mutter/src/core/async-getprop.c

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/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* Asynchronous X property getting hack */
/*
* Copyright (C) 2002 Havoc Pennington
* Copyright (C) 1986, 1998 The Open Group
*
* Permission to use, copy, modify, distribute, and sell this software
* and its documentation for any purpose is hereby granted without
* fee, provided that the above copyright notice appear in all copies
* and that both that copyright notice and this permission notice
* appear in supporting documentation.
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE OPEN GROUP BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* Except as contained in this notice, the name of The Open Group shall not be
* used in advertising or otherwise to promote the sale, use or other dealings
* in this Software without prior written authorization from The Open Group.
*/
#include <assert.h>
#undef DEBUG_SPEW
#ifdef DEBUG_SPEW
#include <stdio.h>
#endif
#include "async-getprop.h"
#define NEED_REPLIES
#include <X11/Xlibint.h>
#ifndef NULL
#define NULL ((void*)0)
#endif
typedef struct _ListNode ListNode;
typedef struct _AgPerDisplayData AgPerDisplayData;
struct _ListNode
{
ListNode *next;
};
struct _AgGetPropertyTask
{
ListNode node;
AgPerDisplayData *dd;
Window window;
Atom property;
unsigned long request_seq;
int error;
Atom actual_type;
int actual_format;
unsigned long n_items;
unsigned long bytes_after;
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char *data;
Bool have_reply;
};
struct _AgPerDisplayData
{
ListNode node;
_XAsyncHandler async;
Display *display;
ListNode *pending_tasks;
ListNode *pending_tasks_tail;
ListNode *completed_tasks;
ListNode *completed_tasks_tail;
int n_tasks_pending;
int n_tasks_completed;
};
static ListNode *display_datas = NULL;
static ListNode *display_datas_tail = NULL;
static void
append_to_list (ListNode **head,
ListNode **tail,
ListNode *task)
{
task->next = NULL;
if (*tail == NULL)
{
assert (*head == NULL);
*head = task;
*tail = task;
}
else
{
(*tail)->next = task;
*tail = task;
}
}
static void
remove_from_list (ListNode **head,
ListNode **tail,
ListNode *task)
{
ListNode *prev;
ListNode *node;
prev = NULL;
node = *head;
while (node != NULL)
{
if (node == task)
{
if (prev)
prev->next = node->next;
else
*head = node->next;
if (node == *tail)
*tail = prev;
break;
}
prev = node;
node = node->next;
}
/* can't remove what's not there */
assert (node != NULL);
node->next = NULL;
}
static void
move_to_completed (AgPerDisplayData *dd,
AgGetPropertyTask *task)
{
remove_from_list (&dd->pending_tasks,
&dd->pending_tasks_tail,
&task->node);
append_to_list (&dd->completed_tasks,
&dd->completed_tasks_tail,
&task->node);
dd->n_tasks_pending -= 1;
dd->n_tasks_completed += 1;
}
static AgGetPropertyTask*
find_pending_by_request_sequence (AgPerDisplayData *dd,
unsigned long request_seq)
{
ListNode *node;
/* if the sequence is after our last pending task, we
* aren't going to find a match
*/
{
AgGetPropertyTask *task = (AgGetPropertyTask*) dd->pending_tasks_tail;
if (task != NULL)
{
if (task->request_seq < request_seq)
return NULL;
else if (task->request_seq == request_seq)
return task; /* why not check this */
}
}
/* Generally we should get replies in the order we sent
* requests, so we should usually be using the task
* at the head of the list, if we use any task at all.
* I'm not sure this is 100% guaranteed, if it is,
* it would be a big speedup.
