GoogleSignIn-iOS/GoogleSignIn/Sources/GIDAppAuthFetcherAuthorizationWithEMMSupport.m

/*
 * Copyright 2022 Google LLC
 *
 * 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 <TargetConditionals.h>

#if TARGET_OS_IOS && !TARGET_OS_MACCATALYST

#import "GoogleSignIn/Sources/GIDAppAuthFetcherAuthorizationWithEMMSupport.h"

#import "GoogleSignIn/Sources/GIDEMMSupport.h"

#ifdef SWIFT_PACKAGE
@import AppAuth;
@import GTMAppAuth;
#else
#import <AppAuth/AppAuth.h>
#import <GTMAppAuth/GTMAppAuth.h>
#endif

NS_ASSUME_NONNULL_BEGIN

// The specialized GTMAppAuthFetcherAuthorization delegate that handles potential EMM error
// responses.
@interface GIDAppAuthFetcherAuthorizationEMMChainedDelegate : NSObject

// Initializes with chained delegate and selector.
- (instancetype)initWithDelegate:(id)delegate selector:(SEL)selector;

// The callback method for GTMAppAuthFetcherAuthorization to invoke.
- (void)authentication:(GTMAppAuthFetcherAuthorization *)auth
               request:(NSMutableURLRequest *)request
     finishedWithError:(nullable NSError *)error;

@end

@implementation GIDAppAuthFetcherAuthorizationEMMChainedDelegate {
  // We use a weak reference here to match GTMAppAuthFetcherAuthorization.
  __weak id _delegate;
  SEL _selector;
  // We need to maintain a reference to the chained delegate because GTMAppAuthFetcherAuthorization
  // only keeps a weak reference.
  GIDAppAuthFetcherAuthorizationEMMChainedDelegate *_retained_self;
}

- (instancetype)initWithDelegate:(id)delegate selector:(SEL)selector {
  self = [super init];
  if (self) {
    _delegate = delegate;
    _selector = selector;
    _retained_self = self;
  }
  return self;
}

- (void)authentication:(GTMAppAuthFetcherAuthorization *)auth
               request:(NSMutableURLRequest *)request
     finishedWithError:(nullable NSError *)error {
  [GIDEMMSupport handleTokenFetchEMMError:error completion:^(NSError *_Nullable error) {
    if (!self->_delegate || !self->_selector) {
      return;
    }
    NSMethodSignature *signature = [self->_delegate methodSignatureForSelector:self->_selector];
    if (!signature) {
      return;
    }
    id argument1 = auth;
    id argument2 = request;
    id argument3 = error;
    NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature];
    [invocation setTarget:self->_delegate];  // index 0
    [invocation setSelector:self->_selector];  // index 1
    [invocation setArgument:&argument1 atIndex:2];
    [invocation setArgument:&argument2 atIndex:3];
    [invocation setArgument:&argument3 atIndex:4];
    [invocation invoke];
  }];
  // Prepare to deallocate the chained delegate instance because the above block will retain the
  // iVar references it uses.
  _retained_self = nil;
}

@end

@implementation GIDAppAuthFetcherAuthorizationWithEMMSupport

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-implementations"
- (void)authorizeRequest:(nullable NSMutableURLRequest *)request
                delegate:(id)delegate
       didFinishSelector:(SEL)sel {
#pragma clang diagnostic pop
  GIDAppAuthFetcherAuthorizationEMMChainedDelegate *chainedDelegate =
      [[GIDAppAuthFetcherAuthorizationEMMChainedDelegate alloc] initWithDelegate:delegate
                                                                        selector:sel];
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
  [super authorizeRequest:request
                 delegate:chainedDelegate
        didFinishSelector:@selector(authentication:request:finishedWithError:)];
#pragma clang diagnostic pop
}

- (void)authorizeRequest:(nullable NSMutableURLRequest *)request
       completionHandler:(GTMAppAuthFetcherAuthorizationCompletion)handler {
  [super authorizeRequest:request completionHandler:^(NSError *_Nullable error) {
    [GIDEMMSupport handleTokenFetchEMMError:error completion:^(NSError *_Nullable error) {
      handler(error);
    }];
  }];
}

@end

NS_ASSUME_NONNULL_END

#endif // TARGET_OS_IOS && !TARGET_OS_MACCATALYST