1 /* Copyright (C) 2007-2008 The Android Open Source Project 2 ** 3 ** This software is licensed under the terms of the GNU General Public 4 ** License version 2, as published by the Free Software Foundation, and 5 ** may be copied, distributed, and modified under those terms. 6 ** 7 ** This program is distributed in the hope that it will be useful, 8 ** but WITHOUT ANY WARRANTY; without even the implied warranty of 9 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 10 ** GNU General Public License for more details. 11 */ 12 13 #ifndef _ANDROID_UTILS_FILELOCK_H 14 #define _ANDROID_UTILS_FILELOCK_H 15 16 /** FILE LOCKS SUPPORT 17 ** 18 ** a FileLock is useful to prevent several emulator instances from using the same 19 ** writable file (e.g. the userdata.img disk images). 20 ** 21 ** create a FileLock object with filelock_create(), the function will return 22 ** NULL only if the corresponding path is already locked by another emulator 23 ** of if the path is read-only. 24 ** 25 ** note that 'path' can designate a non-existing path and that the lock creation 26 ** function can detect stale file locks that can longer when the emulator 27 ** crashes unexpectedly, and will happily clean them for you. 28 ** 29 ** you can call filelock_release() to release a file lock explicitely. otherwise 30 ** all file locks are automatically released when the program exits. 31 **/ 32 33 typedef struct FileLock FileLock; 34 35 extern FileLock* filelock_create ( const char* path ); 36 extern void filelock_release( FileLock* lock ); 37 38 #endif /* _ANDROID_UTILS_FILELOCK_H */ 39
