X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmisc%2Fblock.c;h=0a408cc26d15766b7d531542638b7a36cd2f65b4;hb=7609918fc2e99dc7a0e163e13aec6e57bfd9b02b;hp=5bcdda3495c50525519cd425cf1a233c84d22263;hpb=3bd2238f49d7eaafdffd543add5e1385aa890a4b;p=vlc diff --git a/src/misc/block.c b/src/misc/block.c index 5bcdda3495..0a408cc26d 100644 --- a/src/misc/block.c +++ b/src/misc/block.c @@ -1,184 +1,540 @@ /***************************************************************************** * block.c: Data blocks management functions ***************************************************************************** - * Copyright (C) 2003-2004 the VideoLAN team - * $Id$ + * Copyright (C) 2003-2004 VLC authors and VideoLAN + * Copyright (C) 2007-2009 Rémi Denis-Courmont * * Authors: Laurent Aimar * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation; either version 2 of the License, or + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU Lesser General Public License as published by + * the Free Software Foundation; either version 2.1 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Lesser General Public License for more details. * - * You should have received a copy of the GNU General Public License - * along with this program; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA. + * You should have received a copy of the GNU Lesser General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA. *****************************************************************************/ /***************************************************************************** * Preamble *****************************************************************************/ -#include -#include "vlc_block.h" +#ifdef HAVE_CONFIG_H +# include "config.h" +#endif + +#include +#include +#include +#include +#include + +#include +#include +#include + +/** + * @section Block handling functions. + */ + +#ifndef NDEBUG +static void BlockNoRelease( block_t *b ) +{ + fprintf( stderr, "block %p has no release callback! This is a bug!\n", b ); + abort(); +} -/***************************************************************************** - * Block functions. - *****************************************************************************/ -/* private */ -struct block_sys_t +static void block_Check (block_t *block) { - uint8_t *p_allocated_buffer; - size_t i_allocated_buffer; -}; + while (block != NULL) + { + unsigned char *start = block->p_start; + unsigned char *end = block->p_start + block->i_size; + unsigned char *bufstart = block->p_buffer; + unsigned char *bufend = block->p_buffer + block->i_buffer; + + assert (block->pf_release != BlockNoRelease); + assert (start <= end); + assert (bufstart <= bufend); + assert (bufstart >= start); + assert (bufend <= end); + + block = block->p_next; + } +} + +static void block_Invalidate (block_t *block) +{ + block->p_next = NULL; + block_Check (block); + block->pf_release = BlockNoRelease; +} +#else +# define block_Check(b) ((void)(b)) +# define block_Invalidate(b) ((void)(b)) +#endif + +void block_Init( block_t *restrict b, void *buf, size_t size ) +{ + /* Fill all fields to their default */ + b->p_next = NULL; + b->p_buffer = buf; + b->i_buffer = size; + b->p_start = buf; + b->i_size = size; + b->i_flags = 0; + b->i_nb_samples = 0; + b->i_pts = + b->i_dts = VLC_TS_INVALID; + b->i_length = 0; +#ifndef NDEBUG + b->pf_release = BlockNoRelease; +#endif +} + +static void block_generic_Release (block_t *block) +{ + /* That is always true for blocks allocated with block_Alloc(). */ + assert (block->p_start == (unsigned char *)(block + 1)); + block_Invalidate (block); + free (block); +} + +static void BlockMetaCopy( block_t *restrict out, const block_t *in ) +{ + out->p_next = in->p_next; + out->i_nb_samples = in->i_nb_samples; + out->i_dts = in->i_dts; + out->i_pts = in->i_pts; + out->i_flags = in->i_flags; + out->i_length = in->i_length; +} + +/** Initial memory alignment of data