Takaaki Numai / mbed-dev

inport from local

Dependents:   Hobbyking_Cheetah_0511

platform/SingletonPtr.h@0:85b3fd62ea1a, 2020-03-16 (annotated)

Committer:
NYX
Date:
Mon Mar 16 06:35:48 2020 +0000
Revision:
0:85b3fd62ea1a
reinport to mbed;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
NYX 0:85b3fd62ea1a 1
NYX 0:85b3fd62ea1a 2 /** \addtogroup platform */
NYX 0:85b3fd62ea1a 3 /** @{*/
NYX 0:85b3fd62ea1a 4 /* mbed Microcontroller Library
NYX 0:85b3fd62ea1a 5 * Copyright (c) 2006-2013 ARM Limited
NYX 0:85b3fd62ea1a 6 *
NYX 0:85b3fd62ea1a 7 * Licensed under the Apache License, Version 2.0 (the "License");
NYX 0:85b3fd62ea1a 8 * you may not use this file except in compliance with the License.
NYX 0:85b3fd62ea1a 9 * You may obtain a copy of the License at
NYX 0:85b3fd62ea1a 10 *
NYX 0:85b3fd62ea1a 11 * http://www.apache.org/licenses/LICENSE-2.0
NYX 0:85b3fd62ea1a 12 *
NYX 0:85b3fd62ea1a 13 * Unless required by applicable law or agreed to in writing, software
NYX 0:85b3fd62ea1a 14 * distributed under the License is distributed on an "AS IS" BASIS,
NYX 0:85b3fd62ea1a 15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
NYX 0:85b3fd62ea1a 16 * See the License for the specific language governing permissions and
NYX 0:85b3fd62ea1a 17 * limitations under the License.
NYX 0:85b3fd62ea1a 18 */
NYX 0:85b3fd62ea1a 19 #ifndef SINGLETONPTR_H
NYX 0:85b3fd62ea1a 20 #define SINGLETONPTR_H
NYX 0:85b3fd62ea1a 21
NYX 0:85b3fd62ea1a 22 #include <stdint.h>
NYX 0:85b3fd62ea1a 23 #include <new>
NYX 0:85b3fd62ea1a 24 #include "platform/mbed_assert.h"
NYX 0:85b3fd62ea1a 25 #ifdef MBED_CONF_RTOS_PRESENT
NYX 0:85b3fd62ea1a 26 #include "cmsis_os2.h"
NYX 0:85b3fd62ea1a 27 #endif
NYX 0:85b3fd62ea1a 28
NYX 0:85b3fd62ea1a 29 #ifdef MBED_CONF_RTOS_PRESENT
NYX 0:85b3fd62ea1a 30 extern osMutexId_t singleton_mutex_id;
NYX 0:85b3fd62ea1a 31 #endif
NYX 0:85b3fd62ea1a 32
NYX 0:85b3fd62ea1a 33 /** Lock the singleton mutex
NYX 0:85b3fd62ea1a 34 *
NYX 0:85b3fd62ea1a 35 * This function is typically used to provide
NYX 0:85b3fd62ea1a 36 * exclusive access when initializing a
NYX 0:85b3fd62ea1a 37 * global object.
NYX 0:85b3fd62ea1a 38 */
NYX 0:85b3fd62ea1a 39 inline static void singleton_lock(void)
NYX 0:85b3fd62ea1a 40 {
NYX 0:85b3fd62ea1a 41 #ifdef MBED_CONF_RTOS_PRESENT
NYX 0:85b3fd62ea1a 42 osMutexAcquire(singleton_mutex_id, osWaitForever);
NYX 0:85b3fd62ea1a 43 #endif
NYX 0:85b3fd62ea1a 44 }
NYX 0:85b3fd62ea1a 45
NYX 0:85b3fd62ea1a 46 /** Unlock the singleton mutex
NYX 0:85b3fd62ea1a 47 *
NYX 0:85b3fd62ea1a 48 * This function is typically used to provide
NYX 0:85b3fd62ea1a 49 * exclusive access when initializing a
