Chapter 11 - Chat App/ChatAppFinished/Pods/FirebaseDatabase/Firebase/Database/Core/FRepoManager.m
/*
 * 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 <FirebaseCore/FIRLogger.h>
#import "FRepoManager.h"
#import "FRepo.h"
#import "FIRDatabaseQuery_Private.h"
#import "FAtomicNumber.h"
#import "FIRDatabaseConfig_Private.h"
#import "FIRDatabase_Private.h"

@implementation FRepoManager

typedef NSMutableDictionary<NSString *,
                            NSMutableDictionary<FRepoInfo *, FRepo *> *>
    FRepoDictionary;

+ (FRepoDictionary *)configs {
    static dispatch_once_t pred = 0;
    static FRepoDictionary *configs;
    dispatch_once(&pred, ^{
        configs = [NSMutableDictionary dictionary];
    });
    return configs;
}

/**
 * Used for legacy unit tests.  The public API should go through FirebaseDatabase which
 * calls createRepo.
 */
+ (FRepo *) getRepo:(FRepoInfo *)repoInfo config:(FIRDatabaseConfig *)config {
    [config freeze];
    FRepoDictionary *configs = [FRepoManager configs];
    @synchronized(configs) {
        NSMutableDictionary<FRepoInfo *, FRepo *> *repos = configs[config.sessionIdentifier];
        if (!repos || repos[repoInfo] == nil) {
            // Calling this should create the repo.
            [FIRDatabase createDatabaseForTests:repoInfo config:config];
        }

        return configs[config.sessionIdentifier][repoInfo];
    }
}

+ (FRepo *) createRepo:(FRepoInfo *)repoInfo config:(FIRDatabaseConfig *)config database:(FIRDatabase *)database {
    [config freeze];
    FRepoDictionary *configs = [FRepoManager configs];
    @synchronized(configs) {
        NSMutableDictionary<FRepoInfo *, FRepo *> *repos =
            configs[config.sessionIdentifier];
        if (!repos) {
            repos = [NSMutableDictionary dictionary];
            configs[config.sessionIdentifier] = repos;
        }
        FRepo *repo = repos[repoInfo];
        if (repo == nil) {
            repo = [[FRepo alloc] initWithRepoInfo:repoInfo config:config database:database];
            repos[repoInfo] = repo;
            return repo;
        } else {
            [NSException raise:@"RepoExists" format:@"createRepo called for Repo that already exists."];
            return nil;
        }
    }
}

+ (void) interrupt:(FIRDatabaseConfig *)config {
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        FRepoDictionary *configs = [FRepoManager configs];
        NSMutableDictionary<FRepoInfo *, FRepo *> *repos = configs[config.sessionIdentifier];
        for (FRepo *repo in [repos allValues]) {
            [repo interrupt];
        }
    });
}

+ (void) interruptAll {
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        FRepoDictionary *configs = [FRepoManager configs];
        for (NSMutableDictionary<FRepoInfo *, FRepo *> *repos in [configs allValues]) {
              for (FRepo *repo in [repos allValues]) {
                    [repo interrupt];
              }
        }
    });
}

+ (void) resume:(FIRDatabaseConfig *)config {
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        FRepoDictionary *configs = [FRepoManager configs];
        NSMutableDictionary<FRepoInfo *, FRepo *> *repos = configs[config.sessionIdentifier];
        for (FRepo *repo in [repos allValues]) {
            [repo resume];
        }
    });
}

+ (void) resumeAll {
    dispatch_async([FIRDatabaseQuery sharedQueue], ^{
        FRepoDictionary *configs = [FRepoManager configs];
        for (NSMutableDictionary<FRepoInfo *, FRepo *> *repos in [configs allValues]) {
            for (FRepo *repo in [repos allValues]) {
                [repo resume];
            }
        }
    });
}

+ (void)disposeRepos:(FIRDatabaseConfig *)config {
    // Do this synchronously to make sure we release our references to LevelDB before returning, allowing LevelDB
    // to close and release its exclusive locks.
    dispatch_sync([FIRDatabaseQuery sharedQueue], ^{
        FFLog(@"I-RDB040001", @"Disposing all repos for Config with name %@", config.sessionIdentifier);
        NSMutableDictionary *configs = [FRepoManager configs];
        for (FRepo* repo in [configs[config.sessionIdentifier] allValues]) {
            [repo dispose];
        }
        [configs removeObjectForKey:config.sessionIdentifier];
    });
}

@end
