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* Source/NSLock.m
* Headers/Foundation/NSLock.h Completely rewritten implementations of NSLock.h classes. These are now faster, more complete, OS X-compatible, and most importantly actually work. The old ones, for example, called functions that were not implemented on Windows. * Source/NSThread.m Call pthread functions directly in NSThread instead of via the libobjc abstraction layer. Also fixed a few issues, such as GC not being initialized properly for NSThread subclasses that override -main (Javaism supported by OS X) and tidies up the code in several places, removing premature optimizations, especially those that introduce a test for an unlikely case at the start of a method and thus slow everything down. As a result of this change, GNUstep now depends on an implementation of POSIX threads. This is included as standard on all modern UNIX systems, and as an option on less-modern UNIX systems and non-UNIX systems, including Windows. If you are building GNUstep on Windows, please install the pthreads-win32 package, available from: http://sourceware.org/pthreads-win32/ PLEASE TEST THIS! There may be some code that depended on the old behaviour. I have been running the new NSLock implementation on FreeBSD for a few weeks without issue; please report to me any problems that you have on your platform. git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@28598 72102866-910b-0410-8b05-ffd578937521
This commit is contained in:
David Chisnall
parent
9f5f6bc382
commit
d7a877b871
4 changed files with 458 additions and 920 deletions
866
Source/NSLock.m
866
Source/NSLock.m
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@ -1,11 +1,7 @@
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/** Mutual exclusion locking classes
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Copyright (C) 1996,2003 Free Software Foundation, Inc.
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/** Control of executable units within a shared virtual memory space
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Copyright (C) 1996-2000 Free Software Foundation, Inc.
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Author: Scott Christley <scottc@net-community.com>
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Created: 1996
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Author: Richard Frith-Macdonald <rfm@gnu.org>
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This file is part of the GNUstep Objective-C Library.
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Original Author: David Chisnall <csdavec@swan.ac.uk>
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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@ -23,723 +19,303 @@
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Boston, MA 02111 USA.
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<title>NSLock class reference</title>
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$Date$ $Revision$
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*/
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#include "config.h"
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#include <errno.h>
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#include "GNUstepBase/preface.h"
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// This file uses some SUS'98 extensions, so we need to tell glibc not to hide
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// them. Other platforms have more sensible libcs, which just default to being
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// standards-compliant.
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#define _XOPEN_SOURCE 500
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#include "Foundation/NSLock.h"
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#include <math.h>
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#include <errno.h>
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#include "Foundation/NSException.h"
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#include "Foundation/NSDebug.h"
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#include "Foundation/NSThread.h"
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#ifdef NeXT_RUNTIME
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#include "thr-mach.h"
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#endif
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#define _MUTEX ((objc_mutex_t)_mutex)
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#define _CONDITION ((objc_condition_t)_condition)
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/**
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* Methods shared between NSLock, NSRecursiveLock, and NSCondition
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*
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* Note: These methods currently throw exceptions when locks are incorrectly
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* acquired. This is compatible with earlier GNUstep behaviour. In OS X 10.5
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* and later, these will just NSLog a warning instead. Throwing an exception
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* is probably better behaviour, because it encourages developer to fix their
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* code.
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*/
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#define NSLOCKING_METHODS \
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- (void)lock\
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{\
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int err = pthread_mutex_lock(&_mutex);\
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if (EINVAL == err)\
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{\
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[NSException raise: NSLockException\
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format: @"failed to unlock mutex"];\
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}\
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if (EDEADLK == err)\
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{\
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_NSLockError(self, _cmd);\
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}\
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}\
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- (void)unlock\
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{\
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if (0 != pthread_mutex_unlock(&_mutex))\
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{\
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[NSException raise: NSLockException\
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format: @"failed to unlock mutex"];\
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}\
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}\
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- (NSString*) description\
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{\
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if (_name == nil)\
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{\
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return [super description];\
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}\
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return [NSString stringWithFormat: @"%@ '%@'",\
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[super description], _name];\
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}\
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- (BOOL) tryLock\
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{\
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int err = pthread_mutex_trylock(&_mutex);\
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if (EDEADLK == err)\
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{\
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_NSLockError(self, _cmd);\
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return YES;\
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}\
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return (0 == err);\
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}\
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- (BOOL) lockBeforeDate: (NSDate*)limit\
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{\
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do\
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{\
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int err = pthread_mutex_trylock(&_mutex);\
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if (EDEADLK == err)\
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{\
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_NSLockError(self, _cmd);\
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return YES;\
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}\
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if (0 == err)\
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{\
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return YES;\
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}\
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sched_yield();\
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} while([limit timeIntervalSinceNow] < 0);\
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return NO;\
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}\
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NAME_METHODS
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extern void GSSleepUntilIntervalSinceReferenceDate(NSTimeInterval);
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extern NSTimeInterval GSTimeNow();
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typedef struct {
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NSTimeInterval end;
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NSTimeInterval i0;
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NSTimeInterval i1;
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NSTimeInterval max;
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} GSSleepInfo;
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static void GSSleepInit(NSDate *limit, GSSleepInfo *context)
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{
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context->end = [limit timeIntervalSinceReferenceDate];
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context->i0 = 0.0;
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context->i1 = 0.0001; // Initial pause interval.
