blob: eefbed699d7f70c25059027dde73bdc821cc1212 [file] [log] [blame]
// 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
// 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 <stdbool.h>
#include "pw_preprocessor/util.h"
#include "pw_sync/lock_annotations.h"
#ifdef __cplusplus
#include "pw_sync/virtual_basic_lockable.h"
#include "pw_sync_backend/mutex_native.h"
namespace pw::sync {
// The Mutex is a synchronization primitive that can be used to protect
// shared data from being simultaneously accessed by multiple threads.
// It offers exclusive, non-recursive ownership semantics where priority
// inheritance is used to solve the classic priority-inversion problem.
// This is thread safe, but NOT IRQ safe.
// WARNING: In order to support global statically constructed Mutexes, the user
// and/or backend MUST ensure that any initialization required in your
// environment is done prior to the creation and/or initialization of the native
// synchronization primitives (e.g. kernel initialization).
class PW_LOCKABLE("pw::sync::Mutex") Mutex {
using native_handle_type = backend::NativeMutexHandle;
Mutex(const Mutex&) = delete;
Mutex(Mutex&&) = delete;
Mutex& operator=(const Mutex&) = delete;
Mutex& operator=(Mutex&&) = delete;
// Locks the mutex, blocking indefinitely. Failures are fatal.
// The lock isn't already held by this thread. Recursive locking is
// undefined behavior.
// Attempts to lock the mutex in a non-blocking manner.
// Returns true if the mutex was successfully acquired.
// The lock isn't already held by this thread. Recursive locking is
// undefined behavior.
bool try_lock() PW_EXCLUSIVE_TRYLOCK_FUNCTION(true);
// Unlocks the mutex. Failures are fatal.
// The mutex is held by this thread.
void unlock() PW_UNLOCK_FUNCTION();
native_handle_type native_handle();
// Expose the NativeMutex directly to derived classes (TimedMutex) in
// case implementations use different types for backend::NativeMutex and
// native_handle().
backend::NativeMutex& native_type() { return native_type_; }
const backend::NativeMutex& native_type() const { return native_type_; }
// This may be a wrapper around a native type with additional members.
backend::NativeMutex native_type_;
class PW_LOCKABLE("pw::sync::VirtualMutex") VirtualMutex final
: public VirtualBasicLockable {
VirtualMutex() = default;
VirtualMutex(const VirtualMutex&) = delete;
VirtualMutex(VirtualMutex&&) = delete;
VirtualMutex& operator=(const VirtualMutex&) = delete;
VirtualMutex& operator=(VirtualMutex&&) = delete;
Mutex& mutex() { return mutex_; }
void DoLockOperation(Operation operation) override
switch (operation) {
case Operation::kLock:
return mutex_.lock();
case Operation::kUnlock:
return mutex_.unlock();
Mutex mutex_;
} // namespace pw::sync
#include "pw_sync_backend/mutex_inline.h"
using pw_sync_Mutex = pw::sync::Mutex;
#else // !defined(__cplusplus)
typedef struct pw_sync_Mutex pw_sync_Mutex;
#endif // __cplusplus
void pw_sync_Mutex_Lock(pw_sync_Mutex* mutex) PW_NO_LOCK_SAFETY_ANALYSIS;
bool pw_sync_Mutex_TryLock(pw_sync_Mutex* mutex) PW_NO_LOCK_SAFETY_ANALYSIS;
void pw_sync_Mutex_Unlock(pw_sync_Mutex* mutex) PW_NO_LOCK_SAFETY_ANALYSIS;