Create a message filter for message port messages. This allows a nice cleanu...

chrome/browser/worker_host/message_port_service.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/browser/worker_host/message_port_dispatcher.h"
+#include "chrome/browser/worker_host/message_port_service.h"
 
-#include "base/callback.h"
-#include "base/singleton.h"
-#include "chrome/browser/renderer_host/render_message_filter.h"
-#include "chrome/browser/worker_host/worker_process_host.h"
-#include "chrome/common/notification_service.h"
+#include "chrome/browser/worker_host/worker_message_filter.h"
 #include "chrome/common/worker_messages.h"
 
-struct MessagePortDispatcher::MessagePort {
-  // sender and route_id are what we need to send messages to the port.
-  IPC::Message::Sender* sender;
+struct MessagePortService::MessagePort {
+  // |filter| and |route_id| are what we need to send messages to the port.
+  // |filter| is just a weak pointer since we get notified when its process has
+  // gone away and remove it.
+  WorkerMessageFilter* filter;
   int route_id;
-  // A function pointer to generate a new route id for the sender above.
-  // Owned by "sender" above, so don't delete.
-  CallbackWithReturnValue<int>::Type* next_routing_id;
   // A globally unique id for this message port.
   int message_port_id;
   // The globally unique id of the entangled message port.
   int entangled_message_port_id;
   // If true, all messages to this message port are queued and not delivered.
   bool queue_messages;
   QueuedMessages queued_messages;
 };
 
-MessagePortDispatcher* MessagePortDispatcher::GetInstance() {
-  return Singleton<MessagePortDispatcher>::get();
+MessagePortService* MessagePortService::GetInstance() {
+  return Singleton<MessagePortService>::get();
 }
 
-MessagePortDispatcher::MessagePortDispatcher()
-    : next_message_port_id_(0),
-      sender_(NULL),
-      next_routing_id_(NULL) {
-  // Receive a notification if a message filter or WorkerProcessHost is deleted.
-  registrar_.Add(this, NotificationType::RESOURCE_MESSAGE_FILTER_SHUTDOWN,
-                 NotificationService::AllSources());
-
-  registrar_.Add(this, NotificationType::WORKER_PROCESS_HOST_SHUTDOWN,
-                 NotificationService::AllSources());
+MessagePortService::MessagePortService()
+    : next_message_port_id_(0) {
 }
 
-MessagePortDispatcher::~MessagePortDispatcher() {
+MessagePortService::~MessagePortService() {
 }
 
-bool MessagePortDispatcher::OnMessageReceived(
-    const IPC::Message& message,
-    IPC::Message::Sender* sender,
-    CallbackWithReturnValue<int>::Type* next_routing_id,
-    bool* message_was_ok) {
-  sender_ = sender;
-  next_routing_id_ = next_routing_id;
-
-  bool handled = true;
-  *message_was_ok = true;
-
-  IPC_BEGIN_MESSAGE_MAP_EX(MessagePortDispatcher, message, *message_was_ok)
-    IPC_MESSAGE_HANDLER(WorkerProcessHostMsg_CreateMessagePort, OnCreate)
-    IPC_MESSAGE_HANDLER(WorkerProcessHostMsg_DestroyMessagePort, OnDestroy)
-    IPC_MESSAGE_HANDLER(WorkerProcessHostMsg_Entangle, OnEntangle)
-    IPC_MESSAGE_HANDLER(WorkerProcessHostMsg_PostMessage, OnPostMessage)
-    IPC_MESSAGE_HANDLER(WorkerProcessHostMsg_QueueMessages, OnQueueMessages)
-    IPC_MESSAGE_HANDLER(WorkerProcessHostMsg_SendQueuedMessages,
-                        OnSendQueuedMessages)
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP_EX()
-
-  sender_ = NULL;
-  next_routing_id_ = NULL;
-
-  return handled;
-}
-
-void MessagePortDispatcher::UpdateMessagePort(
+void MessagePortService::UpdateMessagePort(
     int message_port_id,
-    IPC::Message::Sender* sender,
-    int routing_id,
-    CallbackWithReturnValue<int>::Type* next_routing_id) {
+     WorkerMessageFilter* filter,

[Andrew T Wilson (Slow), 2010/12/21 03:12:21]

Remove extra space at front

[jam, 2010/12/21 07:41:51]

Done.

