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-rw-r--r--src/cairo-xcb-shm.c337
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diff --git a/src/cairo-xcb-shm.c b/src/cairo-xcb-shm.c
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+/* Cairo - a vector graphics library with display and print output
+ *
+ * Copyright © 2007 Chris Wilson
+ * 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., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, 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 Red Hat, Inc.
+ *
+ * Contributors(s):
+ * Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+#include "cairoint.h"
+
+#if CAIRO_HAS_XCB_SHM_FUNCTIONS
+
+#include "cairo-xcb-private.h"
+#include "cairo-list-inline.h"
+#include "cairo-mempool-private.h"
+
+#include <xcb/shm.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <errno.h>
+
+#define CAIRO_MAX_SHM_MEMORY (16*1024*1024)
+
+/* a simple buddy allocator for memory pools
+ * XXX fragmentation? use Doug Lea's malloc?
+ */
+
+typedef struct _cairo_xcb_shm_mem_block cairo_xcb_shm_mem_block_t;
+
+typedef enum {
+ PENDING_WAIT,
+ PENDING_POLL
+} shm_wait_type_t;
+
+struct _cairo_xcb_shm_mem_pool {
+ int shmid;
+ uint32_t shmseg;
+ void *shm;
+
+ cairo_mempool_t mem;
+
+ cairo_list_t link;
+};
+
+static void
+_cairo_xcb_shm_mem_pool_destroy (cairo_xcb_shm_mem_pool_t *pool)
+{
+ cairo_list_del (&pool->link);
+
+ shmdt (pool->shm);
+ _cairo_mempool_fini (&pool->mem);
+
+ free (pool);
+}
+
+static void
+_cairo_xcb_shm_info_finalize (cairo_xcb_shm_info_t *shm_info)
+{
+ cairo_xcb_connection_t *connection = shm_info->connection;
+
+ assert (CAIRO_MUTEX_IS_LOCKED (connection->shm_mutex));
+
+ _cairo_mempool_free (&shm_info->pool->mem, shm_info->mem);
+ _cairo_freepool_free (&connection->shm_info_freelist, shm_info);
+
+ /* scan for old, unused pools - hold at least one in reserve */
+ if (! cairo_list_is_singular (&connection->shm_pools))
+ {
+ cairo_xcb_shm_mem_pool_t *pool, *next;
+ cairo_list_t head;
+
+ cairo_list_init (&head);
+ cairo_list_move (connection->shm_pools.next, &head);
+
+ cairo_list_foreach_entry_safe (pool, next, cairo_xcb_shm_mem_pool_t,
+ &connection->shm_pools, link)
+ {
+ if (pool->mem.free_bytes == pool->mem.max_bytes) {
+ _cairo_xcb_connection_shm_detach (connection, pool->shmseg);
+ _cairo_xcb_shm_mem_pool_destroy (pool);
+ }
+ }
+
+ cairo_list_move (head.next, &connection->shm_pools);
+ }
+}
+
+static void
+_cairo_xcb_shm_process_pending (cairo_xcb_connection_t *connection, shm_wait_type_t wait)
+{
+ cairo_xcb_shm_info_t *info, *next;
+ xcb_get_input_focus_reply_t *reply;
+
+ assert (CAIRO_MUTEX_IS_LOCKED (connection->shm_mutex));
+ cairo_list_foreach_entry_safe (info, next, cairo_xcb_shm_info_t,
+ &connection->shm_pending, pending)
+ {
+ switch (wait) {
+ case PENDING_WAIT:
+ reply = xcb_wait_for_reply (connection->xcb_connection,
+ info->sync.sequence, NULL);
+ break;
+ case PENDING_POLL:
+ if (! xcb_poll_for_reply (connection->xcb_connection,
+ info->sync.sequence,
+ (void **) &reply, NULL))
+ /* We cannot be sure the server finished with this image yet, so
+ * try again later. All other shm info are guaranteed to have a
+ * larger sequence number and thus don't have to be checked. */
+ return;
+ break;
+ default:
+ /* silence Clang static analyzer warning */
+ ASSERT_NOT_REACHED;
+ reply = NULL;
+ }
+
+ free (reply);
+ cairo_list_del (&info->pending);
+ _cairo_xcb_shm_info_finalize (info);
+ }
+}
+
+cairo_int_status_t
+_cairo_xcb_connection_allocate_shm_info (cairo_xcb_connection_t *connection,
+ size_t size,
+ cairo_bool_t might_reuse,
+ cairo_xcb_shm_info_t **shm_info_out)
+{
+ cairo_xcb_shm_info_t *shm_info;
+ cairo_xcb_shm_mem_pool_t *pool, *next;
+ size_t bytes, maxbits = 16, minbits = 8;
+ size_t shm_allocated = 0;
+ void *mem = NULL;
+ cairo_status_t status;
+
+ assert (connection->flags & CAIRO_XCB_HAS_SHM);
+
+ CAIRO_MUTEX_LOCK (connection->shm_mutex);
+ _cairo_xcb_shm_process_pending (connection, PENDING_POLL);
+
+ if (might_reuse) {
+ cairo_list_foreach_entry (shm_info, cairo_xcb_shm_info_t,
+ &connection->shm_pending, pending) {
+ if (shm_info->size >= size) {
+ cairo_list_del (&shm_info->pending);
+ CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
+
+ xcb_discard_reply (connection->xcb_connection, shm_info->sync.sequence);
+ shm_info->sync.sequence = XCB_NONE;
+
+ *shm_info_out = shm_info;
+ return CAIRO_STATUS_SUCCESS;
+ }
+ }
+ }
+
+ cairo_list_foreach_entry_safe (pool, next, cairo_xcb_shm_mem_pool_t,
+ &connection->shm_pools, link)
+ {
+ if (pool->mem.free_bytes > size) {
+ mem = _cairo_mempool_alloc (&pool->mem, size);
