Merge "Start combining threads in system process."

core/java/com/android/internal/content/PackageMonitor.java

@@ -25,6 +25,7 @@ import android.os.Handler;
 import android.os.HandlerThread;
 import android.os.Looper;
 import android.os.UserHandle;
+import com.android.internal.os.BackgroundThread;
 
 import java.util.HashSet;
 
@@ -37,10 +38,6 @@ public abstract class PackageMonitor extends android.content.BroadcastReceiver {
     static final IntentFilter sNonDataFilt = new IntentFilter();
     static final IntentFilter sExternalFilt = new IntentFilter();
 
-    static final Object sLock = new Object();
-    static HandlerThread sBackgroundThread;
-    static Handler sBackgroundHandler;
-
     static {
         sPackageFilt.addAction(Intent.ACTION_PACKAGE_ADDED);
         sPackageFilt.addAction(Intent.ACTION_PACKAGE_REMOVED);
@@ -79,15 +76,7 @@ public abstract class PackageMonitor extends android.content.BroadcastReceiver {
         }
         mRegisteredContext = context;
         if (thread == null) {
-            synchronized (sLock) {
-                if (sBackgroundThread == null) {
-                    sBackgroundThread = new HandlerThread("PackageMonitor",
-                            android.os.Process.THREAD_PRIORITY_BACKGROUND);
-                    sBackgroundThread.start();
-                    sBackgroundHandler = new Handler(sBackgroundThread.getLooper());
-                }
-                mRegisteredHandler = sBackgroundHandler;
-            }
+            mRegisteredHandler = BackgroundThread.getHandler();
         } else {
             mRegisteredHandler = new Handler(thread);
         }

core/java/com/android/internal/os/BackgroundThread.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.internal.os;
+
+import android.os.Handler;
+import android.os.HandlerThread;
+
+/**
+ * Shared singleton background thread for each process.
+ */
+public final class BackgroundThread extends HandlerThread {
+    private static BackgroundThread sInstance;
+    private static Handler sHandler;
+
+    private BackgroundThread() {
+        super("android.bg", android.os.Process.THREAD_PRIORITY_BACKGROUND);
+    }
+
+    private static void ensureThreadLocked() {
+        if (sInstance == null) {
+            sInstance = new BackgroundThread();
+            sInstance.start();
+            sHandler = new Handler(sInstance.getLooper());
+        }
+    }
+
+    public static BackgroundThread get() {
+        synchronized (BackgroundThread.class) {
+            ensureThreadLocked();
+            return sInstance;
+        }
+    }
+
+    public static Handler getHandler() {
+        synchronized (BackgroundThread.class) {
+            ensureThreadLocked();
+            return sHandler;
+        }
+    }
+}