*/
node = dd->pending_tasks;
while (node != NULL)
{
AgGetPropertyTask *task = (AgGetPropertyTask*) node;
if (task->request_seq == request_seq)
return task;
node = node->next;
}
return NULL;
}
static Bool
async_get_property_handler (Display *dpy,
xReply *rep,
char *buf,
int len,
XPointer data)
{
xGetPropertyReply replbuf;
xGetPropertyReply *reply;
AgGetPropertyTask *task;
AgPerDisplayData *dd;
int bytes_read;
dd = (AgPerDisplayData*) data;
#if 0
printf ("%s: seeing request seq %ld buflen %d\n", __FUNCTION__,
dpy->last_request_read, len);
#endif
task = find_pending_by_request_sequence (dd, dpy->last_request_read);
if (task == NULL)
return False;
assert (dpy->last_request_read == task->request_seq);
task->have_reply = True;
move_to_completed (dd, task);
/* read bytes so far */
bytes_read = SIZEOF (xReply);
if (rep->generic.type == X_Error)
{
xError errbuf;
task->error = rep->error.errorCode;
#ifdef DEBUG_SPEW
printf ("%s: error code = %d (ignoring error, eating %d bytes, generic.length = %ld)\n",
__FUNCTION__, task->error, (SIZEOF (xError) - bytes_read),
rep->generic.length);
#endif
/* We return True (meaning we consumed the reply)
* because otherwise it would invoke the X error handler,
* and an async API is useless if you have to synchronously
* trap X errors. Also GetProperty can always fail, pretty
* much, so trapping errors is always what you want.
*
* We have to eat all the error reply data here.
* (kind of a charade as we know sizeof(xError) == sizeof(xReply))
*
* Passing discard = True seems to break things; I don't understand
* why, because there should be no extra data in an error reply,
* right?
*/
_XGetAsyncReply (dpy, (char *)&errbuf, rep, buf, len,
(SIZEOF (xError) - bytes_read) >> 2, /* in 32-bit words */
False); /* really seems like it should be True */
return True;
}
#ifdef DEBUG_SPEW
printf ("%s: already read %d bytes reading %d more for total of %d; generic.length = %ld\n",
__FUNCTION__, bytes_read, (SIZEOF (xGetPropertyReply) - bytes_read) >> 2,
SIZEOF (xGetPropertyReply), rep->generic.length);
#endif
/* (kind of a silly as we know sizeof(xGetPropertyReply) == sizeof(xReply)) */
reply = (xGetPropertyReply *)
_XGetAsyncReply (dpy, (char *)&replbuf, rep, buf, len,
(SIZEOF (xGetPropertyReply) - bytes_read) >> 2, /* in 32-bit words */
False); /* False means expecting more data to follow,
* don't eat the rest of the reply
*/
bytes_read = SIZEOF (xGetPropertyReply);
#ifdef DEBUG_SPEW
printf ("%s: have reply propertyType = %ld format = %d n_items = %ld\n",
__FUNCTION__, reply->propertyType, reply->format, reply->nItems);
#endif
assert (task->data == NULL);
/* This is all copied from XGetWindowProperty(). Not sure we should
* LockDisplay(). Not sure I'm passing the right args to
* XGetAsyncData(). Not sure about a lot of things.
*/
/* LockDisplay (dpy); */
if (reply->propertyType != None)
{
long nbytes, netbytes;
/* this alignment macro from orbit2 */
#define ALIGN_VALUE(this, boundary) \
(( ((unsigned long)(this)) + (((unsigned long)(boundary)) -1)) & (~(((unsigned long)(boundary))-1)))
switch (reply->format)
{
/*
* One extra byte is malloced than is needed to contain the property
* data, but this last byte is null terminated and convenient for
* returning string properties, so the client doesn't then have to
* recopy the string to make it null terminated.
