xcb: Refresh.

Still an experimental backend, it's now a little too late to stabilise
for 1.10, but this should represent a major step forward in its feature
set and an attempt to catch up with all the bug fixes that have been
performed on xlib. Notably not tested yet (and expected to be broken)
are mixed-endian connections and low bitdepth servers (the dithering
support has not been copied over for instance). However, it seems robust
enough for daily use...

Of particular note in this update is that the xcb surface is now capable
of subverting the xlib surface through the ./configure --enable-xlib-xcb
option. This replaces the xlib surface with a proxy that forwards all
operations to an equivalent xcb surface whilst preserving the cairo-xlib
API that is required for compatibility with the existing applications,
for instance GTK+ and Mozilla. Also you can experiment with enabling a
DRM bypass, though you need to be extremely foolhardy to do so.

1 files changed, 867 insertions, 0 deletions

diff --git a/src/cairo-xcb-connection.c b/src/cairo-xcb-connection.c
new file mode 100644
index 00000000..6721e923
--- /dev/null
+++ b/src/cairo-xcb-connection.c
@@ -0,0 +1,867 @@
+/* Cairo - a vector graphics library with display and print output
+ *
+ * Copyright © 2009 Intel Corporation
+ *
+ * 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.
+ *
+ * Authors:
+ *    Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+
+#include "cairoint.h"
+
+#include "cairo-xcb-private.h"
+#include "cairo-hash-private.h"
+#include "cairo-freelist-private.h"
+#include "cairo-list-private.h"
+
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <xcb/xcbext.h>
+#include <xcb/bigreq.h>
+#include <xcb/dri2.h>
+#include <xcb/shm.h>
+#include <errno.h>
+
+typedef struct _cairo_xcb_xrender_format {
+    cairo_hash_entry_t key;
+    xcb_render_pictformat_t xrender_format;
+} cairo_xcb_xrender_format_t;
+
+typedef struct _cairo_xcb_xid {
+    cairo_list_t link;
+    uint32_t xid;
+} cairo_xcb_xid_t;
+
+#define XCB_RENDER_AT_LEAST(V, major, minor)	\
+	(((V)->major_version > major) ||			\
+	 (((V)->major_version == major) && ((V)->minor_version >= minor)))
+
+#define XCB_RENDER_HAS_CREATE_PICTURE(surface)		XCB_RENDER_AT_LEAST((surface), 0, 0)
+#define XCB_RENDER_HAS_COMPOSITE(surface)		XCB_RENDER_AT_LEAST((surface), 0, 0)
+#define XCB_RENDER_HAS_COMPOSITE_TEXT(surface)		XCB_RENDER_AT_LEAST((surface), 0, 0)
+
+#define XCB_RENDER_HAS_FILL_RECTANGLES(surface)		XCB_RENDER_AT_LEAST((surface), 0, 1)
+
+#define XCB_RENDER_HAS_DISJOINT(surface)		XCB_RENDER_AT_LEAST((surface), 0, 2)
+#define XCB_RENDER_HAS_CONJOINT(surface)		XCB_RENDER_AT_LEAST((surface), 0, 2)
+
+#define XCB_RENDER_HAS_TRAPEZOIDS(surface)		XCB_RENDER_AT_LEAST((surface), 0, 4)
+#define XCB_RENDER_HAS_TRIANGLES(surface)		XCB_RENDER_AT_LEAST((surface), 0, 4)
+#define XCB_RENDER_HAS_TRISTRIP(surface)		XCB_RENDER_AT_LEAST((surface), 0, 4)
+#define XCB_RENDER_HAS_TRIFAN(surface)			XCB_RENDER_AT_LEAST((surface), 0, 4)
+#define XCB_RENDER_HAS_SPANS(surface)			XCB_RENDER_AT_LEAST((surface), 0, 12)
+
+#define XCB_RENDER_HAS_PICTURE_TRANSFORM(surface)	XCB_RENDER_AT_LEAST((surface), 0, 6)
+#define XCB_RENDER_HAS_FILTERS(surface)			XCB_RENDER_AT_LEAST((surface), 0, 6)
+
+#define XCB_RENDER_HAS_EXTENDED_REPEAT(surface)	XCB_RENDER_AT_LEAST((surface), 0, 10)
+#define XCB_RENDER_HAS_GRADIENTS(surface)	XCB_RENDER_AT_LEAST((surface), 0, 10)
