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/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * .
 *
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package org.apache.http.impl.io;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CoderResult;

import org.apache.http.MessageConstraintException;
import org.apache.http.annotation.NotThreadSafe;
import org.apache.http.config.MessageConstraints;
import org.apache.http.io.BufferInfo;
import org.apache.http.io.HttpTransportMetrics;
import org.apache.http.io.SessionInputBuffer;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.Args;
import org.apache.http.util.Asserts;
import org.apache.http.util.ByteArrayBuffer;
import org.apache.http.util.CharArrayBuffer;

/**
 * Abstract base class for session input buffers that stream data from
 * an arbitrary {@link InputStream}. This class buffers input data in
 * an internal byte array for optimal input performance.
 * 

* {@link #readLine(CharArrayBuffer)} and {@link #readLine()} methods of this * class treat a lone LF as valid line delimiters in addition to CR-LF required * by the HTTP specification. * * @since 4.3 */ @NotThreadSafe public class SessionInputBufferImpl implements SessionInputBuffer, BufferInfo { private final HttpTransportMetricsImpl metrics; private final byte[] buffer; private final ByteArrayBuffer linebuffer; private final int minChunkLimit; private final MessageConstraints constraints; private final CharsetDecoder decoder; private InputStream instream; private int bufferpos; private int bufferlen; private CharBuffer cbuf; /** * Creates new instance of SessionInputBufferImpl. * * @param metrics HTTP transport metrics. * @param buffersize buffer size. Must be a positive number. * @param minChunkLimit size limit below which data chunks should be buffered in memory * in order to minimize native method invocations on the underlying network socket. * The optimal value of this parameter can be platform specific and defines a trade-off * between performance of memory copy operations and that of native method invocation. * If negative default chunk limited will be used. * @param constraints Message constraints. If {@code null} * {@link MessageConstraints#DEFAULT} will be used. * @param chardecoder chardecoder to be used for decoding HTTP protocol elements. * If {@code null} simple type cast will be used for byte to char conversion. */ public SessionInputBufferImpl( final HttpTransportMetricsImpl metrics, final int buffersize, final int minChunkLimit, final MessageConstraints constraints, final CharsetDecoder chardecoder) { Args.notNull(metrics, "HTTP transport metrcis"); Args.positive(buffersize, "Buffer size"); this.metrics = metrics; this.buffer = new byte[buffersize]; this.bufferpos = 0; this.bufferlen = 0; this.minChunkLimit = minChunkLimit >= 0 ? minChunkLimit : 512; this.constraints = constraints != null ? constraints : MessageConstraints.DEFAULT; this.linebuffer = new ByteArrayBuffer(buffersize); this.decoder = chardecoder; } public SessionInputBufferImpl( final HttpTransportMetricsImpl metrics, final int buffersize) { this(metrics, buffersize, buffersize, null, null); } public void bind(final InputStream instream) { this.instream = instream; } public boolean isBound() { return this.instream != null; } @Override public int capacity() { return this.buffer.length; } @Override public int length() { return this.bufferlen - this.bufferpos; } @Override public int available() { return capacity() - length(); } private int streamRead(final byte[] b, final int off, final int len) throws IOException { Asserts.notNull(this.instream, "Input stream"); return this.instream.read(b, off, len); } public int fillBuffer() throws IOException { // compact the buffer if necessary if (this.bufferpos > 0) { final int len = this.bufferlen - this.bufferpos; if (len > 0) { System.arraycopy(this.buffer, this.bufferpos, this.buffer, 0, len); } this.bufferpos = 0; this.bufferlen = len; } final int l; final int off = this.bufferlen; final int len = this.buffer.length - off; l = streamRead(this.buffer, off, len); if (l == -1) { return -1; } else { this.bufferlen = off + l; this.metrics.incrementBytesTransferred(l); return l; } } public boolean hasBufferedData() { return this.bufferpos < this.bufferlen; } public void clear() { this.bufferpos = 0; this.bufferlen = 0; } @Override public int read() throws IOException { int noRead; while (!hasBufferedData()) { noRead = fillBuffer(); if (noRead == -1) { return -1; } } return this.buffer[this.bufferpos++] & 0xff; } @Override public int read(final byte[] b, final int off, final int len) throws IOException { if (b == null) { return 0; } if (hasBufferedData()) { final int chunk = Math.min(len, this.bufferlen - this.bufferpos); System.arraycopy(this.buffer, this.bufferpos, b, off, chunk); this.bufferpos += chunk; return chunk; } // If the remaining capacity is big enough, read directly from the // underlying input stream bypassing the buffer. if (len > this.minChunkLimit) { final int read = streamRead(b, off, len); if (read > 0) { this.metrics.incrementBytesTransferred(read); } return read; } else { // otherwise read to the buffer first while (!hasBufferedData()) { final int noRead = fillBuffer(); if (noRead == -1) { return -1; } } final int chunk = Math.min(len, this.bufferlen - this.bufferpos); System.arraycopy(this.buffer, this.bufferpos, b, off, chunk); this.bufferpos += chunk; return chunk; } } @Override public int read(final byte[] b) throws IOException { if (b == null) { return 0; } return read(b, 0, b.length); } /** * Reads a complete line of characters up to a line delimiter from this * session buffer into the given line buffer. The number of chars actually * read is returned as an integer. The line delimiter itself is discarded. * If no char is available because the end of the stream has been reached, * the value {@code -1} is returned. This method blocks until input * data is available, end of file is detected, or an exception is thrown. *

