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/*
*
* Copyright (c) 2020-2021 Project CHIP Authors
* Copyright (c) 2016-2017 Nest Labs, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file
* This file contains declarations of the
* chip::System::Layer class and its related types, data and
* functions.
*/
#pragma once
// Include configuration headers
#include <system/SystemConfig.h>
#include <lib/core/CHIPCallback.h>
#include <lib/support/CodeUtils.h>
#include <lib/support/DLLUtil.h>
#include <lib/support/LambdaBridge.h>
#include <system/SystemClock.h>
#include <system/SystemError.h>
#include <system/SystemEvent.h>
#if CHIP_SYSTEM_CONFIG_USE_SOCKETS
#include <system/SocketEvents.h>
#endif // CHIP_SYSTEM_CONFIG_USE_SOCKETS
#if CHIP_SYSTEM_CONFIG_USE_DISPATCH
#include <dispatch/dispatch.h>
#endif // CHIP_SYSTEM_CONFIG_USE_DISPATCH
#include <utility>
namespace chip {
namespace System {
class Layer;
using TimerCompleteCallback = void (*)(Layer * aLayer, void * appState);
/**
* This provides access to timers according to the configured event handling model.
*
* The abstract class hierarchy is:
* - Layer: Core timer methods.
* - LayerLwIP: Adds methods specific to CHIP_SYSTEM_CONFIG_USING_LWIP.
* - LayerSockets: Adds I/O event methods specific to CHIP_SYSTEM_CONFIG_USING_SOCKETS.
* - LayerSocketsLoop: Adds methods for event-loop-based implementations.
*
* Threading notes:
*
* The SDK is not generally thread safe. System::Layer methods should only be called from
* a single context, or otherwise externally synchronized. For platforms that use a CHIP
* event loop thread, timer callbacks are invoked on that thread; for platforms that use
* a CHIP lock, the lock is held.
*/
class DLL_EXPORT Layer
{
public:
Layer() = default;
virtual ~Layer() = default;
/**
* Initialize the Layer.
*/
virtual CHIP_ERROR Init() = 0;
/**
* Shut down the Layer.
*
* Some other layers hold pointers to System::Layer, so care must be taken
* to ensure that they are not used after calling Shutdown().
*/
virtual CHIP_ERROR Shutdown() = 0;
/**
* True if this Layer is initialized. No method on Layer or its abstract descendants, other than this and `Init()`,
* may be called from general code unless this is true. (Individual Impls may have looser constraints internally.)
*/
virtual bool IsInitialized() const = 0;
/**
* @brief
* This method starts a one-shot timer.
*
* @note
* Only a single timer is allowed to be started with the same @a aComplete and @a aAppState
* arguments. If called with @a aComplete and @a aAppState identical to an existing timer,
* the currently-running timer will first be cancelled.
*
* @param[in] aDelay Time before this timer fires.
* @param[in] aComplete A pointer to the function called when timer expires.
* @param[in] aAppState A pointer to the application state object used when timer expires.
*
* @return CHIP_NO_ERROR On success.
* @return CHIP_ERROR_NO_MEMORY If a timer cannot be allocated.
* @return Other Value indicating timer failed to start.
*/
virtual CHIP_ERROR StartTimer(Clock::Timeout aDelay, TimerCompleteCallback aComplete, void * aAppState) = 0;
/**
* @brief
* This method cancels a one-shot timer, started earlier through @p StartTimer().
*
* @note
* The cancellation could fail silently in two different ways. If the timer specified by the combination of the callback
* function and application state object couldn't be found, cancellation could fail. If the timer has fired, but not yet
* removed from memory, cancellation could also fail.
*
* @param[in] aOnComplete A pointer to the callback function used in calling @p StartTimer().
* @param[in] aAppState A pointer to the application state object used in calling @p StartTimer().
*
*/
virtual void CancelTimer(TimerCompleteCallback aOnComplete, void * aAppState) = 0;
/**
* @brief
* Schedules a function with a signature identical to `OnCompleteFunct` to be run as soon as possible in the CHIP context.
*
* @param[in] aComplete A pointer to a callback function to be called when this timer fires.
* @param[in] aAppState A pointer to an application state object to be passed to the callback function as argument.
