Make the record formats report decoding errors through the page curso…

…r setCursorError mechanism.

community/io/src/main/java/org/neo4j/io/pagecache/PageCursor.java

@@ -299,7 +299,8 @@ public abstract class PageCursor implements AutoCloseable
     public abstract boolean checkAndClearBoundsFlag();
 
     /**
-     * Check if a cursor error has been set, and if so, remove it from the cursor and throw it.
+     * Check if a cursor error has been set on this or any linked cursor, and if so, remove it from the cursor
+     * and throw it as a {@link CursorException}.
      */
     public abstract void checkAndClearCursorError() throws CursorException;
 
@@ -321,6 +322,12 @@ public abstract class PageCursor implements AutoCloseable
      */
     public abstract void setCursorError( String message );
 
+    /**
+     * Unconditionally clear any error condition that has been set on this or any linked cursor, without throwing an
+     * exception.
+     */
+    public abstract void clearCursorError();
+
     /**
      * Open a new page cursor with the same pf_flags as this cursor, as if calling the {@link PagedFile#io(long, int)}
      * on the relevant paged file. This cursor will then also delegate to the linked cursor when checking

community/io/src/main/java/org/neo4j/io/pagecache/impl/CompositePageCursor.java

@@ -470,6 +470,13 @@ public void setCursorError( String message )
         cursor( 0 ).setCursorError( message );
     }
 
+    @Override
+    public void clearCursorError()
+    {
+        first.clearCursorError();
+        second.clearCursorError();
+    }
+
     @Override
     public PageCursor openLinkedCursor( long pageId )
     {

community/io/src/main/java/org/neo4j/io/pagecache/impl/DelegatingPageCursor.java

@@ -155,6 +155,12 @@ public void setCursorError( String message )
         delegate.setCursorError( message );
     }
 
+    @Override
+    public void clearCursorError()
+    {
+        delegate.clearCursorError();
+    }
+
     @Override
     public PageCursor openLinkedCursor( long pageId )
     {

community/io/src/main/java/org/neo4j/io/pagecache/impl/muninn/CursorExceptionWithPreciseStackTrace.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2002-2016 "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.io.pagecache.impl.muninn;
+
+import org.neo4j.io.pagecache.CursorException;
+
+/**
+ * This exception is used to indicate in the stack trace, whether or not
+ * {@link MuninnPageCursor#usePreciseCursorErrorStackTraces} is enabled.
+ *
+ * This is useful because it allows us to clearly see how much we can trust the stack traces for decoding errors.
+ */
+final class CursorExceptionWithPreciseStackTrace extends CursorException
+{
+    public CursorExceptionWithPreciseStackTrace( String message )
+    {
+        super( message );
+    }
+}

community/io/src/main/java/org/neo4j/io/pagecache/impl/muninn/MuninnPageCursor.java

@@ -21,6 +21,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.util.Objects;
 
 import org.neo4j.concurrent.BinaryLatch;
 import org.neo4j.io.pagecache.CursorException;
@@ -38,6 +39,9 @@ abstract class MuninnPageCursor extends PageCursor
     private static final boolean tracePinnedCachePageId =
             flag( MuninnPageCursor.class, "tracePinnedCachePageId", false );
 
+    private static final boolean usePreciseCursorErrorStackTraces =
+            flag( MuninnPageCursor.class, "usePreciseCursorErrorStackTraces", true );
+
     // Size of the respective primitive types in bytes.
     private static final int SIZE_OF_BYTE = Byte.BYTES;
     private static final int SIZE_OF_SHORT = Short.BYTES;
@@ -60,7 +64,10 @@ abstract class MuninnPageCursor extends PageCursor
     private int filePageSize;
     private int offset;
     private boolean outOfBounds;
-    private String cursorExceptionMessage;
+    // This is a String with the exception message if usePreciseCursorErrorStackTraces is false, otherwise it is a
+    // CursorExceptionWithPreciseStackTrace with the message and stack trace pointing more or less directly at the
+    // offending code.
+    private Object cursorException;
 
