httpcore5-h2/src/main/java/org/apache/hc/core5/http2/hpack/HPackDecoder.java - httpcomponents-core - Git at Google

 /*
  * ====================================================================
  * 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
  * <http://www.apache.org/>.
  *
  */

 package org.apache.hc.core5.http2.hpack;

 import java.nio.ByteBuffer;
 import java.nio.CharBuffer;
 import java.nio.charset.CharacterCodingException;
 import java.nio.charset.Charset;
 import java.nio.charset.CharsetDecoder;
 import java.nio.charset.CoderResult;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;

 import org.apache.hc.core5.annotation.Internal;
 import org.apache.hc.core5.http.Header;
 import org.apache.hc.core5.http.message.BasicHeader;
 import org.apache.hc.core5.util.Args;
 import org.apache.hc.core5.util.ByteArrayBuffer;

 /**
  * HPACK decoder.
  *
  * @since 5.0
  */
 @Internal
 public final class HPackDecoder {

     private static final String UNEXPECTED_EOS = "Unexpected end of HPACK data";
     private static final String MAX_LIMIT_EXCEEDED = "Max integer exceeded";

     private final InboundDynamicTable dynamicTable;
     private final ByteArrayBuffer contentBuf;
     private final CharsetDecoder charsetDecoder;
     private CharBuffer tmpBuf;
     private int maxTableSize;
     private int maxListSize;

     HPackDecoder(final InboundDynamicTable dynamicTable, final CharsetDecoder charsetDecoder) {
         this.dynamicTable = dynamicTable != null ? dynamicTable : new InboundDynamicTable();
         this.contentBuf = new ByteArrayBuffer(256);
         this.charsetDecoder = charsetDecoder;
         this.maxTableSize = dynamicTable != null ? dynamicTable.getMaxSize() : Integer.MAX_VALUE;
         this.maxListSize = Integer.MAX_VALUE;
     }

     HPackDecoder(final InboundDynamicTable dynamicTable, final Charset charset) {
         this(dynamicTable, charset != null && !StandardCharsets.US_ASCII.equals(charset) ? charset.newDecoder() : null);
     }

     public HPackDecoder(final Charset charset) {
         this(new InboundDynamicTable(), charset);
     }

     public HPackDecoder(final CharsetDecoder charsetDecoder) {
         this(new InboundDynamicTable(), charsetDecoder);
     }

     static int readByte(final ByteBuffer src) throws HPackException {

         if (!src.hasRemaining()) {
             throw new HPackException(UNEXPECTED_EOS);
         }
         return src.get() & 0xff;
     }

     static int peekByte(final ByteBuffer src) throws HPackException {

         if (!src.hasRemaining()) {
             throw new HPackException(UNEXPECTED_EOS);
         }
         final int pos = src.position();
         final int b = src.get() & 0xff;
         src.position(pos);
         return b;
     }

     static int decodeInt(final ByteBuffer src, final int n) throws HPackException {

         final int nbits = 0xff >>> (8 - n);
         int value = readByte(src) & nbits;
         if (value < nbits) {
             return value;
         }
         int m = 0;
         while (m < 32) {
             final int b = readByte(src);
             if ((b & 0x80) != 0) {
                 value += (b & 0x7f) << m;
                 m += 7;
             } else {
                 if (m == 28 && (b & 0xf8) != 0) {
                     break;
                 }
                 value += b << m;
                 return value;
             }
         }
         throw new HPackException(MAX_LIMIT_EXCEEDED);
     }

     static void decodePlainString(final ByteArrayBuffer buffer, final ByteBuffer src) throws HPackException {
         final int strLen = decodeInt(src, 7);
         final int remaining = src.remaining();
         if (strLen > remaining) {
             throw new HPackException(UNEXPECTED_EOS);
         }
         final int originalLimit = src.limit();
         src.limit(originalLimit - (remaining - strLen));
         buffer.append(src);
         src.limit(originalLimit);
     }

     static void decodeHuffman(final ByteArrayBuffer buffer, final ByteBuffer src) throws HPackException {

         final int strLen = decodeInt(src, 7);
         if (strLen > src.remaining()) {
             throw new HPackException(UNEXPECTED_EOS);
         }
         final int limit = src.limit();
         src.limit(src.position() + strLen);
         Huffman.DECODER.decode(buffer, src);
         src.limit(limit);
     }

