Added logic to identify expected values to avoid race

Fixed review comments about spelling
Removed MTRPair class

src/darwin/Framework/CHIP/MTRDevice.mm

@@ -48,27 +48,7 @@
 
 // Consider moving utility classes to their own file
 #pragma mark - Utility Classes
-@interface MTRPair<FirstObjectType, SecondObjectType> : NSObject
-+ (instancetype)pairWithFirst:(FirstObjectType)first second:(SecondObjectType)second;
-@property (nonatomic, readonly) FirstObjectType first;
-@property (nonatomic, readonly) SecondObjectType second;
-@end
-
-@implementation MTRPair
-- (instancetype)initWithFirst:(id)first second:(id)second
-{
- if (self = [super init]) {
- _first = first;
- _second = second;
- }
- return self;
-}
-+ (instancetype)pairWithFirst:(id)first second:(id)second
-{
- return [[self alloc] initWithFirst:first second:second];
-}
-@end
-
+// This class is for storing weak references in a container
 @interface MTRWeakReference<ObjectType> : NSObject
 + (instancetype)weakReferenceWithObject:(ObjectType)object;
 - (instancetype)initWithObject:(ObjectType)object;
@@ -171,6 +151,12 @@ MTREventPriority MTREventPriorityForValidPriorityLevel(chip::app::PriorityLevel
 } // anonymous namespace
 
 #pragma mark - MTRDevice
+typedef NS_ENUM(NSUInteger, MTRDeviceExpectedValueFieldIndex) {
+ MTRDeviceExpectedValueFieldExpirationTimeIndex = 0,
+ MTRDeviceExpectedValueFieldValueIndex = 1,
+ MTRDeviceExpectedValueFieldIDIndex = 2
+};
+
 @interface MTRDevice ()
 @property (nonatomic, readonly) os_unfair_lock lock; // protects the caches and device state
 @property (nonatomic) chip::FabricIndex fabricIndex;
@@ -200,9 +186,11 @@ @interface MTRDevice ()
 // See MTRDeviceResponseHandler definition for value dictionary details.
 @property (nonatomic) NSMutableDictionary<MTRAttributePath *, NSDictionary *> * readCache;
 
-// Expected value cache is attributePath => MTRPair of [NSDate of expiration time, NSDictionary of value]
+// Expected value cache is attributePath => NSArray of [NSDate of expiration time, NSDictionary of value, expected value ID]
+// - MTRDeviceExpectedValueFieldIndex
 // See MTRDeviceResponseHandler definition for value dictionary details.
-@property (nonatomic) NSMutableDictionary<MTRAttributePath *, MTRPair<NSDate *, NSDictionary *> *> * expectedValueCache;
+@property (nonatomic) NSMutableDictionary<MTRAttributePath *, NSArray *> * expectedValueCache;
+@property (nonatomic) uint64_t expectedValueNextID;
 
 @property (nonatomic) BOOL expirationCheckScheduled;
 
@@ -719,6 +707,13 @@ - (void)writeAttributeWithEndpointID:(NSNumber *)endpointID
  MTRAttributePath * attributePath = [MTRAttributePath attributePathWithEndpointID:endpointID
  clusterID:clusterID
  attributeID:attributeID];
+ // Commit change into expected value cache
+ NSDictionary * newExpectedValueDictionary = @{ MTRAttributePathKey : attributePath, MTRDataKey : value };
+ uint64_t expectedValueID;
+ [self setExpectedValues:@[ newExpectedValueDictionary ]
+ expectedValueInterval:expectedValueInterval
+ expectedValueID:&expectedValueID];
+
  MTRAsyncCallbackQueueWorkItem * workItem = [[MTRAsyncCallbackQueueWorkItem alloc] initWithQueue:self.queue];
  MTRAsyncCallbackReadyHandler readyHandler = ^(MTRDevice * device, NSUInteger retryCount) {
  MTR_LOG_INFO("%@ dequeueWorkItem %@", logPrefix, self->_asyncCallbackWorkQueue);
@@ -734,18 +729,13 @@ - (void)writeAttributeWithEndpointID:(NSNumber *)endpointID
  MTR_LOG_INFO("%@ completion error %@ endWork", logPrefix, error);
  [workItem endWork];
  if (error) {
- [self removeExpectedValuesForAttributePath:attributePath];
+ [self removeExpectedValueForAttributePath:attributePath expectedValueID:expectedValueID];
  }
  }];
  };
  workItem.readyHandler = readyHandler;
  MTR_LOG_INFO("%@ enqueueWorkItem %@", logPrefix, _asyncCallbackWorkQueue);
  [_asyncCallbackWorkQueue enqueueWorkItem:workItem];
-
- // Commit change into expected value cache
- NSDictionary * newExpectedValueDictionary = @{ MTRAttributePathKey : attributePath, MTRDataKey : value };
-
- [self setExpectedValues:@[ newExpectedValueDictionary ] expectedValueInterval:expectedValueInterval];
 }
 
