content/renderer/pepper/message_channel.cc

   1 // Copyright (c) 2012 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 #include "content/renderer/pepper/message_channel.h"
   6
   7 #include <cstdlib>
   8 #include <string>
   9
  10 #include "base/bind.h"
  11 #include "base/logging.h"
  12 #include "base/message_loop/message_loop.h"
  13 #include "content/renderer/pepper/host_array_buffer_var.h"
  14 #include "content/renderer/pepper/pepper_plugin_instance_impl.h"
  15 #include "content/renderer/pepper/pepper_try_catch.h"
  16 #include "content/renderer/pepper/plugin_module.h"
  17 #include "content/renderer/pepper/plugin_object.h"
  18 #include "gin/arguments.h"
  19 #include "gin/converter.h"
  20 #include "gin/function_template.h"
  21 #include "gin/object_template_builder.h"
  22 #include "gin/public/gin_embedders.h"
  23 #include "ppapi/shared_impl/ppapi_globals.h"
  24 #include "ppapi/shared_impl/scoped_pp_var.h"
  25 #include "ppapi/shared_impl/var.h"
  26 #include "ppapi/shared_impl/var_tracker.h"
  27 #include "third_party/WebKit/public/web/WebBindings.h"
  28 #include "third_party/WebKit/public/web/WebDocument.h"
  29 #include "third_party/WebKit/public/web/WebDOMMessageEvent.h"
  30 #include "third_party/WebKit/public/web/WebElement.h"
  31 #include "third_party/WebKit/public/web/WebLocalFrame.h"
  32 #include "third_party/WebKit/public/web/WebNode.h"
  33 #include "third_party/WebKit/public/web/WebPluginContainer.h"
  34 #include "third_party/WebKit/public/web/WebSerializedScriptValue.h"
  35 #include "v8/include/v8.h"
  36
  37 using ppapi::ArrayBufferVar;
  38 using ppapi::PpapiGlobals;
  39 using ppapi::ScopedPPVar;
  40 using ppapi::StringVar;
  41 using blink::WebBindings;
  42 using blink::WebElement;
  43 using blink::WebDOMEvent;
  44 using blink::WebDOMMessageEvent;
  45 using blink::WebPluginContainer;
  46 using blink::WebSerializedScriptValue;
  47
  48 namespace content {
  49
  50 namespace {
  51
  52 const char kPostMessage[] = "postMessage";
  53 const char kPostMessageAndAwaitResponse[] = "postMessageAndAwaitResponse";
  54 const char kV8ToVarConversionError[] =
  55     "Failed to convert a PostMessage "
  56     "argument from a JavaScript value to a PP_Var. It may have cycles or be of "
  57     "an unsupported type.";
  58 const char kVarToV8ConversionError[] =
  59     "Failed to convert a PostMessage "
  60     "argument from a PP_Var to a Javascript value. It may have cycles or be of "
  61     "an unsupported type.";
  62
  63 }  // namespace
  64
  65 // MessageChannel --------------------------------------------------------------
  66 struct MessageChannel::VarConversionResult {
  67   VarConversionResult() : success_(false), conversion_completed_(false) {}
  68   void ConversionCompleted(const ScopedPPVar& var,
  69                            bool success) {
  70     conversion_completed_ = true;
  71     var_ = var;
  72     success_ = success;
  73   }
  74   const ScopedPPVar& var() const { return var_; }
  75   bool success() const { return success_; }
  76   bool conversion_completed() const { return conversion_completed_; }
  77
  78  private:
  79   ScopedPPVar var_;
  80   bool success_;
  81   bool conversion_completed_;
  82 };
  83
  84 // static
  85 gin::WrapperInfo MessageChannel::kWrapperInfo = {gin::kEmbedderNativeGin};
  86
  87 // static
  88 MessageChannel* MessageChannel::Create(PepperPluginInstanceImpl* instance,
  89                                        v8::Persistent<v8::Object>* result) {
  90   MessageChannel* message_channel = new MessageChannel(instance);
  91   v8::HandleScope handle_scope(instance->GetIsolate());
  92   v8::Context::Scope context_scope(instance->GetMainWorldContext());
  93   gin::Handle<MessageChannel> handle =
  94       gin::CreateHandle(instance->GetIsolate(), message_channel);
  95   result->Reset(instance->GetIsolate(), handle.ToV8()->ToObject());
  96   return message_channel;
  97 }
  98
  99 MessageChannel::~MessageChannel() {
 100   UnregisterSyncMessageStatusObserver();
 101
 102   passthrough_object_.Reset();
 103   if (instance_)
 104     instance_->MessageChannelDestroyed();
 105 }
 106
 107 void MessageChannel::InstanceDeleted() {
 108   UnregisterSyncMessageStatusObserver();
 109   instance_ = NULL;
 110 }
 111
 112 void MessageChannel::PostMessageToJavaScript(PP_Var message_data) {
 113   v8::HandleScope scope(v8::Isolate::GetCurrent());
 114
 115   // Because V8 is probably not on the stack for Native->JS calls, we need to
 116   // enter the appropriate context for the plugin.