+
+#define XCB_RENDER_HAS_PDF_OPERATORS(surface)	XCB_RENDER_AT_LEAST((surface), 0, 11)
+
+static cairo_list_t connections;
+
+static cairo_status_t
+_cairo_xcb_connection_find_visual_formats (cairo_xcb_connection_t *connection,
+					  const xcb_render_query_pict_formats_reply_t *formats)
+{
+    xcb_render_pictscreen_iterator_t screens;
+    xcb_render_pictdepth_iterator_t depths;
+    xcb_render_pictvisual_iterator_t visuals;
+
+    for (screens = xcb_render_query_pict_formats_screens_iterator (formats);
+	 screens.rem;
+	 xcb_render_pictscreen_next (&screens))
+    {
+	for (depths = xcb_render_pictscreen_depths_iterator (screens.data);
+	     depths.rem;
+	     xcb_render_pictdepth_next (&depths))
+	{
+	    for (visuals = xcb_render_pictdepth_visuals_iterator (depths.data);
+		 visuals.rem;
+		 xcb_render_pictvisual_next (&visuals))
+	    {
+		cairo_xcb_xrender_format_t *f;
+		cairo_status_t status;
+
+		f = malloc (sizeof (cairo_xcb_xrender_format_t));
+		if (unlikely (f == NULL))
+		    return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+
+		f->key.hash = visuals.data->visual;
+		f->xrender_format = visuals.data->format;
+		status = _cairo_hash_table_insert (connection->visual_to_xrender_format,
+						   &f->key);
+		if (unlikely (status))
+		    return status;
+	    }
+	}
+    }
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+#if 0
+static xcb_format_t *
+find_format_for_depth (const xcb_setup_t *setup, uint8_t depth)
+{
+    xcb_format_t *fmt = xcb_setup_pixmap_formats (setup);
+    xcb_format_t *fmtend = fmt + xcb_setup_pixmap_formats_length (setup);
+
+    for (; fmt != fmtend; ++fmt)
+	if (fmt->depth == depth)
+	    return fmt;
+
+    return 0;
+}
+#endif
+
+static cairo_status_t
+_cairo_xcb_connection_parse_xrender_formats (cairo_xcb_connection_t *connection,
+					     const xcb_render_query_pict_formats_reply_t *formats)
+{
+    xcb_render_pictforminfo_iterator_t i;
+    cairo_status_t status;
+
+    for (i = xcb_render_query_pict_formats_formats_iterator (formats);
+	 i.rem;
+	 xcb_render_pictforminfo_next (&i))
+    {
+	cairo_format_masks_t masks;
+	pixman_format_code_t pixman_format;
+
+	if (i.data->type != XCB_RENDER_PICT_TYPE_DIRECT)
+	    continue;
+
+	masks.alpha_mask =
+	    (unsigned long) i.data->direct.alpha_mask << i.data->direct.alpha_shift;
+	masks.red_mask =
+	    (unsigned long) i.data->direct.red_mask << i.data->direct.red_shift;
+	masks.green_mask =
+	    (unsigned long) i.data->direct.green_mask << i.data->direct.green_shift;
+	masks.blue_mask =
+	    (unsigned long) i.data->direct.blue_mask << i.data->direct.blue_shift;
+	masks.bpp = i.data->depth;
+
+	if (_pixman_format_from_masks (&masks, &pixman_format)) {
+	    cairo_hash_entry_t key;
+
+	    key.hash = pixman_format;
+	    if (! _cairo_hash_table_lookup (connection->xrender_formats, &key)) {
+		cairo_xcb_xrender_format_t *f;
+
+		f = malloc (sizeof (cairo_xcb_xrender_format_t));
+		if (unlikely (f == NULL))
+		    return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+
+		f->key.hash = pixman_format;
+		f->xrender_format = i.data->id;
+		status = _cairo_hash_table_insert (connection->xrender_formats,
+						   &f->key);
+		if (unlikely (status))
+		    return status;
+
+#if 0
+		printf ("xrender %x -> (%lx, %lx, %lx, %lx, %d) %x [%d, %d]\n",
+			i.data->id,
+			masks.alpha_mask,
+			masks.red_mask,
