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| 1 // Copyright (c) 2012 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 /* | |
| 6 CppBoundClass class: | |
| 7 This base class serves as a parent for C++ classes designed to be bound to | |
| 8 JavaScript objects. | |
| 9 | |
| 10 Subclasses should define the constructor to build the property and method | |
| 11 lists needed to bind this class to a JS object. They should also declare | |
| 12 and define member variables and methods to be exposed to JS through | |
| 13 that object. | |
| 14 | |
| 15 See cpp_binding_example.{h|cc} for an example. | |
| 16 */ | |
| 17 | |
| 18 #ifndef WEBKIT_RENDERER_CPP_BOUND_CLASS_H_ | |
| 19 #define WEBKIT_RENDERER_CPP_BOUND_CLASS_H_ | |
| 20 | |
| 21 #include <map> | |
| 22 #include <vector> | |
| 23 | |
| 24 #include "base/callback.h" | |
| 25 #include "webkit/renderer/cpp_variant.h" | |
| 26 #include "webkit/renderer/webkit_renderer_export.h" | |
| 27 | |
| 28 namespace WebKit { | |
| 29 class WebFrame; | |
| 30 } | |
| 31 | |
| 32 namespace webkit_glue { | |
| 33 | |
| 34 typedef std::vector<CppVariant> CppArgumentList; | |
| 35 | |
| 36 // CppBoundClass lets you map Javascript method calls and property accesses | |
| 37 // directly to C++ method calls and CppVariant* variable access. | |
| 38 class WEBKIT_RENDERER_EXPORT CppBoundClass { | |
| 39 public: | |
| 40 class PropertyCallback { | |
| 41 public: | |
| 42 virtual ~PropertyCallback() { } | |
| 43 | |
| 44 // Sets |value| to the value of the property. Returns false in case of | |
| 45 // failure. |value| is always non-NULL. | |
| 46 virtual bool GetValue(CppVariant* value) = 0; | |
| 47 | |
| 48 // sets the property value to |value|. Returns false in case of failure. | |
| 49 virtual bool SetValue(const CppVariant& value) = 0; | |
| 50 }; | |
| 51 | |
| 52 // The constructor should call BindCallback, BindProperty, and | |
| 53 // BindFallbackCallback as needed to set up the methods, properties, and | |
| 54 // fallback method. | |
| 55 CppBoundClass(); | |
| 56 virtual ~CppBoundClass(); | |
| 57 | |
| 58 // Return a CppVariant representing this class, for use with BindProperty(). | |
| 59 // The variant type is guaranteed to be NPVariantType_Object. | |
| 60 CppVariant* GetAsCppVariant(); | |
| 61 | |
| 62 // Given a WebFrame, BindToJavascript builds the NPObject that will represent | |
| 63 // this CppBoundClass object and binds it to the frame's window under the | |
| 64 // given name. This should generally be called from the WebView delegate's | |
| 65 // WindowObjectCleared(). This CppBoundClass object will be accessible to | |
| 66 // JavaScript as window.<classname>. The owner of this CppBoundClass object is | |
| 67 // responsible for keeping it around while the frame is alive, and for | |
| 68 // destroying it afterwards. | |
| 69 void BindToJavascript(WebKit::WebFrame* frame, const std::string& classname); | |
| 70 | |
| 71 // The type of callbacks. | |
| 72 typedef base::Callback<void(const CppArgumentList&, CppVariant*)> Callback; | |
| 73 typedef base::Callback<void(CppVariant*)> GetterCallback; | |
| 74 | |
| 75 // Used by a test. Returns true if a method with name |name| exists, | |
| 76 // regardless of whether a fallback is registered. | |
| 77 bool IsMethodRegistered(const std::string& name) const; | |
| 78 | |
| 79 protected: | |
| 80 // Bind the Javascript method called |name| to the C++ callback |callback|. | |
| 81 void BindCallback(const std::string& name, const Callback& callback); | |
| 82 | |
| 83 // Bind Javascript property |name| to the C++ getter callback |callback|. | |
| 84 // This can be used to create read-only properties. | |
| 85 void BindGetterCallback(const std::string& name, | |
| 86 const GetterCallback& callback); | |
| 87 | |
| 88 // Bind the Javascript property called |name| to a CppVariant |prop|. | |
| 89 void BindProperty(const std::string& name, CppVariant* prop); | |
| 90 | |
| 91 // Bind Javascript property called |name| to a PropertyCallback |callback|. | |
| 92 // CppBoundClass assumes control over the life time of the |callback|. | |
| 93 void BindProperty(const std::string& name, PropertyCallback* callback); | |
| 94 | |
| 95 // Set the fallback callback, which is called when when a callback is | |
| 96 // invoked that isn't bound. | |
| 97 // If it is NULL (its default value), a JavaScript exception is thrown in | |
| 98 // that case (as normally expected). If non NULL, the fallback method is | |
| 99 // invoked and the script continues its execution. | |
| 100 // Passing NULL for |callback| clears out any existing binding. | |
| 101 // It is used for tests and should probably only be used in such cases | |
| 102 // as it may cause unexpected behaviors (a JavaScript object with a | |
| 103 // fallback always returns true when checked for a method's | |
| 104 // existence). | |
| 105 void BindFallbackCallback(const Callback& fallback_callback) { | |
| 106 fallback_callback_ = fallback_callback; | |
| 107 } | |
| 108 | |
| 109 // Some fields are protected because some tests depend on accessing them, | |
| 110 // but otherwise they should be considered private. | |
| 111 | |
| 112 typedef std::map<NPIdentifier, PropertyCallback*> PropertyList; | |
| 113 typedef std::map<NPIdentifier, Callback> MethodList; | |
| 114 // These maps associate names with property and method pointers to be | |
| 115 // exposed to JavaScript. | |
| 116 PropertyList properties_; | |
| 117 MethodList methods_; | |
| 118 | |
| 119 // The callback gets invoked when a call is made to an nonexistent method. | |
| 120 Callback fallback_callback_; | |
| 121 | |
| 122 private: | |
| 123 // NPObject callbacks. | |
| 124 friend struct CppNPObject; | |
| 125 bool HasMethod(NPIdentifier ident) const; | |
| 126 bool Invoke(NPIdentifier ident, const NPVariant* args, size_t arg_count, | |
| 127 NPVariant* result); | |
| 128 bool HasProperty(NPIdentifier ident) const; | |
| 129 bool GetProperty(NPIdentifier ident, NPVariant* result) const; | |
| 130 bool SetProperty(NPIdentifier ident, const NPVariant* value); | |
| 131 | |
| 132 // A lazily-initialized CppVariant representing this class. We retain 1 | |
| 133 // reference to this object, and it is released on deletion. | |
| 134 CppVariant self_variant_; | |
| 135 | |
| 136 // TODO(wez): Remove once crrev.com/14019005 lands. | |
| 137 bool bound_to_frame_; | |
| 138 | |
| 139 // Dummy NPP to use to register as owner for NPObjects. | |
| 140 scoped_ptr<NPP_t> npp_; | |
| 141 | |
| 142 DISALLOW_COPY_AND_ASSIGN(CppBoundClass); | |
| 143 }; | |
| 144 | |
| 145 } // namespace webkit_glue | |
| 146 | |
| 147 #endif // WEBKIT_RENDERER_CPP_BOUND_CLASS_H_ | |
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