--- /dev/null
+/*
+ * 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 "FIRMessaging.h"
+#import "FIRMessagingCheckinService.h"
+#import "FIRMessagingTopicsCommon.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ * An asynchronous NSOperation subclass which performs a single network request for a topic
+ * subscription operation. Once completed, it calls its provided completion handler.
+ */
+@interface FIRMessagingTopicOperation : NSOperation
+
+@property(nonatomic, readonly, copy) NSString *topic;
+@property(nonatomic, readonly, assign) FIRMessagingTopicAction action;
+@property(nonatomic, readonly, copy) NSString *token;
+@property(nonatomic, readonly, copy, nullable) NSDictionary *options;
+@property(nonatomic, readonly, strong) FIRMessagingCheckinService *checkinService;
+
+- (instancetype)initWithTopic:(NSString *)topic
+ action:(FIRMessagingTopicAction)action
+ token:(NSString *)token
+ options:(nullable NSDictionary *)options
+ checkinService:(FIRMessagingCheckinService *)checkinService
+ completion:(FIRMessagingTopicOperationCompletion)completion;
+
+@end
+
+NS_ASSUME_NONNULL_END