     void decodeString(final ByteArrayBuffer buffer, final ByteBuffer src) throws HPackException {

         final int firstByte = peekByte(src);
         if ((firstByte & 0x80) == 0x80) {
             decodeHuffman(buffer, src);
         } else {
             decodePlainString(buffer, src);
         }
     }

     int getTmpBufSize() {
         return tmpBuf == null ? 0 : tmpBuf.capacity();
     }

     private void clearState() {

         if (this.tmpBuf != null) {
             this.tmpBuf.clear();
         }
         if (this.charsetDecoder != null) {
             this.charsetDecoder.reset();
         }
         this.contentBuf.clear();
     }

     private void expandCapacity(final int capacity) {

         final CharBuffer previous = this.tmpBuf;
         this.tmpBuf = CharBuffer.allocate(capacity);
         previous.flip();
         this.tmpBuf.put(previous);
     }

     private void ensureCapacity(final int extra) {

         if (this.tmpBuf == null) {
             this.tmpBuf = CharBuffer.allocate(Math.max(256, extra));
         }
         final int requiredCapacity = this.tmpBuf.position() + extra;
         if (requiredCapacity > this.tmpBuf.capacity()) {
             expandCapacity(requiredCapacity);
         }
     }

     int decodeString(final ByteBuffer src, final StringBuilder buf) throws HPackException, CharacterCodingException {

         clearState();
         decodeString(this.contentBuf, src);
         final int binaryLen = this.contentBuf.length();
         if (binaryLen == 0) {
             return 0;
         }
         if (this.charsetDecoder == null) {
             buf.ensureCapacity(binaryLen);
             for (int i = 0; i < binaryLen; i++) {
                 buf.append((char) (this.contentBuf.byteAt(i) & 0xff));
             }
         } else {
             final ByteBuffer in = ByteBuffer.wrap(this.contentBuf.array(), 0, binaryLen);
             while (in.hasRemaining()) {
                 ensureCapacity(in.remaining());
                 final CoderResult result = this.charsetDecoder.decode(in, this.tmpBuf, true);
                 if (result.isError()) {
                     result.throwException();
                 }
             }
             ensureCapacity(8);
             final CoderResult result = this.charsetDecoder.flush(this.tmpBuf);
             if (result.isError()) {
                 result.throwException();
             }
             this.tmpBuf.flip();
             buf.append(this.tmpBuf);
         }
         return binaryLen;
     }

     HPackHeader decodeLiteralHeader(
             final ByteBuffer src,
             final HPackRepresentation representation) throws HPackException, CharacterCodingException {

         final int n = representation == HPackRepresentation.WITH_INDEXING ? 6 : 4;
         final int index = decodeInt(src, n);
         final String name;
         final int nameLen;
         if (index == 0) {
             final StringBuilder buf = new StringBuilder();
             nameLen = decodeString(src, buf);
             name = buf.toString();
         } else {
             final HPackHeader existing =  this.dynamicTable.getHeader(index);
             if (existing == null) {
                 throw new HPackException("Invalid header index");
             }
             name = existing.getName();
             nameLen = existing.getNameLen();
         }
         final StringBuilder buf = new StringBuilder();
         final int valueLen = decodeString(src, buf);
         final String value = buf.toString();
         final HPackHeader header = new HPackHeader(name, nameLen, value, valueLen, representation == HPackRepresentation.NEVER_INDEXED);
         if (representation == HPackRepresentation.WITH_INDEXING) {
             this.dynamicTable.add(header);
         }
         return header;
     }

     HPackHeader decodeIndexedHeader(final ByteBuffer src) throws HPackException {

         final int index = decodeInt(src, 7);
         final HPackHeader existing =  this.dynamicTable.getHeader(index);
         if (existing == null) {
             throw new HPackException("Invalid header index");
         }
         return existing;
     }

     public Header decodeHeader(final ByteBuffer src) throws HPackException {
         final HPackHeader header = decodeHPackHeader(src);
         return header != null ? new BasicHeader(header.getName(), header.getValue(), header.isSensitive()) : null;
     }

