Avoid opening games that have crashed.

On each open, increment a counter. And if we're able to close without a
crash intervening, decrement. Once we're trying to open with a non-0
counter we have a bad game. Open only after warning the user.

xwords4/android/app/src/main/java/org/eehouse/android/xw4/DBUtils.java

@@ -1106,9 +1106,11 @@ public class DBUtils {
 
     public static byte[] loadGame( Context context, GameLock lock )
     {
+        byte[] result = null;
         long rowid = lock.getRowid();
         Assert.assertTrue( ROWID_NOTFOUND != rowid );
-        byte[] result = getCached( rowid );
+        if ( Quarantine.safeToOpen( rowid ) ) {
+            result = getCached( rowid );
             if ( null == result ) {
                 String[] columns = { DBHelper.SNAPSHOT };
                 String selection = String.format( ROW_ID_FMT, rowid );
@@ -1125,6 +1127,7 @@ public class DBUtils {
                 }
                 setCached( rowid, result );
             }
+        }
         return result;
     }
 

xwords4/android/app/src/main/java/org/eehouse/android/xw4/DlgDelegate.java

@@ -53,6 +53,7 @@ public class DlgDelegate {
         SEND_EMAIL,
         WRITE_LOG_DB,
         CLEAR_LOG_DB,
+        CLEAR_QUARANTINE,
 
         // BoardDelegate
         UNDO_LAST_ACTION,

xwords4/android/app/src/main/java/org/eehouse/android/xw4/GamesListDelegate.java

@@ -1226,6 +1226,25 @@ public class GamesListDelegate extends ListDelegateBase
             } );
     }
 
+    private void openWithChecks( long rowid, GameSummary summary )
+    {
+        if ( ! m_launchedGames.contains( rowid ) ) {
+            if ( Quarantine.safeToOpen( rowid ) ) {
+                makeNotAgainBuilder( R.string.not_again_newselect,
+                                     R.string.key_notagain_newselect,
+                                     Action.OPEN_GAME )
+                    .setParams( rowid, summary )
+                    .show();
+            } else {
+                makeConfirmThenBuilder( R.string.unsafe_open_warning,
+                                        Action.CLEAR_QUARANTINE )
+                    .setPosButton( R.string.unsafe_open_disregard )
+                    .setParams( rowid, summary )
+                    .show();
+            }
+        }
+    }
+
     //////////////////////////////////////////////////////////////////////
     // SelectableItem interface
     //////////////////////////////////////////////////////////////////////
@@ -1237,13 +1256,7 @@ public class GamesListDelegate extends ListDelegateBase
         // an empty room name.
         if ( clicked instanceof GameListItem ) {
             long rowid = ((GameListItem)clicked).getRowID();
-            if ( ! m_launchedGames.contains( rowid ) ) {
+            openWithChecks( rowid, summary );
-                makeNotAgainBuilder( R.string.not_again_newselect,
-                                     R.string.key_notagain_newselect,
-                                     Action.OPEN_GAME )
-                    .setParams( rowid, summary )
-                    .show();
-            }
         }
     }
 
@@ -1344,6 +1357,13 @@ public class GamesListDelegate extends ListDelegateBase
         case OPEN_GAME:
             doOpenGame( params );
             break;
+        case CLEAR_QUARANTINE:
+            long rowid = (long)params[0];
+            Quarantine.clear( rowid );
+            GameSummary summary = (GameSummary)params[0];
+            openWithChecks( rowid, summary );
+            break;
+
         case CLEAR_SELS:
             clearSelections();
             break;

