1 #ifndef _DESINGLETON_H 2 #define _DESINGLETON_H 3 /*------------------------------------------------------------------------- 4 * drawElements Thread Library 5 * --------------------------- 6 * 7 * Copyright 2014 The Android Open Source Project 8 * 9 * Licensed under the Apache License, Version 2.0 (the "License"); 10 * you may not use this file except in compliance with the License. 11 * You may obtain a copy of the License at 12 * 13 * http://www.apache.org/licenses/LICENSE-2.0 14 * 15 * Unless required by applicable law or agreed to in writing, software 16 * distributed under the License is distributed on an "AS IS" BASIS, 17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 18 * See the License for the specific language governing permissions and 19 * limitations under the License. 20 * 21 *//*! 22 * \file 23 * \brief Thread-safe singleton. 24 *//*--------------------------------------------------------------------*/ 25 26 #include "deDefs.h" 27 28 typedef enum deSingletonState_e 29 { 30 DE_SINGLETON_STATE_NOT_INITIALIZED = 0, 31 DE_SINGLETON_STATE_INITIALIZING, 32 DE_SINGLETON_STATE_INITIALIZED, 33 34 DE_SINGLETON_STATE_LAST 35 } deSingletonState; 36 37 DE_BEGIN_EXTERN_C 38 39 typedef void (*deSingletonConstructorFunc) (void* arg); 40 41 /*--------------------------------------------------------------------*//*! 42 * \brief Initialize singleton. 43 * 44 * This function ensures that singletonState = DE_SINGLETON_STATE_INITIALIZED 45 * upon return. 46 * 47 * If current singleton state is DE_SINGLETON_NOT_INITIALIZED, constructor 48 * function is called with the supplied argument (arg). 49 * 50 * It is guaranteed that constructor is called only once, even when multiple 51 * concurrent calls are made to deInitSingleton(). 52 * 53 * Note that singletonState memory location must be initialized to 54 * DE_SINGLETON_STATE_NOT_INITIALIZED prior to any calls to deInitSingleton(). 55 * 56 * \param singletonState Pointer to singleton state. 57 * \param constructor Constructor function. 58 * \param arg Generic arg pointer for constructor. 59 *//*--------------------------------------------------------------------*/ 60 void deInitSingleton (volatile deSingletonState* singletonState, deSingletonConstructorFunc constructor, void* arg); 61 62 void deSingleton_selfTest (void); 63 64 DE_END_EXTERN_C 65 66 #endif /* _DESINGLETON_H */ 67