     HPackHeader decodeHPackHeader(final ByteBuffer src) throws HPackException {
         try {
             while (src.hasRemaining()) {
                 final int b = peekByte(src);
                 if ((b & 0x80) == 0x80) {
                     return decodeIndexedHeader(src);
                 } else if ((b & 0xc0) == 0x40) {
                     return decodeLiteralHeader(src, HPackRepresentation.WITH_INDEXING);
                 } else if ((b & 0xf0) == 0x00) {
                     return decodeLiteralHeader(src, HPackRepresentation.WITHOUT_INDEXING);
                 } else if ((b & 0xf0) == 0x10) {
                     return decodeLiteralHeader(src, HPackRepresentation.NEVER_INDEXED);
                 } else if ((b & 0xe0) == 0x20) {
                     final int maxSize = decodeInt(src, 5);
                     this.dynamicTable.setMaxSize(Math.min(this.maxTableSize, maxSize));
                 } else {
                     throw new HPackException("Unexpected header first byte: 0x" + Integer.toHexString(b));
                 }
             }
             return null;
         } catch (final CharacterCodingException ex) {
             throw new HPackException(ex.getMessage(), ex);
         }
     }

     public List<Header> decodeHeaders(final ByteBuffer src) throws HPackException {
         final boolean enforceSizeLimit = maxListSize < Integer.MAX_VALUE;
         int listSize = 0;

         final List<Header> list = new ArrayList<>();
         while (src.hasRemaining()) {
             final HPackHeader header = decodeHPackHeader(src);
             if (header == null) {
                 break;
             }
             if (enforceSizeLimit) {
                 listSize += header.getTotalSize();
                 if (listSize >= maxListSize) {
                     throw new HeaderListConstraintException("Maximum header list size exceeded");
                 }
             }
             list.add(new BasicHeader(header.getName(), header.getValue(), header.isSensitive()));
         }
         return list;
     }

     public int getMaxTableSize() {
         return this.maxTableSize;
     }

     public void setMaxTableSize(final int maxTableSize) {
         Args.notNegative(maxTableSize, "Max table size");
         this.maxTableSize = maxTableSize;
         this.dynamicTable.setMaxSize(maxTableSize);
     }

     public int getMaxListSize() {
         return maxListSize;
     }

     public void setMaxListSize(final int maxListSize) {
         Args.notNegative(maxListSize, "Max list size");
         this.maxListSize = maxListSize;
     }

 }
	/*
	* ====================================================================
	* 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
	* <http://www.apache.org/>.
	*
	*/

	package org.apache.hc.core5.http2.hpack;

	import java.nio.ByteBuffer;
	import java.nio.CharBuffer;
	import java.nio.charset.CharacterCodingException;
	import java.nio.charset.Charset;
	import java.nio.charset.CharsetDecoder;
	import java.nio.charset.CoderResult;
	import java.nio.charset.StandardCharsets;
	import java.util.ArrayList;
	import java.util.List;

	import org.apache.hc.core5.annotation.Internal;
	import org.apache.hc.core5.http.Header;
	import org.apache.hc.core5.http.message.BasicHeader;
	import org.apache.hc.core5.util.Args;
	import org.apache.hc.core5.util.ByteArrayBuffer;

	/**
	* HPACK decoder.
	*
	* @since 5.0
	*/
	@Internal
	public final class HPackDecoder {

	private static final String UNEXPECTED_EOS = "Unexpected end of HPACK data";
	private static final String MAX_LIMIT_EXCEEDED = "Max integer exceeded";

	private final InboundDynamicTable dynamicTable;
	private final ByteArrayBuffer contentBuf;
	private final CharsetDecoder charsetDecoder;
	private CharBuffer tmpBuf;
	private int maxTableSize;
	private int maxListSize;

	HPackDecoder(final InboundDynamicTable dynamicTable, final CharsetDecoder charsetDecoder) {
	this.dynamicTable = dynamicTable != null ? dynamicTable : new InboundDynamicTable();
	this.contentBuf = new ByteArrayBuffer(256);
	this.charsetDecoder = charsetDecoder;
	this.maxTableSize = dynamicTable != null ? dynamicTable.getMaxSize() : Integer.MAX_VALUE;
	this.maxListSize = Integer.MAX_VALUE;
	}