 117   v8::Local<v8::Context> context = instance_->GetMainWorldContext();
 118   if (context.IsEmpty())
 119     return;
 120
 121   v8::Context::Scope context_scope(context);
 122
 123   v8::Handle<v8::Value> v8_val;
 124   if (!var_converter_.ToV8Value(message_data, context, &v8_val)) {
 125     PpapiGlobals::Get()->LogWithSource(instance_->pp_instance(),
 126                                        PP_LOGLEVEL_ERROR,
 127                                        std::string(),
 128                                        kVarToV8ConversionError);
 129     return;
 130   }
 131
 132   WebSerializedScriptValue serialized_val =
 133       WebSerializedScriptValue::serialize(v8_val);
 134
 135   if (js_message_queue_state_ != SEND_DIRECTLY) {
 136     // We can't just PostTask here; the messages would arrive out of
 137     // order. Instead, we queue them up until we're ready to post
 138     // them.
 139     js_message_queue_.push_back(serialized_val);
 140   } else {
 141     // The proxy sent an asynchronous message, so the plugin is already
 142     // unblocked. Therefore, there's no need to PostTask.
 143     DCHECK(js_message_queue_.empty());
 144     PostMessageToJavaScriptImpl(serialized_val);
 145   }
 146 }
 147
 148 void MessageChannel::Start() {
 149   DCHECK_EQ(WAITING_TO_START, js_message_queue_state_);
 150   DCHECK_EQ(WAITING_TO_START, plugin_message_queue_state_);
 151
 152   ppapi::proxy::HostDispatcher* dispatcher =
 153       ppapi::proxy::HostDispatcher::GetForInstance(instance_->pp_instance());
 154   // The dispatcher is NULL for in-process.
 155   if (dispatcher) {
 156     unregister_observer_callback_ =
 157         dispatcher->AddSyncMessageStatusObserver(this);
 158   }
 159
 160   // We can't drain the JS message queue directly since we haven't finished
 161   // initializing the PepperWebPluginImpl yet, so the plugin isn't available in
 162   // the DOM.