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context->max = 0.25; // Maximum pause interval.
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#define NAME_METHODS \
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- (void)setName:(NSString*)newName\
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{\
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ASSIGNCOPY(_name, newName);\
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}\
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- (NSString*)name\
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{\
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return _name;\
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}
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/**
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* <p>Using a pointer to a context structure initialised using GSSleepInit()
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* we either pause for a while and return YES or, if the limit date
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* has passed, return NO.
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* </p>
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* <p>The pause intervals start off very small, but rapidly increase
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* (following a fibonacci sequence) up to a maximum value.
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* </p>
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* <p>We use the GSSleepUntilIntervalSinceReferenceDate() function to
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* avoid objc runtime messaging overheads and overheads of creating and
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* destroying temporary date objects.
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* </p>
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* OS X 10.5 compatibility function to allow debugging deadlock conditions.
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*
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* On OS X, this really deadlocks. For now, we just continue, while logging
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* the 'you are a numpty' warning.
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*/
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static BOOL GSSleepOrFail(GSSleepInfo *context)
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void _NSLockError(id obj, SEL _cmd)
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{
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NSTimeInterval when = GSTimeNow();
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NSTimeInterval tmp;
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NSLog(@"*** -[%@ %@]: deadlock (%@)", [obj class],
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NSStringFromSelector(_cmd), obj);
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NSLog(@"*** Break on _NSLockError() to debug.");
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}
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if (when >= context->end)
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{
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return NO;
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}
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tmp = context->i0 + context->i1;
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context->i0 = context->i1;
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context->i1 = tmp;
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if (tmp > context->max)
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{
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tmp = context->max;
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}
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when += tmp;
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if (when > context->end)
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{
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when = context->end;
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}
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GSSleepUntilIntervalSinceReferenceDate(when);
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return YES; // Paused.
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/**
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* Init method for an NSLock / NSRecursive lock. Creates a mutex of the
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* specified type. Also adds the corresponding -finalize and -dealloc methods.
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*/
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#define INIT_LOCK_WITH_TYPE(lock_type) \
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- (id) init\
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{\
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if (nil == (self = [super init])) { return nil; }\
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pthread_mutexattr_t attr;\
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pthread_mutexattr_init(&attr);\
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pthread_mutexattr_settype(&attr, lock_type);\
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if (0 != pthread_mutex_init(&_mutex, &attr))\
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{\
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[self release];\
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return nil;\
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}\
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return self;\
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}\
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- (void) finalize\
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{\
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pthread_mutex_destroy(&_mutex);\
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}\
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- (void) dealloc\
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{\
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[self finalize];\
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[_name release];\
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[super dealloc];\
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}
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// Exceptions
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NSString *NSLockException = @"NSLockException";
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NSString *NSConditionLockException = @"NSConditionLockException";
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NSString *NSRecursiveLockException = @"NSRecursiveLockException";
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// Macros
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#define CHECK_RECURSIVE_LOCK(mutex) \
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{ \
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if ((mutex)->owner == objc_thread_id()) \
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{ \
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[NSException \
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raise: NSLockException \
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format: @"Thread attempted to recursively lock"]; \
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/* NOT REACHED */ \
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} \
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}
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#define CHECK_RECURSIVE_CONDITION_LOCK(mutex) \
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{ \
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if ((mutex)->owner == objc_thread_id()) \
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{ \
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[NSException \
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raise: NSConditionLockException \
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format: @"Thread attempted to recursively lock"]; \
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/* NOT REACHED */ \
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} \
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}
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// NSLock class
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// Simplest lock for protecting critical sections of code
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/**
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* An <code>NSLock</code> is used in multi-threaded applications to protect
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* critical pieces of code. While one thread holds a lock within a piece of
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* code, another thread cannot execute that code until the first thread has
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* given up its hold on the lock. The limitation of <code>NSLock</code> is
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* that you can only lock an <code>NSLock</code> once and it must be unlocked
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* before it can be acquired again.<br /> Other lock classes, notably
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* [NSRecursiveLock], have different restrictions.
