
  char* socket_name = sl_xasprintf("DISPLAY-%s-wl", display_name);
  struct sockaddr_un addr;
  int lock_fd;
  int sock_fd;
  int rv = sl_open_wayland_socket(socket_name, &addr, &lock_fd, &sock_fd);
  if (rv >= 0) {
    wl_display_add_socket_fd(ctx->host_display, sock_fd);
    ctx->extra_client_created_listener.notify = sl_extra_client_created_notify;
    wl_display_add_client_created_listener(ctx->host_display,
                                           &ctx->extra_client_created_listener);
  } else {
    fprintf(stderr, "warning: unable to open wayland socket for cros_im.\n");
  }
  free(socket_name);

  putenv(sl_xasprintf("XCURSOR_SIZE=%d",
                      static_cast<int>(XCURSOR_SIZE_BASE * ctx->scale + 0.5)));

  pid = fork();
  errno_assert(pid >= 0);
  if (pid == 0) {
    // Set WAYLAND_DISPLAY to a value that is guaranteed to not point to a
    // valid wayland compositor socket name. Unsetting WAYLAND_DISPLAY is
    // insufficient as some clients may attempt to connect to wayland-0 as a
    // default fallback.
    setenv("WAYLAND_DISPLAY", ".", 1);
    sl_execvp(ctx->runprog[0], ctx->runprog, -1);
    _exit(EXIT_FAILURE);
  }

  ctx->child_pid = pid;

  return 1;
}

static void sl_sigchld_handler(int signal) {
  while (waitpid(-1, NULL, WNOHANG) > 0)
    continue;
}

static void sl_client_destroy_notify(struct wl_listener* listener, void* data) {
  exit(0);
}

// Break |str| into a sequence of zero or more nonempty arguments. No more
// than |argc| arguments will be added to |argv|. Returns the total number of
// argments found in |str|.
static int sl_parse_cmd_prefix(char* str, int argc, char const** argv) {
  char* s = str;
  int n = 0;
  int delim = 0;

  do {
    // Look for ending delimiter if |delim| is set.
    if (delim) {
      if (*s == delim) {
        delim = 0;
        *s = '\0';
      }
      ++s;
    } else {
      // Skip forward to first non-space character.
      while (*s == ' ' && *s != '\0')
        ++s;

      // Check for quote delimiter.
      if (*s == '"') {
        delim = '"';
        ++s;
      } else {
        delim = ' ';
      }

      // Add string to arguments if there's room.
      if (n < argc)
        argv[n] = s;

      ++n;
    }
  } while (*s != '\0');

  return n;
}

static void sl_print_usage() {
  printf(
      "usage: sommelier [options] [program] [args...]\n\n"
      "options:\n"
      "  -h, --help\t\t\tPrint this help\n"
      "  -X\t\t\t\tEnable X11 forwarding\n"
      "  --parent\t\t\tRun as parent and spawn child processes\n"
      "  --socket=SOCKET\t\tName of socket to listen on\n"
      "  --display=DISPLAY\t\tWayland display to connect to\n"
      "  --scale=SCALE\t\t\tScale factor for contents\n"
      "  --dpi=[DPI[,DPI...]]\t\tDPI buckets\n"
      "  --peer-cmd-prefix=PREFIX\tPeer process command line prefix\n"
      "  --accelerators=ACCELERATORS\tList of keyboard accelerators\n"
      "  --windowed_accelerators=ACCELERATORS\tList of keyboard accelerators\n"
      "\tonly while windowed\n"
      "  --application-id=ID\t\tForced application ID for all X11 windows\n"
      "  --vm-identifier=NAME\t\tName of the VM, used to identify X11 "
      "windows.\n"
      "\t\t\t\tIgnored if --application-id is set.\n"
      "  --application-id-x11-property=PROPERTY\n"
      "\tA cardinal window property used to identify X11 windows, as follows:\n"
      "\t  org.chromium.<vm-identifier>.xprop.<application-id-x11-property>\n"
      "\tIgnored if --application-id is set.\n"
      "  --x-display=DISPLAY\t\tX11 display to listen on\n"
      "  --xwayland-path=PATH\t\tPath to Xwayland executable\n"
      "  --xwayland-gl-driver-path=PATH\tPath to GL drivers for Xwayland\n"
      "  --xwayland-cmd-prefix=PREFIX\tXwayland command line prefix\n"
      "  --enable-xshape\t\tEnable X11 XShape extension support\n"
      "  --no-exit-with-child\t\tKeep process alive after child exists\n"
      "  --no-clipboard-manager\tDisable X11 clipboard manager\n"
      "  --frame-color=COLOR\t\tWindow frame color for X11 clients\n"
      "  --no-support-damage-buffer\t"
      "Disable wl_surface::damage_buffer support.\n"
      "  --force-drm-device=DEVICE\tDRM device to use\n"
      "  --glamor\t\t\tUse glamor to accelerate X11 clients\n"
      "  --timing-filename=PATH\tPath to timing output log\n"
      "  --direct-scale\t\tEnable direct scaling mode\n"
#ifdef PERFETTO_TRACING
      "  --trace-filename=PATH\t\tPath to Perfetto trace filename\n"
      "  --trace-system\t\tPerfetto trace to system daemon\n"
#endif
      "  --fullscreen-mode=MODE\tDefault fullscreen behavior (immersive,"
      " plain)\n"
      "  --noop-driver\t\tPass through to existing Wayland server"
      " without virtualization\n");
}