NYX 0:85b3fd62ea1a 50 * global object.
NYX 0:85b3fd62ea1a 51 */
NYX 0:85b3fd62ea1a 52 inline static void singleton_unlock(void)
NYX 0:85b3fd62ea1a 53 {
NYX 0:85b3fd62ea1a 54 #ifdef MBED_CONF_RTOS_PRESENT
NYX 0:85b3fd62ea1a 55 osMutexRelease (singleton_mutex_id);
NYX 0:85b3fd62ea1a 56 #endif
NYX 0:85b3fd62ea1a 57 }
NYX 0:85b3fd62ea1a 58 /** @}*/
NYX 0:85b3fd62ea1a 59
NYX 0:85b3fd62ea1a 60 /** Utility class for creating an using a singleton
NYX 0:85b3fd62ea1a 61 *
NYX 0:85b3fd62ea1a 62 * @note Synchronization level: Thread safe
NYX 0:85b3fd62ea1a 63 *
NYX 0:85b3fd62ea1a 64 * @note: This class must only be used in a static context -
NYX 0:85b3fd62ea1a 65 * this class must never be allocated or created on the
NYX 0:85b3fd62ea1a 66 * stack.
NYX 0:85b3fd62ea1a 67 *
NYX 0:85b3fd62ea1a 68 * @note: This class is lazily initialized on first use.
NYX 0:85b3fd62ea1a 69 * This class is a POD type so if it is not used it will
NYX 0:85b3fd62ea1a 70 * be garbage collected.
NYX 0:85b3fd62ea1a 71 * @ingroup platform
NYX 0:85b3fd62ea1a 72 */
NYX 0:85b3fd62ea1a 73 template <class T>
NYX 0:85b3fd62ea1a 74 struct SingletonPtr {
NYX 0:85b3fd62ea1a 75
NYX 0:85b3fd62ea1a 76 /** Get a pointer to the underlying singleton
NYX 0:85b3fd62ea1a 77 *
NYX 0:85b3fd62ea1a 78 * @returns
NYX 0:85b3fd62ea1a 79 * A pointer to the singleton
NYX 0:85b3fd62ea1a 80 */
NYX 0:85b3fd62ea1a 81 T* get() {
NYX 0:85b3fd62ea1a 82 if (NULL == _ptr) {
NYX 0:85b3fd62ea1a 83 singleton_lock();
NYX 0:85b3fd62ea1a 84 if (NULL == _ptr) {
NYX 0:85b3fd62ea1a 85 _ptr = new (_data) T();
NYX 0:85b3fd62ea1a 86 }
NYX 0:85b3fd62ea1a 87 singleton_unlock();
NYX 0:85b3fd62ea1a 88 }
NYX 0:85b3fd62ea1a 89 // _ptr was not zero initialized or was
NYX 0:85b3fd62ea1a 90 // corrupted if this assert is hit
NYX 0:85b3fd62ea1a 91 MBED_ASSERT(_ptr == (T *)&_data);
NYX 0:85b3fd62ea1a 92 return _ptr;
NYX 0:85b3fd62ea1a 93 }
NYX 0:85b3fd62ea1a 94
NYX 0:85b3fd62ea1a 95 /** Get a pointer to the underlying singleton
NYX 0:85b3fd62ea1a 96 *
NYX 0:85b3fd62ea1a 97 * @returns
NYX 0:85b3fd62ea1a 98 * A pointer to the singleton
NYX 0:85b3fd62ea1a 99 */
NYX 0:85b3fd62ea1a 100 T* operator->() {
NYX 0:85b3fd62ea1a 101 return get();
NYX 0:85b3fd62ea1a 102 }
NYX 0:85b3fd62ea1a 103
NYX 0:85b3fd62ea1a 104 // This is zero initialized when in global scope
NYX 0:85b3fd62ea1a 105 T *_ptr;
NYX 0:85b3fd62ea1a 106 // Force data to be 4 byte aligned
NYX 0:85b3fd62ea1a 107 uint32_t _data[(sizeof(T) + sizeof(uint32_t) - 1) / sizeof(uint32_t)];
NYX 0:85b3fd62ea1a 108 };
NYX 0:85b3fd62ea1a 109
NYX 0:85b3fd62ea1a 110 #endif
NYX 0:85b3fd62ea1a 111