/core/externals/update-engine/externals/google-toolbox-for-mac/Foundation/GTMNSObject+KeyValueObserving.m
Objective C | 676 lines | 504 code | 77 blank | 95 comment | 36 complexity | 08992f313278a6ea9a3f390f26309bb4 MD5 | raw file
1// 2// GTMNSObject+KeyValueObserving.m 3// 4// Copyright 2009 Google Inc. 5// 6// Licensed under the Apache License, Version 2.0 (the "License"); you may not 7// use this file except in compliance with the License. You may obtain a copy 8// of the License at 9// 10// http://www.apache.org/licenses/LICENSE-2.0 11// 12// Unless required by applicable law or agreed to in writing, software 13// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 14// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 15// License for the specific language governing permissions and limitations under 16// the License. 17// 18 19// 20// MAKVONotificationCenter.m 21// MAKVONotificationCenter 22// 23// Created by Michael Ash on 10/15/08. 24// 25 26// This code is based on code by Michael Ash. 27// See comment in header. 28#import "GTMDefines.h" 29#import "GTMNSObject+KeyValueObserving.h" 30#import "GTMDefines.h" 31#import "GTMDebugSelectorValidation.h" 32#import "GTMObjC2Runtime.h" 33#import "GTMMethodCheck.h" 34 35// A singleton that works as a dispatch center for KVO 36// -[NSObject observeValueForKeyPath:ofObject:change:context:] and turns them 37// into selector dispatches. It stores a collection of 38// GTMKeyValueObservingHelpers, and keys them via the key generated by 39// -dictionaryKeyForObserver:ofObject:forKeyPath:selector. 40@interface GTMKeyValueObservingCenter : NSObject { 41 @private 42 NSMutableDictionary *observerHelpers_; 43} 44 45+ (id)defaultCenter; 46 47- (void)addObserver:(id)observer 48 ofObject:(id)target 49 forKeyPath:(NSString *)keyPath 50 selector:(SEL)selector 51 userInfo:(id)userInfo 52 options:(NSKeyValueObservingOptions)options; 53- (void)removeObserver:(id)observer 54 ofObject:(id)target 55 forKeyPath:(NSString *)keyPath 56 selector:(SEL)selector; 57- (id)dictionaryKeyForObserver:(id)observer 58 ofObject:(id)target 59 forKeyPath:(NSString *)keyPath 60 selector:(SEL)selector; 61@end 62 63@interface GTMKeyValueObservingHelper : NSObject { 64 @private 65 __weak id observer_; 66 SEL selector_; 67 id userInfo_; 68 __weak id target_; 69 NSString* keyPath_; 70} 71 72- (id)initWithObserver:(id)observer 73 object:(id)target 74 keyPath:(NSString *)keyPath 75 selector:(SEL)selector 76 userInfo:(id)userInfo 77 options:(NSKeyValueObservingOptions)options; 78- (void)deregister; 79 80@end 81 82@interface GTMKeyValueChangeNotification () 83- (id)initWithKeyPath:(NSString *)keyPath ofObject:(id)object 84 userInfo:(id)userInfo change:(NSDictionary *)change; 85@end 86 87@implementation GTMKeyValueObservingHelper 88 89// For info how and why we use these statics: 90// http://lists.apple.com/archives/cocoa-dev/2006/Jul/msg01038.html 91static char GTMKeyValueObservingHelperContextData; 92static char* GTMKeyValueObservingHelperContext 93 = >MKeyValueObservingHelperContextData; 94 95- (id)initWithObserver:(id)observer 96 object:(id)target 97 keyPath:(NSString *)keyPath 98 selector:(SEL)selector 99 userInfo:(id)userInfo 100 options:(NSKeyValueObservingOptions)options { 101 if((self = [super