/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


package org.apache.catalina.core;


import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletRequestEvent;
import javax.servlet.ServletRequestListener;
import javax.servlet.http.HttpServletResponse;

import org.apache.catalina.CometEvent;
import org.apache.catalina.Container;
import org.apache.catalina.Globals;
import org.apache.catalina.Wrapper;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.util.StringManager;
import org.apache.catalina.valves.ValveBase;
import org.apache.tomcat.util.buf.MessageBytes;

/**
 * Valve that implements the default basic behavior for the
 * <code>StandardContext</code> container implementation.
 * <p>
 * <b>USAGE CONSTRAINT</b>:  This implementation is likely to be useful only
 * when processing HTTP requests.
 *
 * @author Craig R. McClanahan
 * @version $Id: StandardContextValve.java 939336 2010-04-29 15:00:41Z kkolinko $
 */

final class StandardContextValve
    extends ValveBase {


    // ----------------------------------------------------- Instance Variables


    /**
     * The descriptive information related to this implementation.
     */
    private static final String info =
        "org.apache.catalina.core.StandardContextValve/1.0";


    /**
     * The string manager for this package.
     */
    private static final StringManager sm =
        StringManager.getManager(Constants.Package);


    private StandardContext context = null;
    

    // ------------------------------------------------------------- Properties


    /**
     * Return descriptive information about this Valve implementation.
     */
    public String getInfo() {

        return (info);

    }


    // --------------------------------------------------------- Public Methods


    /**
     * Cast to a StandardContext right away, as it will be needed later.
     * 
     * @see org.apache.catalina.Contained#setContainer(org.apache.catalina.Container)
     */
    public void setContainer(Container container) {
        super.setContainer(container);
        context = (StandardContext) container;
    }

    
    /**
     * Select the appropriate child Wrapper to process this request,
     * based on the specified request URI.  If no matching Wrapper can
     * be found, return an appropriate HTTP error.
     *
     * @param request Request to be processed
     * @param response Response to be produced
     * @param valveContext Valve context used to forward to the next Valve
     *
     * @exception IOException if an input/output error occurred
     * @exception ServletException if a servlet error occurred
     */
    public final void invoke(Request request, Response response)
        throws IOException, ServletException {

        // Disallow any direct access to resources under WEB-INF or META-INF
        MessageBytes requestPathMB = request.getRequestPathMB();
        if ((requestPathMB.startsWithIgnoreCase("/META-INF/", 0))
            || (requestPathMB.equalsIgnoreCase("/META-INF"))
            || (requestPathMB.startsWithIgnoreCase("/WEB-INF/", 0))
            || (requestPathMB.equalsIgnoreCase("/WEB-INF"))) {
            notFound(response);
            return;
        }

        // Wait if we are reloading
        boolean reloaded = false;
        while (context.getPaused()) {
            reloaded = true;
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                ;
            }
        }

        // Reloading will have stopped the old webappclassloader and
        // created a new one
        if (reloaded &&
                context.getLoader() != null &&
                context.getLoader().getClassLoader() != null) {
            Thread.currentThread().setContextClassLoader(
                    context.getLoader().getClassLoader());
        }

        // Select the Wrapper to be used for this Request
        Wrapper wrapper = request.getWrapper();
        if (wrapper == null) {
            notFound(response);
            return;
        } else if (wrapper.isUnavailable()) {
            // May be as a result of a reload, try and find the new wrapper
            wrapper = (Wrapper) container.findChild(wrapper.getName());
            if (wrapper == null) {
                notFound(response);
                return;
            }
        }

        // Normal request processing
        Object instances[] = context.getApplicationEventListeners();