static const char* sl_arg_value(const char* arg) {
  const char* s = strchr(arg, '=');
  if (!s) {
    sl_print_usage();
    exit(EXIT_FAILURE);
  }
  return s + 1;
}

// Parse the list of accelerators that should be reserved by the
// compositor. Format is "|MODIFIERS|KEYSYM", where MODIFIERS is a
// list of modifier names (E.g. <Control><Alt>) and KEYSYM is an
// XKB key symbol name (E.g Delete).
// Sommelier will exit with EXIT_FAILURE if this returns false.
// TODO(b/237946069) Confirm accelerator handling works with i18n.
static bool sl_parse_accelerators(struct wl_list* accelerator_list,
                                  const char* accelerators) {
  if (accelerators) {
    uint32_t modifiers = 0;

    while (*accelerators) {
      if (*accelerators == ',') {
        accelerators++;
      } else if (*accelerators == '<') {
        if (strncmp(accelerators, "<Control>", 9) == 0) {
          modifiers |= CONTROL_MASK;
          accelerators += 9;
        } else if (strncmp(accelerators, "<Alt>", 5) == 0) {
          modifiers |= ALT_MASK;
          accelerators += 5;
        } else if (strncmp(accelerators, "<Shift>", 7) == 0) {
          modifiers |= SHIFT_MASK;
          accelerators += 7;
        } else {
          fprintf(stderr, "error: invalid modifier\n");
          return false;
        }
      } else {
        const char* end = strchrnul(accelerators, ',');
        char* name = strndup(accelerators, end - accelerators);

        struct sl_accelerator* accelerator =
            static_cast<sl_accelerator*>(malloc(sizeof(*accelerator)));
        accelerator->modifiers = modifiers;
        accelerator->symbol =
            xkb_keysym_from_name(name, XKB_KEYSYM_CASE_INSENSITIVE);
        if (accelerator->symbol == XKB_KEY_NoSymbol) {
          fprintf(stderr, "error: invalid key symbol\n");
          return false;
        }

        wl_list_insert(accelerator_list, &accelerator->link);

        modifiers = 0;
        accelerators = end;
        free(name);
      }
    }
  }
  return true;
}

// Takes the lock and then opens the socket for wayland clients to connect to.
// Returns a negative value on error. |addr|, |lock_fd| and |sock_fd| will be
// populated on success.
int sl_open_wayland_socket(const char* socket_name,
                           struct sockaddr_un* addr,
                           int* lock_fd,
                           int* sock_fd) {
  int rv;

  const char* runtime_dir = getenv("XDG_RUNTIME_DIR");
  if (!runtime_dir) {
    fprintf(stderr, "error: XDG_RUNTIME_DIR not set in the environment\n");
    return -1;
  }

  addr->sun_family = AF_LOCAL;
  snprintf(addr->sun_path, sizeof(addr->sun_path), "%s/%s", runtime_dir,
           socket_name);

  char* lock_addr = sl_xasprintf("%s%s", addr->sun_path, LOCK_SUFFIX);