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*/
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@implementation NSLock
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// Designated initializer
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- (id) init
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{
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self = [super init];
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if (self != nil)
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{
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// Allocate the mutex from the runtime
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_mutex = objc_mutex_allocate();
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if (_mutex == 0)
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{
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RELEASE(self);
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NSLog(@"Failed to allocate a mutex");
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return nil;
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}
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}
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return self;
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}
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- (void) dealloc
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{
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[self finalize];
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[super dealloc];
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}
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- (NSString*) description
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{
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if (_name == nil)
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return [super description];
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return [NSString stringWithFormat: @"%@ named '%@'",
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[super description], _name];
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}
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- (void) finalize
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{
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if (_mutex != 0)
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{
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objc_mutex_t tmp = _MUTEX;
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_mutex = 0;
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// Ask the runtime to deallocate the mutex
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// If there are outstanding locks then it will block
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if (objc_mutex_deallocate(tmp) == -1)
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{
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NSWarnMLog(@"objc_mutex_deallocate() failed for %@", self);
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}
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}
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DESTROY(_name);
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}
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- (NSString*) name
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{
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return _name;
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}
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- (void) setName: (NSString*)name
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{
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ASSIGNCOPY(_name, name);
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}
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/**
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* Attempts to acquire a lock, but returns immediately if the lock
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* cannot be acquired. It returns YES if the lock is acquired. It returns
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* NO if the lock cannot be acquired or if the current thread already has
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* the lock.
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*/
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- (BOOL) tryLock
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{
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/* Return NO if we're already locked */
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if (_MUTEX->owner == objc_thread_id())
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{
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return NO;
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}
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// Ask the runtime to acquire a lock on the mutex
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if (objc_mutex_trylock(_MUTEX) == -1)
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{
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return NO;
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}
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return YES;
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}
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/**
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* Attempts to acquire a lock before the date limit passes. It returns YES
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* if it can. It returns NO if it cannot, or if the current thread already
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* has the lock (but it waits until the time limit is up before returning
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* NO).
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*/
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- (BOOL) lockBeforeDate: (NSDate*)limit
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{
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int x;
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GSSleepInfo ctxt;
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GSSleepInit(limit, &ctxt);
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/* This is really the behavior of OpenStep, if the current thread has
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the lock, we just block until the time limit is up. Very odd */
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while (_MUTEX->owner == objc_thread_id()
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|| (x = objc_mutex_trylock(_MUTEX)) == -1)
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{
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if (GSSleepOrFail(&ctxt) == NO)
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{
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return NO;
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}
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}
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return YES;
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}
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/**
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* Attempts to acquire a lock, and waits until it can do so.
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*/
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- (void) lock
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{
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CHECK_RECURSIVE_LOCK(_MUTEX);
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// Ask the runtime to acquire a lock on the mutex
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// This will block
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if (objc_mutex_lock(_MUTEX) == -1)
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{
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[NSException raise: NSLockException
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format: @"failed to lock mutex"];
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/* NOT REACHED */
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}
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}
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- (void) unlock
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{
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// Ask the runtime to release a lock on the mutex
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if (objc_mutex_unlock(_MUTEX) == -1)
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{
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[NSException raise: NSLockException
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format: @"unlock: failed to unlock mutex"];
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/* NOT REACHED */
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}
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}
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// Use an error-checking lock. This is marginally slower, but lets us throw
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// exceptions when incorrect locking occurs.