        ServletRequestEvent event = null;

        if ((instances != null) 
                && (instances.length > 0)) {
            event = new ServletRequestEvent
                (((StandardContext) container).getServletContext(), 
                 request.getRequest());
            // create pre-service event
            for (int i = 0; i < instances.length; i++) {
                if (instances[i] == null)
                    continue;
                if (!(instances[i] instanceof ServletRequestListener))
                    continue;
                ServletRequestListener listener =
                    (ServletRequestListener) instances[i];
                try {
                    listener.requestInitialized(event);
                } catch (Throwable t) {
                    container.getLogger().error(sm.getString("standardContext.requestListener.requestInit",
                                     instances[i].getClass().getName()), t);
                    ServletRequest sreq = request.getRequest();
                    sreq.setAttribute(Globals.EXCEPTION_ATTR,t);
                    return;
                }
            }
        }

        wrapper.getPipeline().getFirst().invoke(request, response);

        if ((instances !=null ) &&
                (instances.length > 0)) {
            // create post-service event
            for (int i = 0; i < instances.length; i++) {
                if (instances[i] == null)
                    continue;
                if (!(instances[i] instanceof ServletRequestListener))
                    continue;
                ServletRequestListener listener =
                    (ServletRequestListener) instances[i];
                try {
                    listener.requestDestroyed(event);
                } catch (Throwable t) {
                    container.getLogger().error(sm.getString("standardContext.requestListener.requestDestroy",
                                     instances[i].getClass().getName()), t);
                    ServletRequest sreq = request.getRequest();
                    sreq.setAttribute(Globals.EXCEPTION_ATTR,t);
                }
            }
        }
                
    }


    /**
     * Select the appropriate child Wrapper to process this request,
     * based on the specified request URI.  If no matching Wrapper can
     * be found, return an appropriate HTTP error.
     *
     * @param request Request to be processed
     * @param response Response to be produced
     * @param valveContext Valve context used to forward to the next Valve
     *
     * @exception IOException if an input/output error occurred
     * @exception ServletException if a servlet error occurred
     */
    public final void event(Request request, Response response, CometEvent event)
        throws IOException, ServletException {

        // Select the Wrapper to be used for this Request
        Wrapper wrapper = request.getWrapper();

        // Normal request processing
        // FIXME: This could be an addition to the core API too
        /*
        Object instances[] = context.getApplicationEventListeners();

        ServletRequestEvent event = null;

        if ((instances != null) 
                && (instances.length > 0)) {
            event = new ServletRequestEvent
                (((StandardContext) container).getServletContext(), 
                 request.getRequest());
            // create pre-service event
            for (int i = 0; i < instances.length; i++) {
                if (instances[i] == null)
                    continue;
                if (!(instances[i] instanceof ServletRequestListener))
                    continue;
                ServletRequestListener listener =
                    (ServletRequestListener) instances[i];
                try {
                    listener.requestInitialized(event);
                } catch (Throwable t) {
                    container.getLogger().error(sm.getString("requestListenerValve.requestInit",
                                     instances[i].getClass().getName()), t);
                    ServletRequest sreq = request.getRequest();
                    sreq.setAttribute(Globals.EXCEPTION_ATTR,t);
                    return;
                }
            }
        }
        */

        wrapper.getPipeline().getFirst().event(request, response, event);

        /*
        if ((instances !=null ) &&
                (instances.length > 0)) {
            // create post-service event
            for (int i = 0; i < instances.length; i++) {
                if (instances[i] == null)
                    continue;
                if (!(instances[i] instanceof ServletRequestListener))
                    continue;
                ServletRequestListener listener =
                    (ServletRequestListener) instances[i];
                try {
                    listener.requestDestroyed(event);
                } catch (Throwable t) {
                    container.getLogger().error(sm.getString("requestListenerValve.requestDestroy",
                                     instances[i].getClass().getName()), t);
                    ServletRequest sreq = request.getRequest();
                    sreq.setAttribute(Globals.EXCEPTION_ATTR,t);
                }
            }
        }
        */
      
    }


    // -------------------------------------------------------- Private Methods


    /**
     * Report a "not found" error for the specified resource.  FIXME:  We
     * should really be using the error reporting settings for this web
     * application, but currently that code runs at the wrapper level rather
     * than the context level.
     *
     * @param response The response we are creating
     */
    private void notFound(HttpServletResponse response) {

        try {
            response.sendError(HttpServletResponse.SC_NOT_FOUND);
        } catch (IllegalStateException e) {
            ;
        } catch (IOException e) {
            ;
        }

    }


}
