io.netty.handler.codec.spdy.SpdyHeaderBlockZlibEncoder Maven / Gradle / Ivy

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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

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/*
 * Copyright 2013 The Netty Project
 *
 * The Netty Project 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:
 *
 *   https://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.
 */
package io.netty.handler.codec.spdy;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.Unpooled;
import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.SuppressJava6Requirement;

import java.util.zip.Deflater;

import static io.netty.handler.codec.spdy.SpdyCodecUtil.*;
import static io.netty.util.internal.ObjectUtil.checkNotNullWithIAE;

class SpdyHeaderBlockZlibEncoder extends SpdyHeaderBlockRawEncoder {

    private final Deflater compressor;

    private boolean finished;

    SpdyHeaderBlockZlibEncoder(SpdyVersion spdyVersion, int compressionLevel) {
        super(spdyVersion);
        if (compressionLevel < 0 || compressionLevel > 9) {
            throw new IllegalArgumentException(
                    "compressionLevel: " + compressionLevel + " (expected: 0-9)");
        }
        compressor = new Deflater(compressionLevel);
        compressor.setDictionary(SPDY_DICT);
    }

    private int setInput(ByteBuf decompressed) {
        int len = decompressed.readableBytes();

        if (decompressed.hasArray()) {
            compressor.setInput(decompressed.array(), decompressed.arrayOffset() + decompressed.readerIndex(), len);
        } else {
            byte[] in = new byte[len];
            decompressed.getBytes(decompressed.readerIndex(), in);
            compressor.setInput(in, 0, in.length);
        }

        return len;
    }

    private ByteBuf encode(ByteBufAllocator alloc, int len) {
        ByteBuf compressed = alloc.heapBuffer(len);
        boolean release = true;
        try {
            while (compressInto(compressed)) {
                // Although unlikely, it's possible that the compressed size is larger than the decompressed size
                compressed.ensureWritable(compressed.capacity() << 1);
            }
            release = false;
            return compressed;
        } finally {
            if (release) {
                compressed.release();
            }
        }
    }

    @SuppressJava6Requirement(reason = "Guarded by java version check")
    private boolean compressInto(ByteBuf compressed) {
        byte[] out = compressed.array();
        int off = compressed.arrayOffset() + compressed.writerIndex();
        int toWrite = compressed.writableBytes();
        final int numBytes;
        if (PlatformDependent.javaVersion() >= 7) {
            numBytes = compressor.deflate(out, off, toWrite, Deflater.SYNC_FLUSH);
        } else {
            numBytes = compressor.deflate(out, off, toWrite);
        }
        compressed.writerIndex(compressed.writerIndex() + numBytes);
        return numBytes == toWrite;
    }

    @Override
    public ByteBuf encode(ByteBufAllocator alloc, SpdyHeadersFrame frame) throws Exception {
        checkNotNullWithIAE(alloc, "alloc");
        checkNotNullWithIAE(frame, "frame");

        if (finished) {
            return Unpooled.EMPTY_BUFFER;
        }

        ByteBuf decompressed = super.encode(alloc, frame);
        try {
            if (!decompressed.isReadable()) {
                return Unpooled.EMPTY_BUFFER;
            }

            int len = setInput(decompressed);
            return encode(alloc, len);
        } finally {
            decompressed.release();
        }
    }

    @Override
    public void end() {
        if (finished) {
            return;
        }
        finished = true;
        compressor.end();
        super.end();
    }
}