Improve Crypto::getRandomValues exception messages.

Source/bindings/v8/ExceptionState.h

Index: Source/bindings/v8/ExceptionState.h
diff --git a/Source/bindings/v8/ExceptionState.h b/Source/bindings/v8/ExceptionState.h
index 576d370ee2553c3176ddb9e58bb33964d484633f..de1300b5ae72b0e319611aaf73bf4b8e6c8a374e 100644
--- a/Source/bindings/v8/ExceptionState.h
+++ b/Source/bindings/v8/ExceptionState.h
@@ -44,11 +44,39 @@ typedef int ExceptionCode;
 class ExceptionState {
     WTF_MAKE_NONCOPYABLE(ExceptionState);
 public:
+    enum Context {
+        ConstructionContext,
+        ExecutionContext,
+        DeletionContext,
+        GetterContext,
+        SetterContext,
+        UnknownContext, // FIXME: Remove this once we've flipped over to the new API.
+    };
+
     explicit ExceptionState(const v8::Handle<v8::Object>& creationContext, v8::Isolate* isolate)
         : m_code(0)
+        , m_context(UnknownContext)
+        , m_property(0)
+        , m_interface(0)
+        , m_creationContext(creationContext)
+        , m_isolate(isolate) { }
+
+    ExceptionState(Context context, const char* property, const char* interface, const v8::Handle<v8::Object>& creationContext, v8::Isolate* isolate)
+        : m_code(0)
+        , m_context(context)
+        , m_property(property)
+        , m_interface(interface)
         , m_creationContext(creationContext)
         , m_isolate(isolate) { }
 
+    ExceptionState(Context context, const char* interface, const v8::Handle<v8::Object>& creationContext, v8::Isolate* isolate)
+        : m_code(0)
+        , m_context(context)
+        , m_property(0)
+        , m_interface(interface)
+        , m_creationContext(creationContext)
+        , m_isolate(isolate) { ASSERT(m_executionContext == ExceptionStateForConstruction); }
+
     virtual void throwDOMException(const ExceptionCode&, const String& message);
     virtual void throwTypeError(const String& message);
     virtual void throwSecurityError(const String& sanitizedMessage, const String& unsanitizedMessage = String());
@@ -74,8 +102,15 @@ public:
         return true;
     }
 
+    Context context() { return m_context; }
+    const char* property() { return m_property; }
+    const char* interface() { return m_interface; }
+
 protected:
     ExceptionCode m_code;
+    Context m_context;
+    const char* m_property;
+    const char* m_interface;

[haraken, 2013/11/26 10:49:36]

Don't you want to use String instead of char*?

[Mike West, 2013/11/26 10:53:26]

I don't want the performance hit of converting to String unless we actually
throw an exception. This sort of thing has already popped up in a number of
microbenchmarks as potentially problematic, so I'm trying to preemptively avoid
it here.

 
 private:
     void setException(v8::Handle<v8::Value>);