 - (void)invokeCommandWithEndpointID:(NSNumber *)endpointID
@@ -767,6 +757,16 @@ - (void)invokeCommandWithEndpointID:(NSNumber *)endpointID
  } else {
  expectedValueInterval = MTRClampedNumber(expectedValueInterval, @(1), @(UINT32_MAX));
  }
+
+ uint64_t expectedValueID = 0;
+ NSMutableArray<MTRAttributePath *> * attributePaths = nil;
+ if (expectedValues) {
+ [self setExpectedValues:expectedValues expectedValueInterval:expectedValueInterval expectedValueID:&expectedValueID];
+ attributePaths = [NSMutableArray array];
+ for (NSDictionary<NSString *, id> * expectedValue in expectedValues) {
+ [attributePaths addObject:expectedValue[MTRAttributePathKey]];
+ }
+ }
  MTRAsyncCallbackQueueWorkItem * workItem = [[MTRAsyncCallbackQueueWorkItem alloc] initWithQueue:self.queue];
  MTRAsyncCallbackReadyHandler readyHandler = ^(MTRDevice * device, NSUInteger retryCount) {
  MTR_LOG_INFO("%@ dequeueWorkItem %@", logPrefix, self->_asyncCallbackWorkQueue);
@@ -784,15 +784,14 @@ - (void)invokeCommandWithEndpointID:(NSNumber *)endpointID
  completion(values, error);
  });
  [workItem endWork];
+ if (error && expectedValues) {
+ [self removeExpectedValuesForAttributePaths:attributePaths expectedValueID:expectedValueID];
+ }
  }];
  };
  workItem.readyHandler = readyHandler;
  MTR_LOG_INFO("%@ enqueueWorkItem %@", logPrefix, _asyncCallbackWorkQueue);
  [_asyncCallbackWorkQueue enqueueWorkItem:workItem];
-
- if (expectedValues) {
- [self setExpectedValues:expectedValues expectedValueInterval:expectedValueInterval];
- }
 }
 
 - (void)openCommissioningWindowWithSetupPasscode:(NSNumber *)setupPasscode
@@ -828,14 +827,15 @@ - (void)_checkExpiredExpectedValues
  // find expired attributes, and calculate next timer fire date
  NSDate * now = [NSDate date];
  NSDate * nextExpirationDate = nil;
- NSMutableSet<MTRPair<MTRAttributePath *, NSDictionary *> *> * attributeInfoToRemove = [NSMutableSet set];
+ // Set of NSArray with 2 elements [path, value] - this is used in this method only
+ NSMutableSet<NSArray *> * attributeInfoToRemove = [NSMutableSet set];
  for (MTRAttributePath * attributePath in _expectedValueCache) {
- MTRPair<NSDate *, NSDictionary *> * expectedValue = _expectedValueCache[attributePath];
- NSDate * attributeExpirationDate = expectedValue.first;
+ NSArray * expectedValue = _expectedValueCache[attributePath];
+ NSDate * attributeExpirationDate = expectedValue[MTRDeviceExpectedValueFieldExpirationTimeIndex];
  if (expectedValue) {
  if ([now compare:attributeExpirationDate] == NSOrderedDescending) {
  // expired - save [path, values] pair to attributeToRemove
- [attributeInfoToRemove addObject:[MTRPair pairWithFirst:attributePath second:expectedValue.second]];
+ [attributeInfoToRemove addObject:@[ attributePath, expectedValue[MTRDeviceExpectedValueFieldValueIndex] ]];
  } else {
  // get the next expiration date
  if (!nextExpirationDate || [nextExpirationDate compare:attributeExpirationDate] == NSOrderedDescending) {
@@ -848,10 +848,10 @@ - (void)_checkExpiredExpectedValues
  // remove from expected value cache and report attributes as needed
  NSMutableArray * attributesToReport = [NSMutableArray array];
  NSMutableArray * attributePathsToReport = [NSMutableArray array];
- for (MTRPair<MTRAttributePath *, NSDictionary *> * attributeInfo in attributeInfoToRemove) {
+ for (NSArray * attributeInfo in attributeInfoToRemove) {
  // compare with known value and mark for report if different
- MTRAttributePath * attributePath = attributeInfo.first;
- NSDictionary * attributeDataValue = attributeInfo.second;
+ MTRAttributePath * attributePath = attributeInfo[0];
+ NSDictionary * attributeDataValue = attributeInfo[1];
  NSDictionary * cachedAttributeDataValue = _readCache[attributePath];
  if (cachedAttributeDataValue
  && ![self _attributeDataValue:attributeDataValue isEqualToDataValue:cachedAttributeDataValue]) {
@@ -898,17 +898,17 @@ - (void)_performScheduledExpirationCheck
  os_unfair_lock_lock(&self->_lock);
 
