HTML MessagePort as mojo::MessagePipeHandle

content/browser/message_port_service.cc

-// Copyright 2013 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 "content/browser/message_port_service.h"
-
-#include <stddef.h>
-
-#include "content/common/message_port_messages.h"
-#include "content/public/browser/browser_thread.h"
-#include "content/public/browser/message_port_delegate.h"
-
-namespace content {
-
-struct MessagePortService::MessagePort {
-  // |delegate| and |route_id| are what we need to send messages to the port.
-  // |delegate| is just a raw pointer since it notifies us by calling
-  // OnMessagePortDelegateClosing before it gets destroyed.
-  MessagePortDelegate* delegate;
-  int route_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.
-  // This is needed so that when a message port is sent between processes all
-  // pending message get transferred. There are two possibilities for pending
-  // messages: either they are already received by the child process, or they're
-  // in-flight. This flag ensures that the latter type get flushed through the
-  // system.
-  // This flag should only be set to true in response to
-  // MessagePortHostMsg_QueueMessages.
-  bool queue_for_inflight_messages;
-  // If true, all messages to this message port are queued and not delivered.
-  // This is needed so that when a message port is sent to a new process all
-  // messages are held in the browser process until the destination process is
-  // ready to receive messages. This flag is set true when a message port is
-  // transferred to a different process but there isn't immediately a
-  // MessagePortDelegate available for that new process. Once the
-  // destination process is ready to receive messages it sends
-  // MessagePortHostMsg_ReleaseMessages to set this flag to false.
-  bool hold_messages_for_destination;
-  // Returns true if messages should be queued for either reason.
-  bool queue_messages() const {
-    return queue_for_inflight_messages || hold_messages_for_destination;
-  }
-  // If true, the message port should be destroyed but was currently still
-  // waiting for a SendQueuedMessages message from a renderer. As soon as that
-  // message is received the port will actually be destroyed.
-  bool should_be_destroyed;
-  QueuedMessages queued_messages;
-};
-
-MessagePortService* MessagePortService::GetInstance() {
-  return base::Singleton<MessagePortService>::get();
-}
-
-MessagePortService::MessagePortService()
-    : next_message_port_id_(0) {
-}
-
-MessagePortService::~MessagePortService() {
-}
-
-void MessagePortService::UpdateMessagePort(int message_port_id,
-                                           MessagePortDelegate* delegate,
-                                           int routing_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!message_ports_.count(message_port_id)) {
-    NOTREACHED();
-    return;
-  }
-
-  MessagePort& port = message_ports_[message_port_id];
-  port.delegate = delegate;
-  port.route_id = routing_id;
-}
-
-void MessagePortService::GetMessagePortInfo(int message_port_id,
-                                            MessagePortDelegate** delegate,
-                                            int* routing_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!message_ports_.count(message_port_id)) {
-    NOTREACHED();
-    return;
-  }
-
-  const MessagePort& port = message_ports_[message_port_id];
-  if (delegate)
-    *delegate = port.delegate;
-  if (routing_id)
-    *routing_id = port.route_id;
-}
-
-void MessagePortService::OnMessagePortDelegateClosing(
-    MessagePortDelegate* delegate) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  // 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.delegate == delegate) {
-      Erase(cur_item->first);
-    }
-  }
-}
-
-void MessagePortService::Create(int route_id,
-                                MessagePortDelegate* delegate,
-                                int* message_port_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  *message_port_id = ++next_message_port_id_;
-
-  MessagePort port;
-  port.delegate = delegate;
-  port.route_id = route_id;
-  port.message_port_id = *message_port_id;
-  port.entangled_message_port_id = MSG_ROUTING_NONE;
-  port.queue_for_inflight_messages = false;
-  port.hold_messages_for_destination = false;
-  port.should_be_destroyed = false;
-  message_ports_[*message_port_id] = port;
-}
-
-void MessagePortService::Destroy(int message_port_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!message_ports_.count(message_port_id)) {
-    NOTREACHED();
-    return;
-  }
-
-  DCHECK(message_ports_[message_port_id].queued_messages.empty());
-
-  Erase(message_port_id);
-}
-
-void MessagePortService::Entangle(int local_message_port_id,
-                                  int remote_message_port_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  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 MessagePortService::PostMessage(
-    int sender_message_port_id,
-    const base::string16& message,
-    const std::vector<int>& sent_message_ports) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  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_ports);
-}
-
-void MessagePortService::PostMessageTo(
-    int message_port_id,
-    const base::string16& message,
-    const std::vector<int>& sent_message_ports) {
-  if (!message_ports_.count(message_port_id)) {
-    NOTREACHED();
-    return;
-  }
-  for (size_t i = 0; i < sent_message_ports.size(); ++i) {
-    if (!message_ports_.count(sent_message_ports[i])) {
-      NOTREACHED();
-      return;
-    }
-  }
-
-  MessagePort& entangled_port = message_ports_[message_port_id];
-  if (entangled_port.queue_messages()) {
-    // If the target port is currently holding messages because the destination
-    // renderer isn't available yet, all message ports being sent should also be
-    // put in this state.
