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16 package io.netty.handler.codec.http.websocketx.extensions.compression;
17
18 import io.netty.buffer.ByteBuf;
19 import io.netty.buffer.CompositeByteBuf;
20 import io.netty.channel.ChannelHandler;
21 import io.netty.channel.ChannelHandlerContext;
22 import io.netty.channel.embedded.EmbeddedChannel;
23 import io.netty.handler.codec.CodecException;
24 import io.netty.handler.codec.compression.ZlibCodecFactory;
25 import io.netty.handler.codec.compression.ZlibWrapper;
26 import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame;
27 import io.netty.handler.codec.http.websocketx.ContinuationWebSocketFrame;
28 import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
29 import io.netty.handler.codec.http.websocketx.WebSocketFrame;
30 import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionEncoder;
31 import io.netty.handler.codec.http.websocketx.extensions.WebSocketExtensionFilter;
32
33 import java.util.List;
34
35 import static io.netty.handler.codec.http.websocketx.extensions.compression.PerMessageDeflateDecoder.*;
36 import static io.netty.util.internal.ObjectUtil.*;
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42 abstract class DeflateEncoder extends WebSocketExtensionEncoder {
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44 static final int DEFAULT_MEM_LEVEL = 8;
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46 private final int compressionLevel;
47 private final int windowSize;
48 private final int memLevel;
49 private final boolean noContext;
50 private final WebSocketExtensionFilter extensionEncoderFilter;
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52 private EmbeddedChannel encoder;
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61 DeflateEncoder(int compressionLevel, int windowSize, boolean noContext,
62 WebSocketExtensionFilter extensionEncoderFilter) {
63 this(compressionLevel, windowSize, DEFAULT_MEM_LEVEL, noContext, extensionEncoderFilter);
64 }
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74 DeflateEncoder(int compressionLevel, int windowSize, int memLevel, boolean noContext,
75 WebSocketExtensionFilter extensionEncoderFilter) {
76 this.compressionLevel = compressionLevel;
77 this.windowSize = windowSize;
78 this.memLevel = memLevel;
79 this.noContext = noContext;
80 this.extensionEncoderFilter = checkNotNull(extensionEncoderFilter, "extensionEncoderFilter");
81 }
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86 protected WebSocketExtensionFilter extensionEncoderFilter() {
87 return extensionEncoderFilter;
88 }
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94 protected abstract int rsv(WebSocketFrame msg);
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100 protected abstract boolean removeFrameTail(WebSocketFrame msg);
101
102 @Override
103 protected void encode(ChannelHandlerContext ctx, WebSocketFrame msg, List<Object> out) throws Exception {
104 final ByteBuf compressedContent;
105 if (msg.content().isReadable()) {
106 compressedContent = compressContent(ctx, msg);
107 } else if (msg.isFinalFragment()) {
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110 compressedContent = EMPTY_DEFLATE_BLOCK.duplicate();
111 } else {
112 throw new CodecException("cannot compress content buffer");
113 }
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115 final WebSocketFrame outMsg;
116 if (msg instanceof TextWebSocketFrame) {
117 outMsg = new TextWebSocketFrame(msg.isFinalFragment(), rsv(msg), compressedContent);
118 } else if (msg instanceof BinaryWebSocketFrame) {
119 outMsg = new BinaryWebSocketFrame(msg.isFinalFragment(), rsv(msg), compressedContent);
120 } else if (msg instanceof ContinuationWebSocketFrame) {
121 outMsg = new ContinuationWebSocketFrame(msg.isFinalFragment(), rsv(msg), compressedContent);
122 } else {
123 throw new CodecException("unexpected frame type: " + msg.getClass().getName());
124 }
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126 out.add(outMsg);
127 }
128
129 @Override
130 public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
131 cleanup();
132 super.handlerRemoved(ctx);
133 }
134
135 private ByteBuf compressContent(ChannelHandlerContext ctx, WebSocketFrame msg) {
136 if (encoder == null) {
137 encoder = EmbeddedChannel.builder()
138 .handlers(ZlibCodecFactory.newZlibEncoder(
139 ZlibWrapper.NONE, compressionLevel, windowSize, memLevel))
140 .build();
141 }
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143 encoder.writeOutbound(msg.content().retain());
144
145 CompositeByteBuf fullCompressedContent = ctx.alloc().compositeBuffer();
146 for (;;) {
147 ByteBuf partCompressedContent = encoder.readOutbound();
148 if (partCompressedContent == null) {
149 break;
150 }
151 if (!partCompressedContent.isReadable()) {
152 partCompressedContent.release();
153 continue;
154 }
155 fullCompressedContent.addComponent(true, partCompressedContent);
156 }
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158 if (fullCompressedContent.numComponents() <= 0) {
159 fullCompressedContent.release();
160 throw new CodecException("cannot read compressed buffer");
161 }
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163 if (msg.isFinalFragment() && noContext) {
164 cleanup();
165 }
166
167 ByteBuf compressedContent;
168 if (removeFrameTail(msg)) {
169 int realLength = fullCompressedContent.readableBytes() - FRAME_TAIL.readableBytes();
170 compressedContent = fullCompressedContent.slice(0, realLength);
171 } else {
172 compressedContent = fullCompressedContent;
173 }
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175 return compressedContent;
176 }
177
178 private void cleanup() {
179 if (encoder != null) {
180
181 encoder.finishAndReleaseAll();
182 encoder = null;
183 }
184 }
185 }