--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/eclipse/jetty/server/ResourceCache.java	Wed Sep 07 21:15:48 2016 -0600
@@ -0,0 +1,522 @@
+//
+//  ========================================================================
+//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.server;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Comparator;
+import java.util.SortedSet;
+import java.util.TreeSet;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
+
+import org.eclipse.jetty.http.HttpContent;
+import org.eclipse.jetty.http.HttpContent.ResourceAsHttpContent;
+import org.eclipse.jetty.http.HttpFields;
+import org.eclipse.jetty.http.MimeTypes;
+import org.eclipse.jetty.io.Buffer;
+import org.eclipse.jetty.io.ByteArrayBuffer;
+import org.eclipse.jetty.io.View;
+import org.eclipse.jetty.io.nio.DirectNIOBuffer;
+import org.eclipse.jetty.io.nio.IndirectNIOBuffer;
+import org.eclipse.jetty.util.log.Log;
+import org.eclipse.jetty.util.log.Logger;
+import org.eclipse.jetty.util.resource.Resource;
+import org.eclipse.jetty.util.resource.ResourceFactory;
+
+
+/* ------------------------------------------------------------ */
+/** 
+ * 
+ */
+public class ResourceCache
+{
+    private static final Logger LOG = Log.getLogger(ResourceCache.class);
+
+    private final ConcurrentMap<String,Content> _cache;
+    private final AtomicInteger _cachedSize;
+    private final AtomicInteger _cachedFiles;
+    private final ResourceFactory _factory;
+    private final ResourceCache _parent;
+    private final MimeTypes _mimeTypes;
+    private final boolean _etags;
+
+    private boolean  _useFileMappedBuffer=true;
+    private int _maxCachedFileSize =4*1024*1024;
+    private int _maxCachedFiles=2048;
+    private int _maxCacheSize =32*1024*1024;
+    
+    /* ------------------------------------------------------------ */
+    /** Constructor.
+     * @param mimeTypes Mimetype to use for meta data
+     */
+    public ResourceCache(ResourceCache parent, ResourceFactory factory, MimeTypes mimeTypes,boolean useFileMappedBuffer,boolean etags)
+    {
+        _factory = factory;
+        _cache=new ConcurrentHashMap<String,Content>();
+        _cachedSize=new AtomicInteger();
+        _cachedFiles=new AtomicInteger();
+        _mimeTypes=mimeTypes;
+        _parent=parent;
+        _etags=etags;
+        _useFileMappedBuffer=useFileMappedBuffer;
+    }
+
+    /* ------------------------------------------------------------ */
+    public int getCachedSize()
+    {
+        return _cachedSize.get();
+    }
+    
+    /* ------------------------------------------------------------ */
+    public int getCachedFiles()
+    {
+        return _cachedFiles.get();
+    }
+    
+    /* ------------------------------------------------------------ */
+    public int getMaxCachedFileSize()
+    {
+        return _maxCachedFileSize;
+    }
+
+    /* ------------------------------------------------------------ */
+    public void setMaxCachedFileSize(int maxCachedFileSize)
+    {
+        _maxCachedFileSize = maxCachedFileSize;
+        shrinkCache();
+    }
+
+    /* ------------------------------------------------------------ */
+    public int getMaxCacheSize()
+    {
+        return _maxCacheSize;
+    }
+
+    /* ------------------------------------------------------------ */
+    public void setMaxCacheSize(int maxCacheSize)
+    {
+        _maxCacheSize = maxCacheSize;
+        shrinkCache();
+    }
+
+    /* ------------------------------------------------------------ */
+    /**
+     * @return Returns the maxCachedFiles.
+     */
+    public int getMaxCachedFiles()
+    {
+        return _maxCachedFiles;
+    }
+    
+    /* ------------------------------------------------------------ */
+    /**
+     * @param maxCachedFiles The maxCachedFiles to set.
+     */
+    public void setMaxCachedFiles(int maxCachedFiles)
+    {
+        _maxCachedFiles = maxCachedFiles;
+        shrinkCache();
+    }
+
+    /* ------------------------------------------------------------ */
+    public boolean isUseFileMappedBuffer()
+    {
+        return _useFileMappedBuffer;
+    }
+
+    /* ------------------------------------------------------------ */
+    public void setUseFileMappedBuffer(boolean useFileMappedBuffer)
+    {
+        _useFileMappedBuffer = useFileMappedBuffer;
+    }
+
+    /* ------------------------------------------------------------ */
+    public void flushCache()
+    {
+        if (_cache!=null)
+        {
+            while (_cache.size()>0)
+            {
+                for (String path : _cache.keySet())
+                {
+                    Content content = _cache.remove(path);
+                    if (content!=null)
+                        content.invalidate();
+                }
+            }
+        }
+    }
+
+    /* ------------------------------------------------------------ */
+    /** Get a Entry from the cache.
+     * Get either a valid entry object or create a new one if possible.
