| 1 | /* Read-write locks (native Windows implementation). |
| 2 | Copyright (C) 2005-2020 Free Software Foundation, Inc. |
| 3 | |
| 4 | This program is free software; you can redistribute it and/or modify |
| 5 | it under the terms of the GNU General Public License as published by |
| 6 | the Free Software Foundation; either version 3, or (at your option) |
| 7 | any later version. |
| 8 | |
| 9 | This program is distributed in the hope that it will be useful, |
| 10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | GNU General Public License for more details. |
| 13 | |
| 14 | You should have received a copy of the GNU General Public License |
| 15 | along with this program; if not, see <https://www.gnu.org/licenses/>. */ |
| 16 | |
| 17 | /* Written by Bruno Haible <bruno@clisp.org>, 2005. |
| 18 | Based on GCC's gthr-win32.h. */ |
| 19 | |
| 20 | #ifndef _WINDOWS_RWLOCK_H |
| 21 | #define _WINDOWS_RWLOCK_H |
| 22 | |
| 23 | #define WIN32_LEAN_AND_MEAN /* avoid including junk */ |
| 24 | #include <windows.h> |
| 25 | |
| 26 | #include "windows-initguard.h" |
| 27 | |
| 28 | /* It is impossible to implement read-write locks using plain locks, without |
| 29 | introducing an extra thread dedicated to managing read-write locks. |
| 30 | Therefore here we need to use the low-level Event type. */ |
| 31 | |
| 32 | typedef struct |
| 33 | { |
| 34 | HANDLE *array; /* array of waiting threads, each represented by an event */ |
| 35 | unsigned int count; /* number of waiting threads */ |
| 36 | unsigned int alloc; /* length of allocated array */ |
| 37 | unsigned int offset; /* index of first waiting thread in array */ |
| 38 | } |
| 39 | glwthread_carray_waitqueue_t; |
| 40 | typedef struct |
| 41 | { |
| 42 | glwthread_initguard_t guard; /* protects the initialization */ |
| 43 | CRITICAL_SECTION lock; /* protects the remaining fields */ |
| 44 | glwthread_carray_waitqueue_t waiting_readers; /* waiting readers */ |
| 45 | glwthread_carray_waitqueue_t waiting_writers; /* waiting writers */ |
| 46 | int runcount; /* number of readers running, or -1 when a writer runs */ |
| 47 | } |
| 48 | glwthread_rwlock_t; |
| 49 | |
| 50 | #define GLWTHREAD_RWLOCK_INIT { GLWTHREAD_INITGUARD_INIT } |
| 51 | |
| 52 | #ifdef __cplusplus |
| 53 | extern "C" { |
| 54 | #endif |
| 55 | |
| 56 | extern void glwthread_rwlock_init (glwthread_rwlock_t *lock); |
| 57 | extern int glwthread_rwlock_rdlock (glwthread_rwlock_t *lock); |
| 58 | extern int glwthread_rwlock_wrlock (glwthread_rwlock_t *lock); |
| 59 | extern int glwthread_rwlock_tryrdlock (glwthread_rwlock_t *lock); |
| 60 | extern int glwthread_rwlock_trywrlock (glwthread_rwlock_t *lock); |
| 61 | extern int glwthread_rwlock_unlock (glwthread_rwlock_t *lock); |
| 62 | extern int glwthread_rwlock_destroy (glwthread_rwlock_t *lock); |
| 63 | |
| 64 | #ifdef __cplusplus |
| 65 | } |
| 66 | #endif |
| 67 | |
| 68 | #endif /* _WINDOWS_RWLOCK_H */ |