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INIT_LOCK_WITH_TYPE(PTHREAD_MUTEX_ERRORCHECK)
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NSLOCKING_METHODS
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@end
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// NSConditionLock
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// Allows locking and unlocking to be based upon an integer condition
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@implementation NSRecursiveLock
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INIT_LOCK_WITH_TYPE(PTHREAD_MUTEX_RECURSIVE);
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NSLOCKING_METHODS
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@end
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@implementation NSCondition
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- (id)init
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{
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if (nil == (self = [super init])) { return nil; }
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if (0 != pthread_cond_init(&_condition, NULL))
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{
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[self release];
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return nil;
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}
|
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if (0 != pthread_mutex_init(&_mutex, NULL))
|
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{
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pthread_cond_destroy(&_condition);
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[self release];
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return nil;
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}
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return self;
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}
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- (void)finalize
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{
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pthread_cond_destroy(&_condition);
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pthread_mutex_destroy(&_mutex);
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}
|
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- (void)dealloc
|
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{
|
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[self finalize];
|
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[_name release];
|
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[super dealloc];
|
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}
|
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- (void)wait
|
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{
|
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pthread_cond_wait(&_condition, &_mutex);
|
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}
|
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- (BOOL)waitUntilDate: (NSDate*)limit
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{
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NSTimeInterval t = [limit timeIntervalSinceReferenceDate];
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double secs, subsecs;
|
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struct timespec timeout;
|
||||
// Split the float into seconds and fractions of a second
|
||||
subsecs = modf(t, &secs);
|
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timeout.tv_sec = secs;
|
||||
// Convert fractions of a second to nanoseconds
|
||||
timeout.tv_nsec = subsecs * 1e9;
|
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return (0 == pthread_cond_timedwait(&_condition, &_mutex, &timeout));
|
||||
}
|
||||
- (void)signal
|
||||
{
|
||||
pthread_cond_signal(&_condition);
|
||||
}
|
||||
- (void)broadcast;
|
||||
{
|
||||
pthread_cond_broadcast(&_condition);
|
||||
}
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||||
NSLOCKING_METHODS
|
||||
@end
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||||
|
||||
@implementation NSConditionLock
|
||||
|
||||
- (id) init
|
||||
{
|
||||
return [self initWithCondition: 0];
|
||||
}
|
||||
|
||||
// Designated initializer
|
||||
// Initialize lock with condition
|
||||
- (id) initWithCondition: (NSInteger)value
|
||||
{
|
||||
self = [super init];
|
||||
if (self != nil)
|
||||
{
|
||||
_condition_value = value;
|
||||
|
||||
// Allocate the mutex from the runtime
|
||||
_condition = objc_condition_allocate ();
|
||||
if (_condition == 0)
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if (nil == (self = [super init])) { return nil; }
|
||||
if (nil == (_condition = [NSCondition new]))
|
||||
{
