Daiki Kato / mbed-os-lychee

mbed-os for GR-LYCHEE

Dependents:   mbed-os-example-blinky-gr-lychee GR-Boads_Camera_sample GR-Boards_Audio_Recoder GR-Boads_Camera_DisplayApp ... more

platform/SingletonPtr.h@0:f782d9c66c49, 2018-02-02 (annotated)

Committer:
dkato
Date:
Fri Feb 02 05:42:23 2018 +0000
Revision:
0:f782d9c66c49
mbed-os for GR-LYCHEE

Who changed what in which revision?

UserRevisionLine numberNew contents of line
dkato 0:f782d9c66c49 1
dkato 0:f782d9c66c49 2 /** \addtogroup platform */
dkato 0:f782d9c66c49 3 /** @{*/
dkato 0:f782d9c66c49 4 /* mbed Microcontroller Library
dkato 0:f782d9c66c49 5 * Copyright (c) 2006-2013 ARM Limited
dkato 0:f782d9c66c49 6 *
dkato 0:f782d9c66c49 7 * Licensed under the Apache License, Version 2.0 (the "License");
dkato 0:f782d9c66c49 8 * you may not use this file except in compliance with the License.
dkato 0:f782d9c66c49 9 * You may obtain a copy of the License at
dkato 0:f782d9c66c49 10 *
dkato 0:f782d9c66c49 11 * http://www.apache.org/licenses/LICENSE-2.0
dkato 0:f782d9c66c49 12 *
dkato 0:f782d9c66c49 13 * Unless required by applicable law or agreed to in writing, software
dkato 0:f782d9c66c49 14 * distributed under the License is distributed on an "AS IS" BASIS,
dkato 0:f782d9c66c49 15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
dkato 0:f782d9c66c49 16 * See the License for the specific language governing permissions and
dkato 0:f782d9c66c49 17 * limitations under the License.
dkato 0:f782d9c66c49 18 */
dkato 0:f782d9c66c49 19 #ifndef SINGLETONPTR_H
dkato 0:f782d9c66c49 20 #define SINGLETONPTR_H
dkato 0:f782d9c66c49 21
dkato 0:f782d9c66c49 22 #include <stdint.h>
dkato 0:f782d9c66c49 23 #include <new>
dkato 0:f782d9c66c49 24 #include "platform/mbed_assert.h"
dkato 0:f782d9c66c49 25 #ifdef MBED_CONF_RTOS_PRESENT
dkato 0:f782d9c66c49 26 #include "cmsis_os.h"
dkato 0:f782d9c66c49 27 #endif
dkato 0:f782d9c66c49 28
dkato 0:f782d9c66c49 29 #ifdef MBED_CONF_RTOS_PRESENT
dkato 0:f782d9c66c49 30 extern osMutexId singleton_mutex_id;
dkato 0:f782d9c66c49 31 #endif
dkato 0:f782d9c66c49 32
dkato 0:f782d9c66c49 33 /** Lock the singleton mutex
dkato 0:f782d9c66c49 34 *
dkato 0:f782d9c66c49 35 * This function is typically used to provide
dkato 0:f782d9c66c49 36 * exclusive access when initializing a
dkato 0:f782d9c66c49 37 * global object.
dkato 0:f782d9c66c49 38 */
dkato 0:f782d9c66c49 39 inline static void singleton_lock(void)
dkato 0:f782d9c66c49 40 {
dkato 0:f782d9c66c49 41 #ifdef MBED_CONF_RTOS_PRESENT
dkato 0:f782d9c66c49 42 osMutexWait(singleton_mutex_id, osWaitForever);
dkato 0:f782d9c66c49 43 #endif
dkato 0:f782d9c66c49 44 }
dkato 0:f782d9c66c49 45
dkato 0:f782d9c66c49 46 /** Unlock the singleton mutex
dkato 0:f782d9c66c49 47 *