  *lock_fd = open(lock_addr, O_CREAT | O_CLOEXEC,
                  (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP));
  errno_assert(*lock_fd >= 0);

  rv = flock(*lock_fd, LOCK_EX | LOCK_NB);
  if (rv < 0) {
    fprintf(stderr,
            "error: unable to lock %s, is another compositor running?\n",
            lock_addr);
    return rv;
  }
  free(lock_addr);

  struct stat sock_stat;
  rv = stat(addr->sun_path, &sock_stat);
  if (rv >= 0) {
    if (sock_stat.st_mode & (S_IWUSR | S_IWGRP))
      unlink(addr->sun_path);
  } else {
    errno_assert(errno == ENOENT);
  }

  *sock_fd = socket(PF_LOCAL, SOCK_STREAM, 0);
  errno_assert(*sock_fd >= 0);

  rv = bind(*sock_fd, (struct sockaddr*)addr,
            offsetof(struct sockaddr_un, sun_path) + strlen(addr->sun_path));
  errno_assert(rv >= 0);

  rv = listen(*sock_fd, 128);
  errno_assert(rv >= 0);

  return 0;
}

int sl_run_parent(int argc,
                  char** argv,
                  sl_context* ctx,
                  const char* socket_name,
                  const char* peer_cmd_prefix) {
  struct sockaddr_un addr;
  int lock_fd;
  int sock_fd;
  int rv;

  rv = sl_open_wayland_socket(socket_name, &addr, &lock_fd, &sock_fd);
  if (rv < 0)
    return EXIT_FAILURE;

  // Spawn optional child process before we notify systemd that we're ready
  // to accept connections. WAYLAND_DISPLAY will be set but any attempt to
  // connect to this socket at this time will fail.
  if (ctx->runprog && ctx->runprog[0]) {
    int pid = fork();
    errno_assert(pid != -1);
    if (pid == 0) {
      setenv("WAYLAND_DISPLAY", socket_name, 1);
      sl_execvp(ctx->runprog[0], ctx->runprog, -1);
      _exit(EXIT_FAILURE);
    }
    while (waitpid(-1, NULL, WNOHANG) != pid)
      continue;
  }

  if (ctx->sd_notify)
    sl_sd_notify(ctx->sd_notify);

  struct sigaction sa;
  sa.sa_handler = sl_sigchld_handler;
  sigemptyset(&sa.sa_mask);
  sa.sa_flags = SA_RESTART;
  rv = sigaction(SIGCHLD, &sa, NULL);
  errno_assert(rv >= 0);

  do {
    struct ucred ucred;
    socklen_t length = sizeof(addr);

    int client_fd = accept(sock_fd, (struct sockaddr*)&addr, &length);
    if (client_fd < 0) {
      fprintf(stderr, "error: failed to accept: %m\n");
      continue;
    }

    ucred.pid = -1;
    length = sizeof(ucred);
    rv = getsockopt(client_fd, SOL_SOCKET, SO_PEERCRED, &ucred, &length);

    int pid = fork();
    errno_assert(pid != -1);
    if (pid == 0) {
      char* client_fd_str;
      char* peer_pid_str;
      char* peer_cmd_prefix_str;
      char const* args[64];
      int i = 0;

      close(sock_fd);
      close(lock_fd);

      if (peer_cmd_prefix) {
        peer_cmd_prefix_str = sl_xasprintf("%s", peer_cmd_prefix);

        i = sl_parse_cmd_prefix(peer_cmd_prefix_str, 32, args);
        if (i > 32) {
          fprintf(stderr, "error: too many arguments in cmd prefix: %d\n", i);
          i = 0;
        }
      }

      args[i++] = argv[0];
      peer_pid_str = sl_xasprintf("--peer-pid=%d", ucred.pid);
      args[i++] = peer_pid_str;
      client_fd_str = sl_xasprintf("--client-fd=%d", client_fd);
      args[i++] = client_fd_str;

