keychain/ckks/CKKSCondition.m

   1 /*
   2  * Copyright (c) 2017 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #import "keychain/ckks/CKKSCondition.h"
  25
  26 @interface CKKSCondition ()
  27 @property dispatch_semaphore_t semaphore;
  28 @property CKKSCondition* chain;
  29 @end
  30
  31 @implementation CKKSCondition
  32
  33 -(instancetype)init {
  34     return [self initToChain:nil];
  35 }
  36
  37 -(instancetype)initToChain:(CKKSCondition*)chain
  38 {
  39     if((self = [super init])) {
  40         _semaphore = dispatch_semaphore_create(0);
  41         _chain = chain;
  42     }
  43     return self;
  44 }
  45
  46 -(void)fulfill {
  47     dispatch_semaphore_signal(self.semaphore);
  48     [self.chain fulfill];
  49     self.chain = nil; // break the retain, since that condition is filled
  50 }
  51
  52 -(long)wait:(uint64_t)timeout {
  53     long result = dispatch_semaphore_wait(self.semaphore, dispatch_time(DISPATCH_TIME_NOW, timeout));
  54
  55     // If we received a go-ahead from the semaphore, replace the signal
  56     if(0 == result) {
  57         dispatch_semaphore_signal(self.semaphore);
  58     }
  59
  60     return result;
  61 }
  62
  63 @end
  64