/*
 * Copyright (C) 2009-2010, Google Inc. and others
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0 which is available at
 * https://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package org.eclipse.jgit.http.server;

import java.util.Enumeration;

import javax.servlet.Filter;
import javax.servlet.FilterConfig;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;

import org.eclipse.jgit.http.server.glue.MetaServlet;
import org.eclipse.jgit.http.server.resolver.AsIsFileService;
import org.eclipse.jgit.transport.resolver.ReceivePackFactory;
import org.eclipse.jgit.transport.resolver.RepositoryResolver;
import org.eclipse.jgit.transport.resolver.UploadPackFactory;

/**
 * Handles Git repository access over HTTP.
 * <p>
 * Applications embedding this servlet should map a directory path within the
 * application to this servlet, for example:
 *
 * <pre>
 *   &lt;servlet&gt;
 *     &lt;servlet-name&gt;GitServlet&lt;/servlet-name&gt;
 *     &lt;servlet-class&gt;org.eclipse.jgit.http.server.GitServlet&lt;/servlet-class&gt;
 *     &lt;init-param&gt;
 *       &lt;param-name&gt;base-path&lt;/param-name&gt;
 *       &lt;param-value&gt;/var/srv/git&lt;/param-value&gt;
 *     &lt;/init-param&gt;
 *     &lt;init-param&gt;
 *       &lt;param-name&gt;export-all&lt;/param-name&gt;
 *       &lt;param-value&gt;0&lt;/param-value&gt;
 *     &lt;/init-param&gt;
 * &lt;/servlet&gt;
 *   &lt;servlet-mapping&gt;
 *     &lt;servlet-name&gt;GitServlet&lt;/servlet-name&gt;
 *     &lt;url-pattern&gt;/git/*&lt;/url-pattern&gt;
 *   &lt;/servlet-mapping&gt;
 * </pre>
 *
 * <p>
 * Applications may wish to add additional repository action URLs to this
 * servlet by taking advantage of its extension from
 * {@link org.eclipse.jgit.http.server.glue.MetaServlet}. Callers may register
 * their own URL suffix translations through {@link #serve(String)}, or their
 * regex translations through {@link #serveRegex(String)}. Each translation
 * should contain a complete filter pipeline which ends with the HttpServlet
 * that should handle the requested action.
 */
public class GitServlet extends MetaServlet {
	private static final long serialVersionUID = 1L;

	private final GitFilter gitFilter;

	/**
	 * New servlet that will load its base directory from {@code web.xml}.
	 * <p>
	 * The required parameter {@code base-path} must be configured to point to
	 * the local filesystem directory where all served Git repositories reside.
	 */
	public GitServlet() {
		super(new GitFilter());
		gitFilter = (GitFilter) getDelegateFilter();
	}

	/**
	 * New servlet configured with a specific resolver.
	 *
	 * @param resolver
	 *            the resolver to use when matching URL to Git repository. If
	 *            null the {@code base-path} parameter will be looked for in the
	 *            parameter table during init, which usually comes from the
	 *            {@code web.xml} file of the web application.
	 */
	public void setRepositoryResolver(RepositoryResolver<HttpServletRequest> resolver) {
		gitFilter.setRepositoryResolver(resolver);
	}

	/**
	 * Set AsIsFileService
	 *
	 * @param f
	 *            the filter to validate direct access to repository files
	 *            through a dumb client. If {@code null} then dumb client
	 *            support is completely disabled.
	 */
	public void setAsIsFileService(AsIsFileService f) {
		gitFilter.setAsIsFileService(f);
	}

	/**
	 * Set upload-pack factory
	 *
	 * @param f
	 *            the factory to construct and configure an
	 *            {@link org.eclipse.jgit.transport.UploadPack} session when a
	 *            fetch or clone is requested by a client.
	 */
	public void setUploadPackFactory(UploadPackFactory<HttpServletRequest> f) {
		gitFilter.setUploadPackFactory(f);
	}

	/**
	 * Add upload-pack filter
	 *
	 * @param filter
	 *            filter to apply before any of the UploadPack operations. The
	 *            UploadPack instance is available in the request attribute
	 *            {@link org.eclipse.jgit.http.server.ServletUtils#ATTRIBUTE_HANDLER}.
	 */
	public void addUploadPackFilter(Filter filter) {
		gitFilter.addUploadPackFilter(filter);
	}

	/**
	 * Set receive-pack factory
	 *
	 * @param f
	 *            the factory to construct and configure a
	 *            {@link org.eclipse.jgit.transport.ReceivePack} session when a
	 *            push is requested by a client.
	 */
	public void setReceivePackFactory(ReceivePackFactory<HttpServletRequest> f) {
		gitFilter.setReceivePackFactory(f);
	}

	/**
	 * Add receive-pack filter
	 *
	 * @param filter
	 *            filter to apply before any of the ReceivePack operations. The
	 *            ReceivePack instance is available in the request attribute
	 *            {@link org.eclipse.jgit.http.server.ServletUtils#ATTRIBUTE_HANDLER}.
	 */
	public void addReceivePackFilter(Filter filter) {
		gitFilter.addReceivePackFilter(filter);
	}

	/** {@inheritDoc} */
	@Override
	public void init(ServletConfig config) throws ServletException {
		gitFilter.init(new FilterConfig() {
			@Override
			public String getFilterName() {
				return gitFilter.getClass().getName();
			}

			@Override
			public String getInitParameter(String name) {
				return config.getInitParameter(name);
			}

			@Override
			public Enumeration<String> getInitParameterNames() {
				return config.getInitParameterNames();
			}

			@Override
			public ServletContext getServletContext() {
				return config.getServletContext();
			}
		});
	}
}