 163   DrainJSMessageQueueSoon();
 164
 165   plugin_message_queue_state_ = SEND_DIRECTLY;
 166   DrainCompletedPluginMessages();
 167 }
 168
 169 void MessageChannel::SetPassthroughObject(v8::Handle<v8::Object> passthrough) {
 170   passthrough_object_.Reset(instance_->GetIsolate(), passthrough);
 171 }
 172
 173 void MessageChannel::SetReadOnlyProperty(PP_Var key, PP_Var value) {
 174   StringVar* key_string = StringVar::FromPPVar(key);
 175   if (key_string) {
 176     internal_named_properties_[key_string->value()] = ScopedPPVar(value);
 177   } else {
 178     NOTREACHED();
 179   }
 180 }
 181
 182 MessageChannel::MessageChannel(PepperPluginInstanceImpl* instance)
 183     : gin::NamedPropertyInterceptor(instance->GetIsolate(), this),
 184       instance_(instance),
 185       js_message_queue_state_(WAITING_TO_START),
 186       blocking_message_depth_(0),
 187       plugin_message_queue_state_(WAITING_TO_START),
 188       var_converter_(instance->pp_instance(),
 189                      V8VarConverter::kDisallowObjectVars),
 190       weak_ptr_factory_(this) {
 191 }
 192
 193 gin::ObjectTemplateBuilder MessageChannel::GetObjectTemplateBuilder(
 194     v8::Isolate* isolate) {
 195   return Wrappable<MessageChannel>::GetObjectTemplateBuilder(isolate)
 196       .AddNamedPropertyInterceptor();
 197 }
 198
 199 void MessageChannel::BeginBlockOnSyncMessage() {
 200   js_message_queue_state_ = QUEUE_MESSAGES;
 201   ++blocking_message_depth_;
 202 }
 203
 204 void MessageChannel::EndBlockOnSyncMessage() {
 205   DCHECK_GT(blocking_message_depth_, 0);
 206   --blocking_message_depth_;
 207   if (!blocking_message_depth_)
 208     DrainJSMessageQueueSoon();
 209 }
 210
 211 v8::Local<v8::Value> MessageChannel::GetNamedProperty(
 212     v8::Isolate* isolate,
 213     const std::string& identifier) {
 214   if (!instance_)
 215     return v8::Local<v8::Value>();
 216
 217   PepperTryCatchV8 try_catch(instance_, &var_converter_, isolate);
 218   if (identifier == kPostMessage) {
 219     return gin::CreateFunctionTemplate(isolate,
 220         base::Bind(&MessageChannel::PostMessageToNative,
 221                    weak_ptr_factory_.GetWeakPtr()))->GetFunction();
 222   } else if (identifier == kPostMessageAndAwaitResponse) {
 223     return gin::CreateFunctionTemplate(isolate,
 224         base::Bind(&MessageChannel::PostBlockingMessageToNative,
 225                    weak_ptr_factory_.GetWeakPtr()))->GetFunction();
 226   }
 227
 228   std::map<std::string, ScopedPPVar>::const_iterator it =
 229       internal_named_properties_.find(identifier);
 230   if (it != internal_named_properties_.end()) {
 231     v8::Handle<v8::Value> result = try_catch.ToV8(it->second.get());
 232     if (try_catch.ThrowException())
 233       return v8::Local<v8::Value>();
 234     return result;
 235   }
 236
 237   PluginObject* plugin_object = GetPluginObject(isolate);
 238   if (plugin_object)
 239     return plugin_object->GetNamedProperty(isolate, identifier);
 240   return v8::Local<v8::Value>();
 241 }
 242
 243 bool MessageChannel::SetNamedProperty(v8::Isolate* isolate,
 244                                       const std::string& identifier,
 245                                       v8::Local<v8::Value> value) {
 246   if (!instance_)
 247     return false;
 248   PepperTryCatchV8 try_catch(instance_, &var_converter_, isolate);
 249   if (identifier == kPostMessage ||
 250       identifier == kPostMessageAndAwaitResponse) {
 251     try_catch.ThrowException("Cannot set properties with the name postMessage"
 252                              "or postMessageAndAwaitResponse");
 253     return true;
 254   }
 255
 256   // TODO(raymes): This is only used by the gTalk plugin which is deprecated.
 257   // Remove passthrough of SetProperty calls as soon as it is removed.
 258   PluginObject* plugin_object = GetPluginObject(isolate);
 259   if (plugin_object)
 260     return plugin_object->SetNamedProperty(isolate, identifier, value);
 261
 262   return false;
 263 }
 264
 265 std::vector<std::string> MessageChannel::EnumerateNamedProperties(
 266     v8::Isolate* isolate) {
 267   std::vector<std::string> result;
 268   PluginObject* plugin_object = GetPluginObject(isolate);
 269   if (plugin_object)
 270     result = plugin_object->EnumerateNamedProperties(isolate);
 271   result.push_back(kPostMessage);
 272   result.push_back(kPostMessageAndAwaitResponse);
 273   return result;
 274 }
 275
 276 void MessageChannel::PostMessageToNative(gin::Arguments* args) {
 277   if (!instance_)
 278     return;
 279   if (args->Length() != 1) {
 280     // TODO(raymes): Consider throwing an exception here. We don't now for
 281     // backward compatibility.
