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Added a method in iOS Object Detector to process packets for callbacks

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This commit is contained in:
Prianka Liz Kariat 2023-05-29 22:38:22 +05:30
parent 250b11f5d1
commit 6073d693d0
1 changed files with 45 additions and 43 deletions
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88
mediapipe/tasks/ios/vision/object_detector/sources/MPPObjectDetector.mm
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@ -50,12 +50,51 @@ static NSString *const kTaskName = @"objectDetector";
@interface MPPObjectDetector () {
/** iOS Vision Task Runner */
MPPVisionTaskRunner *_visionTaskRunner;
dispatch_queue_t _callbackQueue;
}
@property(nonatomic, weak) id<MPPObjectDetectorLiveStreamDelegate> objectDetectorLiveStreamDelegate;
@end
@implementation MPPObjectDetector
- (void)processLiveStreamResult:(absl::StatusOr<PacketMap>)liveStreamResult {
if (![self.objectDetectorLiveStreamDelegate
respondsToSelector:@selector(objectDetector:
didFinishDetectionWithResult:timestampInMilliseconds:error:)]) {
return;
}
NSError *callbackError = nil;
if (![MPPCommonUtils checkCppError:liveStreamResult.status() toError:&callbackError]) {
dispatch_async(_callbackQueue, ^{
[self.objectDetectorLiveStreamDelegate objectDetector:self
didFinishDetectionWithResult:nil
timestampInMilliseconds:Timestamp::Unset().Value()
error:callbackError];
});
return;
}
PacketMap &outputPacketMap = liveStreamResult.value();
if (outputPacketMap[kImageOutStreamName.cppString].IsEmpty()) {
return;
}
MPPObjectDetectorResult *result = [MPPObjectDetectorResult
objectDetectorResultWithDetectionsPacket:
outputPacketMap:[kDetectionsStreamName.cppString]];
NSInteger timeStampInMilliseconds =
outputPacketMap[kImageOutStreamName.cppString].Timestamp().Value() /
kMicroSecondsPerMilliSecond;
dispatch_async(_callbackQueue, ^{
[self.objectDetectorLiveStreamDelegate objectDetector:self
didFinishDetectionWithResult:result
timestampInMilliseconds:timeStampInMilliseconds
error:callbackError];
});
}
- (instancetype)initWithOptions:(MPPObjectDetectorOptions *)options error:(NSError **)error {
self = [super init];
if (self) {
@ -82,55 +121,18 @@ static NSString *const kTaskName = @"objectDetector";
if (options.objectDetectorLiveStreamDelegate) {
_objectDetectorLiveStreamDelegate = options.objectDetectorLiveStreamDelegate;
// Capturing `self` as weak in order to avoid `self` being kept in memory
// and cause a retain cycle, after self is set to `nil`.
MPPObjectDetector *__weak weakSelf = self;
// Create a private serial dispatch queue in which the delegate method will be called
// asynchronously. This is to ensure that if the client performs a long running operation in
// the delegate method, the queue on which the C++ callbacks is invoked is not blocked and is
// freed up to continue with its operations.
dispatch_queue_t callbackQueue = dispatch_queue_create(
_callbackQueue = dispatch_queue_create(
[MPPVisionTaskRunner uniqueDispatchQueueNameWithSuffix:kTaskName], NULL);
packetsCallback = [=](absl::StatusOr<PacketMap> statusOrPackets) {
if (!weakSelf) {
return;
}
if (![weakSelf.objectDetectorLiveStreamDelegate
respondsToSelector:@selector
(objectDetector:didFinishDetectionWithResult:timestampInMilliseconds:error:)]) {
return;
}
NSError *callbackError = nil;
if (![MPPCommonUtils checkCppError:statusOrPackets.status() toError:&callbackError]) {
dispatch_async(callbackQueue, ^{
[weakSelf.objectDetectorLiveStreamDelegate objectDetector:weakSelf
didFinishDetectionWithResult:nil
timestampInMilliseconds:Timestamp::Unset().Value()
error:callbackError];
});
return;
}
PacketMap &outputPacketMap = statusOrPackets.value();
if (outputPacketMap[kImageOutStreamName.cppString].IsEmpty()) {
return;
}
MPPObjectDetectorResult *result = [MPPObjectDetectorResult
objectDetectorResultWithDetectionsPacket:statusOrPackets
.value()[kDetectionsStreamName.cppString]];
NSInteger timeStampInMilliseconds =
outputPacketMap[kImageOutStreamName.cppString].Timestamp().Value() /
kMicroSecondsPerMilliSecond;
dispatch_async(callbackQueue, ^{
[weakSelf.objectDetectorLiveStreamDelegate objectDetector:weakSelf
didFinishDetectionWithResult:result
timestampInMilliseconds:timeStampInMilliseconds
error:callbackError];
});
// Capturing `self` as weak in order to avoid `self` being kept in memory
// and cause a retain cycle, after self is set to `nil`.
MPPObjectDetector *__weak weakSelf = self;
packetsCallback = [=](absl::StatusOr<PacketMap> liveStreamResult) {
[weakSelf processLiveStreamResult:liveStreamResult];
};
}