Implement a module system for the extension bindings JS.

chrome/renderer/module_system_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/string_piece.h"
 #include "chrome/renderer/module_system.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 #include <map>
 #include <string>
 
+// Native JS functions for doing asserts.
 class AssertNatives : public NativeHandler {
  public:
   AssertNatives()
       : native_function_called_(false),
         failed_(false) {
     RouteFunction("AssertTrue", base::Bind(&AssertNatives::AssertTrue,
         base::Unretained(this)));
   }
 
   bool native_function_called() { return native_function_called_; }
   bool failed() { return failed_; }
 
   v8::Handle<v8::Value> AssertTrue(const v8::Arguments& args) {
     native_function_called_ = true;
     failed_ = failed_ || !args[0]->ToBoolean()->Value();
     return v8::Undefined();
   }
 
  private:
   bool native_function_called_;
   bool failed_;
 };
 
+class StringSourceMap : public ModuleSystem::SourceMap {
+ public:
+  StringSourceMap() {}
+
+  v8::Handle<v8::Value> GetSource(const std::string& name) OVERRIDE {
+    if (source_map_.count(name) == 0)
+      return v8::Undefined();
+    return v8::String::New(source_map_[name].c_str());
+  }
+
+  bool Contains(const std::string& name) OVERRIDE {
+    return source_map_.count(name);
+  }
+
+  void RegisterModule(const std::string& name, const std::string& source) {
+    source_map_[name] = source;
+  }
+
+ private:
+  std::map<std::string, std::string> source_map_;
+};
+
+// Native JS functions for disabling injection in ModuleSystem.
+class DisableNativesHandler : public NativeHandler {
+ public:
+  explicit DisableNativesHandler(ModuleSystem* module_system)
+      : module_system_(module_system) {
+    RouteFunction("DisableNatives",
+                  base::Bind(&DisableNativesHandler::DisableNatives,
+                             base::Unretained(this)));
+  }
+
+  v8::Handle<v8::Value> DisableNatives(const v8::Arguments& args) {
+    module_system_->set_natives_enabled(false);
+    return v8::Undefined();
+  }
+
+ private:
+  ModuleSystem* module_system_;
+};
+
 class ModuleSystemTest : public testing::Test {
  public:
   ModuleSystemTest()
       : context_(v8::Context::New()),
-        assert_natives_(new AssertNatives()) {
+        handle_scope_(),
+        source_map_(new StringSourceMap()) {
     context_->Enter();
-    source_map_["add"] = "exports.Add = function(x, y) { return x + y; };";
-    module_system_.reset(new ModuleSystem(&source_map_));
+    assert_natives_ = new AssertNatives();
+    module_system_.reset(new ModuleSystem(source_map_));
     module_system_->RegisterNativeHandler("assert", scoped_ptr<NativeHandler>(
         assert_natives_));
+    RegisterModule("add", "exports.Add = function(x, y) { return x + y; };");
   }
 
   ~ModuleSystemTest() {
+    context_->Exit();
     context_.Dispose();
   }
 
+  void RegisterModule(const std::string& name, const std::string& code) {
+    source_map_->RegisterModule(name, code);
+  }
+
   virtual void TearDown() {
     // All tests must call a native function at least once.
     ASSERT_TRUE(assert_natives_->native_function_called());
     ASSERT_FALSE(assert_natives_->failed());
     ASSERT_FALSE(try_catch_.HasCaught());
   }
 
+  v8::Persistent<v8::Context> context_;
   v8::HandleScope handle_scope_;
   v8::TryCatch try_catch_;
-  v8::Persistent<v8::Context> context_;
   AssertNatives* assert_natives_;
-  std::map<std::string, std::string> source_map_;
+  StringSourceMap* source_map_;
   scoped_ptr<ModuleSystem> module_system_;
 };
 
 TEST_F(ModuleSystemTest, TestRequire) {
-  source_map_["test"] =
+  RegisterModule("test",
       "var Add = require('add').Add;"
-      "requireNative('assert').AssertTrue(Add(3, 5) == 8);";
+      "requireNative('assert').AssertTrue(Add(3, 5) == 8);");
   module_system_->Require("test");
 }
 
 TEST_F(ModuleSystemTest, TestNestedRequire) {
-  source_map_["double"] =
+  RegisterModule("double",
       "var Add = require('add').Add;"
-      "exports.Double = function(x) { return Add(x, x); };";
-  source_map_["test"] =
+      "exports.Double = function(x) { return Add(x, x); };");
+  RegisterModule("test",
       "var Double = require('double').Double;"
-      "requireNative('assert').AssertTrue(Double(3) == 6);";
+      "requireNative('assert').AssertTrue(Double(3) == 6);");
   module_system_->Require("test");
 }
 
 TEST_F(ModuleSystemTest, TestModuleInsulation) {
-  source_map_["x"] =
+  RegisterModule("x",
       "var x = 10;"
-      "exports.X = function() { return x; };";
-  source_map_["y"] =
+      "exports.X = function() { return x; };");
+  RegisterModule("y",
       "var x = 15;"
       "require('x');"
-      "exports.Y = function() { return x; };";
-  source_map_["test"] =
+      "exports.Y = function() { return x; };");
+  RegisterModule("test",
       "var Y = require('y').Y;"
       "var X = require('x').X;"
       "var assert = requireNative('assert');"
       "assert.AssertTrue(!this.hasOwnProperty('x'));"
       "assert.AssertTrue(Y() == 15);"
-      "assert.AssertTrue(X() == 10);";
+      "assert.AssertTrue(X() == 10);");
   module_system_->Require("test");
 }
+
+TEST_F(ModuleSystemTest, TestDisableNativesPreventsNativeModulesBeingLoaded) {
+  module_system_->RegisterNativeHandler("disable",
+      scoped_ptr<NativeHandler>(
+          new DisableNativesHandler(module_system_.get())));
+  RegisterModule("test",
+      "var assert = requireNative('assert');"
+      "var disable = requireNative('disable');"
+      "disable.DisableNatives();"
+      "var caught = false;"
+      "try {"
+      "  requireNative('assert');"
+      "} catch (e) {"
+      "  caught = true;"
+      "}"
+      "assert.AssertTrue(caught);");
+  module_system_->Require("test");
+}