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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at */
#ifndef mozilla_ipc_NodeController_h
#define mozilla_ipc_NodeController_h
#include "mojo/core/ports/event.h"
#include "mojo/core/ports/name.h"
#include "mojo/core/ports/node.h"
#include "mojo/core/ports/node_delegate.h"
#include "chrome/common/ipc_message.h"
#include "mozilla/ipc/ProtocolUtils.h"
#include "nsTHashMap.h"
#include "mozilla/Queue.h"
#include "mozilla/DataMutex.h"
#include "mozilla/UniquePtr.h"
#include "mozilla/ipc/NodeChannel.h"
namespace mozilla::ipc {
class GeckoChildProcessHost;
class NodeController final : public mojo::core::ports::NodeDelegate,
public NodeChannel::Listener {
using NodeName = mojo::core::ports::NodeName;
using PortName = mojo::core::ports::PortName;
using PortRef = mojo::core::ports::PortRef;
using Event = mojo::core::ports::Event;
using Node = mojo::core::ports::Node;
using UserData = mojo::core::ports::UserData;
using PortStatus = mojo::core::ports::PortStatus;
using UserMessageEvent = mojo::core::ports::UserMessageEvent;
using UserMessage = mojo::core::ports::UserMessage;
// Return the global singleton instance. The returned value is only valid
// while the IO thread is alive.
static NodeController* GetSingleton();
class PortObserver : public UserData {
virtual void OnPortStatusChanged() = 0;
~PortObserver() override = default;
// NOTE: For now there will always be a single broker process, and all
// processes in the graph need to be able to talk to it (the parent process).
// Give it a fixed node name for now to simplify things.
// If we ever decide to have multiple node networks intercommunicating (e.g.
// multiple instances or background services), we may need to change this.
static constexpr NodeName kBrokerNodeName{0x1, 0x1};
bool IsBroker() const { return mName == kBrokerNodeName; }
// Mint a new connected pair of ports within the current process.
std::pair<ScopedPort, ScopedPort> CreatePortPair();
// Get a reference to the port with the given name. Returns an invalid
// `PortRef` if the name wasn't found.
PortRef GetPort(const PortName& aName);
// Set the observer for the given port. This observer will be notified when
// the status of the port changes.
void SetPortObserver(const PortRef& aPort, PortObserver* aObserver);
// See `mojo::core::ports::Node::GetStatus`
Maybe<PortStatus> GetStatus(const PortRef& aPort);
// See `mojo::core::ports::Node::ClosePort`
void ClosePort(const PortRef& aPort);
// Send a message to the the port's connected peer.
bool SendUserMessage(const PortRef& aPort, UniquePtr<IPC::Message> aMessage);
// Get the next message from the port's message queue.
// Will set `*aMessage` to the found message, or `nullptr`.
// Returns `false` and sets `*aMessage` to `nullptr` if no further messages
// will be delivered to this port as its peer has been closed.
bool GetMessage(const PortRef& aPort, UniquePtr<IPC::Message>* aMessage);
// Called in the broker process from GeckoChildProcessHost to introduce a new
// child process into the network. Returns a `PortRef` which can be used to
// communicate with the `PortRef` returned from `InitChildProcess`, and a
// reference to the `NodeChannel` created for the new process. The port can
// immediately have messages sent to it.
std::tuple<ScopedPort, RefPtr<NodeChannel>> InviteChildProcess(
UniquePtr<IPC::Channel> aChannel,
GeckoChildProcessHost* aChildProcessHost);
// Called as the IO thread is started in the parent process.
static void InitBrokerProcess();
// Called as the IO thread is started in a child process.
static ScopedPort InitChildProcess(UniquePtr<IPC::Channel> aChannel,
base::ProcessId aParentPid);
// Called when the IO thread is torn down.
static void CleanUp();
explicit NodeController(const NodeName& aName);
UniquePtr<IPC::Message> SerializeEventMessage(
UniquePtr<Event> aEvent, const NodeName* aRelayTarget = nullptr,
uint32_t aType = EVENT_MESSAGE_TYPE);
UniquePtr<Event> DeserializeEventMessage(UniquePtr<IPC::Message> aMessage,
NodeName* aRelayTarget = nullptr);
// Get the `NodeChannel` for the named node.
already_AddRefed<NodeChannel> GetNodeChannel(const NodeName& aName);
// Stop communicating with this peer. Must be called on the IO thread.
void DropPeer(NodeName aNodeName);
// Message Handlers
void OnEventMessage(const NodeName& aFromNode,
UniquePtr<IPC::Message> aMessage) override;
void OnBroadcast(const NodeName& aFromNode,
UniquePtr<IPC::Message> aMessage) override;
void OnIntroduce(const NodeName& aFromNode,
NodeChannel::Introduction aIntroduction) override;
void OnRequestIntroduction(const NodeName& aFromNode,
const NodeName& aName) override;
void OnAcceptInvite(const NodeName& aFromNode, const NodeName& aRealName,
const PortName& aInitialPort) override;
void OnChannelError(const NodeName& aFromNode) override;
// NodeDelegate Implementation
void ForwardEvent(const NodeName& aNode, UniquePtr<Event> aEvent) override;
void BroadcastEvent(UniquePtr<Event> aEvent) override;
void PortStatusChanged(const PortRef& aPortRef) override;
const NodeName mName;
const UniquePtr<Node> mNode;
template <class T>
using NodeMap = nsTHashMap<NodeNameHashKey, T>;
struct Invite {
// The channel which is being invited. This will have a temporary name until
// the invite is completed.
RefPtr<NodeChannel> mChannel;
// The port which will be merged with the port information from the new
// child process when recieved.
PortRef mToMerge;
struct State {
// Channels for connecting to all known peers.
NodeMap<RefPtr<NodeChannel>> mPeers;
// Messages which are queued for peers which we been introduced to yet.
NodeMap<Queue<UniquePtr<IPC::Message>, 64>> mPendingMessages;
// Connections for peers being invited to the network.
NodeMap<Invite> mInvites;
// Ports which are waiting to be merged by a particular peer node.
NodeMap<nsTArray<PortRef>> mPendingMerges;
DataMutex<State> mState{"NodeController::mState"};
} // namespace mozilla::ipc