Revert of [mojo-edk] Simplify multiprocess pipe bootstrap

mojo/edk/system/node_controller.cc

Index: mojo/edk/system/node_controller.cc
diff --git a/mojo/edk/system/node_controller.cc b/mojo/edk/system/node_controller.cc
index 38c53df3b4cfc6d9e98f039e20a36c30fe12a346..6410caef5f71213d8757f8228fd884db6c30f0eb 100644
--- a/mojo/edk/system/node_controller.cc
+++ b/mojo/edk/system/node_controller.cc
@@ -99,6 +99,18 @@
 
 }  // 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)
@@ -170,25 +182,18 @@
 }
 
 void NodeController::ReservePort(const std::string& token,
-                                 const ports::PortRef& port) {
+                                 const ReservePortCallback& callback) {
+  ports::PortRef port;
+  node_->CreateUninitializedPort(&port);
+
   DVLOG(2) << "Reserving port " << port.name() << "@" << name_ << " for token "
            << token;
 
   base::AutoLock lock(reserved_ports_lock_);
-  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));
+  ReservedPort reservation;
+  reservation.local_port = port;
+  reservation.callback = callback;
+  reserved_ports_.insert(std::make_pair(token, reservation));
 }
 
 scoped_refptr<PlatformSharedBuffer> NodeController::CreateSharedBuffer(
@@ -203,6 +208,42 @@
   }
 #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) {
@@ -263,6 +304,46 @@
   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_);
@@ -332,6 +413,19 @@
   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);
   }
 }
 
@@ -522,8 +616,6 @@
   // 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,
@@ -671,16 +763,15 @@
                                  io_task_runner_);
     AddPeer(broker_name, broker, true /* start_channel */);
   }
-
   AddPeer(parent_name, parent, false /* start_channel */);
 
-  {
-    // 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();
-  }
+  // 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);
+  }
+  pending_port_requests_.clear();
 
   // Feed the broker any pending children of our own.
   while (!pending_broker_clients.empty()) {
@@ -733,15 +824,16 @@
   AttemptShutdownIfRequested();
 }
 
-void NodeController::OnRequestPortMerge(
+void NodeController::OnRequestPortConnection(
     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 RequestPortMerge for token "
+  DVLOG(2) << "Node " << name_ << " received RequestPortConnection for token "
            << token << " and port " << connector_port_name << "@" << from_node;
 
+  ReservePortCallback callback;
   ports::PortRef local_port;
   {
     base::AutoLock lock(reserved_ports_lock_);
@@ -751,12 +843,64 @@
                << token;
       return;
     }
-    local_port = it->second;
-  }
-
-  int rv = node_->MergePorts(local_port, from_node, connector_port_name);
-  if (rv != ports::OK)
-    DLOG(ERROR) << "MergePorts failed: " << rv;
+    local_port = it->second.local_port;
+    callback = it->second.callback;
+    reserved_ports_.erase(it);
+  }
+
+  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);
 }
 
 void NodeController::OnRequestIntroduction(const ports::NodeName& from_node,