[mojo-edk] Simplify multiprocess pipe bootstrap

mojo/edk/system/node_controller.cc

 // Copyright 2016 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 "mojo/edk/system/node_controller.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/bind.h"
@@ skipping 81 matching lines @@
     delete this;
   }
 
   const base::Closure callback_;
 
   DISALLOW_COPY_AND_ASSIGN(ThreadDestructionObserver);
 };
 
 }  // namespace
 
-NodeController::PendingPortRequest::PendingPortRequest() {}
-
-NodeController::PendingPortRequest::~PendingPortRequest() {}
-
-NodeController::ReservedPort::ReservedPort() {}
-
-NodeController::ReservedPort::~ReservedPort() {}
-
-NodeController::PendingRemotePortConnection::PendingRemotePortConnection() {}
-
-NodeController::PendingRemotePortConnection::~PendingRemotePortConnection() {}
-
 NodeController::~NodeController() {}
 
 NodeController::NodeController(Core* core)
     : core_(core),
       name_(GetRandomNodeName()),
       node_(new ports::Node(name_, this)) {
   DVLOG(1) << "Initializing node " << name_;
 }
 
 void NodeController::SetIOTaskRunner(
@@ skipping 51 matching lines @@
   if (rv != ports::OK) {
     DCHECK(ports_message);
     message->reset(static_cast<PortsMessage*>(ports_message.release()));
   }
 
   AcceptIncomingMessages();
   return rv;
 }
 
 void NodeController::ReservePort(const std::string& token,
-                                 const ReservePortCallback& callback) {
-  ports::PortRef port;
-  node_->CreateUninitializedPort(&port);
-
+                                 const ports::PortRef& port) {
   DVLOG(2) << "Reserving port " << port.name() << "@" << name_ << " for token "
            << token;
 
   base::AutoLock lock(reserved_ports_lock_);
-  ReservedPort reservation;
-  reservation.local_port = port;
-  reservation.callback = callback;
-  reserved_ports_.insert(std::make_pair(token, reservation));
+  auto result = reserved_ports_.insert(std::make_pair(token, port));
+  DCHECK(result.second);
+}
+
+void NodeController::MergePortIntoParent(const std::string& token,
+                                         const ports::PortRef& port) {
+  scoped_refptr<NodeChannel> parent = GetParentChannel();
+  if (parent) {
+    parent->RequestPortMerge(port.name(), token);
+    return;
+  }
+
+  base::AutoLock lock(pending_port_merges_lock_);
+  pending_port_merges_.push_back(std::make_pair(token, port));
 }
 
 scoped_refptr<PlatformSharedBuffer> NodeController::CreateSharedBuffer(
     size_t num_bytes) {
   scoped_refptr<PlatformSharedBuffer> buffer =
       internal::g_platform_support->CreateSharedBuffer(num_bytes);
 #if defined(OS_POSIX)
   if (!buffer && broker_) {
     // On POSIX, creating a shared buffer in a sandboxed process will fail, so
     // fall back to the broker if there is one.
     buffer = broker_->GetSharedBuffer(num_bytes);
   }
 #endif
   return buffer;
 }
 
-void NodeController::ConnectToParentPort(const ports::PortRef& local_port,
-                                         const std::string& token,
-                                         const base::Closure& callback) {
-  io_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&NodeController::RequestParentPortConnectionOnIOThread,
-                 base::Unretained(this), local_port, token, callback));
-}
-
-void NodeController::ConnectToRemotePort(
-    const ports::PortRef& local_port,
-    const ports::NodeName& remote_node_name,
-    const ports::PortName& remote_port_name,
-    const base::Closure& callback) {
-  if (remote_node_name == name_) {
-    // It's possible that two different code paths on the node are trying to
-    // bootstrap ports to each other (e.g. in Chrome single-process mode)
-    // without being aware of the fact. In this case we can initialize the port
-    // immediately (which can fail silently if it's already been initialized by
-    // the request on the other side), and invoke |callback|.
-    node_->InitializePort(local_port, name_, remote_port_name);
-    callback.Run();
-    return;
-  }
-
-  PendingRemotePortConnection connection;
-  connection.local_port = local_port;
-  connection.remote_node_name = remote_node_name;
-  connection.remote_port_name = remote_port_name;
-  connection.callback = callback;
-  io_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&NodeController::ConnectToRemotePortOnIOThread,
-                 base::Unretained(this), connection));
-}
-
 void NodeController::RequestShutdown(const base::Closure& callback) {
   {
     base::AutoLock lock(shutdown_lock_);
     shutdown_callback_ = callback;
   }
 
   AttemptShutdownIfRequested();
 }
 
 void NodeController::ConnectToChildOnIOThread(
@@ skipping 38 matching lines @@
   DCHECK(parent_name_ == ports::kInvalidNodeName);
 