block. + * @note This must be a multiple of sizeof(void*) and a power of two. + * libavcodec AVX optimizations require at least 32-bytes. */ +#define BLOCK_ALIGN 32 + +/** Initial reserved header and footer size. */ +#define BLOCK_PADDING 32 -#define BLOCK_PADDING_SIZE 32 -static void BlockRelease( block_t * ); +/* Maximum size of reserved footer before shrinking with realloc(). */ +#define BLOCK_WASTE_SIZE 2048 -block_t *__block_New( vlc_object_t *p_obj, size_t i_size ) +block_t *block_Alloc (size_t size) { - /* We do only one malloc - * TODO bench if doing 2 malloc but keeping a pool of buffer is better - * 16 -> align on 16 - * 2 * BLOCK_PADDING_SIZE -> pre + post padding - */ - block_sys_t *p_sys; - const size_t i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + 16; - block_t *p_block = - malloc( sizeof( block_t ) + sizeof( block_sys_t ) + i_alloc ); - - if( p_block == NULL ) + /* 2 * BLOCK_PADDING: pre + post padding */ + const size_t alloc = sizeof (block_t) + BLOCK_ALIGN + (2 * BLOCK_PADDING) + + size; + if (unlikely(alloc <= size)) return NULL; - /* Fill opaque data */ - p_sys = (block_sys_t*)( (uint8_t*)p_block + sizeof( block_t ) ); - p_sys->i_allocated_buffer = i_alloc; - p_sys->p_allocated_buffer = (uint8_t*)p_block + sizeof( block_t ) + - sizeof( block_sys_t ); - - /* Fill all fields */ - p_block->p_next = NULL; - p_block->p_prev = NULL; - p_block->i_flags = 0; - p_block->i_pts = 0; - p_block->i_dts = 0; - p_block->i_length = 0; - p_block->i_rate = 0; - p_block->i_buffer = i_size; - p_block->p_buffer = - &p_sys->p_allocated_buffer[BLOCK_PADDING_SIZE + - 16 - ((uintptr_t)p_sys->p_allocated_buffer % 16 )]; - p_block->pf_release = BlockRelease; - - /* Is ok, as no comunication between p_vlc */ - p_block->p_manager = VLC_OBJECT( p_obj->p_libvlc ); - p_block->p_sys = p_sys; + block_t *b = malloc (alloc); + if (unlikely(b == NULL)) + return NULL; - return p_block; + block_Init (b, b + 1, alloc - sizeof (*b)); + static_assert ((BLOCK_PADDING % BLOCK_ALIGN) == 0, + "BLOCK_PADDING must be a multiple of BLOCK_ALIGN"); + b->p_buffer += BLOCK_PADDING + BLOCK_ALIGN - 1; + b->p_buffer = (void *)(((uintptr_t)b->p_buffer) & ~(BLOCK_ALIGN - 1)); + b->i_buffer = size; + b->pf_release = block_generic_Release; + return b; } block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body ) { - ssize_t i_buffer_size; + size_t requested = i_prebody + i_body; - if( p_block->pf_release != BlockRelease ) + block_Check( p_block ); + + /* Corner case: empty block requested */ + if( i_prebody <= 0 && i_body <= (size_t)(-i_prebody) ) { - /* Special case when pf_release if overloaded - * TODO if used one day, them implement it in a smarter way */ - block_t *p_dup = block_Duplicate( p_block ); block_Release( p_block ); - if( !p_dup ) - return NULL; - - p_block = p_dup; + return NULL; } - i_buffer_size = i_prebody + i_body; + assert( p_block->p_start <= p_block->p_buffer ); + assert( p_block->p_start + p_block->i_size + >= p_block->p_buffer + p_block->i_buffer ); - if( i_buffer_size <= 0 ) + /* Corner case: the current payload is discarded completely */ + if( i_prebody <= 0 && p_block->i_buffer <= (size_t)-i_prebody ) + p_block->i_buffer = 0; /* discard current payload */ + if( p_block->i_buffer == 0 ) { + if( requested <= p_block->i_size ) + { /* Enough room: recycle buffer */ + size_t extra = p_block->i_size - requested; + + p_block->p_buffer = p_block->p_start + (extra / 2); + p_block->i_buffer = requested; + return p_block; + } + /* Not enough room: allocate a new buffer */ + block_t *p_rea = block_Alloc( requested ); + if( p_rea ) + BlockMetaCopy( p_rea, p_block ); block_Release( p_block ); - return NULL; + return p_rea; } - if( p_block->p_buffer - i_prebody > p_block->p_sys->p_allocated_buffer && - p_block->p_buffer - i_prebody < p_block->p_sys->p_allocated_buffer + - p_block->p_sys->i_allocated_buffer ) + /* First, shrink payload */ + + /* Pull payload start */ + if( i_prebody < 0 ) { + assert( p_block->i_buffer >= (size_t)-i_prebody ); p_block->p_buffer -= i_prebody; p_block->i_buffer += i_prebody; + i_body += i_prebody; i_prebody = 0; } - if( p_block->p_buffer + i_body < p_block->p_sys->p_allocated_buffer + - p_block->p_sys->i_allocated_buffer ) + + /* Trim payload end */ + if( p_block->i_buffer > i_body ) + p_block->i_buffer = i_body; + + uint8_t *p_start = p_block->p_start; + uint8_t *p_end = p_start + p_block->i_size; + + /* Second, reallocate the buffer if we lack space. This is done now to + * minimize the payload size for memory copy. */ + assert( i_prebody >= 0 ); + if( (size_t)(p_block->p_buffer - p_start) < (size_t)i_prebody + || (size_t)(p_end - p_block->p_buffer) < i_body ) { - p_block->i_buffer = i_buffer_size; - i_body = 0; + block_t *p_rea = block_Alloc( requested ); + if( p_rea ) + { + BlockMetaCopy( p_rea, p_block ); + p_rea->p_buffer += i_prebody; + p_rea->i_buffer -= i_prebody; + memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer ); + } + block_Release( p_block ); + if( p_rea == NULL ) + return NULL; + p_block = p_rea; } - - if( i_body > 0 || i_prebody > 0 ) + else + /* We have a very large reserved footer now? Release some of it. + * XXX it might not preserve the alignment of p_buffer */ + if( p_end - (p_block->p_buffer + i_body) > BLOCK_WASTE_SIZE ) { - block_t *p_rea = block_New( p_block->p_manager, i_buffer_size ); - + block_t *p_rea = block_Alloc( requested ); if( p_rea ) { - p_rea->i_dts = p_block->i_dts; - p_rea->i_pts = p_block->i_pts; - p_rea->i_flags = p_block->i_flags; - p_rea->i_length = p_block->i_length; - p_rea->i_rate = p_block->i_rate; - p_rea->i_samples = p_block->i_samples; - - memcpy( p_rea->p_buffer + i_prebody, p_block->p_buffer, - __MIN( p_block->i_buffer, p_rea->i_buffer - i_prebody ) ); + BlockMetaCopy( p_rea, p_block ); + p_rea->p_buffer += i_prebody; + p_rea->i_buffer -= i_prebody; + memcpy( p_rea->p_buffer, p_block->p_buffer, p_block->i_buffer ); + block_Release( p_block ); + p_block = p_rea; } + } - block_Release( p_block ); + /* NOTE: p_start and p_end are corrupted from this point */ - return p_rea; + /* Third, expand payload */ + + /* Push payload start */ + if( i_prebody > 0 ) + { + p_block->p_buffer -= i_prebody; + p_block->i_buffer += i_prebody; + i_body += i_prebody; + i_prebody = 0; } + /* Expand payload to requested size */ + p_block->i_buffer = i_body; + return p_block; } -static void BlockRelease( block_t *p_block ) + +static void block_heap_Release (block_t *block) { - free( p_block ); + block_Invalidate (block); + free (block->p_start); + free (block); } +/** + * Creates a block from a heap allocation. + * This is provided by LibVLC so that manually heap-allocated blocks can safely + * be deallocated even after the origin plugin has been unloaded from memory. + * + * When block_Release() is called, VLC will free() the specified pointer. + * + * @param ptr base address of the heap allocation (will be free()'d) + * @param length bytes length of the heap allocation + * @return NULL in case of error (ptr free()'d in that case), or a valid + * block_t pointer. + */ +block_t *block_heap_Alloc (void *addr, size_t length) +{ + block_t *block = malloc (sizeof (*block)); + if (block == NULL) + { + free (addr); + return NULL; + } -/***************************************************************************** - * block_fifo_t management - *****************************************************************************/ + block_Init (block, addr, length); + block->pf_release = block_heap_Release; + return block; +} + +#ifdef HAVE_MMAP +# include + +static void block_mmap_Release (block_t *block) +{ + block_Invalidate (block); + munmap (block->p_start, block->i_size); + free (block); +} + +/** + * Creates a block from a virtual address memory mapping (mmap). + * This is provided by LibVLC so that mmap blocks can safely be deallocated + * even after the allocating plugin has been