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// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MOJO_CORE_MESSAGE_PIPE_DISPATCHER_H_
#define MOJO_CORE_MESSAGE_PIPE_DISPATCHER_H_
#include <stdint.h>
#include <memory>
#include <optional>
#include "base/memory/raw_ptr_exclusion.h"
#include "mojo/core/atomic_flag.h"
#include "mojo/core/dispatcher.h"
#include "mojo/core/ports/port_ref.h"
#include "mojo/core/watcher_set.h"
namespace mojo {
namespace core {
class NodeController;
class MessagePipeDispatcher : public Dispatcher {
public:
// Constructs a MessagePipeDispatcher permanently tied to a specific port.
// |connected| must indicate the state of the port at construction time; if
// the port is initialized with a peer, |connected| must be true. Otherwise it
// must be false.
//
// A MessagePipeDispatcher may not be transferred while in a disconnected
// state, and one can never return to a disconnected once connected.
//
// |pipe_id| is a unique identifier which can be used to track pipe endpoints
// as they're passed around. |endpoint| is either 0 or 1 and again is only
// used for tracking pipes (one side is always 0, the other is always 1.)
MessagePipeDispatcher(NodeController* node_controller,
const ports::PortRef& port,
uint64_t pipe_id,
int endpoint);
MessagePipeDispatcher(const MessagePipeDispatcher&) = delete;
MessagePipeDispatcher& operator=(const MessagePipeDispatcher&) = delete;
// Fuses this pipe with |other|. Returns |true| on success or |false| on
// failure. Regardless of the return value, both dispatchers are closed by
// this call.
bool Fuse(MessagePipeDispatcher* other);
// Dispatcher:
Type GetType() const override;
MojoResult Close() override;
MojoResult WriteMessage(
std::unique_ptr<ports::UserMessageEvent> message) override;
MojoResult ReadMessage(
std::unique_ptr<ports::UserMessageEvent>* message) override;
MojoResult SetQuota(MojoQuotaType type, uint64_t limit) override;
MojoResult QueryQuota(MojoQuotaType type,
uint64_t* limit,
uint64_t* usage) override;
HandleSignalsState GetHandleSignalsState() const override;
MojoResult AddWatcherRef(const scoped_refptr<WatcherDispatcher>& watcher,
uintptr_t context) override;
MojoResult RemoveWatcherRef(WatcherDispatcher* watcher,
uintptr_t context) override;
void StartSerialize(uint32_t* num_bytes,
uint32_t* num_ports,
uint32_t* num_handles) override;
bool EndSerialize(void* destination,
ports::PortName* ports,
PlatformHandle* handles) override;
bool BeginTransit() override;
void CompleteTransitAndClose() override;
void CancelTransit() override;
static scoped_refptr<Dispatcher> Deserialize(const void* data,
size_t num_bytes,
const ports::PortName* ports,
size_t num_ports,
PlatformHandle* handles,
size_t num_handles);
private:
class PortObserverThunk;
friend class PortObserverThunk;
~MessagePipeDispatcher() override;
MojoResult CloseNoLock();
HandleSignalsState GetHandleSignalsStateNoLock() const;
void OnPortStatusChanged();
// These are safe to access from any thread without locking.
// `node_controller_` is not a raw_ptr<...> for performance reasons (based on
// analysis of sampling profiler data).
RAW_PTR_EXCLUSION NodeController* const node_controller_;
const ports::PortRef port_;
const uint64_t pipe_id_;
const int endpoint_;
// Guards access to all the fields below.
mutable base::Lock signal_lock_;
// This is not the same is |port_transferred_|. It's only held true between
// BeginTransit() and Complete/CancelTransit().
AtomicFlag in_transit_;
mutable MojoHandleSignals last_known_satisfied_signals_ = 0;
bool port_transferred_ = false;
AtomicFlag port_closed_;
WatcherSet watchers_;
std::optional<uint64_t> receive_queue_length_limit_;
std::optional<uint64_t> receive_queue_memory_size_limit_;
std::optional<uint64_t> unread_message_count_limit_;
};
} // namespace core
} // namespace mojo
#endif // MOJO_CORE_MESSAGE_PIPE_DISPATCHER_H_
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