     MuninnPageCursor( long victimPage )
     {
@@ -104,7 +111,7 @@ public final void reset( MuninnPage page )
     @Override
     public final boolean next( long pageId ) throws IOException
     {
-        if ( currentPageId == nextPageId )
+        if ( currentPageId == pageId )
         {
             return true;
         }
@@ -166,7 +173,7 @@ void clearPageState()
         pageSize = 0; // make all future bound checks fail
         page = null; // make all future page navigation fail
         currentPageId = UNBOUND_PAGE_ID;
-        cursorExceptionMessage = null;
+        cursorException = null;
     }
 
     @Override
@@ -708,18 +715,26 @@ public void checkAndClearCursorError() throws CursorException
         MuninnPageCursor cursor = this;
         do
         {
-            String message = cursor.cursorExceptionMessage;
-            if ( message != null )
+            Object error = cursor.cursorException;
+            if ( error != null )
             {
                 clearCursorError( cursor );
-                throw new CursorException( message );
+                if ( usePreciseCursorErrorStackTraces )
+                {
+                    throw (CursorExceptionWithPreciseStackTrace) error;
+                }
+                else
+                {
+                    throw new CursorException( (String) error );
+                }
             }
             cursor = cursor.linkedCursor;
         }
         while ( cursor != null );
     }
 
-    protected void clearCursorError()
+    @Override
+    public void clearCursorError()
     {
         clearCursorError( this );
     }
@@ -728,7 +743,7 @@ private void clearCursorError( MuninnPageCursor cursor )
     {
         while ( cursor != null )
         {
-            cursor.cursorExceptionMessage = null;
+            cursor.cursorException = null;
             cursor = cursor.linkedCursor;
         }
     }
@@ -742,6 +757,14 @@ public void raiseOutOfBounds()
     @Override
     public void setCursorError( String message )
     {
-        this.cursorExceptionMessage = message;
+        Objects.requireNonNull( message );
+        if ( usePreciseCursorErrorStackTraces )
+        {
+            this.cursorException = new CursorExceptionWithPreciseStackTrace( message );
+        }
+        else
+        {
+            this.cursorException = message;
+        }
     }
 }

community/io/src/test/java/org/neo4j/adversaries/pagecache/AdversarialReadPageCursor.java

@@ -371,20 +371,26 @@ public boolean shouldRetry() throws IOException
                 IllegalStateException.class );
         if ( state.hasPreparedInconsistentRead() )
         {
-            delegate.shouldRetry();
-            delegate.setOffset( 0 );
+            resetDelegate();
             return true;
         }
         if ( state.hasInconsistentRead() )
         {
-            delegate.shouldRetry();
-            delegate.setOffset( 0 );
+            resetDelegate();
             return true;
         }
         boolean retry = delegate.shouldRetry();
         return retry || (linkedCursor != null && linkedCursor.shouldRetry());
     }
 
+    private void resetDelegate() throws IOException
+    {
+        delegate.shouldRetry();
+        delegate.setOffset( 0 );
+        delegate.checkAndClearBoundsFlag();
+        delegate.clearCursorError();
+    }
+
     @Override
     public int copyTo( int sourceOffset, PageCursor targetCursor, int targetOffset, int lengthInBytes )
     {
@@ -424,6 +430,12 @@ public void setCursorError( String message )
         delegate.setCursorError( message );
     }
 
+    @Override
+    public void clearCursorError()
+    {
+        delegate.clearCursorError();
+    }
+
     @Override
     public PageCursor openLinkedCursor( long pageId )
     {

community/io/src/test/java/org/neo4j/adversaries/pagecache/AdversarialWritePageCursor.java

@@ -291,6 +291,12 @@ public void setCursorError( String message )
         delegate.setCursorError( message );
     }
 
+    @Override
+    public void clearCursorError()
+    {
+        delegate.clearCursorError();
+    }
+
     @Override
     public PageCursor openLinkedCursor( long pageId )
     {