*
* @retval CHIP_ERROR_INCORRECT_STATE If the System::Layer has not been initialized.
* @retval CHIP_ERROR_NO_MEMORY If the SystemLayer cannot allocate a new timer.
* @retval CHIP_NO_ERROR On success.
*/
virtual CHIP_ERROR ScheduleWork(TimerCompleteCallback aComplete, void * aAppState) = 0;
/**
* @brief
* Schedules a lambda even to be run as soon as possible in the CHIP context. This function is not thread-safe,
* it must be called with in the CHIP context
*
* @param[in] event A object encapsulate the context of a lambda
*
* @retval CHIP_NO_ERROR On success.
* @retval other Platform-specific errors generated indicating the reason for failure.
*/
CHIP_ERROR ScheduleLambdaBridge(LambdaBridge && event);
/**
* @brief
* Schedules a lambda object to be run as soon as possible in the CHIP context. This function is not thread-safe,
* it must be called with in the CHIP context
*/
template <typename Lambda>
CHIP_ERROR ScheduleLambda(const Lambda & lambda)
{
LambdaBridge bridge;
bridge.Initialize(lambda);
return ScheduleLambdaBridge(std::move(bridge));
}
private:
// Copy and assignment NOT DEFINED
Layer(const Layer &) = delete;
Layer & operator=(const Layer &) = delete;
};
#if CHIP_SYSTEM_CONFIG_USE_LWIP
class LayerLwIP : public Layer
{
};
#endif // CHIP_SYSTEM_CONFIG_USE_LWIP
#if CHIP_SYSTEM_CONFIG_USE_SOCKETS
class LayerSockets : public Layer
{
public:
/**
* Initialize watching for events on a file descriptor.
*
* Returns an opaque token through @a tokenOut that must be passed to subsequent operations for this file descriptor.
* StopWatchingSocket() must be called before closing the file descriptor.
*/
virtual CHIP_ERROR StartWatchingSocket(int fd, SocketWatchToken * tokenOut) = 0;
/**
* Register a callback function.
*
* The callback will be invoked (with the CHIP stack lock held) when requested event(s) are ready.
*/
virtual CHIP_ERROR SetCallback(SocketWatchToken token, SocketWatchCallback callback, intptr_t data) = 0;
/**
* Request a callback when the associated file descriptor is readable.
*/
virtual CHIP_ERROR RequestCallbackOnPendingRead(SocketWatchToken token) = 0;
/**
* Request a callback when the associated file descriptor is writable.
*/
virtual CHIP_ERROR RequestCallbackOnPendingWrite(SocketWatchToken token) = 0;
/**
* Cancel a request for a callback when the associated file descriptor is readable.
*/
virtual CHIP_ERROR ClearCallbackOnPendingRead(SocketWatchToken token) = 0;
/**
* Cancel a request for a callback when the associated file descriptor is writable.
*/
virtual CHIP_ERROR ClearCallbackOnPendingWrite(SocketWatchToken token) = 0;
/**
* Stop watching for events on the associated file descriptor.
*
* This MUST be called before the file descriptor is closed.
* It is not necessary to clear callback requests before calling this function.
*/
virtual CHIP_ERROR StopWatchingSocket(SocketWatchToken * tokenInOut) = 0;
/**
* Return a SocketWatchToken that is guaranteed not to be valid. Clients may use this to initialize variables.
*/
virtual SocketWatchToken InvalidSocketWatchToken() = 0;
};
class LayerSocketsLoop : public LayerSockets
{
public:
virtual void Signal() = 0;
virtual void EventLoopBegins() = 0;
virtual void PrepareEvents() = 0;
virtual void WaitForEvents() = 0;
virtual void HandleEvents() = 0;
virtual void EventLoopEnds() = 0;
#if CHIP_SYSTEM_CONFIG_USE_DISPATCH
virtual void SetDispatchQueue(dispatch_queue_t dispatchQueue) = 0;
virtual dispatch_queue_t GetDispatchQueue() = 0;
#endif // CHIP_SYSTEM_CONFIG_USE_DISPATCH
};
#endif // CHIP_SYSTEM_CONFIG_USE_SOCKETS
} // namespace System
} // namespace chip