  // First check expected value cache
- MTRPair<NSDate *, NSDictionary *> * expectedValue = _expectedValueCache[attributePath];
+ NSArray * expectedValue = _expectedValueCache[attributePath];
  if (expectedValue) {
  NSDate * now = [NSDate date];
- if ([now compare:expectedValue.first] == NSOrderedDescending) {
+ if ([now compare:expectedValue[MTRDeviceExpectedValueFieldExpirationTimeIndex]] == NSOrderedDescending) {
  // expired - purge and fall through
  _expectedValueCache[attributePath] = nil;
  } else {
  os_unfair_lock_unlock(&self->_lock);
 
  // not yet expired - return result
- return expectedValue.second;
+ return expectedValue[MTRDeviceExpectedValueFieldValueIndex];
  }
  }
 
@@ -965,9 +965,10 @@ - (NSArray *)_getAttributesToReportWithReportedValues:(NSArray<NSDictionary<NSSt
  _readCache[attributePath] = nil;
  } else {
  // if expected values exists, purge and update read cache
- MTRPair<NSDate *, NSDictionary *> * expectedValue = _expectedValueCache[attributePath];
+ NSArray * expectedValue = _expectedValueCache[attributePath];
  if (expectedValue) {
- if (![self _attributeDataValue:attributeDataValue isEqualToDataValue:expectedValue.second]) {
+ if (![self _attributeDataValue:attributeDataValue
+ isEqualToDataValue:expectedValue[MTRDeviceExpectedValueFieldValueIndex]]) {
  shouldReportAttribute = YES;
  }
  _expectedValueCache[attributePath] = nil;
@@ -998,23 +999,30 @@ - (NSArray *)_getAttributesToReportWithReportedValues:(NSArray<NSDictionary<NSSt
  return attributesToReport;
 }
 
+// If value is non-nil, return new expected value ID in the expectedValueID.
+// If value is nil, use the expectedValueID pointed
 - (void)_setExpectedValue:(NSDictionary<NSString *, id> *)expectedAttributeValue
  attributePath:(MTRAttributePath *)attributePath
  expirationTime:(NSDate *)expirationTime
  shouldReportValue:(BOOL *)shouldReportValue
  attributeValueToReport:(NSDictionary<NSString *, id> **)attributeValueToReport
+ expectedValueID:(uint64_t *)expectedValueID
 {
+ os_unfair_lock_assert_owner(&self->_lock);
+
  *shouldReportValue = NO;
 
