michael@0: /*
michael@0:  * ====================================================================
michael@0:  * Licensed to the Apache Software Foundation (ASF) under one
michael@0:  * or more contributor license agreements.  See the NOTICE file
michael@0:  * distributed with this work for additional information
michael@0:  * regarding copyright ownership.  The ASF licenses this file
michael@0:  * to you under the Apache License, Version 2.0 (the
michael@0:  * "License"); you may not use this file except in compliance
michael@0:  * with the License.  You may obtain a copy of the License at
michael@0:  *
michael@0:  *   http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  * Unless required by applicable law or agreed to in writing,
michael@0:  * software distributed under the License is distributed on an
michael@0:  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
michael@0:  * KIND, either express or implied.  See the License for the
michael@0:  * specific language governing permissions and limitations
michael@0:  * under the License.
michael@0:  * ====================================================================
michael@0:  *
michael@0:  * This software consists of voluntary contributions made by many
michael@0:  * individuals on behalf of the Apache Software Foundation.  For more
michael@0:  * information on the Apache Software Foundation, please see
michael@0:  * <http://www.apache.org/>.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: package ch.boye.httpclientandroidlib.impl.io;
michael@0: 
michael@0: import java.io.IOException;
michael@0: import java.io.OutputStream;
michael@0: 
michael@0: import ch.boye.httpclientandroidlib.io.SessionOutputBuffer;
michael@0: 
michael@0: /**
michael@0:  * Implements chunked transfer coding. The content is sent in small chunks.
michael@0:  * Entities transferred using this output stream can be of unlimited length.
michael@0:  * Writes are buffered to an internal buffer (2048 default size).
michael@0:  * <p>
michael@0:  * Note that this class NEVER closes the underlying stream, even when close
michael@0:  * gets called.  Instead, the stream will be marked as closed and no further
michael@0:  * output will be permitted.
michael@0:  *
michael@0:  *
michael@0:  * @since 4.0
michael@0:  */
michael@0: public class ChunkedOutputStream extends OutputStream {
michael@0: 
michael@0:     // ----------------------------------------------------- Instance Variables
michael@0:     private final SessionOutputBuffer out;
michael@0: 
michael@0:     private byte[] cache;
michael@0: 
michael@0:     private int cachePosition = 0;
michael@0: 
michael@0:     private boolean wroteLastChunk = false;
michael@0: 
michael@0:     /** True if the stream is closed. */
michael@0:     private boolean closed = false;
michael@0: 
michael@0:     // ----------------------------------------------------------- Constructors
michael@0:     /**
michael@0:      * Wraps a session output buffer and chunk-encodes the output.
michael@0:      *
michael@0:      * @param out The session output buffer
michael@0:      * @param bufferSize The minimum chunk size (excluding last chunk)
michael@0:      * @throws IOException in case of an I/O error
michael@0:      */
michael@0:     public ChunkedOutputStream(final SessionOutputBuffer out, int bufferSize)
michael@0:             throws IOException {
michael@0:         super();
michael@0:         this.cache = new byte[bufferSize];
michael@0:         this.out = out;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Wraps a session output buffer and chunks the output. The default buffer
michael@0:      * size of 2048 was chosen because the chunk overhead is less than 0.5%
michael@0:      *
michael@0:      * @param out       the output buffer to wrap
michael@0:      * @throws IOException in case of an I/O error
michael@0:      */
michael@0:     public ChunkedOutputStream(final SessionOutputBuffer out)
michael@0:             throws IOException {
michael@0:         this(out, 2048);
michael@0:     }
michael@0: 
michael@0:     // ----------------------------------------------------------- Internal methods
michael@0:     /**
michael@0:      * Writes the cache out onto the underlying stream
michael@0:      */
michael@0:     protected void flushCache() throws IOException {
michael@0:         if (this.cachePosition > 0) {
michael@0:             this.out.writeLine(Integer.toHexString(this.cachePosition));
michael@0:             this.out.write(this.cache, 0, this.cachePosition);
michael@0:             this.out.writeLine("");
michael@0:             this.cachePosition = 0;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Writes the cache and bufferToAppend to the underlying stream
michael@0:      * as one large chunk
michael@0:      */
michael@0:     protected void flushCacheWithAppend(byte bufferToAppend[], int off, int len) throws IOException {
michael@0:         this.out.writeLine(Integer.toHexString(this.cachePosition + len));
michael@0:         this.out.write(this.cache, 0, this.cachePosition);
michael@0:         this.out.write(bufferToAppend, off, len);
michael@0:         this.out.writeLine("");
michael@0:         this.cachePosition = 0;
michael@0:     }
michael@0: 
michael@0:     protected void writeClosingChunk() throws IOException {
michael@0:         // Write the final chunk.
michael@0:         this.out.writeLine("0");
michael@0:         this.out.writeLine("");
michael@0:     }
michael@0: 
michael@0:     // ----------------------------------------------------------- Public Methods
michael@0:     /**
michael@0:      * Must be called to ensure the internal cache is flushed and the closing
michael@0:      * chunk is written.
michael@0:      * @throws IOException in case of an I/O error
michael@0:      */
michael@0:     public void finish() throws IOException {
michael@0:         if (!this.wroteLastChunk) {
michael@0:             flushCache();
michael@0:             writeClosingChunk();
michael@0:             this.wroteLastChunk = true;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // -------------------------------------------- OutputStream Methods
michael@0:     public void write(int b) throws IOException {
michael@0:         if (this.closed) {
michael@0:             throw new IOException("Attempted write to closed stream.");
michael@0:         }
michael@0:         this.cache[this.cachePosition] = (byte) b;
michael@0:         this.cachePosition++;
michael@0:         if (this.cachePosition == this.cache.length) flushCache();
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Writes the array. If the array does not fit within the buffer, it is
michael@0:      * not split, but rather written out as one large chunk.
michael@0:      */
michael@0:     public void write(byte b[]) throws IOException {
michael@0:         write(b, 0, b.length);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Writes the array. If the array does not fit within the buffer, it is
michael@0:      * not split, but rather written out as one large chunk.
michael@0:      */
michael@0:     public void write(byte src[], int off, int len) throws IOException {
michael@0:         if (this.closed) {
michael@0:             throw new IOException("Attempted write to closed stream.");
michael@0:         }
michael@0:         if (len >= this.cache.length - this.cachePosition) {
michael@0:             flushCacheWithAppend(src, off, len);
michael@0:         } else {
michael@0:             System.arraycopy(src, off, cache, this.cachePosition, len);
michael@0:             this.cachePosition += len;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Flushes the content buffer and the underlying stream.
michael@0:      */
michael@0:     public void flush() throws IOException {
michael@0:         flushCache();
michael@0:         this.out.flush();
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Finishes writing to the underlying stream, but does NOT close the underlying stream.
michael@0:      */
michael@0:     public void close() throws IOException {
michael@0:         if (!this.closed) {
michael@0:             this.closed = true;
michael@0:             finish();
michael@0:             this.out.flush();
michael@0:         }
michael@0:     }
michael@0: }