diff options
Diffstat (limited to 'Firebase/Database/Core/View/Filter')
8 files changed, 650 insertions, 0 deletions
diff --git a/Firebase/Database/Core/View/Filter/FChildChangeAccumulator.h b/Firebase/Database/Core/View/Filter/FChildChangeAccumulator.h new file mode 100644 index 0000000..59b0a85 --- /dev/null +++ b/Firebase/Database/Core/View/Filter/FChildChangeAccumulator.h @@ -0,0 +1,28 @@ +/* + * Copyright 2017 Google + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#import <Foundation/Foundation.h> + +@class FChange; + + +@interface FChildChangeAccumulator : NSObject + +- (id) init; +- (void) trackChildChange:(FChange *)change; +- (NSArray *) changes; + +@end diff --git a/Firebase/Database/Core/View/Filter/FChildChangeAccumulator.m b/Firebase/Database/Core/View/Filter/FChildChangeAccumulator.m new file mode 100644 index 0000000..e43fd7c --- /dev/null +++ b/Firebase/Database/Core/View/Filter/FChildChangeAccumulator.m @@ -0,0 +1,80 @@ +/* + * Copyright 2017 Google + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#import "FChildChangeAccumulator.h" +#import "FChange.h" +#import "FIndex.h" + +@interface FChildChangeAccumulator () +@property (nonatomic, strong) NSMutableDictionary *changeMap; +@end + +@implementation FChildChangeAccumulator + +- (id) init { + self = [super init]; + if (self) { + self.changeMap = [[NSMutableDictionary alloc] init]; + } + return self; +} + +- (void) trackChildChange:(FChange *)change { + FIRDataEventType type = change.type; + NSString *childKey = change.childKey; + NSAssert(type == FIRDataEventTypeChildAdded || type == FIRDataEventTypeChildChanged || type == FIRDataEventTypeChildRemoved, @"Only child changes supported for tracking."); + NSAssert(![change.childKey isEqualToString:@".priority"], @"Changes not tracked on priority"); + if (self.changeMap[childKey] != nil) { + FChange *oldChange = [self.changeMap objectForKey:childKey]; + FIRDataEventType oldType = oldChange.type; + if (type == FIRDataEventTypeChildAdded && oldType == FIRDataEventTypeChildRemoved) { + FChange *newChange = [[FChange alloc] initWithType:FIRDataEventTypeChildChanged + indexedNode:change.indexedNode + childKey:childKey + oldIndexedNode:oldChange.indexedNode]; + [self.changeMap setObject:newChange forKey:childKey]; + } else if (type == FIRDataEventTypeChildRemoved && oldType == FIRDataEventTypeChildAdded) { + [self.changeMap removeObjectForKey:childKey]; + } else if (type == FIRDataEventTypeChildRemoved && oldType == FIRDataEventTypeChildChanged) { + FChange *newChange = [[FChange alloc] initWithType:FIRDataEventTypeChildRemoved + indexedNode:oldChange.oldIndexedNode + childKey:childKey]; + [self.changeMap setObject:newChange forKey:childKey]; + } else if (type == FIRDataEventTypeChildChanged && oldType == FIRDataEventTypeChildAdded) { + FChange *newChange = [[FChange alloc] initWithType:FIRDataEventTypeChildAdded + indexedNode:change.indexedNode + childKey:childKey]; + [self.changeMap setObject:newChange forKey:childKey]; + } else if (type == FIRDataEventTypeChildChanged && oldType == FIRDataEventTypeChildChanged) { + FChange *newChange = [[FChange alloc] initWithType:FIRDataEventTypeChildChanged + indexedNode:change.indexedNode + childKey:childKey + oldIndexedNode:oldChange.oldIndexedNode]; + [self.changeMap setObject:newChange forKey:childKey]; + } else { + NSString *reason = [NSString stringWithFormat:@"Illegal combination of changes: %@ occurred after %@", change, oldChange]; + @throw [[NSException