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:  * Output stream that cuts off after a defined number of bytes. This class
michael@0:  * is used to send content of HTTP messages where the end of the content entity
michael@0:  * is determined by the value of the <code>Content-Length header</code>.
michael@0:  * Entities transferred using this stream can be maximum {@link Long#MAX_VALUE}
michael@0:  * long.
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:  * @since 4.0
michael@0:  */
michael@0: public class ContentLengthOutputStream extends OutputStream {
michael@0: 
michael@0:     /**
michael@0:      * Wrapped session output buffer.
michael@0:      */
michael@0:     private final SessionOutputBuffer out;
michael@0: 
michael@0:     /**
michael@0:      * The maximum number of bytes that can be written the stream. Subsequent
michael@0:      * write operations will be ignored.
michael@0:      */
michael@0:     private final long contentLength;
michael@0: 
michael@0:     /** Total bytes written */
michael@0:     private long total = 0;
michael@0: 
michael@0:     /** True if the stream is closed. */
michael@0:     private boolean closed = false;
michael@0: 
michael@0:     /**
michael@0:      * Wraps a session output buffer and cuts off output after a defined number
michael@0:      * of bytes.
michael@0:      *
michael@0:      * @param out The session output buffer
michael@0:      * @param contentLength The maximum number of bytes that can be written to
michael@0:      * the stream. Subsequent write operations will be ignored.
michael@0:      *
michael@0:      * @since 4.0
michael@0:      */
michael@0:     public ContentLengthOutputStream(final SessionOutputBuffer out, long contentLength) {
michael@0:         super();
michael@0:         if (out == null) {
michael@0:             throw new IllegalArgumentException("Session output buffer may not be null");
michael@0:         }
michael@0:         if (contentLength < 0) {
michael@0:             throw new IllegalArgumentException("Content length may not be negative");
michael@0:         }
michael@0:         this.out = out;
michael@0:         this.contentLength = contentLength;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * <p>Does not close the underlying socket output.</p>
michael@0:      *
michael@0:      * @throws IOException If an I/O problem occurs.
michael@0:      */
michael@0:     public void close() throws IOException {
michael@0:         if (!this.closed) {
michael@0:             this.closed = true;
michael@0:             this.out.flush();
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     public void flush() throws IOException {
michael@0:         this.out.flush();
michael@0:     }
michael@0: 
michael@0:     public void write(byte[] b, 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 (this.total < this.contentLength) {
michael@0:             long max = this.contentLength - this.total;
michael@0:             if (len > max) {
michael@0:                 len = (int) max;
michael@0:             }
michael@0:             this.out.write(b, off, len);
michael@0:             this.total += len;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     public void write(byte[] b) throws IOException {
michael@0:         write(b, 0, b.length);
michael@0:     }
michael@0: 
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:         if (this.total < this.contentLength) {
michael@0:             this.out.write(b);
michael@0:             this.total++;
michael@0:         }
michael@0:     }
michael@0: 
michael@0: }