blob: 9f2937ddbb6784663c134114ad3f9e42ccd6d58f [file] [log] [blame] [edit]
// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <lib/async/cpp/task.h>
#include <lib/async/cpp/time.h>
#include <zircon/assert.h>
#include <utility>
namespace async {
namespace internal {
struct RetainedTask : public async_task_t {
RetainedTask(fit::closure handler, zx::time deadline)
: async_task_t{{ASYNC_STATE_INIT}, &RetainedTask::Handler, deadline.get()},
handler(static_cast<fit::closure&&>(handler)) {}
fit::closure handler;
static void Handler(async_dispatcher_t* dispatcher, async_task_t* task, zx_status_t status) {
auto self = static_cast<RetainedTask*>(task);
if (status == ZX_OK)
self->handler();
delete self;
}
};
} // namespace internal
zx_status_t PostTask(async_dispatcher_t* dispatcher, fit::closure handler) {
return PostTaskForTime(dispatcher, static_cast<fit::closure&&>(handler), async::Now(dispatcher));
}
zx_status_t PostDelayedTask(async_dispatcher_t* dispatcher, fit::closure handler,
zx::duration delay) {
return PostTaskForTime(dispatcher, static_cast<fit::closure&&>(handler),
async::Now(dispatcher) + delay);
}
zx_status_t PostTaskForTime(async_dispatcher_t* dispatcher, fit::closure handler,
zx::time deadline) {
auto* task = new internal::RetainedTask(static_cast<fit::closure&&>(handler), deadline);
zx_status_t status = async_post_task(dispatcher, task);
if (status != ZX_OK)
delete task;
return status;
}
TaskBase::TaskBase(async_task_handler_t* handler)
: task_{{ASYNC_STATE_INIT}, handler, ZX_TIME_INFINITE} {}
TaskBase::~TaskBase() {
if (dispatcher_) {
// Failure to cancel here may result in a dangling pointer...
zx_status_t status = async_cancel_task(dispatcher_, &task_);
ZX_ASSERT_MSG(status == ZX_OK, "status=%d", status);
}
}
zx_status_t TaskBase::Post(async_dispatcher_t* dispatcher) {
return PostForTime(dispatcher, async::Now(dispatcher));
}
zx_status_t TaskBase::PostDelayed(async_dispatcher_t* dispatcher, zx::duration delay) {
return PostForTime(dispatcher, async::Now(dispatcher) + delay);
}
zx_status_t TaskBase::PostForTime(async_dispatcher_t* dispatcher, zx::time deadline) {
if (dispatcher_)
return ZX_ERR_ALREADY_EXISTS;
dispatcher_ = dispatcher;
task_.deadline = deadline.get();
zx_status_t status = async_post_task(dispatcher, &task_);
if (status != ZX_OK) {
dispatcher_ = nullptr;
}
return status;
}
zx_status_t TaskBase::Cancel() {
if (!dispatcher_)
return ZX_ERR_NOT_FOUND;
async_dispatcher_t* dispatcher = dispatcher_;
dispatcher_ = nullptr;
zx_status_t status = async_cancel_task(dispatcher, &task_);
// |dispatcher| is required to be single-threaded, Cancel() is
// only supposed to be called on |dispatcher|'s thread, and we
// verified that the task was pending before calling
// async_cancel_task(). Assuming that |dispatcher| does not yield
// between removing the task and invoking the task's handler,
// |task_| must have been pending with |dispatcher|.
ZX_DEBUG_ASSERT(status != ZX_ERR_NOT_FOUND);
return status;
}
Task::Task(Handler handler) : TaskBase(&Task::CallHandler), handler_(std::move(handler)) {}
Task::~Task() = default;
void Task::CallHandler(async_dispatcher_t* dispatcher, async_task_t* task, zx_status_t status) {
auto self = Dispatch<Task>(task);
self->handler_(dispatcher, self, status);
}
TaskClosure::TaskClosure(fit::closure handler)
: TaskBase(&TaskClosure::CallHandler), handler_(std::move(handler)) {}
TaskClosure::~TaskClosure() = default;
void TaskClosure::CallHandler(async_dispatcher_t* dispatcher, async_task_t* task,
zx_status_t status) {
auto self = Dispatch<TaskClosure>(task); // must do this if status is not ok
if (status == ZX_OK) {
self->handler_();
}
}
} // namespace async