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||||
NSLog(@"Failed to allocate a condition");
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||||
RELEASE(self);
|
||||
return nil;
|
||||
[self release];
|
||||
return nil;
|
||||
}
|
||||
_mutex = objc_mutex_allocate ();
|
||||
if (_mutex == 0)
|
||||
{
|
||||
NSLog(@"Failed to allocate a mutex");
|
||||
RELEASE(self);
|
||||
return nil;
|
||||
}
|
||||
}
|
||||
return self;
|
||||
_condition_value = value;
|
||||
return self;
|
||||
}
|
||||
|
||||
- (void) dealloc
|
||||
{
|
||||
[self finalize];
|
||||
[_name release];
|
||||
[_condition release];
|
||||
[super dealloc];
|
||||
}
|
||||
|
||||
- (NSString*) description
|
||||
{
|
||||
if (_name == nil)
|
||||
return [super description];
|
||||
return [NSString stringWithFormat: @"%@ named '%@'",
|
||||
[super description], _name];
|
||||
}
|
||||
|
||||
- (void) finalize
|
||||
{
|
||||
if (_condition != 0)
|
||||
{
|
||||
objc_condition_t tmp = _CONDITION;
|
||||
|
||||
_condition = 0;
|
||||
// Ask the runtime to deallocate the condition
|
||||
if (objc_condition_deallocate(tmp) == -1)
|
||||
{
|
||||
NSWarnMLog(@"objc_condition_deallocate() failed for %@", self);
|
||||
}
|
||||
}
|
||||
if (_mutex != 0)
|
||||
{
|
||||
objc_mutex_t tmp = _MUTEX;
|
||||
|
||||
_mutex = 0;
|
||||
// Ask the runtime to deallocate the mutex
|
||||
// If there are outstanding locks then it will block
|
||||
if (objc_mutex_deallocate(tmp) == -1)
|
||||
{
|
||||
NSWarnMLog(@"objc_mutex_deallocate() failed for %@", self);
|
||||
}
|
||||
}
|
||||
DESTROY(_name);
|
||||
}
|
||||
|
||||
// Return the current condition of the lock
|
||||
- (NSInteger) condition
|
||||
{
|
||||
return _condition_value;
|
||||
}
|
||||
|
||||
// Acquiring and release the lock
|
||||
- (void) lockWhenCondition: (NSInteger)value
|
||||
{
|
||||
CHECK_RECURSIVE_CONDITION_LOCK(_MUTEX);
|
||||
|
||||
if (objc_mutex_lock(_MUTEX) == -1)
|
||||
{
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"lockWhenCondition: failed to lock mutex"];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
|
||||
while (_condition_value != value)
|
||||
{
|
||||
if (objc_condition_wait(_CONDITION, _MUTEX) == -1)
|
||||
{
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"objc_condition_wait failed"];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
- (NSString*) name
|
||||
{
|
||||
return _name;
|
||||
}
|
||||
|
||||
- (void) setName: (NSString*)name
|
||||
{
|
||||
ASSIGNCOPY(_name, name);
|
||||
[_condition lock];
|
||||
while (value != _condition_value)
|
||||
{
|
||||
[_condition wait];
|
||||
}
|
||||
}
|
||||
|
||||
- (void) unlockWithCondition: (NSInteger)value
|
||||
{
|
||||
int depth;
|
||||
|
||||
// First check to make sure we have the lock
|
||||
depth = objc_mutex_trylock(_MUTEX);
|
||||
|
||||
// Another thread has the lock so abort
|
||||
if (depth == -1)
|
||||
{
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"unlockWithCondition: Tried to unlock someone else's lock"];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
|
||||
// If the depth is only 1 then we just acquired
|
||||
// the lock above, bogus unlock so abort
|
||||
if (depth == 1)
|
||||
{
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"unlockWithCondition: Unlock attempted without lock"];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
|
||||
// This is a valid unlock so set the condition
|
||||
_condition_value = value;
|
||||
|
||||
// wake up blocked threads
|
||||
if (objc_condition_broadcast(_CONDITION) == -1)
|
||||
{
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"unlockWithCondition: objc_condition_broadcast failed"];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
|
||||
// and unlock twice
|
||||
if ((objc_mutex_unlock(_MUTEX) == -1)
|
||||
|| (objc_mutex_unlock(_MUTEX) == -1))
|
||||
{
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"unlockWithCondition: failed to unlock mutex"];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
}
|
||||
|
||||
- (BOOL) tryLock
|
||||
{
|
||||
if ((_MUTEX)->owner == objc_thread_id())
|
||||
{
|
||||
NSDebugLog(@"WARNING: Thread attempted to recursively tryLock : %@", self);
|
||||
return NO;
|
||||
}
|
||||
// Ask the runtime to acquire a lock on the mutex
|
||||
if (objc_mutex_trylock(_MUTEX) == -1)
|
||||
return NO;
|
||||
else
|
||||
return YES;
|
||||
[_condition lock];
|
||||
_condition_value = value;
|
||||
[_condition broadcast];
|
||||
[_condition unlock];
|
||||
}
|
||||
|
||||
- (BOOL) tryLockWhenCondition: (NSInteger)value
|
||||
{
|
||||
// tryLock message will check for recursive locks
|
||||
|
||||
// First can we even get the lock?
|
||||
if (![self tryLock])
|
||||
return NO;
|
||||
|
||||
// If we got the lock is it the right condition?
