From 933dec0e29ec4d2cb83474279a6c52d62fdb7310 Mon Sep 17 00:00:00 2001 From: Martin Storsjö Date: Thu, 5 Feb 2015 15:06:42 +0200 Subject: file: Add an option for following a file that is being written MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- doc/protocols.texi | 11 +++++++++++ libavformat/file.c | 4 ++++ libavformat/version.h | 2 +- 3 files changed, 16 insertions(+), 1 deletion(-) diff --git a/doc/protocols.texi b/doc/protocols.texi index c0663ac76a..c136c74e41 100644 --- a/doc/protocols.texi +++ b/doc/protocols.texi @@ -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. diff --git a/libavformat/file.c b/libavformat/file.c index 4f581cfae7..8683c1bedd 100644 --- a/libavformat/file.c +++ b/libavformat/file.c @@ -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; } diff --git a/libavformat/version.h b/libavformat/version.h index 75d765b3e6..aae1e23163 100644 --- a/libavformat/version.h +++ b/libavformat/version.h @@ -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, \ -- cgit v1.2.3