The helper class for asynchronous wait with timeout and simple signal.

HTWait.h

#import <Foundation/Foundation.h>

@interface HTWait : NSObject
{
  BOOL signaled;
}

- (void)prepare;
- (void)signal;
- (void)waitForTimeout:(NSTimeInterval)timeOut;

@end

HTWait.m

#import "HTWait.h"

@implementation HTWait

- (void)prepare
{
  signaled = NO;
}

- (void)signal
{
  @synchronized(self) {
    signaled = YES;
  }
}

- (void)waitForTimeout:(NSTimeInterval)timeOut
{
  NSDate* untilDate = [NSDate dateWithTimeIntervalSinceNow:timeOut];
  NSTimeInterval timeInterval = 0.05;
  while (signaled == NO)
  {
    if (![[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate dateWithTimeIntervalSinceNow:timeInterval]])
    {
      [NSThread sleepForTimeInterval:timeInterval];
    }
    if ([untilDate compare:[NSDate date]] == NSOrderedAscending)
      break;
  }
}

@end