[FFmpeg-devel] [RFC] url_write()

[Michael Niedermayer]

On Tue, Oct 05, 2010 at 11:43:13PM +0200, Reimar D?ffinger wrote:
> On Tue, Oct 05, 2010 at 10:04:43PM +0200, Michael Niedermayer wrote:
> >  int url_write(URLContext *h, const unsigned char *buf, int size)
> >  {
> > -    int ret;
> > +    int len= 0;
> > +    int fast_retries= 5;
> >      if (!(h->flags & (URL_WRONLY | URL_RDWR)))
> >          return AVERROR(EIO);
> >      /* avoid sending too big packets */
> >      if (h->max_packet_size && size > h->max_packet_size)
> >          return AVERROR(EIO);
> > -    ret = h->prot->url_write(h, buf, size);
> > -    return ret;
> > +
> > +    while(len<size){
> > +        int ret= h->prot->url_write(h, buf+len, size-len);
> > +        if (ret == AVERROR(EAGAIN)) {
> > +            ret= 0;
> > +            if (fast_retries){
> > +                fast_retries--;
> > +            }else
> > +                usleep(1000);
> > +        } else if (ret < 1)
> > +            return ret < 0 ? ret : len;
> > +        if (ret)
> > +           fast_retries = FFMAX(fast_retries, 2);
> > +        len += ret;
> > +    }
> > +    return len;
> 
> Very strange space-placement, particularly since the
> "url_read_complete" does not have it.
> Obviously due to some clean up, but I guess both should be
> identical.

its because i copy and pasted part and wrote part by hand then removed
the fast_retries and then decided to put it back


> How about a
> static inline int retry_transfer_wrapper(URLContext *h, const unsigned char *buf, int size,
>                                          int (*transfer_func)(URLContext *h, const unsigned char *buf, int size))
> 
> And using it for both instead of duplicating it?

will commit below soon if you are ok with it

commit 39f392b6de49d3135364b5ce119c7453549bb6f5
Author: Michael Niedermayer <michaelni at gmx.at>
Date:   Wed Oct 6 00:21:20 2010 +0200

    Use retry_transfer_wrapper() in url_write() as its callers do not expect it to stop in the middle.

diff --git a/libavformat/avio.c b/libavformat/avio.c
index bf0d9d8..2dae492 100644
--- a/libavformat/avio.c
+++ b/libavformat/avio.c
@@ -252,8 +252,8 @@ int url_write(URLContext *h, const unsigned char *buf, int size)
     /* avoid sending too big packets */
     if (h->max_packet_size && size > h->max_packet_size)
         return AVERROR(EIO);
-    ret = h->prot->url_write(h, buf, size);
-    return ret;
+
+    return retry_transfer_wrapper(h, buf, size, h->prot->url_write);
 }

 int64_t url_seek(URLContext *h, int64_t pos, int whence)

commit 1a617a6b38e742ed1cb77dbe1128f375ee1af4ba
Author: Michael Niedermayer <michaelni at gmx.at>
Date:   Wed Oct 6 00:18:34 2010 +0200

    Factor retry_transfer_wrapper() out of url_read_complete()

diff --git a/libavformat/avio.c b/libavformat/avio.c
index 4399878..bf0d9d8 100644
--- a/libavformat/avio.c
+++ b/libavformat/avio.c
@@ -215,14 +215,15 @@ int url_read(URLContext *h, unsigned char *buf, int size)
     return ret;
 }

-int url_read_complete(URLContext *h, unsigned char *buf, int size)
+static inline int retry_transfer_wrapper(URLContext *h, unsigned char *buf, int size,
+                                         int (*transfer_func)(URLContext *h, unsigned char *buf, int size))
 {
     int ret, len;
     int fast_retries = 5;

     len = 0;
     while (len < size) {
-        ret = url_read(h, buf+len, size-len);
+        ret = transfer_func(h, buf+len, size-len);
         if (ret == AVERROR(EAGAIN)) {
             ret = 0;
             if (fast_retries)
@@ -238,6 +239,11 @@ int url_read_complete(URLContext *h, unsigned char *buf, int size)
     return len;
 }

+int url_read_complete(URLContext *h, unsigned char *buf, int size)
+{
+    return retry_transfer_wrapper(h, buf, size, url_read);
+}
+
 int url_write(URLContext *h, const unsigned char *buf, int size)
 {
     int ret;

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Why not whip the teacher when the pupil misbehaves? -- Diogenes of Sinope
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