+			masks.green_mask,
+			masks.blue_mask,
+			masks.bpp,
+			pixman_format,
+			PIXMAN_FORMAT_DEPTH(pixman_format),
+			PIXMAN_FORMAT_BPP(pixman_format));
+#endif
+	    }
+	}
+    }
+
+    status = _cairo_xcb_connection_find_visual_formats (connection, formats);
+    if (unlikely (status))
+	return status;
+
+    connection->standard_formats[CAIRO_FORMAT_A1] =
+	_cairo_xcb_connection_get_xrender_format (connection, PIXMAN_a1);
+
+    connection->standard_formats[CAIRO_FORMAT_A8] =
+	_cairo_xcb_connection_get_xrender_format (connection, PIXMAN_a8);
+
+    connection->standard_formats[CAIRO_FORMAT_RGB24] =
+	_cairo_xcb_connection_get_xrender_format (connection,
+						  PIXMAN_FORMAT (24,
+								 PIXMAN_TYPE_ARGB,
+								 0, 8, 8, 8));
+    if (connection->standard_formats[CAIRO_FORMAT_RGB24] == XCB_NONE) {
+	connection->standard_formats[CAIRO_FORMAT_RGB24] =
+	    _cairo_xcb_connection_get_xrender_format (connection,
+						      PIXMAN_FORMAT (24, PIXMAN_TYPE_ABGR,
+								     0, 8, 8, 8));
+    }
+
+    connection->standard_formats[CAIRO_FORMAT_ARGB32] =
+	_cairo_xcb_connection_get_xrender_format (connection, PIXMAN_a8r8g8b8);
+    if (connection->standard_formats[CAIRO_FORMAT_ARGB32] == XCB_NONE) {
+	connection->standard_formats[CAIRO_FORMAT_ARGB32] =
+	    _cairo_xcb_connection_get_xrender_format (connection, PIXMAN_a8b8g8r8);
+    }
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+/*
+ * We require support for depth 1, 8, 24 and 32 pixmaps
+ */
+#define DEPTH_MASK(d)	(1 << ((d) - 1))
+#define REQUIRED_DEPTHS	(DEPTH_MASK(1) | \
+			 DEPTH_MASK(8) | \
+			 DEPTH_MASK(24) | \
+			 DEPTH_MASK(32))
+static cairo_bool_t
+pixmap_depths_usable (cairo_xcb_connection_t *connection,
+		      uint32_t missing,
+		      xcb_drawable_t root)
+{
+    xcb_connection_t *c = connection->xcb_connection;
+    xcb_void_cookie_t create_cookie[32];
+    xcb_pixmap_t pixmap;
+    cairo_bool_t success = TRUE;
+    int depth, i, j;
+
+    pixmap = _cairo_xcb_connection_get_xid (connection);
+
+    for (depth = 1, i = 0; depth <= 32; depth++) {
+	if (missing & DEPTH_MASK(depth)) {
+	    create_cookie[i] = xcb_create_pixmap_checked (c, depth, pixmap, root, 1, 1);
+	    xcb_free_pixmap (c, pixmap);
+	    if (!create_cookie[i].sequence) {
+		success = FALSE;
+		break;
+	    }
+	    i++;
+	}
+    }
+
+    for (j = 0; j < i; j++) {
+	xcb_generic_error_t *create_error = xcb_request_check (c, create_cookie[j]);
+	success &= create_error == NULL;
+	free (create_error);
+    }
+
+    _cairo_xcb_connection_put_xid (connection, pixmap);
+
+    return success;
+}
+
+static cairo_bool_t
+has_required_depths (cairo_xcb_connection_t *connection)
+{
+    xcb_screen_iterator_t screens;
+
+    for (screens = xcb_setup_roots_iterator (connection->root);
+	 screens.rem;
+	 xcb_screen_next (&screens))
+    {
+	xcb_depth_iterator_t depths;
+	uint32_t missing = REQUIRED_DEPTHS;
+
+	for (depths = xcb_screen_allowed_depths_iterator (screens.data);
+	     depths.rem;
+	     xcb_depth_next (&depths))
+	{
+	    missing &= ~DEPTH_MASK (depths.data->depth);
+	}
+	if (missing == 0)
+	    continue;
+
+	/*
+	 * Ok, this is ugly.  It should be sufficient at this
+	 * point to just return false, but Xinerama is broken at
+	 * this point and only advertises depths which have an
+	 * associated visual.  Of course, the other depths still
+	 * work, but the only way to find out is to try them.
