Lazy load chrome.* APIs

chrome/renderer/extensions/chrome_v8_context.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 "chrome/renderer/extensions/chrome_v8_context.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/strings/string_split.h"
 #include "base/values.h"
 #include "chrome/common/extensions/api/extension_api.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_set.h"
 #include "chrome/renderer/extensions/chrome_v8_extension.h"
+#include "chrome/renderer/extensions/module_system.h"
 #include "chrome/renderer/extensions/user_script_slave.h"
 #include "content/public/renderer/render_view.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebFrame.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
 #include "v8/include/v8.h"
 
 namespace extensions {
 
 namespace {
 
 const char kChromeHidden[] = "chromeHidden";
+const char kUnavailableMessage[] = "You do not have permission to access this "
+                                   "API. Ensure that the required permission "
+                                   "or manifest property is included in your "
+                                   "manifest.json.";
 
 const char kValidateCallbacks[] = "validateCallbacks";
 const char kValidateAPI[] = "validateAPI";
 
 }  // namespace
 
 ChromeV8Context::ChromeV8Context(v8::Handle<v8::Context> v8_context,
                                  WebKit::WebFrame* web_frame,
                                  const Extension* extension,
                                  Feature::Context context_type)
     : v8_context_(v8_context),
       web_frame_(web_frame),
       extension_(extension),
-      context_type_(context_type) {
+      context_type_(context_type),
+      available_extension_apis_initialized_(false) {
   VLOG(1) << "Created context:\n"
           << "  extension id: " << GetExtensionID() << "\n"
           << "  frame:        " << web_frame_ << "\n"
           << "  context type: " << GetContextTypeDescription();
 }
 
 ChromeV8Context::~ChromeV8Context() {
   VLOG(1) << "Destroyed context for extension\n"
           << "  extension id: " << GetExtensionID();
+  Invalidate();
+}
+
+void ChromeV8Context::Invalidate() {
+  if (v8_context_.get().IsEmpty())
+    return;
+  if (module_system_)
+    module_system_->Invalidate();
+  web_frame_ = NULL;
+  v8_context_.reset();
 }
 
 std::string ChromeV8Context::GetExtensionID() {
   return extension_ ? extension_->id() : "";
 }
 
 // static
 v8::Handle<v8::Value> ChromeV8Context::GetOrCreateChromeHidden(
     v8::Handle<v8::Context> context) {
   v8::Local<v8::Object> global = context->Global();
   v8::Local<v8::Value> hidden = global->GetHiddenValue(
       v8::String::New(kChromeHidden));
 
   if (hidden.IsEmpty() || hidden->IsUndefined()) {
     hidden = v8::Object::New();
     global->SetHiddenValue(v8::String::New(kChromeHidden), hidden);
 
     if (DCHECK_IS_ON()) {
-      // Tell schema_generated_bindings.js to validate callbacks and events
-      // against their schema definitions.
+      // Tell bindings.js to validate callbacks and events against their schema
+      // definitions.
       v8::Local<v8::Object>::Cast(hidden)->Set(
           v8::String::New(kValidateCallbacks), v8::True());
-      // Tell schema_generated_bindings.js to validate API for ambiguity.
+      // Tell bindings.js to validate API for ambiguity.
       v8::Local<v8::Object>::Cast(hidden)->Set(
           v8::String::New(kValidateAPI), v8::True());
     }
   }
 
   DCHECK(hidden->IsObject());
   return v8::Local<v8::Object>::Cast(hidden);
 }
 
 v8::Handle<v8::Value> ChromeV8Context::GetChromeHidden() const {
   v8::Local<v8::Object> global = v8_context_->Global();
   return global->GetHiddenValue(v8::String::New(kChromeHidden));
 }
 
 content::RenderView* ChromeV8Context::GetRenderView() const {
   if (web_frame_ && web_frame_->view())
     return content::RenderView::FromWebView(web_frame_->view());
   else
     return NULL;
 }
 
 bool ChromeV8Context::CallChromeHiddenMethod(
     const std::string& function_name,
     int argc,
     v8::Handle<v8::Value>* argv,
     v8::Handle<v8::Value>* result) const {
   v8::Context::Scope context_scope(v8_context_.get());
 
-  // ChromeV8ContextSet calls clear_web_frame() and then schedules a task to
-  // delete this object. This check prevents a race from attempting to execute
-  // script on a NULL web_frame_.
+  // ChromeV8ContextSet calls Invalidate() and then schedules a task to delete
+  // this object. This check prevents a race from attempting to execute script
+  // on a NULL web_frame_.
   if (!web_frame_)
     return false;
 
   // Look up the function name, which may be a sub-property like
   // "Port.dispatchOnMessage" in the hidden global variable.
   v8::Local<v8::Value> value = v8::Local<v8::Value>::New(GetChromeHidden());
   if (value.IsEmpty())
     return false;
 
   std::vector<std::string> components;
@@ skipping 19 matching lines @@
                                                    v8::Object::New(),
                                                    argc,
                                                    argv);
   if (result)
     *result = result_temp;
 
   return true;
 }
 
 const std::set<std::string>& ChromeV8Context::GetAvailableExtensionAPIs() {
-  if (!available_extension_apis_.get()) {
+  if (!available_extension_apis_initialized_) {
     available_extension_apis_ =
         ExtensionAPI::GetSharedInstance()->GetAPIsForContext(
             context_type_,
             extension_,
-            UserScriptSlave::GetDataSourceURLForFrame(
-                web_frame_)).Pass();
+            UserScriptSlave::GetDataSourceURLForFrame(web_frame_));
+    available_extension_apis_initialized_ = true;
   }
-  return *(available_extension_apis_.get());
+  return available_extension_apis_;
+}
+
+Feature::Availability ChromeV8Context::GetAvailability(
+    const std::string& api_name) {
+  const std::set<std::string>& available_apis = GetAvailableExtensionAPIs();
+
+  // TODO(cduvall/kalman): Switch to ExtensionAPI::IsAvailable() once Features
+  // are complete.
+  if (available_apis.find(api_name) != available_apis.end())
+    return Feature::CreateAvailability(Feature::IS_AVAILABLE, "");
+
+  return Feature::CreateAvailability(Feature::INVALID_CONTEXT,
+                                     kUnavailableMessage);
 }
 
 void ChromeV8Context::DispatchOnLoadEvent(bool is_incognito_process,
                                           int manifest_version) {
   v8::HandleScope handle_scope;
   v8::Handle<v8::Value> argv[] = {
     v8::String::New(GetExtensionID().c_str()),
     v8::String::New(GetContextTypeDescription().c_str()),
     v8::Boolean::New(is_incognito_process),
     v8::Integer::New(manifest_version),
@@ skipping 12 matching lines @@
     case Feature::BLESSED_EXTENSION_CONTEXT:   return "BLESSED_EXTENSION";
     case Feature::UNBLESSED_EXTENSION_CONTEXT: return "UNBLESSED_EXTENSION";
     case Feature::CONTENT_SCRIPT_CONTEXT:      return "CONTENT_SCRIPT";
     case Feature::WEB_PAGE_CONTEXT:            return "WEB_PAGE";
   }
   NOTREACHED();
   return "";
 }
 
 }  // namespace extensions