* block.c: Data blocks management functions
*****************************************************************************
* Copyright (C) 2003-2004 the VideoLAN team
- * $Id$
+ * Copyright (C) 2007-2009 Rémi Denis-Courmont
*
* Authors: Laurent Aimar <fenrir@videolan.org>
*
/*****************************************************************************
* Preamble
*****************************************************************************/
-#include <stdlib.h>
-
-#include <vlc/vlc.h>
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <vlc_common.h>
+#include <sys/stat.h>
+#include <assert.h>
+#include <errno.h>
#include "vlc_block.h"
-/*****************************************************************************
- * Block functions.
- *****************************************************************************/
-/* private */
+/**
+ * @section Block handling functions.
+ */
+
+/**
+ * Internal state for heap block.
+ */
struct block_sys_t
{
- uint8_t *p_allocated_buffer;
- int i_allocated_buffer;
+ block_t self;
+ size_t i_allocated_buffer;
+ uint8_t p_allocated_buffer[];
};
-#define BLOCK_PADDING_SIZE 32
-static void BlockRelease( block_t * );
+#ifndef NDEBUG
+static void BlockNoRelease( block_t *b )
+{
+ fprintf( stderr, "block %p has no release callback! This is a bug!\n", b );
+ abort();
+}
+#endif
+
+void block_Init( block_t *restrict b, void *buf, size_t size )
+{
+ /* Fill all fields to their default */
+ b->p_next = NULL;
+ b->i_flags = 0;
+ b->i_pts =
+ b->i_dts = VLC_TS_INVALID;
+ b->i_length = 0;
+ b->i_rate = 0;
+ b->i_nb_samples = 0;
+ b->p_buffer = buf;
+ b->i_buffer = size;
+#ifndef NDEBUG
+ b->pf_release = BlockNoRelease;
+#endif
+}
-block_t *__block_New( vlc_object_t *p_obj, int i_size )
+static void BlockRelease( block_t *p_block )
+{
+ free( p_block );
+}
+
+static void BlockMetaCopy( block_t *restrict out, const block_t *in )
+{
+ out->p_next = in->p_next;
+ out->i_dts = in->i_dts;
+ out->i_pts = in->i_pts;
+ out->i_flags = in->i_flags;
+ out->i_length = in->i_length;
+ out->i_rate = in->i_rate;
+ out->i_nb_samples = in->i_nb_samples;
+}
+
+/* Memory alignment (must be a multiple of sizeof(void*) and a power of two) */
+#define BLOCK_ALIGN 16
+/* Initial reserved header and footer size (must be multiple of alignment) */
+#define BLOCK_PADDING 32
+/* Maximum size of reserved footer before we release with realloc() */
+#define BLOCK_WASTE_SIZE 2048
+
+block_t *block_Alloc( size_t i_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
+ * TODO: bench if doing 2 malloc but keeping a pool of buffer is better
+ * 2 * BLOCK_PADDING -> pre + post padding
*/
block_sys_t *p_sys;
- const int i_alloc = i_size + 2 * BLOCK_PADDING_SIZE + 16;
- block_t *p_block =
- malloc( sizeof( block_t ) + sizeof( block_sys_t ) + i_alloc );
+ uint8_t *buf;
+
+#define ALIGN(x) (((x) + BLOCK_ALIGN - 1) & ~(BLOCK_ALIGN - 1))
+#if 0 /*def HAVE_POSIX_MEMALIGN */
+ /* posix_memalign(,16,) is much slower than malloc() on glibc.
+ * -- Courmisch, September 2009, glibc 2.5 & 2.9 */
+ const size_t i_alloc = ALIGN(sizeof(*p_sys)) + (2 * BLOCK_PADDING)
+ + ALIGN(i_size);
+ void *ptr;
+
+ if( posix_memalign( &ptr, BLOCK_ALIGN, i_alloc ) )
+ return NULL;
+
+ p_sys = ptr;
+ buf = p_sys->p_allocated_buffer + (-sizeof(*p_sys) & (BLOCK_ALIGN - 1));
- if( p_block == NULL )
+#else
+ const size_t i_alloc = sizeof(*p_sys) + BLOCK_ALIGN + (2 * BLOCK_PADDING)
+ + ALIGN(i_size);
+ p_sys = malloc( i_alloc );
+ if( p_sys == NULL )
return NULL;
+ buf = (void *)ALIGN((uintptr_t)p_sys->p_allocated_buffer);
+
+#endif
+ buf += BLOCK_PADDING;
+
+ block_Init( &p_sys->self, buf, i_size );
+ p_sys->self.pf_release = BlockRelease;
/* 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;
+ p_sys->i_allocated_buffer = i_alloc - sizeof(*p_sys);
- return p_block;
+ return &p_sys->self;
}
-block_t *block_Realloc( block_t *p_block, int i_prebody, int i_body )
+block_t *block_Realloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
{
- int i_buffer_size;
+ block_sys_t *p_sys = (block_sys_t *)p_block;
+ size_t requested = i_prebody + i_body;
+
+ /* Corner case: empty block requested */
+ if( i_prebody <= 0 && i_body <= (size_t)(-i_prebody) )
+ {
+ block_Release( p_block );
+ return NULL;
+ }
if( p_block->pf_release != BlockRelease )
{
/* Special case when pf_release if overloaded
- * TODO if used one day, them implement it in a smarter way */
+ * TODO if used one day, then 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;
+ p_sys = (block_sys_t *)p_block;
}
- i_buffer_size = i_prebody + i_body;
+ uint8_t *p_start = p_sys->p_allocated_buffer;
+ uint8_t *p_end = p_sys->p_allocated_buffer + p_sys->i_allocated_buffer;
+
+ assert( p_block->p_buffer + p_block->i_buffer <= p_end );
+ assert( p_block->p_buffer >= p_start );
- if( i_body < 0 || 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 )
{
+ size_t available = p_end - p_start;
+
+ if( requested <= available )
+ { /* Enough room: recycle buffer */
+ size_t extra = available - requested;
+
+ p_block->p_buffer = 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;
+
+ /* 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 )
+
+typedef struct
{
- free( p_block );
+ block_t self;
+ void *mem;
+} block_heap_t;
+
+static void block_heap_Release (block_t *self)
+{
+ block_heap_t *block = (block_heap_t *)self;
+
+ free (block->mem);
+ 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 addr base address of the useful buffer data
+ * @param length bytes length of the useful buffer data
+ * @return NULL in case of error (ptr free()'d in that case), or a valid
+ * block_t pointer.