+	 */
+	if (! pixmap_depths_usable (connection, missing, screens.data->root))
+	    return FALSE;
+    }
+
+    return TRUE;
+}
+
+static cairo_status_t
+_cairo_xcb_connection_query_render (cairo_xcb_connection_t *connection)
+{
+    xcb_connection_t *c = connection->xcb_connection;
+    xcb_render_query_version_cookie_t version_cookie;
+    xcb_render_query_pict_formats_cookie_t formats_cookie;
+    xcb_render_query_version_reply_t *version;
+    xcb_render_query_pict_formats_reply_t *formats;
+    cairo_status_t status;
+    cairo_bool_t present;
+
+    version_cookie = xcb_render_query_version (c, 0, 10);
+    formats_cookie = xcb_render_query_pict_formats (c);
+
+    present = has_required_depths (connection);
+    version = xcb_render_query_version_reply (c, version_cookie, 0);
+    formats = xcb_render_query_pict_formats_reply (c, formats_cookie, 0);
+    if (! present || version == NULL || formats == NULL) {
+	free (version);
+	free (formats);
+	return CAIRO_STATUS_SUCCESS;
+    }
+
+    /* always true if the extension is present (i.e. >= 0.0) */
+    connection->flags |= CAIRO_XCB_HAS_RENDER;
+    connection->flags |= CAIRO_XCB_RENDER_HAS_COMPOSITE;
+    connection->flags |= CAIRO_XCB_RENDER_HAS_COMPOSITE_GLYPHS;
+
+    if (XCB_RENDER_HAS_FILL_RECTANGLES (version))
+	connection->flags |= CAIRO_XCB_RENDER_HAS_FILL_RECTANGLES;
+
+    if (XCB_RENDER_HAS_TRAPEZOIDS (version))
+	connection->flags |= CAIRO_XCB_RENDER_HAS_COMPOSITE_TRAPEZOIDS;
+
+    if (XCB_RENDER_HAS_PICTURE_TRANSFORM (version))
+	connection->flags |= CAIRO_XCB_RENDER_HAS_PICTURE_TRANSFORM;
+
+    if (XCB_RENDER_HAS_FILTERS (version))
+	connection->flags |= CAIRO_XCB_RENDER_HAS_FILTERS;
+
+    if (XCB_RENDER_HAS_PDF_OPERATORS (version))
+	connection->flags |= CAIRO_XCB_RENDER_HAS_PDF_OPERATORS;
+
+    if (XCB_RENDER_HAS_EXTENDED_REPEAT (version))
+	connection->flags |= CAIRO_XCB_RENDER_HAS_EXTENDED_REPEAT;
+
+    if (XCB_RENDER_HAS_GRADIENTS (version))
+	connection->flags |= CAIRO_XCB_RENDER_HAS_GRADIENTS;
+
+    free (version);
+
+    status = _cairo_xcb_connection_parse_xrender_formats (connection, formats);
+    free (formats);
+
+    return status;
+}
+
+#if 0
+static void
+_cairo_xcb_connection_query_cairo (cairo_xcb_connection_t *connection)
+{
+    xcb_connection_t *c = connection->xcb_connection;
+    xcb_cairo_query_version_reply_t *version;
+
+    version = xcb_cairo_query_version_reply (c,
+					     xcb_cairo_query_version (c, 0, 0),
+					     0);
+
+    free (version);
+}
+#endif
+
+static cairo_bool_t
+can_use_shm (cairo_xcb_connection_t *connection)
+{
+    cairo_bool_t success = TRUE;
+    xcb_connection_t *c = connection->xcb_connection;
+    xcb_void_cookie_t cookie[2];
+    xcb_generic_error_t *error;
+    int shmid;
+    uint32_t shmseg;
+    void *ptr;
+
+    shmid = shmget (IPC_PRIVATE, 0x1000, IPC_CREAT | 0600);
+    if (shmid == -1)
+	return FALSE;
+
+    ptr = shmat (shmid, NULL, 0);
+    if (ptr == (char *) -1) {
+	shmctl (shmid, IPC_RMID, NULL);
+	return FALSE;
+    }
+
+    shmseg = _cairo_xcb_connection_get_xid (connection);
+    cookie[0] = xcb_shm_attach_checked (c, shmseg, shmid, FALSE);
+    cookie[1] = xcb_shm_detach_checked (c, shmseg);
+    _cairo_xcb_connection_put_xid (connection, shmseg);
+
+    error = xcb_request_check (c, cookie[0]);
+    if (error != NULL)
