plugins: use OnChannelError to detect when the channel goes away

chrome/common/child_process_host.cc

 // Copyright (c) 2009 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/common/child_process_host.h"
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/process_util.h"
@@ skipping 33 matching lines @@
 
 }  // namespace
 
 
 
 ChildProcessHost::ChildProcessHost(
     ProcessType type, ResourceDispatcherHost* resource_dispatcher_host)
     : Receiver(type),
       ALLOW_THIS_IN_INITIALIZER_LIST(listener_(this)),
       resource_dispatcher_host_(resource_dispatcher_host),
-      opening_channel_(false),
-      process_event_(NULL) {
+      opening_channel_(false) {
   Singleton<ChildProcessList>::get()->push_back(this);
 }
 
 
 ChildProcessHost::~ChildProcessHost() {
   Singleton<ChildProcessList>::get()->remove(this);
 
   resource_dispatcher_host_->CancelRequestsForProcess(GetProcessId());
 
-  if (handle()) {
-    watcher_.StopWatching();
+  if (handle())
     ProcessWatcher::EnsureProcessTerminated(handle());
-
-#if defined(OS_WIN)
-    // Above call took ownership, so don't want WaitableEvent to assert because
-    // the handle isn't valid anymore.
-    process_event_->Release();
-#endif
-  }
 }
 
 bool ChildProcessHost::CreateChannel() {
   channel_id_ = GenerateRandomChannelID(this);
   channel_.reset(new IPC::Channel(
       channel_id_, IPC::Channel::MODE_SERVER, &listener_));
   if (!channel_->Connect())
     return false;
 
   opening_channel_ = true;
 
   return true;
 }
 
 void ChildProcessHost::SetHandle(base::ProcessHandle process) {
-#if defined(OS_WIN)
-  process_event_.reset(new base::WaitableEvent(process));
-
   DCHECK(!handle());
   set_handle(process);
-  watcher_.StartWatching(process_event_.get(), this);
-#endif
 }
 
 void ChildProcessHost::InstanceCreated() {
   Notify(NotificationType::CHILD_INSTANCE_CREATED);
 }
 
 bool ChildProcessHost::Send(IPC::Message* msg) {
   if (!channel_.get()) {
     delete msg;
     return false;
   }
   return channel_->Send(msg);
 }
 
 void ChildProcessHost::Notify(NotificationType type) {
   resource_dispatcher_host_->ui_loop()->PostTask(
       FROM_HERE, new ChildNotificationTask(type, this));
 }
 
-void ChildProcessHost::OnWaitableEventSignaled(base::WaitableEvent *event) {
-#if defined(OS_WIN)
-  HANDLE object = event->handle();
+void ChildProcessHost::OnChildDied() {
   DCHECK(handle());
-  DCHECK_EQ(object, handle());
 
-  bool did_crash = base::DidProcessCrash(NULL, object);
+  bool did_crash = base::DidProcessCrash(NULL, handle());
   if (did_crash) {
     // Report that this child process crashed.
     Notify(NotificationType::CHILD_PROCESS_CRASHED);
   }
   // Notify in the main loop of the disconnection.
   Notify(NotificationType::CHILD_PROCESS_HOST_DISCONNECTED);
-#endif
+
+  // On POSIX, once we've called DidProcessCrash, handle() is no longer
+  // valid.  Ensure the destructor doesn't try to use it.
+  set_handle(NULL);
 
   delete this;
 }
 
 ChildProcessHost::ListenerHook::ListenerHook(ChildProcessHost* host)
     : host_(host) {
 }
 
 void ChildProcessHost::ListenerHook::OnMessageReceived(
     const IPC::Message& msg) {
@@ skipping 38 matching lines @@
   host_->OnChannelConnected(peer_pid);
   host_->Send(new PluginProcessMsg_AskBeforeShutdown());
 
   // Notify in the main loop of the connection.
   host_->Notify(NotificationType::CHILD_PROCESS_HOST_CONNECTED);
 }
 
 void ChildProcessHost::ListenerHook::OnChannelError() {
   host_->opening_channel_ = false;
   host_->OnChannelError();
+
+  // This will delete host_, which will also destroy this!
+  host_->OnChildDied();
 }
 
 
 ChildProcessHost::Iterator::Iterator() : all_(true) {
   DCHECK(MessageLoop::current() ==
       ChromeThread::GetMessageLoop(ChromeThread::IO)) <<
           "ChildProcessInfo::Iterator must be used on the IO thread.";
   iterator_ = Singleton<ChildProcessList>::get()->begin();
 }
 
@@ skipping 18 matching lines @@
 
     return *iterator_;
   } while (true);
 
   return NULL;
 }
 
 bool ChildProcessHost::Iterator::Done() {
   return iterator_ == Singleton<ChildProcessList>::get()->end();
 }