packages/firebase_database/ios/Classes/FirebaseDatabasePlugin.m - mirrors/plugins - Git at Google

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 #import "FirebaseDatabasePlugin.h"

 #import <Firebase/Firebase.h>

 static FlutterError *getFlutterError(NSError *error) {
   if (error == nil) return nil;

   return [FlutterError errorWithCode:[NSString stringWithFormat:@"Error %ld", error.code]
                              message:error.domain
                              details:error.localizedDescription];
 }

 static NSDictionary *getDictionaryFromError(NSError *error) {
   if (!error) {
     return nil;
   }
   return @{
     @"code" : @(error.code),
     @"message" : error.domain ?: [NSNull null],
     @"details" : error.localizedDescription ?: [NSNull null],
   };
 }

 @interface FLTFirebaseDatabasePlugin ()

 @end

 FIRDatabaseReference *getReference(FIRDatabase *database, NSDictionary *arguments) {
   NSString *path = arguments[@"path"];
   FIRDatabaseReference *ref = database.reference;
   if ([path length] > 0) ref = [ref child:path];
   return ref;
 }

 FIRDatabaseQuery *getDatabaseQuery(FIRDatabase *database, NSDictionary *arguments) {
   FIRDatabaseQuery *query = getReference(database, arguments);
   NSDictionary *parameters = arguments[@"parameters"];
   NSString *orderBy = parameters[@"orderBy"];
   if ([orderBy isEqualToString:@"child"]) {
     query = [query queryOrderedByChild:parameters[@"orderByChildKey"]];
   } else if ([orderBy isEqualToString:@"key"]) {
     query = [query queryOrderedByKey];
   } else if ([orderBy isEqualToString:@"value"]) {
     query = [query queryOrderedByValue];
   } else if ([orderBy isEqualToString:@"priority"]) {
     query = [query queryOrderedByPriority];
   }
   id startAt = parameters[@"startAt"];
   if (startAt) {
     id startAtKey = parameters[@"startAtKey"];
     if (startAtKey) {
       query = [query queryStartingAtValue:startAt childKey:startAtKey];
     } else {
       query = [query queryStartingAtValue:startAt];
     }
   }
   id endAt = parameters[@"endAt"];
   if (endAt) {
     id endAtKey = parameters[@"endAtKey"];
     if (endAtKey) {
       query = [query queryEndingAtValue:endAt childKey:endAtKey];
     } else {
       query = [query queryEndingAtValue:endAt];
     }
   }
   id equalTo = parameters[@"equalTo"];
   if (equalTo) {
     id equalToKey = parameters[@"equalToKey"];
     if (equalToKey) {
       query = [query queryEqualToValue:equalTo childKey:equalToKey];
     } else {
       query = [query queryEqualToValue:equalTo];
     }
   }
   NSNumber *limitToFirst = parameters[@"limitToFirst"];
   if (limitToFirst) {
     query = [query queryLimitedToFirst:limitToFirst.intValue];
   }
   NSNumber *limitToLast = parameters[@"limitToLast"];
   if (limitToLast) {
     query = [query queryLimitedToLast:limitToLast.intValue];
   }
   return query;
 }

 FIRDataEventType parseEventType(NSString *eventTypeString) {
   if ([@"_EventType.childAdded" isEqual:eventTypeString]) {
     return FIRDataEventTypeChildAdded;
   } else if ([@"_EventType.childRemoved" isEqual:eventTypeString]) {
     return FIRDataEventTypeChildRemoved;
   } else if ([@"_EventType.childChanged" isEqual:eventTypeString]) {
     return FIRDataEventTypeChildChanged;
   } else if ([@"_EventType.childMoved" isEqual:eventTypeString]) {
     return FIRDataEventTypeChildMoved;
   } else if ([@"_EventType.value" isEqual:eventTypeString]) {
     return FIRDataEventTypeValue;
   }
   assert(false);
   return 0;
 }

