EL4121 Embedded System / mbed-os

mbed-os

Dependents:   cobaLCDJoyMotor_Thread odometry_omni_3roda_v3 odometry_omni_3roda_v1 odometry_omni_3roda_v2 ... more

platform/SingletonPtr.h@0:b74591d5ab33, 2017-12-11 (annotated)

Committer:
be_bryan
Date:
Mon Dec 11 17:54:04 2017 +0000
Revision:
0:b74591d5ab33
motor ++

Who changed what in which revision?

UserRevisionLine numberNew contents of line
be_bryan 0:b74591d5ab33 1
be_bryan 0:b74591d5ab33 2 /** \addtogroup platform */
be_bryan 0:b74591d5ab33 3 /** @{*/
be_bryan 0:b74591d5ab33 4 /**
be_bryan 0:b74591d5ab33 5 * \defgroup platform_SingletonPtr SingletonPtr class
be_bryan 0:b74591d5ab33 6 * @{
be_bryan 0:b74591d5ab33 7 */
be_bryan 0:b74591d5ab33 8 /* mbed Microcontroller Library
be_bryan 0:b74591d5ab33 9 * Copyright (c) 2006-2013 ARM Limited
be_bryan 0:b74591d5ab33 10 *
be_bryan 0:b74591d5ab33 11 * Licensed under the Apache License, Version 2.0 (the "License");
be_bryan 0:b74591d5ab33 12 * you may not use this file except in compliance with the License.
be_bryan 0:b74591d5ab33 13 * You may obtain a copy of the License at
be_bryan 0:b74591d5ab33 14 *
be_bryan 0:b74591d5ab33 15 * http://www.apache.org/licenses/LICENSE-2.0
be_bryan 0:b74591d5ab33 16 *
be_bryan 0:b74591d5ab33 17 * Unless required by applicable law or agreed to in writing, software
be_bryan 0:b74591d5ab33 18 * distributed under the License is distributed on an "AS IS" BASIS,
be_bryan 0:b74591d5ab33 19 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
be_bryan 0:b74591d5ab33 20 * See the License for the specific language governing permissions and
be_bryan 0:b74591d5ab33 21 * limitations under the License.
be_bryan 0:b74591d5ab33 22 */
be_bryan 0:b74591d5ab33 23 #ifndef SINGLETONPTR_H
be_bryan 0:b74591d5ab33 24 #define SINGLETONPTR_H
be_bryan 0:b74591d5ab33 25
be_bryan 0:b74591d5ab33 26 #include <stdint.h>
be_bryan 0:b74591d5ab33 27 #include <new>
be_bryan 0:b74591d5ab33 28 #include "platform/mbed_assert.h"
be_bryan 0:b74591d5ab33 29 #ifdef MBED_CONF_RTOS_PRESENT
be_bryan 0:b74591d5ab33 30 #include "cmsis_os2.h"
be_bryan 0:b74591d5ab33 31 #endif
be_bryan 0:b74591d5ab33 32
be_bryan 0:b74591d5ab33 33 #ifdef MBED_CONF_RTOS_PRESENT
be_bryan 0:b74591d5ab33 34 extern osMutexId_t singleton_mutex_id;
be_bryan 0:b74591d5ab33 35 #endif
be_bryan 0:b74591d5ab33 36
be_bryan 0:b74591d5ab33 37 /** Lock the singleton mutex
be_bryan 0:b74591d5ab33 38 *
be_bryan 0:b74591d5ab33 39 * This function is typically used to provide
be_bryan 0:b74591d5ab33 40 * exclusive access when initializing a
be_bryan 0:b74591d5ab33 41 * global object.
be_bryan 0:b74591d5ab33 42 */
be_bryan 0:b74591d5ab33 43 inline static void singleton_lock(void)
be_bryan 0:b74591d5ab33 44 {
be_bryan 0:b74591d5ab33 45 #ifdef MBED_CONF_RTOS_PRESENT
be_bryan 0:b74591d5ab33 46 osMutexAcquire(singleton_mutex_id, osWaitForever);
be_bryan 0:b74591d5ab33 47 #endif
be_bryan 0:b74591d5ab33 48 }
be_bryan 0:b74591d5ab33 49
be_bryan 0:b74591d5ab33 50 /** Unlock the singleton mutex
be_bryan 0:b74591d5ab33 51 *