      // forward some flags.
      for (int j = 1; j < argc; ++j) {
        char* arg = argv[j];
        if (strstr(arg, "--display") == arg || strstr(arg, "--scale") == arg ||
            strstr(arg, "--direct-scale") == arg ||
            strstr(arg, "--accelerators") == arg ||
            strstr(arg, "--windowed-accelerators") == arg ||
            strstr(arg, "--drm-device") == arg ||
            strstr(arg, "--support-damage-buffer") == arg ||
            strstr(arg, "--vm-identififer") == arg) {
          args[i++] = arg;
        }
      }

      args[i++] = NULL;

      execvp(args[0], const_cast<char* const*>(args));
      _exit(EXIT_FAILURE);
    }
    close(client_fd);
  } while (1);

  // Control should never reach here.
  assert(false);
}

void sl_spawn_xwayland(sl_context* ctx,
                       wl_event_loop* event_loop,
                       int wayland_socket_fd,
                       const char* xwayland_cmd_prefix,
                       const char* xwayland_path,
                       int xdisplay,
                       const char* xauth_path,
                       const char* xfont_path,
                       const char* xwayland_gl_driver_path,
                       const char* glamor) {
  int ds[2];
  int rv;
  // Xwayland display ready socket.
  rv = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, ds);
  errno_assert(!rv);

  ctx->display_ready_event_source.reset(
      wl_event_loop_add_fd(event_loop, ds[0], WL_EVENT_READABLE,
                           sl_handle_display_ready_event, ctx));

  int wm[2];
  // X connection to Xwayland.
  rv = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, wm);
  errno_assert(!rv);

  ctx->wm_fd = wm[0];

  int pid = fork();
  errno_assert(pid != -1);
  if (pid == 0) {
    char const* args[64];
    int i = 0;

    if (xwayland_cmd_prefix) {
      char* xwayland_cmd_prefix_str = sl_xasprintf("%s", xwayland_cmd_prefix);

      i = sl_parse_cmd_prefix(xwayland_cmd_prefix_str, 32, args);
      if (i > 32) {
        fprintf(stderr, "error: too many arguments in cmd prefix: %d\n", i);
        i = 0;
      }
    }

    args[i++] = sl_xasprintf("%s", xwayland_path ?: XWAYLAND_PATH);

    int fd = dup(ds[1]);
    char* display_fd_str = sl_xasprintf("%d", fd);
    fd = dup(wm[1]);
    char* wm_fd_str = sl_xasprintf("%d", fd);

    if (xdisplay > 0) {
      args[i++] = sl_xasprintf(":%d", xdisplay);
    }
    args[i++] = "-nolisten";
    args[i++] = "tcp";
    args[i++] = "-rootless";
    // Use software rendering unless we have a DRM device and glamor is
    // enabled.
    if (!ctx->drm_device || !glamor || !strcmp(glamor, "0"))
      args[i++] = "-shm";
    args[i++] = "-displayfd";
    args[i++] = display_fd_str;
    args[i++] = "-wm";
    args[i++] = wm_fd_str;
    if (xauth_path) {
      args[i++] = "-auth";
      args[i++] = sl_xasprintf("%s", xauth_path);
    }
    if (xfont_path) {
      args[i++] = "-fp";
      args[i++] = sl_xasprintf("%s", xfont_path);
    }
    args[i++] = NULL;

    // If a path is explicitly specified via command line or environment
    // use that instead of the compiled in default.  In either case, only
    // set the environment variable if the value specified is non-empty.
    if (xwayland_gl_driver_path) {
      if (*xwayland_gl_driver_path) {
        setenv("LIBGL_DRIVERS_PATH", xwayland_gl_driver_path, 1);
      }
    } else if (XWAYLAND_GL_DRIVER_PATH && *XWAYLAND_GL_DRIVER_PATH) {
      setenv("LIBGL_DRIVERS_PATH", XWAYLAND_GL_DRIVER_PATH, 1);
    }

    sl_execvp(args[0], const_cast<char* const*>(args), wayland_socket_fd);
    _exit(EXIT_FAILURE);
  }
  close(wm[1]);
  ctx->xwayland_pid = pid;
}

int real_main(int argc, char** argv) {
  struct sl_context ctx;
  sl_context_init_default(&ctx);