+    int routing_id) {
   if (!message_ports_.count(message_port_id)) {
     NOTREACHED();
     return;
   }
 
   MessagePort& port = message_ports_[message_port_id];
-  port.sender = sender;
+  port.filter = filter;
   port.route_id = routing_id;
-  port.next_routing_id = next_routing_id;
 }
 
-bool MessagePortDispatcher::Send(IPC::Message* message) {
-  return sender_->Send(message);
+void MessagePortService::OnWorkerMessageFilterClosing(
+    WorkerMessageFilter* filter) {
+  // Check if the (possibly) crashed process had any message ports.
+  for (MessagePorts::iterator iter = message_ports_.begin();
+       iter != message_ports_.end();) {
+    MessagePorts::iterator cur_item = iter++;
+    if (cur_item->second.filter == filter) {
+      Erase(cur_item->first);
+    }
+  }
 }
 
-void MessagePortDispatcher::OnCreate(int *route_id,
-                                     int* message_port_id) {
+void MessagePortService::Create(int route_id,
+                                WorkerMessageFilter* filter,
+                                int* message_port_id) {
   *message_port_id = ++next_message_port_id_;
-  *route_id = next_routing_id_->Run();
 
   MessagePort port;
-  port.sender = sender_;
-  port.route_id = *route_id;
-  port.next_routing_id = next_routing_id_;
+  port.filter = filter;
+  port.route_id = route_id;
   port.message_port_id = *message_port_id;
   port.entangled_message_port_id = MSG_ROUTING_NONE;
   port.queue_messages = false;
   message_ports_[*message_port_id] = port;
 }
 
-void MessagePortDispatcher::OnDestroy(int message_port_id) {
+void MessagePortService::Destroy(int message_port_id) {
   if (!message_ports_.count(message_port_id)) {
     NOTREACHED();
     return;
   }
 
   DCHECK(message_ports_[message_port_id].queued_messages.empty());
   Erase(message_port_id);
 }
 
-void MessagePortDispatcher::OnEntangle(int local_message_port_id,
-                                       int remote_message_port_id) {
+void MessagePortService::Entangle(int local_message_port_id,
+                                  int remote_message_port_id) {
   if (!message_ports_.count(local_message_port_id) ||
       !message_ports_.count(remote_message_port_id)) {
     NOTREACHED();
     return;
   }
 
   DCHECK(message_ports_[remote_message_port_id].entangled_message_port_id ==
       MSG_ROUTING_NONE);
   message_ports_[remote_message_port_id].entangled_message_port_id =
       local_message_port_id;
 }
 
-void MessagePortDispatcher::OnPostMessage(
+void MessagePortService::PostMessage(
     int sender_message_port_id,
     const string16& message,
     const std::vector<int>& sent_message_port_ids) {
   if (!message_ports_.count(sender_message_port_id)) {
     NOTREACHED();
     return;
   }
 
   int entangled_message_port_id =
       message_ports_[sender_message_port_id].entangled_message_port_id;
   if (entangled_message_port_id == MSG_ROUTING_NONE)
     return;  // Process could have crashed.
 
   if (!message_ports_.count(entangled_message_port_id)) {
     NOTREACHED();
     return;
   }
 
   PostMessageTo(entangled_message_port_id, message, sent_message_port_ids);
 }
 
-void MessagePortDispatcher::PostMessageTo(
+void MessagePortService::PostMessageTo(
     int message_port_id,
     const string16& message,
     const std::vector<int>& sent_message_port_ids) {
   if (!message_ports_.count(message_port_id)) {
     NOTREACHED();
     return;
   }
   for (size_t i = 0; i < sent_message_port_ids.size(); ++i) {
     if (!message_ports_.count(sent_message_port_ids[i])) {
       NOTREACHED();
@@ skipping 11 matching lines @@
 
   if (entangled_port.queue_messages) {
     entangled_port.queued_messages.push_back(
         std::make_pair(message, sent_message_port_ids));
   } else {
     // If a message port was sent around, the new location will need a routing
     // id.  Instead of having the created port send us a sync message to get it,
     // send along with the message.
     std::vector<int> new_routing_ids(sent_message_port_ids.size());
     for (size_t i = 0; i < sent_message_port_ids.size(); ++i) {
-      new_routing_ids[i] = entangled_port.next_routing_id->Run();
-      sent_ports[i]->sender = entangled_port.sender;
+      new_routing_ids[i] = entangled_port.filter->GetNextRoutingID();
+      sent_ports[i]->filter = entangled_port.filter;
 
       // Update the entry for the sent port as it can be in a different process.
       sent_ports[i]->route_id = new_routing_ids[i];
     }
 
-    if (entangled_port.sender) {
+    if (entangled_port.filter) {

[Andrew T Wilson (Slow), 2010/12/21 03:12:21]

If entangled_port.filter is null here, then we would have crashed in the
previous for loop when we called entangled_port.filter->GetNextRoutingID(). So I
think we need to do something different here if we ever can get called with a
null filter (I'm not sure what that case is - is that the case when you've send
a port to another process, so the original port is now unentangled)?

