1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in 12 * the documentation and/or other materials provided with the 13 * distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #ifndef _BIONIC_THREAD_LOCAL_BUFFER_H_included 30 #define _BIONIC_THREAD_LOCAL_BUFFER_H_included 31 32 #include <malloc.h> 33 #include <pthread.h> 34 35 // TODO: use __thread instead? 36 37 template <typename T, size_t Size = sizeof(T)> 38 class ThreadLocalBuffer { 39 public: ThreadLocalBuffer()40 ThreadLocalBuffer() { 41 // We used to use pthread_once to initialize the keys, but life is more predictable 42 // if we allocate them all up front when the C library starts up, via __constructor__. 43 pthread_key_create(&key_, free); 44 } 45 get()46 T* get() { 47 T* result = reinterpret_cast<T*>(pthread_getspecific(key_)); 48 if (result == nullptr) { 49 result = reinterpret_cast<T*>(calloc(1, Size)); 50 pthread_setspecific(key_, result); 51 } 52 return result; 53 } 54 size()55 size_t size() { return Size; } 56 57 private: 58 pthread_key_t key_; 59 }; 60 61 #endif // _BIONIC_THREAD_LOCAL_BUFFER_H_included 62