Make a process-wide cache for the v8::Value representation of extension APIs.

chrome/renderer/extensions/v8_schema_registry.h

+// Copyright (c) 2012 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.
+
+#ifndef CHROME_RENDERER_EXTENSIONS_V8_SCHEMA_REGISTRY_H_
+#define CHROME_RENDERER_EXTENSIONS_V8_SCHEMA_REGISTRY_H_
+#pragma once
+
+#include <map>
+#include <set>
+#include <string>
+
+#include "base/basictypes.h"
+#include "v8/include/v8.h"
+
+namespace extensions {
+
+// A registry for the v8::Value representations of extension API schemas.
+// In a way, the v8 counterpart to ExtensionAPI.
+class V8SchemaRegistry {
+ public:
+  V8SchemaRegistry();
+  ~V8SchemaRegistry();
+
+  // Returns a v8::Array with all the schemas for the APIs in |apis|.
+  v8::Handle<v8::Array> GetSchemas(const std::set<std::string>& apis);
+
+ private:
+  // Returns a v8::Object for the schema for |api|, possibly from the cache.
+  v8::Handle<v8::Object> GetSchema(const std::string& api);
+
+  // Cache of schemas.
+  typedef std::map<std::string, v8::Persistent<v8::Object> > SchemaCache;
+  SchemaCache schema_cache_;
+
+  // Single per-instance v8::Context to create v8::Values.
+  v8::Persistent<v8::Context> context_;
+
+  DISALLOW_COPY_AND_ASSIGN(V8SchemaRegistry);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_RENDERER_EXTENSIONS_V8_SCHEMA_REGISTRY_H_