+	success = FALSE;
+
+    error = xcb_request_check (c, cookie[1]);
+    if (error != NULL)
+	success = FALSE;
+
+    shmctl (shmid, IPC_RMID, NULL);
+    shmdt (ptr);
+
+    return success;
+}
+
+static void
+_cairo_xcb_connection_query_shm (cairo_xcb_connection_t *connection)
+{
+    xcb_connection_t *c = connection->xcb_connection;
+    xcb_shm_query_version_reply_t *version;
+
+    version = xcb_shm_query_version_reply (c, xcb_shm_query_version (c), 0);
+    if (version == NULL)
+	return;
+
+    free (version);
+
+    if (can_use_shm (connection))
+	connection->flags |= CAIRO_XCB_HAS_SHM;
+}
+
+#if CAIRO_HAS_XCB_DRM_FUNCTIONS
+static void
+_cairo_xcb_connection_query_dri2 (cairo_xcb_connection_t *connection)
+{
+    xcb_connection_t *c = connection->xcb_connection;
+    xcb_dri2_query_version_reply_t *version;
+
+    version = xcb_dri2_query_version_reply (c,
+					    xcb_dri2_query_version (c,
+								    XCB_DRI2_MAJOR_VERSION,
+								    XCB_DRI2_MINOR_VERSION),
+					    0);
+    if (version == NULL)
+	return;
+
+    free (version);
+
+    connection->flags |= CAIRO_XCB_HAS_DRI2;
+}
+#endif
+
+static void
+_device_flush (void *device)
+{
+    cairo_xcb_connection_t *connection = device;
+    cairo_xcb_screen_t *screen;
+    cairo_status_t status;
+
+    status = cairo_device_acquire (&connection->device);
+    if (unlikely (status))
+	return;
+
+    CAIRO_MUTEX_LOCK (connection->screens_mutex);
+    cairo_list_foreach_entry (screen, cairo_xcb_screen_t,
+			      &connection->screens, link)
+    {
+	if (screen->device != NULL)
+	    cairo_device_flush (screen->device);
+    }
+    CAIRO_MUTEX_UNLOCK (connection->screens_mutex);
+
+    xcb_flush (connection->xcb_connection);
+
+    cairo_device_release (&connection->device);
+}
+
+static cairo_bool_t
+_xrender_formats_equal (const void *A, const void *B)
+{
+    const cairo_xcb_xrender_format_t *a = A, *b = B;
+    return a->key.hash == b->key.hash;
+}
+
+static void
+_pluck_xrender_format (void *entry,
+		       void *closure)
+{
+    _cairo_hash_table_remove (closure, entry);
+    free (entry);
+}
+
+static void
+_device_finish (void *device)
+{
+    cairo_xcb_connection_t *connection = device;
+
+    if (! cairo_list_is_empty (&connection->link)) {
+	CAIRO_MUTEX_LOCK (_cairo_xcb_connections_mutex);
+	cairo_list_del (&connection->link);
+	CAIRO_MUTEX_UNLOCK (_cairo_xcb_connections_mutex);
+    }
+
+    while (! cairo_list_is_empty (&connection->fonts)) {
+	cairo_xcb_font_t *font;
+
+	font = cairo_list_first_entry (&connection->fonts,
+				       cairo_xcb_font_t,
+				       link);
+	_cairo_xcb_font_finish (font);
+    }
+
+    while (! cairo_list_is_empty (&connection->screens)) {
+	cairo_xcb_screen_t *screen;
+
+	screen = cairo_list_first_entry (&connection->screens,
+					 cairo_xcb_screen_t,
+					 link);
+	_cairo_xcb_screen_finish (screen);
+    }
+}
+
+static void
+_device_destroy (void *device)
+{
+    cairo_xcb_connection_t *connection = device;
+
+    _cairo_hash_table_foreach (connection->xrender_formats,
+			       _pluck_xrender_format, connection->xrender_formats);
+    _cairo_hash_table_destroy (connection->xrender_formats);
+
+    _cairo_hash_table_foreach (connection->visual_to_xrender_format,
+			       _pluck_xrender_format,
+			       connection->visual_to_xrender_format);