init])) { 102 observer_ = observer; 103 selector_ = selector; 104 userInfo_ = [userInfo retain]; 105 106 target_ = target; 107 keyPath_ = [keyPath retain]; 108 109 [target addObserver:self 110 forKeyPath:keyPath 111 options:options 112 context:GTMKeyValueObservingHelperContext]; 113 } 114 return self; 115} 116 117- (NSString *)description { 118 return [NSString stringWithFormat: 119 @"%@ <observer = %@ keypath = %@ target = %@ selector = %@>", 120 [self class], observer_, keyPath_, target_, 121 NSStringFromSelector(selector_)]; 122} 123 124- (void)dealloc { 125 if (target_) { 126 _GTMDevLog(@"Didn't deregister %@", self); 127 [self deregister]; 128 } 129 [userInfo_ release]; 130 [keyPath_ release]; 131 [super dealloc]; 132} 133 134- (void)observeValueForKeyPath:(NSString *)keyPath 135 ofObject:(id)object 136 change:(NSDictionary *)change 137 context:(void *)context { 138 if(context == GTMKeyValueObservingHelperContext) { 139 GTMKeyValueChangeNotification *notification 140 = [[GTMKeyValueChangeNotification alloc] initWithKeyPath:keyPath 141 ofObject:object 142 userInfo:userInfo_ 143 change:change]; 144 [observer_ performSelector:selector_ withObject:notification]; 145 [notification release]; 146 } else { 147 // COV_NF_START 148 // There's no way this should ever be called. 149 // If it is, the call will go up to NSObject which will assert. 150 [super observeValueForKeyPath:keyPath 151 ofObject:object 152 change:change 153 context:context]; 154 // COV_NF_END 155 } 156} 157 158- (void)deregister { 159 [target_ removeObserver:self forKeyPath:keyPath_]; 160 target_ = nil; 161} 162 163@end 164 165@implementation GTMKeyValueObservingCenter 166 167+ (id)defaultCenter { 168 static GTMKeyValueObservingCenter *center = nil; 169 if(!center) { 170 // do a bit of clever atomic setting to make this thread safe 171 // if two threads try to set simultaneously, one will fail 172 // and the other will set things up so that the failing thread 173 // gets the shared center 174 GTMKeyValueObservingCenter *newCenter = [[self alloc] init]; 175 if(!objc_atomicCompareAndSwapGlobalBarrier(nil, 176 newCenter, 177 (void *)¢er)) { 178 [newCenter release]; // COV_NF_LINE no guarantee we'll hit this line 179 } 180 } 181 return center; 182} 183 184- (id)init { 185 if((self = [super init])) { 186 observerHelpers_ = [[NSMutableDictionary alloc] init]; 187 } 188 return self; 189} 190 191// COV_NF_START 192// Singletons don't get deallocated 193- (void)dealloc { 194 [observerHelpers_ release]; 195 [super dealloc]; 196} 197// COV_NF_END 198 199- (id)dictionaryKeyForObserver:(id)observer 200 ofObject:(id)target 201 forKeyPath:(NSString *)keyPath 202 selector:(SEL)selector { 203 NSString *key = nil; 204 if (!target && !keyPath && !selector) { 205 key = [NSString stringWithFormat:@"%p:", observer]; 206 } else { 207 key = [NSString stringWithFormat:@"%p:%@:%p:%p", 208 observer, keyPath, selector, target]; 209 } 210 return key; 211} 212 213- (void)addObserver:(id)observer 214 ofObject:(id)target 215 forKeyPath:(NSString *)keyPath 216 selector:(SEL)selector 217 userInfo:(id)userInfo 218 options:(NSKeyValueObservingOptions)options { 219 GTMKeyValueObservingHelper *helper 220 = [[GTMKeyValueObservingHelper alloc] initWithObserver:observer 221 