Add V8ObjectBuilder helper and use in modules/crypto/

Source/bindings/core/v8/V8ObjectBuilder.cpp

Index: Source/bindings/core/v8/V8ObjectBuilder.cpp
diff --git a/Source/bindings/core/v8/V8ObjectBuilder.cpp b/Source/bindings/core/v8/V8ObjectBuilder.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..fa8d3ce8b5209d1c34d4bd20025ebfc1f2340738
--- /dev/null
+++ b/Source/bindings/core/v8/V8ObjectBuilder.cpp
@@ -0,0 +1,64 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "bindings/core/v8/V8ObjectBuilder.h"
+
+#include "bindings/core/v8/V8Binding.h"
+
+namespace blink {
+
+V8ObjectBuilder::V8ObjectBuilder(ScriptState* scriptState)
+    : m_scriptState(scriptState)
+    , m_object(v8::Object::New(scriptState->isolate()))
+{
+}
+
+ScriptValue V8ObjectBuilder::scriptValue() const
+{
+    return ScriptValue(m_scriptState.get(), m_object);
+}
+
+V8ObjectBuilder& V8ObjectBuilder::add(String name, const ScriptValue& value)
+{
+    add(name, value.v8Value());
+    return *this;
+}
+
+V8ObjectBuilder& V8ObjectBuilder::add(String name, const V8ObjectBuilder& value)
+{
+    add(name, value.v8Value());
+    return *this;
+}
+
+V8ObjectBuilder& V8ObjectBuilder::addNull(String name)
+{
+    add(name, v8::Null(m_scriptState->isolate()));
+    return *this;
+}
+
+V8ObjectBuilder& V8ObjectBuilder::addBoolean(String name, bool value)
+{
+    add(name, value ? v8::True(m_scriptState->isolate()) : v8::False(m_scriptState->isolate()));
+    return *this;
+}
+
+V8ObjectBuilder& V8ObjectBuilder::addNumber(String name, double value)
+{
+    add(name, v8::Number::New(m_scriptState->isolate(), value));
+    return *this;
+}
+
+V8ObjectBuilder& V8ObjectBuilder::addString(String name, String value)
+{
+    add(name, v8String(m_scriptState->isolate(), value));
+    return *this;
+}
+
+void V8ObjectBuilder::add(String name, v8::Local<v8::Value> value)
+{
+    m_object->ForceSet(m_scriptState->context(), v8String(m_scriptState->isolate(), name), value);

[bashi, 2015/03/25 01:09:25]

Just a note: In the future, we might want to provide a way to ensure that all
addXXX() succeed.

void V8ObjectBuilder::add(...) {
  m_errorOccurred = m_object->ForceSet(...).IsEmpty() || m_errorOccurred;
}

bool V8ObjectBuilder::errorOccurred() { return m_errorOccurred; }

And return an empty value on failure when v8Value() called.

[Jens Widell, 2015/03/25 11:16:04]

I implemented this with a slight variation: letting empty m_object mean "has
failed" (in which case no further ForceSet()s are performed) and clearing
m_object upon failure. Failure to allocate m_object in the first place is thus
automatically detected as an error too, and an empty value is returned in the
end if anything has failed.

+}
+
+} // namespace blink