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_MODULE_SYSTEM_H_ 6 #define EXTENSIONS_RENDERER_MODULE_SYSTEM_H_ 7 8 #include <map> 9 #include <set> 10 #include <string> 11 #include <vector> 12 13 #include "base/compiler_specific.h" 14 #include "base/memory/linked_ptr.h" 15 #include "base/memory/scoped_ptr.h" 16 #include "extensions/renderer/native_handler.h" 17 #include "extensions/renderer/object_backed_native_handler.h" 18 #include "v8/include/v8.h" 19 20 namespace extensions { 21 22 class ScriptContext; 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: ~SourceMap()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: ~ExceptionHandler()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(ScriptContext* 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 // Run |code| in the current context with the name |name| used for stack 81 // traces. 82 v8::Handle<v8::Value> RunString(v8::Handle<v8::String> code, 83 v8::Handle<v8::String> name); 84 85 // Calls the specified method exported by the specified module. This is 86 // equivalent to calling require('module_name').method_name() from JS. 87 v8::Local<v8::Value> CallModuleMethod(const std::string& module_name, 88 const std::string& method_name); 89 v8::Local<v8::Value> CallModuleMethod( 90 const std::string& module_name, 91 const std::string& method_name, 92 std::vector<v8::Handle<v8::Value> >* args); 93 v8::Local<v8::Value> CallModuleMethod(const std::string& module_name, 94 const std::string& method_name, 95 int argc, 96 v8::Handle<v8::Value> argv[]); 97 98 // Register |native_handler| as a potential target for requireNative(), so 99 // calls to requireNative(|name|) from JS will return a new object created by 100 // |native_handler|. 101 void RegisterNativeHandler(const std::string& name, 102 scoped_ptr<NativeHandler> native_handler); 103 104 // Causes requireNative(|name|) to look for its module in |source_map_| 105 // instead of using a registered native handler. This can be used in unit 106 // tests to mock out native modules. 107 void OverrideNativeHandlerForTest(const std::string& name); 108 109 // Executes |code| in the current context with |name| as the filename. 110 void RunString(const std::string& code, const std::string& name); 111 112 // Make |object|.|field| lazily evaluate to the result of 113 // require(|module_name|)[|module_field|]. 114 // 115 // TODO(kalman): All targets for this method are ObjectBackedNativeHandlers, 116 // move this logic into those classes (in fact, the chrome 117 // object is the only client, only that needs to implement it). 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); 122 123 void SetLazyField(v8::Handle<v8::Object> object, 124 const std::string& field, 125 const std::string& module_name, 126 const std::string& module_field, 127 v8::AccessorGetterCallback getter); 128 129 // Make |object|.|field| lazily evaluate to the result of 130 // requireNative(|module_name|)[|module_field|]. 131 // TODO(kalman): Same as above. 132 void SetNativeLazyField(v8::Handle<v8::Object> object, 133 const std::string& field, 134 const std::string& module_name, 135 const std::string& module_field); 136 137 // Passes exceptions to |handler| rather than console::Fatal. SetExceptionHandlerForTest(scoped_ptr<ExceptionHandler> handler)138 void SetExceptionHandlerForTest(scoped_ptr<ExceptionHandler> handler) { 139 exception_handler_ = handler.Pass(); 140 } 141 142 protected: 143 friend class ScriptContext; 144 virtual void Invalidate() OVERRIDE; 145 146 private: 147 typedef std::map<std::string, linked_ptr<NativeHandler> > NativeHandlerMap; 148 149 // Retrieves the lazily defined field specified by |property|. 150 static void LazyFieldGetter(v8::Local<v8::String> property, 151 const v8::PropertyCallbackInfo<v8::Value>& info); 152 // Retrieves the lazily defined field specified by |property| on a native 153 // object. 154 static void NativeLazyFieldGetter( 155 v8::Local<v8::String> property, 156 const v8::PropertyCallbackInfo<v8::Value>& info); 157 158 // Called when an exception is thrown but not caught. 159 void HandleException(const v8::TryCatch& try_catch); 160 161 // Ensure that require_ has been evaluated from require.js. 162 void EnsureRequireLoaded(); 163 164 void RequireForJs(const v8::FunctionCallbackInfo<v8::Value>& args); 165 v8::Local<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 // NativeHandler implementation which returns the private area of an Object. 190 void Private(const v8::FunctionCallbackInfo<v8::Value>& args); 191 192 // NativeHandler implementation which returns a function wrapper for a 193 // provided function. 194 void CreateFunctionWrapper(const v8::FunctionCallbackInfo<v8::Value>& args); 195 196 ScriptContext* context_; 197 198 // A map from module names to the JS source for that module. GetSource() 199 // performs a lookup on this map. 200 SourceMap* source_map_; 201 202 // A map from native handler names to native handlers. 203 NativeHandlerMap native_handler_map_; 204 205 // When 0, natives are disabled, otherwise indicates how many callers have 206 // pinned natives as enabled. 207 int natives_enabled_; 208 209 // Called when an exception is thrown but not caught in JS. Overridable by 210 // tests. 211 scoped_ptr<ExceptionHandler> exception_handler_; 212 213 std::set<std::string> overridden_native_handlers_; 214 215 DISALLOW_COPY_AND_ASSIGN(ModuleSystem); 216 }; 217 218 } // namespace extensions 219 220 #endif // EXTENSIONS_RENDERER_MODULE_SYSTEM_H_ 221