object:target 222 keyPath:keyPath 223 selector:selector 224 userInfo:userInfo 225 options:options]; 226 id key = [self dictionaryKeyForObserver:observer 227 ofObject:target 228 forKeyPath:keyPath 229 selector:selector]; 230 @synchronized(self) { 231 GTMKeyValueObservingHelper *oldHelper = [observerHelpers_ objectForKey:key]; 232 if (oldHelper) { 233 _GTMDevLog(@"%@ already observing %@ forKeyPath %@", 234 observer, target, keyPath); 235 [oldHelper deregister]; 236 } 237 [observerHelpers_ setObject:helper forKey:key]; 238 } 239 [helper release]; 240} 241 242- (void)removeObserver:(id)observer 243 ofObject:(id)target 244 forKeyPath:(NSString *)keyPath 245 selector:(SEL)selector { 246 id key = [self dictionaryKeyForObserver:observer 247 ofObject:target 248 forKeyPath:keyPath 249 selector:selector]; 250 NSMutableArray *allValidHelperKeys = [NSMutableArray array]; 251 NSArray *allValidHelpers = nil; 252 @synchronized(self) { 253 254 NSString *helperKey; 255 GTM_FOREACH_OBJECT(helperKey, [observerHelpers_ allKeys]) { 256 if ([helperKey hasPrefix:key]) { 257 [allValidHelperKeys addObject:helperKey]; 258 } 259 } 260#if DEBUG 261 if ([allValidHelperKeys count] == 0) { 262 _GTMDevLog(@"%@ was not observing %@ with keypath %@", 263 observer, target, keyPath); 264 } 265#endif // DEBUG 266 allValidHelpers = [observerHelpers_ objectsForKeys:allValidHelperKeys 267 notFoundMarker:[NSNull null]]; 268 [observerHelpers_ removeObjectsForKeys:allValidHelperKeys]; 269 } 270 [allValidHelpers makeObjectsPerformSelector:@selector(deregister)]; 271} 272 273@end 274 275@implementation NSObject (GTMKeyValueObservingAdditions) 276 277- (void)gtm_addObserver:(id)observer 278 forKeyPath:(NSString *)keyPath 279 selector:(SEL)selector 280 userInfo:(id)userInfo 281 options:(NSKeyValueObservingOptions)options { 282 _GTMDevAssert(observer && [keyPath length] && selector, 283 @"Missing observer, keyPath, or selector"); 284 GTMKeyValueObservingCenter *center 285 = [GTMKeyValueObservingCenter defaultCenter]; 286 GTMAssertSelectorNilOrImplementedWithArguments( 287 observer, 288 selector, 289 @encode(GTMKeyValueChangeNotification *), 290 NULL); 291 [center addObserver:observer 292 ofObject:self 293 forKeyPath:keyPath 294 selector:selector 295 userInfo:userInfo 296 options:options]; 297} 298 299- (void)gtm_removeObserver:(id)observer 300 forKeyPath:(NSString *)keyPath 301 selector:(SEL)selector { 302 _GTMDevAssert(observer && [keyPath length] && selector, 303 @"Missing observer, keyPath, or selector"); 304 GTMKeyValueObservingCenter *center 305 = [GTMKeyValueObservingCenter defaultCenter]; 306 GTMAssertSelectorNilOrImplementedWithArguments( 307 observer, 308 selector, 309 @encode(GTMKeyValueChangeNotification *), 310 NULL); 311 [center removeObserver:observer 312 ofObject:self 313 forKeyPath:keyPath 314 selector:selector]; 315} 316 317- (void)gtm_stopObservingAllKeyPaths { 318 GTMKeyValueObservingCenter *center 319 = [GTMKeyValueObservingCenter defaultCenter]; 320 [center removeObserver:self 321 ofObject:nil 322 forKeyPath:nil 323 selector:Nil]; 324} 325 326@end 327 328 329@implementation GTMKeyValueChangeNotification 330 331- (id)initWithKeyPath:(NSString *)keyPath ofObject:(id)object 332 userInfo:(id)userInfo change:(NSDictionary *)change { 333 if ((self = [super init])) { 334 keyPath_ = [keyPath copy]; 335 object_ = [object retain]; 336 userInfo_ = [userInfo retain]; 337 change_ = [change retain]; 338 } 339 return self; 340} 341 342- (void)dealloc { 343 [keyPath_ release]; 344 [object_ release]; 345 [userInfo_ release]; 346 [change_ release]; 347 [super dealloc]; 348} 349 350- (id)copyWithZone:(NSZone *)zone { 351 return [[[self class] allocWithZone:zone] initWithKeyPath:keyPath_ 352 ofObject:object_ 353 userInfo:userInfo_ 354 change:change_]; 355} 356 357- (BOOL)isEqual:(id)object { 358 return ([keyPath_ isEqualToString:[object keyPath]] 359 && [object_ isEqual:[object object]] 360 && [userInfo_ isEqual:[object userInfo]] 361 && [change_ isEqual:[object change]]); 362} 363 364- (NSString *)description { 365 return [NSString stringWithFormat: 366 @"%@ <object = %@ keypath = %@ userInfo = %@ change = %@>", 367 [self class], object_, keyPath_, userInfo_, change_]; 368} 369 370- (NSUInteger)hash { 371 return [keyPath_ hash] + [object_ hash] + [userInfo_ hash] + [change_ hash]; 372} 373 374- (NSString *)keyPath { 375 return keyPath_; 376} 377 378- (id)object { 379 return object_; 380} 381 382- (id)userInfo { 383 return userInfo_; 384} 385 386- (NSDictionary *)change { 387 return change_; 388} 389 390@end 391 392#ifdef DEBUG 393 394static void SwizzleMethodsInClass(Class cls, SEL sel1, SEL sel2) { 395 Method m1 = class_getInstanceMethod(cls, sel1); 396 Method m2 = class_getInstanceMethod(cls, sel2); 397 method_exchangeImplementations(m1, m2); 398} 399 400#if GTM_PERFORM_KVO_CHECKS 401 402// This is only used when GTM_PERFORM_KVO_CHECKS is on. 403static void SwizzleClassMethodsInClass(Class cls, SEL sel1, SEL sel2) { 404 Method m1 = class_getClassMethod(cls, sel1); 405 Method m2 = class_getClassMethod(cls, sel2); 406 method_exchangeImplementations(m1, m2); 407} 408 409#endif // GTM_PERFORM_KVO_CHECKS 410 411// This category exists to attempt to help deal with tricky KVO issues. 412// KVO is a wonderful technology in some ways, but is extremely fragile and 413// allows developers a lot of freedom to shoot themselves in the foot. 414// Refactoring an app that uses a lot of KVO can be really difficult, as can 415// debugging it. 416// These are some tools that we have found useful when working with KVO. Note 417// that these tools are only on in Debug builds. 418// 419// We have divided these tools up into two categories: Checks and Debugs. 420// 421// Debugs 422// Debugs are mainly for logging all the KVO/KVC that is occurring in your 423// application. To enable our KVO debugging, set the GTMDebugKVO environment 424// variable to 1 and you will get a whole pile of KVO logging that may help you 425// track down problems. 426// bash - export GTMDebugKVO=1 427// csh/tcsh - setenv GTMDebugKVO 1 428// 429// Checks 430// First we believe that instance variables should be private by default, 431// and that any KVO should be done via accessors. Apple by default allows KVO 432// to get at instance variables directly. Since our coding standards define 433// that instance variables should be @private, we feel that KVO shouldn't be 434// breaking this encapsulation. Unfortunately the @private, @protected 435// designators are a compile time convention only, and