mirror of https://github.com/ARMmbed/mbed-os.git
169 lines
3.7 KiB
C++
169 lines
3.7 KiB
C++
/*
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* Copyright (c) 2018-2019, Arm Limited and affiliates.
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef TASK_BASE_H
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#define TASK_BASE_H
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#include "platform/Callback.h"
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#include "platform/mbed_assert.h"
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#include "LinkEntry.h"
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namespace rtos {
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class Semaphore;
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}
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namespace events {
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class TaskQueue;
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/**
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* \defgroup drivers_TaskBase TaskBase class
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* \ingroup drivers-internal-api-usb
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* @{
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*/
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/** TaskBase
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*
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* Representation of a caller allocated task
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*/
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class TaskBase : public LinkEntry {
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public:
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typedef void (*run_callback_t)(void *data);
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/**
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* Construct a new TaskBase object
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*
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* @param q Queue for posting to
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*/
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TaskBase(TaskQueue *q);
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/**
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* Destroy this TaskBase
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*/
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virtual ~TaskBase();
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/**
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* Set the queue of this task
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*
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* @param q TaskQueue to post to
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*/
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void set(TaskQueue *q);
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/**
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* Cancel the execution of this task
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*
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* Once cancelled the task can be posted again. Previous
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* calls to post may still run. If you need to ensure the
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* callback has finished the function wait() can be used.
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*
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* @note This function is interrupt safe
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*/
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void cancel();
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/**
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* Return true if this task is ready to be posted
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*
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* Check if this task is on a queue waiting to be run.
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*
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* @return true if it is safe to call post
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*/
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bool ready();
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/**
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* Wait for this task to finish execution
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*
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* When this function returns then this task is in the finished state.
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*/
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void wait();
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/**
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* Check if the callback has run to completion or been fully canceled
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*
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* When an task is finished the queue is completely done with it and the
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* callback is either fully complete or has been canceled and will not run.
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*
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* @return true if this task has been flushed from the queue, false otherwise
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*/
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bool finished();
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protected:
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/**
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* Size of buffer required for TaskBase::start
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*
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* @return requested buffer size
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*/
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virtual uint32_t size() = 0;
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/**
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* Copy any callback data and return a callback to run
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*
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* @param data Buffer to copy data to. Do not copy more than TaskBase::size() data.
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* @param size Maximum size to copy
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*/
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virtual run_callback_t start(void *data, uint32_t size) = 0;
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/**
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* Inform this task that execution has finished.
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*
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*/
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virtual void finish();
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/**
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* Post this task to the set TaskQueue for execution
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*/
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void post();
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private:
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TaskQueue *_queue;
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bool _posted;
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uint16_t _start_count;
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rtos::Semaphore *_flush_sem;
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friend class TaskQueue;
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/*
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* Must be called in a critical section
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*
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* This function should not be called directly. Instead
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* TaskQueue::task_start should be used instead.
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*/
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run_callback_t _start(void *buffer, uint32_t size);
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/*
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* Must be called in a critical section
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*
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* This function should not be called directly. Instead
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* TaskQueue::task_finish should be used instead.
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*
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*/
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void _finish();
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/*
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* Unblock wait if this task is finished
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*/
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void _wake_check();
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};
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/** @}*/
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}
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#endif
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