NeoStoreUtil access doesn't read trailer as record by mistake

community/kernel/src/main/java/org/neo4j/kernel/impl/store/record/NeoStoreUtil.java

@@ -32,10 +32,14 @@
 import org.neo4j.kernel.impl.store.NeoStore.Position;
 import org.neo4j.kernel.impl.store.StoreId;
 import org.neo4j.kernel.impl.storemigration.StoreFileType;
+import org.neo4j.kernel.impl.storemigration.StoreVersionCheck;
+import org.neo4j.kernel.impl.storemigration.StoreVersionCheck.Result;
 
 import static java.lang.String.format;
 
+import static org.neo4j.helpers.UTF8.encode;
 import static org.neo4j.kernel.impl.store.NeoStore.RECORD_SIZE;
+import static org.neo4j.kernel.impl.store.NeoStore.TYPE_DESCRIPTOR;
 
 /**
  * Reads the contents of a {@link NeoStore neostore} store. Namely all of its {@link Position records}
@@ -67,9 +71,19 @@ public NeoStoreUtil( File storeDir )
 
     public NeoStoreUtil( File storeDir, FileSystemAbstraction fs )
     {
-        try ( StoreChannel channel = fs.open( neoStoreFile( storeDir, StoreFileType.STORE ), "r" ) )
+        File neoStoreFile = neoStoreFile( storeDir, StoreFileType.STORE );
+        String currentTypeDescriptorAndVersion = NeoStore.buildTypeDescriptorAndVersion( TYPE_DESCRIPTOR );
+        boolean storeHasTrailer = hasTrailer( neoStoreFile, fs, currentTypeDescriptorAndVersion );
+        try ( StoreChannel channel = fs.open( neoStoreFile, "r" ) )
         {
-            ByteBuffer buf = ByteBuffer.allocate( Position.values().length * RECORD_SIZE );
+            int contentSize = (int) channel.size();
+            if ( storeHasTrailer )
+            {
+                int trailerSize = encode( currentTypeDescriptorAndVersion ).length;
+                contentSize -= trailerSize;
+            }
+            int records = contentSize/RECORD_SIZE;
+            ByteBuffer buf = ByteBuffer.allocate( records * RECORD_SIZE );
             channel.read( buf );
             buf.flip();
 
@@ -84,6 +98,13 @@ public NeoStoreUtil( File storeDir, FileSystemAbstraction fs )
         }
     }
 
+    private boolean hasTrailer( File neoStoreFile, FileSystemAbstraction fs, String currentTypeDescriptorAndVersion )
+    {
+        StoreVersionCheck trailerCheck = new StoreVersionCheck( fs );
+        Result result = trailerCheck.hasVersion( neoStoreFile, currentTypeDescriptorAndVersion );
+        return result.outcome == Result.Outcome.ok || result.outcome == Result.Outcome.unexpectedUpgradingStoreVersion;
+    }
+
     private long nextRecord( ByteBuffer buf )
     {
         buf.get(); // in use byte

community/kernel/src/test/java/org/neo4j/kernel/impl/store/record/NeoStoreUtilTest.java

@@ -0,0 +1,119 @@
+/**
+ * Copyright (c) 2002-2015 "Neo Technology,"
+ * Network Engine for Objects in Lund AB [http://neotechnology.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * Neo4j 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.neo4j.kernel.impl.store.record;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+import org.junit.Rule;
+import org.junit.Test;
+
+import org.neo4j.io.fs.FileSystemAbstraction;
+import org.neo4j.io.fs.StoreChannel;
+import org.neo4j.kernel.impl.store.NeoStore;
+import org.neo4j.kernel.impl.store.NeoStore.Position;
+import org.neo4j.test.EphemeralFileSystemRule;
+
+import static java.nio.ByteBuffer.wrap;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
+
+import static org.neo4j.helpers.UTF8.encode;
+import static org.neo4j.kernel.impl.store.NeoStore.TYPE_DESCRIPTOR;
+
+public class NeoStoreUtilTest
+{
+    @Test
+    public void shouldNotReadTrailerAsRecordData() throws Exception
+    {
+        // GIVEN
+        long[] values = new long[] {1, 2, 3, 4, 5};
+        NeoStoreUtil access = new NeoStoreUtil( neoStoreFile( fs.get(), true, values ), fs.get() );
+
+        // WHEN
+        for ( int i = 0; i < values.length; i++ )
+        {
+            assertEquals( values[i], access.getValue( Position.values()[i] ) );
+        }
+
+        // THEN
+        try
+        {
+            access.getValue( Position.values()[values.length] );
+            fail( "Shouldn't have read more records" );
+        }
+        catch ( IllegalStateException e )
+        {   // OK
+        }
+    }
+
+    @Test
+    public void shouldReadAllRecordsEvenOnStoreWithoutTrailer() throws Exception
+    {
+        // GIVEN
+        long[] values = new long[] {1, 2, 3, 4, 5};
+        NeoStoreUtil access = new NeoStoreUtil( neoStoreFile( fs.get(), false, values ), fs.get() );
+
+        // WHEN
+        for ( int i = 0; i < values.length; i++ )
+        {
+            assertEquals( values[i], access.getValue( Position.values()[i] ) );
+        }
+
+        // THEN
+        try
+        {
+            access.getValue( Position.values()[values.length] );
+            fail( "Shouldn't have read more records" );
+        }
+        catch ( IllegalStateException e )
+        {   // OK
+        }
+    }
+
+    private File neoStoreFile( FileSystemAbstraction fs, boolean addVersionTrailer, long... recordValues )
+            throws IOException
+    {
+        File dir = new File( "dir" );
+        fs.mkdirs( dir );
+        try ( StoreChannel channel = fs.create( new File( dir, NeoStore.DEFAULT_NAME ) ) )
+        {
+            ByteBuffer buffer = ByteBuffer.allocate( NeoStore.RECORD_SIZE );
+            for ( long recordValue : recordValues )
+            {
+                buffer.clear();
+                buffer.put( Record.IN_USE.byteValue() );
+                buffer.putLong( recordValue );
+                buffer.flip();
+                channel.write( buffer );
+            }
+
+            if ( addVersionTrailer )
+            {
+                channel.write( wrap( encode( NeoStore.buildTypeDescriptorAndVersion( TYPE_DESCRIPTOR ) ) ) );
+            }
+        }
+        return dir;
+    }
+
+    public final @Rule EphemeralFileSystemRule fs = new EphemeralFileSystemRule();
+}

community/kernel/src/test/java/org/neo4j/kernel/impl/storemigration/MigrationTestUtils.java

@@ -86,6 +86,9 @@ public static void changeVersionNumber( FileSystemAbstraction fileSystem, File s
         fileChannel.close();
     }
 
+    /**
+     * Removes the version trailer from the store files.
+     */
     public static void truncateFile( FileSystemAbstraction fileSystem, File storeFile,
             String suffixToDetermineTruncationLength ) throws IOException
     {