Nicolas Borla / Mbed OS BBR_1Ebene

BBR 1 Ebene

mbed-os/platform/SingletonPtr.h@0:fbdae7e6d805, 2018-05-14 (annotated)

Committer:
borlanic
Date:
Mon May 14 11:29:06 2018 +0000
Revision:
0:fbdae7e6d805
BBR

Who changed what in which revision?

UserRevisionLine numberNew contents of line
borlanic 0:fbdae7e6d805 1
borlanic 0:fbdae7e6d805 2 /** \addtogroup platform */
borlanic 0:fbdae7e6d805 3 /** @{*/
borlanic 0:fbdae7e6d805 4 /**
borlanic 0:fbdae7e6d805 5 * \defgroup platform_SingletonPtr SingletonPtr class
borlanic 0:fbdae7e6d805 6 * @{
borlanic 0:fbdae7e6d805 7 */
borlanic 0:fbdae7e6d805 8 /* mbed Microcontroller Library
borlanic 0:fbdae7e6d805 9 * Copyright (c) 2006-2013 ARM Limited
borlanic 0:fbdae7e6d805 10 *
borlanic 0:fbdae7e6d805 11 * Licensed under the Apache License, Version 2.0 (the "License");
borlanic 0:fbdae7e6d805 12 * you may not use this file except in compliance with the License.
borlanic 0:fbdae7e6d805 13 * You may obtain a copy of the License at
borlanic 0:fbdae7e6d805 14 *
borlanic 0:fbdae7e6d805 15 * http://www.apache.org/licenses/LICENSE-2.0
borlanic 0:fbdae7e6d805 16 *
borlanic 0:fbdae7e6d805 17 * Unless required by applicable law or agreed to in writing, software
borlanic 0:fbdae7e6d805 18 * distributed under the License is distributed on an "AS IS" BASIS,
borlanic 0:fbdae7e6d805 19 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
borlanic 0:fbdae7e6d805 20 * See the License for the specific language governing permissions and
borlanic 0:fbdae7e6d805 21 * limitations under the License.
borlanic 0:fbdae7e6d805 22 */
borlanic 0:fbdae7e6d805 23 #ifndef SINGLETONPTR_H
borlanic 0:fbdae7e6d805 24 #define SINGLETONPTR_H
borlanic 0:fbdae7e6d805 25
borlanic 0:fbdae7e6d805 26 #include <stdint.h>
borlanic 0:fbdae7e6d805 27 #include <new>
borlanic 0:fbdae7e6d805 28 #include "platform/mbed_assert.h"
borlanic 0:fbdae7e6d805 29 #ifdef MBED_CONF_RTOS_PRESENT
borlanic 0:fbdae7e6d805 30 #include "cmsis_os2.h"
borlanic 0:fbdae7e6d805 31 #endif
borlanic 0:fbdae7e6d805 32
borlanic 0:fbdae7e6d805 33 #ifdef MBED_CONF_RTOS_PRESENT
borlanic 0:fbdae7e6d805 34 extern osMutexId_t singleton_mutex_id;
borlanic 0:fbdae7e6d805 35 #endif
borlanic 0:fbdae7e6d805 36
borlanic 0:fbdae7e6d805 37 /** Lock the singleton mutex
borlanic 0:fbdae7e6d805 38 *
borlanic 0:fbdae7e6d805 39 * This function is typically used to provide
borlanic 0:fbdae7e6d805 40 * exclusive access when initializing a
borlanic 0:fbdae7e6d805 41 * global object.
borlanic 0:fbdae7e6d805 42 */
borlanic 0:fbdae7e6d805 43 inline static void singleton_lock(void)
borlanic 0:fbdae7e6d805 44 {
borlanic 0:fbdae7e6d805 45 #ifdef MBED_CONF_RTOS_PRESENT
borlanic 0:fbdae7e6d805 46 osMutexAcquire(singleton_mutex_id, osWaitForever);
borlanic 0:fbdae7e6d805 47 #endif
borlanic 0:fbdae7e6d805 48 }
borlanic 0:fbdae7e6d805 49
borlanic 0:fbdae7e6d805 50 /** Unlock the singleton mutex
borlanic 0:fbdae7e6d805 51 *
borlanic 0:fbdae7e6d805 52 * This function is typically used to provide
