Mateusz Kowalik / Application_danix

,,

Fork of Application by Daniel Sygut

mbed-dev/platform/SingletonPtr.h@15:2a20c3d2616e, 2018-02-15 (annotated)

Committer:
Zaitsev
Date:
Thu Feb 15 14:29:23 2018 +0000
Revision:
15:2a20c3d2616e
Parent:
10:41552d038a69 
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Who changed what in which revision?

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Zaitsev 10:41552d038a69 1
Zaitsev 10:41552d038a69 2 /** \addtogroup platform */
Zaitsev 10:41552d038a69 3 /** @{*/
Zaitsev 10:41552d038a69 4 /* mbed Microcontroller Library
Zaitsev 10:41552d038a69 5 * Copyright (c) 2006-2013 ARM Limited
Zaitsev 10:41552d038a69 6 *
Zaitsev 10:41552d038a69 7 * Licensed under the Apache License, Version 2.0 (the "License");
Zaitsev 10:41552d038a69 8 * you may not use this file except in compliance with the License.
Zaitsev 10:41552d038a69 9 * You may obtain a copy of the License at
Zaitsev 10:41552d038a69 10 *
Zaitsev 10:41552d038a69 11 * http://www.apache.org/licenses/LICENSE-2.0
Zaitsev 10:41552d038a69 12 *
Zaitsev 10:41552d038a69 13 * Unless required by applicable law or agreed to in writing, software
Zaitsev 10:41552d038a69 14 * distributed under the License is distributed on an "AS IS" BASIS,
Zaitsev 10:41552d038a69 15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
Zaitsev 10:41552d038a69 16 * See the License for the specific language governing permissions and
Zaitsev 10:41552d038a69 17 * limitations under the License.
Zaitsev 10:41552d038a69 18 */
Zaitsev 10:41552d038a69 19 #ifndef SINGLETONPTR_H
Zaitsev 10:41552d038a69 20 #define SINGLETONPTR_H
Zaitsev 10:41552d038a69 21
Zaitsev 10:41552d038a69 22 #include <stdint.h>
Zaitsev 10:41552d038a69 23 #include <new>
Zaitsev 10:41552d038a69 24 #include "platform/mbed_assert.h"
Zaitsev 10:41552d038a69 25 #ifdef MBED_CONF_RTOS_PRESENT
Zaitsev 10:41552d038a69 26 #include "cmsis_os.h"
Zaitsev 10:41552d038a69 27 #endif
Zaitsev 10:41552d038a69 28
Zaitsev 10:41552d038a69 29 #ifdef MBED_CONF_RTOS_PRESENT
Zaitsev 10:41552d038a69 30 extern osMutexId singleton_mutex_id;
Zaitsev 10:41552d038a69 31 #endif
Zaitsev 10:41552d038a69 32
Zaitsev 10:41552d038a69 33 /** Lock the singleton mutex
Zaitsev 10:41552d038a69 34 *
Zaitsev 10:41552d038a69 35 * This function is typically used to provide
Zaitsev 10:41552d038a69 36 * exclusive access when initializing a
Zaitsev 10:41552d038a69 37 * global object.
Zaitsev 10:41552d038a69 38 */
Zaitsev 10:41552d038a69 39 inline static void singleton_lock(void)
Zaitsev 10:41552d038a69 40 {
Zaitsev 10:41552d038a69 41 #ifdef MBED_CONF_RTOS_PRESENT
Zaitsev 10:41552d038a69 42 osMutexWait(singleton_mutex_id, osWaitForever);
Zaitsev 10:41552d038a69 43 #endif
Zaitsev 10:41552d038a69 44 }
Zaitsev 10:41552d038a69 45
Zaitsev 10:41552d038a69 46 /** Unlock the singleton mutex
Zaitsev 10:41552d038a69 47 *
Zaitsev 10:41552d038a69 48 * This function is typically used to provide
