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hal/api/SingletonPtr.h@1:d96dbedaebdb, 2016-11-04 (annotated)

Committer:
nexpaq
Date:
Fri Nov 04 20:54:50 2016 +0000
Revision:
1:d96dbedaebdb
Parent:
0:6c56fb4bc5f0 
Removed extra directories for other platforms

Who changed what in which revision?

UserRevisionLine numberNew contents of line
nexpaq 0:6c56fb4bc5f0 1 /* mbed Microcontroller Library
nexpaq 0:6c56fb4bc5f0 2 * Copyright (c) 2006-2013 ARM Limited
nexpaq 0:6c56fb4bc5f0 3 *
nexpaq 0:6c56fb4bc5f0 4 * Licensed under the Apache License, Version 2.0 (the "License");
nexpaq 0:6c56fb4bc5f0 5 * you may not use this file except in compliance with the License.
nexpaq 0:6c56fb4bc5f0 6 * You may obtain a copy of the License at
nexpaq 0:6c56fb4bc5f0 7 *
nexpaq 0:6c56fb4bc5f0 8 * http://www.apache.org/licenses/LICENSE-2.0
nexpaq 0:6c56fb4bc5f0 9 *
nexpaq 0:6c56fb4bc5f0 10 * Unless required by applicable law or agreed to in writing, software
nexpaq 0:6c56fb4bc5f0 11 * distributed under the License is distributed on an "AS IS" BASIS,
nexpaq 0:6c56fb4bc5f0 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
nexpaq 0:6c56fb4bc5f0 13 * See the License for the specific language governing permissions and
nexpaq 0:6c56fb4bc5f0 14 * limitations under the License.
nexpaq 0:6c56fb4bc5f0 15 */
nexpaq 0:6c56fb4bc5f0 16 #ifndef SINGLETONPTR_H
nexpaq 0:6c56fb4bc5f0 17 #define SINGLETONPTR_H
nexpaq 0:6c56fb4bc5f0 18
nexpaq 0:6c56fb4bc5f0 19 #include <stdint.h>
nexpaq 0:6c56fb4bc5f0 20 #include <new>
nexpaq 0:6c56fb4bc5f0 21 #include "mbed_assert.h"
nexpaq 0:6c56fb4bc5f0 22 #ifdef MBED_CONF_RTOS_PRESENT
nexpaq 0:6c56fb4bc5f0 23 #include "cmsis_os.h"
nexpaq 0:6c56fb4bc5f0 24 #endif
nexpaq 0:6c56fb4bc5f0 25
nexpaq 0:6c56fb4bc5f0 26 #ifdef MBED_CONF_RTOS_PRESENT
nexpaq 0:6c56fb4bc5f0 27 extern osMutexId singleton_mutex_id;
nexpaq 0:6c56fb4bc5f0 28 #endif
nexpaq 0:6c56fb4bc5f0 29
nexpaq 0:6c56fb4bc5f0 30 /** Lock the singleton mutex
nexpaq 0:6c56fb4bc5f0 31 *
nexpaq 0:6c56fb4bc5f0 32 * This function is typically used to provide
nexpaq 0:6c56fb4bc5f0 33 * exclusive access when initializing a
nexpaq 0:6c56fb4bc5f0 34 * global object.
nexpaq 0:6c56fb4bc5f0 35 */
nexpaq 0:6c56fb4bc5f0 36 inline static void singleton_lock(void)
nexpaq 0:6c56fb4bc5f0 37 {
nexpaq 0:6c56fb4bc5f0 38 #ifdef MBED_CONF_RTOS_PRESENT
nexpaq 0:6c56fb4bc5f0 39 osMutexWait(singleton_mutex_id, osWaitForever);
nexpaq 0:6c56fb4bc5f0 40 #endif
nexpaq 0:6c56fb4bc5f0 41 }
nexpaq 0:6c56fb4bc5f0 42
nexpaq 0:6c56fb4bc5f0 43 /** Unlock the singleton mutex
nexpaq 0:6c56fb4bc5f0 44 *
nexpaq 0:6c56fb4bc5f0 45 * This function is typically used to provide
nexpaq 0:6c56fb4bc5f0 46 * exclusive access when initializing a
