diff mbox series

[FFmpeg-devel] avformat/file: seek back to initial position for fd protocol

Message ID tencent_736755C8C902EEAAE5487304A84173E87305@qq.com
State Accepted
Commit 5c3d2177e7be7dde69a83b1b394f57976c164c84
Headers show
Series [FFmpeg-devel] avformat/file: seek back to initial position for fd protocol | expand

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Commit Message

Zhao Zhili Dec. 18, 2023, 4:42 p.m. UTC 
From: Zhao Zhili <zhilizhao@tencent.com>

So user's fd can be passed to libavformat multiple times in sequence
without changing the position.

Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>
---
 libavformat/file.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

Comments

Anton Khirnov Dec. 18, 2023, 11:27 a.m. UTC | #1 
Quoting Zhao Zhili (2023-12-18 17:42:39)
> From: Zhao Zhili <zhilizhao@tencent.com>
> 
> So user's fd can be passed to libavformat multiple times in sequence
> without changing the position.
> 
> Signed-off-by: Zhao Zhili <zhilizhao@tencent.com>
> ---
>  libavformat/file.c | 14 +++++++++++++-
>  1 file changed, 13 insertions(+), 1 deletion(-)

Looks ok.
diff mbox series

Patch

diff --git a/libavformat/file.c b/libavformat/file.c
index cbdf48de0a..64df7ff6fb 100644
--- a/libavformat/file.c
+++ b/libavformat/file.c
@@ -98,6 +98,7 @@  typedef struct FileContext {
 #if HAVE_DIRENT_H
     DIR *dir;
 #endif
+    int64_t initial_pos;
 } FileContext;
 
 static const AVOption file_options[] = {
@@ -218,7 +219,12 @@  static int fd_dup(URLContext *h, int oldfd)
 static int file_close(URLContext *h)
 {
     FileContext *c = h->priv_data;
-    int ret = close(c->fd);
+    int ret;
+
+    if (c->initial_pos >= 0 && !h->is_streamed)
+        lseek(c->fd, c->initial_pos, SEEK_SET);
+
+    ret = close(c->fd);
     return (ret == -1) ? AVERROR(errno) : 0;
 }
 
@@ -286,6 +292,7 @@  static int file_open(URLContext *h, const char *filename, int flags)
 
     av_strstart(filename, "file:", &filename);
 
+    c->initial_pos = -1;
     if (flags & AVIO_FLAG_WRITE && flags & AVIO_FLAG_READ) {
         access = O_CREAT | O_RDWR;
         if (c->trunc)
@@ -494,6 +501,11 @@  static int fd_open(URLContext *h, const char *filename, int flags)
     if (c->fd == -1)
         return AVERROR(errno);
 
+    if (h->is_streamed)
+        c->initial_pos = -1;
+    else
+        c->initial_pos = lseek(c->fd, 0, SEEK_CUR);
+
     return 0;
 }