*/
case 8:
nbytes = reply->nItems;
/* there's padding to word boundary */
netbytes = ALIGN_VALUE (nbytes, 4);
if (nbytes + 1 > 0 &&
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(task->data = (char *) Xmalloc ((unsigned)nbytes + 1)))
{
#ifdef DEBUG_SPEW
printf ("%s: already read %d bytes using %ld, more eating %ld more\n",
__FUNCTION__, bytes_read, nbytes, netbytes);
#endif
/* _XReadPad (dpy, (char *) task->data, netbytes); */
_XGetAsyncData (dpy, task->data, buf, len,
bytes_read, nbytes,
netbytes);
}
break;
case 16:
nbytes = reply->nItems * sizeof (short);
netbytes = reply->nItems << 1;
netbytes = ALIGN_VALUE (netbytes, 4); /* align to word boundary */
if (nbytes + 1 > 0 &&
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(task->data = (char *) Xmalloc ((unsigned)nbytes + 1)))
{
#ifdef DEBUG_SPEW
printf ("%s: already read %d bytes using %ld more, eating %ld more\n",
__FUNCTION__, bytes_read, nbytes, netbytes);
#endif
/* _XRead16Pad (dpy, (short *) task->data, netbytes); */
_XGetAsyncData (dpy, task->data, buf, len,
bytes_read, nbytes, netbytes);
}
break;
case 32:
/* NOTE buffer is in longs to match XGetWindowProperty() */
nbytes = reply->nItems * sizeof (long);
netbytes = reply->nItems << 2; /* wire size is always 32 bits though */
if (nbytes + 1 > 0 &&
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(task->data = (char *) Xmalloc ((unsigned)nbytes + 1)))
{
#ifdef DEBUG_SPEW
printf ("%s: already read %d bytes using %ld more, eating %ld more\n",
__FUNCTION__, bytes_read, nbytes, netbytes);
#endif
/* We have to copy the XGetWindowProperty() crackrock
* and get format 32 as long even on 64-bit platforms.
*/
if (sizeof (long) == 8)
{
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char *netdata;
char *lptr;
char *end_lptr;
/* Store the 32-bit values in the end of the array */
netdata = task->data + nbytes / 2;
_XGetAsyncData (dpy, netdata, buf, len,
bytes_read, netbytes,
netbytes);
/* Now move the 32-bit values to the front */
lptr = task->data;
end_lptr = task->data + nbytes;
while (lptr != end_lptr)
{
*(long*) lptr = *(CARD32*) netdata;
lptr += sizeof (long);
netdata += sizeof (CARD32);
}
}
else
{
/* Here the wire format matches our actual format */
_XGetAsyncData (dpy, task->data, buf, len,
bytes_read, netbytes,
netbytes);
}
}
break;
default:
/*
* This part of the code should never be reached. If it is,
* the server sent back a property with an invalid format.
* This is a BadImplementation error.
*
* However this async GetProperty API doesn't report errors
* via the standard X mechanism, so don't do anything about
* it, other than store it in task->error.
*/
task->error = BadImplementation;
nbytes = netbytes = 0L;
break;
}
if (task->data == NULL)
{
task->error = BadAlloc;
#ifdef DEBUG_SPEW
printf ("%s: already read %d bytes eating %ld\n",
__FUNCTION__, bytes_read, netbytes);
#endif
/* _XEatData (dpy, (unsigned long) netbytes); */
_XGetAsyncData (dpy, NULL, buf, len,
bytes_read, 0, netbytes);
/* UnlockDisplay (dpy); */
return BadAlloc; /* not Success */
}
(task->data)[nbytes] = '\0';
}
#ifdef DEBUG_SPEW
printf ("%s: have data\n", __FUNCTION__);
#endif
task->actual_type = reply->propertyType;
task->actual_format = reply->format;
task->n_items = reply->nItems;
task->bytes_after = reply->bytesAfter;
/* UnlockDisplay (dpy); */
return True;
}
static AgPerDisplayData*
get_display_data (Display *display,
Bool create)
{