+     *
+     * @param pathInContext The key into the cache
+     * @return The entry matching <code>pathInContext</code>, or a new entry 
+     * if no matching entry was found. If the content exists but is not cachable, 
+     * then a {@link ResourceAsHttpContent} instance is return. If 
+     * the resource does not exist, then null is returned.
+     * @throws IOException Problem loading the resource
+     */
+    public HttpContent lookup(String pathInContext)
+        throws IOException
+    {
+        // Is the content in this cache?
+        Content content =_cache.get(pathInContext);
+        if (content!=null && (content).isValid())
+            return content;
+       
+        // try loading the content from our factory.
+        Resource resource=_factory.getResource(pathInContext);
+        HttpContent loaded = load(pathInContext,resource);
+        if (loaded!=null)
+            return loaded;
+        
+        // Is the content in the parent cache?
+        if (_parent!=null)
+        {
+            HttpContent httpContent=_parent.lookup(pathInContext);
+            if (httpContent!=null)
+                return httpContent;
+        }
+        
+        return null;
+    }
+    
+    /* ------------------------------------------------------------ */
+    /**
+     * @param resource
+     * @return True if the resource is cacheable. The default implementation tests the cache sizes.
+     */
+    protected boolean isCacheable(Resource resource)
+    {
+        long len = resource.length();
+
+        // Will it fit in the cache?
+        return  (len>0 && len<_maxCachedFileSize && len<_maxCacheSize);
+    }
+    
+    /* ------------------------------------------------------------ */
+    private HttpContent load(String pathInContext, Resource resource)
+        throws IOException
+    {
+        Content content=null;
+        
+        if (resource==null || !resource.exists())
+            return null;
+        
+        // Will it fit in the cache?
+        if (!resource.isDirectory() && isCacheable(resource))
+        {   
+            // Create the Content (to increment the cache sizes before adding the content 
+            content = new Content(pathInContext,resource);
+
+            // reduce the cache to an acceptable size.
+            shrinkCache();
+
+            // Add it to the cache.
+            Content added = _cache.putIfAbsent(pathInContext,content);
+            if (added!=null)
+            {
+                content.invalidate();
+                content=added;
+            }
+
+            return content;
+        }
+        
+        return new HttpContent.ResourceAsHttpContent(resource,_mimeTypes.getMimeByExtension(resource.toString()),getMaxCachedFileSize(),_etags);
+        
+    }
+    
+    /* ------------------------------------------------------------ */
+    private void shrinkCache()
+    {
+        // While we need to shrink
+        while (_cache.size()>0 && (_cachedFiles.get()>_maxCachedFiles || _cachedSize.get()>_maxCacheSize))
+        {
+            // Scan the entire cache and generate an ordered list by last accessed time.
+            SortedSet<Content> sorted= new TreeSet<Content>(
+                    new Comparator<Content>()
+                    {
+                        public int compare(Content c1, Content c2)
+                        {
+                            if (c1._lastAccessed<c2._lastAccessed)
+                                return -1;
+                            
+                            if (c1._lastAccessed>c2._lastAccessed)
+                                return 1;
+
+                            if (c1._length<c2._length)
+                                return -1;
+                            
+                            return c1._key.compareTo(c2._key);
+                        }
+                    });
+            for (Content content : _cache.values())
+                sorted.add(content);
+            
+            // Invalidate least recently used first
+            for (Content content : sorted)
+            {
+                if (_cachedFiles.get()<=_maxCachedFiles && _cachedSize.get()<=_maxCacheSize)
+                    break;
+                if (content==_cache.remove(content.getKey()))
+                    content.invalidate();
+            }
+        }
+    }
+    
+    /* ------------------------------------------------------------ */
+    protected Buffer getIndirectBuffer(Resource resource)
+    {
+        try
+        {
+            int len=(int)resource.length();
+            if (len<0)
+            {
+                LOG.warn("invalid resource: "+String.valueOf(resource)+" "+len);
+                return null;
+            }
+            Buffer buffer = new IndirectNIOBuffer(len);
+            InputStream is = resource.getInputStream();
+            buffer.readFrom(is,len);
+            is.close();
+            return buffer;
+        }
+        catch(IOException e)
+        {
+            LOG.warn(e);
+            return null;
+        }
+    }
+
+    /* ------------------------------------------------------------ */
+    protected Buffer getDirectBuffer(Resource resource)
+    {
+        try
+        {
+            if (_useFileMappedBuffer && resource.getFile()!=null) 
+                return new DirectNIOBuffer(resource.getFile());
+
+            int len=(int)resource.length();
+            if (len<0)
+            {
+                LOG.warn("invalid resource: "+String.valueOf(resource)+" "+len);
+                return null;
+            }
+            Buffer buffer = new DirectNIOBuffer(len);
+            InputStream is = resource.getInputStream();
+            buffer.readFrom(is,len);
+            is.close();
+            return buffer;
+        }
+        catch(IOException e)
+        {
+            LOG.warn(e);
+            return null;
+        }
+    }
+
+    /* ------------------------------------------------------------ */
+    @Override
+    public String toString()
+    {
+        return "ResourceCache["+_parent+","+_factory+"]@"+hashCode();
+    }
+    
+    /* ------------------------------------------------------------ */
+    /* ------------------------------------------------------------ */
+    /** MetaData associated with a context Resource.