 282     return;
 283   }
 284
 285   v8::Handle<v8::Value> message_data;
 286   if (!args->GetNext(&message_data)) {
 287     NOTREACHED();
 288   }
 289
 290   EnqueuePluginMessage(message_data);
 291   DrainCompletedPluginMessages();
 292 }
 293
 294 void MessageChannel::PostBlockingMessageToNative(gin::Arguments* args) {
 295   if (!instance_)
 296     return;
 297   PepperTryCatchV8 try_catch(instance_, &var_converter_, args->isolate());
 298   if (args->Length() != 1) {
 299     try_catch.ThrowException(
 300         "postMessageAndAwaitResponse requires one argument");
 301     return;
 302   }
 303
 304   v8::Handle<v8::Value> message_data;
 305   if (!args->GetNext(&message_data)) {
 306     NOTREACHED();
 307   }
 308
 309   if (plugin_message_queue_state_ == WAITING_TO_START) {
 310     try_catch.ThrowException(
 311         "Attempted to call a synchronous method on a plugin that was not "
 312         "yet loaded.");
 313     return;
 314   }
 315
 316   // If the queue of messages to the plugin is non-empty, we're still waiting on
 317   // pending Var conversions. This means at some point in the past, JavaScript
 318   // called postMessage (the async one) and passed us something with a browser-
 319   // side host (e.g., FileSystem) and we haven't gotten a response from the
 320   // browser yet. We can't currently support sending a sync message if the
 321   // plugin does this, because it will break the ordering of the messages
 322   // arriving at the plugin.
 323   // TODO(dmichael): Fix this.
 324   // See https://code.google.com/p/chromium/issues/detail?id=367896#c4
 325   if (!plugin_message_queue_.empty()) {
 326     try_catch.ThrowException(
 327         "Failed to convert parameter synchronously, because a prior "
 328         "call to postMessage contained a type which required asynchronous "
 329         "transfer which has not completed. Not all types are supported yet by "
 330         "postMessageAndAwaitResponse. See crbug.com/367896.");
 331     return;
 332   }
 333   ScopedPPVar param = try_catch.FromV8(message_data);
 334   if (try_catch.ThrowException())
 335     return;
 336
 337   ScopedPPVar pp_result;
 338   bool was_handled = instance_->HandleBlockingMessage(param, &pp_result);
 339   if (!was_handled) {
 340     try_catch.ThrowException(
 341         "The plugin has not registered a handler for synchronous messages. "
 342         "See the documentation for PPB_Messaging::RegisterMessageHandler "
 343         "and PPP_MessageHandler.");
 344     return;
 345   }
 346   v8::Handle<v8::Value> v8_result = try_catch.ToV8(pp_result.get());
 347   if (try_catch.ThrowException())
 348     return;
 349
 350   args->Return(v8_result);
 351 }
 352
 353 void MessageChannel::PostMessageToJavaScriptImpl(
 354     const WebSerializedScriptValue& message_data) {
 355   DCHECK(instance_);
 356
 357   WebPluginContainer* container = instance_->container();
 358   // It's possible that container() is NULL if the plugin has been removed from
 359   // the DOM (but the PluginInstance is not destroyed yet).
 360   if (!container)
 361     return;
 362
 363   WebDOMEvent event =
 364       container->element().document().createEvent("MessageEvent");
 365   WebDOMMessageEvent msg_event = event.to<WebDOMMessageEvent>();
 366   msg_event.initMessageEvent("message",     // type
 367                              false,         // canBubble
 368                              false,         // cancelable
 369                              message_data,  // data
 370                              "",            // origin [*]
 371                              NULL,          // source [*]
 372                              "");           // lastEventId
 373   // [*] Note that the |origin| is only specified for cross-document and server-
 374   //     sent messages, while |source| is only specified for cross-document
 375   //     messages:
 376   //      http://www.whatwg.org/specs/web-apps/current-work/multipage/comms.html
 377   //     This currently behaves like Web Workers. On Firefox, Chrome, and Safari
 378   //     at least, postMessage on Workers does not provide the origin or source.