don't get carried over 436// into the runtime, so there's no way to check on an individual iVar what 437// it's visibility is. We therefore assume that an instance variable is private, 438// and disallow KVO access to instance variables. The problem with most KVO 439// issues is that they occur at runtime and unless you execute that case you 440// may never see the bug until it's too late. We try to force KVO issues to 441// rear their head at the time of the observing if at all possible. 442// Checks are on by default in debug builds. They can be turned off by defining 443// the compile flag GTM_PERFORM_KVO_CHECKS to 0 444// i.e. #define GTM_PERFORM_KVO_CHECKS 0, or set it 445// in GCC_PREPROCESSOR_DEFINITIONS. 446// 447// Checks work at a couple of different levels. 448// The most restrictive of the checks is that we set 449// |accessInstanceVariablesDirectly| to NO by default. This means that if you 450// attempt to perform KVO on an instance variable, you will get an exception 451// thrown. 452// Also, when adding an observer, we check to see if any member of the path 453// starts or ends with _ which by convention denotes an instance variable. If so 454// we warn you about attempting to access a ivar directly. 455 456@interface NSObject (GTMDebugKeyValueObserving) 457- (void)_gtmDebugAddObserver:(NSObject *)observer 458 forKeyPath:(NSString *)keyPath 459 options:(NSKeyValueObservingOptions)options 460 context:(void *)context; 461- (void)_gtmDebugArrayAddObserver:(NSObject *)observer 462 toObjectsAtIndexes:(NSIndexSet *)indexes 463 forKeyPath:(NSString *)keyPath 464 options:(NSKeyValueObservingOptions)options 465 context:(void *)context; 466- (void)_gtmDebugRemoveObserver:(NSObject *)observer 467 forKeyPath:(NSString *)keyPath; 468- (void)_gtmDebugArrayRemoveObserver:(NSObject *)observer 469 fromObjectsAtIndexes:(NSIndexSet *)indexes 470 forKeyPath:(NSString *)keyPath; 471- (void)_gtmDebugWillChangeValueForKey:(NSString*)key; 472- (void)_gtmDebugDidChangeValueForKey:(NSString*)key; 473 474#if GTM_PERFORM_KVO_CHECKS 475 476- (void)_gtmCheckAddObserver:(NSObject *)observer 477 forKeyPath:(NSString *)keyPath 478 options:(NSKeyValueObservingOptions)options 479 context:(void *)context; 480- (void)_gtmCheckAddObserver:(NSObject *)observer 481 toObjectsAtIndexes:(NSIndexSet *)indexes 482 forKeyPath:(NSString *)keyPath 483 options:(NSKeyValueObservingOptions)options 484 context:(void *)context; 485+ (BOOL)_gtmAccessInstanceVariablesDirectly; 486 487#endif // GTM_PERFORM_KVO_CHECKS 488@end 489 490@implementation NSObject (GTMDebugKeyValueObserving) 491GTM_METHOD_CHECK(NSObject, _gtmDebugAddObserver:forKeyPath:options:context:); 492GTM_METHOD_CHECK(NSObject, _gtmDebugRemoveObserver:forKeyPath:); 493GTM_METHOD_CHECK(NSObject, _gtmDebugWillChangeValueForKey:); 494GTM_METHOD_CHECK(NSObject, _gtmDebugDidChangeValueForKey:); 495GTM_METHOD_CHECK(NSArray, 496 _gtmDebugArrayAddObserver:toObjectsAtIndexes:forKeyPath:options:context:); 497GTM_METHOD_CHECK(NSArray, 498 _gtmDebugArrayRemoveObserver:fromObjectsAtIndexes:forKeyPath:); 499 500#if GTM_PERFORM_KVO_CHECKS 501 502GTM_METHOD_CHECK(NSObject, 503 _gtmCheckAddObserver:forKeyPath:options:context:); 504GTM_METHOD_CHECK(NSArray, 505 _gtmCheckAddObserver:toObjectsAtIndexes:forKeyPath:options:context:); 