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/*
* 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 "FIRLogger.h"
#import "FPersistenceManager.h"
#import "FLevelDBStorageEngine.h"
#import "FCacheNode.h"
#import "FIndexedNode.h"
#import "FTrackedQueryManager.h"
#import "FTrackedQuery.h"
#import "FUtilities.h"
#import "FPruneForest.h"
#import "FClock.h"
@interface FPersistenceManager ()
@property (nonatomic, strong) id<FStorageEngine> storageEngine;
@property (nonatomic, strong) id<FCachePolicy> cachePolicy;
@property (nonatomic, strong) FTrackedQueryManager *trackedQueryManager;
@property (nonatomic) NSUInteger serverCacheUpdatesSinceLastPruneCheck;
@end
@implementation FPersistenceManager
- (id)initWithStorageEngine:(id<FStorageEngine>)storageEngine cachePolicy:(id<FCachePolicy>)cachePolicy {
self = [super init];
if (self != nil) {
self->_storageEngine = storageEngine;
self->_cachePolicy = cachePolicy;
self->_trackedQueryManager = [[FTrackedQueryManager alloc] initWithStorageEngine:self.storageEngine
clock:[FSystemClock clock]];
}
return self;
}
- (void)close {
[self.storageEngine close];
self.storageEngine = nil;
self.trackedQueryManager = nil;
}
- (void)saveUserOverwrite:(id<FNode>)node atPath:(FPath *)path writeId:(NSUInteger)writeId {
[self.storageEngine saveUserOverwrite:node atPath:path writeId:writeId];
}
- (void)saveUserMerge:(FCompoundWrite *)merge atPath:(FPath *)path writeId:(NSUInteger)writeId {
[self.storageEngine saveUserMerge:merge atPath:path writeId:writeId];
}
- (void)removeUserWrite:(NSUInteger)writeId {
[self.storageEngine removeUserWrite:writeId];
}
- (void)removeAllUserWrites {
[self.storageEngine removeAllUserWrites];
}
- (NSArray *)userWrites {
return [self.storageEngine userWrites];
}
- (FCacheNode *)serverCacheForQuery:(FQuerySpec *)query {
NSSet *trackedKeys;
BOOL complete;
// TODO[offline]: Should we use trackedKeys to find out if this location is a child of a complete query?
if ([self.trackedQueryManager isQueryComplete:query]) {
complete = YES;
FTrackedQuery *trackedQuery = [self.trackedQueryManager findTrackedQuery:query];
if (!query.loadsAllData && trackedQuery.isComplete) {
trackedKeys = [self.storageEngine trackedQueryKeysForQuery:trackedQuery.queryId];
} else {
trackedKeys = nil;
}
} else {
complete = NO;
trackedKeys = [self.trackedQueryManager knownCompleteChildrenAtPath:query.path];
}
id<FNode> node;
if (trackedKeys != nil) {
node = [self.storageEngine serverCacheForKeys:trackedKeys atPath:query.path];
} else {
node = [self.storageEngine serverCacheAtPath:query.path];
}
FIndexedNode *indexedNode = [FIndexedNode indexedNodeWithNode:node index:query.index];
return [[FCacheNode alloc] initWithIndexedNode:indexedNode isFullyInitialized:complete isFiltered:(trackedKeys != nil)];
}
- (void)updateServerCacheWithNode:(id<FNode>)node forQuery:(FQuerySpec *)query {
BOOL merge = !query.loadsAllData;
[self.storageEngine updateServerCache:node atPath:query.path merge:merge];
[self setQueryComplete:query];
[self doPruneCheckAfterServerUpdate];
}
- (void)updateServerCacheWithMerge:(FCompoundWrite *)merge atPath:(FPath *)path {
[self.storageEngine updateServerCacheWithMerge:merge atPath:path];
[self doPruneCheckAfterServerUpdate];
}
- (void)applyUserMerge:(FCompoundWrite *)merge toServerCacheAtPath:(FPath *)path {
// TODO[offline]: rework this to be more efficient
[merge enumerateWrites:^(FPath *relativePath, id<FNode> node, BOOL *stop) {
[self applyUserWrite:node toServerCacheAtPath:[path child:relativePath]];
}];
}
- (void)applyUserWrite:(id<FNode>)write toServerCacheAtPath:(FPath *)path {
// This is a hack to guess whether we already cached this because we got a server data update for this
// write via an existing active default query. If we didn't, then we'll manually cache this and add a
// tracked query to mark it complete and keep it cached.
