/*
* Copyright (C) 2009-2010, Google Inc.
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.eclipse.jgit.http.server.glue;
import java.io.IOException;
import java.text.MessageFormat;
import java.util.AbstractSet;
import java.util.ArrayList;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.regex.Pattern;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.eclipse.jgit.http.server.HttpServerText;
/**
* Generic container filter to manage routing to different pipelines.
* <p>
* Callers can create and configure a new processing pipeline by using one of
* the {@link #serve(String)} or {@link #serveRegex(String)} methods to allocate
* a binder for a particular URL pattern.
* <p>
* Registered filters and servlets are initialized lazily, usually during the
* first request. Once initialized the bindings in this servlet cannot be
* modified without destroying the servlet and thereby destroying all registered
* filters and servlets.
*/
public class MetaFilter implements Filter {
static final String REGEX_GROUPS = "org.eclipse.jgit.http.server.glue.MetaServlet.serveRegex";
private ServletContext servletContext;
private final List<ServletBinderImpl> bindings;
private volatile UrlPipeline[] pipelines;
/** Empty filter with no bindings. */
public MetaFilter() {
this.bindings = new ArrayList<ServletBinderImpl>();
}
/**
* Construct a binding for a specific path.
*
* @param path
* pattern to match.
* @return binder for the passed path.
*/
public ServletBinder serve(String path) {
if (path.startsWith("*"))
return register(new SuffixPipeline.Binder(path.substring(1)));
throw new IllegalArgumentException(MessageFormat.format(HttpServerText
.get().pathNotSupported, path));
}
/**
* Construct a binding for a regular expression.
*
* @param expression
* the regular expression to pattern match the URL against.
* @return binder for the passed expression.
*/
public ServletBinder serveRegex(String expression) {
return register(new RegexPipeline.Binder(expression));
}
/**
* Construct a binding for a regular expression.
*
* @param pattern
* the regular expression to pattern match the URL against.
* @return binder for the passed expression.
*/
public ServletBinder serveRegex(Pattern pattern) {
return register(new RegexPipeline.Binder(pattern));
}
public void init(FilterConfig filterConfig) throws ServletException {
servletContext = filterConfig.getServletContext();
}
public void destroy() {
if (pipelines != null) {
Set<Object> destroyed = newIdentitySet();
for (UrlPipeline p : pipelines)
p.destroy(destroyed);
pipelines = null;
}
}
private static Set<Object> newIdentitySet() {
final Map<Object, Object> m = new IdentityHashMap<Object, Object>();
return new AbstractSet<Object>() {
@Override
public boolean add(Object o) {
return m.put(o, o) == null;
}
@Override
public boolean contains(Object o) {
return m.keySet().contains(o);
}
@Override
public Iterator<Object> iterator() {
return m.keySet().iterator();
}
@Override
public int size() {
return m.size();
}
};
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest) request;
HttpServletResponse res = (HttpServletResponse) response;
UrlPipeline p = find(req);
if (p != null)
p.service(req, res);
else
chain.doFilter(req, res);
}
private UrlPipeline find(HttpServletRequest req) throws ServletException {
for (UrlPipeline p : getPipelines())
if (p.match(req))
return p;
return null;
}
private ServletBinder register(ServletBinderImpl b) {
synchronized (bindings) {
if (pipelines != null)
throw new IllegalStateException(
HttpServerText.get().servletAlreadyInitialized);
bindings.add(b);
}
return register((ServletBinder) b);
}
/**
* Configure a newly created binder.
*
* @param b
* the newly created binder.
* @return binder for the caller, potentially after adding one or more
* filters into the pipeline.
*/
protected ServletBinder register(ServletBinder b) {
return b;
}
private UrlPipeline[] getPipelines() throws ServletException {
UrlPipeline[] r = pipelines;
if (r == null) {
synchronized (bindings) {
r = pipelines;
if (r == null) {
r = createPipelines();
pipelines = r;
}
}
}
return r;
}
private UrlPipeline[] createPipelines() throws ServletException {
UrlPipeline[] array = new UrlPipeline[bindings.size()];
for (int i = 0; i < bindings.size(); i++)
array[i] = bindings.get(i).create();
Set<Object> inited = newIdentitySet();
for (UrlPipeline p : array)
p.init(servletContext, inited);
return array;
}
}