ListNode *node;
AgPerDisplayData *dd;
node = display_datas;
while (node != NULL)
{
dd = (AgPerDisplayData*) node;
if (dd->display == display)
return dd;
node = node->next;
}
if (!create)
return NULL;
dd = Xcalloc (1, sizeof (AgPerDisplayData));
if (dd == NULL)
return NULL;
dd->display = display;
dd->async.next = display->async_handlers;
dd->async.handler = async_get_property_handler;
dd->async.data = (XPointer) dd;
dd->display->async_handlers = &dd->async;
append_to_list (&display_datas,
&display_datas_tail,
&dd->node);
return dd;
}
static void
maybe_free_display_data (AgPerDisplayData *dd)
{
if (dd->pending_tasks == NULL &&
dd->completed_tasks == NULL)
{
DeqAsyncHandler (dd->display, &dd->async);
remove_from_list (&display_datas, &display_datas_tail,
&dd->node);
XFree (dd);
}
}
AgGetPropertyTask*
ag_task_create (Display *dpy,
Window window,
Atom property,
long offset,
long length,
Bool delete,
Atom req_type)
{
AgGetPropertyTask *task;
xGetPropertyReq *req;
AgPerDisplayData *dd;
/* Fire up our request */
LockDisplay (dpy);
dd = get_display_data (dpy, True);
if (dd == NULL)
{
UnlockDisplay (dpy);
return NULL;
}
GetReq (GetProperty, req);
req->window = window;
req->property = property;
req->type = req_type;
req->delete = delete;
req->longOffset = offset;
req->longLength = length;
/* Queue up our async task */
task = Xcalloc (1, sizeof (AgGetPropertyTask));
if (task == NULL)
{
UnlockDisplay (dpy);
return NULL;
}
task->dd = dd;
task->window = window;
task->property = property;
task->request_seq = dpy->request;
append_to_list (&dd->pending_tasks,
&dd->pending_tasks_tail,
&task->node);
dd->n_tasks_pending += 1;
UnlockDisplay (dpy);
SyncHandle ();
return task;
}
static void
free_task (AgGetPropertyTask *task)
{
remove_from_list (&task->dd->completed_tasks,
&task->dd->completed_tasks_tail,
&task->node);
task->dd->n_tasks_completed -= 1;
maybe_free_display_data (task->dd);
XFree (task);
}
Status
ag_task_get_reply_and_free (AgGetPropertyTask *task,
Atom *actual_type,
int *actual_format,
unsigned long *nitems,
unsigned long *bytesafter,
unsigned char **prop)
{
Display *dpy;
*prop = NULL;
dpy = task->dd->display; /* Xlib macros require a variable named "dpy" */
if (task->error != Success)
{
Status s = task->error;
free_task (task);
return s;
}
if (!task->have_reply)
{
free_task (task);
return BadAlloc; /* not Success */
}
*actual_type = task->actual_type;
*actual_format = task->actual_format;
*nitems = task->n_items;
*bytesafter = task->bytes_after;
*prop = (unsigned char*) task->data; /* pass out ownership of task->data */
SyncHandle ();
free_task (task);
return Success;
}
Bool
ag_task_have_reply (AgGetPropertyTask *task)
{
return task->have_reply;
}
Atom
ag_task_get_property (AgGetPropertyTask *task)
{
return task->property;
}
Window
ag_task_get_window (AgGetPropertyTask *task)
{
return task->window;
}
Display*
ag_task_get_display (AgGetPropertyTask *task)
{
return task->dd->display;
}
AgGetPropertyTask*
ag_get_next_completed_task (Display *display)
{
AgPerDisplayData *dd;
dd = get_display_data (display, False);
if (dd == NULL)
return NULL;
#ifdef DEBUG_SPEW
printf ("%d pending %d completed\n",
dd->n_tasks_pending,
dd->n_tasks_completed);
#endif
return (AgGetPropertyTask*) dd->completed_tasks;
}
void*
ag_Xmalloc (unsigned long bytes)
{
return (void*) Xmalloc (bytes);
}
void*
ag_Xmalloc0 (unsigned long bytes)
{
return (void*) Xcalloc (bytes, 1);
}