* image.c: Fix animation cache signature memory leak.

Fix some other minor performance problems while we're at it.
(imagemagick_create_cache): Clear just the members that
need clearing.  Don't set update_time, as caller does that now.
(imagemagick_prune_animation_cache, imagemagick_get_animation_cache):
Simplify by using pointer-to-pointer instead of a prev pointer.
(imagemagick_prune_animation_cache): Use make_emacs_time rather
than EMACS_TIME_FROM_DOUBLE, and DestroyString rather than free.
(imagemagick_get_animation_cache): Don't xstrdup the image signature;
it's already a copy.  Free the signature probe unless it's cached.

2 files changed, 39 insertions, 34 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 0203ce636ef..c5a6f4d19c3 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,16 @@
 2013-08-19  Paul Eggert  <eggert@cs.ucla.edu>
 
+        * image.c: Fix animation cache signature memory leak.
+        Fix some other minor performance problems while we're at it.
+        (imagemagick_create_cache): Clear just the members that
+        need clearing.  Don't set update_time, as caller does that now.
+        (imagemagick_prune_animation_cache, imagemagick_get_animation_cache):
+        Simplify by using pointer-to-pointer instead of a prev pointer.
+        (imagemagick_prune_animation_cache): Use make_emacs_time rather
+        than EMACS_TIME_FROM_DOUBLE, and DestroyString rather than free.
+        (imagemagick_get_animation_cache): Don't xstrdup the image signature;
+        it's already a copy.  Free the signature probe unless it's cached.
+
         * process.c (handle_child_signal): Fix crash; deleted pid (Bug#15106).
         This was introduced by my 2013-08-12 fix for Bug#15035.
 
diff --git a/src/image.c b/src/image.c
index a8210e2414a..68d78fc9eef 100644
--- a/src/image.c
+++ b/src/image.c
@@ -7890,9 +7890,11 @@ static struct animation_cache *animation_cache = NULL;
 static struct animation_cache *
 imagemagick_create_cache (char *signature)
 {
-  struct animation_cache *cache = xzalloc (sizeof *cache);
+  struct animation_cache *cache = xmalloc (sizeof *cache);
   cache->signature = signature;
-  cache->update_time = current_emacs_time ();
+  cache->wand = 0;
+  cache->index = 0;
+  cache->next = 0;
   return cache;
 }
 
@@ -7900,30 +7902,22 @@ imagemagick_create_cache (char *signature)
 static void
 imagemagick_prune_animation_cache (void)
 {
-  struct animation_cache *cache = animation_cache;
-  struct animation_cache *prev = NULL;
+  struct animation_cache **pcache = &animation_cache;
   EMACS_TIME old = sub_emacs_time (current_emacs_time (),
-                                   EMACS_TIME_FROM_DOUBLE (60));
+                                   make_emacs_time (60, 0));
 
-  while (cache)
+  while (*pcache)
     {
-      if (EMACS_TIME_LT (cache->update_time, old))
+      struct animation_cache *cache = *pcache;
+      if (EMACS_TIME_LE (old, cache->update_time))
+        pcache = &cache->next;
+      else
         {
-          struct animation_cache *this_cache = cache;
-          free (cache->signature);
+          DestroyString (cache->signature);
           if (cache->wand)
             DestroyMagickWand (cache->wand);
-          if (prev)
-            prev->next = cache->next;
-          else
-            animation_cache = cache->next;
-          cache = cache->next;
-          free (this_cache);
-        }
-      else
-        {
-          prev = cache;
-          cache = cache->next;
+          *pcache = cache->next;
+          xfree (cache);
         }
     }
 }
@@ -7931,26 +7925,26 @@ imagemagick_prune_animation_cache (void)
 static struct animation_cache *
 imagemagick_get_animation_cache (MagickWand *wand)
 {
-  char *signature = xstrdup (MagickGetImageSignature (wand));
+  char *signature = MagickGetImageSignature (wand);
   struct animation_cache *cache;
+  struct animation_cache **pcache = &animation_cache;
 
   imagemagick_prune_animation_cache ();
   cache = animation_cache;
 
-  if (! cache)
-    {
-      animation_cache = imagemagick_create_cache (signature);
-      return animation_cache;
-    }
-
-  while (strcmp(signature, cache->signature) &&
-         cache->next)
-    cache = cache->next;
-
-  if (strcmp(signature, cache->signature))
+  for (pcache = &animation_cache; *pcache; pcache = &cache->next)
     {
-      cache->next = imagemagick_create_cache (signature);
-      return cache->next;
+      cache = *pcache;
+      if (! cache)
+        {
+          *pcache = cache = imagemagick_create_cache (signature);
+          break;
+        }
+      if (strcmp (signature, cache->signature) == 0)
+        {
+          DestroyString (signature);
+          break;
+        }
     }
 
   cache->update_time = current_emacs_time ();