506GTM_METHOD_CHECK(NSObject, 507 _gtmAccessInstanceVariablesDirectly); 508 509#endif // GTM_PERFORM_KVO_CHECKS 510 511+ (void)load { 512 NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; 513 NSDictionary *env = [[NSProcessInfo processInfo] environment]; 514 id debugKeyValue = [env valueForKey:@"GTMDebugKVO"]; 515 BOOL debug = NO; 516 if ([debugKeyValue isKindOfClass:[NSNumber class]]) { 517 debug = [debugKeyValue intValue] != 0 ? YES : NO; 518 } else if ([debugKeyValue isKindOfClass:[NSString class]]) { 519 debug = ([debugKeyValue hasPrefix:@"Y"] || [debugKeyValue hasPrefix:@"T"] || 520 [debugKeyValue intValue]); 521 } 522 Class cls = Nil; 523 if (debug) { 524 cls = [NSObject class]; 525 SwizzleMethodsInClass(cls, 526 @selector(addObserver:forKeyPath:options:context:), 527 @selector(_gtmDebugAddObserver:forKeyPath:options:context:)); 528 SwizzleMethodsInClass(cls, 529 @selector(removeObserver:forKeyPath:), 530 @selector(_gtmDebugRemoveObserver:forKeyPath:)); 531 SwizzleMethodsInClass(cls, 532 @selector(willChangeValueForKey:), 533 @selector(_gtmDebugWillChangeValueForKey:)); 534 SwizzleMethodsInClass(cls, 535 @selector(didChangeValueForKey:), 536 @selector(_gtmDebugDidChangeValueForKey:)); 537 cls = [NSArray class]; 538 SwizzleMethodsInClass(cls, 539 @selector(addObserver:toObjectsAtIndexes:forKeyPath:options:context:), 540 @selector(_gtmDebugArrayAddObserver:toObjectsAtIndexes:forKeyPath:options:context:)); 541 SwizzleMethodsInClass(cls, 542 @selector(removeObserver:fromObjectsAtIndexes:forKeyPath:), 543 @selector(_gtmDebugArrayRemoveObserver:fromObjectsAtIndexes:forKeyPath:)); 544 } 545#if GTM_PERFORM_KVO_CHECKS 546 cls = [NSObject class]; 547 SwizzleMethodsInClass(cls, 548 @selector(addObserver:forKeyPath:options:context:), 549 @selector(_gtmCheckAddObserver:forKeyPath:options:context:)); 550 SwizzleClassMethodsInClass(cls, 551 @selector(accessInstanceVariablesDirectly), 552 @selector(_gtmAccessInstanceVariablesDirectly)); 553 cls = [NSArray class]; 554 SwizzleMethodsInClass(cls, 555 @selector(addObserver:toObjectsAtIndexes:forKeyPath:options:context:), 556 @selector(_gtmCheckAddObserver:toObjectsAtIndexes:forKeyPath:options:context:)); 557 558#endif // GTM_PERFORM_KVO_CHECKS 559 [pool drain]; 560} 561 562- (void)_gtmDebugAddObserver:(NSObject *)observer 563 forKeyPath:(NSString *)keyPath 564 options:(NSKeyValueObservingOptions)options 565 context:(void *)context { 566 _GTMDevLog(@"Adding observer %@ to %@ keypath '%@'", observer, self, keyPath); 567 [self _gtmDebugAddObserver:observer forKeyPath:keyPath 568 options:options context:context]; 569} 570 571- (void)_gtmDebugArrayAddObserver:(NSObject *)observer 572 toObjectsAtIndexes:(NSIndexSet *)indexes 573 forKeyPath:(NSString *)keyPath 574 options:(NSKeyValueObservingOptions)options 575 context:(void *)context { 576 _GTMDevLog(@"Array adding observer %@ to indexes %@ of %@ keypath '%@'", 577 observer, indexes, self, keyPath); 578 [self _gtmDebugArrayAddObserver:observer 579 toObjectsAtIndexes:indexes 580 forKeyPath:keyPath 581 options:options context:context]; 582} 583 584- (void)_gtmDebugRemoveObserver:(NSObject *)observer 585 forKeyPath:(NSString *)keyPath { 586 _GTMDevLog(@"Removing observer %@ from %@ keypath '%@'", 587 observer, self, keyPath); 588 [self _gtmDebugRemoveObserver:observer forKeyPath:keyPath]; 589} 590 591- (void)_gtmDebugArrayRemoveObserver:(NSObject *)observer 592 fromObjectsAtIndexes:(NSIndexSet *)indexes 593 forKeyPath:(NSString *)keyPath { 594 _GTMDevLog(@"Array removing observer %@ from indexes %@ of %@ keypath '%@'", 595 indexes, observer, self, keyPath); 596 [self _gtmDebugArrayRemoveObserver:observer 597 fromObjectsAtIndexes:indexes 598 forKeyPath:keyPath]; 599} 600 601- (void)_gtmDebugWillChangeValueForKey:(NSString*)key { 602 _GTMDevLog(@"Will change '%@' of %@", key, self); 603 [self _gtmDebugWillChangeValueForKey:key]; 604} 605 606- (void)_gtmDebugDidChangeValueForKey:(NSString*)key { 607 _GTMDevLog(@"Did change '%@' of %@", key, self); 608 [self _gtmDebugDidChangeValueForKey:key]; 609} 610 611#if GTM_PERFORM_KVO_CHECKS 612 613- (void)_gtmCheckAddObserver:(NSObject *)observer 614 forKeyPath:(NSString *)keyPath 615 options:(NSKeyValueObservingOptions)options 616 context:(void *)context { 617 NSArray *keyPathElements = [keyPath componentsSeparatedByString:@"."]; 618 NSString *element; 619 GTM_FOREACH_OBJECT(element, keyPathElements) { 620 if ([element hasPrefix:@"_"] || [element hasSuffix:@"_"]) { 621 _GTMDevLog(@"warning: %@ is registering an observation on what appears " 622 @"to be a private ivar of %@ (or a sub keyed object) with " 623 @"element %@ of keyPath %@.", observer, self, element, 624 keyPath); 625 } 626 } 627 [self _gtmCheckAddObserver:observer 628 forKeyPath:keyPath 629 options:options 630 context:context]; 631} 632 633- (void)_gtmCheckAddObserver:(NSObject *)observer 634 toObjectsAtIndexes:(NSIndexSet *)indexes 635 forKeyPath:(NSString *)keyPath 636 options:(NSKeyValueObservingOptions)options 637 context:(void *)context { 638 NSArray *keyPathElements = [keyPath componentsSeparatedByString:@"."]; 639 NSString *element; 640 GTM_FOREACH_OBJECT(element, keyPathElements) { 641 if ([element hasPrefix:@"_"] || [element hasSuffix:@"_"]) { 642 _GTMDevLog(@"warning: %@ is registering an observation on what appears " 643 @"to be a private ivar of %@ (or a sub keyed object) with " 644 @"element %@ of keyPath %@.", observer, self, element, 645 keyPath); 646 } 647 } 648 [self _gtmCheckAddObserver:observer 649 toObjectsAtIndexes:indexes 650 forKeyPath:keyPath 651 options:options 652 context:context]; 653} 654 655 656+ (BOOL)_gtmAccessInstanceVariablesDirectly { 657 // Apple has lots of "bad" direct instance variable accesses, so we 658 // only want to check our code, as opposed to library code. iOS simulator 659 // builds copy the app into the user's home directory. Xcode 4 also changes 660 // the default location of the output directory. Don't count being within 661 // the user's home and under "/Library/" as being a system library. 662 663 // If this turns out to be slow, we may want to consider a cache to speed 664 // things up. 665 NSBundle *bundle = [NSBundle bundleForClass:self]; 666 NSString *path = [bundle bundlePath]; 667 BOOL hasLibrary = [path rangeOfString:@"/Library/"].location != NSNotFound; 668 BOOL startsWithUser = [path hasPrefix:@"/Users/"]; 669 return !startsWithUser && hasLibrary; 670} 671 672#endif // GTM_PERFORM_KVO_CHECKS 673 674@end 675 676#endif // DEBUG