|
||||
if (_condition_value == value)
|
||||
return YES;
|
||||
else
|
||||
{
|
||||
// Wrong condition so release the lock
|
||||
[self unlock];
|
||||
return NO;
|
||||
}
|
||||
return [self lockWhenCondition: value
|
||||
beforeDate: [NSDate date]];
|
||||
}
|
||||
|
||||
// Acquiring the lock with a date condition
|
||||
- (BOOL) lockBeforeDate: (NSDate*)limit
|
||||
{
|
||||
GSSleepInfo ctxt;
|
||||
|
||||
CHECK_RECURSIVE_CONDITION_LOCK(_MUTEX);
|
||||
|
||||
GSSleepInit(limit, &ctxt);
|
||||
|
||||
while (objc_mutex_trylock(_MUTEX) == -1)
|
||||
{
|
||||
if (GSSleepOrFail(&ctxt) == NO)
|
||||
{
|
||||
return NO;
|
||||
}
|
||||
}
|
||||
return YES;
|
||||
return [_condition lockBeforeDate: limit];
|
||||
}
|
||||
|
||||
|
||||
- (BOOL) lockWhenCondition: (NSInteger)condition_to_meet
|
||||
beforeDate: (NSDate*)limitDate
|
||||
{
|
||||
#ifndef HAVE_OBJC_CONDITION_TIMEDWAIT
|
||||
GSSleepInfo ctxt;
|
||||
|
||||
CHECK_RECURSIVE_CONDITION_LOCK(_MUTEX);
|
||||
|
||||
GSSleepInit(limitDate, &ctxt);
|
||||
|
||||
do
|
||||
{
|
||||
if (_condition_value == condition_to_meet)
|
||||
[_condition lock];
|
||||
if (condition_to_meet == _condition_value)
|
||||
{
|
||||
while (objc_mutex_trylock(_MUTEX) == -1)
|
||||
{
|
||||
if (GSSleepOrFail(&ctxt) == NO)
|
||||
{
|
||||
return NO;
|
||||
}
|
||||
}
|
||||
if (_condition_value == condition_to_meet)
|
||||
{
|
||||
return YES;
|
||||
}
|
||||
if (objc_mutex_unlock(_MUTEX) == -1)
|
||||
{
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"%s failed to unlock mutex",
|
||||
GSNameFromSelector(_cmd)];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
return YES;
|
||||
}
|
||||
}
|
||||
while (GSSleepOrFail(&ctxt) == YES);
|
||||
|
||||
return NO;
|
||||
|
||||
#else
|
||||
NSTimeInterval atimeinterval;
|
||||
struct timespec endtime;
|
||||
|
||||
CHECK_RECURSIVE_CONDITION_LOCK(_MUTEX);
|
||||
|
||||
if (-1 == objc_mutex_lock(_MUTEX))
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"lockWhenCondition: failed to lock mutex"];
|
||||
|
||||
if (_condition_value == condition_to_meet)
|
||||
return YES;
|
||||
|
||||
atimeinterval = [limitDate timeIntervalSince1970];
|
||||
endtime.tv_sec =(NSUInteger)atimeinterval; // 941883028;//
|
||||
endtime.tv_nsec = (NSUInteger)((atimeinterval - (float)endtime.tv_sec)
|
||||
* 1000000000.0);
|
||||
|
||||
while (_condition_value != condition_to_meet)
|
||||
{
|
||||
switch (objc_condition_timedwait(_CONDITION, _MUTEX, &endtime))
|
||||
if ([_condition waitUntilDate: limitDate]
|
||||
&&
|
||||
(condition_to_meet == _condition_value))
|
||||
{
|
||||
case 0:
|
||||
break;
|
||||
case EINTR:
|
||||
break;
|
||||
case ETIMEDOUT :
|
||||
[self unlock];
|
||||
return NO;
|
||||
default:
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"objc_condition_timedwait failed"];
|
||||
[self unlock];
|
||||
return NO;
|
||||
return YES;
|
||||
}
|
||||
}
|
||||
return YES;
|
||||
#endif /* HAVE__OBJC_CONDITION_TIMEDWAIT */
|
||||
return NO;
|
||||
}
|
||||
|
||||
// NSLocking protocol
|
||||
// These methods ignore the condition
|
||||
// NSLocking methods. These aren't instantiated with the macro as they are
|
||||
// delegated to the NSCondition.
|
||||
- (void) lock
|
||||
{
|
||||
CHECK_RECURSIVE_CONDITION_LOCK(_MUTEX);
|
||||
|
||||
// Ask the runtime to acquire a lock on the mutex
|
||||
// This will block
|
||||
if (objc_mutex_lock(_MUTEX) == -1)
|
||||
{
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"lock: failed to lock mutex"];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
[_condition lock];
|
||||
}
|
||||
|
||||
- (void) unlock
|
||||
{
|
||||
// wake up blocked threads
|
||||
if (objc_condition_broadcast(_CONDITION) == -1)
|
||||
{
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"unlockWithCondition: objc_condition_broadcast failed"];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
|
||||
// Ask the runtime to release a lock on the mutex
|
||||
if (objc_mutex_unlock(_MUTEX) == -1)
|
||||
{
|
||||
[NSException raise: NSConditionLockException
|
||||
format: @"unlock: failed to unlock mutex"];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
[_condition unlock];
|
||||
}
|
||||
|
||||
@end
|
||||
|
||||
|
||||
|
||||
/**
|
||||
* See [NSLock] for more information about what a lock is. A recursive
|
||||
* lock extends [NSLock] in that you can lock a recursive lock multiple
|
||||
* times. Each lock must be balanced by a corresponding unlock, and the
|
||||
* lock is not released for another thread to acquire until the last
|
||||
* unlock call is made (corresponding to the first lock message).
