1 // Copyright 2020 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 15 #include "pw_sync/binary_semaphore.h" 16 17 #include "pw_assert/check.h" 18 19 using pw::chrono::SystemClock; 20 21 namespace pw::sync { 22 release()23void BinarySemaphore::release() { 24 std::lock_guard lock(native_type_.mutex); 25 PW_DCHECK_UINT_LT(native_type_.count, BinarySemaphore::max()); 26 ++native_type_.count; 27 native_type_.condition.notify_one(); 28 } 29 acquire()30void BinarySemaphore::acquire() { 31 std::unique_lock lock(native_type_.mutex); 32 native_type_.condition.wait(lock, [&] { return native_type_.count != 0; }); 33 native_type_.count = 0; 34 } 35 try_acquire()36bool BinarySemaphore::try_acquire() noexcept { 37 std::lock_guard lock(native_type_.mutex); 38 if (native_type_.count != 0) { 39 native_type_.count = 0; 40 return true; 41 } 42 return false; 43 } 44 try_acquire_until(SystemClock::time_point deadline)45bool BinarySemaphore::try_acquire_until(SystemClock::time_point deadline) { 46 std::unique_lock lock(native_type_.mutex); 47 if (native_type_.condition.wait_until( 48 lock, deadline, [&] { return native_type_.count != 0; })) { 49 native_type_.count = 0; 50 return true; 51 } 52 return false; 53 } 54 55 } // namespace pw::sync 56