/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Eclipse Public License, Version 1.0 (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.eclipse.org/org/documents/epl-v10.php
 *
 * 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.ide.eclipse.ndk.internal.launch;

import com.android.ddmlib.IDevice;
import com.android.ddmlib.IShellOutputReceiver;

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.atomic.AtomicBoolean;

/**
 * The {@link GdbServerTask} launches gdbserver on the given device and attaches it to
 * provided pid.
 */
public class GdbServerTask implements Runnable {
    private IDevice mDevice;
    private String mRunAs;
    private String mSocket;
    private int mPid;
    private CountDownLatch mAttachLatch;

    private GdbServerOutputReceiver mOutputReceiver;
    private Exception mLaunchException;

    private AtomicBoolean mCancelled = new AtomicBoolean(false);
    private AtomicBoolean mHasCompleted = new AtomicBoolean(false);

    /**
     * Construct a gdbserver task.
     * @param device device to run gdbserver on
     * @param runAsPackage name of the package in which gdbserver resides
     * @param socketName name of the local socket on which the server will listen
     * @param pid pid of task to attach to
     * @param attachLatch latch to notify when gdbserver gets attached to the task
     */
    public GdbServerTask(IDevice device, String runAsPackage, String socketName, int pid,
            CountDownLatch attachLatch) {
        mDevice = device;
        mRunAs = runAsPackage;
        mSocket = socketName;
        mPid = pid;
        mAttachLatch = attachLatch;

        mOutputReceiver = new GdbServerOutputReceiver();
    }

    /**
     * Runs gdbserver on the device and connects to the given task. If gdbserver manages to
     * successfully attach itself to the process, then it counts down on its attach latch.
     */
    @Override
    public void run() {
        // Launch gdbserver on the device.
        String command = String.format("run-as %s lib/gdbserver +%s --attach %d",
                mRunAs, mSocket, mPid);
        try {
            mDevice.executeShellCommand(command, mOutputReceiver, 0);
        } catch (Exception e) {
            mLaunchException = e;
        }
    }

    /** Returns any exceptions that might have occurred while launching gdbserver. */
    public Exception getLaunchException() {
        return mLaunchException;
    }

    /** Cancel gdbserver if it is running. */
    public void setCancelled() {
        mCancelled.set(true);
    }

    public String getShellOutput() {
        return mOutputReceiver.getOutput();
    }

    private class GdbServerOutputReceiver implements IShellOutputReceiver {
        private StringBuffer mOutput = new StringBuffer(100);

        @Override
        public synchronized void addOutput(byte[] data, int offset, int length) {
            mOutput.append(new String(data, offset, length));

            // notify other threads that gdbserver has attached to the task
            if (mOutput.toString().contains("Attached")) {
                mAttachLatch.countDown();
            }
        }

        @Override
        public void flush() {
            mHasCompleted.set(true);
        }

        @Override
        public boolean isCancelled() {
            return mCancelled.get();
        }

        public synchronized String getOutput() {
            return mOutput.toString();
        }
    }
}