borlanic 0:fbdae7e6d805 53 * exclusive access when initializing a
borlanic 0:fbdae7e6d805 54 * global object.
borlanic 0:fbdae7e6d805 55 */
borlanic 0:fbdae7e6d805 56 inline static void singleton_unlock(void)
borlanic 0:fbdae7e6d805 57 {
borlanic 0:fbdae7e6d805 58 #ifdef MBED_CONF_RTOS_PRESENT
borlanic 0:fbdae7e6d805 59 osMutexRelease (singleton_mutex_id);
borlanic 0:fbdae7e6d805 60 #endif
borlanic 0:fbdae7e6d805 61 }
borlanic 0:fbdae7e6d805 62
borlanic 0:fbdae7e6d805 63 /** Utility class for creating an using a singleton
borlanic 0:fbdae7e6d805 64 *
borlanic 0:fbdae7e6d805 65 * @note Synchronization level: Thread safe
borlanic 0:fbdae7e6d805 66 *
borlanic 0:fbdae7e6d805 67 * @note: This class must only be used in a static context -
borlanic 0:fbdae7e6d805 68 * this class must never be allocated or created on the
borlanic 0:fbdae7e6d805 69 * stack.
borlanic 0:fbdae7e6d805 70 *
borlanic 0:fbdae7e6d805 71 * @note: This class is lazily initialized on first use.
borlanic 0:fbdae7e6d805 72 * This class is a POD type so if it is not used it will
borlanic 0:fbdae7e6d805 73 * be garbage collected.
borlanic 0:fbdae7e6d805 74 */
borlanic 0:fbdae7e6d805 75 template <class T>
borlanic 0:fbdae7e6d805 76 struct SingletonPtr {
borlanic 0:fbdae7e6d805 77
borlanic 0:fbdae7e6d805 78 /** Get a pointer to the underlying singleton
borlanic 0:fbdae7e6d805 79 *
borlanic 0:fbdae7e6d805 80 * @returns
borlanic 0:fbdae7e6d805 81 * A pointer to the singleton
borlanic 0:fbdae7e6d805 82 */
borlanic 0:fbdae7e6d805 83 T* get() {
borlanic 0:fbdae7e6d805 84 if (NULL == _ptr) {
borlanic 0:fbdae7e6d805 85 singleton_lock();
borlanic 0:fbdae7e6d805 86 if (NULL == _ptr) {
borlanic 0:fbdae7e6d805 87 _ptr = new (_data) T();
borlanic 0:fbdae7e6d805 88 }
borlanic 0:fbdae7e6d805 89 singleton_unlock();
borlanic 0:fbdae7e6d805 90 }
borlanic 0:fbdae7e6d805 91 // _ptr was not zero initialized or was
borlanic 0:fbdae7e6d805 92 // corrupted if this assert is hit
borlanic 0:fbdae7e6d805 93 MBED_ASSERT(_ptr == (T *)&_data);
borlanic 0:fbdae7e6d805 94 return _ptr;
borlanic 0:fbdae7e6d805 95 }
borlanic 0:fbdae7e6d805 96
borlanic 0:fbdae7e6d805 97 /** Get a pointer to the underlying singleton
borlanic 0:fbdae7e6d805 98 *
borlanic 0:fbdae7e6d805 99 * @returns
borlanic 0:fbdae7e6d805 100 * A pointer to the singleton
borlanic 0:fbdae7e6d805 101 */
borlanic 0:fbdae7e6d805 102 T* operator->() {
borlanic 0:fbdae7e6d805 103 return get();
borlanic 0:fbdae7e6d805 104 }
borlanic 0:fbdae7e6d805 105
borlanic 0:fbdae7e6d805 106 // This is zero initialized when in global scope
borlanic 0:fbdae7e6d805 107 T *_ptr;
borlanic 0:fbdae7e6d805 108 // Force data to be 4 byte aligned
borlanic 0:fbdae7e6d805 109 uint32_t _data[(sizeof(T) + sizeof(uint32_t) - 1) / sizeof(uint32_t)];
borlanic 0:fbdae7e6d805 110 };
borlanic 0:fbdae7e6d805 111
borlanic 0:fbdae7e6d805 112 #endif
borlanic 0:fbdae7e6d805 113 /**@}*/
borlanic 0:fbdae7e6d805 114
borlanic 0:fbdae7e6d805 115 /**@}*/