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Fix several problems with lockWhenCondition:beforeDate:

Browse source 
First -- it needs to use timeIntervalSince1970 to be using the same reference date required for pthread_cond_timedwait
Second -- lockWhenCondition needs to loop because pthread_cond_timedwait can return prior to delay expiring (but with the wrong condition).
Third -- Internally the lock was incorrectly being unlocked on a delayed acquire (and YES return).  And was incorrectly being unlocked a second time when the timeout expired.

Also, fixed a problem with tryLockWhenCondition:
By calling lockWhenCondition: it would incorrectly report a deadlock (rather than just return no) when we already have the lock.

All these changes are in line with expected and documented behavior for NSLock.

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@29472 72102866-910b-0410-8b05-ffd578937521
This commit is contained in:
Jonathan Gillaspie 2010-02-03 21:15:03 +00:00
parent 367d552a3b
commit d85c001251
1 changed files with 29 additions and 20 deletions
Download patch file Download diff file Expand all files Collapse all files

49
Source/NSLock.m
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@ -297,23 +297,29 @@ MUNLOCK
- (BOOL) waitUntilDate: (NSDate*)limit - (BOOL) waitUntilDate: (NSDate*)limit
{ {
NSTimeInterval t = [limit timeIntervalSinceReferenceDate]; NSTimeInterval t = [limit timeIntervalSince1970];
double secs, subsecs; double secs, subsecs;
struct timespec timeout; struct timespec timeout;
int retVal = 0;
// Split the float into seconds and fractions of a second // Split the float into seconds and fractions of a second
subsecs = modf(t, &secs); subsecs = modf(t, &secs);
timeout.tv_sec = secs; timeout.tv_sec = secs;
// Convert fractions of a second to nanoseconds // Convert fractions of a second to nanoseconds
timeout.tv_nsec = subsecs * 1e9; timeout.tv_nsec = subsecs * 1e9;
if (0 == pthread_cond_timedwait(&_condition, &_mutex, &timeout))
retVal = pthread_cond_timedwait(&_condition, &_mutex, &timeout);
if (retVal == 0)
{ {
return YES; return YES;
} }
else else if (retVal == EINVAL)
{ {
return NO; NSLog(@"Invalid arguments to pthread_cond_timedwait");
} }
return NO;
} }
@end @end
@ -379,24 +385,19 @@ MUNLOCK
- (BOOL) lockWhenCondition: (NSInteger)condition_to_meet - (BOOL) lockWhenCondition: (NSInteger)condition_to_meet
beforeDate: (NSDate*)limitDate beforeDate: (NSDate*)limitDate
{ {
BOOL ret;
[_condition lock]; [_condition lock];
if (condition_to_meet == _condition_value) if (condition_to_meet == _condition_value)
{ {
return YES; return YES;
} }
if ([_condition waitUntilDate: limitDate] while ([_condition waitUntilDate: limitDate]) {
&& (condition_to_meet == _condition_value)) if (condition_to_meet == _condition_value) {
{ return YES; // KEEP THE LOCK
ret = YES;
} }
else }
{
ret = NO; // we timed out and no longer have the lock
} return NO;
[_condition unlock];
return ret;
} }
MNAME MNAME
@ -406,10 +407,18 @@ MNAME
return [_condition tryLock]; return [_condition tryLock];
} }
- (BOOL) tryLockWhenCondition: (NSInteger)value - (BOOL) tryLockWhenCondition: (NSInteger)condition_to_meet
{ {
return [self lockWhenCondition: value if ([_condition tryLock]) {
beforeDate: [NSDate date]]; if (condition_to_meet == _condition_value) {
return YES; // KEEP THE LOCK
}
else {
[_condition unlock];
}
}
return NO;
} }
- (void) unlock - (void) unlock