+ */
+block_t *block_heap_Alloc (void *ptr, void *addr, size_t length)
+{
+ block_heap_t *block = malloc (sizeof (*block));
+ if (block == NULL)
+ {
+ free (addr);
+ return NULL;
+ }
-/*****************************************************************************
- * block_fifo_t management
- *****************************************************************************/
-block_fifo_t *__block_FifoNew( vlc_object_t *p_obj )
+ block_Init (&block->self, (uint8_t *)addr, length);
+ block->self.pf_release = block_heap_Release;
+ block->mem = ptr;
+ return &block->self;
+}
+
+#ifdef HAVE_MMAP
+# include <sys/mman.h>
+
+typedef struct block_mmap_t
{
- block_fifo_t *p_fifo;
+ block_t self;
+ void *base_addr;
+ size_t length;
+} block_mmap_t;
- p_fifo = malloc( sizeof( block_fifo_t ) );
- vlc_mutex_init( p_obj, &p_fifo->lock );
- vlc_cond_init( p_obj, &p_fifo->wait );
- p_fifo->i_depth = p_fifo->i_size = 0;
+static void block_mmap_Release (block_t *block)
+{
+ block_mmap_t *p_sys = (block_mmap_t *)block;
+
+ munmap (p_sys->base_addr, p_sys->length);
+ free (p_sys);
+}
+
+/**
+ * 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_mmap_t *block = malloc (sizeof (*block));
+ if (block == NULL)
+ {
+ munmap (addr, length);
+ return NULL;
+ }
+
+ block_Init (&block->self, (uint8_t *)addr, length);
+ block->self.pf_release = block_mmap_Release;
+ block->base_addr = addr;
+ block->length = length;
+ return &block->self;
+}
+#else
+block_t *block_mmap_Alloc (void *addr, size_t length)
+{
+ (void)addr; (void)length; return NULL;
+}
+#endif
+
+
+#ifdef WIN32
+# include <io.h>
+#ifdef UNDER_CE
+#define _get_osfhandle(a) ((long) (a))
+#endif
+
+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. If possible a private file mapping is
+ * created. Otherwise, the file is read normally. On 32-bits platforms, this
+ * function will not work for very large files, due to memory space
+ * constraints. Cancellation point.
+ *
+ * @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 (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;
+}
+
+/**
+ * @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; /**< 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;
+ bool b_force_wake;
+};
+
+block_fifo_t *block_FifoNew( void )
+{
+ block_fifo_t *p_fifo = malloc( sizeof( block_fifo_t ) );
+ if( !p_fifo )
+ return NULL;
+
+ 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 = false;
return p_fifo;
}
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 );
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;
+ }
}
-int 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)
{
- int 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 );
return i_size;
}
+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 = 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 );
- /* We do a while here because there is a race condition in the
- * win32 implementation of vlc_cond_wait() (We can't be sure the fifo
- * hasn't been emptied again since we were signaled). */
- while( p_fifo->p_first == NULL )
- {
+ /* 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 = false;
+ if( b == NULL )
+ {
+ /* Forced wakeup */
+ vlc_mutex_unlock( &p_fifo->lock );
+ return NULL;
+ }
+
p_fifo->p_first = b->p_next;
p_fifo->i_depth--;
p_fifo->i_size -= b->i_buffer;
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;
+}
+/* FIXME: not thread-safe */
+size_t block_FifoSize( const block_fifo_t *p_fifo )
+{
+ return p_fifo->i_size;
}
+/* FIXME: not thread-safe */
+size_t block_FifoCount( const block_fifo_t *p_fifo )
+{
+ return p_fifo->i_depth;
+}
projects / vlc / blobdiff