Introduced adversarial page cache

Such page cache implementation is able to wrap the given page cache and
introduce some misbehaviour to exercise the user code. It can either throw
RuntimeExceptions/IOExceptions or return a page cursor with inconsistent
reads. Misbehaviour is controlled by the given Adversary.

Changed PageCacheRule to use the AdversarialPageCache.

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

@@ -279,9 +279,8 @@ public interface PageCursor extends AutoCloseable
      * an equivalent io() call. In other words, the next call to next() will
      * move the cursor to the starting page that was specified in the io() that
      * produced the cursor.
-     * @throws IOException
      */
-    void rewind() throws IOException;
+    void rewind();
 
     /**
      * Moves the cursor to the next page, if any, and returns true when it is

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

@@ -0,0 +1,83 @@
+/*
+ * 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.adversaries.pagecache;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.Objects;
+
+import org.neo4j.adversaries.Adversary;
+import org.neo4j.io.pagecache.PageCache;
+import org.neo4j.io.pagecache.PagedFile;
+
+/**
+ * A {@linkplain PageCache page cache} that wraps another page cache and an {@linkplain Adversary adversary} to provide
+ * a misbehaving page cache implementation for testing.
+ * <p>
+ * Depending on the adversary each operation can throw either {@link RuntimeException} like {@link SecurityException}
+ * or {@link IOException} like {@link FileNotFoundException}.
+ */
+@SuppressWarnings( "unchecked" )
+public class AdversarialPageCache implements PageCache
+{
+    private final PageCache delegate;
+    private final Adversary adversary;
+
+    public AdversarialPageCache( PageCache delegate, Adversary adversary )
+    {
+        this.delegate = Objects.requireNonNull( delegate );
+        this.adversary = Objects.requireNonNull( adversary );
+    }
+
+    @Override
+    public PagedFile map( File file, int pageSize ) throws IOException
+    {
+        adversary.injectFailure( FileNotFoundException.class, IOException.class, SecurityException.class );
+        PagedFile pagedFile = delegate.map( file, pageSize );
+        return new AdversarialPagedFile( pagedFile, adversary );
+    }
+
+    @Override
+    public void flushAndForce() throws IOException
+    {
+        adversary.injectFailure( FileNotFoundException.class, IOException.class, SecurityException.class );
+        delegate.flushAndForce();
+    }
+
+    @Override
+    public void close() throws IOException
+    {
+        adversary.injectFailure( FileNotFoundException.class, IOException.class, SecurityException.class );
+        delegate.close();
+    }
+
+    @Override
+    public int pageSize()
+    {
+        return delegate.pageSize();
+    }
+
+    @Override
+    public int maxCachedPages()
+    {
+        return delegate.maxCachedPages();
+    }
+}

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

@@ -0,0 +1,94 @@
+/*
+ * 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.adversaries.pagecache;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.util.Objects;
+
+import org.neo4j.adversaries.Adversary;
+import org.neo4j.io.pagecache.PageCursor;
+import org.neo4j.io.pagecache.PagedFile;
+
+/**
+ * A {@linkplain PagedFile paged file} that wraps another paged file and an {@linkplain Adversary adversary} to provide
+ * a misbehaving paged file implementation for testing.
+ * <p>
+ * Depending on the adversary each operation can throw either {@link RuntimeException} like {@link SecurityException}
+ * or {@link IOException} like {@link FileNotFoundException}.
+ */
+@SuppressWarnings( "unchecked" )
+class AdversarialPagedFile implements PagedFile
+{
+    private final PagedFile delegate;
+    private final Adversary adversary;
+
+    AdversarialPagedFile( PagedFile delegate, Adversary adversary )
+    {
+        this.delegate = Objects.requireNonNull( delegate );
+        this.adversary = Objects.requireNonNull( adversary );
+    }
+
+    @Override
+    public PageCursor io( long pageId, int pf_flags ) throws IOException
+    {
+        adversary.injectFailure( IllegalStateException.class );
+        PageCursor pageCursor = delegate.io( pageId, pf_flags );
+        if ( (pf_flags & PF_SHARED_LOCK) == PF_SHARED_LOCK )
+        {
+            return new AdversarialReadPageCursor( pageCursor, adversary );
+        }
+        return new AdversarialWritePageCursor( pageCursor, adversary );
+    }
+
+    @Override
+    public int pageSize()
+    {
+        return delegate.pageSize();
+    }
+
+    @Override
+    public void flushAndForce() throws IOException
+    {
+        adversary.injectFailure( FileNotFoundException.class, IOException.class, SecurityException.class );
+        delegate.flushAndForce();
+    }
+
+    @Override
+    public void force() throws IOException
+    {
+        adversary.injectFailure( IOException.class, SecurityException.class );
+        delegate.force();
+    }
+
+    @Override
+    public long getLastPageId() throws IOException
+    {
+        adversary.injectFailure( IllegalStateException.class );
+        return delegate.getLastPageId();
+    }
+
+    @Override
+    public void close() throws IOException
+    {
+        adversary.injectFailure( FileNotFoundException.class, IOException.class, SecurityException.class );
+        delegate.close();
+    }
+}