DroidFish: Added support for running the chess engine on a different computer, communicating with it using a network socket.

DroidFish/AndroidManifest.xml

@@ -7,6 +7,7 @@
     <supports-screens android:largeScreens="true"
                       android:anyDensity="true" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
+    <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.WAKE_LOCK" />
     <uses-permission android:name="android.permission.VIBRATE" />
     <uses-sdk android:minSdkVersion="3"

DroidFish/res/values/strings.xml

@@ -177,9 +177,12 @@ you are not actively using the program.\
     <string name="engine_error">Engine error</string>
     <string name="stockfish_engine">Stockfish</string>
     <string name="cuckoochess_engine">CuckooChess</string>
+    <string name="network_engine">Network Engine</string>
     <string name="failed_to_start_engine">Failed to start engine</string>
     <string name="engine_terminated">Engine terminated</string>
     <string name="uci_protocol_error">UCI protocol error</string>
+    <string name="network_host_syntax_error">Network host:port syntax error</string>
+    <string name="invalid_network_port">Invalid network port</string>
     <string name="start_new_game">Start New Game?</string>
     <string name="strength_cuckoo_hint">Use the CuckooChess engine for even lower strength.</string>
     <string name="err_too_few_spaces">Too few spaces</string>
@@ -223,6 +226,8 @@ you are not actively using the program.\
     <string name="prefs_threads_summary">Number of engine threads (CPU cores) to use. Not supported by all engines.</string>
     <string name="prefs_hash_title">Hash Table</string>
     <string name="prefs_hash_summary">Hash table size in megabytes</string>
+    <string name="prefs_networkEngine_title">Network engine</string>
+    <string name="prefs_networkEngine_summary">Enter host:port to connect to an engine on a computer on the network</string>
     <string name="prefs_time_control">Time Control</string>
     <string name="prefs_movesPerSession_title">Moves</string>
     <string name="prefs_movesPerSession_summary">Number of moves between time controls</string>

DroidFish/res/xml/preferences.xml

@@ -52,6 +52,12 @@
             android:entries="@array/engine_hash_texts"
             android:defaultValue="@string/engine_hash_default">
         </ListPreference>
+        <EditTextPreference
+            android:key="networkEngine"
+            android:title="@string/prefs_networkEngine_title"
+            android:summary="@string/prefs_networkEngine_summary"
+            android:defaultValue="">
+        </EditTextPreference>
         </PreferenceCategory>
     <PreferenceCategory
         android:title="@string/prefs_time_control">

DroidFish/src/org/petero/droidfish/DroidFish.java

@@ -150,6 +150,10 @@ public class DroidFish extends Activity implements GUIInterface {
     // FIXME!!! Handle PGN non-file intents with more than one game.
     // FIXME!!! File load/save of FEN data
 
+    // FIXME!!! Strength setting for external engines
+    // FIXME!!! Selection dialog for going into variation
+    // FIXME!!! Use two engines in engine/engine games
+
     private ChessBoard cb;
     private static DroidChessController ctrl = null;
     private boolean mShowThinking;
@@ -743,6 +747,7 @@ public class DroidFish extends Activity implements GUIInterface {
 
         String engine = settings.getString("engine", "stockfish");
         int strength = settings.getInt("strength", 1000);
+        engineOptions.networkEngine = settings.getString("networkEngine", "").trim();
         setEngineStrength(engine, strength);
 
