300 lines · 10.7 KB · Java
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/* * Copyright (c) 2004, 2008, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */package sun.net.www.http; import java.io.*; /** * OutputStream that sends the output to the underlying stream using chunked * encoding as specified in RFC 2068. */public class ChunkedOutputStream extends PrintStream {     /* Default chunk size (including chunk header) if not specified */    static final int DEFAULT_CHUNK_SIZE = 4096;    private static final byte[] CRLF = {'\r', '\n'};    private static final int CRLF_SIZE = CRLF.length;    private static final byte[] FOOTER = CRLF;    private static final int FOOTER_SIZE = CRLF_SIZE;    private static final byte[] EMPTY_CHUNK_HEADER = getHeader(0);    private static final int EMPTY_CHUNK_HEADER_SIZE = getHeaderSize(0);     /* internal buffer */    private byte buf[];    /* size of data (excluding footers and headers) already stored in buf */    private int size;    /* current index in buf (i.e. buf[count] */    private int count;    /* number of bytes to be filled up to complete a data chunk     * currently being built */    private int spaceInCurrentChunk;     /* underlying stream */    private PrintStream out;     /* the chunk size we use */    private int preferredChunkDataSize;    private int preferedHeaderSize;    private int preferredChunkGrossSize;    /* header for a complete Chunk */    private byte[] completeHeader;     /* return the size of the header for a particular chunk size */    private static int getHeaderSize(int size) {        return (Integer.toHexString(size)).length() + CRLF_SIZE;    }     /* return a header for a particular chunk size */    private static byte[] getHeader(int size){        try {            String hexStr =  Integer.toHexString(size);            byte[] hexBytes = hexStr.getBytes("US-ASCII");            byte[] header = new byte[getHeaderSize(size)];            for (int i=0; i<hexBytes.length; i++)                header[i] = hexBytes[i];            header[hexBytes.length] = CRLF[0];            header[hexBytes.length+1] = CRLF[1];            return header;        } catch (java.io.UnsupportedEncodingException e) {            /* This should never happen */            throw new InternalError(e.getMessage());        }    }     public ChunkedOutputStream(PrintStream o) {        this(o, DEFAULT_CHUNK_SIZE);    }     public ChunkedOutputStream(PrintStream o, int size) {        super(o);        out = o;         if (size <= 0) {            size = DEFAULT_CHUNK_SIZE;        }         /* Adjust the size to cater for the chunk header - eg: if the         * preferred chunk size is 1k this means the chunk size should         * be 1017 bytes (differs by 7 from preferred size because of         * 3 bytes for chunk size in hex and CRLF (header) and CRLF (footer)).         *         * If headerSize(adjusted_size) is shorter then headerSize(size)         * then try to use the extra byte unless headerSize(adjusted_size+1)         * increases back to headerSize(size)         */        if (size > 0) {            int adjusted_size = size - getHeaderSize(size) - FOOTER_SIZE;            if (getHeaderSize(adjusted_size+1) < getHeaderSize(size)){                adjusted_size++;            }            size = adjusted_size;        }         if (size > 0) {            preferredChunkDataSize = size;        } else {            preferredChunkDataSize = DEFAULT_CHUNK_SIZE -                    getHeaderSize(DEFAULT_CHUNK_SIZE) - FOOTER_SIZE;        }         preferedHeaderSize = getHeaderSize(preferredChunkDataSize);        preferredChunkGrossSize = preferedHeaderSize + preferredChunkDataSize                + FOOTER_SIZE;        completeHeader = getHeader(preferredChunkDataSize);         /* start with an initial buffer */        buf = new byte[preferredChunkDataSize + 32];        reset();    }     /*     * Flush a buffered, completed chunk to an underlying stream. If the data in     * the buffer is insufficient to build up a chunk of "preferredChunkSize"     * then the data do not get flushed unless flushAll is true. If flushAll is     * true then the remaining data builds up a last chunk which size is smaller     * than preferredChunkSize, and then the last chunk gets flushed to     * underlying stream. If flushAll is true and there is no data in a buffer     * at all then an empty chunk (containing a header only) gets flushed to     * underlying stream.     */     private void flush(boolean flushAll) {        if (spaceInCurrentChunk == 0) {            /* flush a completed chunk to underlying stream */            out.write(buf, 0, preferredChunkGrossSize);            out.flush();            reset();        } else if (flushAll){            /* complete the last chunk and flush it to underlying stream */            if (size > 0){                /* adjust a header start index in case the header of the last                 * chunk is shorter then preferedHeaderSize */                 int adjustedHeaderStartIndex = preferedHeaderSize -                        getHeaderSize(size);                 /* write header */                System.arraycopy(getHeader(size), 0, buf,                        adjustedHeaderStartIndex, getHeaderSize(size));                 /* write footer */                buf[count++] = FOOTER[0];                buf[count++] = FOOTER[1];                 //send the last chunk to underlying stream                out.write(buf, adjustedHeaderStartIndex, count - adjustedHeaderStartIndex);            } else {                //send an empty chunk (containing just a header) to underlying stream                out.write(EMPTY_CHUNK_HEADER, 0, EMPTY_CHUNK_HEADER_SIZE);            }             out.flush();            reset();         }    }     @Override    public boolean checkError() {        return out.checkError();    }     /* Check that the output stream is still open */    private void ensureOpen() {        if (out == null)            setError();    }    /*    * Writes data from b[] to an internal buffer and stores the data as data    * chunks of a following format: {Data length in Hex}{CRLF}{data}{CRLF}    * The size of the data is preferredChunkSize. As soon as a completed chunk    * is read from b[] a process of reading from b[] suspends, the chunk gets    * flushed to the underlying stream and then the reading process from b[]    * continues. When there is no more sufficient data in b[] to build up a    * chunk of preferredChunkSize size the data get stored as an incomplete    * chunk of a following format: {space for data length}{CRLF}{data}    * The size of the data is of course smaller than preferredChunkSize.    */    @Override    public synchronized void write(byte b[], int off, int len) {        ensureOpen();        if ((off < 0) || (off > b.length) || (len < 0) ||            ((off + len) > b.length) || ((off + len) < 0)) {            throw new IndexOutOfBoundsException();        } else if (len == 0) {            return;        }         /* if b[] contains enough data then one loop cycle creates one complete         * data chunk with a header, body and a footer, and then flushes the         * chunk to the underlying stream. Otherwise, the last loop cycle         * creates incomplete data chunk with empty header and with no footer         * and stores this incomplete chunk in an internal buffer buf[]         */        int bytesToWrite = len;        int inputIndex = off;  /* the index of the byte[] currently being written */         do {            /* enough data to complete a chunk */            if (bytesToWrite >= spaceInCurrentChunk) {                 /* header */                for (int i=0; i<completeHeader.length; i++)                    buf[i] = completeHeader[i];                 /* data */                System.arraycopy(b, inputIndex, buf, count, spaceInCurrentChunk);                inputIndex += spaceInCurrentChunk;                bytesToWrite -= spaceInCurrentChunk;                count += spaceInCurrentChunk;                 /* footer */                buf[count++] = FOOTER[0];                buf[count++] = FOOTER[1];                spaceInCurrentChunk = 0; //chunk is complete                 flush(false);                if (checkError()){                    break;                }            }             /* not enough data to build a chunk */            else {                /* header */                /* do not write header if not enough bytes to build a chunk yet */                 /* data */                System.arraycopy(b, inputIndex, buf, count, bytesToWrite);                count += bytesToWrite;                size += bytesToWrite;                spaceInCurrentChunk -= bytesToWrite;                bytesToWrite = 0;                 /* footer */                /* do not write header if not enough bytes to build a chunk yet */            }        } while (bytesToWrite > 0);    }     @Override    public synchronized void write(int _b) {        byte b[] = {(byte)_b};        write(b, 0, 1);    }     public synchronized void reset() {        count = preferedHeaderSize;        size = 0;        spaceInCurrentChunk = preferredChunkDataSize;    }     public int size() {        return size;    }     @Override    public synchronized void close() {        ensureOpen();         /* if we have buffer a chunked send it */        if (size > 0) {            flush(true);        }         /* send a zero length chunk */        flush(true);         /* don't close the underlying stream */        out = null;    }     @Override    public synchronized void flush() {        ensureOpen();        if (size > 0) {            flush(true);        }    }}