 id roundDoubles(id value) {
   // Workaround for https://github.com/firebase/firebase-ios-sdk/issues/91
   // The Firebase iOS SDK sometimes returns doubles when ints were stored.
   // We detect doubles that can be converted to ints without loss of precision
   // and convert them.
   if ([value isKindOfClass:[NSNumber class]]) {
     CFNumberType type = CFNumberGetType((CFNumberRef)value);
     if (type == kCFNumberDoubleType || type == kCFNumberFloatType) {
       if ((double)(long long)[value doubleValue] == [value doubleValue]) {
         return [NSNumber numberWithLongLong:(long long)[value doubleValue]];
       }
     }
   } else if ([value isKindOfClass:[NSArray class]]) {
     NSMutableArray *result = [NSMutableArray arrayWithCapacity:[value count]];
     [value enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
       [result addObject:roundDoubles(obj)];
     }];
     return result;
   } else if ([value isKindOfClass:[NSDictionary class]]) {
     NSMutableDictionary *result = [NSMutableDictionary dictionaryWithCapacity:[value count]];
     [value enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
       result[key] = roundDoubles(obj);
     }];
     return result;
   }
   return value;
 }

 @interface FLTFirebaseDatabasePlugin ()
 @property(nonatomic, retain) FlutterMethodChannel *channel;
 @end

 @implementation FLTFirebaseDatabasePlugin

 + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
   FlutterMethodChannel *channel =
       [FlutterMethodChannel methodChannelWithName:@"plugins.flutter.io/firebase_database"
                                   binaryMessenger:[registrar messenger]];
   FLTFirebaseDatabasePlugin *instance = [[FLTFirebaseDatabasePlugin alloc] init];
   instance.channel = channel;
   [registrar addMethodCallDelegate:instance channel:channel];
 }

 - (instancetype)init {
   self = [super init];
   if (self) {
     if (![FIRApp appNamed:@"__FIRAPP_DEFAULT"]) {
       NSLog(@"Configuring the default Firebase app...");
       [FIRApp configure];
       NSLog(@"Configured the default Firebase app %@.", [FIRApp defaultApp].name);
     }
     self.updatedSnapshots = [NSMutableDictionary new];
   }
   return self;
 }

 - (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
   FIRDatabase *database;
   NSString *appName = call.arguments[@"app"];
   NSString *databaseURL = call.arguments[@"databaseURL"];
   if (![appName isEqual:[NSNull null]] && ![databaseURL isEqual:[NSNull null]]) {
     database = [FIRDatabase databaseForApp:[FIRApp appNamed:appName] URL:databaseURL];
   } else if (![appName isEqual:[NSNull null]]) {
     database = [FIRDatabase databaseForApp:[FIRApp appNamed:appName]];
   } else if (![databaseURL isEqual:[NSNull null]]) {
     database = [FIRDatabase databaseWithURL:databaseURL];
   } else {
     database = [FIRDatabase database];
   }
   void (^defaultCompletionBlock)(NSError *, FIRDatabaseReference *) =
       ^(NSError *error, FIRDatabaseReference *ref) {
         result(getFlutterError(error));
       };
   if ([@"FirebaseDatabase#goOnline" isEqualToString:call.method]) {
     [database goOnline];
     result(nil);
   } else if ([@"FirebaseDatabase#goOffline" isEqualToString:call.method]) {
     [database goOffline];
     result(nil);
   } else if ([@"FirebaseDatabase#purgeOutstandingWrites" isEqualToString:call.method]) {
     [database purgeOutstandingWrites];
     result(nil);
   } else if ([@"FirebaseDatabase#setPersistenceEnabled" isEqualToString:call.method]) {
     NSNumber *value = call.arguments[@"enabled"];
     @try {
       database.persistenceEnabled = value.boolValue;
       result([NSNumber numberWithBool:YES]);
     } @catch (NSException *exception) {
       if ([@"FIRDatabaseAlreadyInUse" isEqualToString:exception.name]) {
         // Database is already in use, e.g. after hot reload/restart.
         result([NSNumber numberWithBool:NO]);
       } else {
         @throw;
       }
     }
   } else if ([@"FirebaseDatabase#setPersistenceCacheSizeBytes" isEqualToString:call.method]) {
     NSNumber *value = call.arguments[@"cacheSize"];
     @try {
       database.persistenceCacheSizeBytes = value.unsignedIntegerValue;
       result([NSNumber numberWithBool:YES]);
     } @catch (NSException *exception) {
       if ([@"FIRDatabaseAlreadyInUse" isEqualToString:exception.name]) {
         // Database is already in use, e.g. after hot reload/restart.
         result([NSNumber numberWithBool:NO]);
       } else {
         @throw;
       }
     }
   } else if ([@"DatabaseReference#set" isEqualToString:call.method]) {
     [getReference(database, call.arguments) setValue:call.arguments[@"value"]
                                          andPriority:call.arguments[@"priority"]
                                  withCompletionBlock:defaultCompletionBlock];
   } else if ([@"DatabaseReference#update" isEqualToString:call.method]) {
     [getReference(database, call.arguments) updateChildValues:call.arguments[@"value"]
                                           withCompletionBlock:defaultCompletionBlock];
   } else if ([@"DatabaseReference#setPriority" isEqualToString:call.method]) {
     [getReference(database, call.arguments) setPriority:call.arguments[@"priority"]
                                     withCompletionBlock:defaultCompletionBlock];
   } else if ([@"DatabaseReference#runTransaction" isEqualToString:call.method]) {
     [getReference(database, call.arguments)
         runTransactionBlock:^FIRTransactionResult *_Nonnull(FIRMutableData *_Nonnull currentData) {
           // Create semaphore to allow native side to wait while snapshot
           // updates occur on the Dart side.
           dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

