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 #ifndef CHROME_RENDERER_EXTENSIONS_MODULE_SYSTEM_H_ 6 #define CHROME_RENDERER_EXTENSIONS_MODULE_SYSTEM_H_ 7 8 #include "base/compiler_specific.h" 9 #include "base/memory/linked_ptr.h" 10 #include "base/memory/scoped_ptr.h" 11 #include "chrome/renderer/extensions/native_handler.h" 12 #include "chrome/renderer/extensions/object_backed_native_handler.h" 13 #include "v8/include/v8.h" 14 15 #include <map> 16 #include <set> 17 #include <string> 18 #include <vector> 19 20 namespace extensions { 21 22 class ChromeV8Context; 23 24 // A module system for JS similar to node.js' require() function. 25 // Each module has three variables in the global scope: 26 // - exports, an object returned to dependencies who require() this 27 // module. 28 // - require, a function that takes a module name as an argument and returns 29 // that module's exports object. 30 // - requireNative, a function that takes the name of a registered 31 // NativeHandler and returns an object that contains the functions the 32 // NativeHandler defines. 33 // 34 // Each module in a ModuleSystem is executed at most once and its exports 35 // object cached. 36 // 37 // Note that a ModuleSystem must be used only in conjunction with a single 38 // v8::Context. 39 // TODO(koz): Rename this to JavaScriptModuleSystem. 40 class ModuleSystem : public ObjectBackedNativeHandler { 41 public: 42 class SourceMap { 43 public: 44 virtual ~SourceMap() {} 45 virtual v8::Handle<v8::Value> GetSource(v8::Isolate* isolate, 46 const std::string& name) = 0; 47 virtual bool Contains(const std::string& name) = 0; 48 }; 49 50 class ExceptionHandler { 51 public: 52 virtual ~ExceptionHandler() {} 53 virtual void HandleUncaughtException(const v8::TryCatch& try_catch) = 0; 54 55 protected: 56 // Formats |try_catch| as a nice string. 57 std::string CreateExceptionString(const v8::TryCatch& try_catch); 58 }; 59 60 // Enables native bindings for the duration of its lifetime. 61 class NativesEnabledScope { 62 public: 63 explicit NativesEnabledScope(ModuleSystem* module_system); 64 ~NativesEnabledScope(); 65 66 private: 67 ModuleSystem* module_system_; 68 DISALLOW_COPY_AND_ASSIGN(NativesEnabledScope); 69 }; 70 71 // |source_map| is a weak pointer. 72 ModuleSystem(ChromeV8Context* context, SourceMap* source_map); 73 virtual ~ModuleSystem(); 74 75 // Require the specified module. This is the equivalent of calling 76 // require('module_name') from the loaded JS files. 77 v8::Handle<v8::Value> Require(const std::string& module_name); 78 void Require(const v8::FunctionCallbackInfo<v8::Value>& args); 79 80 // Calls the specified method exported by the specified module. This is 81 // equivalent to calling require('module_name').method_name() from JS. 82 v8::Local<v8::Value> CallModuleMethod(const std::string& module_name, 83 const std::string& method_name); 84 v8::Local<v8::Value> CallModuleMethod( 85 const std::string& module_name, 86 const std::string& method_name, 87 std::vector<v8::Handle<v8::Value> >* args); 88 v8::Local<v8::Value> CallModuleMethod( 89 const std::string& module_name, 90 const std::string& method_name, 91 int argc, 92 v8::Handle<v8::Value> argv[]); 93 94 // Register |native_handler| as a potential target for requireNative(), so 95 // calls to requireNative(|name|) from JS will return a new object created by 96 // |native_handler|. 97 void RegisterNativeHandler(const std::string& name, 98 scoped_ptr<NativeHandler> native_handler); 99 100 // Causes requireNative(|name|) to look for its module in |source_map_| 101 // instead of using a registered native handler. This can be used in unit 102 // tests to mock out native modules. 103 void OverrideNativeHandlerForTest(const std::string& name); 104 105 // Executes |code| in the current context with |name| as the filename. 106 void RunString(const std::string& code, const std::string& name); 107 108 // Make |object|.|field| lazily evaluate to the result of 109 // require(|module_name|)[|module_field|]. 110 // 111 // TODO(kalman): All targets for this method are ObjectBackedNativeHandlers, 112 // move this logic into those classes (in fact, the chrome 113 // object is the only client, only that needs to implement it). 