Backout changeset 89f35d1fea6c (bug 539356) because of performance and correctness regressions

gfx/2d/UserData.h

@@ -26,16 +26,8 @@ public:
   /* Attaches untyped userData associated with key. destroy is called on destruction */
   void Add(UserDataKey *key, void *userData, destroyFunc destroy)
   {
-    for (int i=0; i<count; i++) {
-      if (key == entries[i].key) {
-        if (entries[i].destroy) {
-          entries[i].destroy(entries[i].userData);
-        }
-        entries[i].userData = userData;
-        entries[i].destroy = destroy;
-        return;
-      }
-    }
+    // XXX we should really warn if user data with key has already been added,
+    // since in that case Get() will return the old user data!
 
     // We could keep entries in a std::vector instead of managing it by hand
     // but that would propagate an stl dependency out which we'd rather not
@@ -82,21 +74,12 @@ public:
     return NULL;
   }
 
-  void Destroy()
-  {
-    for (int i=0; i<count; i++) {
-      if (entries[i].destroy) {
-        entries[i].destroy(entries[i].userData);
-      }
-    }
-    free(entries);
-    entries = NULL;
-    count = 0;
-  }
-
   ~UserData()
   {
-    Destroy();
+    for (int i=0; i<count; i++) {
+      entries[i].destroy(entries[i].userData);
+    }
+    free(entries);
   }
 
 private:

gfx/layers/Layers.h

@@ -167,10 +167,60 @@ public:
  * BasicLayerManager for such an implementation.
  */
 
-static void LayerManagerUserDataDestroy(void *data)
-{
-  delete static_cast<LayerUserData*>(data);
-}
+/**
+ * Helper class to manage user data for layers and LayerManagers.
+ */
+class THEBES_API LayerUserDataSet {
+public:
+  LayerUserDataSet() : mKey(nsnull) {}
+
+  void Set(void* aKey, LayerUserData* aValue)
+  {
+    NS_ASSERTION(!mKey || mKey == aKey,
+                 "Multiple LayerUserData objects not supported");
+    mKey = aKey;
+    mValue = aValue;
+  }
+  /**
+   * This can be used anytime. Ownership passes to the caller!
+   */
+  LayerUserData* Remove(void* aKey)
+  {
+    if (mKey == aKey) {
+      mKey = nsnull;
+      LayerUserData* d = mValue.forget();
+      return d;
+    }
+    return nsnull;
+  }
+  /**
+   * This getter can be used anytime.
+   */
+  bool Has(void* aKey)
+  {
+    return mKey == aKey;
+  }
+  /**
+   * This getter can be used anytime. Ownership is retained by this object.
+   */
+  LayerUserData* Get(void* aKey)
+  {
+    return mKey == aKey ? mValue.get() : nsnull;
+  }
+
+  /**
+   * Clear out current user data.
+   */
+  void Clear()
+  {
+    mKey = nsnull;
+    mValue = nsnull;
+  }
+
+private:
+  void* mKey;
+  nsAutoPtr<LayerUserData> mValue;
+};
 
 /**
  * A LayerManager controls a tree of layers. All layers in the tree
@@ -220,7 +270,7 @@ public:
    * for its widget going away.  After this call, only user data calls
    * are valid on the layer manager.
    */
-  virtual void Destroy() { mDestroyed = true; mUserData.Destroy(); }
+  virtual void Destroy() { mDestroyed = true; mUserData.Clear(); }
   bool IsDestroyed() { return mDestroyed; }
 
   virtual ShadowLayerForwarder* AsShadowForwarder()
@@ -414,32 +464,23 @@ public:
    * initially null. Ownership pases to the layer manager.
    */
   void SetUserData(void* aKey, LayerUserData* aData)
-  {
-    mUserData.Add(static_cast<gfx::UserDataKey*>(aKey), aData, LayerManagerUserDataDestroy);
-  }
+  { mUserData.Set(aKey, aData); }
   /**
    * This can be used anytime. Ownership passes to the caller!
    */
   nsAutoPtr<LayerUserData> RemoveUserData(void* aKey)
-  { 
-    nsAutoPtr<LayerUserData> d(static_cast<LayerUserData*>(mUserData.Remove(static_cast<gfx::UserDataKey*>(aKey)))); 
-    return d;
-  }
+  { nsAutoPtr<LayerUserData> d(mUserData.Remove(aKey)); return d; }
   /**
    * This getter can be used anytime.
    */
   bool HasUserData(void* aKey)
-  {
-    return GetUserData(aKey);
-  }
+  { return mUserData.Has(aKey); }
   /**
    * This getter can be used anytime. Ownership is retained by the layer
    * manager.
    */
   LayerUserData* GetUserData(void* aKey)
-  { 
-    return static_cast<LayerUserData*>(mUserData.Get(static_cast<gfx::UserDataKey*>(aKey)));
-  }
+  { return mUserData.Get(aKey); }
 
   /**
    * Flag the next paint as the first for a document.
@@ -489,7 +530,7 @@ public:
 
 protected:
   nsRefPtr<Layer> mRoot;
-  gfx::UserData mUserData;
+  LayerUserDataSet mUserData;
   bool mDestroyed;
   bool mSnapEffectiveTransforms;
 
@@ -748,32 +789,23 @@ public:
    * initially null. Ownership pases to the layer manager.
    */
   void SetUserData(void* aKey, LayerUserData* aData)
-  { 
-    mUserData.Add(static_cast<gfx::UserDataKey*>(aKey), aData, LayerManagerUserDataDestroy);
-  }
+  { mUserData.Set(aKey, aData); }
   /**
    * This can be used anytime. Ownership passes to the caller!
    */
   nsAutoPtr<LayerUserData> RemoveUserData(void* aKey)
-  { 
-    nsAutoPtr<LayerUserData> d(static_cast<LayerUserData*>(mUserData.Remove(static_cast<gfx::UserDataKey*>(aKey)))); 
-    return d;
-  }
+  { nsAutoPtr<LayerUserData> d(mUserData.Remove(aKey)); return d; }
   /**
    * This getter can be used anytime.
    */
   bool HasUserData(void* aKey)
-  {
-    return GetUserData(aKey);
-  }
+  { return mUserData.Has(aKey); }
   /**
    * This getter can be used anytime. Ownership is retained by the layer
    * manager.
    */
   LayerUserData* GetUserData(void* aKey)
-  { 
-    return static_cast<LayerUserData*>(mUserData.Get(static_cast<gfx::UserDataKey*>(aKey)));
-  }
+  { return mUserData.Get(aKey); }
 
   /**
    * |Disconnect()| is used by layers hooked up over IPC.  It may be
@@ -959,7 +991,7 @@ protected:
   Layer* mPrevSibling;
   void* mImplData;
   nsRefPtr<Layer> mMaskLayer;
-  gfx::UserData mUserData;
+  LayerUserDataSet mUserData;
   nsIntRegion mVisibleRegion;
   gfx3DMatrix mTransform;
   gfx3DMatrix mEffectiveTransform;