           NSObject *snapshot =
               @{@"key" : currentData.key ?: [NSNull null], @"value" : currentData.value};

           __block bool shouldAbort = false;

           [self.channel invokeMethod:@"DoTransaction"
                            arguments:@{
                              @"transactionKey" : call.arguments[@"transactionKey"],
                              @"snapshot" : snapshot
                            }
                               result:^(id _Nullable result) {
                                 if ([result isKindOfClass:[FlutterError class]]) {
                                   FlutterError *flutterError = ((FlutterError *)result);
                                   NSLog(@"Error code: %@", flutterError.code);
                                   NSLog(@"Error message: %@", flutterError.message);
                                   NSLog(@"Error details: %@", flutterError.details);
                                   shouldAbort = true;
                                 } else if ([result isEqual:FlutterMethodNotImplemented]) {
                                   NSLog(@"DoTransaction not implemented on the Dart side.");
                                   shouldAbort = true;
                                 } else {
                                   [self.updatedSnapshots
                                       setObject:result
                                          forKey:call.arguments[@"transactionKey"]];
                                 }
                                 dispatch_semaphore_signal(semaphore);
                               }];

           // Wait while Dart side updates the snapshot. Incoming transactionTimeout is in
           // milliseconds so converting to nanoseconds for use with dispatch_semaphore_wait.
           long result = dispatch_semaphore_wait(
               semaphore,
               dispatch_time(DISPATCH_TIME_NOW,
                             [call.arguments[@"transactionTimeout"] integerValue] * 1000000));

           if (result == 0 && !shouldAbort) {
             // Set FIRMutableData value to value returned from the Dart side.
             currentData.value =
                 [self.updatedSnapshots objectForKey:call.arguments[@"transactionKey"]][@"value"];
           } else {
             if (result != 0) {
               NSLog(@"Transaction at %@ timed out.", [getReference(database, call.arguments) URL]);
             }
             return [FIRTransactionResult abort];
           }