xwords4/android/app/src/main/java/org/eehouse/android/xw4/Quarantine.java

@@ -0,0 +1,143 @@
+/* -*- compile-command: "find-and-gradle.sh inXw4dDeb"; -*- */
+/*
+ * Copyright 2009-2020 by Eric House (xwords@eehouse.org).  All rights
+ * reserved.
+ *
+ * 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 2 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+package org.eehouse.android.xw4;
+
+import android.content.Context;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.io.Serializable;
+
+public class Quarantine {
+    private static final String TAG = Quarantine.class.getSimpleName();
+    private static final String DATA_KEY = TAG + "/key";
+
+    public static boolean safeToOpen( long rowid )
+    {
+        int count;
+        synchronized ( sDataRef ) {
+            count = get().getFor( rowid );
+        }
+        boolean result = count == 0; // Not too strict?
+        Log.d( TAG, "safeToOpen(%d) => %b (count=%d)", rowid, result, count );
+        return result;
+    }
+
+    public static void clear( long rowid )
+    {
+        synchronized ( sDataRef ) {
+            get().clear( rowid );
+            store();
+        }
+    }
+
+    public static void recordOpened( long rowid )
+    {
+        synchronized ( sDataRef ) {
+            get().increment( rowid );
+            store();
+            Log.d( TAG, "recordOpened(%d): %s", rowid, sDataRef[0].toString() );
+        }
+    }
+
+    public static void recordClosed( long rowid )
+    {
+        synchronized ( sDataRef ) {
+            get().decrement( rowid );
+            store();
+            Log.d( TAG, "recordClosed(%d): %s", rowid, sDataRef[0].toString() );
+        }
+    }
+
+    private static class Data implements Serializable {
+        private HashMap<Long, Integer> mCounts = new HashMap<>();
+
+        synchronized void increment( long rowid ) {
+            if ( ! mCounts.containsKey(rowid) ) {
+                mCounts.put(rowid, 0);
+            }
+            mCounts.put( rowid, mCounts.get(rowid) + 1 );
+        }
+
+        synchronized void decrement( long rowid )
+        {
+            Assert.assertTrue( mCounts.containsKey(rowid) );
+            mCounts.put( rowid, mCounts.get(rowid) - 1 );
+            Assert.assertTrueNR( mCounts.get(rowid) >= 0 );
+        }
+
+        synchronized int getFor( long rowid )
+        {
+            int result = mCounts.containsKey(rowid) ? mCounts.get( rowid ) : 0;
+            return result;
+        }
+
+        synchronized void clear( long rowid )
+        {
+            mCounts.put( rowid, 0 );
+        }
+
+        @Override
+        synchronized public String toString()
+        {
+            StringBuilder sb = new StringBuilder().append("[");
+            synchronized ( mCounts ) {
+                for ( long rowid : mCounts.keySet() ) {
+                    int count = mCounts.get(rowid);
+                    sb.append( String.format("{%d: %d}", rowid, count ) );
+                }
+            }
+            return sb.append("]").toString();
+        }
+    }
+
+    private static Data[] sDataRef = {null};
+    
+    private static void store()
+    {
+        synchronized( sDataRef ) {
+            DBUtils.setSerializableFor( getContext(), DATA_KEY, sDataRef[0] );
+        }
+    }
+
+    private static Data get()
+    {
+        Data data;
+        synchronized ( sDataRef ) {
+            data = sDataRef[0];
+            if ( null == data ) {
+                data = (Data)DBUtils.getSerializableFor( getContext(), DATA_KEY );
+                if ( null == data ) {
+                    data = new Data();
+                } else {
+                    Log.d( TAG, "loading existing: %s", data );
+                }
+                sDataRef[0] = data;
+            }
+        }
+        return data;
+    }
+
+    private static Context getContext()
+    {
+        return XWApp.getContext();
+    }
+}

xwords4/android/app/src/main/java/org/eehouse/android/xw4/jni/XwJNI.java

@@ -28,6 +28,7 @@ import org.eehouse.android.xw4.Assert;
 import org.eehouse.android.xw4.BuildConfig;
 import org.eehouse.android.xw4.Log;
 import org.eehouse.android.xw4.NetLaunchInfo;
+import org.eehouse.android.xw4.Quarantine;
 import org.eehouse.android.xw4.Utils;
 import org.eehouse.android.xw4.jni.CommsAddrRec.CommsConnType;
 
@@ -46,6 +47,7 @@ public class XwJNI {
             m_ptrGame = ptr;
             m_rowid = rowid;
             mStack = android.util.Log.getStackTraceString(new Exception());
+            Quarantine.recordOpened( rowid );
         }
 
         public synchronized long ptr()
@@ -73,6 +75,7 @@ public class XwJNI {
             //        getClass().getName(), this, m_rowid, m_refCount );
             if ( 0 == m_refCount ) {
                 if ( 0 != m_ptrGame ) {
+                    Quarantine.recordClosed( m_rowid );
                     if ( haveEnv( getJNI().m_ptrGlobals ) ) {
                         game_dispose( this ); // will crash if haveEnv fails
                     } else {

xwords4/android/app/src/main/res/values/strings.xml

@@ -2520,6 +2520,11 @@
     <string name="history_msg_fmt"> Message: %1$s.</string>
     <string name="history_autopause">Auto-paused.</string>
 
+    <string name="unsafe_open_warning">This game has caused CrossWords
+    to crash recently and is likely corrupt. Do you want to open it
+    anyway?</string>
+    <string name="unsafe_open_disregard">Open anyway</string>
+
     <string name="gamel_menu_logs">Debug logs</string>
     <!-- Debug-build-only menu to turn on saving of logs -->
     <string name="gamel_menu_logstore_on">Enable log storage</string>