Motivation: A degradation in performance has been observed from the 4.0 branch as documented in https://github.com/netty/netty/issues/3962. Modifications: - Simplify Headers class hierarchy. - Restore the DefaultHeaders to be based upon DefaultHttpHeaders from 4.0. - Make various other modifications that are causing hot spots. Result: Performance is now on par with 4.0.
168 lines
6.2 KiB
Java
168 lines
6.2 KiB
Java
/*
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* Copyright 2012 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.handler.codec.http;
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import io.netty.channel.embedded.EmbeddedChannel;
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import io.netty.handler.codec.compression.ZlibCodecFactory;
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import io.netty.handler.codec.compression.ZlibWrapper;
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import io.netty.util.internal.StringUtil;
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/**
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* Compresses an {@link HttpMessage} and an {@link HttpContent} in {@code gzip} or
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* {@code deflate} encoding while respecting the {@code "Accept-Encoding"} header.
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* If there is no matching encoding, no compression is done. For more
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* information on how this handler modifies the message, please refer to
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* {@link HttpContentEncoder}.
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*/
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public class HttpContentCompressor extends HttpContentEncoder {
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private final int compressionLevel;
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private final int windowBits;
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private final int memLevel;
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/**
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* Creates a new handler with the default compression level (<tt>6</tt>),
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* default window size (<tt>15</tt>) and default memory level (<tt>8</tt>).
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*/
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public HttpContentCompressor() {
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this(6);
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}
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/**
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* Creates a new handler with the specified compression level, default
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* window size (<tt>15</tt>) and default memory level (<tt>8</tt>).
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*
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* @param compressionLevel
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* {@code 1} yields the fastest compression and {@code 9} yields the
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* best compression. {@code 0} means no compression. The default
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* compression level is {@code 6}.
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*/
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public HttpContentCompressor(int compressionLevel) {
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this(compressionLevel, 15, 8);
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}
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/**
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* Creates a new handler with the specified compression level, window size,
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* and memory level..
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*
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* @param compressionLevel
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* {@code 1} yields the fastest compression and {@code 9} yields the
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* best compression. {@code 0} means no compression. The default
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* compression level is {@code 6}.
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* @param windowBits
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* The base two logarithm of the size of the history buffer. The
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* value should be in the range {@code 9} to {@code 15} inclusive.
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* Larger values result in better compression at the expense of
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* memory usage. The default value is {@code 15}.
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* @param memLevel
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* How much memory should be allocated for the internal compression
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* state. {@code 1} uses minimum memory and {@code 9} uses maximum
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* memory. Larger values result in better and faster compression
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* at the expense of memory usage. The default value is {@code 8}
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*/
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public HttpContentCompressor(int compressionLevel, int windowBits, int memLevel) {
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if (compressionLevel < 0 || compressionLevel > 9) {
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throw new IllegalArgumentException(
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"compressionLevel: " + compressionLevel +
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" (expected: 0-9)");
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}
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if (windowBits < 9 || windowBits > 15) {
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throw new IllegalArgumentException(
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"windowBits: " + windowBits + " (expected: 9-15)");
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}
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if (memLevel < 1 || memLevel > 9) {
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throw new IllegalArgumentException(
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"memLevel: " + memLevel + " (expected: 1-9)");
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}
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this.compressionLevel = compressionLevel;
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this.windowBits = windowBits;
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this.memLevel = memLevel;
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}
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@Override
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protected Result beginEncode(HttpResponse headers, String acceptEncoding) throws Exception {
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String contentEncoding = headers.headers().get(HttpHeaderNames.CONTENT_ENCODING);
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if (contentEncoding != null &&
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!HttpHeaderValues.IDENTITY.contentEqualsIgnoreCase(contentEncoding)) {
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return null;
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}
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ZlibWrapper wrapper = determineWrapper(acceptEncoding);
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if (wrapper == null) {
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return null;
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}
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String targetContentEncoding;
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switch (wrapper) {
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case GZIP:
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targetContentEncoding = "gzip";
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break;
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case ZLIB:
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targetContentEncoding = "deflate";
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break;
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default:
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throw new Error();
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}
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return new Result(
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targetContentEncoding,
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new EmbeddedChannel(ZlibCodecFactory.newZlibEncoder(
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wrapper, compressionLevel, windowBits, memLevel)));
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}
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@SuppressWarnings("FloatingPointEquality")
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protected ZlibWrapper determineWrapper(String acceptEncoding) {
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float starQ = -1.0f;
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float gzipQ = -1.0f;
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float deflateQ = -1.0f;
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for (String encoding: StringUtil.split(acceptEncoding, ',')) {
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float q = 1.0f;
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int equalsPos = encoding.indexOf('=');
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if (equalsPos != -1) {
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try {
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q = Float.valueOf(encoding.substring(equalsPos + 1));
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} catch (NumberFormatException e) {
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// Ignore encoding
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q = 0.0f;
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}
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}
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if (encoding.contains("*")) {
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starQ = q;
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} else if (encoding.contains("gzip") && q > gzipQ) {
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gzipQ = q;
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} else if (encoding.contains("deflate") && q > deflateQ) {
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deflateQ = q;
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}
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}
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if (gzipQ > 0.0f || deflateQ > 0.0f) {
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if (gzipQ >= deflateQ) {
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return ZlibWrapper.GZIP;
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} else {
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return ZlibWrapper.ZLIB;
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}
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}
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if (starQ > 0.0f) {
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if (gzipQ == -1.0f) {
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return ZlibWrapper.GZIP;
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}
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if (deflateQ == -1.0f) {
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return ZlibWrapper.ZLIB;
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}
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}
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return null;
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}
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}
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