Zaitsev 10:41552d038a69 49 * exclusive access when initializing a
Zaitsev 10:41552d038a69 50 * global object.
Zaitsev 10:41552d038a69 51 */
Zaitsev 10:41552d038a69 52 inline static void singleton_unlock(void)
Zaitsev 10:41552d038a69 53 {
Zaitsev 10:41552d038a69 54 #ifdef MBED_CONF_RTOS_PRESENT
Zaitsev 10:41552d038a69 55 osMutexRelease (singleton_mutex_id);
Zaitsev 10:41552d038a69 56 #endif
Zaitsev 10:41552d038a69 57 }
Zaitsev 10:41552d038a69 58
Zaitsev 10:41552d038a69 59 /** Utility class for creating an using a singleton
Zaitsev 10:41552d038a69 60 *
Zaitsev 10:41552d038a69 61 * @Note Synchronization level: Thread safe
Zaitsev 10:41552d038a69 62 *
Zaitsev 10:41552d038a69 63 * @Note: This class must only be used in a static context -
Zaitsev 10:41552d038a69 64 * this class must never be allocated or created on the
Zaitsev 10:41552d038a69 65 * stack.
Zaitsev 10:41552d038a69 66 *
Zaitsev 10:41552d038a69 67 * @Note: This class is lazily initialized on first use.
Zaitsev 10:41552d038a69 68 * This class is a POD type so if it is not used it will
Zaitsev 10:41552d038a69 69 * be garbage collected.
Zaitsev 10:41552d038a69 70 */
Zaitsev 10:41552d038a69 71 template <class T>
Zaitsev 10:41552d038a69 72 struct SingletonPtr {
Zaitsev 10:41552d038a69 73
Zaitsev 10:41552d038a69 74 /** Get a pointer to the underlying singleton
Zaitsev 10:41552d038a69 75 *
Zaitsev 10:41552d038a69 76 * @returns
Zaitsev 10:41552d038a69 77 * A pointer to the singleton
Zaitsev 10:41552d038a69 78 */
Zaitsev 10:41552d038a69 79 T* get() {
Zaitsev 10:41552d038a69 80 if (NULL == _ptr) {
Zaitsev 10:41552d038a69 81 singleton_lock();
Zaitsev 10:41552d038a69 82 if (NULL == _ptr) {
Zaitsev 10:41552d038a69 83 _ptr = new (_data) T();
Zaitsev 10:41552d038a69 84 }
Zaitsev 10:41552d038a69 85 singleton_unlock();
Zaitsev 10:41552d038a69 86 }
Zaitsev 10:41552d038a69 87 // _ptr was not zero initialized or was
Zaitsev 10:41552d038a69 88 // corrupted if this assert is hit
Zaitsev 10:41552d038a69 89 MBED_ASSERT(_ptr == (T *)&_data);
Zaitsev 10:41552d038a69 90 return _ptr;
Zaitsev 10:41552d038a69 91 }
Zaitsev 10:41552d038a69 92
Zaitsev 10:41552d038a69 93 /** Get a pointer to the underlying singleton
Zaitsev 10:41552d038a69 94 *
Zaitsev 10:41552d038a69 95 * @returns
Zaitsev 10:41552d038a69 96 * A pointer to the singleton
Zaitsev 10:41552d038a69 97 */
Zaitsev 10:41552d038a69 98 T* operator->() {
Zaitsev 10:41552d038a69 99 return get();
Zaitsev 10:41552d038a69 100 }
Zaitsev 10:41552d038a69 101
Zaitsev 10:41552d038a69 102 // This is zero initialized when in global scope
Zaitsev 10:41552d038a69 103 T *_ptr;
Zaitsev 10:41552d038a69 104 // Force data to be 4 byte aligned
Zaitsev 10:41552d038a69 105 uint32_t _data[(sizeof(T) + sizeof(uint32_t) - 1) / sizeof(uint32_t)];
Zaitsev 10:41552d038a69 106 };
Zaitsev 10:41552d038a69 107
Zaitsev 10:41552d038a69 108 #endif
Zaitsev 10:41552d038a69 109
Zaitsev 10:41552d038a69 110 /** @}*/