Proyectos de Subversion Iphone Microlearning

// 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/Sources/FIRAppAssociationRegistration.h"

#import <objc/runtime.h>

@implementation FIRAppAssociationRegistration

+ (nullable id)registeredObjectWithHost:(id)host

                                    key:(NSString *)key

                          creationBlock:(id _Nullable (^)(void))creationBlock {

  @synchronized(self) {

    SEL dictKey = @selector(registeredObjectWithHost:key:creationBlock:);

    NSMutableDictionary<NSString *, id> *objectsByKey = objc_getAssociatedObject(host, dictKey);

    if (!objectsByKey) {

      objectsByKey = [[NSMutableDictionary alloc] init];

      objc_setAssociatedObject(host, dictKey, objectsByKey, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

    }

    id obj = objectsByKey[key];

    NSValue *creationBlockBeingCalled = [NSValue valueWithPointer:dictKey];

    if (obj) {

      if ([creationBlockBeingCalled isEqual:obj]) {

        [NSException raise:@"Reentering registeredObjectWithHost:key:creationBlock: not allowed"

                    format:@"host: %@ key: %@", host, key];

      }

      return obj;

    }

    objectsByKey[key] = creationBlockBeingCalled;

    obj = creationBlock();

    objectsByKey[key] = obj;

    return obj;

  }

}

@end