1 files changed, 57 insertions, 0 deletions
diff --git a/externals/mysql/atomic/rwlock.h b/externals/mysql/atomic/rwlock.h
new file mode 100644
index 00000000000..9e81657a90c
--- /dev/null
+++ b/externals/mysql/atomic/rwlock.h
@@ -0,0 +1,57 @@
+/* Copyright (C) 2006 MySQL AB
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+typedef struct {pthread_mutex_t rw;} my_atomic_rwlock_t;
+#define MY_ATOMIC_MODE_RWLOCKS 1
+
+#ifdef MY_ATOMIC_MODE_DUMMY
+/*
+  the following can never be enabled by ./configure, one need to put #define in
+  a source to trigger the following warning. The resulting code will be broken,
+  it only makes sense to do it to see now test_atomic detects broken
+  implementations (another way is to run a UP build on an SMP box).
+*/
+#warning MY_ATOMIC_MODE_DUMMY and MY_ATOMIC_MODE_RWLOCKS are incompatible
+#define my_atomic_rwlock_destroy(name)
+#define my_atomic_rwlock_init(name)
+#define my_atomic_rwlock_rdlock(name)
+#define my_atomic_rwlock_wrlock(name)
+#define my_atomic_rwlock_rdunlock(name)
+#define my_atomic_rwlock_wrunlock(name)
+#define MY_ATOMIC_MODE "dummy (non-atomic)"
+#else
+/*
+  we're using read-write lock macros but map them to mutex locks, and they're
+  faster. Still, having semantically rich API we can change the
+  underlying implementation, if necessary.
+*/
+#define my_atomic_rwlock_destroy(name)     pthread_mutex_destroy(& (name)->rw)
+#define my_atomic_rwlock_init(name)        pthread_mutex_init(& (name)->rw, 0)
+#define my_atomic_rwlock_rdlock(name)      pthread_mutex_lock(& (name)->rw)
+#define my_atomic_rwlock_wrlock(name)      pthread_mutex_lock(& (name)->rw)
+#define my_atomic_rwlock_rdunlock(name)    pthread_mutex_unlock(& (name)->rw)
+#define my_atomic_rwlock_wrunlock(name)    pthread_mutex_unlock(& (name)->rw)
+#define MY_ATOMIC_MODE "mutex"
+#ifndef MY_ATOMIC_MODE_RWLOCKS
+#define MY_ATOMIC_MODE_RWLOCKS 1
+#endif
+#endif
+
+#define make_atomic_add_body(S)     int ## S sav; sav= *a; *a+= v; v=sav;
+#define make_atomic_fas_body(S)     int ## S sav; sav= *a; *a= v; v=sav;
+#define make_atomic_cas_body(S)     if ((ret= (*a == *cmp))) *a= set; else *cmp=*a;
+#define make_atomic_load_body(S)    ret= *a;
+#define make_atomic_store_body(S)   *a= v;
+