allow cancelling reload requests

Summary:
Make the ProgressDialog cancelable and cancel the network request / websocket connection when the user presses back.

public

Reviewed By: andreicoman11

Differential Revision: D2764788

fb-gh-sync-id: 0fdb87ba9431be5a3c453422724cd364292eff61

ReactAndroid/src/main/java/com/facebook/react/devsupport/DevServerHelper.java

@@ -91,6 +91,7 @@ public class DevServerHelper {
   private boolean mOnChangePollingEnabled;
   private @Nullable OkHttpClient mOnChangePollingClient;
   private @Nullable OnServerContentChangeListener mOnServerContentChangeListener;
+  private @Nullable Call mDownloadBundleFromURLCall;
 
   public DevServerHelper(DevInternalSettings settings) {
     mSettings = settings;
@@ -179,15 +180,29 @@ public class DevServerHelper {
     Request request = new Request.Builder()
         .url(bundleURL)
         .build();
-    Call call = mClient.newCall(request);
-    call.enqueue(new Callback() {
+    mDownloadBundleFromURLCall = Assertions.assertNotNull(mClient.newCall(request));
+    mDownloadBundleFromURLCall.enqueue(new Callback() {
       @Override
       public void onFailure(Request request, IOException e) {
+        // ignore callback if call was cancelled
+        if (mDownloadBundleFromURLCall == null || mDownloadBundleFromURLCall.isCanceled()) {
+          mDownloadBundleFromURLCall = null;
+          return;
+        }
+        mDownloadBundleFromURLCall = null;
+
         callback.onFailure(e);
       }
 
       @Override
       public void onResponse(Response response) throws IOException {
+        // ignore callback if call was cancelled
+        if (mDownloadBundleFromURLCall == null || mDownloadBundleFromURLCall.isCanceled()) {
+          mDownloadBundleFromURLCall = null;
+          return;
+        }
+        mDownloadBundleFromURLCall = null;
+
         // Check for server errors. If the server error has the expected form, fail with more info.
         if (!response.isSuccessful()) {
           String body = response.body().string();
@@ -214,6 +229,13 @@ public class DevServerHelper {
     });
   }
 
+  public void cancelDownloadBundleFromURL() {
+    if (mDownloadBundleFromURLCall != null) {
+      mDownloadBundleFromURLCall.cancel();
+      mDownloadBundleFromURLCall = null;
+    }
+  }
+
   public void isPackagerRunning(final PackagerStatusCallback callback) {
     String statusURL = createPackagerStatusURL(getDebugServerHost());
     Request request = new Request.Builder()

ReactAndroid/src/main/java/com/facebook/react/devsupport/DevSupportManager.java

@@ -629,6 +629,13 @@ public class DevSupportManager implements NativeModuleCallExceptionHandler {
         },
         Assertions.assertNotNull(mJSAppBundleName),
         mJSBundleTempFile);
+    progressDialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
+      @Override
+      public void onCancel(DialogInterface dialog) {
+        mDevServerHelper.cancelDownloadBundleFromURL();
+      }
+    });
+    progressDialog.setCancelable(true);
   }
 
   private void reload() {