dkato 0:f782d9c66c49 48 * This function is typically used to provide
dkato 0:f782d9c66c49 49 * exclusive access when initializing a
dkato 0:f782d9c66c49 50 * global object.
dkato 0:f782d9c66c49 51 */
dkato 0:f782d9c66c49 52 inline static void singleton_unlock(void)
dkato 0:f782d9c66c49 53 {
dkato 0:f782d9c66c49 54 #ifdef MBED_CONF_RTOS_PRESENT
dkato 0:f782d9c66c49 55 osMutexRelease (singleton_mutex_id);
dkato 0:f782d9c66c49 56 #endif
dkato 0:f782d9c66c49 57 }
dkato 0:f782d9c66c49 58
dkato 0:f782d9c66c49 59 /** Utility class for creating an using a singleton
dkato 0:f782d9c66c49 60 *
dkato 0:f782d9c66c49 61 * @Note Synchronization level: Thread safe
dkato 0:f782d9c66c49 62 *
dkato 0:f782d9c66c49 63 * @Note: This class must only be used in a static context -
dkato 0:f782d9c66c49 64 * this class must never be allocated or created on the
dkato 0:f782d9c66c49 65 * stack.
dkato 0:f782d9c66c49 66 *
dkato 0:f782d9c66c49 67 * @Note: This class is lazily initialized on first use.
dkato 0:f782d9c66c49 68 * This class is a POD type so if it is not used it will
dkato 0:f782d9c66c49 69 * be garbage collected.
dkato 0:f782d9c66c49 70 */
dkato 0:f782d9c66c49 71 template <class T>
dkato 0:f782d9c66c49 72 struct SingletonPtr {
dkato 0:f782d9c66c49 73
dkato 0:f782d9c66c49 74 /** Get a pointer to the underlying singleton
dkato 0:f782d9c66c49 75 *
dkato 0:f782d9c66c49 76 * @returns
dkato 0:f782d9c66c49 77 * A pointer to the singleton
dkato 0:f782d9c66c49 78 */
dkato 0:f782d9c66c49 79 T* get() {
dkato 0:f782d9c66c49 80 if (NULL == _ptr) {
dkato 0:f782d9c66c49 81 singleton_lock();
dkato 0:f782d9c66c49 82 if (NULL == _ptr) {
dkato 0:f782d9c66c49 83 _ptr = new (_data) T();
dkato 0:f782d9c66c49 84 }
dkato 0:f782d9c66c49 85 singleton_unlock();
dkato 0:f782d9c66c49 86 }
dkato 0:f782d9c66c49 87 // _ptr was not zero initialized or was
dkato 0:f782d9c66c49 88 // corrupted if this assert is hit
dkato 0:f782d9c66c49 89 MBED_ASSERT(_ptr == (T *)&_data);
dkato 0:f782d9c66c49 90 return _ptr;
dkato 0:f782d9c66c49 91 }
dkato 0:f782d9c66c49 92
dkato 0:f782d9c66c49 93 /** Get a pointer to the underlying singleton
dkato 0:f782d9c66c49 94 *
dkato 0:f782d9c66c49 95 * @returns
dkato 0:f782d9c66c49 96 * A pointer to the singleton
dkato 0:f782d9c66c49 97 */
dkato 0:f782d9c66c49 98 T* operator->() {
dkato 0:f782d9c66c49 99 return get();
dkato 0:f782d9c66c49 100 }
dkato 0:f782d9c66c49 101
dkato 0:f782d9c66c49 102 // This is zero initialized when in global scope
dkato 0:f782d9c66c49 103 T *_ptr;
dkato 0:f782d9c66c49 104 // Force data to be 4 byte aligned
dkato 0:f782d9c66c49 105 uint32_t _data[(sizeof(T) + sizeof(uint32_t) - 1) / sizeof(uint32_t)];
dkato 0:f782d9c66c49 106 };
dkato 0:f782d9c66c49 107
dkato 0:f782d9c66c49 108 #endif
dkato 0:f782d9c66c49 109
dkato 0:f782d9c66c49 110 /** @}*/