[jam, 2010/12/21 07:41:51]

good point, made the "else" be an "else if" and added a comment wondering if it
can be null.  i don't know which situation this can happen, if any, so went the
safe route for now.

       // Now send the message to the entangled port.
-      IPC::Message* ipc_msg = new WorkerProcessMsg_Message(
+      entangled_port.filter->Send(new WorkerProcessMsg_Message(
           entangled_port.route_id, message, sent_message_port_ids,
-          new_routing_ids);
-      entangled_port.sender->Send(ipc_msg);
+          new_routing_ids));
     }
   }
 }
 
-void MessagePortDispatcher::OnQueueMessages(int message_port_id) {
+void MessagePortService::QueueMessages(int message_port_id) {
   if (!message_ports_.count(message_port_id)) {
     NOTREACHED();
     return;
   }
 
   MessagePort& port = message_ports_[message_port_id];
-  if (port.sender) {
-    port.sender->Send(new WorkerProcessMsg_MessagesQueued(port.route_id));
+  if (port.filter) {
+    port.filter->Send(new WorkerProcessMsg_MessagesQueued(port.route_id));
     port.queue_messages = true;
-    port.sender = NULL;
+    port.filter = NULL;

[Andrew T Wilson (Slow), 2010/12/21 03:12:21]

Coming back to this code after a several-month hiatus, I am now realizing that I
don't entirely recall what case this is covering. It would be useful to add a
comment to some of these routines explaining when they are called (called when a
port is being sent to another process, etc).

[jam, 2010/12/21 07:41:51]

I'd love to add some good comments, but I haven't touched this code in over a
year so I'd prefer not to add extra comments in case they're off

   }
 }
 
-void MessagePortDispatcher::OnSendQueuedMessages(
+void MessagePortService::SendQueuedMessages(
     int message_port_id,
     const QueuedMessages& queued_messages) {
   if (!message_ports_.count(message_port_id)) {
     NOTREACHED();
     return;
   }
 
   // Send the queued messages to the port again.  This time they'll reach the
   // new location.
   MessagePort& port = message_ports_[message_port_id];
   port.queue_messages = false;
   port.queued_messages.insert(port.queued_messages.begin(),
                               queued_messages.begin(),
                               queued_messages.end());
   SendQueuedMessagesIfPossible(message_port_id);
 }
 
-void MessagePortDispatcher::SendQueuedMessagesIfPossible(int message_port_id) {
+void MessagePortService::SendQueuedMessagesIfPossible(int message_port_id) {
   if (!message_ports_.count(message_port_id)) {
     NOTREACHED();
     return;
   }
 
   MessagePort& port = message_ports_[message_port_id];
-  if (port.queue_messages || !port.sender)
+  if (port.queue_messages || !port.filter)
     return;
 
   for (QueuedMessages::iterator iter = port.queued_messages.begin();
        iter != port.queued_messages.end(); ++iter) {
     PostMessageTo(message_port_id, iter->first, iter->second);
   }
   port.queued_messages.clear();
 }
 
-void MessagePortDispatcher::Observe(NotificationType type,
-                                    const NotificationSource& source,
-                                    const NotificationDetails& details) {
-  IPC::Message::Sender* sender = NULL;
-  if (type.value == NotificationType::RESOURCE_MESSAGE_FILTER_SHUTDOWN) {
-    sender = Source<RenderMessageFilter>(source).ptr();
-  } else if (type.value == NotificationType::WORKER_PROCESS_HOST_SHUTDOWN) {
-    sender = Source<WorkerProcessHost>(source).ptr();
-  } else {
-    NOTREACHED();
-  }
-
-  // Check if the (possibly) crashed process had any message ports.
-  for (MessagePorts::iterator iter = message_ports_.begin();
-       iter != message_ports_.end();) {
-    MessagePorts::iterator cur_item = iter++;
-    if (cur_item->second.sender == sender) {
-      Erase(cur_item->first);
-    }
-  }
-}
-
-void MessagePortDispatcher::Erase(int message_port_id) {
+void MessagePortService::Erase(int message_port_id) {
   MessagePorts::iterator erase_item = message_ports_.find(message_port_id);
   DCHECK(erase_item != message_ports_.end());
 
   int entangled_id = erase_item->second.entangled_message_port_id;
   if (entangled_id != MSG_ROUTING_NONE) {
     // Do the disentanglement (and be paranoid about the other side existing
     // just in case something unusual happened during entanglement).
     if (message_ports_.count(entangled_id)) {
       message_ports_[entangled_id].entangled_message_port_id = MSG_ROUTING_NONE;
     }
   }
   message_ports_.erase(erase_item);
 }