           return [FIRTransactionResult successWithValue:currentData];
         }
         andCompletionBlock:^(NSError *_Nullable error, BOOL committed,
                              FIRDataSnapshot *_Nullable snapshot) {
           // Invoke transaction completion on the Dart side.
           result(@{
             @"transactionKey" : call.arguments[@"transactionKey"],
             @"error" : getDictionaryFromError(error) ?: [NSNull null],
             @"committed" : [NSNumber numberWithBool:committed],
             @"snapshot" : @{@"key" : snapshot.key ?: [NSNull null], @"value" : snapshot.value}
           });
         }];
   } else if ([@"OnDisconnect#set" isEqualToString:call.method]) {
     [getReference(database, call.arguments) onDisconnectSetValue:call.arguments[@"value"]
                                                      andPriority:call.arguments[@"priority"]
                                              withCompletionBlock:defaultCompletionBlock];
   } else if ([@"OnDisconnect#update" isEqualToString:call.method]) {
     [getReference(database, call.arguments) onDisconnectUpdateChildValues:call.arguments[@"value"]
                                                       withCompletionBlock:defaultCompletionBlock];
   } else if ([@"OnDisconnect#cancel" isEqualToString:call.method]) {
     [getReference(database, call.arguments)
         cancelDisconnectOperationsWithCompletionBlock:defaultCompletionBlock];
   } else if ([@"Query#observe" isEqualToString:call.method]) {
     FIRDataEventType eventType = parseEventType(call.arguments[@"eventType"]);
     __block FIRDatabaseHandle handle = [getDatabaseQuery(database, call.arguments)
         observeEventType:eventType
         andPreviousSiblingKeyWithBlock:^(FIRDataSnapshot *snapshot, NSString *previousSiblingKey) {
           [self.channel invokeMethod:@"Event"
                            arguments:@{
                              @"handle" : [NSNumber numberWithUnsignedInteger:handle],
                              @"snapshot" : @{
                                @"key" : snapshot.key ?: [NSNull null],
                                @"value" : roundDoubles(snapshot.value) ?: [NSNull null],
                              },
                              @"previousSiblingKey" : previousSiblingKey ?: [NSNull null],
                            }];
         }
         withCancelBlock:^(NSError *error) {
           [self.channel invokeMethod:@"Error"
                            arguments:@{
                              @"handle" : [NSNumber numberWithUnsignedInteger:handle],
                              @"error" : getDictionaryFromError(error),
                            }];
         }];
     result([NSNumber numberWithUnsignedInteger:handle]);
   } else if ([@"Query#removeObserver" isEqualToString:call.method]) {
     FIRDatabaseHandle handle = [call.arguments[@"handle"] unsignedIntegerValue];
     [getDatabaseQuery(database, call.arguments) removeObserverWithHandle:handle];
     result(nil);
   } else if ([@"Query#keepSynced" isEqualToString:call.method]) {
     NSNumber *value = call.arguments[@"value"];
     [getDatabaseQuery(database, call.arguments) keepSynced:value.boolValue];
     result(nil);
   } else {
     result(FlutterMethodNotImplemented);
   }
 }

 @end
	// Copyright 2017 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	#import "FirebaseDatabasePlugin.h"

	#import <Firebase/Firebase.h>

	static FlutterError getFlutterError(NSError error) {
	if (error == nil) return nil;

	return [FlutterError errorWithCode:[NSString stringWithFormat:@"Error %ld", error.code]
	message:error.domain
	details:error.localizedDescription];
	}

	static NSDictionary getDictionaryFromError(NSError error) {
	if (!error) {
	return nil;
	}
	return @{
	@"code" : @(error.code),
	@"message" : error.domain ?: [NSNull null],
	@"details" : error.localizedDescription ?: [NSNull null],
	};
	}

	@interface FLTFirebaseDatabasePlugin ()

	@end

	FIRDatabaseReference getReference(FIRDatabase database, NSDictionary *arguments) {
	NSString *path = arguments[@"path"];
	FIRDatabaseReference *ref = database.reference;
	if ([path length] > 0) ref = [ref child:path];
	return ref;
	}

