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
Merged-In: I149b5926f20acd0e43c4071cc35520c6bc50efef
(cherry picked from commit ab21b8a838b40906cad5f9eafd020b7bde7ade1c)

2 files changed, 20 insertions, 6 deletions

diff --git a/packages/SettingsLib/src/com/android/settingslib/utils/ThreadUtils.java b/packages/SettingsLib/src/com/android/settingslib/utils/ThreadUtils.java
index 5c9a06f91e6a..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;
@@ -26,7 +27,7 @@ public class ThreadUtils {
 
     private static volatile Thread sMainThread;
     private static volatile Handler sMainThreadHandler;
-    private static volatile ExecutorService sSingleThreadExecutor;
+    private static volatile ExecutorService sThreadExecutor;
 
     /**
      * Returns true if the current thread is the UI thread.
@@ -64,10 +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 (sSingleThreadExecutor == null) {
-            sSingleThreadExecutor = Executors.newSingleThreadExecutor();
-        }
-        return sSingleThreadExecutor.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);
     }
 
     /**
@@ -77,4 +84,11 @@ public class ThreadUtils {
         getUiThreadHandler().post(runnable);
     }
 
+    private static synchronized ExecutorService getThreadExecutor() {
+        if (sThreadExecutor == null) {
+            sThreadExecutor = Executors.newFixedThreadPool(
+                    Runtime.getRuntime().availableProcessors());
+        }
+        return sThreadExecutor;
+    }
 }
diff --git a/packages/SettingsLib/tests/robotests/src/com/android/settingslib/utils/ThreadUtilsTest.java b/packages/SettingsLib/tests/robotests/src/com/android/settingslib/utils/ThreadUtilsTest.java
index 26db124c0041..5114b00d2711 100644
--- a/packages/SettingsLib/tests/robotests/src/com/android/settingslib/utils/ThreadUtilsTest.java
+++ b/packages/SettingsLib/tests/robotests/src/com/android/settingslib/utils/ThreadUtilsTest.java
@@ -50,7 +50,7 @@ public class ThreadUtilsTest {
     }
 
     @Test
-    public void testPostOnMainThread_shouldRunOnMainTread() {
+    public void testPostOnMainThread_shouldRunOnMainThread() {
         TestRunnable cr = new TestRunnable();
         ShadowLooper.pauseMainLooper();
         ThreadUtils.postOnMainThread(cr);