	HPackDecoder(final InboundDynamicTable dynamicTable, final Charset charset) {
	this(dynamicTable, charset != null && !StandardCharsets.US_ASCII.equals(charset) ? charset.newDecoder() : null);
	}

	public HPackDecoder(final Charset charset) {
	this(new InboundDynamicTable(), charset);
	}

	public HPackDecoder(final CharsetDecoder charsetDecoder) {
	this(new InboundDynamicTable(), charsetDecoder);
	}

	static int readByte(final ByteBuffer src) throws HPackException {

	if (!src.hasRemaining()) {
	throw new HPackException(UNEXPECTED_EOS);
	}
	return src.get() & 0xff;
	}

	static int peekByte(final ByteBuffer src) throws HPackException {

	if (!src.hasRemaining()) {
	throw new HPackException(UNEXPECTED_EOS);
	}
	final int pos = src.position();
	final int b = src.get() & 0xff;
	src.position(pos);
	return b;
	}

	static int decodeInt(final ByteBuffer src, final int n) throws HPackException {

	final int nbits = 0xff >>> (8 - n);
	int value = readByte(src) & nbits;
	if (value < nbits) {
	return value;
	}
	int m = 0;
	while (m < 32) {
	final int b = readByte(src);
	if ((b & 0x80) != 0) {
	value += (b & 0x7f) << m;
	m += 7;
	} else {
	if (m == 28 && (b & 0xf8) != 0) {
	break;
	}
	value += b << m;
	return value;
	}
	}
	throw new HPackException(MAX_LIMIT_EXCEEDED);
	}

	static void decodePlainString(final ByteArrayBuffer buffer, final ByteBuffer src) throws HPackException {
	final int strLen = decodeInt(src, 7);
	final int remaining = src.remaining();
	if (strLen > remaining) {
	throw new HPackException(UNEXPECTED_EOS);
	}
	final int originalLimit = src.limit();
	src.limit(originalLimit - (remaining - strLen));
	buffer.append(src);
	src.limit(originalLimit);
	}

	static void decodeHuffman(final ByteArrayBuffer buffer, final ByteBuffer src) throws HPackException {

	final int strLen = decodeInt(src, 7);
	if (strLen > src.remaining()) {
	throw new HPackException(UNEXPECTED_EOS);
	}
	final int limit = src.limit();
	src.limit(src.position() + strLen);
	Huffman.DECODER.decode(buffer, src);
	src.limit(limit);
	}

	void decodeString(final ByteArrayBuffer buffer, final ByteBuffer src) throws HPackException {

	final int firstByte = peekByte(src);
	if ((firstByte & 0x80) == 0x80) {
	decodeHuffman(buffer, src);
	} else {
	decodePlainString(buffer, src);
	}
	}

	int getTmpBufSize() {
	return tmpBuf == null ? 0 : tmpBuf.capacity();
	}

	private void clearState() {

	if (this.tmpBuf != null) {
	this.tmpBuf.clear();
	}
	if (this.charsetDecoder != null) {
	this.charsetDecoder.reset();
	}
	this.contentBuf.clear();
	}

	private void expandCapacity(final int capacity) {

	final CharBuffer previous = this.tmpBuf;
	this.tmpBuf = CharBuffer.allocate(capacity);
	previous.flip();
	this.tmpBuf.put(previous);
	}

	private void ensureCapacity(final int extra) {

	if (this.tmpBuf == null) {
	this.tmpBuf = CharBuffer.allocate(Math.max(256, extra));
	}
	final int requiredCapacity = this.tmpBuf.position() + extra;
	if (requiredCapacity > this.tmpBuf.capacity()) {
	expandCapacity(requiredCapacity);
	}
	}

	int decodeString(final ByteBuffer src, final StringBuilder buf) throws HPackException, CharacterCodingException {

	clearState();
	decodeString(this.contentBuf, src);
	final int binaryLen = this.contentBuf.length();
	if (binaryLen == 0) {
	return 0;
	}
	if (this.charsetDecoder == null) {
	buf.ensureCapacity(binaryLen);
	for (int i = 0; i < binaryLen; i++) {
	buf.append((char) (this.contentBuf.byteAt(i) & 0xff));
	}
	} else {
	final ByteBuffer in = ByteBuffer.wrap(this.contentBuf.array(), 0, binaryLen);
	while (in.hasRemaining()) {
	ensureCapacity(in.remaining());
	final CoderResult result = this.charsetDecoder.decode(in, this.tmpBuf, true);
	if (result.isError()) {
	result.throwException();
	}
	}
	ensureCapacity(8);
	final CoderResult result = this.charsetDecoder.flush(this.tmpBuf);
	if (result.isError()) {
	result.throwException();
	}
	this.tmpBuf.flip();
	buf.append(this.tmpBuf);
	}
	return binaryLen;
	}

