avutil/fifo: Deprecate old FIFO API

Users should switch to the superior AVFifo API.

Unfortunately AVFifoBuffer fields cannot be marked as deprecated because
it would trigger a warning wherever fifo.h is #included, due to
inlined av_fifo_peek2().

doc/APIchanges

@@ -14,6 +14,14 @@ libavutil:     2021-04-27
 
 API changes, most recent first:
 
+2022-02-07 - xxxxxxxxxx - lavu 57.21.100 - fifo.h
+  Deprecate AVFifoBuffer and the API around it, namely av_fifo_alloc(),
+  av_fifo_alloc_array(), av_fifo_free(), av_fifo_freep(), av_fifo_reset(),
+  av_fifo_size(), av_fifo_space(), av_fifo_generic_peek_at(),
+  av_fifo_generic_peek(), av_fifo_generic_read(), av_fifo_generic_write(),
+  av_fifo_realloc2(), av_fifo_grow(), av_fifo_drain() and av_fifo_peek2().
+  Users should switch to the AVFifo-API.
+
 2022-02-07 - xxxxxxxxxx - lavu 57.20.100 - fifo.h
   Add a new FIFO API, which allows setting a FIFO element size.
   This API operates on these elements rather than on bytes.

libavutil/fifo.c

@@ -287,6 +287,8 @@ void av_fifo_freep2(AVFifo **f)
 }
 
 
+#if FF_API_FIFO_OLD_API
+FF_DISABLE_DEPRECATION_WARNINGS
 #define OLD_FIFO_SIZE_MAX (size_t)FFMIN3(INT_MAX, UINT32_MAX, SIZE_MAX)
 
 AVFifoBuffer *av_fifo_alloc_array(size_t nmemb, size_t size)
@@ -499,3 +501,5 @@ void av_fifo_drain(AVFifoBuffer *f, int size)
         f->rptr -= f->end - f->buffer;
     f->rndx += size;
 }
+FF_ENABLE_DEPRECATION_WARNINGS
+#endif

libavutil/fifo.h

@@ -220,6 +220,7 @@ void av_fifo_reset2(AVFifo *f);
 void av_fifo_freep2(AVFifo **f);
 
 
+#if FF_API_FIFO_OLD_API
 typedef struct AVFifoBuffer {
     uint8_t *buffer;
     uint8_t *rptr, *wptr, *end;
@@ -230,7 +231,9 @@ typedef struct AVFifoBuffer {
  * Initialize an AVFifoBuffer.
  * @param size of FIFO
  * @return AVFifoBuffer or NULL in case of memory allocation failure
+ * @deprecated use av_fifo_alloc2()
  */
+attribute_deprecated
 AVFifoBuffer *av_fifo_alloc(unsigned int size);
 
 /**
@@ -238,25 +241,33 @@ AVFifoBuffer *av_fifo_alloc(unsigned int size);
  * @param nmemb number of elements
  * @param size  size of the single element
  * @return AVFifoBuffer or NULL in case of memory allocation failure
+ * @deprecated use av_fifo_alloc2()
  */
+attribute_deprecated
 AVFifoBuffer *av_fifo_alloc_array(size_t nmemb, size_t size);
 
 /**
  * Free an AVFifoBuffer.
  * @param f AVFifoBuffer to free
+ * @deprecated use the AVFifo API with av_fifo_freep2()
  */
+attribute_deprecated
 void av_fifo_free(AVFifoBuffer *f);
 
 /**
  * Free an AVFifoBuffer and reset pointer to NULL.
  * @param f AVFifoBuffer to free
+ * @deprecated use the AVFifo API with av_fifo_freep2()
  */
+attribute_deprecated
 void av_fifo_freep(AVFifoBuffer **f);
 
 /**
  * Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied.
  * @param f AVFifoBuffer to reset
+ * @deprecated use av_fifo_reset2() with the new AVFifo-API
  */
+attribute_deprecated
 void av_fifo_reset(AVFifoBuffer *f);
 
 /**
@@ -264,7 +275,9 @@ void av_fifo_reset(AVFifoBuffer *f);
  * amount of data you can read from it.
  * @param f AVFifoBuffer to read from
  * @return size
+ * @deprecated use av_fifo_can_read() with the new AVFifo-API
  */
+attribute_deprecated
 int av_fifo_size(const AVFifoBuffer *f);
 
