1 files changed, 72 insertions, 0 deletions
diff --git a/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/GeckoBackgroundThread.java b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/GeckoBackgroundThread.java
new file mode 100644
index 0000000000..01b177fe21
--- /dev/null
+++ b/mobile/android/geckoview/src/main/java/org/mozilla/gecko/util/GeckoBackgroundThread.java
@@ -0,0 +1,72 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.util;
+
+import android.os.Handler;
+import android.os.Looper;
+
+final class GeckoBackgroundThread extends Thread {
+  private static final String LOOPER_NAME = "GeckoBackgroundThread";
+
+  // Guarded by 'GeckoBackgroundThread.class'.
+  private static Handler handler;
+  private static Thread thread;
+
+  // The initial Runnable to run on the new thread. Its purpose
+  // is to avoid us having to wait for the new thread to start.
+  private Runnable mInitialRunnable;
+
+  // Singleton, so private constructor.
+  private GeckoBackgroundThread(final Runnable initialRunnable) {
+    mInitialRunnable = initialRunnable;
+  }
+
+  @Override
+  public void run() {
+    setName(LOOPER_NAME);
+    Looper.prepare();
+
+    synchronized (GeckoBackgroundThread.class) {
+      handler = new Handler();
+      GeckoBackgroundThread.class.notifyAll();
+    }
+
+    if (mInitialRunnable != null) {
+      mInitialRunnable.run();
+      mInitialRunnable = null;
+    }
+
+    Looper.loop();
+  }
+
+  private static void startThread(final Runnable initialRunnable) {
+    thread = new GeckoBackgroundThread(initialRunnable);
+    thread.setDaemon(true);
+    thread.start();
+  }
+
+  // Get a Handler for a looper thread, or create one if it doesn't yet exist.
+  /*package*/ static synchronized Handler getHandler() {
+    if (thread == null) {
+      startThread(null);
+    }
+
+    while (handler == null) {
+      try {
+        GeckoBackgroundThread.class.wait();
+      } catch (final InterruptedException e) {
+      }
+    }
+    return handler;
+  }
+
+  /*package*/ static synchronized void post(final Runnable runnable) {
+    if (thread == null) {
+      startThread(runnable);
+      return;
+    }
+    getHandler().post(runnable);
+  }
+}