         mPonderMode = settings.getBoolean("ponderMode", false);
@@ -787,8 +792,7 @@ public class DroidFish extends Activity implements GUIInterface {
         engineOptions.hintsEdit = settings.getBoolean("tbHintsEdit", false);
         engineOptions.rootProbe = settings.getBoolean("tbRootProbe", true);
         engineOptions.engineProbe = settings.getBoolean("tbEngineProbe", true);
-        String gtbPath = settings.getString("gtbPath", "");
+        String gtbPath = settings.getString("gtbPath", "").trim();
-        gtbPath = gtbPath.trim();
         if (gtbPath.length() == 0) {
             File extDir = Environment.getExternalStorageDirectory();
             String sep = File.separator;
@@ -897,6 +901,8 @@ public class DroidFish extends Activity implements GUIInterface {
             int idx = engine.lastIndexOf('/');
             String eName = engine.substring(idx + 1);
             engineTitleText.setText(eName);
+        } else if (engine.equals("networkEngine")) {
+            engineTitleText.setText(engineOptions.networkEngine);
         } else {
             String eName = getString(engine.equals("cuckoochess") ?
                                      R.string.cuckoochess_engine :
@@ -1676,7 +1682,8 @@ public class DroidFish extends Activity implements GUIInterface {
             String[] fileNames = findFilesInDirectory(engineDir, null);
             final int numFiles = fileNames.length;
             boolean haveSf = EngineUtil.internalStockFishName() != null;
-            final int nEngines = numFiles + (haveSf ? 2 : 1);
+            boolean haveNet = engineOptions.networkEngine.length() > 0;
+            final int nEngines = numFiles + 1 + (haveSf ? 1 : 0) + (haveNet ? 1 : 0);
             final String[] items = new String[nEngines];
             final String[] ids = new String[nEngines];
             int idx = 0;
@@ -1684,6 +1691,9 @@ public class DroidFish extends Activity implements GUIInterface {
                 ids[idx] = "stockfish"; items[idx] = getString(R.string.stockfish_engine); idx++;
             }
             ids[idx] = "cuckoochess"; items[idx] = getString(R.string.cuckoochess_engine); idx++;
+            if (haveNet) {
+                ids[idx] = "networkEngine"; items[idx] = getString(R.string.network_engine); idx++;
+            }
             String sep = File.separator;
             String base = Environment.getExternalStorageDirectory() + sep + engineDir + sep;
             for (int i = 0; i < numFiles; i++) {

DroidFish/src/org/petero/droidfish/EngineOptions.java

@@ -1,3 +1,21 @@
+/*
+    DroidFish - An Android chess program.
+    Copyright (C) 2012  Peter Österlund, peterosterlund2@gmail.com
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
 package org.petero.droidfish;
 
 /** Engine options, including endgame tablebase probing options. */
@@ -8,6 +26,7 @@ public final class EngineOptions {
     public boolean rootProbe;   // Only search optimal moves at root
     public boolean engineProbe; // Let engine use EGTB
     public String gtbPath;      // GTB directory path
+    public String networkEngine;// Host:port for network engine
 
     public EngineOptions() {
         hashMB = 16;
@@ -16,6 +35,7 @@ public final class EngineOptions {
         rootProbe = false;
         engineProbe = false;
         gtbPath = "";
+        networkEngine = "";
     }
 
     public EngineOptions(EngineOptions other) {
@@ -25,6 +45,7 @@ public final class EngineOptions {
         rootProbe = other.rootProbe;
         engineProbe = other.engineProbe;
         gtbPath = other.gtbPath;
+        networkEngine = other.networkEngine;
     }
 
     @Override
@@ -38,7 +59,8 @@ public final class EngineOptions {
                 (hintsEdit == other.hintsEdit) &&
                 (rootProbe == other.rootProbe) &&
                 (engineProbe == other.engineProbe) &&
-                gtbPath.equals(other.gtbPath));
+                gtbPath.equals(other.gtbPath) &&
+                networkEngine.equals(other.networkEngine));
     }
 
     @Override

DroidFish/src/org/petero/droidfish/engine/DroidComputerPlayer.java

@@ -602,7 +602,9 @@ public class DroidComputerPlayer {
         myAssert(searchRequest != null);
 
         engineName = "Computer";
-        uciEngine = UCIEngineBase.getEngine(context, searchRequest.engine, new UCIEngine.Report() {
+        uciEngine = UCIEngineBase.getEngine(context, searchRequest.engine,
+                                            engineOptions,
+                                            new UCIEngine.Report() {
             @Override
             public void reportError(String errMsg) {
                 if (errMsg == null)