114 void SetLazyField(v8::Handle<v8::Object> object, 115 const std::string& field, 116 const std::string& module_name, 117 const std::string& module_field); 118 119 void SetLazyField(v8::Handle<v8::Object> object, 120 const std::string& field, 121 const std::string& module_name, 122 const std::string& module_field, 123 v8::AccessorGetterCallback getter); 124 125 // Make |object|.|field| lazily evaluate to the result of 126 // requireNative(|module_name|)[|module_field|]. 127 // TODO(kalman): Same as above. 128 void SetNativeLazyField(v8::Handle<v8::Object> object, 129 const std::string& field, 130 const std::string& module_name, 131 const std::string& module_field); 132 133 // Passes exceptions to |handler| rather than console::Fatal. 134 void SetExceptionHandlerForTest(scoped_ptr<ExceptionHandler> handler) { 135 exception_handler_ = handler.Pass(); 136 } 137 138 v8::Isolate* GetIsolate() const; 139 140 protected: 141 friend class ChromeV8Context; 142 virtual void Invalidate() OVERRIDE; 143 144 private: 145 typedef std::map<std::string, linked_ptr<NativeHandler> > NativeHandlerMap; 146 147 // Retrieves the lazily defined field specified by |property|. 148 static void LazyFieldGetter(v8::Local<v8::String> property, 149 const v8::PropertyCallbackInfo<v8::Value>& info); 150 // Retrieves the lazily defined field specified by |property| on a native 151 // object. 152 static void NativeLazyFieldGetter( 153 v8::Local<v8::String> property, 154 const v8::PropertyCallbackInfo<v8::Value>& info); 155 156 // Called when an exception is thrown but not caught. 157 void HandleException(const v8::TryCatch& try_catch); 158 159 // Ensure that require_ has been evaluated from require.js. 160 void EnsureRequireLoaded(); 161 162 // Run |code| in the current context with the name |name| used for stack 163 // traces. 164 v8::Handle<v8::Value> RunString(v8::Handle<v8::String> code, 165 v8::Handle<v8::String> name); 166 167 void RequireForJs(const v8::FunctionCallbackInfo<v8::Value>& args); 168 v8::Local<v8::Value> RequireForJsInner(v8::Handle<v8::String> module_name); 169 170 typedef v8::Handle<v8::Value> (ModuleSystem::*RequireFunction)( 171 const std::string&); 172 // Base implementation of a LazyFieldGetter which uses |require_fn| to require 173 // modules. 174 static void LazyFieldGetterInner( 175 v8::Local<v8::String> property, 176 const v8::PropertyCallbackInfo<v8::Value>& info, 177 RequireFunction require_function); 178 179 // Return the named source file stored in the source map. 180 // |args[0]| - the name of a source file in source_map_. 181 v8::Handle<v8::Value> GetSource(const std::string& module_name); 182 183 // Return an object that contains the native methods defined by the named 184 // NativeHandler. 185 // |args[0]| - the name of a native handler object. 186 v8::Handle<v8::Value> RequireNativeFromString(const std::string& native_name); 187 void RequireNative(const v8::FunctionCallbackInfo<v8::Value>& args); 188 189 // Wraps |source| in a (function(require, requireNative, exports) {...}). 190 v8::Handle<v8::String> WrapSource(v8::Handle<v8::String> source); 191 192 // NativeHandler implementation which returns the private area of an Object. 193 void Private(const v8::FunctionCallbackInfo<v8::Value>& args); 194 195 ChromeV8Context* context_; 196 197 // A map from module names to the JS source for that module. GetSource() 198 // performs a lookup on this map. 199 SourceMap* source_map_; 200 201 // A map from native handler names to native handlers. 202 NativeHandlerMap native_handler_map_; 203 204 // When 0, natives are disabled, otherwise indicates how many callers have 205 // pinned natives as enabled. 206 int natives_enabled_; 207 208 // Called when an exception is thrown but not caught in JS. Overridable by 209 // tests. 210 scoped_ptr<ExceptionHandler> exception_handler_; 211 212 std::set<std::string> overridden_native_handlers_; 213 214 DISALLOW_COPY_AND_ASSIGN(ModuleSystem); 215 }; 216 217 } // namespace extensions 218 219 #endif // CHROME_RENDERER_EXTENSIONS_MODULE_SYSTEM_H_ 220