   // At this point we don't know the parent's name, so we can't yet insert it
   // into our |peers_| map. That will happen as soon as we receive an
   // AcceptChild message from them.
   bootstrap_parent_channel_ =
       NodeChannel::Create(this, std::move(platform_handle), io_task_runner_);
   bootstrap_parent_channel_->Start();
 }
 
-void NodeController::RequestParentPortConnectionOnIOThread(
-    const ports::PortRef& local_port,
-    const std::string& token,
-    const base::Closure& callback) {
-  DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
-
-  scoped_refptr<NodeChannel> parent = GetParentChannel();
-  if (!parent) {
-    PendingPortRequest request;
-    request.token = token;
-    request.local_port = local_port;
-    request.callback = callback;
-    pending_port_requests_.push_back(request);
-    return;
-  }
-
-  pending_parent_port_connections_.insert(
-      std::make_pair(local_port.name(), callback));
-  parent->RequestPortConnection(local_port.name(), token);
-}
-
-void NodeController::ConnectToRemotePortOnIOThread(
-    const PendingRemotePortConnection& connection) {
-  scoped_refptr<NodeChannel> peer = GetPeerChannel(connection.remote_node_name);
-  if (peer) {
-    // It's safe to initialize the port since we already have a channel to its
-    // peer. No need to actually send them a message.
-    int rv = node_->InitializePort(connection.local_port,
-                                   connection.remote_node_name,
-                                   connection.remote_port_name);
-    DCHECK_EQ(rv, ports::OK);
-    connection.callback.Run();
-    return;
-  }
-
-  // Save this for later. We'll initialize the port once this peer is added.
-  pending_remote_port_connections_[connection.remote_node_name].push_back(
-      connection);
-}
-
 scoped_refptr<NodeChannel> NodeController::GetPeerChannel(
     const ports::NodeName& name) {
   base::AutoLock lock(peers_lock_);
   auto it = peers_.find(name);
   if (it == peers_.end())
     return nullptr;
   return it->second;
 }
 
 scoped_refptr<NodeChannel> NodeController::GetParentChannel() {
@@ skipping 50 matching lines @@
   }
 
   if (start_channel)
     channel->Start();
 
   // Flush any queued message we need to deliver to this node.
   while (!pending_messages.empty()) {
     channel->PortsMessage(std::move(pending_messages.front()));
     pending_messages.pop();
   }
-
-  // Complete any pending port connections to this peer.
-  auto connections_it = pending_remote_port_connections_.find(name);
-  if (connections_it != pending_remote_port_connections_.end()) {
-    for (const auto& connection : connections_it->second) {
-      int rv = node_->InitializePort(connection.local_port,
-                                     connection.remote_node_name,
-                                     connection.remote_port_name);
-      DCHECK_EQ(rv, ports::OK);
-      connection.callback.Run();
-    }
-    pending_remote_port_connections_.erase(connections_it);
-  }
 }
 
 void NodeController::DropPeer(const ports::NodeName& name) {
   DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
 
   {
     base::AutoLock lock(peers_lock_);
     auto it = peers_.find(name);
 
     if (it != peers_.end()) {
@@ skipping 169 matching lines @@
     parent_name_ = parent_name;
     parent = bootstrap_parent_channel_;
   }
 
   parent->SetRemoteNodeName(parent_name);
   parent->AcceptParent(token, name_);
 
   // NOTE: The child does not actually add its parent as a peer until
   // receiving an AcceptBrokerClient message from the broker. The parent
   // will request that said message be sent upon receiving AcceptParent.
+
+  DVLOG(1) << "Child " << name_ << " accepting parent " << parent_name;
 }
 
 void NodeController::OnAcceptParent(const ports::NodeName& from_node,
                                     const ports::NodeName& token,
                                     const ports::NodeName& child_name) {
   DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
 
   auto it = pending_children_.find(from_node);
   if (it == pending_children_.end() || token != from_node) {
     DLOG(ERROR) << "Received unexpected AcceptParent message from "
@@ skipping 127 matching lines @@
   scoped_refptr<NodeChannel> broker;
   if (broker_name == parent_name) {
     DCHECK(!broker_channel.is_valid());
     broker = parent;
   } else {
     DCHECK(broker_channel.is_valid());
     broker = NodeChannel::Create(this, std::move(broker_channel),
                                  io_task_runner_);
     AddPeer(broker_name, broker, true /* start_channel */);
   }
+
   AddPeer(parent_name, parent, false /* start_channel */);
 