	HPackHeader decodeLiteralHeader(
	final ByteBuffer src,
	final HPackRepresentation representation) throws HPackException, CharacterCodingException {

	final int n = representation == HPackRepresentation.WITH_INDEXING ? 6 : 4;
	final int index = decodeInt(src, n);
	final String name;
	final int nameLen;
	if (index == 0) {
	final StringBuilder buf = new StringBuilder();
	nameLen = decodeString(src, buf);
	name = buf.toString();
	} else {
	final HPackHeader existing = this.dynamicTable.getHeader(index);
	if (existing == null) {
	throw new HPackException("Invalid header index");
	}
	name = existing.getName();
	nameLen = existing.getNameLen();
	}
	final StringBuilder buf = new StringBuilder();
	final int valueLen = decodeString(src, buf);
	final String value = buf.toString();
	final HPackHeader header = new HPackHeader(name, nameLen, value, valueLen, representation == HPackRepresentation.NEVER_INDEXED);
	if (representation == HPackRepresentation.WITH_INDEXING) {
	this.dynamicTable.add(header);
	}
	return header;
	}

	HPackHeader decodeIndexedHeader(final ByteBuffer src) throws HPackException {

	final int index = decodeInt(src, 7);
	final HPackHeader existing = this.dynamicTable.getHeader(index);
	if (existing == null) {
	throw new HPackException("Invalid header index");
	}
	return existing;
	}

	public Header decodeHeader(final ByteBuffer src) throws HPackException {
	final HPackHeader header = decodeHPackHeader(src);
	return header != null ? new BasicHeader(header.getName(), header.getValue(), header.isSensitive()) : null;
	}

	HPackHeader decodeHPackHeader(final ByteBuffer src) throws HPackException {
	try {
	while (src.hasRemaining()) {
	final int b = peekByte(src);
	if ((b & 0x80) == 0x80) {
	return decodeIndexedHeader(src);
	} else if ((b & 0xc0) == 0x40) {
	return decodeLiteralHeader(src, HPackRepresentation.WITH_INDEXING);
	} else if ((b & 0xf0) == 0x00) {
	return decodeLiteralHeader(src, HPackRepresentation.WITHOUT_INDEXING);
	} else if ((b & 0xf0) == 0x10) {
	return decodeLiteralHeader(src, HPackRepresentation.NEVER_INDEXED);
	} else if ((b & 0xe0) == 0x20) {
	final int maxSize = decodeInt(src, 5);
	this.dynamicTable.setMaxSize(Math.min(this.maxTableSize, maxSize));
	} else {
	throw new HPackException("Unexpected header first byte: 0x" + Integer.toHexString(b));
	}
	}
	return null;
	} catch (final CharacterCodingException ex) {
	throw new HPackException(ex.getMessage(), ex);
	}
	}

	public List<Header> decodeHeaders(final ByteBuffer src) throws HPackException {
	final boolean enforceSizeLimit = maxListSize < Integer.MAX_VALUE;
	int listSize = 0;

	final List<Header> list = new ArrayList<>();
	while (src.hasRemaining()) {
	final HPackHeader header = decodeHPackHeader(src);
	if (header == null) {
	break;
	}
	if (enforceSizeLimit) {
	listSize += header.getTotalSize();
	if (listSize >= maxListSize) {
	throw new HeaderListConstraintException("Maximum header list size exceeded");
	}
	}
	list.add(new BasicHeader(header.getName(), header.getValue(), header.isSensitive()));
	}
	return list;
	}

	public int getMaxTableSize() {
	return this.maxTableSize;
	}

	public void setMaxTableSize(final int maxTableSize) {
	Args.notNegative(maxTableSize, "Max table size");
	this.maxTableSize = maxTableSize;
	this.dynamicTable.setMaxSize(maxTableSize);
	}

	public int getMaxListSize() {
	return maxListSize;
	}

	public void setMaxListSize(final int maxListSize) {
	Args.notNegative(maxListSize, "Max list size");
	this.maxListSize = maxListSize;
	}

	}