android/sdremote/mobile/src/main/java/org/libreoffice/impressremote/communication/CommandsTransmitter.java

/* -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
 * This file is part of the LibreOffice project.
 *
 * 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.libreoffice.impressremote.communication;

import android.os.AsyncTask;
import android.util.Log;

import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;

public class CommandsTransmitter {
    private final BufferedWriter mCommandsWriter;

    public CommandsTransmitter(ServerConnection aServerConnection) {
        mCommandsWriter = buildCommandsWriter(aServerConnection);
    }

    private BufferedWriter buildCommandsWriter(ServerConnection aServerConnection) {
        try {
            OutputStream aCommandsStream = aServerConnection.buildCommandsStream();

            return new BufferedWriter(
                new OutputStreamWriter(aCommandsStream, Protocol.CHARSET));
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("Unable to create commands writer:" + e.getMessage());
        }
    }

    public void pair(String aDeviceName, String aPin) {
        writeCommand(Protocol.Commands
            .prepareCommand(Protocol.Commands.PAIR_WITH_SERVER, aDeviceName,
                aPin));
    }

    private void writeCommand(final String aCommand) {
        // TODO: We should ensure that all communication happens on one Thread. By default AsyncTask
        // executes on a thread pool (at least on modern devices). See tdf#111398
        new WriteCommandTask(mCommandsWriter).execute(aCommand);
    }

    public void performNextTransition() {
        writeCommand(Protocol.Commands
            .prepareCommand(Protocol.Commands.TRANSITION_NEXT));
    }

    public void performPreviousTransition() {
        writeCommand(Protocol.Commands
            .prepareCommand(Protocol.Commands.TRANSITION_PREVIOUS));
    }

    public void setCurrentSlide(int slideIndex) {
        writeCommand(Protocol.Commands
            .prepareCommand(Protocol.Commands.GO_TO_SLIDE,
                Integer.toString(slideIndex)));
    }

    public void setUpBlankScreen() {
        writeCommand(Protocol.Commands
            .prepareCommand(Protocol.Commands.PRESENTATION_BLANK_SCREEN));
    }

    public void resumePresentation() {
        writeCommand(Protocol.Commands
            .prepareCommand(Protocol.Commands.PRESENTATION_RESUME));
    }

    public void startPresentation() {
        writeCommand(Protocol.Commands
            .prepareCommand(Protocol.Commands.PRESENTATION_START));
    }

    public void stopPresentation() {
        writeCommand(Protocol.Commands
            .prepareCommand(Protocol.Commands.PRESENTATION_STOP));
    }

    public void startPointer(float x, float y) {
        writeCommand(Protocol.Commands
            .prepareCommand(Protocol.Commands.POINTER_STARTED,
                            Float.toString(x), Float.toString(y)));
    }

    public void movePointer(float x, float y) {
        writeCommand(Protocol.Commands
            .prepareCommand(Protocol.Commands.POINTER_COORDINATION,
                            Float.toString(x), Float.toString(y)));
    }

    public void stopPointer() {
        writeCommand(Protocol.Commands
            .prepareCommand(Protocol.Commands.POINTER_DISMISSED));
    }

    // non-static AsyncTask can leak memory
    private static class WriteCommandTask extends AsyncTask<String, Void, Void> {
        private final BufferedWriter mCommandsWriter;

        public WriteCommandTask(BufferedWriter writer) {
            mCommandsWriter = writer;
        }

        @Override
        protected Void doInBackground(String... commands) {
            try {
                mCommandsWriter.write(commands[0]);
                mCommandsWriter.flush();
            } catch (IOException e) {
                Log.e("CommandsTransmitter", "Unable to write command:" + e.getMessage());
            }
            return null;
        }
    }
}

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