  const char* display = getenv("SOMMELIER_DISPLAY");
  const char* scale = getenv("SOMMELIER_SCALE");
  const char* dpi = getenv("SOMMELIER_DPI");
  const char* clipboard_manager = getenv("SOMMELIER_CLIPBOARD_MANAGER");
  const char* frame_color = getenv("SOMMELIER_FRAME_COLOR");
  const char* dark_frame_color = getenv("SOMMELIER_DARK_FRAME_COLOR");
  const char* support_damage_buffer = getenv("SOMMELIER_SUPPORT_DAMAGE_BUFFER");
  const char* force_drm_device = NULL;
  const char* glamor = getenv("SOMMELIER_GLAMOR");
  const char* fullscreen_mode = getenv("SOMMELIER_FULLSCREEN_MODE");
  const char* peer_cmd_prefix = getenv("SOMMELIER_PEER_CMD_PREFIX");
  const char* xwayland_cmd_prefix = getenv("SOMMELIER_XWAYLAND_CMD_PREFIX");
  const char* accelerators = getenv("SOMMELIER_ACCELERATORS");
  const char* windowed_accelerators = getenv("SOMMELIER_WINDOWED_ACCELERATORS");
  const char* xwayland_path = getenv("SOMMELIER_XWAYLAND_PATH");
  const char* xwayland_gl_driver_path =
      getenv("SOMMELIER_XWAYLAND_GL_DRIVER_PATH");
  const char* xauth_path = getenv("SOMMELIER_XAUTH_PATH");
  const char* xfont_path = getenv("SOMMELIER_XFONT_PATH");
  const char* vm_id = getenv("SOMMELIER_VM_IDENTIFIER");
  const char* socket_name = "wayland-0";
  bool noop_driver = false;
  struct wl_event_loop* event_loop;
  struct wl_listener client_destroy_listener = {};
  client_destroy_listener.notify = sl_client_destroy_notify;
  int sv[2];
  pid_t pid;
  int xdisplay = -1;
  int parent = 0;
  int client_fd = -1;
  int i;

  // Ignore SIGUSR1 (used for trace dumping) in all child processes.
  signal(SIGUSR1, SIG_IGN);

