[FFmpeg-devel] [PATCH] avformat: added named pipe protocol

[Martin Sliwka]

Dne 15.6.2012 2:52, Michael Niedermayer napsal(a):
> On Thu, Jun 14, 2012 at 01:10:30PM +0200, Martin Sliwka wrote:
>> The new 'npipe' protocol is copy of 'file' protocol with two modifications:
>> 1) URLProtocol::url_seek is not set
>> 2) URLProtocol::url_open is set to npipe_open(...) which is same as
>> file_open(...)
>> except for protocol name it stripes from file name.
>>
>> New protocol is also very similar to already included 'pipe' protocol
>> which unfortunately can not be safely modified without breaking backward
>> compatibility.
>>
>> Reason for this change is that named pipes are not wokring as
>> seekable inputs.
>> Problem is that ffio_limit(...) incorrectly limits requested read
>> size because
>> avio_size(...) (it's fstat(...) in file_seek(...) in fact) can not
>> report correct
>> file size.
> the correct solution is to check if its a fifo and return 0 instead of
> the nonsense value from fstat()
> a patch doing that is welcome
>
> also thanks for the testcase
>

Ok, after some self-education in linux-way of doing things I made this 
simple and straightforward patch. I tested it on Windows and it works 
well. Some testing should be made on linux also but I'm unable to get 
linux version compiled.

Martin

---
  libavformat/file.c |    2 +-
  1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/libavformat/file.c b/libavformat/file.c
index db79b5c..59b755d 100644
--- a/libavformat/file.c
+++ b/libavformat/file.c
@@ -99,7 +99,7 @@ static int64_t file_seek(URLContext *h, int64_t pos, 
int whence)
      if (whence == AVSEEK_SIZE) {
          struct stat st;
          int ret = fstat(fd, &st);
-        return ret < 0 ? AVERROR(errno) : st.st_size;
+        return ret < 0 ? AVERROR(errno) : (S_ISFIFO(st.st_mode) ? 0 : 
st.st_size);
      }
      return lseek(fd, pos, whence);
  }
--
1.7.4.1