- MTRPair<NSDate *, NSDictionary *> * previousExpectedValue = _expectedValueCache[attributePath];
+ NSArray * previousExpectedValue = _expectedValueCache[attributePath];
  if (previousExpectedValue) {
  if (expectedAttributeValue
- && ![self _attributeDataValue:expectedAttributeValue isEqualToDataValue:previousExpectedValue.second]) {
+ && ![self _attributeDataValue:expectedAttributeValue
+ isEqualToDataValue:previousExpectedValue[MTRDeviceExpectedValueFieldValueIndex]]) {
  // Case where new expected value overrides previous expected value - report new expected value
  *shouldReportValue = YES;
  *attributeValueToReport = expectedAttributeValue;
  } else if (!expectedAttributeValue
- && ![self _attributeDataValue:previousExpectedValue.second isEqualToDataValue:_readCache[attributePath]]) {
+ && ![self _attributeDataValue:previousExpectedValue[MTRDeviceExpectedValueFieldValueIndex]
+ isEqualToDataValue:_readCache[attributePath]]) {
  // Case of removing expected value that is different than read cache - report read cache value
  *shouldReportValue = YES;
  *attributeValueToReport = _readCache[attributePath];
@@ -1031,15 +1039,24 @@ - (void)_setExpectedValue:(NSDictionary<NSString *, id> *)expectedAttributeValue
  }
 
  if (expectedAttributeValue) {
- _expectedValueCache[attributePath] = [MTRPair pairWithFirst:expirationTime second:expectedAttributeValue];
- } else {
- _expectedValueCache[attributePath] = nil;
+ uint64_t expectedValueIDToReturn = _expectedValueNextID++;
+ _expectedValueCache[attributePath] = @[ expirationTime, expectedAttributeValue, @(expectedValueIDToReturn) ];
+ if (expectedValueID) {
+ *expectedValueID = expectedValueIDToReturn;
+ }
+ } else if (previousExpectedValue) {
+ // Remove previous expected value only if it's from the same setExpectedValues operation
+ NSNumber * previousExpectedValueID = previousExpectedValue[MTRDeviceExpectedValueFieldIDIndex];
+ if (previousExpectedValueID.unsignedLongLongValue == *expectedValueID) {
+ _expectedValueCache[attributePath] = nil;
+ }
  }
 }
 
 // assume lock is held
 - (NSArray *)_getAttributesToReportWithNewExpectedValues:(NSArray<NSDictionary<NSString *, id> *> *)expectedAttributeValues
  expirationTime:(NSDate *)expirationTime
+ expectedValueID:(uint64_t *)expectedValueID
 {
  os_unfair_lock_assert_owner(&self->_lock);
 
@@ -1055,7 +1072,8 @@ - (NSArray *)_getAttributesToReportWithNewExpectedValues:(NSArray<NSDictionary<N
  attributePath:attributePath
  expirationTime:expirationTime
  shouldReportValue:&shouldReportValue
- attributeValueToReport:&attributeValueToReport];
+ attributeValueToReport:&attributeValueToReport
+ expectedValueID:expectedValueID];
 
  if (shouldReportValue) {
  [attributesToReport addObject:@{ MTRAttributePathKey : attributePath, MTRDataKey : attributeValueToReport }];
@@ -1069,6 +1087,13 @@ - (NSArray *)_getAttributesToReportWithNewExpectedValues:(NSArray<NSDictionary<N
 }
 
 - (void)setExpectedValues:(NSArray<NSDictionary<NSString *, id> *> *)values expectedValueInterval:(NSNumber *)expectedValueInterval
+{
+ [self setExpectedValues:values expectedValueInterval:expectedValueInterval expectedValueID:nil];
+}
+
+- (void)setExpectedValues:(NSArray<NSDictionary<NSString *, id> *> *)values
+ expectedValueInterval:(NSNumber *)expectedValueInterval
+ expectedValueID:(uint64_t *)expectedValueID
 {
  // since NSTimeInterval is in seconds, convert ms into seconds in double
  NSDate * expirationTime = [NSDate dateWithTimeIntervalSinceNow:expectedValueInterval.doubleValue / 1000];
@@ -1079,25 +1104,46 @@ - (void)setExpectedValues:(NSArray<NSDictionary<NSString *, id> *> *)values expe
  os_unfair_lock_lock(&self->_lock);
 
