Cleanup dart to string conversions.

Source/WebCore/bindings/dart/DartUtilities.h

Index: Source/WebCore/bindings/dart/DartUtilities.h
diff --git a/Source/WebCore/bindings/dart/DartUtilities.h b/Source/WebCore/bindings/dart/DartUtilities.h
index 1da2c5e07c9f659ec81f950aa13e0d60ced71ac6..54b5027dbe29d094d1367b2cad759769c7b8c000 100644
--- a/Source/WebCore/bindings/dart/DartUtilities.h
+++ b/Source/WebCore/bindings/dart/DartUtilities.h
@@ -50,7 +50,19 @@ class ScriptExecutionContext;
 class SerializedScriptValue;
 class WebKitFlags;
 
-typedef HashMap<void*, Dart_Handle> DartDOMMap;
+class DartStringAdapter {
+public:
+    explicit DartStringAdapter(PassRefPtr<StringImpl> stringImpl)
+        : m_stringImpl(stringImpl)
+    {
+    }
+
+    operator String() const { return String(m_stringImpl); }
+    operator AtomicString() const { return AtomicString(m_stringImpl); }
+
+private:
+    RefPtr<StringImpl> m_stringImpl;
+};
 
 class DartUtilities {
 public:
@@ -61,16 +73,6 @@ public:
 
     static const char* htmlLibraryName;
 
-    static PassRefPtr<StringImpl> toStringImpl(Dart_Handle, ConversionFlag flag, Dart_Handle& exception);
-    // FIXME: we should get rid of this one in favour of toStringImpl.
-    static String dartStringToString(Dart_Handle object)
-    {
-        Dart_Handle exception = 0;
-        RefPtr<StringImpl> impl = toStringImpl(object, ConvertNone, exception);
-        ASSERT(!exception);
-        return String(impl.release());
-    }
-
     static Dart_Handle stringImplToDartString(StringImpl*);
     static Dart_Handle stringToDartString(const String&);
     static Dart_Handle stringToDartString(const AtomicString&);
@@ -96,6 +98,7 @@ public:
     static void extractMapElements(Dart_Handle map, Dart_Handle& exception, Vector<Dart_Handle>& keys, Vector<Dart_Handle>& values);
 
     static int64_t toInteger(Dart_Handle object, Dart_Handle& exception);
+    static String toString(Dart_Handle object);
     static void toMessagePortArray(Dart_Handle object, MessagePortArray&, ArrayBufferArray&, Dart_Handle& exception);
     static PassRefPtr<SerializedScriptValue> toSerializedScriptValue(Dart_Handle object, MessagePortArray*, ArrayBufferArray*, Dart_Handle& exception);
     static PassRefPtr<WebKitFlags> toWebKitFlags(Dart_Handle object, Dart_Handle& exception);
@@ -146,6 +149,17 @@ public:
 
     static Dart_Handle invokeUtilsMethod(const char* methodName, int argCount, Dart_Handle* args);
 
+    static DartStringAdapter dartToString(Dart_Handle object, Dart_Handle& exception)
+    {
+        // FIXME: [performance] need better treatment of String vs. AtomicString, cf. v8 implementation.
+        return DartStringAdapter(toStringImpl(object, exception));
+    }
+    static DartStringAdapter dartToStringWithNullCheck(Dart_Handle object, Dart_Handle& exception)

[Anton Muhin, 2012/06/26 16:52:28]

wdyt, do we need to distinguish those?  maybe we should just accept nulls?  my
main concern would be v8 may convert nulls to "null" string :)

[podivilov, 2012/06/26 18:07:38]

Passing nulls to c++ methods is a bit scary... Also we do want to throw
exceptions where real string should be provided.

+    {
+        if (Dart_IsNull(object))
+            return DartStringAdapter(0);
+        return dartToString(object, exception);
+    }
     static Dart_Handle stringToDart(const AtomicString& value, ConversionFlag flag = ConvertNone);
     static Dart_Handle stringToDart(const String& value, ConversionFlag flag = ConvertNone);
 
@@ -195,6 +209,9 @@ public:
 
     static PassRefPtr<SerializedScriptValue> dartToSerializedScriptValue(Dart_Handle, Dart_Handle& exception);
     static Dart_Handle serializedScriptValueToDart(SerializedScriptValue* value);
+
+private:
+    static PassRefPtr<StringImpl> toStringImpl(Dart_Handle object, Dart_Handle& exception);
 };
 
 class DartApiScope {