1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */ 2 /* dbus-threads.h D-Bus threads handling 3 * 4 * Copyright (C) 2002 Red Hat Inc. 5 * 6 * Licensed under the Academic Free License version 2.1 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 * 22 */ 23 #if !defined (DBUS_INSIDE_DBUS_H) && !defined (DBUS_COMPILATION) 24 #error "Only <dbus/dbus.h> can be included directly, this file may disappear or change contents." 25 #endif 26 27 #ifndef DBUS_THREADS_H 28 #define DBUS_THREADS_H 29 30 #include <dbus/dbus-macros.h> 31 #include <dbus/dbus-types.h> 32 33 DBUS_BEGIN_DECLS 34 35 /** 36 * @addtogroup DBusThreads 37 * @{ 38 */ 39 40 /** An opaque mutex type provided by the #DBusThreadFunctions implementation installed by dbus_threads_init(). */ 41 typedef struct DBusMutex DBusMutex; 42 /** An opaque condition variable type provided by the #DBusThreadFunctions implementation installed by dbus_threads_init(). */ 43 typedef struct DBusCondVar DBusCondVar; 44 45 /** Deprecated, provide DBusRecursiveMutexNewFunction instead. */ 46 typedef DBusMutex* (* DBusMutexNewFunction) (void); 47 /** Deprecated, provide DBusRecursiveMutexFreeFunction instead. */ 48 typedef void (* DBusMutexFreeFunction) (DBusMutex *mutex); 49 /** Deprecated, provide DBusRecursiveMutexLockFunction instead. Return value is lock success, but gets ignored in practice. */ 50 typedef dbus_bool_t (* DBusMutexLockFunction) (DBusMutex *mutex); 51 /** Deprecated, provide DBusRecursiveMutexUnlockFunction instead. Return value is unlock success, but gets ignored in practice. */ 52 typedef dbus_bool_t (* DBusMutexUnlockFunction) (DBusMutex *mutex); 53 54 /** Creates a new recursively-lockable mutex, or returns #NULL if not 55 * enough memory. Can only fail due to lack of memory. Found in 56 * #DBusThreadFunctions. Do not just use PTHREAD_MUTEX_RECURSIVE for 57 * this, because it does not save/restore the recursion count when 58 * waiting on a condition. libdbus requires the Java-style behavior 59 * where the mutex is fully unlocked to wait on a condition. 60 */ 61 typedef DBusMutex* (* DBusRecursiveMutexNewFunction) (void); 62 /** Frees a recursively-lockable mutex. Found in #DBusThreadFunctions. 63 */ 64 typedef void (* DBusRecursiveMutexFreeFunction) (DBusMutex *mutex); 65 /** Locks a recursively-lockable mutex. Found in #DBusThreadFunctions. 66 * Can only fail due to lack of memory. 67 */ 68 typedef void (* DBusRecursiveMutexLockFunction) (DBusMutex *mutex); 69 /** Unlocks a recursively-lockable mutex. Found in #DBusThreadFunctions. 70 * Can only fail due to lack of memory. 71 */ 72 typedef void (* DBusRecursiveMutexUnlockFunction) (DBusMutex *mutex); 73 74 /** Creates a new condition variable. Found in #DBusThreadFunctions. 75 * Can only fail (returning #NULL) due to lack of memory. 76 */ 77 typedef DBusCondVar* (* DBusCondVarNewFunction) (void); 78 /** Frees a condition variable. Found in #DBusThreadFunctions. 79 */ 80 typedef void (* DBusCondVarFreeFunction) (DBusCondVar *cond); 81 82 /** Waits on a condition variable. Found in 83 * #DBusThreadFunctions. Must work with either a recursive or 84 * nonrecursive mutex, whichever the thread implementation 85 * provides. Note that PTHREAD_MUTEX_RECURSIVE does not work with 86 * condition variables (does not save/restore the recursion count) so 87 * don't try using simply pthread_cond_wait() and a 88 * PTHREAD_MUTEX_RECURSIVE to implement this, it won't work right. 89 * 90 * Has no error conditions. Must succeed if it returns. 91 */ 92 typedef void (* DBusCondVarWaitFunction) (DBusCondVar *cond, 93 DBusMutex *mutex); 94 95 /** Waits on a condition variable with a timeout. Found in 96 * #DBusThreadFunctions. Returns #TRUE if the wait did not 97 * time out, and #FALSE if it did. 98 * 99 * Has no error conditions. Must succeed if it returns. 100 */ 101 typedef dbus_bool_t (* DBusCondVarWaitTimeoutFunction) (DBusCondVar *cond, 102 DBusMutex *mutex, 103 int timeout_milliseconds); 104 /** Wakes one waiting thread on a condition variable. Found in #DBusThreadFunctions. 105 * 106 * Has no error conditions. Must succeed if it returns. 107 */ 108 typedef void (* DBusCondVarWakeOneFunction) (DBusCondVar *cond); 109 110 /** Wakes all waiting threads on a condition variable. Found in #DBusThreadFunctions. 111 * 112 * Has no error conditions. Must succeed if it returns. 