1 files changed, 112 insertions, 0 deletions
diff --git a/src/com/cyanogenmod/trebuchet/DeferredHandler.java b/src/com/cyanogenmod/trebuchet/DeferredHandler.java
new file mode 100644
index 000000000..48582f0ec
--- /dev/null
+++ b/src/com/cyanogenmod/trebuchet/DeferredHandler.java
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2008 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.cyanogenmod.trebuchet;
+
+import java.util.LinkedList;
+
+import android.os.Handler;
+import android.os.Looper;
+import android.os.Message;
+import android.os.MessageQueue;
+
+/**
+ * Queue of things to run on a looper thread.  Items posted with {@link #post} will not
+ * be actually enqued on the handler until after the last one has run, to keep from
+ * starving the thread.
+ *
+ * This class is fifo.
+ */
+public class DeferredHandler {
+    private LinkedList<Runnable> mQueue = new LinkedList<Runnable>();
+    private MessageQueue mMessageQueue = Looper.myQueue();
+    private Impl mHandler = new Impl();
+
+    private class Impl extends Handler implements MessageQueue.IdleHandler {
+        public void handleMessage(Message msg) {
+            Runnable r;
+            synchronized (mQueue) {
+                if (mQueue.size() == 0) {
+                    return;
+                }
+                r = mQueue.removeFirst();
+            }
+            r.run();
+            synchronized (mQueue) {
+                scheduleNextLocked();
+            }
+        }
+
+        public boolean queueIdle() {
+            handleMessage(null);
+            return false;
+        }
+    }
+
+    private class IdleRunnable implements Runnable {
+        Runnable mRunnable;
+
+        IdleRunnable(Runnable r) {
+            mRunnable = r;
+        }
+
+        public void run() {
+            mRunnable.run();
+        }
+    }
+
+    public DeferredHandler() {
+    }
+
+    /** Schedule runnable to run after everything that's on the queue right now. */
+    public void post(Runnable runnable) {
+        synchronized (mQueue) {
+            mQueue.add(runnable);
+            if (mQueue.size() == 1) {
+                scheduleNextLocked();
+            }
+        }
+    }
+
+    /** Schedule runnable to run when the queue goes idle. */
+    public void postIdle(final Runnable runnable) {
+        post(new IdleRunnable(runnable));
+    }
+
+    public void cancelRunnable(Runnable runnable) {
+        synchronized (mQueue) {
+            while (mQueue.remove(runnable)) { }
+        }
+    }
+
+    public void cancel() {
+        synchronized (mQueue) {
+            mQueue.clear();
+        }
+    }
+
+    void scheduleNextLocked() {
+        if (mQueue.size() > 0) {
+            Runnable peek = mQueue.getFirst();
+            if (peek instanceof IdleRunnable) {
+                mMessageQueue.addIdleHandler(mHandler);
+            } else {
+                mHandler.sendEmptyMessage(1);
+            }
+        }
+    }
+}
+