mirror of https://github.com/ARMmbed/mbed-os.git
106 lines
2.6 KiB
C
106 lines
2.6 KiB
C
|
/* mbed Microcontroller Library
|
||
|
|
* Copyright (c) 2006-2013 ARM Limited
|
||
|
|
*
|
||
|
|
* 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
|
||
|
|
*
|
||
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
||
|
|
*
|
||
|
|
* 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.
|
||
|
|
*/
|
||
|
|
#ifndef SINGLETONPTR_H
|
||
|
|
#define SINGLETONPTR_H
|
||
|
|
|
||
|
|
#include <stdint.h>
|
||
|
|
#include <new>
|
||
|
|
#include "mbed_assert.h"
|
||
|
|
#ifdef MBED_CONF_RTOS_PRESENT
|
||
|
|
#include "cmsis_os.h"
|
||
|
|
#endif
|
||
|
|
|
||
|
|
#ifdef MBED_CONF_RTOS_PRESENT
|
||
|
|
extern osMutexId singleton_mutex_id;
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/** Lock the singleton mutex
|
||
|
|
*
|
||
|
|
* This function is typically used to provide
|
||
|
|
* exclusive access when initializing a
|
||
|
|
* global object.
|
||
|
|
*/
|
||
|
|
inline static void singleton_lock(void)
|
||
|
|
{
|
||
|
|
#ifdef MBED_CONF_RTOS_PRESENT
|
||
|
|
osMutexWait(singleton_mutex_id, osWaitForever);
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
/** Unlock the singleton mutex
|
||
|
|
*
|
||
|
|
* This function is typically used to provide
|
||
|
|
* exclusive access when initializing a
|
||
|
|
* global object.
|
||
|
|
*/
|
||
|
|
inline static void singleton_unlock(void)
|
||
|
|
{
|
||
|
|
#ifdef MBED_CONF_RTOS_PRESENT
|
||
|
|
osMutexRelease (singleton_mutex_id);
|
||
|
|
#endif
|
||
|
|
}
|
||
|
|
|
||
|
|
/** Utility class for creating an using a singleton
|
||
|
|
*
|
||
|
|
* @Note Synchronization level: Thread safe
|
||
|
|
*
|
||
|
|
* @Note: This class must only be used in a static context -
|
||
|
|
* this class must never be allocated or created on the
|
||
|
|
* stack.
|
||
|
|
*
|
||
|
|
* @Note: This class is lazily initialized on first use.
|
||
|
|
* This class is a POD type so if it is not used it will
|
||
|
|
* be garbage collected.
|
||
|
|
*/
|
||
|
|
template <class T>
|
||
|
|
struct SingletonPtr {
|
||
|
|
|
||
|
|
/** Get a pointer to the underlying singleton
|
||
|
|
*
|
||
|
|
* @returns
|
||
|
|
* A pointer to the singleton
|
||
|
|
*/
|
||
|
|
T* get() {
|
||
|
|
if (NULL == _ptr) {
|
||
|
|
singleton_lock();
|
||
|
|
if (NULL == _ptr) {
|
||
|
|
_ptr = new (_data) T();
|
||
|
|
}
|
||
|
|
singleton_unlock();
|
||
|
|
}
|
||
|
|
// _ptr was not zero initialized or was
|
||
|
|
// corrupted if this assert is hit
|
||
|
|
MBED_ASSERT(_ptr == (T *)&_data);
|
||
|
|
return _ptr;
|
||
|
|
}
|
||
|
|
|
||
|
|
/** Get a pointer to the underlying singleton
|
||
|
|
*
|
||
|
|
* @returns
|
||
|
|
* A pointer to the singleton
|
||
|
|
*/
|
||
|
|
T* operator->() {
|
||
|
|
return get();
|
||
|
|
}
|
||
|
|
|
||
|
|
// This is zero initialized when in global scope
|
||
|
|
T *_ptr;
|
||
|
|
// Force data to be 4 byte aligned
|
||
|
|
uint32_t _data[(sizeof(T) + sizeof(uint32_t) - 1) / sizeof(uint32_t)];
|
||
|
|
};
|
||
|
|
|
||
|
|
#endif
|