+     */
+    public class Content implements HttpContent
+    {
+        final Resource _resource;
+        final int _length;
+        final String _key;
+        final long _lastModified;
+        final Buffer _lastModifiedBytes;
+        final Buffer _contentType;
+        final Buffer _etagBuffer;
+        
+        volatile long _lastAccessed;
+        AtomicReference<Buffer> _indirectBuffer=new AtomicReference<Buffer>();
+        AtomicReference<Buffer> _directBuffer=new AtomicReference<Buffer>();
+
+        /* ------------------------------------------------------------ */
+        Content(String pathInContext,Resource resource)
+        {
+            _key=pathInContext;
+            _resource=resource;
+
+            _contentType=_mimeTypes.getMimeByExtension(_resource.toString());
+            boolean exists=resource.exists();
+            _lastModified=exists?resource.lastModified():-1;
+            _lastModifiedBytes=_lastModified<0?null:new ByteArrayBuffer(HttpFields.formatDate(_lastModified));
+            
+            _length=exists?(int)resource.length():0;
+            _cachedSize.addAndGet(_length);
+            _cachedFiles.incrementAndGet();
+            _lastAccessed=System.currentTimeMillis();
+            
+            _etagBuffer=_etags?new ByteArrayBuffer(resource.getWeakETag()):null;
+        }
+
+
+        /* ------------------------------------------------------------ */
+        public String getKey()
+        {
+            return _key;
+        }
+
+        /* ------------------------------------------------------------ */
+        public boolean isCached()
+        {
+            return _key!=null;
+        }
+        
+        /* ------------------------------------------------------------ */
+        public boolean isMiss()
+        {
+            return false;
+        }
+
+        /* ------------------------------------------------------------ */
+        public Resource getResource()
+        {
+            return _resource;
+        }
+
+        /* ------------------------------------------------------------ */
+        public Buffer getETag()
+        {
+            return _etagBuffer;
+        }
+        
+        /* ------------------------------------------------------------ */
+        boolean isValid()
+        {
+            if (_lastModified==_resource.lastModified() && _length==_resource.length())
+            {
+                _lastAccessed=System.currentTimeMillis();
+                return true;
+            }
+
+            if (this==_cache.remove(_key))
+                invalidate();
+            return false;
+        }
+
+        /* ------------------------------------------------------------ */
+        protected void invalidate()
+        {
+            // Invalidate it
+            _cachedSize.addAndGet(-_length);
+            _cachedFiles.decrementAndGet();
+            _resource.release(); 
+        }
+
+        /* ------------------------------------------------------------ */
+        public Buffer getLastModified()
+        {
+            return _lastModifiedBytes;
+        }
+
+        /* ------------------------------------------------------------ */
+        public Buffer getContentType()
+        {
+            return _contentType;
+        }
+
+        /* ------------------------------------------------------------ */
+        public void release()
+        {
+            // don't release while cached. Release when invalidated.
+        }
+
+        /* ------------------------------------------------------------ */
+        public Buffer getIndirectBuffer()
+        {
+            Buffer buffer = _indirectBuffer.get();
+            if (buffer==null)
+            {
+                Buffer buffer2=ResourceCache.this.getIndirectBuffer(_resource);
+                
+                if (buffer2==null)
+                    LOG.warn("Could not load "+this);
+                else if (_indirectBuffer.compareAndSet(null,buffer2))
+                    buffer=buffer2;
+                else
+                    buffer=_indirectBuffer.get();
+            }
+            if (buffer==null)
+                return null;
+            return new View(buffer);
+        }
+        
+
+        /* ------------------------------------------------------------ */
+        public Buffer getDirectBuffer()
+        {
+            Buffer buffer = _directBuffer.get();
+            if (buffer==null)
+            {
+                Buffer buffer2=ResourceCache.this.getDirectBuffer(_resource);
+
+                if (buffer2==null)
+                    LOG.warn("Could not load "+this);
+                else if (_directBuffer.compareAndSet(null,buffer2))
+                    buffer=buffer2;
+                else
+                    buffer=_directBuffer.get();
+            }
+            if (buffer==null)
+                return null;
+                        
+            return new View(buffer);
+        }
+        
+        /* ------------------------------------------------------------ */
+        public long getContentLength()
+        {
+            return _length;
+        }
+
+        /* ------------------------------------------------------------ */
+        public InputStream getInputStream() throws IOException
+        {
+            Buffer indirect = getIndirectBuffer();
+            if (indirect!=null && indirect.array()!=null)
+                return new ByteArrayInputStream(indirect.array(),indirect.getIndex(),indirect.length());
+           
+            return _resource.getInputStream();
+        }   
+
+        /* ------------------------------------------------------------ */
+        @Override
+        public String toString()
+        {
+            return String.format("%s %s %d %s %s",_resource,_resource.exists(),_resource.lastModified(),_contentType,_lastModifiedBytes);
+        }   
+    }
+}