alloc] initWithName:@"FirebaseDatabaseInternalError" reason:reason userInfo:nil]; + } + } else { + [self.changeMap setObject:change forKey:childKey]; + } +} + +- (NSArray *) changes { + return [self.changeMap allValues]; +} + +@end diff --git a/Firebase/Database/Core/View/Filter/FCompleteChildSource.h b/Firebase/Database/Core/View/Filter/FCompleteChildSource.h new file mode 100644 index 0000000..4e99045 --- /dev/null +++ b/Firebase/Database/Core/View/Filter/FCompleteChildSource.h @@ -0,0 +1,28 @@ +/* + * Copyright 2017 Google + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#import <Foundation/Foundation.h> + +@protocol FNode; +@class FNamedNode; +@protocol FIndex; + +@protocol FCompleteChildSource<NSObject> + +- (id<FNode>) completeChild:(NSString *)childKey; +- (FNamedNode *) childByIndex:(id<FIndex>)index afterChild:(FNamedNode *)child isReverse:(BOOL)reverse; + +@end diff --git a/Firebase/Database/Core/View/Filter/FIndexedFilter.h b/Firebase/Database/Core/View/Filter/FIndexedFilter.h new file mode 100644 index 0000000..5081a77 --- /dev/null +++ b/Firebase/Database/Core/View/Filter/FIndexedFilter.h @@ -0,0 +1,27 @@ +/* + * Copyright 2017 Google + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#import <Foundation/Foundation.h> +#import "FNodeFilter.h" + +@protocol FIndex; + + +@interface FIndexedFilter : NSObject<FNodeFilter> + +- (id) initWithIndex:(id<FIndex>)theIndex; + +@end diff --git a/Firebase/Database/Core/View/Filter/FIndexedFilter.m b/Firebase/Database/Core/View/Filter/FIndexedFilter.m new file mode 100644 index 0000000..44c411c --- /dev/null +++ b/Firebase/Database/Core/View/Filter/FIndexedFilter.m @@ -0,0 +1,147 @@ +/* + * Copyright 2017 Google + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#import "FNode.h" +#import "FIndexedFilter.h" +#import "FChildChangeAccumulator.h" +#import "FIndex.h" +#import "FChange.h" +#import "FChildrenNode.h" +#import "FKeyIndex.h" +#import "FEmptyNode.h" +#import "FIndexedNode.h" + +@interface FIndexedFilter () +@property (nonatomic, strong, readwrite) id<FIndex> index; +@end + +@implementation FIndexedFilter +- (id) initWithIndex:(id<FIndex>)theIndex { + self = [super init]; + if (self) { + self.index = theIndex; + } + return self; +} + +- (FIndexedNode *)updateChildIn:(FIndexedNode *)indexedNode + forChildKey:(NSString *)childKey + newChild:(id<FNode>)newChildSnap + affectedPath:(FPath *)affectedPath + fromSource:(id<FCompleteChildSource>)source + accumulator:(FChildChangeAccumulator *)optChangeAccumulator +{ + NSAssert([indexedNode hasIndex:self.index], @"The index in FIndexedNode must match the index of the filter"); + id<FNode> node = indexedNode.node; + id<FNode> oldChildSnap = [node getImmediateChild:childKey]; + + // Check if anything actually changed. + if ([[oldChildSnap getChild:affectedPath] isEqual:[newChildSnap getChild:affectedPath]]) { + // There's an edge case where a child can enter or leave the view because affectedPath was set to null. + // In this case, affectedPath will appear null in both the old and new snapshots. So we need + // to avoid treating these cases as "nothing changed." + if (oldChildSnap.isEmpty == newChildSnap.isEmpty) { + // Nothing changed. + #ifdef DEBUG + NSAssert([oldChildSnap isEqual:newChildSnap], @"Old and new snapshots should be equal."); + #endif + + return indexedNode; + } + } + if (optChangeAccumulator) { + if (newChildSnap.isEmpty) { + if ([node hasChild:childKey]) { + FChange *change = [[FChange alloc] initWithType:FIRDataEventTypeChildRemoved + indexedNode:[FIndexedNode indexedNodeWithNode:oldChildSnap] + childKey:childKey]; + [optChangeAccumulator trackChildChange:change]; + } else { + NSAssert(node.isLeafNode, @"A child remove without an old child only makes sense on a leaf node."); + } + } else if (oldChildSnap.isEmpty) { + FChange *change = [[FChange alloc] initWithType:FIRDataEventTypeChildAdded + indexedNode:[FIndexedNode indexedNodeWithNode:newChildSnap] + childKey:childKey]; + [optChangeAccumulator trackChildChange:change]; + } else { + FChange *change = [[FChange alloc] initWithType:FIRDataEventTypeChildChanged + indexedNode:[FIndexedNode indexedNodeWithNode:newChildSnap] + childKey:childKey + oldIndexedNode:[FIndexedNode indexedNodeWithNode:oldChildSnap]]; + [optChangeAccumulator trackChildChange:change]; + } + } + if (node.isLeafNode && newChildSnap.isEmpty) { + return indexedNode; + } else { + return [indexedNode updateChild:childKey withNewChild:newChildSnap]; + } +} + +- (FIndexedNode *)updateFullNode:(FIndexedNode *)oldSnap + withNewNode:(FIndexedNode *)newSnap + accumulator:(FChildChangeAccumulator *)optChangeAccumulator +{ + if (optChangeAccumulator) { + [oldSnap.node enumerateChildrenUsingBlock:^(NSString *childKey, id<FNode> childNode, BOOL *stop) { + if (![newSnap.node hasChild:childKey]) { + FChange *change = [[FChange alloc] initWithType:FIRDataEventTypeChildRemoved + indexedNode:[FIndexedNode indexedNodeWithNode:childNode] + childKey:childKey]; + [optChangeAccumulator trackChildChange:change]; + } + }]; + + [newSnap.node enumerateChildrenUsingBlock:^(NSString *childKey, id<FNode> childNode, BOOL *stop) { + if ([oldSnap.node hasChild:childKey]) { + id<FNode> oldChildSnap = [oldSnap.node getImmediateChild:childKey]; + if (![oldChildSnap isEqual:childNode]) { + FChange *change = [[FChange alloc] initWithType:FIRDataEventTypeChildChanged + indexedNode:[FIndexedNode indexedNodeWithNode:childNode] + childKey:childKey + oldIndexedNode:[FIndexedNode indexedNodeWithNode:oldChildSnap]]; + [optChangeAccumulator trackChildChange:change]; + } + } else { + FChange *change = [[FChange alloc] initWithType:FIRDataEventTypeChildAdded + indexedNode:[FIndexedNode indexedNodeWithNode:childNode] + childKey:childKey]; + [optChangeAccumulator trackChildChange:change]; + } + }]; + } + return newSnap; +} + +- (FIndexedNode *)updatePriority:(id<FNode>)priority forNode:(FIndexedNode *)oldSnap +{ + if ([oldSnap.node isEmpty]) { + return oldSnap; + } else { + return [oldSnap updatePriority:priority]; + } +} + +- (BOOL) filtersNodes { + return NO; +} + +- (id<FNodeFilter>) indexedFilter { + return self; +} + +@end diff --git a/Firebase/Database/Core/View/Filter/FLimitedFilter.h b/Firebase/Database/Core/View/Filter/FLimitedFilter.h new file mode 100644 index 0000000..1690980 --- /dev/null +++ b/Firebase/Database/Core/View/Filter/FLimitedFilter.h @@ -0,0 +1,26 @@ +/* + * Copyright 2017 Google + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#import <Foundation/Foundation.h> +#import "FNodeFilter.h" + +@class FQueryParams; + + +@interface FLimitedFilter : NSObject<FNodeFilter> + +- (id) initWithQueryParams:(FQueryParams *)params; +@end diff --git a/Firebase/Database/Core/View/Filter/FLimitedFilter.m b/Firebase/Database/Core/View/Filter/FLimitedFilter.m new file mode 100644 index 0000000..8bc6e87 --- /dev/null +++ b/Firebase/Database/Core/View/Filter/FLimitedFilter.m @@ -0,0 +1,243 @@ +/* + * Copyright 2017 Google + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#import "FLimitedFilter.h" +#import "FChildChangeAccumulator.h" +#import "FIndex.h" +#import "FRangedFilter.h" +#import "FQueryParams.h" +#import "FQueryParams.h" +#import "FNamedNode.h" +#import "FEmptyNode.h" +#import "FChildrenNode.h" +#import "FCompleteChildSource.h" +#import "FChange.h" +#import "FTreeSortedDictionary.h" + +@interface FLimitedFilter () +@property (nonatomic, strong) FRangedFilter *rangedFilter; +@property (nonatomic, strong, readwrite) id<FIndex> index; +@property (nonatomic) NSInteger limit; +@property (nonatomic) BOOL reverse; + +@end + +@implementation FLimitedFilter +- (id) initWithQueryParams:(FQueryParams *)params { + self = [super init]; + if (self) { + self.rangedFilter = [[FRangedFilter alloc] initWithQueryParams:params]; + self.index = params.index; + self.limit = params.limit; + self.reverse = !params.isViewFromLeft; + } + return self; +} + + +- (FIndexedNode *)updateChildIn:(FIndexedNode *)oldSnap + forChildKey:(NSString *)childKey + newChild:(id<FNode>)newChildSnap + affectedPath:(FPath *)affectedPath + fromSource:(id<FCompleteChildSource>)source + accumulator:(FChildChangeAccumulator *)optChangeAccumulator +{ + if (![self.rangedFilter matchesKey:childKey andNode:newChildSnap]) { + newChildSnap = [FEmptyNode emptyNode]; + } + if ([[oldSnap.node getImmediateChild:childKey] isEqual:newChildSnap]) { + // No change + return oldSnap; + } else if (oldSnap.node.numChildren < self.limit) { + return [[self.rangedFilter indexedFilter] updateChildIn:oldSnap + forChildKey:childKey + newChild:newChildSnap + affectedPath:affectedPath + fromSource:source + accumulator:optChangeAccumulator]; + } else { + return [self fullLimitUpdateNode:oldSnap + forChildKey:childKey + newChild:newChildSnap + fromSource:source + accumulator:optChangeAccumulator]; + } +} + +- (FIndexedNode *)fullLimitUpdateNode:(FIndexedNode *)oldIndexed + forChildKey:(NSString *)childKey + newChild:(id<FNode>)newChildSnap + fromSource:(id<FCompleteChildSource>)source + accumulator:(FChildChangeAccumulator *)optChangeAccumulator +{ + NSAssert(oldIndexed.node.numChildren == self.limit, @"Should have number of children equal to limit."); + + FNamedNode *windowBoundary = self.reverse ? oldIndexed.firstChild : oldIndexed.lastChild; + + BOOL inRange = [self.rangedFilter matchesKey:childKey andNode:newChildSnap]; + if ([oldIndexed.node hasChild:childKey]) { + // `childKey` was already in `oldSnap`. Figure out if it remains in the window or needs to be replaced. + id<FNode> oldChildSnap = [oldIndexed.node getImmediateChild:childKey]; + + // In case the `newChildSnap` falls outside the window, get the `nextChild` that might replace it. + FNamedNode *nextChild = [source childByIndex:self.index afterChild:windowBoundary isReverse:(BOOL)self.reverse]; + if (nextChild != nil && ([nextChild.name isEqualToString:childKey] || + [oldIndexed.node hasChild:nextChild.name])) { + // There is a weird edge case where a node is updated as part of a merge in the write tree, but hasn't + // been applied to the limited filter yet. Ignore this next child which will be updated later in + // the limited filter... + nextChild = [source childByIndex:self.index afterChild:nextChild isReverse:self.reverse]; + } + + + + // Figure out if `newChildSnap` is in range and ordered before `nextChild` + BOOL remainsInWindow = inRange && !newChildSnap.isEmpty; + remainsInWindow = remainsInWindow && (!nextChild || [self.index compareKey:nextChild.name + andNode:nextChild.node + toOtherKey:childKey + andNode:newChildSnap + reverse:self.reverse] >= NSOrderedSame); + if (remainsInWindow) { + // `newChildSnap` is ordered before `nextChild`, so it's a child changed event + if (optChangeAccumulator != nil) { + FChange *change = [[FChange alloc] initWithType:FIRDataEventTypeChildChanged + indexedNode:[FIndexedNode indexedNodeWithNode:newChildSnap] + childKey:childKey + oldIndexedNode:[FIndexedNode indexedNodeWithNode:oldChildSnap]]; + [optChangeAccumulator trackChildChange:change]; + } + return [oldIndexed updateChild:childKey withNewChild:newChildSnap]; + } else { + // `newChildSnap` is ordered after `nextChild`, so it's a child removed event + if (optChangeAccumulator != nil) { + FChange *change = [[FChange alloc] initWithType:FIRDataEventTypeChildRemoved + indexedNode:[FIndexedNode indexedNodeWithNode:oldChildSnap] + childKey:childKey]; + [optChangeAccumulator trackChildChange:change]; + } + FIndexedNode *newIndexed = [oldIndexed updateChild:childKey withNewChild:[FEmptyNode emptyNode]]; + + // We need to check if the `nextChild` is actually in range before adding it + BOOL nextChildInRange = (nextChild != nil) && [self.rangedFilter matchesKey:nextChild.name + andNode:nextChild.node]; + if (nextChildInRange) { + if (optChangeAccumulator != nil) { + FChange *change = [[FChange alloc] initWithType:FIRDataEventTypeChildAdded + indexedNode:[FIndexedNode indexedNodeWithNode:nextChild.node] + childKey:nextChild.name]; + [optChangeAccumulator trackChildChange:change]; + } + return [newIndexed updateChild:nextChild.name withNewChild:nextChild.node]; + } else { + return newIndexed; + } + } + } else if (newChildSnap.isEmpty) { + // We're deleting a node, but it was not in the window, so ignore it. + return oldIndexed; + } else if (inRange) { + // `newChildSnap` is in range, but was ordered after `windowBoundary`. If this has changed, we bump out the + // `windowBoundary` and add the `newChildSnap` + if ([self.index compareKey:windowBoundary.name + andNode:windowBoundary.node + toOtherKey:childKey + andNode:newChildSnap + reverse:self.reverse] >= NSOrderedSame) { + if (optChangeAccumulator != nil) { + FChange *removedChange = [[FChange alloc] initWithType:FIRDataEventTypeChildRemoved + indexedNode:[FIndexedNode indexedNodeWithNode:windowBoundary.node] + childKey:windowBoundary.name]; + FChange *addedChange = [[FChange alloc] initWithType:FIRDataEventTypeChildAdded + indexedNode:[FIndexedNode indexedNodeWithNode:newChildSnap] + childKey:childKey]; + [optChangeAccumulator trackChildChange:removedChange]; + [optChangeAccumulator trackChildChange:addedChange]; + } + return [[oldIndexed updateChild:childKey withNewChild:newChildSnap] updateChild:windowBoundary.name + withNewChild:[FEmptyNode emptyNode]]; + } else { + return oldIndexed; + } + } else { + // `newChildSnap` was not in range and remains not in range, so ignore it. + return oldIndexed; + } +} + +- (FIndexedNode *)updateFullNode:(FIndexedNode *)oldSnap + withNewNode:(FIndexedNode *)newSnap + accumulator:(FChildChangeAccumulator *)optChangeAccumulator +{ + __block FIndexedNode *filtered; + if (newSnap.node.isLeafNode || newSnap.node.isEmpty) { + // Make sure we have a children node with the correct index, not a leaf node + filtered = [FIndexedNode indexedNodeWithNode:[FEmptyNode emptyNode] index:self.index]; + } else { + filtered = newSnap; + // Don't support priorities on queries. + filtered = [filtered updatePriority:[FEmptyNode emptyNode]]; + FNamedNode *startPost = nil; + FNamedNode *endPost = nil; + if (self.reverse) { + startPost = self.rangedFilter.endPost; + endPost = self.rangedFilter.startPost; + } else { + startPost = self.rangedFilter.startPost; + endPost = self.rangedFilter.endPost; + } + __block BOOL foundStartPost = NO; + __block NSUInteger count = 0; + [newSnap enumerateChildrenReverse:self.reverse usingBlock:^(NSString *childKey, id<FNode> childNode, BOOL *stop) { + if (!foundStartPost && [self.index compareKey:startPost.name + andNode:startPost.node + toOtherKey:childKey + andNode:childNode + reverse:self.reverse] <= NSOrderedSame) { + // Start adding + foundStartPost = YES; + } + BOOL inRange = foundStartPost && count < self.limit; + inRange = inRange && [self.index compareKey:childKey + andNode:childNode + toOtherKey:endPost.name + andNode:endPost.node + reverse:self.reverse] <= NSOrderedSame; + if (inRange) { + count++; + } else { + filtered = [filtered updateChild:childKey withNewChild:[FEmptyNode emptyNode]]; + } + }]; + } + return [self.indexedFilter updateFullNode:oldSnap withNewNode:filtered accumulator:optChangeAccumulator]; +} + +- (FIndexedNode *)updatePriority:(id<FNode>)priority forNode:(FIndexedNode *)oldSnap +{ + // Don't support priorities on queries. + return oldSnap; +} + +- (BOOL) filtersNodes { + return YES; +} + +- (id<FNodeFilter>) indexedFilter { + return self.rangedFilter.indexedFilter; +} + +@end diff --git a/Firebase/Database/Core/View/Filter/FNodeFilter.h b/Firebase/Database/Core/View/Filter/FNodeFilter.h new file mode 100644 index 0000000..f29a85a --- /dev/null +++ b/Firebase/Database/Core/View/Filter/FNodeFilter.h @@ -0,0 +1,71 @@ +/* + * Copyright 2017 Google + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#import <Foundation/Foundation.h> + +@protocol FNode; +@class FIndexedNode; +@protocol FCompleteChildSource; +@class FChildChangeAccumulator; +@protocol FIndex; +@class FPath; + +/** +* FNodeFilter is used to update nodes and complete children of nodes while applying queries on the fly and keeping +* track of any child changes. This class does not track value changes as value changes depend on more than just the +* node itself. Different kind of queries require different kind of implementations of this interface. +*/ +@protocol FNodeFilter<NSObject> + +/** +* Update a single complete child in the snap. If the child equals the old child in the snap, this is a no-op. +* The method expects an indexed snap. +*/ +- (FIndexedNode *) updateChildIn:(FIndexedNode *)oldSnap + forChildKey:(NSString *)childKey + newChild:(id<FNode>)newChildSnap + affectedPath:(FPath *)affectedPath + fromSource:(id<FCompleteChildSource>)source + accumulator:(FChildChangeAccumulator *)optChangeAccumulator; + +/** +* Update a node in full and output any resulting change from this complete update. +*/ +- (FIndexedNode *) updateFullNode:(FIndexedNode *)oldSnap + withNewNode:(FIndexedNode *)newSnap + accumulator:(FChildChangeAccumulator *)optChangeAccumulator; + +/** +* Update the priority of the root node +*/ +- (FIndexedNode *) updatePriority:(id<FNode>)priority forNode:(FIndexedNode *)oldSnap; + +/** +* Returns true if children might be filtered due to query critiera +*/ +- (BOOL) filtersNodes; + +/** +* Returns the index filter that this filter uses to get a NodeFilter that doesn't filter any children. +*/ +@property (nonatomic, strong, readonly) id<FNodeFilter> indexedFilter; + +/** +* Returns the index that this filter uses +*/ +@property (nonatomic, strong, readonly) id<FIndex> index; + +@end |