objc4-371.tar.gz

[apple/objc4.git] / runtime / objc-lockdebug.m

diff --git a/runtime/objc-lockdebug.m b/runtime/objc-lockdebug.m
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+/*
+ * Copyright (c) 2007 Apple Inc.  All Rights Reserved.
+ * 
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+/***********************************************************************
+* objc-lock.m
+* Error-checking locks for debugging.
+**********************************************************************/
+
+#import "objc-private.h"
+
+typedef struct _objc_lock_list {
+    int allocated;
+    int used;
+    mutex_t list[0];  // variable-size
+} _objc_lock_list;
+
+static struct _objc_lock_list *
+getLocks(BOOL create)
+{
+    _objc_pthread_data *data;
+    _objc_lock_list *locks;
+
+    data = _objc_fetch_pthread_data(create);
+    if (!data  &&  !create) return NULL;
+
+    locks = data->lockList;
+    if (!locks) {
+        if (!create) {
+            return NULL;
+        } else {
+            locks = _calloc_internal(1, sizeof(_objc_lock_list) + sizeof(mutex_t) * 4);
+            locks->allocated = 4;
+            locks->used = 0;
+            data->lockList = locks;
+        }
+    }
+
+    if (locks->allocated == locks->used) {
+        if (!create) {
+            return locks;
+        } else {
+            data->lockList = _calloc_internal(1, sizeof(_objc_lock_list) + 2 * locks->used * sizeof(mutex_t));
+            data->lockList->used = locks->used;
+            data->lockList->allocated = locks->used * 2;
+            memcpy(data->lockList->list, locks->list, locks->used * sizeof(mutex_t));
+            _free_internal(locks);
+            locks = data->lockList;
+        }
+    }
+
+    return locks;
+}
+
+
+static BOOL 
+hasLock(_objc_lock_list *locks, mutex_t lock)
+{
+    int i;
+    if (!locks) return NO;
+    
+    for (i = 0; i < locks->used; i++) {
+        if (locks->list[i] == lock) return YES;
+    }
+    return NO;
+}
+
+
+static void 
+setLock(_objc_lock_list *locks, mutex_t lock)
+{
+    locks->list[locks->used++] = lock;
+}
+
+static void 
+clearLock(_objc_lock_list *locks, mutex_t lock)
+{
+    int i;
+    for (i = 0; i < locks->used; i++) {
+        if (locks->list[i] == lock) {
+            locks->list[i] = locks->list[--locks->used];
+            return;
+        }
+    }
+}
+
+
+__private_extern__ void 
+_lock_debug(mutex_t lock, const char *name)
+{
+    _objc_lock_list *locks = getLocks(YES);
+    if (hasLock(locks, lock)) _objc_fatal("deadlock: relocking %s\n", name+1);
+    setLock(locks, lock);
+    mutex_lock(lock);
+}
+
+
+__private_extern__ void 
+_checklock_debug(mutex_t lock, const char *name)
+{
+    _objc_lock_list *locks = getLocks(NO);
+    if (!hasLock(locks, lock)) _objc_fatal("%s incorrectly not held\n",name+1);
+}
+
+
+__private_extern__ void 
+_checkunlock_debug(mutex_t lock, const char *name)
+{
+    _objc_lock_list *locks = getLocks(NO);
+    if (hasLock(locks, lock)) _objc_fatal("%s incorrectly held\n", name+1);
+}
+
+
+__private_extern__ void 
+_unlock_debug(mutex_t lock, const char *name)
+{
+    _objc_lock_list *locks = getLocks(NO);
+    if (!hasLock(locks, lock)) _objc_fatal("unlocking unowned %s\n", name+1);
+    clearLock(locks, lock);
+    mutex_unlock(lock);
+}
+
+
+__private_extern__ void
+_destroyLockList(struct _objc_lock_list *locks)
+{
+    // fixme complain about any still-held locks?
+    if (locks) _free_internal(locks);
+}