1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef EXTENSIONS_RENDERER_OBJECT_BACKED_NATIVE_HANDLER_H_ 6 #define EXTENSIONS_RENDERER_OBJECT_BACKED_NATIVE_HANDLER_H_ 7 8 #include <string> 9 #include <vector> 10 11 #include "base/bind.h" 12 #include "base/memory/linked_ptr.h" 13 #include "extensions/renderer/native_handler.h" 14 #include "extensions/renderer/scoped_persistent.h" 15 #include "v8/include/v8-util.h" 16 #include "v8/include/v8.h" 17 18 namespace extensions { 19 class ScriptContext; 20 21 // An ObjectBackedNativeHandler is a factory for JS objects with functions on 22 // them that map to native C++ functions. Subclasses should call RouteFunction() 23 // in their constructor to define functions on the created JS objects. 24 class ObjectBackedNativeHandler : public NativeHandler { 25 public: 26 explicit ObjectBackedNativeHandler(ScriptContext* context); 27 virtual ~ObjectBackedNativeHandler(); 28 29 // Create an object with bindings to the native functions defined through 30 // RouteFunction(). 31 virtual v8::Handle<v8::Object> NewInstance() OVERRIDE; 32 33 v8::Isolate* GetIsolate() const; 34 35 protected: 36 typedef base::Callback<void(const v8::FunctionCallbackInfo<v8::Value>&)> 37 HandlerFunction; 38 39 // Installs a new 'route' from |name| to |handler_function|. This means that 40 // NewInstance()s of this ObjectBackedNativeHandler will have a property 41 // |name| which will be handled by |handler_function|. 42 void RouteFunction(const std::string& name, 43 const HandlerFunction& handler_function); 44 45 ScriptContext* context() const { return context_; } 46 47 virtual void Invalidate() OVERRIDE; 48 49 private: 50 // Callback for RouteFunction which routes the V8 call to the correct 51 // base::Bound callback. 52 static void Router(const v8::FunctionCallbackInfo<v8::Value>& args); 53 54 // When RouteFunction is called we create a v8::Object to hold the data we 55 // need when handling it in Router() - this is the base::Bound function to 56 // route to. 57 // 58 // We need a v8::Object because it's possible for v8 to outlive the 59 // base::Bound function; the lifetime of an ObjectBackedNativeHandler is the 60 // lifetime of webkit's involvement with it, not the life of the v8 context. 61 // A scenario when v8 will outlive us is if a frame holds onto the 62 // contentWindow of an iframe after it's removed. 63 // 64 // So, we use v8::Objects here to hold that data, effectively refcounting 65 // the data. When |this| is destroyed we remove the base::Bound function from 66 // the object to indicate that it shoudn't be called. 67 typedef v8::PersistentValueVector<v8::Object> RouterData; 68 RouterData router_data_; 69 70 ScriptContext* context_; 71 72 ScopedPersistent<v8::ObjectTemplate> object_template_; 73 74 DISALLOW_COPY_AND_ASSIGN(ObjectBackedNativeHandler); 75 }; 76 77 } // namespace extensions 78 79 #endif // EXTENSIONS_RENDERER_OBJECT_BACKED_NATIVE_HANDLER_H_ 80
