cairo/src/cairo-xlib-display.c

/* Cairo - a vector graphics library with display and print output
 *
 * Copyright © 2007 Chris Wilson
 *
 * This library is free software; you can redistribute it and/or
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 * You should have received a copy of the MPL along with this library
 * in the file COPYING-MPL-1.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 *
 * The Original Code is the cairo graphics library.
 *
 * The Initial Developer of the Original Code is Chris Wilson.
 *
 * Contributor(s):
 *	Karl Tomlinson <karlt+@karlt.net>, Mozilla Corporation
 */

#include "cairoint.h"

#include "cairo-xlib-private.h"
#include "cairo-xlib-xrender-private.h"

#include "cairo-error-private.h"
#include "cairo-freelist-private.h"

#include <X11/Xlibint.h>	/* For XESetCloseDisplay */

struct _cairo_xlib_display {
    cairo_xlib_display_t *next;
    cairo_reference_count_t ref_count;
    cairo_mutex_t mutex;

    Display *display;
    cairo_xlib_screen_t *screens;

    int render_major;
    int render_minor;
    XRenderPictFormat *cached_xrender_formats[CAIRO_FORMAT_A1 + 1];

    cairo_xlib_job_t *workqueue;
    cairo_freelist_t wq_freelist;

    cairo_xlib_hook_t *close_display_hooks;
    unsigned int buggy_gradients :1;
    unsigned int buggy_pad_reflect :1;
    unsigned int buggy_repeat :1;
    unsigned int closed :1;
};

typedef int (*cairo_xlib_error_func_t) (Display     *display,
					XErrorEvent *event);

struct _cairo_xlib_job {
    cairo_xlib_job_t *next;
    enum {
	RESOURCE,
	WORK
    } type;
    union {
	struct {
	    cairo_xlib_notify_resource_func notify;
	    XID xid;
	} resource;
	struct {
	    cairo_xlib_notify_func notify;
	    void *data;
	    void (*destroy) (void *);
	} work;
    } func;
};

static cairo_xlib_display_t *_cairo_xlib_display_list;

static void
_cairo_xlib_remove_close_display_hook_internal (cairo_xlib_display_t *display,
						cairo_xlib_hook_t *hook);

static void
_cairo_xlib_call_close_display_hooks (cairo_xlib_display_t *display)
{
    cairo_xlib_screen_t	    *screen;
    cairo_xlib_hook_t		    *hook;

    /* call all registered shutdown routines */
    CAIRO_MUTEX_LOCK (display->mutex);

    for (screen = display->screens; screen != NULL; screen = screen->next)
	_cairo_xlib_screen_close_display (screen);

    while (TRUE) {
	hook = display->close_display_hooks;
	if (hook == NULL)
	    break;

	_cairo_xlib_remove_close_display_hook_internal (display, hook);

	CAIRO_MUTEX_UNLOCK (display->mutex);
	hook->func (display, hook);
	CAIRO_MUTEX_LOCK (display->mutex);
    }
    display->closed = TRUE;

    CAIRO_MUTEX_UNLOCK (display->mutex);
}

static void
_cairo_xlib_display_discard_screens (cairo_xlib_display_t *display)
{
    cairo_xlib_screen_t *screens;

    CAIRO_MUTEX_LOCK (display->mutex);
    screens = display->screens;
    display->screens = NULL;
    CAIRO_MUTEX_UNLOCK (display->mutex);

    while (screens != NULL) {
	cairo_xlib_screen_t *screen = screens;
	screens = screen->next;

	_cairo_xlib_screen_destroy (screen);
    }
}

cairo_xlib_display_t *
_cairo_xlib_display_reference (cairo_xlib_display_t *display)
{
    assert (CAIRO_REFERENCE_COUNT_HAS_REFERENCE (&display->ref_count));

    _cairo_reference_count_inc (&display->ref_count);

    return display;
}

void
_cairo_xlib_display_destroy (cairo_xlib_display_t *display)
{
    assert (CAIRO_REFERENCE_COUNT_HAS_REFERENCE (&display->ref_count));

    if (! _cairo_reference_count_dec_and_test (&display->ref_count))
	return;

    /* destroy all outstanding notifies */
    while (display->workqueue != NULL) {
	cairo_xlib_job_t *job = display->workqueue;
	display->workqueue = job->next;

	if (job->type == WORK && job->func.work.destroy != NULL)
	    job->func.work.destroy (job->func.work.data);

