From 36117968ad66d7e4a461eb2d22e2a5f5c494120e Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Fri, 7 Jan 2022 11:41:42 +0100
Subject: [PATCH] lavf/async: switch to new FIFO API

---
 libavformat/async.c | 68 ++++++++++++++++++++++-----------------------
 1 file changed, 33 insertions(+), 35 deletions(-)

diff --git a/libavformat/async.c b/libavformat/async.c
index 5a81507ef1..547417aa1e 100644
--- a/libavformat/async.c
+++ b/libavformat/async.c
@@ -47,7 +47,7 @@
 
 typedef struct RingBuffer
 {
-    AVFifoBuffer *fifo;
+    AVFifo       *fifo;
     int           read_back_capacity;
 
     int           read_pos;
@@ -83,7 +83,7 @@ typedef struct Context {
 static int ring_init(RingBuffer *ring, unsigned int capacity, int read_back_capacity)
 {
     memset(ring, 0, sizeof(RingBuffer));
-    ring->fifo = av_fifo_alloc(capacity + read_back_capacity);
+    ring->fifo = av_fifo_alloc2(capacity + read_back_capacity, 1, 0);
     if (!ring->fifo)
         return AVERROR(ENOMEM);
 
@@ -93,45 +93,59 @@ static int ring_init(RingBuffer *ring, unsigned int capacity, int read_back_capa
 
 static void ring_destroy(RingBuffer *ring)
 {
-    av_fifo_freep(&ring->fifo);
+    av_fifo_freep2(&ring->fifo);
 }
 
 static void ring_reset(RingBuffer *ring)
 {
-    av_fifo_reset(ring->fifo);
+    av_fifo_reset2(ring->fifo);
     ring->read_pos = 0;
 }
 
 static int ring_size(RingBuffer *ring)
 {
-    return av_fifo_size(ring->fifo) - ring->read_pos;
+    return av_fifo_can_read(ring->fifo) - ring->read_pos;
 }
 
 static int ring_space(RingBuffer *ring)
 {
-    return av_fifo_space(ring->fifo);
+    return av_fifo_can_write(ring->fifo);
 }
 
-static int ring_generic_read(RingBuffer *ring, void *dest, int buf_size, void (*func)(void*, void*, int))
+static int ring_read(RingBuffer *ring, void *dest, int buf_size)
 {
-    int ret;
+    int ret = 0;
 
     av_assert2(buf_size <= ring_size(ring));
-    ret = av_fifo_generic_peek_at(ring->fifo, dest, ring->read_pos, buf_size, func);
+    if (dest)
+        ret = av_fifo_peek(ring->fifo, dest, buf_size, ring->read_pos);
     ring->read_pos += buf_size;
 
     if (ring->read_pos > ring->read_back_capacity) {
-        av_fifo_drain(ring->fifo, ring->read_pos - ring->read_back_capacity);
+        av_fifo_drain2(ring->fifo, ring->read_pos - ring->read_back_capacity);
         ring->read_pos = ring->read_back_capacity;
     }
 
     return ret;
 }
 
-static int ring_generic_write(RingBuffer *ring, void *src, int size, int (*func)(void*, void*, int))
+static int wrapped_url_read(void *src, void *dst, size_t *size)
+{
+    URLContext *h   = src;
+    Context    *c   = h->priv_data;
+    int         ret;
+
+    ret = ffurl_read(c->inner, dst, *size);
+    *size             = ret > 0 ? ret : 0;
+    c->inner_io_error = ret < 0 ? ret : 0;
+
+    return c->inner_io_error;
+}
+
+static int ring_write(RingBuffer *ring, URLContext *h, size_t size)
 {
     av_assert2(size <= ring_space(ring));
-    return av_fifo_generic_write(ring->fifo, src, size, func);
+    return av_fifo_write_from_cb(ring->fifo, wrapped_url_read, h, &size);
 }
 
 static int ring_size_of_read_back(RingBuffer *ring)
@@ -161,18 +175,6 @@ static int async_check_interrupt(void *arg)
     return c->abort_request;
 }
 
-static int wrapped_url_read(void *src, void *dst, int size)
-{
-    URLContext *h   = src;
-    Context    *c   = h->priv_data;
-    int         ret;
-
-    ret = ffurl_read(c->inner, dst, size);
-    c->inner_io_error = ret < 0 ? ret : 0;
-
-    return ret;
-}
-
 static void *async_buffer_task(void *arg)
 {
     URLContext   *h    = arg;
@@ -221,7 +223,7 @@ static void *async_buffer_task(void *arg)
         pthread_mutex_unlock(&c->mutex);
 
         to_copy = FFMIN(4096, fifo_space);
-        ret = ring_generic_write(ring, (void *)h, to_copy, wrapped_url_read);
+        ret = ring_write(ring, h, to_copy);
 
         pthread_mutex_lock(&c->mutex);
         if (ret <= 0) {
@@ -327,11 +329,11 @@ static int async_close(URLContext *h)
     return 0;
 }
 
-static int async_read_internal(URLContext *h, void *dest, int size, int read_complete,
-                               void (*func)(void*, void*, int))
+static int async_read_internal(URLContext *h, void *dest, int size)
 {
     Context      *c       = h->priv_data;
     RingBuffer   *ring    = &c->ring;
+    int     read_complete = !dest;
     int           to_read = size;
     int           ret     = 0;
 
@@ -346,8 +348,8 @@ static int async_read_internal(URLContext *h, void *dest, int size, int read_com
         fifo_size = ring_size(ring);
         to_copy   = FFMIN(to_read, fifo_size);
         if (to_copy > 0) {
-            ring_generic_read(ring, dest, to_copy, func);
-            if (!func)
+            ring_read(ring, dest, to_copy);
+            if (dest)
                 dest = (uint8_t *)dest + to_copy;
             c->logical_pos += to_copy;
             to_read        -= to_copy;
@@ -376,11 +378,7 @@ static int async_read_internal(URLContext *h, void *dest, int size, int read_com
 
 static int async_read(URLContext *h, unsigned char *buf, int size)
 {
-    return async_read_internal(h, buf, size, 0, NULL);
-}
-
-static void fifo_do_not_copy_func(void* dest, void* src, int size) {
-    // do not copy
+    return async_read_internal(h, buf, size);
 }
 
 static int64_t async_seek(URLContext *h, int64_t pos, int whence)
@@ -422,7 +420,7 @@ static int64_t async_seek(URLContext *h, int64_t pos, int whence)
 
         if (pos_delta > 0) {
             // fast seek forwards
-            async_read_internal(h, NULL, pos_delta, 1, fifo_do_not_copy_func);
+            async_read_internal(h, NULL, pos_delta);
         } else {
             // fast seek backwards
             ring_drain(ring, pos_delta);