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// Copyright 2020 The Pigweed Authors
//
// 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
//
// https://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.
#pragma once
#include <cstdint>
#include <span>
#include "FreeRTOS.h"
#include "pw_thread_freertos/config.h"
#include "task.h"
#if PW_THREAD_JOINING_ENABLED
#include "event_groups.h"
#endif // PW_THREAD_JOINING_ENABLED
namespace pw::thread {
class Thread; // Forward declare Thread which depends on Context.
} // namespace pw::thread
namespace pw::thread::freertos {
// FreeRTOS may be used for dynamic thread TCB and stack allocation, but
// because we need some additional context beyond that the concept of a
// thread's context is split into two halves:
//
// 1) Context which just contains the additional Context pw::thread::Thread
// requires. This is used for both static and dynamic thread allocations.
//
// 2) StaticContext which contains the TCB and a span to the stack which is
// used only for static allocations.
class Context {
public:
Context() = default;
Context(const Context&) = delete;
Context& operator=(const Context&) = delete;
private:
friend Thread;
TaskHandle_t task_handle() const { return task_handle_; }
void set_task_handle(const TaskHandle_t task_handle) {
task_handle_ = task_handle;
}
using ThreadRoutine = void (*)(void* arg);
void set_thread_routine(ThreadRoutine entry, void* arg) {
entry_ = entry;
arg_ = arg;
}
bool detached() const { return detached_; }
void set_detached(bool value = true) { detached_ = value; }
bool thread_done() const { return thread_done_; }
void set_thread_done(bool value = true) { thread_done_ = value; }
#if PW_THREAD_FREERTOS_CONFIG_DYNAMIC_ALLOCATION_ENABLED
bool dynamically_allocated() const { return dynamically_allocated_; }
void set_dynamically_allocated() { dynamically_allocated_ = true; }
#endif // PW_THREAD_FREERTOS_CONFIG_DYNAMIC_ALLOCATION_ENABLED
#if PW_THREAD_JOINING_ENABLED
StaticEventGroup_t& join_event_group() { return event_group_; }
#endif // PW_THREAD_JOINING_ENABLED
static void RunThread(void* void_context_ptr);
static void TerminateThread(Context& context);
TaskHandle_t task_handle_ = nullptr;
ThreadRoutine entry_ = nullptr;
void* arg_ = nullptr;
#if PW_THREAD_JOINING_ENABLED
// Note that the FreeRTOS life cycle of this event group is managed together
// with the task life cycle, not this object's life cycle.
StaticEventGroup_t event_group_;
#endif // PW_THREAD_JOINING_ENABLED
bool detached_ = false;
bool dynamically_allocated_ = false;
bool thread_done_ = false;
};
// Static thread context allocation including the TCB, an event group for
// joining if enabled, and an external statically allocated stack.
//
// Example usage:
//
// std::array<StackType_t, 42> example_thread_stack;
// pw::thread::freertos::Context example_thread_context(example_thread_stack);
// void StartExampleThread() {
// pw::thread::Thread(
// pw::thread::freertos::Options()
// .set_name("static_example_thread")
// .set_priority(kFooPriority)
// .set_static_context(example_thread_context),
// example_thread_function).detach();
// }
class StaticContext : public Context {
public:
explicit StaticContext(std::span<StackType_t> stack_span)
: tcb_{}, stack_span_(stack_span) {}
private:
friend Thread;
StaticTask_t& tcb() { return tcb_; }
std::span<StackType_t> stack() { return stack_span_; }
StaticTask_t tcb_;
std::span<StackType_t> stack_span_;
};
// Static thread context allocation including the stack along with the Context.
//
// Example usage:
//
// pw::thread::freertos::ContextWithStack<42> example_thread_context;
// void StartExampleThread() {
// pw::thread::Thread(
// pw::thread::freertos::Options()
// .set_name("static_example_thread")
// .set_priority(kFooPriority)
// .set_static_context(example_thread_context),
// example_thread_function).detach();
// }
template <size_t kStackSizeWords = config::kDefaultStackSizeWords>
class StaticContextWithStack final : public StaticContext {
public:
constexpr StaticContextWithStack() : StaticContext(stack_storage_) {
static_assert(kStackSizeWords >= config::kMinimumStackSizeWords);
}
private:
std::array<StackType_t, kStackSizeWords> stack_storage_;
};
} // namespace pw::thread::freertos
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