-  // Resolve any pending port connections to the parent.
-  for (const auto& request : pending_port_requests_) {
-    pending_parent_port_connections_.insert(
-        std::make_pair(request.local_port.name(), request.callback));
-    parent->RequestPortConnection(request.local_port.name(), request.token);
+  {
+    // Complete any port merge requests we have waiting for the parent.
+    base::AutoLock lock(pending_port_merges_lock_);
+    for (const auto& request : pending_port_merges_)
+      parent->RequestPortMerge(request.second.name(), request.first);
+    pending_port_merges_.clear();
   }
-  pending_port_requests_.clear();
 
   // Feed the broker any pending children of our own.
   while (!pending_broker_clients.empty()) {
     const ports::NodeName& child_name = pending_broker_clients.front();
     auto it = pending_children_.find(child_name);
     DCHECK(it != pending_children_.end());
     broker->AddBrokerClient(child_name, it->second->CopyRemoteProcessHandle());
     pending_broker_clients.pop();
   }
 
@@ skipping 32 matching lines @@
       new PortsMessage(num_header_bytes,
                        num_payload_bytes,
                        num_ports_bytes,
                        std::move(channel_message)));
 
   node_->AcceptMessage(std::move(message));
   AcceptIncomingMessages();
   AttemptShutdownIfRequested();
 }
 
-void NodeController::OnRequestPortConnection(
+void NodeController::OnRequestPortMerge(
     const ports::NodeName& from_node,
     const ports::PortName& connector_port_name,
     const std::string& token) {
   DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
 
-  DVLOG(2) << "Node " << name_ << " received RequestPortConnection for token "
+  DVLOG(2) << "Node " << name_ << " received RequestPortMerge for token "
            << token << " and port " << connector_port_name << "@" << from_node;
 
-  ReservePortCallback callback;
   ports::PortRef local_port;
   {
     base::AutoLock lock(reserved_ports_lock_);
     auto it = reserved_ports_.find(token);
     if (it == reserved_ports_.end()) {
       DVLOG(1) << "Ignoring request to connect to port for unknown token "
                << token;
       return;
     }
-    local_port = it->second.local_port;
-    callback = it->second.callback;
-    reserved_ports_.erase(it);
+    local_port = it->second;
   }
 
-  DCHECK(!callback.is_null());
-
-  scoped_refptr<NodeChannel> peer = GetPeerChannel(from_node);
-  if (!peer) {
-    DVLOG(1) << "Ignoring request to connect to port from unknown node "
-             << from_node;
-    return;
-  }
-
-  // This reserved port should not have been initialized yet.
-  CHECK_EQ(ports::OK, node_->InitializePort(local_port, from_node,
-                                            connector_port_name));
-
-  peer->ConnectToPort(local_port.name(), connector_port_name);
-  callback.Run(local_port);
-}
-
-void NodeController::OnConnectToPort(
-    const ports::NodeName& from_node,
-    const ports::PortName& connector_port_name,
-    const ports::PortName& connectee_port_name) {
-  DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
-
-  DVLOG(2) << "Node " << name_ << " received ConnectToPort for local port "
-           << connectee_port_name << " to port " << connector_port_name << "@"
-           << from_node;
-
-  ports::PortRef connectee_port;
-  int rv = node_->GetPort(connectee_port_name, &connectee_port);
-  if (rv != ports::OK) {
-    DLOG(ERROR) << "Ignoring ConnectToPort for unknown port "
-                << connectee_port_name;
-    return;
-  }
-
-  // It's OK if this port has already been initialized. This message is only
-  // sent by the remote peer to ensure the port is ready before it starts
-  // us sending messages to it.
-  ports::PortStatus port_status;
-  rv = node_->GetStatus(connectee_port, &port_status);
-  if (rv == ports::OK) {
-    DVLOG(1) << "Ignoring ConnectToPort for already-initialized port "
-             << connectee_port_name;
-    return;
-  }
-
-  CHECK_EQ(ports::OK, node_->InitializePort(connectee_port, from_node,
-                                            connector_port_name));
-
-  auto it = pending_parent_port_connections_.find(connectee_port_name);
-  DCHECK(it != pending_parent_port_connections_.end());
-  it->second.Run();
-  pending_parent_port_connections_.erase(it);
+  int rv = node_->MergePorts(local_port, from_node, connector_port_name);
+  if (rv != ports::OK)
+    DLOG(ERROR) << "MergePorts failed: " << rv;
 }
 
 void NodeController::OnRequestIntroduction(const ports::NodeName& from_node,
                                            const ports::NodeName& name) {
   DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
 
   scoped_refptr<NodeChannel> requestor = GetPeerChannel(from_node);
   if (from_node == name || name == ports::kInvalidNodeName || !requestor) {
     DLOG(ERROR) << "Rejecting invalid OnRequestIntroduction message from "
                 << from_node;
@@ skipping 101 matching lines @@
     shutdown_callback_.Reset();
   }
 
   DCHECK(!callback.is_null());
 
   callback.Run();
 }
 
 }  // namespace edk
 }  // namespace mojo