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