69 lines
2.0 KiB
C++
69 lines
2.0 KiB
C++
// Copyright 2021 The Pigweed Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not
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// use this file except in compliance with the License. You may obtain a copy of
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// the License at
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//
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// https://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, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations under
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// the License.
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#include "pw_chrono/system_timer.h"
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#include <thread>
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namespace pw::chrono {
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namespace {
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using CallbackContext = backend::NativeSystemTimer::CallbackContext;
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void SystemTimerThreadFunction(
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std::shared_ptr<bool> timer_enabled,
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std::shared_ptr<CallbackContext> callback_context,
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SystemClock::time_point expiry_deadline) {
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// Sleep until the requested deadline.
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std::this_thread::sleep_until(expiry_deadline);
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{
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std::lock_guard lock(callback_context->mutex);
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// Only invoke the user's callback if this invocation has not been
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// cancelled.
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if (*timer_enabled) {
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(callback_context->callback)(expiry_deadline);
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}
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}
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}
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} // namespace
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void SystemTimer::InvokeAt(SystemClock::time_point timestamp) {
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std::lock_guard lock(native_type_.callback_context->mutex);
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// First, cancel any outstanding requests.
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if (native_type_.active_timer_enabled) {
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*native_type_.active_timer_enabled = false;
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}
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// Second, active another detached timer thread with a new shared atomic bool.
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native_type_.active_timer_enabled = std::make_shared<bool>(true);
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std::thread(SystemTimerThreadFunction,
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native_type_.active_timer_enabled,
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native_type_.callback_context,
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timestamp)
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.detach();
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}
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void SystemTimer::Cancel() {
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std::lock_guard lock(native_type_.callback_context->mutex);
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if (native_type_.active_timer_enabled) {
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*native_type_.active_timer_enabled = false;
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}
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}
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} // namespace pw::chrono
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