|
||||
*/
|
||||
@implementation NSRecursiveLock
|
||||
|
||||
/** <init />
|
||||
*/
|
||||
- (id) init
|
||||
{
|
||||
self = [super init];
|
||||
if (self != nil)
|
||||
{
|
||||
// Allocate the mutex from the runtime
|
||||
_mutex = objc_mutex_allocate();
|
||||
if (_mutex == 0)
|
||||
{
|
||||
NSLog(@"Failed to allocate a mutex");
|
||||
RELEASE(self);
|
||||
return nil;
|
||||
}
|
||||
}
|
||||
return self;
|
||||
}
|
||||
|
||||
- (void) dealloc
|
||||
{
|
||||
[self finalize];
|
||||
[super dealloc];
|
||||
}
|
||||
|
||||
- (NSString*) description
|
||||
{
|
||||
if (_name == nil)
|
||||
return [super description];
|
||||
return [NSString stringWithFormat: @"%@ named '%@'",
|
||||
[super description], _name];
|
||||
}
|
||||
|
||||
- (void) finalize
|
||||
{
|
||||
if (_mutex != 0)
|
||||
{
|
||||
objc_mutex_t tmp = _MUTEX;
|
||||
|
||||
_mutex = 0;
|
||||
// Ask the runtime to deallocate the mutex
|
||||
// If there are outstanding locks then it will block
|
||||
if (objc_mutex_deallocate(tmp) == -1)
|
||||
{
|
||||
NSWarnMLog(@"objc_mutex_deallocate() failed for %@", self);
|
||||
}
|
||||
}
|
||||
DESTROY(_name);
|
||||
}
|
||||
|
||||
- (NSString*) name
|
||||
{
|
||||
return _name;
|
||||
}
|
||||
|
||||
- (void) setName: (NSString*)name
|
||||
{
|
||||
ASSIGNCOPY(_name, name);
|
||||
}
|
||||
|
||||
/**
|
||||
* Attempts to acquire a lock, but returns NO immediately if the lock
|
||||
* cannot be acquired. It returns YES if the lock is acquired. Can be
|
||||
* called multiple times to make nested locks.
|
||||
*/
|
||||
- (BOOL) tryLock
|
||||
{
|
||||
// Ask the runtime to acquire a lock on the mutex
|
||||
if (objc_mutex_trylock(_MUTEX) == -1)
|
||||
return NO;
|
||||
else
|
||||
return YES;
|
||||
return [_condition tryLock];
|
||||
}
|
||||
|
||||
/**
|
||||
* Attempts to acquire a lock before the date limit passes. It returns
|
||||
* YES if it can. It returns NO if it cannot
|
||||
* (but it waits until the time limit is up before returning NO).
|
||||
*/
|
||||
- (BOOL) lockBeforeDate: (NSDate*)limit
|
||||
{
|
||||
GSSleepInfo ctxt;
|
||||
|
||||
GSSleepInit(limit, &ctxt);
|
||||
while (objc_mutex_trylock(_MUTEX) == -1)
|
||||
{
|
||||
if (GSSleepOrFail(&ctxt) == NO)
|
||||
{
|
||||
return NO;
|
||||
}
|
||||
}
|
||||
return YES;
|
||||
}
|
||||
|
||||
// NSLocking protocol
|
||||
- (void) lock
|
||||
{
|
||||
// Ask the runtime to acquire a lock on the mutex
|
||||
// This will block
|
||||
if (objc_mutex_lock(_MUTEX) == -1)
|
||||
{
|
||||
[NSException raise: NSRecursiveLockException
|
||||
format: @"lock: failed to lock mutex"];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
}
|
||||
|
||||
- (void) unlock
|
||||
{
|
||||
// Ask the runtime to release a lock on the mutex
|
||||
if (objc_mutex_unlock(_MUTEX) == -1)
|
||||
{
|
||||
[NSException raise: NSRecursiveLockException
|
||||
format: @"unlock: failed to unlock mutex"];
|
||||
/* NOT REACHED */
|
||||
}
|
||||
}
|
||||
|
||||
NAME_METHODS
|
||||
@end
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue