file: Add an option for following a file that is being written

Using this requires setting the rw_timeout option to make it
terminate, alternatively using the interrupt callback (if used via
the API).

Signed-off-by: Martin Storsjö <martin@martin.st>
pull/206/head
Martin Storsjö 10 years ago
parent ccea588f83
commit 933dec0e29
  1. 11
      doc/protocols.texi
  2. 4
      libavformat/file.c
  3. 2
      libavformat/version.h

@ -69,6 +69,17 @@ The av* tools default to the file protocol, that is a resource
specified with the name "FILE.mpeg" is interpreted as the URL
"file:FILE.mpeg".
This protocol accepts the following options:
@table @option
@item follow
If set to 1, the protocol will retry reading at the end of the file, allowing
reading files that still are being written. In order for this to terminate,
you either need to use the rw_timeout option, or use the interrupt callback
(for API users).
@end table
@section gopher
Gopher protocol.

@ -42,10 +42,12 @@ typedef struct FileContext {
const AVClass *class;
int fd;
int trunc;
int follow;
} FileContext;
static const AVOption file_options[] = {
{ "truncate", "Truncate existing files on write", offsetof(FileContext, trunc), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },
{ "follow", "Follow a file as it is being written", offsetof(FileContext, follow), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, AV_OPT_FLAG_DECODING_PARAM },
{ NULL }
};
@ -60,6 +62,8 @@ static int file_read(URLContext *h, unsigned char *buf, int size)
{
FileContext *c = h->priv_data;
int ret = read(c->fd, buf, size);
if (ret == 0 && c->follow)
return AVERROR(EAGAIN);
return (ret == -1) ? AVERROR(errno) : ret;
}

@ -31,7 +31,7 @@
#define LIBAVFORMAT_VERSION_MAJOR 57
#define LIBAVFORMAT_VERSION_MINOR 5
#define LIBAVFORMAT_VERSION_MICRO 1
#define LIBAVFORMAT_VERSION_MICRO 2
#define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
LIBAVFORMAT_VERSION_MINOR, \

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