+    _cairo_hash_table_destroy (connection->visual_to_xrender_format);
+
+    _cairo_xcb_connection_shm_mem_pools_fini (connection);
+    _cairo_freepool_fini (&connection->shm_info_freelist);
+
+    _cairo_freepool_fini (&connection->xid_pool);
+
+    CAIRO_MUTEX_FINI (connection->shm_mutex);
+    CAIRO_MUTEX_FINI (connection->screens_mutex);
+
+    free (connection);
+}
+
+static const cairo_device_backend_t _cairo_xcb_device_backend = {
+    CAIRO_DEVICE_TYPE_XCB,
+
+    NULL, NULL, /* lock, unlock */
+
+    _device_flush,
+    _device_finish,
+    _device_destroy,
+};
+
+cairo_xcb_connection_t *
+_cairo_xcb_connection_get (xcb_connection_t *xcb_connection)
+{
+    cairo_xcb_connection_t *connection;
+    const xcb_query_extension_reply_t *ext;
+    cairo_status_t status;
+
+    CAIRO_MUTEX_LOCK (_cairo_xcb_connections_mutex);
+    if (connections.next == NULL) {
+	/* XXX _cairo_init () */
+	cairo_list_init (&connections);
+    }
+
+    cairo_list_foreach_entry (connection,
+			      cairo_xcb_connection_t,
+			      &connections,
+			      link)
+    {
+	if (connection->xcb_connection == xcb_connection) {
+	    /* Maintain MRU order. */
+	    if (connections.next != &connection->link)
+		cairo_list_move (&connection->link, &connections);
+
+	    goto unlock;
+	}
+    }
+
+    connection = malloc (sizeof (cairo_xcb_connection_t));
+    if (unlikely (connection == NULL))
+	goto unlock;
+
+    _cairo_device_init (&connection->device, &_cairo_xcb_device_backend);
+    CAIRO_MUTEX_INIT (connection->shm_mutex);
+    CAIRO_MUTEX_INIT (connection->screens_mutex);
+
+    connection->xcb_connection = xcb_connection;
+    connection->has_socket = FALSE;
+
+    xcb_prefetch_extension_data (xcb_connection, &xcb_big_requests_id);
+    xcb_prefetch_extension_data (xcb_connection, &xcb_shm_id);
+    xcb_prefetch_extension_data (xcb_connection, &xcb_render_id);
+#if 0
+    xcb_prefetch_extension_data (xcb_connection, &xcb_cairo_id);
+#endif
+#if CAIRO_HAS_XCB_DRM_FUNCTIONS
+    xcb_prefetch_extension_data (xcb_connection, &xcb_dri2_id);
+#endif
+
+    xcb_prefetch_maximum_request_length (xcb_connection);
+
+    cairo_list_init (&connection->fonts);
+    cairo_list_init (&connection->screens);
+    cairo_list_add (&connection->link, &connections);
+    connection->xrender_formats = _cairo_hash_table_create (_xrender_formats_equal);
+    connection->visual_to_xrender_format = _cairo_hash_table_create (_xrender_formats_equal);
+
+    cairo_list_init (&connection->free_xids);
+    _cairo_freepool_init (&connection->xid_pool,
+			  sizeof (cairo_xcb_xid_t));
+
+    cairo_list_init (&connection->shm_pools);
+    _cairo_freepool_init (&connection->shm_info_freelist,
+			  sizeof (cairo_xcb_shm_info_t));
+
+    connection->maximum_request_length =
+	xcb_get_maximum_request_length (xcb_connection);
+
+    connection->flags = 0;
+
+    connection->root = xcb_get_setup (xcb_connection);
+    connection->render = NULL;
+    ext = xcb_get_extension_data (xcb_connection, &xcb_render_id);
+    if (ext != NULL && ext->present) {
+	status = _cairo_xcb_connection_query_render (connection);
+	if (unlikely (status)) {
+	    _cairo_xcb_connection_destroy (connection);
+	    connection = NULL;
+	    goto unlock;
+	}
+
+	connection->render = ext;
+    }
+
+#if 0
+    ext = xcb_get_extension_data (connection, &xcb_cairo_id);