 /**
@@ -272,7 +285,9 @@ int av_fifo_size(const AVFifoBuffer *f);
  * amount of data you can write into it.
  * @param f AVFifoBuffer to write into
  * @return size
+ * @deprecated use av_fifo_can_write() with the new AVFifo-API
  */
+attribute_deprecated
 int av_fifo_space(const AVFifoBuffer *f);
 
 /**
@@ -285,7 +300,11 @@ int av_fifo_space(const AVFifoBuffer *f);
  * @param dest data destination
  *
  * @return a non-negative number on success, a negative error code on failure
+ *
+ * @deprecated use the new AVFifo-API with av_fifo_peek() when func == NULL,
+ *             av_fifo_peek_to_cb() otherwise
  */
+attribute_deprecated
 int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_size, void (*func)(void*, void*, int));
 
 /**
@@ -297,7 +316,11 @@ int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_siz
  * @param dest data destination
  *
  * @return a non-negative number on success, a negative error code on failure
+ *
+ * @deprecated use the new AVFifo-API with av_fifo_peek() when func == NULL,
+ *             av_fifo_peek_to_cb() otherwise
  */
+attribute_deprecated
 int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
 
 /**
@@ -308,7 +331,11 @@ int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void (*func)
  * @param dest data destination
  *
  * @return a non-negative number on success, a negative error code on failure
+ *
+ * @deprecated use the new AVFifo-API with av_fifo_read() when func == NULL,
+ *             av_fifo_read_to_cb() otherwise
  */
+attribute_deprecated
 int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
 
 /**
@@ -323,7 +350,11 @@ int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)
  * indicate no more data available to write.
  * If func is NULL, src is interpreted as a simple byte array for source data.
  * @return the number of bytes written to the FIFO or a negative error code on failure
+ *
+ * @deprecated use the new AVFifo-API with av_fifo_write() when func == NULL,
+ *             av_fifo_write_from_cb() otherwise
  */
+attribute_deprecated
 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
 
 /**
@@ -333,7 +364,11 @@ int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void
  * @param f AVFifoBuffer to resize
  * @param size new AVFifoBuffer size in bytes
  * @return <0 for failure, >=0 otherwise
+ *
+ * @deprecated use the new AVFifo-API with av_fifo_grow2() to increase FIFO size,
+ *             decreasing FIFO size is not supported
  */
+attribute_deprecated
 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
 
 /**
@@ -344,14 +379,21 @@ int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
  * @param f AVFifoBuffer to resize
  * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size()
  * @return <0 for failure, >=0 otherwise
+ *
+ * @deprecated use the new AVFifo-API with av_fifo_grow2(); note that unlike
+ * this function it adds to the allocated size, rather than to the used size
  */
+attribute_deprecated
 int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space);
 
 /**
  * Read and discard the specified amount of data from an AVFifoBuffer.
  * @param f AVFifoBuffer to read from
  * @param size amount of data to read in bytes
+ *
+ * @deprecated use the new AVFifo-API with av_fifo_drain2()
  */
+attribute_deprecated
 void av_fifo_drain(AVFifoBuffer *f, int size);
 
 #if FF_API_FIFO_PEEK2
@@ -364,7 +406,7 @@ void av_fifo_drain(AVFifoBuffer *f, int size);
  *             than the used buffer size or the returned pointer will
  *             point outside to the buffer data.
  *             The used buffer size can be checked with av_fifo_size().
- * @deprecated use av_fifo_generic_peek_at()
+ * @deprecated use the new AVFifo-API with av_fifo_peek() or av_fifo_peek_to_cb()
  */
 attribute_deprecated
 static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs)
@@ -377,5 +419,6 @@ static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs)
     return ptr;
 }
 #endif
+#endif
 
 #endif /* AVUTIL_FIFO_H */

libavutil/version.h

@@ -79,7 +79,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR  57
-#define LIBAVUTIL_VERSION_MINOR  20
+#define LIBAVUTIL_VERSION_MINOR  21
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
@@ -110,6 +110,7 @@
 #define FF_API_COLORSPACE_NAME          (LIBAVUTIL_VERSION_MAJOR < 58)
 #define FF_API_AV_MALLOCZ_ARRAY         (LIBAVUTIL_VERSION_MAJOR < 58)
 #define FF_API_FIFO_PEEK2               (LIBAVUTIL_VERSION_MAJOR < 58)
+#define FF_API_FIFO_OLD_API             (LIBAVUTIL_VERSION_MAJOR < 58)
 
 /**
  * @}