1 files changed, 143 insertions, 0 deletions
diff --git a/src/com/android/stk/WatchDog.java b/src/com/android/stk/WatchDog.java
new file mode 100644
index 0000000..423e694
--- /dev/null
+++ b/src/com/android/stk/WatchDog.java
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2007 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.stk;
+
+import android.os.Handler;
+import android.util.Log;
+
+/**
+ * This interface defines Event to be used by WatchDog.
+ * Watchdog expires when event is set.
+ */
+interface Event {
+
+    public void set();
+    
+    public void unSet();
+
+    public boolean isSet();
+}
+
+/**
+ * This class implements Watch Dog using a daemon thread.
+ * WatchDog waits for an event to expire and execute Runnable in the caller 
+ * context.
+ */
+class WatchDog extends Thread {
+    // Constants
+    private static final int POLLING_INTERVAL = 150;
+    public static final int TIMEOUT_WAIT_FOREVER = Integer.MAX_VALUE;
+
+    private static final String TAG = "WatchDog";
+    private static final boolean DBG = true;
+
+    // Members
+    private Event mEvent = null;  
+    private Handler mCaller = null;
+    private Runnable mRunnable = null;
+    private int mTimeout = TIMEOUT_WAIT_FOREVER;
+    private int mInterval = POLLING_INTERVAL;
+    private int mElapsedTime = 0;
+    private Object mElapsedTimeLock = new Object();
+    private boolean mCanceled = false;
+    private boolean mPaused = false; 
+
+    class VoidEvent implements Event {
+        public void set() {}
+        
+        public void unSet() {}
+
+        public boolean isSet() {
+            return false;
+        }
+    }
+
+    WatchDog(Event event, Handler caller, Runnable onEventResponse, int timeout) {
+        mEvent = event == null ? new VoidEvent() : event;
+        mCaller = caller;
+        mRunnable = onEventResponse;
+        mTimeout = timeout;
+
+        this.setDaemon(true);
+        this.start();
+    }
+
+    public void cancel() {
+        mTimeout = 0;
+        mCanceled = true;
+    }
+
+    public void reset() {
+        synchronized (mElapsedTimeLock) {
+            mElapsedTime = 0;
+        }
+    }
+    
+    public void pause() {
+        mPaused = true;
+    }
+    
+    public void unpause() {
+        mPaused = false;
+    }
+
+    @Override
+    public void run() {
+        watchEvent();
+        // When event expires post response to caller.
+        if (mCaller != null && mRunnable != null) {
+            if (!mCanceled) {
+                mCaller.post(mRunnable);
+            }
+        }
+    }
+
+    // Synchronized method, block until event expires.
+    private void watchEvent() {
+        while (!isEventSet() && !isTimedOut()) {
+            try {
+                Thread.sleep(mInterval);
+                incrementTime();
+            } catch (InterruptedException ie) {
+                if (DBG) Log.d(TAG, ie.toString());
+            }
+        }
+    }
+
+    private void incrementTime() {
+        if (mPaused) {
+            return;
+        }
+        synchronized (mElapsedTimeLock) {
+            mElapsedTime += (mTimeout == TIMEOUT_WAIT_FOREVER ? 0 : mInterval);
+        }
+    }
+
+    private boolean isTimedOut() {
+        if (mPaused) {
+            return false;
+        }
+        return (mElapsedTime >= mTimeout);
+    }
+
+    private boolean isEventSet() {
+        if (mPaused) {
+            return false;
+        }
+        return mEvent.isSet();
+    }
+}