blob: 18e554f4422390fdecfb72fe53e61f30c66513e1 [file] [log] [blame]
// Copyright 2021 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
// 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 "pw_polyfill/language_feature_macros.h"
#include "pw_sync/lock_annotations.h"
namespace pw::sync {
// The VirtualBasicLockable is a virtual lock abstraction for locks which meet
// the C++ named BasicLockable requirements of lock() and unlock().
// This virtual indirection is useful in case you need configurable lock
// selection in a portable module where the final type is not defined upstream
// and ergo module configuration cannot be used or in case the lock type is not
// fixed at compile time, for example to support run time and crash time use of
// an object without incurring the code size hit for templating the object.
class PW_LOCKABLE("pw::sync::VirtualBasicLockable") VirtualBasicLockable {
void unlock() PW_UNLOCK_FUNCTION() { DoLockOperation(Operation::kUnlock); }
~VirtualBasicLockable() = default;
enum class Operation {
// Uses a single virtual method with an enum to minimize the vtable cost per
// implementation of VirtualBasicLockable.
virtual void DoLockOperation(Operation operation) = 0;
// The NoOpLock is a type of VirtualBasicLockable that does nothing, i.e. lock
// operations are no-ops.
class PW_LOCKABLE("pw::sync::NoOpLock") NoOpLock final
: public VirtualBasicLockable {
constexpr NoOpLock() {}
NoOpLock(const NoOpLock&) = delete;
NoOpLock(NoOpLock&&) = delete;
NoOpLock& operator=(const NoOpLock&) = delete;
NoOpLock& operator=(NoOpLock&&) = delete;
// Gives access to a global NoOpLock instance. It is not necessary to have
// multiple NoOpLock instances since they have no state and do nothing.
static NoOpLock& Instance() {
PW_CONSTINIT static NoOpLock lock;
return lock;
void DoLockOperation(Operation) override {}
} // namespace pw::sync