// Unfortunately this is just a guess and it's possible that we *did* get an update (e.g. via a filtered
// query) and by overwriting the cache here, we'll actually store an incorrect value (e.g. in the case
// that we wrote a ServerValue.TIMESTAMP and the server resolved it to a different value).
// TODO[offline]: Consider reworking.
if (![self.trackedQueryManager hasActiveDefaultQueryAtPath:path]) {
[self.storageEngine updateServerCache:write atPath:path merge:NO];
[self.trackedQueryManager ensureCompleteTrackedQueryAtPath:path];
}
}
- (void)setQueryComplete:(FQuerySpec *)query {
if (query.loadsAllData) {
[self.trackedQueryManager setQueriesCompleteAtPath:query.path];
} else {
[self.trackedQueryManager setQueryComplete:query];
}
}
- (void)setQueryActive:(FQuerySpec *)spec {
[self.trackedQueryManager setQueryActive:spec];
}
- (void)setQueryInactive:(FQuerySpec *)spec {
[self.trackedQueryManager setQueryInactive:spec];
}
- (void)doPruneCheckAfterServerUpdate {
self.serverCacheUpdatesSinceLastPruneCheck++;
if ([self.cachePolicy shouldCheckCacheSize:self.serverCacheUpdatesSinceLastPruneCheck]) {
FFDebug(@"I-RDB078001", @"Reached prune check threshold. Checking...");
NSDate *date = [NSDate date];
self.serverCacheUpdatesSinceLastPruneCheck = 0;
BOOL canPrune = YES;
NSUInteger cacheSize = [self.storageEngine serverCacheEstimatedSizeInBytes];
FFDebug(@"I-RDB078002", @"Server cache size: %lu", (unsigned long)cacheSize);
while (canPrune && [self.cachePolicy shouldPruneCacheWithSize:cacheSize
numberOfTrackedQueries:self.trackedQueryManager.numberOfPrunableQueries]) {
FPruneForest *pruneForest = [self.trackedQueryManager pruneOldQueries:self.cachePolicy];
if (pruneForest.prunesAnything) {
[self.storageEngine pruneCache:pruneForest atPath:[FPath empty]];
} else {
canPrune = NO;
}
cacheSize = [self.storageEngine serverCacheEstimatedSizeInBytes];
FFDebug(@"I-RDB078003", @"Cache size after pruning: %lu", (unsigned long)cacheSize);
}
FFDebug(@"I-RDB078004", @"Pruning round took %fms", [date timeIntervalSinceNow]*-1000);
}
}
- (void)setTrackedQueryKeys:(NSSet *)keys forQuery:(FQuerySpec *)query {
NSAssert(!query.loadsAllData, @"We should only track keys for filtered queries");
FTrackedQuery *trackedQuery = [self.trackedQueryManager findTrackedQuery:query];
NSAssert(trackedQuery.isActive, @"We only expect tracked keys for currently-active queries.");
[self.storageEngine setTrackedQueryKeys:keys forQueryId:trackedQuery.queryId];
}
- (void)updateTrackedQueryKeysWithAddedKeys:(NSSet *)added removedKeys:(NSSet *)removed forQuery:(FQuerySpec *)query {
NSAssert(!query.loadsAllData, @"We should only track keys for filtered queries");
FTrackedQuery *trackedQuery = [self.trackedQueryManager findTrackedQuery:query];
NSAssert(trackedQuery.isActive, @"We only expect tracked keys for currently-active queries.");
[self.storageEngine updateTrackedQueryKeysWithAddedKeys:added removedKeys:removed forQueryId:trackedQuery.queryId];
}
@end
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