unloaded from memory. + * + * @param addr base address of the mapping (as returned by mmap) + * @param length length (bytes) of the mapping (as passed to mmap) + * @return NULL if addr is MAP_FAILED, or an error occurred (in the later + * case, munmap(addr, length) is invoked before returning). + */ +block_t *block_mmap_Alloc (void *addr, size_t length) +{ + if (addr == MAP_FAILED) + return NULL; + + block_t *block = malloc (sizeof (*block)); + if (block == NULL) + { + munmap (addr, length); + return NULL; + } + + block_Init (block, addr, length); + block->pf_release = block_mmap_Release; + return block; +} +#else +block_t *block_mmap_Alloc (void *addr, size_t length) +{ + (void)addr; (void)length; return NULL; +} +#endif + +#ifdef HAVE_SYS_SHM_H +# include + +typedef struct block_shm_t +{ + block_t self; + void *base_addr; +} block_shm_t; + +static void block_shm_Release (block_t *block) +{ + block_shm_t *p_sys = (block_shm_t *)block; + + shmdt (p_sys->base_addr); + free (p_sys); +} + +/** + * Creates a block from a System V shared memory segment (shmget()). + * This is provided by LibVLC so that segments can safely be deallocated + * even after the allocating plugin has been unloaded from memory. + * + * @param addr base address of the segment (as returned by shmat()) + * @param length length (bytes) of the segment (as passed to shmget()) + * @return NULL if an error occurred (in that case, shmdt(addr) is invoked + * before returning NULL). + */ +block_t *block_shm_Alloc (void *addr, size_t length) +{ + block_shm_t *block = malloc (sizeof (*block)); + if (unlikely(block == NULL)) + { + shmdt (addr); + return NULL; + } + + block_Init (&block->self, (uint8_t *)addr, length); + block->self.pf_release = block_shm_Release; + block->base_addr = addr; + return &block->self; +} +#else +block_t *block_shm_Alloc (void *addr, size_t length) +{ + (void) addr; (void) length; + abort (); +} +#endif + + +#ifdef _WIN32 +# include + +static +ssize_t pread (int fd, void *buf, size_t count, off_t offset) +{ + HANDLE handle = (HANDLE)(intptr_t)_get_osfhandle (fd); + if (handle == INVALID_HANDLE_VALUE) + return -1; + + OVERLAPPED olap; olap.Offset = offset; olap.OffsetHigh = (offset >> 32); + DWORD written; + /* This braindead API will override the file pointer even if we specify + * an explicit read offset... So do not expect this to mix well with + * regular read() calls. */ + if (ReadFile (handle, buf, count, &written, &olap)) + return written; + return -1; +} +#endif + +/** + * Loads a file into a block of memory through a file descriptor. + * If possible a private file mapping is created. Otherwise, the file is read + * normally. This function is a cancellation point. + * + * @note On 32-bits platforms, + * this function will not work for very large files, + * due to memory space constraints. + * + * @param fd file descriptor to load from + * @return a new block with the file content at p_buffer, and file length at + * i_buffer (release it with block_Release()), or NULL upon error (see errno). + */ +block_t *block_File (int fd) +{ + size_t length; + struct stat st; + + /* First, get the file size */ + if (fstat (fd, &st)) + return NULL; + + /* st_size is meaningful for regular files, shared memory and typed memory. + * It's also meaning for symlinks, but that's not possible with fstat(). + * In other cases, it's undefined, and we should really not go further. */ +#ifndef S_TYPEISSHM +# define S_TYPEISSHM( buf ) (0) +#endif + if (S_ISDIR (st.st_mode)) + { + errno = EISDIR; + return NULL; + } + if (!S_ISREG (st.st_mode) && !S_TYPEISSHM (&st)) + { + errno = ESPIPE; + return NULL; + } + + /* Prevent an integer overflow in mmap() and malloc() */ + if ((uintmax_t)st.st_size >= SIZE_MAX) + { + errno = ENOMEM; + return NULL; + } + length = (size_t)st.st_size; + +#ifdef HAVE_MMAP + if (length > 0) + { + void *addr; + + addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); + if (addr != MAP_FAILED) + return block_mmap_Alloc (addr, length); + } +#endif + + /* If mmap() is not implemented by the OS _or_ the filesystem... */ + block_t *block = block_Alloc (length); + if (block == NULL) + return NULL; + block_cleanup_push (block); + + for (size_t i = 0; i < length;) + { + ssize_t len = pread (fd, block->p_buffer + i, length - i, i); + if (len == -1) + { + block_Release (block); + block = NULL; + break; + } + i += len; + } + vlc_cleanup_pop (); + return block; +} + +/** + * Loads a file into a block of memory from the file path. + * See also block_File(). + */ +block_t *block_FilePath (const char *path) +{ + int fd = vlc_open (path, O_RDONLY); + if (fd == -1) + return NULL; + + block_t *block = block_File (fd); + close (fd); + return block; +} + +/** + * @section Thread-safe block queue functions + */ + +/** + * Internal state for block queues + */ struct block_fifo_t { vlc_mutex_t lock; /* fifo data lock */ - vlc_cond_t wait; /* fifo data conditional variable */ + vlc_cond_t wait; /**< Wait for data */ + vlc_cond_t wait_room; /**< Wait for queue depth to shrink */ block_t *p_first; block_t **pp_last; size_t i_depth; size_t i_size; - vlc_bool_t b_force_wake; + bool b_force_wake; }; -block_fifo_t *__block_FifoNew( vlc_object_t *p_obj ) +block_fifo_t *block_FifoNew( void ) { - block_fifo_t *p_fifo; + block_fifo_t *p_fifo = malloc( sizeof( block_fifo_t ) ); + if( !p_fifo ) + return NULL; - p_fifo = malloc( sizeof( block_fifo_t ) ); - if( !p_fifo ) return NULL; - vlc_mutex_init( p_obj, &p_fifo->lock ); - vlc_cond_init( p_obj, &p_fifo->wait ); + vlc_mutex_init( &p_fifo->lock ); + vlc_cond_init( &p_fifo->wait ); + vlc_cond_init( &p_fifo->wait_room ); p_fifo->p_first = NULL; p_fifo->pp_last = &p_fifo->p_first; p_fifo->i_depth = p_fifo->i_size = 0; - p_fifo->b_force_wake = VLC_FALSE; + p_fifo->b_force_wake = false; return p_fifo; } @@ -186,6 +542,7 @@ block_fifo_t *__block_FifoNew( vlc_object_t *p_obj ) void block_FifoRelease( block_fifo_t *p_fifo ) { block_FifoEmpty( p_fifo ); + vlc_cond_destroy( &p_fifo->wait_room ); vlc_cond_destroy( &p_fifo->wait ); vlc_mutex_destroy( &p_fifo->lock ); free( p_fifo ); @@ -193,43 +550,87 @@ void block_FifoRelease( block_fifo_t *p_fifo ) void block_FifoEmpty( block_fifo_t *p_fifo ) { - block_t *b; + block_t *block; vlc_mutex_lock( &p_fifo->lock ); - for( b = p_fifo->p_first; b != NULL; ) + block = p_fifo->p_first; + if (block != NULL) { - block_t *p_next; - - p_next = b->p_next; - block_Release( b ); - b = p_next; + p_fifo->i_depth = p_fifo->i_size = 0; + p_fifo->p_first = NULL; + p_fifo->pp_last = &p_fifo->p_first; } - - p_fifo->i_depth = p_fifo->i_size = 0; - p_fifo->p_first = NULL; - p_fifo->pp_last = &p_fifo->p_first; + vlc_cond_broadcast( &p_fifo->wait_room ); vlc_mutex_unlock( &p_fifo->lock ); + + while (block != NULL) + { + block_t *buf; + + buf = block->p_next; + block_Release (block); + block = buf; + } } -size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block ) +/** + * Wait until the FIFO gets below a certain size (if needed). + * + * Note that if more than one thread writes to the FIFO, you cannot assume that + * the FIFO is actually below the requested size upon return (since another + * thread could have refilled it already). This is typically not an issue, as + * this function is meant for (relaxed) congestion control. + * + * This function may be a cancellation point and it is cancel-safe. + * + * @param fifo queue to wait on + * @param max_depth wait until the queue has no more than this many blocks + * (use SIZE_MAX to ignore this constraint) + * @param max_size wait until the queue has no more than this many bytes + * (use SIZE_MAX to ignore this constraint) + * @return nothing. + */ +void block_FifoPace (block_fifo_t *fifo, size_t max_depth, size_t max_size) { - size_t i_size = 0; - vlc_mutex_lock( &p_fifo->lock ); + vlc_testcancel (); - do + vlc_mutex_lock (&fifo->lock); + while ((fifo->i_depth > max_depth) || (fifo->i_size > max_size)) { - i_size += p_block->i_buffer; - - *p_fifo->pp_last = p_block; - p_fifo->pp_last = &p_block->p_next; - p_fifo->i_depth++; - p_fifo->i_size += p_block->i_buffer; + mutex_cleanup_push (&fifo->lock); + vlc_cond_wait (&fifo->wait_room, &fifo->lock); + vlc_cleanup_pop (); + } + vlc_mutex_unlock (&fifo->lock); +} - p_block = p_block->p_next; +/** + * Immediately queue one block at the end of a FIFO. + * @param fifo queue + * @param block head of a block list to queue (may be NULL) + * @return total number of bytes appended to the queue + */ +size_t block_FifoPut( block_fifo_t *p_fifo, block_t *p_block ) +{ + size_t i_size = 0, i_depth = 0; + block_t *p_last; - } while( p_block ); + if (p_block == NULL) + return 0; + for (p_last = p_block; ; p_last = p_last->p_next) + { + i_size += p_last->i_buffer; + i_depth++; + if (!p_last->p_next) + break; + } - /* warn there is data in this fifo */ + vlc_mutex_lock (&p_fifo->lock); + *p_fifo->pp_last = p_block; + p_fifo->pp_last = &p_last->p_next; + p_fifo->i_depth += i_depth; + p_fifo->i_size += i_size; + /* We queued at least one block: wake up one read-waiting thread */ vlc_cond_signal( &p_fifo->wait ); vlc_mutex_unlock( &p_fifo->lock ); @@ -240,27 +641,35 @@ void block_FifoWake( block_fifo_t *p_fifo ) { vlc_mutex_lock( &p_fifo->lock ); if( p_fifo->p_first == NULL ) - p_fifo->b_force_wake = VLC_TRUE; - vlc_cond_signal( &p_fifo->wait ); + p_fifo->b_force_wake = true; + vlc_cond_broadcast( &p_fifo->wait ); vlc_mutex_unlock( &p_fifo->lock ); } +/** + * Dequeue the first block from the FIFO. If necessary, wait until there is + * one block in the queue. This function is (always) cancellation point. + * + * @return a valid block, or NULL if block_FifoWake() was called. + */ block_t *block_FifoGet( block_fifo_t *p_fifo ) { block_t *b; + vlc_testcancel( ); + vlc_mutex_lock( &p_fifo->lock ); + mutex_cleanup_push( &p_fifo->lock ); /* Remember vlc_cond_wait() may cause spurious wakeups * (on both Win32 and POSIX) */ while( ( p_fifo->p_first == NULL ) && !p_fifo->b_force_wake ) - { vlc_cond_wait( &p_fifo->wait, &p_fifo->lock ); - } + vlc_cleanup_pop(); b = p_fifo->p_first; - p_fifo->b_force_wake = VLC_FALSE; + p_fifo->b_force_wake = false; if( b == NULL ) { /* Forced wakeup */ @@ -277,36 +686,61 @@ block_t *block_FifoGet( block_fifo_t *p_fifo ) p_fifo->pp_last = &p_fifo->p_first; } + /* We don't know how many threads can queue new packets now. */ + vlc_cond_broadcast( &p_fifo->wait_room ); vlc_mutex_unlock( &p_fifo->lock ); b->p_next = NULL; return b; } +/** + * Peeks the first block in the FIFO. + * If necessary, wait until there is one block. + * This function is (always) a cancellation point. + * + * @warning This function leaves the block in the FIFO. + * You need to protect against concurrent threads who could dequeue the block. + * Preferrably, there should be only one thread reading from the FIFO. + * + * @return a valid block. + */ block_t *block_FifoShow( block_fifo_t *p_fifo ) { block_t *b; + vlc_testcancel( ); + vlc_mutex_lock( &p_fifo->lock ); + mutex_cleanup_push( &p_fifo->lock ); - if( p_fifo->p_first == NULL ) - { + while( p_fifo->p_first == NULL ) vlc_cond_wait( &p_fifo->wait, &p_fifo->lock ); - } b = p_fifo->p_first; - vlc_mutex_unlock( &p_fifo->lock ); - - return( b ); + vlc_cleanup_run (); + return b; } -size_t block_FifoSize( const block_fifo_t *p_fifo ) +/* FIXME: not (really) thread-safe */ +size_t block_FifoSize (block_fifo_t *fifo) { - return p_fifo->i_size; + size_t size; + + vlc_mutex_lock (&fifo->lock); + size = fifo->i_size; + vlc_mutex_unlock (&fifo->lock); + return size; } -size_t block_FifoCount( const block_fifo_t *p_fifo ) +/* FIXME: not (really) thread-safe */ +size_t block_FifoCount (block_fifo_t *fifo) { - return p_fifo->i_depth; + size_t depth; + + vlc_mutex_lock (&fifo->lock); + depth = fifo->i_depth; + vlc_mutex_unlock (&fifo->lock); + return depth; }