DroidFish/src/org/petero/droidfish/engine/NetworkEngine.java

@@ -0,0 +1,255 @@
+/*
+    DroidFish - An Android chess program.
+    Copyright (C) 2012  Peter Österlund, peterosterlund2@gmail.com
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package org.petero.droidfish.engine;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.Socket;
+import java.net.UnknownHostException;
+
+import org.petero.droidfish.EngineOptions;
+import org.petero.droidfish.R;
+import android.content.Context;
+
+/** Engine running on a different computer. */
+public class NetworkEngine extends UCIEngineBase {
+    protected final Context context;
+    private final Report report;
+
+    private String networkEngine;
+    private Socket socket;
+    private Thread startupThread;
+    private Thread stdInThread;
+    private Thread stdOutThread;
+    private LocalPipe guiToEngine;
+    private LocalPipe engineToGui;
+    private boolean startedOk;
+    private boolean isRunning;
+    private boolean isError;
+
+    public NetworkEngine(Context context, String engine, EngineOptions engineOptions,
+                         Report report) {
+        this.context = context;
+        this.report = report;
+        this.networkEngine = engineOptions.networkEngine;
+        startupThread = null;
+        stdInThread = null;
+        guiToEngine = new LocalPipe();
+        engineToGui = new LocalPipe();
+        startedOk = false;
+        isRunning = false;
+        isError = false;
+    }
+
+    /** Create socket connection to remote server. */
+    private final synchronized void connect() {
+        if (socket == null) {
+            int idx = networkEngine.lastIndexOf(':');
+            if (idx < 0) {
+                isError = true;
+                report.reportError(context.getString(R.string.network_host_syntax_error));
+            } else {
+                try {
+                    String host = networkEngine.substring(0, idx);
+                    String port = networkEngine.substring(idx+1);
+                    int portNr = Integer.parseInt(port);
+                    socket = new Socket(host, portNr);
+                    socket.setTcpNoDelay(true);
+                } catch (UnknownHostException e) {
+                    isError = true;
+                    report.reportError(e.getMessage());
+                } catch (NumberFormatException nfe) {
+                    isError = true;
+                    report.reportError(context.getString(R.string.invalid_network_port));
+                } catch (IOException e) {
+                    isError = true;
+                    report.reportError(e.getMessage());
+                }
+            }
+            if (socket == null)
+                socket = new Socket();
+        }
+    }
+
+    /** @inheritDoc */
+    @Override
+    protected void startProcess() {
+        // Start thread to check for startup error
+        startupThread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                try {
+                    Thread.sleep(10000);
+                } catch (InterruptedException e) {
+                    return;
+                }
+                if (startedOk && isRunning && !isUCI) {
+                    isError = true;
+                    report.reportError(context.getString(R.string.uci_protocol_error));
+                }
+            }
+        });
+        startupThread.start();
+
+        // Start a thread to read data from engine
+        stdInThread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                connect();
+                try {
+                    InputStream is = socket.getInputStream();
+                    InputStreamReader isr = new InputStreamReader(is);
+                    BufferedReader br = new BufferedReader(isr, 8192);
+                    String line;
+                    boolean first = true;
+                    while ((line = br.readLine()) != null) {
+                        if (Thread.currentThread().isInterrupted())
+                            return;
+                        synchronized (engineToGui) {
+                            engineToGui.addLine(line);
+                            if (first) {
+                                startedOk = true;
+                                isRunning = true;
+                                first = false;
+                            }
+                        }
+                    }
+                } catch (IOException e) {
+                } finally {
+                    if (isRunning) {
+                        isError = true;
+                        isRunning = false;
+                        if (!startedOk)
+                            report.reportError(context.getString(R.string.failed_to_start_engine));
+                        else