+ if (mem != NULL) {
+ /* keep the active pools towards the front */
+ cairo_list_move (&pool->link, &connection->shm_pools);
+ goto allocate_shm_info;
+ }
+ }
+ /* scan for old, unused pools */
+ if (pool->mem.free_bytes == pool->mem.max_bytes) {
+ _cairo_xcb_connection_shm_detach (connection,
+ pool->shmseg);
+ _cairo_xcb_shm_mem_pool_destroy (pool);
+ } else {
+ shm_allocated += pool->mem.max_bytes;
+ }
+ }
+
+ if (unlikely (shm_allocated >= CAIRO_MAX_SHM_MEMORY)) {
+ CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
+ return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+ }
+
+ pool = malloc (sizeof (cairo_xcb_shm_mem_pool_t));
+ if (unlikely (pool == NULL)) {
+ CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
+ return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+ }
+
+ bytes = 1 << maxbits;
+ while (bytes <= size)
+ bytes <<= 1, maxbits++;
+ bytes <<= 3;
+
+ do {
+ pool->shmid = shmget (IPC_PRIVATE, bytes, IPC_CREAT | 0600);
+ if (pool->shmid != -1)
+ break;
+
+ /* If the allocation failed because we asked for too much memory, we try
+ * again with a smaller request, as long as our allocation still fits. */
+ bytes >>= 1;
+ if (errno != EINVAL || bytes < size)
+ break;
+ } while (TRUE);
+ if (pool->shmid == -1) {
+ int err = errno;
+ if (! (err == EINVAL || err == ENOMEM))
+ connection->flags &= ~CAIRO_XCB_HAS_SHM;
+ free (pool);
+ CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
+ return CAIRO_INT_STATUS_UNSUPPORTED;
+ }
+
+ pool->shm = shmat (pool->shmid, NULL, 0);
+ if (unlikely (pool->shm == (char *) -1)) {
+ shmctl (pool->shmid, IPC_RMID, NULL);
+ free (pool);
+ CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
+ return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+ }
+
+ status = _cairo_mempool_init (&pool->mem, pool->shm, bytes,
+ minbits, maxbits - minbits + 1);
+ if (unlikely (status)) {
+ shmdt (pool->shm);
+ free (pool);
+ CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
+ return status;
+ }
+
+ pool->shmseg = _cairo_xcb_connection_shm_attach (connection, pool->shmid, FALSE);
+ shmctl (pool->shmid, IPC_RMID, NULL);
+
+ cairo_list_add (&pool->link, &connection->shm_pools);
+ mem = _cairo_mempool_alloc (&pool->mem, size);
+
+ allocate_shm_info:
+ shm_info = _cairo_freepool_alloc (&connection->shm_info_freelist);
+ if (unlikely (shm_info == NULL)) {
+ _cairo_mempool_free (&pool->mem, mem);
+ CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
+ return _cairo_error (CAIRO_STATUS_NO_MEMORY);
+ }
+
+ shm_info->connection = connection;
+ shm_info->pool = pool;
+ shm_info->shm = pool->shmseg;
+ shm_info->size = size;
+ shm_info->offset = (char *) mem - (char *) pool->shm;
+ shm_info->mem = mem;
+ shm_info->sync.sequence = XCB_NONE;
+
+ /* scan for old, unused pools */
+ cairo_list_foreach_entry_safe (pool, next, cairo_xcb_shm_mem_pool_t,
+ &connection->shm_pools, link)
+ {
+ if (pool->mem.free_bytes == pool->mem.max_bytes) {
+ _cairo_xcb_connection_shm_detach (connection,
+ pool->shmseg);
+ _cairo_xcb_shm_mem_pool_destroy (pool);
+ }
+ }
+ CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
+
+ *shm_info_out = shm_info;
+ return CAIRO_STATUS_SUCCESS;
+}
+
+void
+_cairo_xcb_shm_info_destroy (cairo_xcb_shm_info_t *shm_info)
+{
+ cairo_xcb_connection_t *connection = shm_info->connection;
+
+ /* We can only return shm_info->mem to the allocator when we can be sure
+ * that the X server no longer reads from it. Since the X server processes
+ * requests in order, we send a GetInputFocus here.
+ * _cairo_xcb_shm_process_pending () will later check if the reply for that
+ * request was received and then actually mark this memory area as free. */
+
+ CAIRO_MUTEX_LOCK (connection->shm_mutex);
+ assert (shm_info->sync.sequence == XCB_NONE);
+ shm_info->sync = xcb_get_input_focus (connection->xcb_connection);
+
+ cairo_list_init (&shm_info->pending);
+ cairo_list_add_tail (&shm_info->pending, &connection->shm_pending);
+ CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
+}
+
+void
+_cairo_xcb_connection_shm_mem_pools_flush (cairo_xcb_connection_t *connection)
+{
+ CAIRO_MUTEX_LOCK (connection->shm_mutex);
+ _cairo_xcb_shm_process_pending (connection, PENDING_WAIT);
+ CAIRO_MUTEX_UNLOCK (connection->shm_mutex);
+}
+
+void
+_cairo_xcb_connection_shm_mem_pools_fini (cairo_xcb_connection_t *connection)
+{
+ assert (cairo_list_is_empty (&connection->shm_pending));
+ while (! cairo_list_is_empty (&connection->shm_pools)) {
+ _cairo_xcb_shm_mem_pool_destroy (cairo_list_first_entry (&connection->shm_pools,
+ cairo_xcb_shm_mem_pool_t,
+ link));
+ }
+}
+
+#endif /* CAIRO_HAS_XCB_SHM_FUNCTIONS */