Initial error handling code

include/core/SkFlattenable.h

Index: include/core/SkFlattenable.h
diff --git a/include/core/SkFlattenable.h b/include/core/SkFlattenable.h
index 58e69fd416cb049b56d881942f6f77ebb676e93d..ca05adf96675356feb1675d8633a4f72c6bfc2cf 100644
--- a/include/core/SkFlattenable.h
+++ b/include/core/SkFlattenable.h
@@ -16,7 +16,7 @@ class SkFlattenableReadBuffer;
 class SkFlattenableWriteBuffer;
 
 #define SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(flattenable) \
-        SkFlattenable::Registrar(#flattenable, flattenable::CreateProc);
+        SkFlattenable::Registrar(#flattenable, flattenable::CreateProc, flattenable::GetType());
 
 #define SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP() static void InitializeFlattenables();
 
@@ -35,6 +35,14 @@ class SkFlattenableWriteBuffer;
         return SkNEW_ARGS(flattenable, (buffer)); \
     }
 
+/** For SkFlattenable derived objects with a valid type
+    This macro should only be used in base class objects in core
+  */
+#define SK_DEFINE_FLATTENABLE_TYPE(flattenable) \
+    static Type GetType() { \

[Stephen White, 2013/10/17 15:27:56]

+1 for the scoped enum. I like it! But I think this function should be
GetFlattenableType(), in order to avoid polluting the subclass's namespace with
something that sounds pretty generic. GetType() could imply it was the derived
class's type, where in actuality it's the base class's.

[sugoi1, 2013/10/17 15:33:55]

Done.

+        return k##flattenable##_Type; \
+    }
+
 /** \class SkFlattenable
 
  SkFlattenable is the base class for objects that need to be flattened
@@ -43,6 +51,19 @@ class SkFlattenableWriteBuffer;
  */
 class SK_API SkFlattenable : public SkRefCnt {
 public:
+    enum Type {
+        kSkColorFilter_Type,
+        kSkDrawLooper_Type,
+        kSkImageFilter_Type,
+        kSkMaskFilter_Type,
+        kSkPathEffect_Type,
+        kSkPixelRef_Type,
+        kSkRasterizer_Type,
+        kSkShader_Type,
+        kSkUnitMapper_Type,
+        kSkXfermode_Type,
+    };
+
     SK_DECLARE_INST_COUNT(SkFlattenable)
 
     typedef SkFlattenable* (*Factory)(SkFlattenableReadBuffer&);
@@ -55,14 +76,20 @@ public:
      */
     virtual Factory getFactory() = 0;
 
+    /** Returns the name of the object's class
+      */
+    const char* getTypeName() { return FactoryToName(getFactory()); }
+
     static Factory NameToFactory(const char name[]);
     static const char* FactoryToName(Factory);
-    static void Register(const char name[], Factory);
+    static bool NameToType(const char name[], Type* type);
+
+    static void Register(const char name[], Factory, Type);
 
     class Registrar {
     public:
-        Registrar(const char name[], Factory factory) {
-            SkFlattenable::Register(name, factory);
+        Registrar(const char name[], Factory factory, Type type) {
+            SkFlattenable::Register(name, factory, type);
         }
     };
 
@@ -75,7 +102,7 @@ protected:
     virtual void flatten(SkFlattenableWriteBuffer&) const;
 
 private:
-    static void InitializeFlattenables();
+    static void InitializeFlattenablesIfNeeded();
 
     friend class SkGraphics;
     friend class SkFlattenableWriteBuffer;