+                            report.reportError(context.getString(R.string.engine_terminated));
+                    }
+                    try { socket.close(); } catch (IOException e) {}
+                }
+                engineToGui.close();
+            }
+        });
+        stdInThread.start();
+
+        // Start a thread to write data to engine
+        stdOutThread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                try {
+                    connect();
+                    String line;
+                    while ((line = guiToEngine.readLine()) != null) {
+                        if (Thread.currentThread().isInterrupted())
+                            return;
+                        line += "\n";
+                        socket.getOutputStream().write(line.getBytes());
+                    }
+                } catch (IOException e) {
+                    if (isRunning) {
+                        isError = true;
+                        report.reportError(e.getMessage());
+                    }
+                } finally {
+                    if (isRunning && !isError) {
+                        isError = true;
+                        report.reportError(context.getString(R.string.engine_terminated));
+                    }
+                    isRunning = false;
+                    try { socket.close(); } catch (IOException ex) {}
+                }
+            }
+        });
+        stdOutThread.start();
+    }
+
+    private int hashMB = -1;
+    private String gaviotaTbPath = "";
+    private boolean optionsInitialized = false;
+
+    /** @inheritDoc */
+    @Override
+    public void initOptions(EngineOptions engineOptions) {
+        super.initOptions(engineOptions);
+        hashMB = engineOptions.hashMB;
+        setOption("Hash", engineOptions.hashMB); 
+        if (engineOptions.engineProbe) {
+            gaviotaTbPath = engineOptions.gtbPath;
+            setOption("GaviotaTbPath", engineOptions.gtbPath);
+            setOption("GaviotaTbCache", 8);
+        }
+        optionsInitialized = true;
+    }
+
+    /** @inheritDoc */
+    @Override
+    public boolean optionsOk(EngineOptions engineOptions) {
+        if (isError)
+            return false;
+        if (!optionsInitialized)
+            return true;
+        if (!networkEngine.equals(engineOptions.networkEngine))
+            return false;
+        if (hashMB != engineOptions.hashMB)
+            return false;
+        if (haveOption("gaviotatbpath") && !gaviotaTbPath.equals(engineOptions.gtbPath))
+            return false;
+        return true;
+    }
+
+    /** @inheritDoc */
+    @Override
+    public void setStrength(int strength) {
+    }
+
+    /** @inheritDoc */
+    @Override
+    public String readLineFromEngine(int timeoutMillis) {
+        String ret = engineToGui.readLine(timeoutMillis);
+        if (ret == null)
+            return null;
+        if (ret.length() > 0) {
+//            System.out.printf("Engine -> GUI: %s\n", ret);
+        }
+        return ret;
+    }
+
+    /** @inheritDoc */
+    @Override
+    public void writeLineToEngine(String data) {
+//      System.out.printf("GUI -> Engine: %s\n", data);
+      guiToEngine.addLine(data);
+    }
+
+    /** @inheritDoc */
+    @Override
+    public void shutDown() {
+        isRunning = false;
+        if (startupThread != null)
+            startupThread.interrupt();
+        try { socket.getOutputStream().write("quit\n".getBytes()); } catch (IOException e) {}
+        try { socket.close(); } catch (IOException e) {}
+        super.shutDown();
+        if (stdOutThread != null)
+            stdOutThread.interrupt();
+        if (stdInThread != null)
+            stdInThread.interrupt();
+    }
+}

DroidFish/src/org/petero/droidfish/engine/UCIEngineBase.java

@@ -33,13 +33,16 @@ public abstract class UCIEngineBase implements UCIEngine {
     private HashMap<String, String> currOptions;
     protected boolean isUCI;
 
-    public static UCIEngine getEngine(Context context, String engine, Report report) {
+    public static UCIEngine getEngine(Context context, String engine,
+                                      EngineOptions engineOptions, Report report) {
         if ("stockfish".equals(engine) && (EngineUtil.internalStockFishName() == null))
             engine = "cuckoochess";
         if ("cuckoochess".equals(engine))
             return new CuckooChessEngine(report);
         else if ("stockfish".equals(engine))
             return new InternalStockFish(context, report);
+        else if ("networkEngine".equals(engine))
+            return new NetworkEngine(context, engine, engineOptions, report);
         else
             return new ExternalEngine(context, engine, report);
     }