[FFmpeg-devel] [PATCH] Making process of uuid-xmp faster.

[Chen Meng]

From baee22d71825128f74beb15122cd786f8d89f13f Mon Sep 17 00:00:00 2001
From: Chen Meng <mengchen.mc at alibaba-inc.com>
Date: Tue, 8 Nov 2016 22:58:44 +0800
Subject: [PATCH] Take the error code in return.

---
 libavformat/mov.c | 30 ++++++++++++++----------------
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 388cd1f..c86252c 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -4529,30 +4529,28 @@ static int mov_read_uuid(MOVContext *c, AVIOContext *pb, MOVAtom atom)
         uint8_t *buffer;
         size_t len = atom.size - sizeof(uuid);
 
-        buffer = av_mallocz(len + 1);
-        if (!buffer) {
-            return AVERROR(ENOMEM);
-        }
-
         if (c->export_xmp) {
+            buffer = av_mallocz(len + 1);
+            if (!buffer) {
+                return AVERROR(ENOMEM);
+            }
             ret = avio_read(pb, buffer, len);
-            if (ret != len) {
+            if (ret < 0) {
+                av_free(buffer);
+                return ret;
+            } else if (ret != len) {
                 av_free(buffer);
                 return AVERROR_INVALIDDATA;
             }
-        } else {
-            // skip all uuid atom, which makes it fast for long uuid-xmp file 
-            ret = avio_seek(pb, len, SEEK_CUR);
-        }
-        if (ret < 0) {
-            av_free(buffer);
-            return ret;
-        }
-        if (c->export_xmp) {
             buffer[len] = '\0';
             av_dict_set(&c->fc->metadata, "xmp", buffer, 0);
+            av_free(buffer);
+        } else {
+            // skip all uuid atom, which makes it fast for long uuid-xmp file
+            ret = avio_seek(pb, len, SEEK_CUR);
+            if (ret < 0) 
+                return ret;
         }
-        av_free(buffer);
     }
     return 0;
 }
-- 
2.10.2


------------------------------------------------------------------From:Michael Niedermayer <michael at niedermayer.cc>Time:2016 Nov 8 (Tue) 20:10To:FFmpeg development discussions and patches <ffmpeg-devel at ffmpeg.org>Subject:Re: [FFmpeg-devel] [PATCH] Making process of uuid-xmp faster.
On Tue, Nov 08, 2016 at 04:34:13PM +0800, Chen Meng wrote:
> ---
>  libavformat/mov.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index f06de06..388cd1f 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -4533,13 +4533,20 @@ static int mov_read_uuid(MOVContext *c, AVIOContext *pb, MOVAtom atom)
>          if (!buffer) {
>              return AVERROR(ENOMEM);
>          }
> -        ret = avio_read(pb, buffer, len);
> +
> +        if (c->export_xmp) {
> +            ret = avio_read(pb, buffer, len);
> +            if (ret != len) {
> +                av_free(buffer);
> +                return AVERROR_INVALIDDATA;
> +            }

this looses the error code in ret

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Its not that you shouldnt use gotos but rather that you should write
readable code and code with gotos often but not always is less readable

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