  for (i = 1; i < argc; ++i) {
    const char* arg = argv[i];
    if (strcmp(arg, "--help") == 0 || strcmp(arg, "-h") == 0 ||
        strcmp(arg, "-?") == 0) {
      sl_print_usage();
      return EXIT_SUCCESS;
    }
    if (strcmp(arg, "--version") == 0 || strcmp(arg, "-v") == 0) {
      printf("Version: %s\n", SOMMELIER_VERSION);
      return EXIT_SUCCESS;
    }
    if (strstr(arg, "--parent") == arg) {
      parent = 1;
    } else if (strstr(arg, "--socket") == arg) {
      socket_name = sl_arg_value(arg);
    } else if (strstr(arg, "--display") == arg) {
      display = sl_arg_value(arg);
    } else if (strstr(arg, "--peer-pid") == arg) {
      ctx.peer_pid = atoi(sl_arg_value(arg));
    } else if (strstr(arg, "--peer-cmd-prefix") == arg) {
      peer_cmd_prefix = sl_arg_value(arg);
    } else if (strstr(arg, "--xwayland-cmd-prefix") == arg) {
      xwayland_cmd_prefix = sl_arg_value(arg);
    } else if (strstr(arg, "--client-fd") == arg) {
      client_fd = atoi(sl_arg_value(arg));
    } else if (strstr(arg, "--direct-scale") == arg) {
      ctx.use_direct_scale = true;
    } else if (strstr(arg, "--scale") == arg) {
      scale = sl_arg_value(arg);
    } else if (strstr(arg, "--dpi") == arg) {
      dpi = sl_arg_value(arg);
    } else if (strstr(arg, "--accelerators") == arg) {
      accelerators = sl_arg_value(arg);
    } else if (strstr(arg, "--windowed-accelerators") == arg) {
      windowed_accelerators = sl_arg_value(arg);
    } else if (strstr(arg, "--vm-identifier") == arg) {
      vm_id = sl_arg_value(arg);
    } else if (strstr(arg, "--application-id-x11-property") == arg) {
      // NB: Must be parsed before --application-id.
      ctx.application_id_property_name = sl_arg_value(arg);
    } else if (strstr(arg, "--application-id") == arg) {
      ctx.application_id = sl_arg_value(arg);
    } else if (strstr(arg, "-X") == arg) {
      ctx.xwayland = 1;
    } else if (strstr(arg, "--x-display") == arg) {
      xdisplay = atoi(sl_arg_value(arg));
      // Automatically enable X forwarding if X display is specified.
      ctx.xwayland = 1;
    } else if (strstr(arg, "--xwayland-path") == arg) {
      xwayland_path = sl_arg_value(arg);
    } else if (strstr(arg, "--xwayland-gl-driver-path") == arg) {
      xwayland_gl_driver_path = sl_arg_value(arg);
    } else if (strstr(arg, "--no-exit-with-child") == arg) {
      ctx.exit_with_child = 0;
    } else if (strstr(arg, "--sd-notify") == arg) {
      ctx.sd_notify = sl_arg_value(arg);
    } else if (strstr(arg, "--no-clipboard-manager") == arg) {
      clipboard_manager = "0";
    } else if (strstr(arg, "--frame-color") == arg) {
      frame_color = sl_arg_value(arg);
    } else if (strstr(arg, "--dark-frame-color") == arg) {
      dark_frame_color = sl_arg_value(arg);
    } else if (strstr(arg, "--force-drm-device") == arg) {
      force_drm_device = sl_arg_value(arg);
    } else if (strstr(arg, "--no-support-damage-buffer") == arg) {
      support_damage_buffer = "0";
    } else if (strstr(arg, "--glamor") == arg) {
      glamor = "1";
    } else if (strstr(arg, "--fullscreen-mode") == arg) {
      fullscreen_mode = sl_arg_value(arg);
    } else if (strstr(arg, "--x-auth") == arg) {
      xauth_path = sl_arg_value(arg);
    } else if (strstr(arg, "--x-font-path") == arg) {
      xfont_path = sl_arg_value(arg);
    } else if (strstr(arg, "--timing-filename") == arg) {
      ctx.timing = new Timing(sl_arg_value(arg));
    } else if (strstr(arg, "--explicit-fence") == arg) {
      ctx.use_explicit_fence = true;
    } else if (strstr(arg, "--enable-xshape") == arg) {
      ctx.enable_xshape = true;
    } else if (strstr(arg, "--virtgpu-channel") == arg) {
      ctx.use_virtgpu_channel = true;
    } else if (strstr(arg, "--noop-driver") == arg) {
      noop_driver = true;
#ifdef PERFETTO_TRACING
    } else if (strstr(arg, "--trace-filename") == arg) {
      ctx.trace_filename = sl_arg_value(arg);
    } else if (strstr(arg, "--trace-system") == arg) {
      ctx.trace_system = true;
#endif
    } else if (arg[0] == '-') {
      if (strcmp(arg, "--") == 0) {
        ctx.runprog = &argv[i + 1];
        break;
      }
      // Don't exit on unknown options so we can have forward compatibility
      // with new flags introduced.
      fprintf(stderr, "Option `%s' is unknown, ignoring.\n", arg);
    } else {
      ctx.runprog = &argv[i];
      break;
    }
  }

  if (vm_id && strlen(vm_id)) {
    // Some GuestOS instances of sommelier will be started with vm_id set to a
    // container_token from /dev/.container_token.
    // The vm_id may be empty if the token or file does not yet exist.
    // Keep the vm_id as default (termina) if this occurs.
    ctx.vm_id = vm_id;
  }

  if (ctx.application_id && ctx.vm_id) {
    fprintf(stderr, "warning: --application-id overrides --vm-identifier\n");
  }
  if (ctx.application_id && ctx.application_id_property_name) {
    fprintf(stderr,
            "warning: --application-id overrides"
            " --application-id-x11-property\n");
  }

  if (parent) {
    return sl_run_parent(argc, argv, &ctx, socket_name, peer_cmd_prefix);
  }

  if (client_fd == -1) {
    if (!ctx.runprog || !ctx.runprog[0]) {
      sl_print_usage();
      return EXIT_FAILURE;
    }
  }

  if (ctx.xwayland) {
    assert(client_fd == -1);

    ctx.clipboard_manager = 1;
    if (clipboard_manager)
      ctx.clipboard_manager = !!strcmp(clipboard_manager, "0");
  }

  if (scale) {
    ctx.desired_scale = atof(scale);
    // Round to integer scale until we detect wp_viewporter support.
    // In direct scale mode, take the scale value as is.

