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

chrome/renderer/extensions/v8_schema_registry.cc

Index: chrome/renderer/extensions/v8_schema_registry.cc
diff --git a/chrome/renderer/extensions/v8_schema_registry.cc b/chrome/renderer/extensions/v8_schema_registry.cc
new file mode 100644
index 0000000000000000000000000000000000000000..35a22b29365d1ef7f07d65621d993df4427e0045
--- /dev/null
+++ b/chrome/renderer/extensions/v8_schema_registry.cc
@@ -0,0 +1,56 @@
+// 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.
+
+#include "chrome/renderer/extensions/v8_schema_registry.h"
+
+#include "base/logging.h"
+#include "base/values.h"
+#include "chrome/common/extensions/api/extension_api.h"
+#include "content/public/renderer/v8_value_converter.h"
+
+using content::V8ValueConverter;
+
+namespace extensions {
+
+V8SchemaRegistry::V8SchemaRegistry() : context_(v8::Context::New()) {}
+
+V8SchemaRegistry::~V8SchemaRegistry() {
+  for (SchemaCache::iterator i = schema_cache_.begin();
+      i != schema_cache_.end(); ++i) {
+    i->second.Dispose();
+  }
+  context_.Dispose();
+}
+
+v8::Handle<v8::Array> V8SchemaRegistry::GetSchemas(
+    const std::set<std::string>& apis) {
+  v8::Context::Scope context_scope(context_);
+  v8::Handle<v8::Array> v8_apis(v8::Array::New(apis.size()));
+  size_t api_index = 0;
+  for (std::set<std::string>::const_iterator i = apis.begin(); i != apis.end();
+      ++i) {
+    v8_apis->Set(api_index++, GetSchema(*i));
+  }
+  return v8_apis;
+}
+
+v8::Handle<v8::Object> V8SchemaRegistry::GetSchema(const std::string& api) {
+  SchemaCache::iterator maybe_schema = schema_cache_.find(api);
+  if (maybe_schema != schema_cache_.end())
+    return maybe_schema->second;
+
+  const base::DictionaryValue* schema =
+      ExtensionAPI::GetInstance()->GetSchema(api);
+  CHECK(schema) << api;
+
+  scoped_ptr<V8ValueConverter> v8_value_converter(V8ValueConverter::create());
+  v8::Persistent<v8::Object> v8_schema =
+      v8::Persistent<v8::Object>::New(v8::Handle<v8::Object>::Cast(
+          v8_value_converter->ToV8Value(schema, context_)));
+  CHECK(!v8_schema.IsEmpty());
+  schema_cache_[api] = v8_schema;
+  return v8_schema;
+}
+
+}  // namespace extensions