From a14e4ca20ff73bf8429cfa3aae495f080155348d Mon Sep 17 00:00:00 2001
From: yifeizhuang <zivy@google.com>
Date: Mon, 27 Nov 2023 16:38:56 -0800
Subject: [PATCH] fix eric's 1 coment

---
 .../java/io/grpc/xds/ControlPlaneClient.java  | 19 ++++++++-----------
 .../main/java/io/grpc/xds/XdsClientImpl.java  | 10 ++++++----
 2 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/xds/src/main/java/io/grpc/xds/ControlPlaneClient.java b/xds/src/main/java/io/grpc/xds/ControlPlaneClient.java
index d0d6feea376..f11ff953027 100644
--- a/xds/src/main/java/io/grpc/xds/ControlPlaneClient.java
+++ b/xds/src/main/java/io/grpc/xds/ControlPlaneClient.java
@@ -23,7 +23,6 @@
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Stopwatch;
 import com.google.common.base.Supplier;
-import com.google.common.util.concurrent.SettableFuture;
 import com.google.protobuf.Any;
 import com.google.rpc.Code;
 import io.envoyproxy.envoy.service.discovery.v3.AggregatedDiscoveryServiceGrpc;
@@ -290,9 +289,9 @@ void onFanOut(int count) {
     }
   }
 
-  SettableFuture<Void> createFlowControlCallBack() {
+  Runnable getFlowControlCallback() {
     if (adsStream != null) {
-      return adsStream.createFlowControlCb();
+      return adsStream.getFlowControlCallback();
     }
     return null;
   }
@@ -329,10 +328,8 @@ void onFanOutDone() {
       }
     }
 
-    SettableFuture<Void> callback() {
-      SettableFuture<Void> callback = SettableFuture.create();
-      callback.addListener(callbackRunnable, syncContext);
-      return callback;
+    Runnable getCallbackRunnable() {
+      return callbackRunnable;
     }
   }
 
@@ -359,7 +356,7 @@ private abstract class AbstractAdsStream {
      * For xDS stream flow control. Sending each watcher notification increment the counter
      * {@link #onFanOut(int)}.
      * Processing completion on each watcher decrement the counter via the callback
-     * {@link #createFlowControlCb}. When all the watchers subscribed to the resources in the
+     * {@link #getFlowControlCallback}. When all the watchers subscribed to the resources in the
      * response have been notified {@link #onFanOutDone} and counter reaches zero, ads stream is
      * ready to receive the next message.
      */
@@ -367,7 +364,7 @@ private abstract class AbstractAdsStream {
 
     abstract void onResourceFanOut(int count);
 
-    abstract SettableFuture<Void> createFlowControlCb();
+    abstract Runnable getFlowControlCallback();
 
     /**
      * Sends a discovery request with the given {@code versionInfo}, {@code nonce} and
@@ -568,8 +565,8 @@ void onResourceFanOut(int count) {
     }
 
     @Override
-    SettableFuture<Void> createFlowControlCb() {
-      return flowControlCounter.callback();
+    Runnable getFlowControlCallback() {
+      return flowControlCounter.getCallbackRunnable();
     }
 
     @Override
diff --git a/xds/src/main/java/io/grpc/xds/XdsClientImpl.java b/xds/src/main/java/io/grpc/xds/XdsClientImpl.java
index 848fd1a564d..6e7f3326a64 100644
--- a/xds/src/main/java/io/grpc/xds/XdsClientImpl.java
+++ b/xds/src/main/java/io/grpc/xds/XdsClientImpl.java
@@ -568,15 +568,17 @@ void addWatcher(ResourceWatcher<T> watcher, SynchronizationContext watcherSyncCo
       if (xdsChannel != null) {
         xdsChannel.onFanOut(1);
       }
+      T savedData = data;
+      boolean savedAbsent = absent;
       watchers.get(watcher).execute(() -> {
         try {
           if (errorDescription != null) {
             watcher.onError(Status.INVALID_ARGUMENT.withDescription(errorDescription));
             return;
           }
-          if (data != null) {
+          if (savedData != null) {
             notifyWatcher(watcher, data);
-          } else if (absent) {
+          } else if (savedAbsent) {
             watcher.onResourceDoesNotExist(resource);
           }
         } finally {
@@ -587,9 +589,9 @@ void addWatcher(ResourceWatcher<T> watcher, SynchronizationContext watcherSyncCo
 
     private void callbackFlowControl() {
       if (xdsChannel != null) {
-        SettableFuture<Void> cb = xdsChannel.createFlowControlCallBack();
+        Runnable cb = xdsChannel.getFlowControlCallback();
         if (cb != null) {
-          cb.set(null);
+          cb.run();
         }
       }
     }