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/*-*- mode: Java; tab-width:8 -*-*/

package io.soluble.pjb.script;

/*
 * Copyright (C) 2003-2007 Jost Boekemeier
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

import java.io.IOException;
import java.io.OutputStream;
import java.util.Map;

import io.soluble.pjb.bridge.Util;
import io.soluble.pjb.bridge.http.HeaderParser;

/**
 * This class represents the logic to run PHP scripts through CGI, FastCGI or on a remote HTTP server
 * (accessed through URLReader).
 *
 * @author jostb
 * @see io.soluble.pjb.bridge.http.HttpServer
 * @see io.soluble.pjb.script.URLReader
 * @see io.soluble.pjb.script.HttpProxy
 */

public abstract class Continuation implements IContinuation, Runnable {

    protected Map env;
    protected OutputStream out, err;
    //   protected Reader reader;
    protected HeaderParser headerParser;
    protected ResultProxy resultProxy;

    private ScriptLock scriptLock = new ScriptLock();
    private Lock phpScript = new Lock();

    // used to wait for the script to terminate
    private static class ScriptLock {
        private boolean running = true;

        public synchronized void waitForRunner() throws InterruptedException {
            if (running)
                wait();
        }

        public synchronized void finish() {
            running = false;
            notify();
        }
    }

    // used to wait for the cont.call(cont) call from the script
    protected class Lock {
        private Object val = null;
        private boolean finish = false;

        public synchronized Object getVal() {
            if (!finish && val == null)
                try {
                    wait();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            return val;
        }

        public synchronized void setVal(Object val) {
            this.val = val;
            notify();
        }

        public synchronized void finish() {
            finish = true;
            notify();
        }
    }

    protected Continuation(Map env, OutputStream out, OutputStream err, HeaderParser headerParser, ResultProxy resultProxy) {
        this.env = env;
        this.out = out;
        this.err = err;
        this.headerParser = headerParser;
        this.resultProxy = resultProxy;
    }

    public void run() {
        try {
            doRun();
        } catch (IOException e) {
            phpScript.val = e;
        } catch (Util.Process.PhpException e1) {
            phpScript.val = e1;
        } catch (Exception ex) {
            phpScript.val = ex;
            Util.printStackTrace(ex);
        } finally {
            phpScript.finish();
            scriptLock.finish();
        }
    }

    protected abstract void doRun() throws IOException, Util.Process.PhpException;

    private Object lockObject = new Object();

    /**
     * The PHP script must call this function with the current
     * continuation as an argument.
     * 

     * Example:
     * 
     * java_context()->call(java_closure());

     * 
     *
     * @param script - The php continuation
     * @throws InterruptedException
     */
    public void call(Object script) throws InterruptedException {
        synchronized (lockObject) {
            phpScript.setVal(script);
            lockObject.wait();
        }
    }

    /**
     * One must call this function if one is interested in the php continuation.
     *
     * @return The php continuation.
     * @throws Exception
     */
    public Object getPhpScript() throws Exception {
        Object val = phpScript.getVal();
        if (val instanceof Exception) throw (Exception) val;
        return val;
    }

    /**
     * This function must be called to release the allocated php continuation.
     * Note that simply calling this method does not guarantee that
     * the script is finished, as the ContextRunner may still produce output.
     * Use contextFactory.waitFor() to wait for the script to terminate.
     *
     * @throws InterruptedException
     */
    public void release() throws InterruptedException {
        /* Release the cont.call(cont) from PHP. After that the PHP script may terminate */
        synchronized (lockObject) {
            lockObject.notifyAll();
        }
        scriptLock.waitForRunner();
    }
}