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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 

 */

#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 

#include 

#include 

#include 

#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 */