	FIRDatabaseQuery getDatabaseQuery(FIRDatabase database, NSDictionary *arguments) {
	FIRDatabaseQuery *query = getReference(database, arguments);
	NSDictionary *parameters = arguments[@"parameters"];
	NSString *orderBy = parameters[@"orderBy"];
	if ([orderBy isEqualToString:@"child"]) {
	query = [query queryOrderedByChild:parameters[@"orderByChildKey"]];
	} else if ([orderBy isEqualToString:@"key"]) {
	query = [query queryOrderedByKey];
	} else if ([orderBy isEqualToString:@"value"]) {
	query = [query queryOrderedByValue];
	} else if ([orderBy isEqualToString:@"priority"]) {
	query = [query queryOrderedByPriority];
	}
	id startAt = parameters[@"startAt"];
	if (startAt) {
	id startAtKey = parameters[@"startAtKey"];
	if (startAtKey) {
	query = [query queryStartingAtValue:startAt childKey:startAtKey];
	} else {
	query = [query queryStartingAtValue:startAt];
	}
	}
	id endAt = parameters[@"endAt"];
	if (endAt) {
	id endAtKey = parameters[@"endAtKey"];
	if (endAtKey) {
	query = [query queryEndingAtValue:endAt childKey:endAtKey];
	} else {
	query = [query queryEndingAtValue:endAt];
	}
	}
	id equalTo = parameters[@"equalTo"];
	if (equalTo) {
	id equalToKey = parameters[@"equalToKey"];
	if (equalToKey) {
	query = [query queryEqualToValue:equalTo childKey:equalToKey];
	} else {
	query = [query queryEqualToValue:equalTo];
	}
	}
	NSNumber *limitToFirst = parameters[@"limitToFirst"];
	if (limitToFirst) {
	query = [query queryLimitedToFirst:limitToFirst.intValue];
	}
	NSNumber *limitToLast = parameters[@"limitToLast"];
	if (limitToLast) {
	query = [query queryLimitedToLast:limitToLast.intValue];
	}
	return query;
	}

	FIRDataEventType parseEventType(NSString *eventTypeString) {
	if ([@"_EventType.childAdded" isEqual:eventTypeString]) {
	return FIRDataEventTypeChildAdded;
	} else if ([@"_EventType.childRemoved" isEqual:eventTypeString]) {
	return FIRDataEventTypeChildRemoved;
	} else if ([@"_EventType.childChanged" isEqual:eventTypeString]) {
	return FIRDataEventTypeChildChanged;
	} else if ([@"_EventType.childMoved" isEqual:eventTypeString]) {
	return FIRDataEventTypeChildMoved;
	} else if ([@"_EventType.value" isEqual:eventTypeString]) {
	return FIRDataEventTypeValue;
	}
	assert(false);
	return 0;
	}

	id roundDoubles(id value) {
	// Workaround for https://github.com/firebase/firebase-ios-sdk/issues/91
	// The Firebase iOS SDK sometimes returns doubles when ints were stored.
	// We detect doubles that can be converted to ints without loss of precision
	// and convert them.
	if ([value isKindOfClass:[NSNumber class]]) {
	CFNumberType type = CFNumberGetType((CFNumberRef)value);
	if (type == kCFNumberDoubleType \|\| type == kCFNumberFloatType) {
	if ((double)(long long)[value doubleValue] == [value doubleValue]) {
	return [NSNumber numberWithLongLong:(long long)[value doubleValue]];
	}
	}
	} else if ([value isKindOfClass:[NSArray class]]) {
	NSMutableArray *result = [NSMutableArray arrayWithCapacity:[value count]];
	[value enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
	[result addObject:roundDoubles(obj)];
	}];
	return result;
	} else if ([value isKindOfClass:[NSDictionary class]]) {
	NSMutableDictionary *result = [NSMutableDictionary dictionaryWithCapacity:[value count]];
	[value enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
	result[key] = roundDoubles(obj);
	}];
	return result;
	}
	return value;
	}

	@interface FLTFirebaseDatabasePlugin ()
	@property(nonatomic, retain) FlutterMethodChannel *channel;
	@end

	@implementation FLTFirebaseDatabasePlugin

	+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
	FlutterMethodChannel *channel =
	[FlutterMethodChannel methodChannelWithName:@"plugins.flutter.io/firebase_database"
	binaryMessenger:[registrar messenger]];
	FLTFirebaseDatabasePlugin *instance = [[FLTFirebaseDatabasePlugin alloc] init];
	instance.channel = channel;
	[registrar addMethodCallDelegate:instance channel:channel];
	}

	- (instancetype)init {
	self = [super init];
	if (self) {
	if (![FIRApp appNamed:@"__FIRAPP_DEFAULT"]) {
	NSLog(@"Configuring the default Firebase app...");
	[FIRApp configure];
	NSLog(@"Configured the default Firebase app %@.", [FIRApp defaultApp].name);
	}
	self.updatedSnapshots = [NSMutableDictionary new];
	}
	return self;
	}