+    if (ext != NULL && ext->present)
+	_cairo_xcb_connection_query_cairo (connection);
+#endif
+
+    connection->shm = NULL;
+    ext = xcb_get_extension_data (xcb_connection, &xcb_shm_id);
+    if (ext != NULL && ext->present) {
+	_cairo_xcb_connection_query_shm (connection);
+	connection->shm = ext;
+    }
+
+    connection->dri2 = NULL;
+#if CAIRO_HAS_XCB_DRM_FUNCTIONS
+    ext = xcb_get_extension_data (xcb_connection, &xcb_dri2_id);
+    if (ext != NULL && ext->present) {
+	_cairo_xcb_connection_query_dri2 (connection);
+	connection->dri2 = ext;
+    }
+#endif
+
+unlock:
+    CAIRO_MUTEX_UNLOCK (_cairo_xcb_connections_mutex);
+
+    return connection;
+}
+
+xcb_render_pictformat_t
+_cairo_xcb_connection_get_xrender_format (cairo_xcb_connection_t *connection,
+					  pixman_format_code_t pixman_format)
+{
+    cairo_hash_entry_t key;
+    cairo_xcb_xrender_format_t *format;
+
+    key.hash = pixman_format;
+    format = _cairo_hash_table_lookup (connection->xrender_formats, &key);
+    return format ? format->xrender_format : XCB_NONE;
+}
+
+xcb_render_pictformat_t
+_cairo_xcb_connection_get_xrender_format_for_visual (cairo_xcb_connection_t *connection,
+						     const xcb_visualid_t visual)
+{
+    cairo_hash_entry_t key;
+    cairo_xcb_xrender_format_t *format;
+
+    key.hash = visual;
+    format = _cairo_hash_table_lookup (connection->visual_to_xrender_format, &key);
+    return format ? format->xrender_format : XCB_NONE;
+}
+
+void
+_cairo_xcb_connection_put_xid (cairo_xcb_connection_t *connection,
+			       uint32_t xid)
+{
+    cairo_xcb_xid_t *cache;
+
+    assert (CAIRO_MUTEX_IS_LOCKED (connection->mutex));
+    cache = _cairo_freepool_alloc (&connection->xid_pool);
+    if (likely (cache != NULL)) {
+	cache->xid = xid;
+	cairo_list_add (&cache->link, &connection->free_xids);
+    }
+}
+
+uint32_t
+_cairo_xcb_connection_get_xid (cairo_xcb_connection_t *connection)
+{
+    uint32_t xid;
+
+    assert (CAIRO_MUTEX_IS_LOCKED (connection->mutex));
+    if (! cairo_list_is_empty (&connection->free_xids)) {
+	cairo_xcb_xid_t *cache;
+
+	cache = cairo_list_first_entry (&connection->free_xids,
+					cairo_xcb_xid_t,
+					link);
+	xid = cache->xid;
+
+	cairo_list_del (&cache->link);
+	_cairo_freepool_free (&connection->xid_pool, cache);
+    } else {
+	xid = xcb_generate_id (connection->xcb_connection);
+    }
+
+    return xid;
+}
+
+static void
+_cairo_xcb_return_socket (void *closure)
+{
+    cairo_xcb_connection_t *connection = closure;
+
+    CAIRO_MUTEX_LOCK (connection->device.mutex);
+    connection->has_socket = FALSE;
+    CAIRO_MUTEX_UNLOCK (connection->device.mutex);
+}
+
+cairo_status_t
+_cairo_xcb_connection_take_socket (cairo_xcb_connection_t *connection)
+{
+    assert (CAIRO_MUTEX_IS_LOCKED (connection->mutex));
+
+    if (unlikely (connection->device.status))
+	return connection->device.status;
+
+    if (! connection->has_socket) {
+	if (! xcb_take_socket (connection->xcb_connection,
+			       _cairo_xcb_return_socket,
+			       connection,
+			       0, &connection->seqno))
+	{
+	    return connection->device.status = _cairo_error (CAIRO_STATUS_WRITE_ERROR);
+	}
+
+	connection->has_socket = TRUE;
+    }
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
+/* public (debug) interface */
+
+void