-    if (entangled_port.hold_messages_for_destination) {
-      for (const auto& port : sent_message_ports)
-        HoldMessages(port);
-    }
-    entangled_port.queued_messages.push_back(
-        std::make_pair(message, sent_message_ports));
-    return;
-  }
-
-  if (!entangled_port.delegate) {
-    NOTREACHED();
-    return;
-  }
-
-  // Now send the message to the entangled port.
-  entangled_port.delegate->SendMessage(entangled_port.route_id, message,
-                                       sent_message_ports);
-}
-
-void MessagePortService::QueueMessages(int message_port_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!message_ports_.count(message_port_id)) {
-    NOTREACHED();
-    return;
-  }
-
-  MessagePort& port = message_ports_[message_port_id];
-  if (port.delegate) {
-    port.delegate->SendMessagesAreQueued(port.route_id);
-    port.queue_for_inflight_messages = true;
-    port.delegate = NULL;
-  }
-}
-
-void MessagePortService::SendQueuedMessages(
-    int message_port_id,
-    const QueuedMessages& queued_messages) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  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_for_inflight_messages = false;
-
-  // If the port is currently holding messages waiting for the target renderer,
-  // all ports in messages being sent to the port should also be put on hold.
-  if (port.hold_messages_for_destination) {
-    for (const auto& message : queued_messages)
-      for (int sent_port : message.second)
-        HoldMessages(sent_port);
-  }
-
-  port.queued_messages.insert(port.queued_messages.begin(),
-                              queued_messages.begin(),
-                              queued_messages.end());
-
-  if (port.should_be_destroyed)
-    ClosePort(message_port_id);
-  else
-    SendQueuedMessagesIfPossible(message_port_id);
-}
-
-void MessagePortService::SendQueuedMessagesIfPossible(int message_port_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!message_ports_.count(message_port_id)) {
-    NOTREACHED();
-    return;
-  }
-
-  MessagePort& port = message_ports_[message_port_id];
-  if (port.queue_messages() || !port.delegate)
-    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 MessagePortService::HoldMessages(int message_port_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!message_ports_.count(message_port_id)) {
-    NOTREACHED();
-    return;
-  }
-
-  // Any ports in messages currently in the queue should also be put on hold.
-  for (const auto& message : message_ports_[message_port_id].queued_messages)
-    for (int sent_port : message.second)
-      HoldMessages(sent_port);
-
-  message_ports_[message_port_id].hold_messages_for_destination = true;
-}
-
-bool MessagePortService::AreMessagesHeld(int message_port_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!message_ports_.count(message_port_id))
-    return false;
-  return message_ports_[message_port_id].hold_messages_for_destination;
-}
-
-void MessagePortService::ClosePort(int message_port_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!message_ports_.count(message_port_id)) {
-    NOTREACHED();
-    return;
-  }
-
-  if (message_ports_[message_port_id].queue_for_inflight_messages) {
-    message_ports_[message_port_id].should_be_destroyed = true;
-    return;
-  }
-
-  // First close any message ports in the queue for this message port.
-  for (const auto& message : message_ports_[message_port_id].queued_messages)
-    for (int sent_port : message.second)
-      ClosePort(sent_port);
-
-  Erase(message_port_id);
-}
-
-void MessagePortService::ReleaseMessages(int message_port_id) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!message_ports_.count(message_port_id)) {
-    NOTREACHED();
-    return;
-  }
-
-  message_ports_[message_port_id].hold_messages_for_destination = false;
-  SendQueuedMessagesIfPossible(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);
-}
-
-}  // namespace content