	- (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
	FIRDatabase *database;
	NSString *appName = call.arguments[@"app"];
	NSString *databaseURL = call.arguments[@"databaseURL"];
	if (![appName isEqual:[NSNull null]] && ![databaseURL isEqual:[NSNull null]]) {
	database = [FIRDatabase databaseForApp:[FIRApp appNamed:appName] URL:databaseURL];
	} else if (![appName isEqual:[NSNull null]]) {
	database = [FIRDatabase databaseForApp:[FIRApp appNamed:appName]];
	} else if (![databaseURL isEqual:[NSNull null]]) {
	database = [FIRDatabase databaseWithURL:databaseURL];
	} else {
	database = [FIRDatabase database];
	}
	void (^defaultCompletionBlock)(NSError , FIRDatabaseReference ) =
	^(NSError error, FIRDatabaseReference ref) {
	result(getFlutterError(error));
	};
	if ([@"FirebaseDatabase#goOnline" isEqualToString:call.method]) {
	[database goOnline];
	result(nil);
	} else if ([@"FirebaseDatabase#goOffline" isEqualToString:call.method]) {
	[database goOffline];
	result(nil);
	} else if ([@"FirebaseDatabase#purgeOutstandingWrites" isEqualToString:call.method]) {
	[database purgeOutstandingWrites];
	result(nil);
	} else if ([@"FirebaseDatabase#setPersistenceEnabled" isEqualToString:call.method]) {
	NSNumber *value = call.arguments[@"enabled"];
	@try {
	database.persistenceEnabled = value.boolValue;
	result([NSNumber numberWithBool:YES]);
	} @catch (NSException *exception) {
	if ([@"FIRDatabaseAlreadyInUse" isEqualToString:exception.name]) {
	// Database is already in use, e.g. after hot reload/restart.
	result([NSNumber numberWithBool:NO]);
	} else {
	@throw;
	}
	}
	} else if ([@"FirebaseDatabase#setPersistenceCacheSizeBytes" isEqualToString:call.method]) {
	NSNumber *value = call.arguments[@"cacheSize"];
	@try {
	database.persistenceCacheSizeBytes = value.unsignedIntegerValue;
	result([NSNumber numberWithBool:YES]);
	} @catch (NSException *exception) {
	if ([@"FIRDatabaseAlreadyInUse" isEqualToString:exception.name]) {
	// Database is already in use, e.g. after hot reload/restart.
	result([NSNumber numberWithBool:NO]);
	} else {
	@throw;
	}
	}
	} else if ([@"DatabaseReference#set" isEqualToString:call.method]) {
	[getReference(database, call.arguments) setValue:call.arguments[@"value"]
	andPriority:call.arguments[@"priority"]
	withCompletionBlock:defaultCompletionBlock];
	} else if ([@"DatabaseReference#update" isEqualToString:call.method]) {
	[getReference(database, call.arguments) updateChildValues:call.arguments[@"value"]
	withCompletionBlock:defaultCompletionBlock];
	} else if ([@"DatabaseReference#setPriority" isEqualToString:call.method]) {
	[getReference(database, call.arguments) setPriority:call.arguments[@"priority"]
	withCompletionBlock:defaultCompletionBlock];
	} else if ([@"DatabaseReference#runTransaction" isEqualToString:call.method]) {
	[getReference(database, call.arguments)
	runTransactionBlock:^FIRTransactionResult _Nonnull(FIRMutableData _Nonnull currentData) {
	// Create semaphore to allow native side to wait while snapshot
	// updates occur on the Dart side.
	dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

	NSObject *snapshot =
	@{@"key" : currentData.key ?: [NSNull null], @"value" : currentData.value};

	__block bool shouldAbort = false;

	[self.channel invokeMethod:@"DoTransaction"
	arguments:@{
	@"transactionKey" : call.arguments[@"transactionKey"],
	@"snapshot" : snapshot
	}
	result:^(id _Nullable result) {
	if ([result isKindOfClass:[FlutterError class]]) {
	FlutterError flutterError = ((FlutterError )result);
	NSLog(@"Error code: %@", flutterError.code);
	NSLog(@"Error message: %@", flutterError.message);
	NSLog(@"Error details: %@", flutterError.details);
	shouldAbort = true;
	} else if ([result isEqual:FlutterMethodNotImplemented]) {
	NSLog(@"DoTransaction not implemented on the Dart side.");
	shouldAbort = true;
	} else {
	[self.updatedSnapshots
	setObject:result
	forKey:call.arguments[@"transactionKey"]];
	}
	dispatch_semaphore_signal(semaphore);
	}];