+cairo_xcb_device_debug_cap_xshm_version (cairo_device_t *device,
+                                         int major_version,
+                                         int minor_version)
+{
+    cairo_xcb_connection_t *connection = (cairo_xcb_connection_t *) device;
+    cairo_status_t status;
+
+    if (device->backend->type != CAIRO_DEVICE_TYPE_XCB) {
+	status = _cairo_device_set_error (device, CAIRO_STATUS_DEVICE_TYPE_MISMATCH);
+	return;
+    }
+
+    /* clear any flags that are inappropriate for the desired version */
+    if (major_version < 0 && minor_version < 0) {
+	connection->flags &= ~(CAIRO_XCB_HAS_SHM);
+    }
+}
+
+void
+cairo_xcb_device_debug_cap_xrender_version (cairo_device_t *device,
+                                            int major_version,
+                                            int minor_version)
+{
+    cairo_xcb_connection_t *connection = (cairo_xcb_connection_t *) device;
+    cairo_status_t status;
+
+    if (device->backend->type != CAIRO_DEVICE_TYPE_XCB) {
+	status = _cairo_device_set_error (device, CAIRO_STATUS_DEVICE_TYPE_MISMATCH);
+	return;
+    }
+
+    /* clear any flags that are inappropriate for the desired version */
+    if (major_version < 0 && minor_version < 0) {
+	connection->flags &= ~(CAIRO_XCB_HAS_RENDER |
+			       CAIRO_XCB_RENDER_HAS_COMPOSITE |
+			       CAIRO_XCB_RENDER_HAS_COMPOSITE_GLYPHS |
+			       CAIRO_XCB_RENDER_HAS_FILL_RECTANGLES |
+			       CAIRO_XCB_RENDER_HAS_COMPOSITE_TRAPEZOIDS |
+			       CAIRO_XCB_RENDER_HAS_PICTURE_TRANSFORM |
+			       CAIRO_XCB_RENDER_HAS_FILTERS |
+			       CAIRO_XCB_RENDER_HAS_PDF_OPERATORS |
+			       CAIRO_XCB_RENDER_HAS_EXTENDED_REPEAT |
+			       CAIRO_XCB_RENDER_HAS_GRADIENTS);
+    } else {
+	xcb_render_query_version_reply_t version;
+
+	version.major_version = major_version;
+	version.minor_version = minor_version;
+
+	if (! XCB_RENDER_HAS_FILL_RECTANGLES (&version))
+	    connection->flags &= ~CAIRO_XCB_RENDER_HAS_FILL_RECTANGLES;
+
+	if (! XCB_RENDER_HAS_TRAPEZOIDS (&version))
+	    connection->flags &= ~CAIRO_XCB_RENDER_HAS_COMPOSITE_TRAPEZOIDS;
+
+	if (! XCB_RENDER_HAS_PICTURE_TRANSFORM (&version))
+	    connection->flags &= ~CAIRO_XCB_RENDER_HAS_PICTURE_TRANSFORM;
+
+	if (! XCB_RENDER_HAS_FILTERS (&version))
+	    connection->flags &= ~CAIRO_XCB_RENDER_HAS_FILTERS;
+
+	if (! XCB_RENDER_HAS_PDF_OPERATORS (&version))
+	    connection->flags &= ~CAIRO_XCB_RENDER_HAS_PDF_OPERATORS;
+
+	if (! XCB_RENDER_HAS_EXTENDED_REPEAT (&version))
+	    connection->flags &= ~CAIRO_XCB_RENDER_HAS_EXTENDED_REPEAT;
+
+	if (! XCB_RENDER_HAS_GRADIENTS (&version))
+	    connection->flags &= ~CAIRO_XCB_RENDER_HAS_GRADIENTS;
+    }
+}
+
+#if 0
+void
+cairo_xcb_device_debug_cap_xcairo_version (cairo_device_t *device,
+                                           int major_version,
+                                           int minor_version)
+{
+    cairo_xcb_connection_t *connection = (cairo_xcb_connection_t *) device;
+    cairo_status_t status;
+
+    if (device->backend->type != CAIRO_DEVICE_TYPE_XCB) {
+	status = _cairo_device_set_error (device, CAIRO_STATUS_DEVICE_TYPE_MISMATCH);
+	return;
+    }
+
+    /* clear any flags that are inappropriate for the desired version */
+    if (major_version < 0 && minor_version < 0) {
+	connection->flags &= ~(CAIRO_XCB_HAS_CAIRO);
+    }
+}
+#endif