113 */ 114 typedef void (* DBusCondVarWakeAllFunction) (DBusCondVar *cond); 115 116 /** 117 * Flags indicating which functions are present in #DBusThreadFunctions. Used to allow 118 * the library to detect older callers of dbus_threads_init() if new possible functions 119 * are added to #DBusThreadFunctions. 120 */ 121 typedef enum 122 { 123 DBUS_THREAD_FUNCTIONS_MUTEX_NEW_MASK = 1 << 0, 124 DBUS_THREAD_FUNCTIONS_MUTEX_FREE_MASK = 1 << 1, 125 DBUS_THREAD_FUNCTIONS_MUTEX_LOCK_MASK = 1 << 2, 126 DBUS_THREAD_FUNCTIONS_MUTEX_UNLOCK_MASK = 1 << 3, 127 DBUS_THREAD_FUNCTIONS_CONDVAR_NEW_MASK = 1 << 4, 128 DBUS_THREAD_FUNCTIONS_CONDVAR_FREE_MASK = 1 << 5, 129 DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_MASK = 1 << 6, 130 DBUS_THREAD_FUNCTIONS_CONDVAR_WAIT_TIMEOUT_MASK = 1 << 7, 131 DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ONE_MASK = 1 << 8, 132 DBUS_THREAD_FUNCTIONS_CONDVAR_WAKE_ALL_MASK = 1 << 9, 133 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_NEW_MASK = 1 << 10, 134 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_FREE_MASK = 1 << 11, 135 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_LOCK_MASK = 1 << 12, 136 DBUS_THREAD_FUNCTIONS_RECURSIVE_MUTEX_UNLOCK_MASK = 1 << 13, 137 DBUS_THREAD_FUNCTIONS_ALL_MASK = (1 << 14) - 1 138 } DBusThreadFunctionsMask; 139 140 /** 141 * Functions that must be implemented to make the D-Bus library 142 * thread-aware. The recursive mutex functions should be specified 143 * rather than the old, deprecated nonrecursive ones. 144 * 145 * The condition variable functions have to work with recursive 146 * mutexes if you provide those, or with nonrecursive mutexes if you 147 * provide those. 148 * 149 * If implementing threads using pthreads, be aware that 150 * PTHREAD_MUTEX_RECURSIVE is broken in combination with condition 151 * variables. libdbus relies on the Java-style behavior that when 152 * waiting on a condition, the recursion count is saved and restored, 153 * and the mutex is completely unlocked, not just decremented one 154 * level of recursion. 155 * 156 * Thus with pthreads you probably have to roll your own emulated 157 * recursive mutexes, you can't use PTHREAD_MUTEX_RECURSIVE. This is 158 * what dbus_threads_init_default() does on platforms that use 159 * pthreads. 160 */ 161 typedef struct 162 { 163 unsigned int mask; /**< Mask indicating which functions are present. */ 164 165 DBusMutexNewFunction mutex_new; /**< Function to create a mutex; optional and deprecated. */ 166 DBusMutexFreeFunction mutex_free; /**< Function to free a mutex; optional and deprecated. */ 167 DBusMutexLockFunction mutex_lock; /**< Function to lock a mutex; optional and deprecated. */ 168 DBusMutexUnlockFunction mutex_unlock; /**< Function to unlock a mutex; optional and deprecated. */ 169 170 DBusCondVarNewFunction condvar_new; /**< Function to create a condition variable */ 171 DBusCondVarFreeFunction condvar_free; /**< Function to free a condition variable */ 172 DBusCondVarWaitFunction condvar_wait; /**< Function to wait on a condition */ 173 DBusCondVarWaitTimeoutFunction condvar_wait_timeout; /**< Function to wait on a condition with a timeout */ 174 DBusCondVarWakeOneFunction condvar_wake_one; /**< Function to wake one thread waiting on the condition */ 175 DBusCondVarWakeAllFunction condvar_wake_all; /**< Function to wake all threads waiting on the condition */ 176 177 DBusRecursiveMutexNewFunction recursive_mutex_new; /**< Function to create a recursive mutex */ 178 DBusRecursiveMutexFreeFunction recursive_mutex_free; /**< Function to free a recursive mutex */ 179 DBusRecursiveMutexLockFunction recursive_mutex_lock; /**< Function to lock a recursive mutex */ 180 DBusRecursiveMutexUnlockFunction recursive_mutex_unlock; /**< Function to unlock a recursive mutex */ 181 182 void (* padding1) (void); /**< Reserved for future expansion */ 183 void (* padding2) (void); /**< Reserved for future expansion */ 184 void (* padding3) (void); /**< Reserved for future expansion */ 185 void (* padding4) (void); /**< Reserved for future expansion */ 186 187 } DBusThreadFunctions; 188 189 DBUS_EXPORT 190 dbus_bool_t dbus_threads_init (const DBusThreadFunctions *functions); 191 DBUS_EXPORT 192 dbus_bool_t dbus_threads_init_default (void); 193 194 /** @} */ 195 196 DBUS_END_DECLS 197 198 #endif /* DBUS_THREADS_H */ 199