nexpaq 0:6c56fb4bc5f0 47 * global object.
nexpaq 0:6c56fb4bc5f0 48 */
nexpaq 0:6c56fb4bc5f0 49 inline static void singleton_unlock(void)
nexpaq 0:6c56fb4bc5f0 50 {
nexpaq 0:6c56fb4bc5f0 51 #ifdef MBED_CONF_RTOS_PRESENT
nexpaq 0:6c56fb4bc5f0 52 osMutexRelease (singleton_mutex_id);
nexpaq 0:6c56fb4bc5f0 53 #endif
nexpaq 0:6c56fb4bc5f0 54 }
nexpaq 0:6c56fb4bc5f0 55
nexpaq 0:6c56fb4bc5f0 56 /** Utility class for creating an using a singleton
nexpaq 0:6c56fb4bc5f0 57 *
nexpaq 0:6c56fb4bc5f0 58 * @Note Synchronization level: Thread safe
nexpaq 0:6c56fb4bc5f0 59 *
nexpaq 0:6c56fb4bc5f0 60 * @Note: This class must only be used in a static context -
nexpaq 0:6c56fb4bc5f0 61 * this class must never be allocated or created on the
nexpaq 0:6c56fb4bc5f0 62 * stack.
nexpaq 0:6c56fb4bc5f0 63 *
nexpaq 0:6c56fb4bc5f0 64 * @Note: This class is lazily initialized on first use.
nexpaq 0:6c56fb4bc5f0 65 * This class is a POD type so if it is not used it will
nexpaq 0:6c56fb4bc5f0 66 * be garbage collected.
nexpaq 0:6c56fb4bc5f0 67 */
nexpaq 0:6c56fb4bc5f0 68 template <class T>
nexpaq 0:6c56fb4bc5f0 69 struct SingletonPtr {
nexpaq 0:6c56fb4bc5f0 70
nexpaq 0:6c56fb4bc5f0 71 /** Get a pointer to the underlying singleton
nexpaq 0:6c56fb4bc5f0 72 *
nexpaq 0:6c56fb4bc5f0 73 * @returns
nexpaq 0:6c56fb4bc5f0 74 * A pointer to the singleton
nexpaq 0:6c56fb4bc5f0 75 */
nexpaq 0:6c56fb4bc5f0 76 T* get() {
nexpaq 0:6c56fb4bc5f0 77 if (NULL == _ptr) {
nexpaq 0:6c56fb4bc5f0 78 singleton_lock();
nexpaq 0:6c56fb4bc5f0 79 if (NULL == _ptr) {
nexpaq 0:6c56fb4bc5f0 80 _ptr = new (_data) T();
nexpaq 0:6c56fb4bc5f0 81 }
nexpaq 0:6c56fb4bc5f0 82 singleton_unlock();
nexpaq 0:6c56fb4bc5f0 83 }
nexpaq 0:6c56fb4bc5f0 84 // _ptr was not zero initialized or was
nexpaq 0:6c56fb4bc5f0 85 // corrupted if this assert is hit
nexpaq 0:6c56fb4bc5f0 86 MBED_ASSERT(_ptr == (T *)&_data);
nexpaq 0:6c56fb4bc5f0 87 return _ptr;
nexpaq 0:6c56fb4bc5f0 88 }
nexpaq 0:6c56fb4bc5f0 89
nexpaq 0:6c56fb4bc5f0 90 /** Get a pointer to the underlying singleton
nexpaq 0:6c56fb4bc5f0 91 *
nexpaq 0:6c56fb4bc5f0 92 * @returns
nexpaq 0:6c56fb4bc5f0 93 * A pointer to the singleton
nexpaq 0:6c56fb4bc5f0 94 */
nexpaq 0:6c56fb4bc5f0 95 T* operator->() {
nexpaq 0:6c56fb4bc5f0 96 return get();
nexpaq 0:6c56fb4bc5f0 97 }
nexpaq 0:6c56fb4bc5f0 98
nexpaq 0:6c56fb4bc5f0 99 // This is zero initialized when in global scope
nexpaq 0:6c56fb4bc5f0 100 T *_ptr;
nexpaq 0:6c56fb4bc5f0 101 // Force data to be 4 byte aligned
nexpaq 0:6c56fb4bc5f0 102 uint32_t _data[(sizeof(T) + sizeof(uint32_t) - 1) / sizeof(uint32_t)];
nexpaq 0:6c56fb4bc5f0 103 };
nexpaq 0:6c56fb4bc5f0 104
nexpaq 0:6c56fb4bc5f0 105 #endif