 379   //     TODO(dmichael):  Add origin if we change to a more iframe-like origin
 380   //                      policy (see crbug.com/81537)
 381   container->element().dispatchEvent(msg_event);
 382 }
 383
 384 PluginObject* MessageChannel::GetPluginObject(v8::Isolate* isolate) {
 385   return PluginObject::FromV8Object(isolate,
 386       v8::Local<v8::Object>::New(isolate, passthrough_object_));
 387 }
 388
 389 void MessageChannel::EnqueuePluginMessage(v8::Handle<v8::Value> v8_value) {
 390   plugin_message_queue_.push_back(VarConversionResult());
 391   // Convert the v8 value in to an appropriate PP_Var like Dictionary,
 392   // Array, etc. (We explicitly don't want an "Object" PP_Var, which we don't
 393   // support for Messaging.)
 394   // TODO(raymes): Possibly change this to use TryCatch to do the conversion and
 395   // throw an exception if necessary.
 396   V8VarConverter::VarResult conversion_result =
 397       var_converter_.FromV8Value(
 398           v8_value,
 399           v8::Isolate::GetCurrent()->GetCurrentContext(),
 400           base::Bind(&MessageChannel::FromV8ValueComplete,
 401                      weak_ptr_factory_.GetWeakPtr(),
 402                      &plugin_message_queue_.back()));
 403   if (conversion_result.completed_synchronously) {
 404     plugin_message_queue_.back().ConversionCompleted(
 405         conversion_result.var,
 406         conversion_result.success);
 407   }
 408 }
 409
 410 void MessageChannel::FromV8ValueComplete(VarConversionResult* result_holder,
 411                                          const ScopedPPVar& result,
 412                                          bool success) {
 413   if (!instance_)
 414     return;
 415   result_holder->ConversionCompleted(result, success);
 416   DrainCompletedPluginMessages();
 417 }
 418
 419 void MessageChannel::DrainCompletedPluginMessages() {
 420   DCHECK(instance_);
 421   if (plugin_message_queue_state_ == WAITING_TO_START)
 422     return;
 423
 424   while (!plugin_message_queue_.empty() &&
 425          plugin_message_queue_.front().conversion_completed()) {
 426     const VarConversionResult& front = plugin_message_queue_.front();
 427     if (front.success()) {
 428       instance_->HandleMessage(front.var());
 429     } else {
 430       PpapiGlobals::Get()->LogWithSource(instance()->pp_instance(),
 431                                          PP_LOGLEVEL_ERROR,
 432                                          std::string(),
 433                                          kV8ToVarConversionError);
 434     }
 435     plugin_message_queue_.pop_front();
 436   }
 437 }
 438
 439 void MessageChannel::DrainJSMessageQueue() {
 440   if (!instance_)
 441     return;
 442   if (js_message_queue_state_ == SEND_DIRECTLY)
 443     return;
 444
 445   // Take a reference on the PluginInstance. This is because JavaScript code
 446   // may delete the plugin, which would destroy the PluginInstance and its
 447   // corresponding MessageChannel.
 448   scoped_refptr<PepperPluginInstanceImpl> instance_ref(instance_);
 449   while (!js_message_queue_.empty()) {
 450     PostMessageToJavaScriptImpl(js_message_queue_.front());
 451     js_message_queue_.pop_front();
 452   }
 453   js_message_queue_state_ = SEND_DIRECTLY;
 454 }
 455
 456 void MessageChannel::DrainJSMessageQueueSoon() {
 457   base::MessageLoop::current()->PostTask(
 458       FROM_HERE,
 459       base::Bind(&MessageChannel::DrainJSMessageQueue,
 460                  weak_ptr_factory_.GetWeakPtr()));
 461 }
 462
 463 void MessageChannel::UnregisterSyncMessageStatusObserver() {
 464   if (!unregister_observer_callback_.is_null()) {
 465     unregister_observer_callback_.Run();
 466     unregister_observer_callback_.Reset();
 467   }
 468 }
 469
 470 }  // namespace content