    if (ctx.use_direct_scale) {
      ctx.scale = ctx.desired_scale;
    } else {
      ctx.scale = MIN(MAX_SCALE, MAX(MIN_SCALE, round(ctx.desired_scale)));
    }
  }

  if (!frame_color)
    frame_color = FRAME_COLOR;

  if (frame_color) {
    int r, g, b;
    if (sscanf(frame_color, "#%02x%02x%02x", &r, &g, &b) == 3)
      ctx.frame_color = 0xff000000 | (r << 16) | (g << 8) | (b << 0);
  }

  if (!dark_frame_color)
    dark_frame_color = DARK_FRAME_COLOR;

  if (dark_frame_color) {
    int r, g, b;
    if (sscanf(dark_frame_color, "#%02x%02x%02x", &r, &g, &b) == 3)
      ctx.dark_frame_color = 0xff000000 | (r << 16) | (g << 8) | (b << 0);
  }

  ctx.support_damage_buffer = support_damage_buffer == nullptr ||
                              strcmp(support_damage_buffer, "1") == 0;

  if (fullscreen_mode) {
    if (strcmp(fullscreen_mode, "immersive") == 0) {
      ctx.fullscreen_mode = ZAURA_SURFACE_FULLSCREEN_MODE_IMMERSIVE;
    } else if (strcmp(fullscreen_mode, "plain") == 0) {
      ctx.fullscreen_mode = ZAURA_SURFACE_FULLSCREEN_MODE_PLAIN;
    } else {
      fprintf(stderr, "error: unrecognised --fullscreen-mode\n");
      sl_print_usage();
      return EXIT_FAILURE;
    }
  }

  // Handle broken pipes without signals that kill the entire process.
  signal(SIGPIPE, SIG_IGN);

  ctx.host_display = wl_display_create();
  assert(ctx.host_display);

  if (noop_driver) {
    ctx.channel = NULL;
  } else if (ctx.use_virtgpu_channel) {
    ctx.channel = new VirtGpuChannel();
  } else {
    ctx.channel = new VirtWaylandChannel();
  }

  event_loop = wl_display_get_event_loop(ctx.host_display);
  if (!sl_context_init_wayland_channel(&ctx, event_loop, display)) {
    return EXIT_FAILURE;
  }

  int drm_fd = -1;
  char* drm_device = NULL;
  if (force_drm_device != NULL) {
    // Use DRM device specified on the command line.
    drm_fd = open(force_drm_device, O_RDWR | O_CLOEXEC);
    if (drm_fd == -1) {
      fprintf(stderr, "error: could not open %s (%s)\n", force_drm_device,
              strerror(errno));
      return EXIT_FAILURE;
    }
    drm_device = strdup(force_drm_device);
  } else {
    // Enumerate render nodes to find the virtio_gpu device.
    drm_fd = open_virtgpu(&drm_device);
  }
  if (drm_fd >= 0) {
    ctx.gbm = gbm_create_device(drm_fd);
    if (!ctx.gbm) {
      fprintf(stderr, "error: couldn't get display device\n");
      return EXIT_FAILURE;
    }

    ctx.drm_device = drm_device;
  }

  wl_array_init(&ctx.dpi);
  if (dpi) {
    char* str = strdup(dpi);
    char* token = strtok(str, ",");  // NOLINT(runtime/threadsafe_fn)
    int* p;

    while (token) {
      p = static_cast<int*>(wl_array_add(&ctx.dpi, sizeof *p));
      assert(p);
      *p = MAX(MIN_DPI, MIN(atoi(token), MAX_DPI));
      token = strtok(NULL, ",");  // NOLINT(runtime/threadsafe_fn)
    }
    free(str);
  }