  // _getAttributesToReportWithNewExpectedValues will log attribute paths reported
- NSArray * attributesToReport = [self _getAttributesToReportWithNewExpectedValues:values expirationTime:expirationTime];
+ NSArray * attributesToReport = [self _getAttributesToReportWithNewExpectedValues:values
+ expirationTime:expirationTime
+ expectedValueID:expectedValueID];
  [self _reportAttributes:attributesToReport];
 
  [self _checkExpiredExpectedValues];
  os_unfair_lock_unlock(&self->_lock);
 }
 
-- (void)removeExpectedValuesForAttributePath:(MTRAttributePath *)attributePath
+- (void)removeExpectedValuesForAttributePaths:(NSArray<MTRAttributePath *> *)attributePaths
+ expectedValueID:(uint64_t)expectedValueID
 {
  os_unfair_lock_lock(&self->_lock);
+ for (MTRAttributePath * attributePath in attributePaths) {
+ [self _removeExpectedValueForAttributePath:attributePath expectedValueID:expectedValueID];
+ }
+ os_unfair_lock_unlock(&self->_lock);
+}
+
+- (void)removeExpectedValueForAttributePath:(MTRAttributePath *)attributePath expectedValueID:(uint64_t)expectedValueID
+{
+ os_unfair_lock_lock(&self->_lock);
+ [self _removeExpectedValueForAttributePath:attributePath expectedValueID:expectedValueID];
+ os_unfair_lock_unlock(&self->_lock);
+}
+
+- (void)_removeExpectedValueForAttributePath:(MTRAttributePath *)attributePath expectedValueID:(uint64_t)expectedValueID
+{
+ os_unfair_lock_assert_owner(&self->_lock);
+
  BOOL shouldReportValue;
  NSDictionary<NSString *, id> * attributeValueToReport;
  [self _setExpectedValue:nil
  attributePath:attributePath
  expirationTime:nil
  shouldReportValue:&shouldReportValue
- attributeValueToReport:&attributeValueToReport];
+ attributeValueToReport:&attributeValueToReport
+ expectedValueID:&expectedValueID];
 
- MTR_LOG_INFO("%@ remove expected values for path %@ should report %@", self, attributePath, shouldReportValue ? @"YES" : @"NO");
+ MTR_LOG_INFO("%@ remove expected value for path %@ should report %@", self, attributePath, shouldReportValue ? @"YES" : @"NO");
 
  if (shouldReportValue) {
  if (attributeValueToReport) {
@@ -1106,7 +1152,6 @@ - (void)removeExpectedValuesForAttributePath:(MTRAttributePath *)attributePath
  [self _reportAttributes:@[ @{ MTRAttributePathKey : attributePath } ]];
  }
  }
- os_unfair_lock_unlock(&self->_lock);
 }
 
 - (MTRBaseDevice *)newBaseDevice

src/darwin/Framework/CHIPTests/MTRDeviceTests.m

@@ -1405,7 +1405,7 @@ - (void)test017_TestMTRDeviceBasics
  // Before resubscribe, first test write failure and expected value effects
  NSNumber * testEndpointID = @(1);
  NSNumber * testClusterID = @(8);
- NSNumber * testAttributeID = @(10000);
+ NSNumber * testAttributeID = @(10000); // choose a nonexistent attribute to cause a failure
  XCTestExpectation * expectedValueReportedExpectation = [self expectationWithDescription:@"Expected value reported"];
  XCTestExpectation * expectedValueRemovedExpectation = [self expectationWithDescription:@"Expected value removed"];
  delegate.onAttributeDataReceived = ^(NSArray<NSDictionary<NSString *, id> *> * attributeReport) {
@@ -1430,10 +1430,11 @@ - (void)test017_TestMTRDeviceBasics
  clusterID:testClusterID
  attributeID:testAttributeID
  value:writeValue
- expectedValueInterval:@(20)
+ expectedValueInterval:@(20000)
  timedWriteTimeout:nil];
 
- // expected value interval is 20 but expect it get reverted immediately as the write fails
+ // expected value interval is 20s but expect it get reverted immediately as the write fails because it's writing to a
+ // nonexistent attribute
  [self waitForExpectations:@[ expectedValueReportedExpectation, expectedValueRemovedExpectation ] timeout:5 enforceOrder:YES];
 
  // reset the onAttributeDataReceived to validate the following resubscribe test