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 "gin/modules/module_registry_observer.h" 19 #include "v8/include/v8.h" 20 21 namespace extensions { 22 23 class ScriptContext; 24 25 // A module system for JS similar to node.js' require() function. 26 // Each module has three variables in the global scope: 27 // - exports, an object returned to dependencies who require() this 28 // module. 29 // - require, a function that takes a module name as an argument and returns 30 // that module's exports object. 31 // - requireNative, a function that takes the name of a registered 32 // NativeHandler and returns an object that contains the functions the 33 // NativeHandler defines. 34 // 35 // Each module in a ModuleSystem is executed at most once and its exports 36 // object cached. 37 // 38 // Note that a ModuleSystem must be used only in conjunction with a single 39 // v8::Context. 40 // TODO(koz): Rename this to JavaScriptModuleSystem. 41 class ModuleSystem : public ObjectBackedNativeHandler, 42 public gin::ModuleRegistryObserver { 43 public: 44 class SourceMap { 45 public: 46 virtual ~SourceMap() {} 47 virtual v8::Handle<v8::Value> GetSource(v8::Isolate* isolate, 48 const std::string& name) = 0; 49 virtual bool Contains(const std::string& name) = 0; 50 }; 51 52 class ExceptionHandler { 53 public: 54 virtual ~ExceptionHandler() {} 55 virtual void HandleUncaughtException(const v8::TryCatch& try_catch) = 0; 56 57 protected: 58 // Formats |try_catch| as a nice string. 59 std::string CreateExceptionString(const v8::TryCatch& try_catch); 60 }; 61 62 // Enables native bindings for the duration of its lifetime. 63 class NativesEnabledScope { 64 public: 65 explicit NativesEnabledScope(ModuleSystem* module_system); 66 ~NativesEnabledScope(); 67 68 private: 69 ModuleSystem* module_system_; 70 DISALLOW_COPY_AND_ASSIGN(NativesEnabledScope); 71 }; 72 73 // |source_map| is a weak pointer. 74 ModuleSystem(ScriptContext* context, SourceMap* source_map); 75 virtual ~ModuleSystem(); 76 77 // Require the specified module. This is the equivalent of calling 78 // require('module_name') from the loaded JS files. 79 v8::Handle<v8::Value> Require(const std::string& module_name); 80 void Require(const v8::FunctionCallbackInfo<v8::Value>& args); 81 82 // Run |code| in the current context with the name |name| used for stack 83 // traces. 84 v8::Handle<v8::Value> RunString(v8::Handle<v8::String> code, 85 v8::Handle<v8::String> name); 86 87 // Calls the specified method exported by the specified module. This is 88 // equivalent to calling require('module_name').method_name() from JS. 89 v8::Local<v8::Value> CallModuleMethod(const std::string& module_name, 90 const std::string& method_name); 91 v8::Local<v8::Value> CallModuleMethod( 92 const std::string& module_name, 93 const std::string& method_name, 94 std::vector<v8::Handle<v8::Value> >* args); 95 v8::Local<v8::Value> CallModuleMethod(const std::string& module_name, 96 const std::string& method_name, 97 int argc, 98 v8::Handle<v8::Value> argv[]); 99 100 // Register |native_handler| as a potential target for requireNative(), so 101 // calls to requireNative(|name|) from JS will return a new object created by 102 // |native_handler|. 103 void RegisterNativeHandler(const std::string& name, 104 scoped_ptr<NativeHandler> native_handler); 105 106 // Causes requireNative(|name|) to look for its module in |source_map_| 107 // instead of using a registered native handler. This can be used in unit 108 // tests to mock out native modules. 109 void OverrideNativeHandlerForTest(const std::string& name); 110 111 // Executes |code| in the current context with |name| as the filename. 112 void RunString(const std::string& code, const std::string& name); 113 114 // Make |object|.|field| lazily evaluate to the result of 115 // require(|module_name|)[|module_field|]. 116 // 117 // TODO(kalman): All targets for this method are ObjectBackedNativeHandlers, 118 // move this logic into those classes (in fact, the chrome 119 // object is the only client, only that needs to implement it). 