be_bryan 0:b74591d5ab33 52 * This function is typically used to provide
be_bryan 0:b74591d5ab33 53 * exclusive access when initializing a
be_bryan 0:b74591d5ab33 54 * global object.
be_bryan 0:b74591d5ab33 55 */
be_bryan 0:b74591d5ab33 56 inline static void singleton_unlock(void)
be_bryan 0:b74591d5ab33 57 {
be_bryan 0:b74591d5ab33 58 #ifdef MBED_CONF_RTOS_PRESENT
be_bryan 0:b74591d5ab33 59 osMutexRelease (singleton_mutex_id);
be_bryan 0:b74591d5ab33 60 #endif
be_bryan 0:b74591d5ab33 61 }
be_bryan 0:b74591d5ab33 62
be_bryan 0:b74591d5ab33 63 /** Utility class for creating an using a singleton
be_bryan 0:b74591d5ab33 64 *
be_bryan 0:b74591d5ab33 65 * @note Synchronization level: Thread safe
be_bryan 0:b74591d5ab33 66 *
be_bryan 0:b74591d5ab33 67 * @note: This class must only be used in a static context -
be_bryan 0:b74591d5ab33 68 * this class must never be allocated or created on the
be_bryan 0:b74591d5ab33 69 * stack.
be_bryan 0:b74591d5ab33 70 *
be_bryan 0:b74591d5ab33 71 * @note: This class is lazily initialized on first use.
be_bryan 0:b74591d5ab33 72 * This class is a POD type so if it is not used it will
be_bryan 0:b74591d5ab33 73 * be garbage collected.
be_bryan 0:b74591d5ab33 74 */
be_bryan 0:b74591d5ab33 75 template <class T>
be_bryan 0:b74591d5ab33 76 struct SingletonPtr {
be_bryan 0:b74591d5ab33 77
be_bryan 0:b74591d5ab33 78 /** Get a pointer to the underlying singleton
be_bryan 0:b74591d5ab33 79 *
be_bryan 0:b74591d5ab33 80 * @returns
be_bryan 0:b74591d5ab33 81 * A pointer to the singleton
be_bryan 0:b74591d5ab33 82 */
be_bryan 0:b74591d5ab33 83 T* get() {
be_bryan 0:b74591d5ab33 84 if (NULL == _ptr) {
be_bryan 0:b74591d5ab33 85 singleton_lock();
be_bryan 0:b74591d5ab33 86 if (NULL == _ptr) {
be_bryan 0:b74591d5ab33 87 _ptr = new (_data) T();
be_bryan 0:b74591d5ab33 88 }
be_bryan 0:b74591d5ab33 89 singleton_unlock();
be_bryan 0:b74591d5ab33 90 }
be_bryan 0:b74591d5ab33 91 // _ptr was not zero initialized or was
be_bryan 0:b74591d5ab33 92 // corrupted if this assert is hit
be_bryan 0:b74591d5ab33 93 MBED_ASSERT(_ptr == (T *)&_data);
be_bryan 0:b74591d5ab33 94 return _ptr;
be_bryan 0:b74591d5ab33 95 }
be_bryan 0:b74591d5ab33 96
be_bryan 0:b74591d5ab33 97 /** Get a pointer to the underlying singleton
be_bryan 0:b74591d5ab33 98 *
be_bryan 0:b74591d5ab33 99 * @returns
be_bryan 0:b74591d5ab33 100 * A pointer to the singleton
be_bryan 0:b74591d5ab33 101 */
be_bryan 0:b74591d5ab33 102 T* operator->() {
be_bryan 0:b74591d5ab33 103 return get();
be_bryan 0:b74591d5ab33 104 }
be_bryan 0:b74591d5ab33 105
be_bryan 0:b74591d5ab33 106 // This is zero initialized when in global scope
be_bryan 0:b74591d5ab33 107 T *_ptr;
be_bryan 0:b74591d5ab33 108 // Force data to be 4 byte aligned
be_bryan 0:b74591d5ab33 109 uint32_t _data[(sizeof(T) + sizeof(uint32_t) - 1) / sizeof(uint32_t)];
be_bryan 0:b74591d5ab33 110 };
be_bryan 0:b74591d5ab33 111
be_bryan 0:b74591d5ab33 112 #endif
be_bryan 0:b74591d5ab33 113 /**@}*/
be_bryan 0:b74591d5ab33 114
be_bryan 0:b74591d5ab33 115 /**@}*/