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 6cc76db46ed872379ef4ae07e8ec1819af29111c..5a6e2ae889ef6f19234a886766ab57bea4eaaaa3 100644
--- a/include/core/SkFlattenable.h
+++ b/include/core/SkFlattenable.h
@@ -16,7 +16,8 @@ class SkFlattenableReadBuffer;
 class SkFlattenableWriteBuffer;
 
 #define SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(flattenable) \
-        SkFlattenable::Registrar(#flattenable, flattenable::CreateProc);
+        SkFlattenable::Registrar(#flattenable, flattenable::CreateProc, \
+                                 flattenable::GetFlattenableType());
 
 #define SK_DECLARE_FLATTENABLE_REGISTRAR_GROUP() static void InitializeFlattenables();
 
@@ -35,6 +36,14 @@ 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 GetFlattenableType() { \
+        return k##flattenable##_Type; \
+    }
+
 /** \class SkFlattenable
 
  SkFlattenable is the base class for objects that need to be flattened
@@ -43,6 +52,19 @@ class SkFlattenableWriteBuffer;
  */
 class SK_API SkFlattenable : public SkRefCnt {
 public:
+    enum Type {
+        kSkColorFilter_Type,

[reed1, 2013/10/21 20:54:48]

If these are going to be inside an SkClass of some sort (as they are here), we
don't want the Sk on their name...

e.g.

kSkColorFilter_Type -> kColorFilter_Type

[mtklein, 2013/10/21 21:12:33]

Ah, this one's on me.  I think we want a slight style exception here.  These
guys have the full SkFoo name in them so that we can drop the full class name
into SK_DEFINE_FLATTENABLE_TYPE().  We can concat in a macro but not cut:

SK_DEFINE_FLATTENABLE_TYPE(SkDrawLooper)  ---> kSkDrawLooper_Type OK
SK_DEFINE_FLATTENABLE_TYPE(DrawLooper)    ---> kSkDrawLooper_Type OK
SK_DEFINE_FLATTENABLE_TYPE(DrawLooper)    ---> kDrawLooper_Type   OK
SK_DEFINE_FLATTENABLE_TYPE(SkDrawLooper)  ---> kDrawLooper_Type   NOPE

I personally thought it looked funny to see
SK_DEFINE_FLATTENABLE_TYPE(DrawLooper) inside SkDrawLooper.

+        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 +77,20 @@ public:
      */
     virtual Factory getFactory() const = 0;
 
+    /** Returns the name of the object's class
+      */
+    const char* getTypeName() const { 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 +103,7 @@ protected:
     virtual void flatten(SkFlattenableWriteBuffer&) const;
 
 private:
-    static void InitializeFlattenables();
+    static void InitializeFlattenablesIfNeeded();
 
     friend class SkGraphics;
     friend class SkFlattenableWriteBuffer;