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/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/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[] = "API is unavailable.";

[not at google - send to devlin, 2013/02/15 22:26:17]

Ok, let's make this nice and informative.

"you do not have permission to access this API. Ensure that the required
permission or manifest property is included in your manifest.json."

[cduvall, 2013/02/19 23:58:49]

Done.

[not at google - send to devlin, 2013/02/20 00:36:38]

Nice, could you make "this API" be %s and use StringPrintf?

[not at google - send to devlin, 2013/02/20 00:49:29]

Never mind, being dumb. Ignore.

 
 #ifndef NDEBUG
 const char kValidateCallbacks[] = "validateCallbacks";
 const char kValidateAPI[] = "validateAPI";
 #endif
 
 }  // namespace
 
 ChromeV8Context::ChromeV8Context(v8::Handle<v8::Context> v8_context,
                                  WebKit::WebFrame* web_frame,
                                  const Extension* extension,
                                  Feature::Context context_type)
     : v8_context_(v8::Persistent<v8::Context>::New(v8_context->GetIsolate(),
                                                    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();
   v8_context_.Dispose(v8_context_->GetIsolate());
 }
 
 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);
 
 #ifndef NDEBUG
-    // 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());
 #endif
   }
 
   DCHECK(hidden->IsObject());
   return v8::Local<v8::Object>::Cast(hidden);
 }
 
 v8::Handle<v8::Value> ChromeV8Context::GetChromeHidden() const {
@@ skipping 50 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();
+
+  if (available_apis.find(api_name) != available_apis.end())

[not at google - send to devlin, 2013/02/15 22:26:17]

Call ExtensionAPI::IsAvailable?

[cduvall, 2013/02/19 23:58:49]

IsAvailable() only works for Features. I added a TODO to switch to that once
Features are ready for all the APIs.

+    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