keychain/ckks/CKKSResultOperation.m

   1 /*
   2  * Copyright (c) 2016 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 #if OCTAGON
  25
  26 #import "keychain/ckks/CKKSResultOperation.h"
  27 #import "keychain/ckks/NSOperationCategories.h"
  28 #import "keychain/ckks/CKKSCondition.h"
  29 #import "keychain/categories/NSError+UsefulConstructors.h"
  30 #include <utilities/debugging.h>
  31
  32 @interface CKKSResultOperation()
  33 @property NSMutableArray<CKKSResultOperation*>* successDependencies;
  34 @property bool timeoutCanOccur;
  35 @property dispatch_queue_t timeoutQueue;
  36 @property void (^finishingBlock)(void);
  37 @end
  38
  39 @implementation CKKSResultOperation
  40 - (instancetype)init {
  41     if(self = [super init]) {
  42         _error = nil;
  43         _successDependencies = [[NSMutableArray alloc] init];
  44         _timeoutCanOccur = true;
  45         _timeoutQueue = dispatch_queue_create("result-operation-timeout", DISPATCH_QUEUE_SERIAL);
  46         _completionHandlerDidRunCondition = [[CKKSCondition alloc] init];
  47
  48         __weak __typeof(self) weakSelf = self;
  49         _finishingBlock = ^(void) {
  50             weakSelf.finishDate = [NSDate dateWithTimeIntervalSinceNow:0];
  51         };
  52         self.completionBlock = ^{}; // our _finishing block gets added in the method override
  53     }
  54     return self;
  55 }
  56
  57 - (NSString*)operationStateString {
  58     return ([self isFinished] ? [NSString stringWithFormat:@"finished %@", self.finishDate] :
  59             [self isCancelled] ? @"cancelled" :
  60             [self isExecuting] ? @"executing" :
  61             [self isReady] ? @"ready" :
  62             @"pending");
  63 }
  64
  65 - (NSString*)description {
  66     NSString* state = [self operationStateString];
  67
  68     if(self.error) {
  69         return [NSString stringWithFormat: @"<%@: %@ error:%@>", [self selfname], state, self.error];
  70     } else {
  71         return [NSString stringWithFormat: @"<%@: %@%@>", [self selfname], state, [self pendingDependenciesString:@" dep:"]];
  72     }
  73 }
  74
  75 - (NSString*)debugDescription {
  76     return [self description];
  77 }
  78
  79 - (void)setCompletionBlock:(void (^)(void))completionBlock
  80 {
  81     __weak __typeof(self) weakSelf = self;
  82     [super setCompletionBlock:^(void) {
  83         __strong __typeof(self) strongSelf = weakSelf;
  84         if (!strongSelf) {
  85             secerror("ckksresultoperation: completion handler called on deallocated operation instance");
  86             completionBlock(); // go ahead and still behave as things would if this method override were not here
  87             return;
  88         }
  89
  90         strongSelf.finishingBlock();
  91         completionBlock();
  92         [strongSelf.completionHandlerDidRunCondition fulfill];
  93
  94         for (NSOperation *op in strongSelf.dependencies) {
  95             [strongSelf removeDependency:op];
  96         }
  97     }];
  98 }
  99
 100 - (void)start {
 101     if(![self allDependentsSuccessful]) {
 102         secdebug("ckksresultoperation", "Not running due to some failed dependent: %@", self.error);
 103         [self cancel];
 104     } else {
 105         [self invalidateTimeout];
 106
 107     }
 108
 109     [super start];
 110 }
 111
 112 - (void)invalidateTimeout {
 113     dispatch_sync(self.timeoutQueue, ^{
 114         if(![self isCancelled]) {
 115             self.timeoutCanOccur = false;
 116         };
 117     });
 118 }
 119
 120 - (NSError* _Nullable)dependenciesDescriptionError {
 121     NSError* underlyingReason = nil;
 122     NSArray* dependencies = [self.dependencies copy];
 123     dependencies = [dependencies objectsAtIndexes: [dependencies indexesOfObjectsPassingTest: ^BOOL (id obj,
 124                                                                                                      NSUInteger idx,
 125                                                                                                      BOOL* stop) {
 126         return [obj isFinished] ? NO : YES;
 127     }]];
 128
 129     for(NSOperation* dependency in dependencies) {
 130         if([dependency isKindOfClass:[CKKSResultOperation class]]) {
 131             CKKSResultOperation* ro = (CKKSResultOperation*)dependency;
 132             underlyingReason = [ro descriptionError] ?: underlyingReason;
 133         }
 134     }
 135
 136     return underlyingReason;
 137 }
 138
 139 // Returns, for this CKKSResultOperation, an error describing this operation or its dependents.
 140 // Used mainly by other CKKSResultOperations who time out waiting for this operation to start/complete.
