From 5d6aa39b0b6ae44b6a3fea2a31342f478c89fcc3 Mon Sep 17 00:00:00 2001
From: Floyd Kim <for12gm@gmail.com>
Date: Fri, 31 Jul 2026 20:32:48 +0900
Subject: [PATCH] fix(android): serialize download progress events

---
 .../codepush/react/CodePushNativeModule.java  | 33 ++++++++++---------
 .../codepush/react/DownloadProgress.java      |  4 +++
 .../DownloadProgressEventDispatcher.java      | 23 +++++++++++++
 3 files changed, 45 insertions(+), 15 deletions(-)
 create mode 100644 android/app/src/main/java/com/microsoft/codepush/react/DownloadProgressEventDispatcher.java

diff --git a/android/app/src/main/java/com/microsoft/codepush/react/CodePushNativeModule.java b/android/app/src/main/java/com/microsoft/codepush/react/CodePushNativeModule.java
index 54e303a2c..d66e404f7 100644
--- a/android/app/src/main/java/com/microsoft/codepush/react/CodePushNativeModule.java
+++ b/android/app/src/main/java/com/microsoft/codepush/react/CodePushNativeModule.java
@@ -341,19 +341,28 @@ protected Void doInBackground(Void... params) {
                 try {
                     JSONObject mutableUpdatePackage = CodePushUtils.convertReadableToJsonObject(updatePackage);
                     mUpdateManager.downloadPackage(mutableUpdatePackage, mCodePush.getAssetsBundleFileName(), new DownloadProgressCallback() {
-                        private boolean hasScheduledNextFrame = false;
-                        private DownloadProgress latestDownloadProgress = null;
+                        private volatile boolean hasScheduledNextFrame = false;
+                        private volatile DownloadProgress latestDownloadProgress = null;
+                        private final DownloadProgressEventDispatcher progressEventDispatcher = new DownloadProgressEventDispatcher(
+                                new DownloadProgressEventDispatcher.EventEmitter() {
+                                    @Override
+                                    public void emit(DownloadProgress downloadProgress) {
+                                        getReactApplicationContext()
+                                                .getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
+                                                .emit(CodePushConstants.DOWNLOAD_PROGRESS_EVENT_NAME, downloadProgress.createWritableMap());
+                                    }
+                                });
 
                         @Override
                         public void call(DownloadProgress downloadProgress) {
-                            if (!notifyProgress) {
+                            if (!notifyProgress || downloadProgress == null) {
                                 return;
                             }
 
                             latestDownloadProgress = downloadProgress;
                             // If the download is completed, synchronously send the last event.
-                            if (latestDownloadProgress.isCompleted()) {
-                                dispatchDownloadProgressEvent();
+                            if (downloadProgress.isCompleted()) {
+                                progressEventDispatcher.dispatch(downloadProgress);
                                 return;
                             }
 
@@ -368,22 +377,16 @@ public void run() {
                                     ReactChoreographer.getInstance().postFrameCallback(ReactChoreographer.CallbackType.TIMERS_EVENTS, new Choreographer.FrameCallback() {
                                         @Override
                                         public void doFrame(long frameTimeNanos) {
-                                            if (!latestDownloadProgress.isCompleted()) {
-                                                dispatchDownloadProgressEvent();
+                                            try {
+                                                progressEventDispatcher.dispatch(latestDownloadProgress);
+                                            } finally {
+                                                hasScheduledNextFrame = false;
                                             }
-
-                                            hasScheduledNextFrame = false;
                                         }
                                     });
                                 }
                             });
                         }
-
-                        public void dispatchDownloadProgressEvent() {
-                            getReactApplicationContext()
-                                    .getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
-                                    .emit(CodePushConstants.DOWNLOAD_PROGRESS_EVENT_NAME, latestDownloadProgress.createWritableMap());
-                        }
                     });
 
                     JSONObject newPackage = mUpdateManager.getPackage(CodePushUtils.tryGetString(updatePackage, CodePushConstants.PACKAGE_HASH_KEY));
diff --git a/android/app/src/main/java/com/microsoft/codepush/react/DownloadProgress.java b/android/app/src/main/java/com/microsoft/codepush/react/DownloadProgress.java
index ecad8ddd9..c2f20cfb2 100644
--- a/android/app/src/main/java/com/microsoft/codepush/react/DownloadProgress.java
+++ b/android/app/src/main/java/com/microsoft/codepush/react/DownloadProgress.java
@@ -27,4 +27,8 @@ public WritableMap createWritableMap() {
     public boolean isCompleted() {
         return mTotalBytes == mReceivedBytes;
     }
+
+    long getReceivedBytes() {
+        return mReceivedBytes;
+    }
 }
diff --git a/android/app/src/main/java/com/microsoft/codepush/react/DownloadProgressEventDispatcher.java b/android/app/src/main/java/com/microsoft/codepush/react/DownloadProgressEventDispatcher.java
new file mode 100644
index 000000000..858191af9
--- /dev/null
+++ b/android/app/src/main/java/com/microsoft/codepush/react/DownloadProgressEventDispatcher.java
@@ -0,0 +1,23 @@
+package com.microsoft.codepush.react;
+
+class DownloadProgressEventDispatcher {
+    interface EventEmitter {
+        void emit(DownloadProgress downloadProgress);
+    }
+
+    private final EventEmitter mEventEmitter;
+    private long mLastDispatchedBytes = -1;
+
+    DownloadProgressEventDispatcher(EventEmitter eventEmitter) {
+        mEventEmitter = eventEmitter;
+    }
+
+    synchronized void dispatch(DownloadProgress downloadProgress) {
+        if (downloadProgress == null || downloadProgress.getReceivedBytes() <= mLastDispatchedBytes) {
+            return;
+        }
+
+        mEventEmitter.emit(downloadProgress);
+        mLastDispatchedBytes = downloadProgress.getReceivedBytes();
+    }
+}