	_cairo_freelist_free (&display->wq_freelist, job);
    }
    _cairo_freelist_fini (&display->wq_freelist);

    CAIRO_MUTEX_FINI (display->mutex);

    free (display);
}

static int
_noop_error_handler (Display     *display,
		     XErrorEvent *event)
{
    return False;		/* return value is ignored */
}
static int
_cairo_xlib_close_display (Display *dpy, XExtCodes *codes)
{
    cairo_xlib_display_t *display, **prev, *next;
    cairo_xlib_error_func_t old_handler;

    CAIRO_MUTEX_LOCK (_cairo_xlib_display_mutex);
    for (display = _cairo_xlib_display_list; display; display = display->next)
	if (display->display == dpy)
	    break;
    CAIRO_MUTEX_UNLOCK (_cairo_xlib_display_mutex);
    if (display == NULL)
	return 0;

    /* protect the notifies from triggering XErrors */
    XSync (dpy, False);
    old_handler = XSetErrorHandler (_noop_error_handler);

    _cairo_xlib_display_notify (display);
    _cairo_xlib_call_close_display_hooks (display);
    _cairo_xlib_display_discard_screens (display);

    /* catch any that arrived before marking the display as closed */
    _cairo_xlib_display_notify (display);

    XSync (dpy, False);
    XSetErrorHandler (old_handler);

    /*
     * Unhook from the global list
     */
    CAIRO_MUTEX_LOCK (_cairo_xlib_display_mutex);
    prev = &_cairo_xlib_display_list;
    for (display = _cairo_xlib_display_list; display; display = next) {
	next = display->next;
	if (display->display == dpy) {
	    *prev = next;
	    break;
	} else
	    prev = &display->next;
    }
    CAIRO_MUTEX_UNLOCK (_cairo_xlib_display_mutex);

    assert (display != NULL);
    _cairo_xlib_display_destroy (display);

    /* Return value in accordance with requirements of
     * XESetCloseDisplay */
    return 0;
}

cairo_status_t
_cairo_xlib_display_get (Display *dpy,
			 cairo_xlib_display_t **out)
{
    cairo_xlib_display_t *display;
    cairo_xlib_display_t **prev;
    XExtCodes *codes;
    const char *env;
    cairo_status_t status = CAIRO_STATUS_SUCCESS;

    /* There is an apparent deadlock between this mutex and the
     * mutex for the display, but it's actually safe. For the
     * app to call XCloseDisplay() while any other thread is
     * inside this function would be an error in the logic
     * app, and the CloseDisplay hook is the only other place we
     * acquire this mutex.
     */
    CAIRO_MUTEX_LOCK (_cairo_xlib_display_mutex);

    for (prev = &_cairo_xlib_display_list; (display = *prev); prev = &(*prev)->next)
    {
	if (display->display == dpy) {
	    /*
	     * MRU the list
	     */
	    if (prev != &_cairo_xlib_display_list) {
		*prev = display->next;
		display->next = _cairo_xlib_display_list;
		_cairo_xlib_display_list = display;
	    }
	    break;
	}
    }

    if (display != NULL) {
	display = _cairo_xlib_display_reference (display);
	goto UNLOCK;
    }

    display = malloc (sizeof (cairo_xlib_display_t));
    if (unlikely (display == NULL)) {
	status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
	goto UNLOCK;
    }

    /* Xlib calls out to the extension close_display hooks in LIFO
     * order. So we have to ensure that all extensions that we depend
     * on in our close_display hook are properly initialized before we
     * add our hook. For now, that means Render, so we call into its
     * QueryVersion function to ensure it gets initialized.
     */
    display->render_major = display->render_minor = -1;
    XRenderQueryVersion (dpy, &display->render_major, &display->render_minor);
    env = getenv ("CAIRO_DEBUG");
    if (env != NULL && (env = strstr (env, "xrender-version=")) != NULL) {
	int max_render_major, max_render_minor;

	env += sizeof ("xrender-version=") - 1;
	if (sscanf (env, "%d.%d", &max_render_major, &max_render_minor) != 2)
	    max_render_major = max_render_minor = -1;

	if (max_render_major < display->render_major ||
	    (max_render_major == display->render_major &&
	     max_render_minor < display->render_minor))
	{
	    display->render_major = max_render_major;
	    display->render_minor = max_render_minor;
	}
    }

    codes = XAddExtension (dpy);
    if (unlikely (codes == NULL)) {
	status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
	free (display);
	display = NULL;
	goto UNLOCK;
    }

    XESetCloseDisplay (dpy, codes->extension, _cairo_xlib_close_display);

    _cairo_freelist_init (&display->wq_freelist, sizeof (cairo_xlib_job_t));

    CAIRO_REFERENCE_COUNT_INIT (&display->ref_count, 2); /* add one for the CloseDisplay */
    CAIRO_MUTEX_INIT (display->mutex);
    display->display = dpy;
    display->screens = NULL;
    display->workqueue = NULL;
    display->close_display_hooks = NULL;
    display->closed = FALSE;

    memset (display->cached_xrender_formats, 0,
	    sizeof (display->cached_xrender_formats));

    /* Prior to Render 0.10, there is no protocol support for gradients and
     * we call function stubs instead, which would silently consume the drawing.
     */
#if RENDER_MAJOR == 0 && RENDER_MINOR < 10
    display->buggy_gradients = TRUE;
#else
    display->buggy_gradients = FALSE;
#endif
    display->buggy_pad_reflect = FALSE;
    display->buggy_repeat = FALSE;

    /* This buggy_repeat condition is very complicated because there
     * are multiple X server code bases (with multiple versioning
     * schemes within a code base), and multiple bugs.
     *
     * The X servers:
     *
     *    1. The Vendor=="XFree86" code base with release numbers such
     *    as 4.7.0 (VendorRelease==40700000).
     *
     *    2. The Vendor=="X.Org" code base (a descendant of the
     *    XFree86 code base). It originally had things like
     *    VendorRelease==60700000 for release 6.7.0 but then changed
     *    its versioning scheme so that, for example,
     *    VendorRelease==10400000 for the 1.4.0 X server within the
     *    X.Org 7.3 release.
     *
     * The bugs:
     *
     *    1. The original bug that led to the buggy_repeat
     *    workaround. This was a bug that Owen Taylor investigated,
     *    understood well, and characterized against carious X
     *    servers. Confirmed X servers with this bug include:
     *
     *		"XFree86" <= 40500000
     *		"X.Org" <= 60802000 (only with old numbering >= 60700000)
     *
     *    2. A separate bug resulting in a crash of the X server when
     *    using cairo's extend-reflect test case, (which, surprisingly
     *    enough was not passing RepeatReflect to the X server, but
     *    instead using RepeatNormal in a workaround). Nobody to date
     *    has understood the bug well, but it appears to be gone as of
     *    the X.Org 1.4.0 server. This bug is coincidentally avoided
     *    by using the same buggy_repeat workaround. Confirmed X
     *    servers with this bug include:
     *
     *		"X.org" == 60900000 (old versioning scheme)
     *		"X.org"  < 10400000 (new numbering scheme)
     *
     *    For the old-versioning-scheme X servers we don't know
     *    exactly when second the bug started, but since bug 1 is
     *    present through 6.8.2 and bug 2 is present in 6.9.0 it seems
     *    safest to just blacklist all old-versioning-scheme X servers,
     *    (just using VendorRelease < 70000000), as buggy_repeat=TRUE.
     */
    if (strstr (ServerVendor (dpy), "X.Org") != NULL) {
	if (VendorRelease (dpy) >= 60700000) {
	    if (VendorRelease (dpy) < 70000000)
		display->buggy_repeat = TRUE;

	    /* We know that gradients simply do not work in early Xorg servers */
	    if (VendorRelease (dpy) < 70200000)
		display->buggy_gradients = TRUE;

	    /* And the extended repeat modes were not fixed until much later */
	    display->buggy_pad_reflect = TRUE;
	} else {
	    if (VendorRelease (dpy) < 10400000)
		display->buggy_repeat = TRUE;

	    /* Too many bugs in the early drivers */
	    if (VendorRelease (dpy) < 10699000)
		display->buggy_pad_reflect = TRUE;
	}
    } else if (strstr (ServerVendor (dpy), "XFree86") != NULL) {
	if (VendorRelease (dpy) <= 40500000)
	    display->buggy_repeat = TRUE;

	display->buggy_gradients = TRUE;
	display->buggy_pad_reflect = TRUE;
    }

    display->next = _cairo_xlib_display_list;
    _cairo_xlib_display_list = display;