 141 - (NSError* _Nullable)descriptionError {
 142     if(self.descriptionErrorCode != 0) {
 143         return [NSError errorWithDomain:CKKSResultDescriptionErrorDomain
 144                                    code:self.descriptionErrorCode
 145                                userInfo:nil];
 146     } else {
 147         return [self dependenciesDescriptionError];
 148     }
 149 }
 150
 151 - (NSError*)_onqueueTimeoutError {
 152     // Find if any of our dependencies are CKKSResultOperations with a custom reason for existing
 153
 154     NSError* underlyingReason = [self descriptionError];
 155
 156     NSError* error = [NSError errorWithDomain:CKKSResultErrorDomain
 157                                          code:CKKSResultTimedOut
 158                                   description:[NSString stringWithFormat:@"Operation(%@) timed out waiting to start for [%@]",
 159                                                [self selfname],
 160                                                [self pendingDependenciesString:@""]]
 161                                    underlying:underlyingReason];
 162     return error;
 163 }
 164
 165 - (instancetype)timeout:(dispatch_time_t)timeout {
 166     __weak __typeof(self) weakSelf = self;
 167     dispatch_after(dispatch_time(DISPATCH_TIME_NOW, timeout), self.timeoutQueue, ^{
 168         __strong __typeof(self) strongSelf = weakSelf;
 169         if(strongSelf.timeoutCanOccur) {
 170             strongSelf.error = [self _onqueueTimeoutError];
 171             strongSelf.timeoutCanOccur = false;
 172             [strongSelf cancel];
 173         }
 174     });
 175
 176     return self;
 177 }
 178
 179 - (void)addSuccessDependency:(CKKSResultOperation *)operation {
 180     [self addNullableSuccessDependency:operation];
 181 }
 182
 183 - (void)addNullableSuccessDependency:(CKKSResultOperation *)operation {
 184     if(!operation) {
 185         return;
 186     }
 187     @synchronized(self) {
 188         [self.successDependencies addObject: operation];
 189         [self addDependency: operation];
 190     }
 191 }
 192
 193 - (bool)allDependentsSuccessful {
 194     return [self allSuccessful: self.successDependencies];
 195 }
 196
 197 - (bool)allSuccessful: (NSArray<CKKSResultOperation*>*) operations {
 198     @synchronized(self) {
 199         bool result = false;
 200
 201         bool finished = true;   // all dependents must be finished
 202         bool cancelled = false; // no dependents can be cancelled
 203         bool failed = false;    // no dependents can have failed
 204         NSMutableArray<NSOperation*>* cancelledSuboperations = [NSMutableArray array];
 205
 206         for(CKKSResultOperation* op in operations) {
 207             finished  &= !!([op isFinished]);
 208             cancelled |= !!([op isCancelled]);
 209             failed    |= (op.error != nil);
 210
 211             if([op isCancelled]) {
 212                 [cancelledSuboperations addObject:op];
 213             }
 214
 215             // TODO: combine suberrors
 216             if(op.error != nil) {
 217                 if([op.error.domain isEqual: CKKSResultErrorDomain] && op.error.code == CKKSResultSubresultError) {
 218                     // Already a subresult, just copy it on in
 219                     self.error = op.error;
 220                 } else {
 221                     self.error = [NSError errorWithDomain:CKKSResultErrorDomain
 222                                                      code:CKKSResultSubresultError
 223                                               description:@"Success-dependent operation failed"
 224                                                underlying:op.error];
 225                 }
 226             }
 227         }
 228
 229         result = finished && !( cancelled || failed );
 230
 231         if(!result && self.error == nil) {
 232             self.error = [NSError errorWithDomain:CKKSResultErrorDomain code: CKKSResultSubresultCancelled userInfo:@{NSLocalizedDescriptionKey:[NSString stringWithFormat:@"Operation (%@) cancelled", cancelledSuboperations]}];
 233         }
 234         return result;
 235     }
 236 }
 237
 238 + (CKKSResultOperation*)operationWithBlock:(void (^)(void))block {
 239     CKKSResultOperation* op = [[CKKSResultOperation alloc] init];
 240     [op addExecutionBlock: block];
 241     return op;
 242 }
 243
 244 +(instancetype)named:(NSString*)name withBlock:(void(^)(void)) block {
 245     CKKSResultOperation* blockOp = [CKKSResultOperation operationWithBlock: block];
 246     blockOp.name = name;
 247     return blockOp;
 248 }
 249
 250 + (instancetype)named:(NSString*)name withBlockTakingSelf:(void(^)(CKKSResultOperation* op))block
 251 {
 252     CKKSResultOperation* op = [[CKKSResultOperation alloc] init];
 253     __weak __typeof(op) weakOp = op;
 254     [op addExecutionBlock:^{
 255         __strong __typeof(op) strongOp = weakOp;
 256         block(strongOp);
 257     }];
 258     op.name = name;
 259     return op;
 260 }
 261 @end
 262
 263 #endif // OCTAGON