use weak references to apollo client

Author: Gui Sabran

Sources/Apollo/ApolloClient.swift

@@ -64,7 +64,10 @@ public class ApolloClient {
   }
 
   fileprivate func send<Operation: GraphQLOperation>(operation: Operation, shouldPublishResultToStore: Bool, context: UnsafeMutableRawPointer?, resultHandler: @escaping GraphQLResultHandler<Operation.Data>) -> Cancellable {
-    return networkTransport.send(operation: operation) { result in
+    return networkTransport.send(operation: operation) { [weak self] result in
+      guard let self = self else {
+        return
+      }
       self.handleOperationResult(shouldPublishResultToStore: shouldPublishResultToStore,
                                  context: context,
                                  result,
@@ -90,7 +93,10 @@ public class ApolloClient {
 
       firstly {
         try response.parseResult(cacheKeyForObject: self.cacheKeyForObject)
-        }.andThen { (result, records) in
+        }.andThen { [weak self] (result, records) in
+          guard let self = self else {
+            return
+          }
           if let records = records {
             self.store.publish(records: records, context: context).catch { error in
               preconditionFailure(String(describing: error))
@@ -175,7 +181,10 @@ extension ApolloClient: ApolloClientProtocol {
       return EmptyCancellable()
     }
 
-    return uploadingTransport.upload(operation: operation, files: files) { result in
+    return uploadingTransport.upload(operation: operation, files: files) { [weak self] result in
+      guard let self = self else {
+        return
+      }
       self.handleOperationResult(shouldPublishResultToStore: true,
                                  context: context, result,
                                  resultHandler: wrappedHandler)
@@ -206,7 +215,7 @@ private func wrapResultHandler<Data>(_ resultHandler: GraphQLResultHandler<Data>
 }
 
 private final class FetchQueryOperation<Query: GraphQLQuery>: AsynchronousOperation, Cancellable {
-  let client: ApolloClient
+  weak var client: ApolloClient?
   let query: Query
   let cachePolicy: CachePolicy
   let context: UnsafeMutableRawPointer?
@@ -235,7 +244,7 @@ private final class FetchQueryOperation<Query: GraphQLQuery>: AsynchronousOperat
       return
     }
 
-    client.store.load(query: query) { result in
+    client?.store.load(query: query) { result in
       if self.isCancelled {
         self.state = .finished
         return
@@ -262,7 +271,7 @@ private final class FetchQueryOperation<Query: GraphQLQuery>: AsynchronousOperat
   }
 
   func fetchFromNetwork() {
-    networkTask = client.send(operation: query, shouldPublishResultToStore: true, context: context) { result in
+    networkTask = client?.send(operation: query, shouldPublishResultToStore: true, context: context) { result in
       self.resultHandler(result)
       self.state = .finished
       return