extensions-tool: Implement list command

Seeing at a glance which extensions are installed is surely useful,
so add a corresponding command.

https://gitlab.gnome.org/GNOME/gnome-shell/issues/1234

src/extensions-tool/command-list.c

@@ -0,0 +1,92 @@
+/* command-list.c
+ *
+ * Copyright 2018 Florian Müllner <fmuellner@gnome.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include <glib/gi18n.h>
+#include <gio/gio.h>
+
+#include "commands.h"
+#include "common.h"
+
+static gboolean
+list_extensions (void)
+{
+  g_autoptr (GDBusProxy) proxy = NULL;
+  g_autoptr (GVariant) response = NULL;
+  g_autoptr (GVariant) extensions = NULL;
+  g_autoptr (GError) error = NULL;
+  GVariantIter iter;
+  GVariant *value;
+  char *uuid;
+
+  proxy = get_shell_proxy (&error);
+  if (proxy == NULL)
+    return FALSE;
+
+  response = g_dbus_proxy_call_sync (proxy,
+                                     "ListExtensions",
+                                     NULL,
+                                     0,
+                                     -1,
+                                     NULL,
+                                     &error);
+  if (response == NULL)
+    return FALSE;
+
+  extensions = g_variant_get_child_value (response, 0);
+
+  g_variant_iter_init (&iter, extensions);
+  while (g_variant_iter_loop (&iter, "{s@a{sv}}", &uuid, &value))
+    g_print ("%s\n", uuid);
+
+  return TRUE;
+}
+
+int
+handle_list (int argc, char *argv[], gboolean do_help)
+{
+  g_autoptr (GOptionContext) context = NULL;
+  g_autoptr (GError) error = NULL;
+
+  g_set_prgname ("gnome-extensions list");
+
+  context = g_option_context_new (NULL);
+  g_option_context_set_help_enabled (context, FALSE);
+  g_option_context_set_summary (context, _("List installed extensions"));
+
+  if (do_help)
+    {
+      show_help (context, NULL);
+      return 0;
+    }
+
+  if (!g_option_context_parse (context, &argc, &argv, &error))
+    {
+      show_help (context, error->message);
+      return 1;
+    }
+
+  if (argc > 1)
+    {
+      show_help (context, _("Unknown arguments"));
+      return 1;
+    }
+
+  return list_extensions () ? 0 : 2;
+}

src/extensions-tool/commands.h

@@ -26,6 +26,7 @@ G_BEGIN_DECLS
 
 int handle_enable     (int argc, char *argv[], gboolean do_help);
 int handle_disable    (int argc, char *argv[], gboolean do_help);
+int handle_list       (int argc, char *argv[], gboolean do_help);
 int handle_create     (int argc, char *argv[], gboolean do_help);
 
 G_END_DECLS

src/extensions-tool/main.c

@@ -100,6 +100,7 @@ usage (void)
   g_printerr ("  version   %s\n", _("Print version"));
   g_printerr ("  enable    %s\n", _("Enable extension"));
   g_printerr ("  disable   %s\n", _("Disable extension"));
+  g_printerr ("  list      %s\n", _("List extensions"));
   g_printerr ("  create    %s\n", _("Create extension"));
   g_printerr ("\n");
   g_printerr (_("Use %s to get detailed help.\n"), "“gnome-extensions help COMMAND”");
@@ -158,6 +159,8 @@ main (int argc, char *argv[])
     return handle_enable (argc, argv, do_help);
   else if (g_str_equal (command, "disable"))
     return handle_disable (argc, argv, do_help);
+  else if (g_str_equal (command, "list"))
+    return handle_list (argc, argv, do_help);
   else if (g_str_equal (command, "create"))
     return handle_create (argc, argv, do_help);
   else

src/extensions-tool/meson-src.build

@@ -3,6 +3,7 @@ sources = [
   'command-create.c',
   'command-disable.c',
   'command-enable.c',
+  'command-list.c',
   'common.h',
   'main.c'
 ]

src/extensions-tool/meson.build

@@ -12,6 +12,7 @@ sources = [
   'command-create.c',
   'command-disable.c',
   'command-enable.c',
+  'command-list.c',
   'main.c'
 ]