UNLOCK:
    CAIRO_MUTEX_UNLOCK (_cairo_xlib_display_mutex);
    *out = display;
    return status;
}

void
_cairo_xlib_add_close_display_hook (cairo_xlib_display_t	*display,
				    cairo_xlib_hook_t		*hook)
{
    CAIRO_MUTEX_LOCK (display->mutex);
    hook->prev = NULL;
    hook->next = display->close_display_hooks;
    if (hook->next != NULL)
	hook->next->prev = hook;
    display->close_display_hooks = hook;
    CAIRO_MUTEX_UNLOCK (display->mutex);
}

/* display->mutex must be held */
static void
_cairo_xlib_remove_close_display_hook_internal (cairo_xlib_display_t *display,
						cairo_xlib_hook_t *hook)
{
    if (display->close_display_hooks == hook)
	display->close_display_hooks = hook->next;
    else if (hook->prev != NULL)
	hook->prev->next = hook->next;

    if (hook->next != NULL)
	hook->next->prev = hook->prev;

    hook->prev = NULL;
    hook->next = NULL;
}

void
_cairo_xlib_remove_close_display_hook (cairo_xlib_display_t	*display,
				       cairo_xlib_hook_t	*hook)
{
    CAIRO_MUTEX_LOCK (display->mutex);
    _cairo_xlib_remove_close_display_hook_internal (display, hook);
    CAIRO_MUTEX_UNLOCK (display->mutex);
}

cairo_status_t
_cairo_xlib_display_queue_resource (cairo_xlib_display_t *display,
	                            cairo_xlib_notify_resource_func notify,
				    XID xid)
{
    cairo_xlib_job_t *job;
    cairo_status_t status = CAIRO_STATUS_NO_MEMORY;

    CAIRO_MUTEX_LOCK (display->mutex);
    if (display->closed == FALSE) {
	job = _cairo_freelist_alloc (&display->wq_freelist);
	if (job != NULL) {
	    job->type = RESOURCE;
	    job->func.resource.xid = xid;
	    job->func.resource.notify = notify;

	    job->next = display->workqueue;
	    display->workqueue = job;

	    status = CAIRO_STATUS_SUCCESS;
	}
    }
    CAIRO_MUTEX_UNLOCK (display->mutex);

    return status;
}

cairo_status_t
_cairo_xlib_display_queue_work (cairo_xlib_display_t *display,
	                        cairo_xlib_notify_func notify,
				void *data,
				void (*destroy) (void *))
{
    cairo_xlib_job_t *job;
    cairo_status_t status = CAIRO_STATUS_NO_MEMORY;

    CAIRO_MUTEX_LOCK (display->mutex);
    if (display->closed == FALSE) {
	job = _cairo_freelist_alloc (&display->wq_freelist);
	if (job != NULL) {
	    job->type = WORK;
	    job->func.work.data    = data;
	    job->func.work.notify  = notify;
	    job->func.work.destroy = destroy;

	    job->next = display->workqueue;
	    display->workqueue = job;

	    status = CAIRO_STATUS_SUCCESS;
	}
    }
    CAIRO_MUTEX_UNLOCK (display->mutex);

    return status;
}

void
_cairo_xlib_display_notify (cairo_xlib_display_t *display)
{
    cairo_xlib_job_t *jobs, *job, *freelist;
    Display *dpy = display->display;

    /* Optimistic atomic pointer read -- don't care if it is wrong due to
     * contention as we will check again very shortly.
     */
    if (display->workqueue == NULL)
	return;

    CAIRO_MUTEX_LOCK (display->mutex);
    jobs = display->workqueue;
    while (jobs != NULL) {
	display->workqueue = NULL;
	CAIRO_MUTEX_UNLOCK (display->mutex);

	/* reverse the list to obtain FIFO order */
	job = NULL;
	do {
	    cairo_xlib_job_t *next = jobs->next;
	    jobs->next = job;
	    job = jobs;
	    jobs = next;
	} while (jobs != NULL);
	freelist = jobs = job;

	do {
	    job = jobs;
	    jobs = job->next;

	    switch (job->type){
	    case WORK:
		job->func.work.notify (dpy, job->func.work.data);
		if (job->func.work.destroy != NULL)
		    job->func.work.destroy (job->func.work.data);
		break;

	    case RESOURCE:
		job->func.resource.notify (dpy, job->func.resource.xid);
		break;
	    }
	} while (jobs != NULL);

