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