* This method treats a lone LF as a valid line delimiters in addition * to CR-LF required by the HTTP specification. * * @param charbuffer the line buffer. * @return one line of characters * @exception IOException if an I/O error occurs. */ @Override public int readLine(final CharArrayBuffer charbuffer) throws IOException { Args.notNull(charbuffer, "Char array buffer"); final int maxLineLen = this.constraints.getMaxLineLength(); int noRead = 0; boolean retry = true; while (retry) { // attempt to find end of line (LF) int pos = -1; for (int i = this.bufferpos; i < this.bufferlen; i++) { if (this.buffer[i] == HTTP.LF) { pos = i; break; } } if (maxLineLen > 0) { final int currentLen = this.linebuffer.length() + (pos > 0 ? pos : this.bufferlen) - this.bufferpos; if (currentLen >= maxLineLen) { throw new MessageConstraintException("Maximum line length limit exceeded"); } } if (pos != -1) { // end of line found. if (this.linebuffer.isEmpty()) { // the entire line is preset in the read buffer return lineFromReadBuffer(charbuffer, pos); } retry = false; final int len = pos + 1 - this.bufferpos; this.linebuffer.append(this.buffer, this.bufferpos, len); this.bufferpos = pos + 1; } else { // end of line not found if (hasBufferedData()) { final int len = this.bufferlen - this.bufferpos; this.linebuffer.append(this.buffer, this.bufferpos, len); this.bufferpos = this.bufferlen; } noRead = fillBuffer(); if (noRead == -1) { retry = false; } } } if (noRead == -1 && this.linebuffer.isEmpty()) { // indicate the end of stream return -1; } return lineFromLineBuffer(charbuffer); } /** * Reads a complete line of characters up to a line delimiter from this * session buffer. The line delimiter itself is discarded. If no char is * available because the end of the stream has been reached, * {@code null} is returned. This method blocks until input data is * available, end of file is detected, or an exception is thrown. *

* This method treats a lone LF as a valid line delimiters in addition * to CR-LF required by the HTTP specification. * * @return HTTP line as a string * @exception IOException if an I/O error occurs. */ private int lineFromLineBuffer(final CharArrayBuffer charbuffer) throws IOException { // discard LF if found int len = this.linebuffer.length(); if (len > 0) { if (this.linebuffer.byteAt(len - 1) == HTTP.LF) { len--; } // discard CR if found if (len > 0) { if (this.linebuffer.byteAt(len - 1) == HTTP.CR) { len--; } } } if (this.decoder == null) { charbuffer.append(this.linebuffer, 0, len); } else { final ByteBuffer bbuf = ByteBuffer.wrap(this.linebuffer.buffer(), 0, len); len = appendDecoded(charbuffer, bbuf); } this.linebuffer.clear(); return len; } private int lineFromReadBuffer(final CharArrayBuffer charbuffer, final int position) throws IOException { int pos = position; final int off = this.bufferpos; int len; this.bufferpos = pos + 1; if (pos > off && this.buffer[pos - 1] == HTTP.CR) { // skip CR if found pos--; } len = pos - off; if (this.decoder == null) { charbuffer.append(this.buffer, off, len); } else { final ByteBuffer bbuf = ByteBuffer.wrap(this.buffer, off, len); len = appendDecoded(charbuffer, bbuf); } return len; } private int appendDecoded( final CharArrayBuffer charbuffer, final ByteBuffer bbuf) throws IOException { if (!bbuf.hasRemaining()) { return 0; } if (this.cbuf == null) { this.cbuf = CharBuffer.allocate(1024); } this.decoder.reset(); int len = 0; while (bbuf.hasRemaining()) { final CoderResult result = this.decoder.decode(bbuf, this.cbuf, true); len += handleDecodingResult(result, charbuffer, bbuf); } final CoderResult result = this.decoder.flush(this.cbuf); len += handleDecodingResult(result, charbuffer, bbuf); this.cbuf.clear(); return len; } private int handleDecodingResult( final CoderResult result, final CharArrayBuffer charbuffer, final ByteBuffer bbuf) throws IOException { if (result.isError()) { result.throwException(); } this.cbuf.flip(); final int len = this.cbuf.remaining(); while (this.cbuf.hasRemaining()) { charbuffer.append(this.cbuf.get()); } this.cbuf.compact(); return len; } @Override public String readLine() throws IOException { final CharArrayBuffer charbuffer = new CharArrayBuffer(64); final int l = readLine(charbuffer); if (l != -1) { return charbuffer.toString(); } else { return null; } } @Override public boolean isDataAvailable(final int timeout) throws IOException { return hasBufferedData(); } @Override public HttpTransportMetrics getMetrics() { return this.metrics; } }





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