fcgioutputstream.java

FastCGI,语言无关的、可伸缩架构的CGI开放扩展

/*
 * @(#)FCGIOutputStream.java
 *
 *      FastCGi compatibility package Interface
 *
 *  Copyright (c) 1996 Open Market, Inc.
 *
 * See the file "LICENSE.TERMS" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * $Id: FCGIOutputStream.java,v 1.3 2000/03/21 12:12:26 robs Exp $
 */
package com.fastcgi;

import java.io.*;

/**
 * This stream understands FCGI prototcol.
 */

public class FCGIOutputStream 
    extends OutputStream 
{
    private static final String RCSID = "$Id: FCGIOutputStream.java,v 1.3 2000/03/21 12:12:26 robs Exp $";

    /* Stream vars */

    public int wrNext;
    public int stop;
    public boolean isClosed;

    /* require methods to set, get and clear */
    private int errno;
    private Exception errex;

    /* data vars */

    public byte buff[];
    public int buffLen;
    public int buffStop;
    public int type;
    public boolean isAnythingWritten;
    public boolean rawWrite;
    public FCGIRequest request;

    public FileOutputStream out;

    /**
    * Creates a new output stream to manage fcgi prototcol stuff
    * @param out the output stream  buflen  length of buffer streamType
    */
    public FCGIOutputStream(FileOutputStream outStream,
        int bufLen, int streamType,
        FCGIRequest inreq) {
        out = outStream;
        buffLen = Math.min(bufLen, FCGIGlobalDefs.def_FCGIMaxLen);
        buff = new byte[buffLen];
        type = streamType;
        stop = buffStop = buffLen;
        isAnythingWritten = false;
        rawWrite = false;
        wrNext = FCGIGlobalDefs.def_FCGIHeaderLen;
        isClosed = false;
        request = inreq;
    }

    /**
    * Writes a byte to the output stream.
    */
    public void  write(int c) throws IOException {
        if(wrNext != stop) {
            buff[wrNext++] = (byte)c;
            return;
        }
        if(isClosed) {
            throw new EOFException();
        }
        empty(false);
        if(wrNext != stop) {
            buff[wrNext++] = (byte)c;
            return;
        }
        /* NOTE: ASSERT(stream->isClosed); */
        /* bug in emptyBuffProc if not */
        throw new EOFException();
    }

    /**
    * Writes an array of bytes. This method will block until the bytes
    * are actually written.
    * @param b  the data to be written
    */
    public  void write(byte b[]) throws IOException{
        write(b, 0, b.length);
    }

    /**
    * Writes len consecutive bytes from off in the array b
    * into the output stream.  Performs no interpretation
    * of the output bytes. Making the user convert the string to
    * bytes is in line with current Java practice.
    */
    public void write(byte b[], int off, int len) throws IOException {
        int m, bytesMoved;
        /*
        * Fast path: room for n bytes in the buffer
        */
        if(len <= (stop - wrNext)) {
            System.arraycopy(b, off, buff, wrNext, len);
            wrNext += len;
            return;
        }
        /*
        * General case: stream is closed or buffer empty procedure
        * needs to be called
        */
        bytesMoved = 0;
        for (;;) {
            if(wrNext != stop) {
                m = Math.min(len - bytesMoved, stop - wrNext);
                System.arraycopy(b, off, buff, wrNext, m);
                bytesMoved += m;
                wrNext += m;
                if(bytesMoved == len) {
                    return;
                }
                off += m;
            }
            if(isClosed) {
                throw new EOFException();
            }
            empty(false);
        }
    }

    /**
    * Encapsulates any buffered stream content in a FastCGI
    * record.  If !doClose, writes the data, making the buffer
    * empty.
    */
    public void empty(boolean doClose) throws IOException {
        int cLen;
        /*
        * Alignment padding omitted in Java
        */
        if (!rawWrite) {
            cLen = wrNext - FCGIGlobalDefs.def_FCGIHeaderLen;
            if(cLen > 0) {
                System.arraycopy(new FCGIMessage().makeHeader(type,
                    request.requestID, cLen, 0),
                    0, buff, 0,
                    FCGIGlobalDefs.def_FCGIHeaderLen);
            }
            else {
                wrNext = 0;
            }
        }
        if (doClose) {
            writeCloseRecords();
        }
        if (wrNext != 0) {
            isAnythingWritten = true;
            try {
                out.write(buff, 0, wrNext);
            } catch (IOException e) {
                setException(e);
                return;
            }
            wrNext = 0;
        }
        /*
        * The buffer is empty.
        */
        if(!rawWrite) {
            wrNext += FCGIGlobalDefs.def_FCGIHeaderLen;
        }
    }