	// Wait while Dart side updates the snapshot. Incoming transactionTimeout is in
	// milliseconds so converting to nanoseconds for use with dispatch_semaphore_wait.
	long result = dispatch_semaphore_wait(
	semaphore,
	dispatch_time(DISPATCH_TIME_NOW,
	[call.arguments[@"transactionTimeout"] integerValue] * 1000000));

	if (result == 0 && !shouldAbort) {
	// Set FIRMutableData value to value returned from the Dart side.
	currentData.value =
	[self.updatedSnapshots objectForKey:call.arguments[@"transactionKey"]][@"value"];
	} else {
	if (result != 0) {
	NSLog(@"Transaction at %@ timed out.", [getReference(database, call.arguments) URL]);
	}
	return [FIRTransactionResult abort];
	}

	return [FIRTransactionResult successWithValue:currentData];
	}
	andCompletionBlock:^(NSError *_Nullable error, BOOL committed,
	FIRDataSnapshot *_Nullable snapshot) {
	// Invoke transaction completion on the Dart side.
	result(@{
	@"transactionKey" : call.arguments[@"transactionKey"],
	@"error" : getDictionaryFromError(error) ?: [NSNull null],
	@"committed" : [NSNumber numberWithBool:committed],
	@"snapshot" : @{@"key" : snapshot.key ?: [NSNull null], @"value" : snapshot.value}
	});
	}];
	} else if ([@"OnDisconnect#set" isEqualToString:call.method]) {
	[getReference(database, call.arguments) onDisconnectSetValue:call.arguments[@"value"]
	andPriority:call.arguments[@"priority"]
	withCompletionBlock:defaultCompletionBlock];
	} else if ([@"OnDisconnect#update" isEqualToString:call.method]) {
	[getReference(database, call.arguments) onDisconnectUpdateChildValues:call.arguments[@"value"]
	withCompletionBlock:defaultCompletionBlock];
	} else if ([@"OnDisconnect#cancel" isEqualToString:call.method]) {
	[getReference(database, call.arguments)
	cancelDisconnectOperationsWithCompletionBlock:defaultCompletionBlock];
	} else if ([@"Query#observe" isEqualToString:call.method]) {
	FIRDataEventType eventType = parseEventType(call.arguments[@"eventType"]);
	__block FIRDatabaseHandle handle = [getDatabaseQuery(database, call.arguments)
	observeEventType:eventType
	andPreviousSiblingKeyWithBlock:^(FIRDataSnapshot snapshot, NSString previousSiblingKey) {
	[self.channel invokeMethod:@"Event"
	arguments:@{
	@"handle" : [NSNumber numberWithUnsignedInteger:handle],
	@"snapshot" : @{
	@"key" : snapshot.key ?: [NSNull null],
	@"value" : roundDoubles(snapshot.value) ?: [NSNull null],
	},
	@"previousSiblingKey" : previousSiblingKey ?: [NSNull null],
	}];
	}
	withCancelBlock:^(NSError *error) {
	[self.channel invokeMethod:@"Error"
	arguments:@{
	@"handle" : [NSNumber numberWithUnsignedInteger:handle],
	@"error" : getDictionaryFromError(error),
	}];
	}];
	result([NSNumber numberWithUnsignedInteger:handle]);
	} else if ([@"Query#removeObserver" isEqualToString:call.method]) {
	FIRDatabaseHandle handle = [call.arguments[@"handle"] unsignedIntegerValue];
	[getDatabaseQuery(database, call.arguments) removeObserverWithHandle:handle];
	result(nil);
	} else if ([@"Query#keepSynced" isEqualToString:call.method]) {
	NSNumber *value = call.arguments[@"value"];
	[getDatabaseQuery(database, call.arguments) keepSynced:value.boolValue];
	result(nil);
	} else {
	result(FlutterMethodNotImplemented);
	}
	}

	@end