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// Copyright (c) 2019 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.
#ifndef PLATFORM_IMPL_PLATFORM_CLIENT_POSIX_H_
#define PLATFORM_IMPL_PLATFORM_CLIENT_POSIX_H_
#include <atomic>
#include <memory>
#include <mutex>
#include <thread>
#include <vector>
#include "absl/types/optional.h"
#include "platform/api/time.h"
#include "platform/base/macros.h"
#include "platform/impl/socket_handle_waiter_posix.h"
#include "platform/impl/task_runner.h"
#include "platform/impl/tls_data_router_posix.h"
namespace openscreen {
class UdpSocketReaderPosix;
// Creates and provides access to singletons used by the default platform
// implementation. An instance must be created before an application uses any
// public modules in the Open Screen Library.
//
// ShutDown() should be called to destroy the PlatformClientPosix's singletons
// and TaskRunner to save resources when library APIs are not in use.
// ShutDown() calls TaskRunner::RunUntilStopped() to run any pending cleanup
// tasks.
//
// Create and ShutDown must be called in the same sequence.
//
// FIXME: Remove Create and Shutdown and use the ctor/dtor directly.
class PlatformClientPosix {
public:
// Initializes the platform implementation.
//
// |networking_loop_interval| sets the minimum amount of time that should pass
// between iterations of the loop used to handle networking operations. Higher
// values will result in less time being spent on these operations, but also
// less performant networking operations. Be careful setting values larger
// than a few hundred microseconds.
//
// |networking_operation_timeout| sets how much time may be spent on a
// single networking operation type.
//
// |task_runner| is a client-provided TaskRunner implementation.
static void Create(Clock::duration networking_operation_timeout,
std::unique_ptr<TaskRunnerImpl> task_runner);
// Initializes the platform implementation and creates a new TaskRunner (which
// starts a new thread).
static void Create(Clock::duration networking_operation_timeout);
// Shuts down and deletes the PlatformClient instance currently stored as a
// singleton. This method is expected to be called before program exit. After
// calling this method, if the client wishes to continue using the platform
// library, Create() must be called again.
static void ShutDown();
static PlatformClientPosix* GetInstance() { return instance_; }
// This method is thread-safe.
// FIXME: Rename to GetTlsDataRouter()
TlsDataRouterPosix* tls_data_router();
// This method is thread-safe.
// FIXME: Rename to GetUdpSocketReader()
UdpSocketReaderPosix* udp_socket_reader();
// Returns the TaskRunner associated with this PlatformClient.
// NOTE: This method is expected to be thread safe.
TaskRunner* GetTaskRunner();
protected:
// Called by ShutDown().
~PlatformClientPosix();
static void SetInstance(PlatformClientPosix* client);
private:
explicit PlatformClientPosix(Clock::duration networking_operation_timeout);
PlatformClientPosix(Clock::duration networking_operation_timeout,
std::unique_ptr<TaskRunnerImpl> task_runner);
// This method is thread-safe.
SocketHandleWaiterPosix* socket_handle_waiter();
void RunNetworkLoopUntilStopped();
std::unique_ptr<TaskRunnerImpl> task_runner_;
// Track whether the associated instance variable has been created yet.
std::atomic_bool waiter_created_{false};
std::atomic_bool tls_data_router_created_{false};
// Parameters for networking loop.
std::atomic_bool networking_loop_running_{true};
Clock::duration networking_loop_timeout_;
// Flags used to ensure that initialization of below instance objects occurs
// only once across all threads.
std::once_flag waiter_initialization_;
std::once_flag udp_socket_reader_initialization_;
std::once_flag tls_data_router_initialization_;
// Instance objects are created at runtime when they are first needed.
std::unique_ptr<SocketHandleWaiterPosix> waiter_;
std::unique_ptr<UdpSocketReaderPosix> udp_socket_reader_;
std::unique_ptr<TlsDataRouterPosix> tls_data_router_;
// Threads for running TaskRunner and OperationLoop instances.
// NOTE: These must be declared last to avoid nondterministic failures.
std::thread networking_loop_thread_;
absl::optional<std::thread> task_runner_thread_;
static PlatformClientPosix* instance_;
OSP_DISALLOW_COPY_AND_ASSIGN(PlatformClientPosix);
};
} // namespace openscreen
#endif // PLATFORM_IMPL_PLATFORM_CLIENT_POSIX_H_