	CAIRO_MUTEX_LOCK (display->mutex);
	do {
	    job = freelist;
	    freelist = job->next;
	    _cairo_freelist_free (&display->wq_freelist, job);
	} while (freelist != NULL);

	jobs = display->workqueue;
    }
    CAIRO_MUTEX_UNLOCK (display->mutex);
}

XRenderPictFormat *
_cairo_xlib_display_get_xrender_format (cairo_xlib_display_t	*display,
	                                cairo_format_t		 format)
{
    XRenderPictFormat *xrender_format;

#if ! ATOMIC_OP_NEEDS_MEMORY_BARRIER
    xrender_format = display->cached_xrender_formats[format];
    if (likely (xrender_format != NULL))
	return xrender_format;
#endif

    CAIRO_MUTEX_LOCK (display->mutex);
    xrender_format = display->cached_xrender_formats[format];
    if (xrender_format == NULL) {
	int pict_format;

	switch (format) {
	case CAIRO_FORMAT_A1:
	    pict_format = PictStandardA1; break;
	case CAIRO_FORMAT_A8:
	    pict_format = PictStandardA8; break;
	case CAIRO_FORMAT_RGB24:
	    pict_format = PictStandardRGB24; break;
	default:
	    ASSERT_NOT_REACHED;
	case CAIRO_FORMAT_ARGB32:
	    pict_format = PictStandardARGB32; break;
	}
	xrender_format = XRenderFindStandardFormat (display->display,
		                                    pict_format);
	display->cached_xrender_formats[format] = xrender_format;
    }
    CAIRO_MUTEX_UNLOCK (display->mutex);

    return xrender_format;
}

Display *
_cairo_xlib_display_get_dpy (cairo_xlib_display_t *display)
{
    return display->display;
}

void
_cairo_xlib_display_remove_screen (cairo_xlib_display_t *display,
				   cairo_xlib_screen_t *screen)
{
    cairo_xlib_screen_t **prev;
    cairo_xlib_screen_t *list;

    CAIRO_MUTEX_LOCK (display->mutex);
    for (prev = &display->screens; (list = *prev); prev = &list->next) {
	if (list == screen) {
	    *prev = screen->next;
	    break;
	}
    }
    CAIRO_MUTEX_UNLOCK (display->mutex);
}

cairo_status_t
_cairo_xlib_display_get_screen (cairo_xlib_display_t *display,
				Screen *screen,
				cairo_xlib_screen_t **out)
{
    cairo_xlib_screen_t *info = NULL, **prev;

    CAIRO_MUTEX_LOCK (display->mutex);
    if (display->closed) {
	CAIRO_MUTEX_UNLOCK (display->mutex);
	return _cairo_error (CAIRO_STATUS_SURFACE_FINISHED);
    }

    for (prev = &display->screens; (info = *prev); prev = &(*prev)->next) {
	if (info->screen == screen) {
	    /*
	     * MRU the list
	     */
	    if (prev != &display->screens) {
		*prev = info->next;
		info->next = display->screens;
		display->screens = info;
	    }
	    break;
	}
    }
    CAIRO_MUTEX_UNLOCK (display->mutex);

    *out = info;
    return CAIRO_STATUS_SUCCESS;
}


void
_cairo_xlib_display_add_screen (cairo_xlib_display_t *display,
				cairo_xlib_screen_t *screen)
{
    CAIRO_MUTEX_LOCK (display->mutex);
    screen->next = display->screens;
    display->screens = screen;
    CAIRO_MUTEX_UNLOCK (display->mutex);
}

void
_cairo_xlib_display_get_xrender_version (cairo_xlib_display_t *display,
					 int *major, int *minor)
{
    *major = display->render_major;
    *minor = display->render_minor;
}

cairo_bool_t
_cairo_xlib_display_has_repeat (cairo_xlib_display_t *display)
{
    return ! display->buggy_repeat;
}

cairo_bool_t
_cairo_xlib_display_has_reflect (cairo_xlib_display_t *display)
{
    return ! display->buggy_pad_reflect;
}

cairo_bool_t
_cairo_xlib_display_has_gradients (cairo_xlib_display_t *display)
{
    return ! display->buggy_gradients;
}