    /**
    * Close the stream.
    */
    public void  close() throws IOException {
        if (isClosed) {
            return;
        }
        empty(true);
        /*
        * if isClosed, will return with EOFException from write.
        */
        isClosed = true;
        stop = wrNext;
        return;
    }

    /**
    * Flushes any buffered output.
    * Server-push is a legitimate application of flush.
    * Otherwise, it is not very useful, since FCGIAccept
    * does it implicitly.  flush may reduce performance
    * by increasing the total number of operating system calls
    * the application makes.
    */
    public void flush() throws IOException {
        if (isClosed) {
            return;
        }
        empty(false);
        /*
        * if isClosed, will return with EOFException from write.
        */
        return;
    }

    /**
    * An FCGI error has occurred. Save the error code in the stream
    * for diagnostic purposes and set the stream state so that
    * reads return EOF
    */
    public void setFCGIError(int errnum) {
        /*
        * Preserve only the first error.
        */
        if (errno == 0) {
            errno = errnum;
        }
        isClosed = true;
    }

    /**
    * An Exception has occurred. Save the Exception in the stream
    * for diagnostic purposes and set the stream state so that
    * reads return EOF
    */
    public void setException(Exception errexpt) {
        /*
        * Preserve only the first error.
        */
        if (errex == null) {
            errex = errexpt;
        }
        isClosed = true;
    }

    /**
    * Clear the stream error code and end-of-file indication.
    */
    public void clearFCGIError() {
        errno = 0;
        /*
        * isClosed = false;
        * XXX: should clear isClosed but work is needed to make it safe
        * to do so.
        */
    }

    /**
    * Clear the stream error code and end-of-file indication.
    */
    public void clearException() {
        errex = null;
        /*
        * isClosed = false;
        * XXX: should clear isClosed but work is needed to make it safe
        * to do so.
        */
    }

    /**
    * accessor method since var is private
    */
    public int etFCGIError() {
        return errno;
    }

    /**
    * accessor method since var is private
    */
    public Exception getException() {
        return errex;
    }

    /**
    * Writes an EOF record for the stream content if necessary.
    * If this is the last writer to close, writes an FCGI_END_REQUEST
    * record.
    */
    public void writeCloseRecords() throws IOException {
        FCGIMessage msg = new FCGIMessage();
        /*
        * Enter rawWrite mode so final records won't be
        * encapsulated as
        * stream data.
        */
        rawWrite = true;
        /*
        * Generate EOF for stream content if needed.
        */
        if(!(type == FCGIGlobalDefs.def_FCGIStderr
            && wrNext == 0
            && !isAnythingWritten)) {
            byte hdr[] =
                new byte[FCGIGlobalDefs.def_FCGIHeaderLen];
            System.arraycopy(msg.makeHeader(type,
                request.requestID,
                0, 0),
                0, hdr,0,
                FCGIGlobalDefs.def_FCGIHeaderLen);
            write(hdr, 0, hdr.length);
        }
        /*
        * Generate FCGI_END_REQUEST record if needed.
        */
        if(request.numWriters == 1) {
            byte endReq[] =
                new byte[FCGIGlobalDefs.def_FCGIHeaderLen
                + FCGIGlobalDefs.def_FCGIEndReqBodyLen];
            System.arraycopy(msg.makeHeader(
                FCGIGlobalDefs.def_FCGIEndRequest,
                request.requestID,
                FCGIGlobalDefs.def_FCGIEndReqBodyLen,0),
                0, endReq, 0,
                FCGIGlobalDefs.def_FCGIHeaderLen);
            System.arraycopy(msg.makeEndrequestBody(
                request.appStatus,
                FCGIGlobalDefs.def_FCGIRequestComplete),
                0,endReq,
                FCGIGlobalDefs.def_FCGIHeaderLen,
                FCGIGlobalDefs.def_FCGIEndReqBodyLen);
            write(endReq,0, FCGIGlobalDefs.def_FCGIHeaderLen
                + FCGIGlobalDefs.def_FCGIEndReqBodyLen);
        }
        request.numWriters--;
    }
}