  // The success of this depends on xkb-data being installed.
  ctx.xkb_context = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
  if (!ctx.xkb_context) {
    fprintf(stderr, "error: xkb_context_new failed. xkb-data missing?\n");
    return EXIT_FAILURE;
  }

  if (ctx.virtwl_display_fd != -1) {
    ctx.display = wl_display_connect_to_fd(ctx.virtwl_display_fd);
  } else {
    if (display == NULL)
      display = getenv("WAYLAND_DISPLAY");
    if (display == NULL)
      display = "wayland-0";

    ctx.display = wl_display_connect(display);
  }

  if (!ctx.display) {
    fprintf(stderr, "error: failed to connect to %s\n", display);
    return EXIT_FAILURE;
  }

  if (!sl_parse_accelerators(&ctx.accelerators, accelerators))
    return EXIT_FAILURE;
  if (!sl_parse_accelerators(&ctx.windowed_accelerators, windowed_accelerators))
    return EXIT_FAILURE;

  ctx.display_event_source.reset(
      wl_event_loop_add_fd(event_loop, wl_display_get_fd(ctx.display),
                           WL_EVENT_READABLE, sl_handle_event, &ctx));

  wl_registry_add_listener(wl_display_get_registry(ctx.display),
                           &sl_registry_listener, &ctx);

  if (ctx.runprog || ctx.xwayland) {
    // Wayland connection from client.
    int rv = socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, sv);
    errno_assert(!rv);
    client_fd = sv[0];
  }

  ctx.client = wl_client_create(ctx.host_display, client_fd);

  // Replace the core display implementation. This is needed in order to
  // implement sync handler properly.
  sl_set_display_implementation(&ctx, ctx.client);

  if (ctx.runprog || ctx.xwayland) {
    ctx.sigchld_event_source.reset(
        wl_event_loop_add_signal(event_loop, SIGCHLD, sl_handle_sigchld, &ctx));

    if (ctx.xwayland) {
      sl_spawn_xwayland(&ctx, event_loop, sv[1], xwayland_cmd_prefix,
                        xwayland_path, xdisplay, xauth_path, xfont_path,
                        xwayland_gl_driver_path, glamor);
    } else {
      pid = fork();
      errno_assert(pid != -1);
      if (pid == 0) {
        // Unset DISPLAY to prevent X clients from connecting to an existing X
        // server when X forwarding is not enabled.
        unsetenv("DISPLAY");
        sl_execvp(ctx.runprog[0], ctx.runprog, sv[1]);
        _exit(EXIT_FAILURE);
      }
      ctx.child_pid = pid;
    }
    close(sv[1]);
  }

  // Attempt to enable tracing.  This could be called earlier but would rather
  // spawn all children first.
  const bool tracing_needed = ctx.trace_filename || ctx.trace_system;
  if (tracing_needed) {
    initialize_tracing(ctx.trace_filename, ctx.trace_system);
    enable_tracing(!ctx.trace_system);
  }

  // Trigger trace and timing log dumps when USR1 signals are received
  if (tracing_needed || ctx.timing) {
    ctx.sigusr1_event_source.reset(
        wl_event_loop_add_signal(event_loop, SIGUSR1, sl_handle_sigusr1, &ctx));
  }

  // Initialize timing log values.
  if (ctx.timing) {
    ctx.timing->RecordStartTime();
  }

  wl_client_add_destroy_listener(ctx.client, &client_destroy_listener);

  do {
    wl_display_flush_clients(ctx.host_display);
    if (ctx.connection) {
      if (ctx.needs_set_input_focus) {
        sl_set_input_focus(&ctx, ctx.host_focus_window);
        ctx.needs_set_input_focus = 0;
      }
      xcb_flush(ctx.connection);
    }
    if (wl_display_flush(ctx.display) < 0)
      return EXIT_FAILURE;

    if (wl_event_loop_dispatch(event_loop, -1) == -1) {
      // Ignore EINTR or sommelier will exit when attached by strace or gdb.
      if (errno != EINTR)
        return EXIT_FAILURE;
    }
  } while (1);

  return EXIT_SUCCESS;
}  // NOLINT(readability/fn_size)