120 void SetLazyField(v8::Handle<v8::Object> object, 121 const std::string& field, 122 const std::string& module_name, 123 const std::string& module_field); 124 125 void SetLazyField(v8::Handle<v8::Object> object, 126 const std::string& field, 127 const std::string& module_name, 128 const std::string& module_field, 129 v8::AccessorGetterCallback getter); 130 131 // Make |object|.|field| lazily evaluate to the result of 132 // requireNative(|module_name|)[|module_field|]. 133 // TODO(kalman): Same as above. 134 void SetNativeLazyField(v8::Handle<v8::Object> object, 135 const std::string& field, 136 const std::string& module_name, 137 const std::string& module_field); 138 139 // Passes exceptions to |handler| rather than console::Fatal. 140 void SetExceptionHandlerForTest(scoped_ptr<ExceptionHandler> handler) { 141 exception_handler_ = handler.Pass(); 142 } 143 144 protected: 145 friend class ScriptContext; 146 virtual void Invalidate() OVERRIDE; 147 148 private: 149 typedef std::map<std::string, linked_ptr<NativeHandler> > NativeHandlerMap; 150 151 // Retrieves the lazily defined field specified by |property|. 152 static void LazyFieldGetter(v8::Local<v8::String> property, 153 const v8::PropertyCallbackInfo<v8::Value>& info); 154 // Retrieves the lazily defined field specified by |property| on a native 155 // object. 156 static void NativeLazyFieldGetter( 157 v8::Local<v8::String> property, 158 const v8::PropertyCallbackInfo<v8::Value>& info); 159 160 // Called when an exception is thrown but not caught. 161 void HandleException(const v8::TryCatch& try_catch); 162 163 void RequireForJs(const v8::FunctionCallbackInfo<v8::Value>& args); 164 v8::Local<v8::Value> RequireForJsInner(v8::Handle<v8::String> module_name); 165 166 typedef v8::Handle<v8::Value>(ModuleSystem::*RequireFunction)( 167 const std::string&); 168 // Base implementation of a LazyFieldGetter which uses |require_fn| to require 169 // modules. 170 static void LazyFieldGetterInner( 171 v8::Local<v8::String> property, 172 const v8::PropertyCallbackInfo<v8::Value>& info, 173 RequireFunction require_function); 174 175 // Return the named source file stored in the source map. 176 // |args[0]| - the name of a source file in source_map_. 177 v8::Handle<v8::Value> GetSource(const std::string& module_name); 178 179 // Return an object that contains the native methods defined by the named 180 // NativeHandler. 181 // |args[0]| - the name of a native handler object. 182 v8::Handle<v8::Value> RequireNativeFromString(const std::string& native_name); 183 void RequireNative(const v8::FunctionCallbackInfo<v8::Value>& args); 184 185 // Return a promise for a requested module. 186 // |args[0]| - the name of a module. 187 void RequireAsync(const v8::FunctionCallbackInfo<v8::Value>& args); 188 189 // Wraps |source| in a (function(define, require, requireNative, ...) {...}). 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 // Loads and runs a Javascript module. 196 v8::Handle<v8::Value> LoadModule(const std::string& module_name); 197 198 // Invoked when a module is loaded in response to a requireAsync call. 199 // Resolves |resolver| with |value|. 200 void OnModuleLoaded( 201 scoped_ptr<v8::UniquePersistent<v8::Promise::Resolver> > resolver, 202 v8::Handle<v8::Value> value); 203 204 // gin::ModuleRegistryObserver overrides. 205 virtual void OnDidAddPendingModule( 206 const std::string& id, 207 const std::vector<std::string>& dependencies) OVERRIDE; 208 209 ScriptContext* context_; 210 211 // A map from module names to the JS source for that module. GetSource() 212 // performs a lookup on this map. 213 SourceMap* source_map_; 214 215 // A map from native handler names to native handlers. 216 NativeHandlerMap native_handler_map_; 217 218 // When 0, natives are disabled, otherwise indicates how many callers have 219 // pinned natives as enabled. 220 int natives_enabled_; 221 222 // Called when an exception is thrown but not caught in JS. Overridable by 223 // tests. 224 scoped_ptr<ExceptionHandler> exception_handler_; 225 226 std::set<std::string> overridden_native_handlers_; 227 228 base::WeakPtrFactory<ModuleSystem> weak_factory_; 229 230 DISALLOW_COPY_AND_ASSIGN(ModuleSystem); 231 }; 232 233 } // namespace extensions 234 235 #endif // EXTENSIONS_RENDERER_MODULE_SYSTEM_H_ 236
