From 3d367e009c22e390c021bd6b2be32adc641222e7 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Mon, 29 Jan 2018 13:47:05 +0100
Subject: [PATCH] mp_image: factor buffer referencing

Reduce the trivial but still annoying code duplication in
mp_image_new_ref(), which has to create new buffer references and deal
with possible failure of creating them. The tricky part is that if
creating a reference fails, we must set the target to NULL, so that
unreferencing the failed new mp_image reference does not release the
buffer references of the original mp_image. For the same reason, the
code can't jump to error handling when it can't create a new reference,
and has to set a flag instead.
---
 video/mp_image.c | 32 +++++++++++++++-----------------
 1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/video/mp_image.c b/video/mp_image.c
index 4da576c400..0c07fd3098 100644
--- a/video/mp_image.c
+++ b/video/mp_image.c
@@ -296,6 +296,16 @@ void mp_image_unref_data(struct mp_image *img)
     }
 }
 
+static bool ref_buffer(AVBufferRef **dst)
+{
+    if (*dst) {
+        *dst = av_buffer_ref(*dst);
+        if (!*dst)
+            return false;
+    }
+    return true;
+}
+
 // Return a new reference to img. The returned reference is owned by the caller,
 // while img is left untouched.
 struct mp_image *mp_image_new_ref(struct mp_image *img)
@@ -311,24 +321,12 @@ struct mp_image *mp_image_new_ref(struct mp_image *img)
     *new = *img;
 
     bool fail = false;
-    for (int p = 0; p < MP_MAX_PLANES; p++) {
-        if (new->bufs[p]) {
-            new->bufs[p] = av_buffer_ref(new->bufs[p]);
-            if (!new->bufs[p])
-                fail = true;
-        }
-    }
-    if (new->hwctx) {
-        new->hwctx = av_buffer_ref(new->hwctx);
-        if (!new->hwctx)
-            fail = true;
-    }
+    for (int p = 0; p < MP_MAX_PLANES; p++)
+        fail |= !ref_buffer(&new->bufs[p]);
+
+    fail |= !ref_buffer(&new->hwctx);
+    fail |= !ref_buffer(&new->icc_profile);
 
-    if (new->icc_profile) {
-        new->icc_profile = av_buffer_ref(new->icc_profile);
-        if (!new->icc_profile)
-            fail = true;
-    }
 
     if (!fail)
         return new;