From ab21b8a838b40906cad5f9eafd020b7bde7ade1c Mon Sep 17 00:00:00 2001
From: Jason Chiu <chiujason@google.com>
Date: Tue, 29 Oct 2019 17:06:28 +0800
Subject: [PATCH] Fix Settings creating too many threads unexpectedly

Provide a method to submit a Callable for execution in the shared
background thread pool.

Bug: 143434413
Test: manual, robotest
Change-Id: I149b5926f20acd0e43c4071cc35520c6bc50efef
---
 .../com/android/settingslib/utils/ThreadUtils.java | 23 +++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/packages/SettingsLib/src/com/android/settingslib/utils/ThreadUtils.java b/packages/SettingsLib/src/com/android/settingslib/utils/ThreadUtils.java
index 4e052f1aeca4..69f1c17f97b1 100644
--- a/packages/SettingsLib/src/com/android/settingslib/utils/ThreadUtils.java
+++ b/packages/SettingsLib/src/com/android/settingslib/utils/ThreadUtils.java
@@ -18,6 +18,7 @@ package com.android.settingslib.utils;
 import android.os.Handler;
 import android.os.Looper;
 
+import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
@@ -64,11 +65,16 @@ public class ThreadUtils {
      * @Return A future of the task that can be monitored for updates or cancelled.
      */
     public static Future postOnBackgroundThread(Runnable runnable) {
-        if (sThreadExecutor == null) {
-            sThreadExecutor = Executors.newFixedThreadPool(
-                    Runtime.getRuntime().availableProcessors());
-        }
-        return sThreadExecutor.submit(runnable);
+        return getThreadExecutor().submit(runnable);
+    }
+
+    /**
+     * Posts callable in background using shared background thread pool.
+     *
+     * @Return A future of the task that can be monitored for updates or cancelled.
+     */
+    public static Future postOnBackgroundThread(Callable callable) {
+        return getThreadExecutor().submit(callable);
     }
 
     /**
@@ -78,4 +84,11 @@ public class ThreadUtils {
         getUiThreadHandler().post(runnable);
     }
 
+    private static synchronized ExecutorService getThreadExecutor() {
+        if (sThreadExecutor == null) {
+            sThreadExecutor = Executors.newFixedThreadPool(
+                    Runtime.getRuntime().availableProcessors());
+        }
+        return sThreadExecutor;
+    }
 }
-- 
2.11.0