com.spotify.netty4.handler.codec.zmtp.VerifyingDecoder.java Source code

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Here is the source code for com.spotify.netty4.handler.codec.zmtp.VerifyingDecoder.java

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/*
 * Copyright (c) 2012-2015 Spotify AB
 *
 * Licensed 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.
 */

package com.spotify.netty4.handler.codec.zmtp;

import java.util.List;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;

public class VerifyingDecoder implements ZMTPDecoder {

    private ExpectedOutput expected;

    private int readIndex;
    private boolean finished;
    private long frameSize;

    public VerifyingDecoder(final ExpectedOutput expected) {
        this.expected = expected;
    }

    public VerifyingDecoder() {
    }

    public void expect(ExpectedOutput expected) {
        this.expected = expected;
    }

    @Override
    public void header(final ChannelHandlerContext ctx, final long length, final boolean more,
            final List<Object> out) {
        if (finished) {
            throw new IllegalStateException("already finished");
        }
        if (readIndex >= expected.message.size()) {
            throw new IllegalStateException("more frames than expected: " + "readIndex=" + readIndex + ", "
                    + "expected=" + expected + ", frame(size=" + length + ", more=" + more + ")");
        }
        frameSize = length;
    }

    @Override
    public void content(final ChannelHandlerContext ctx, final ByteBuf data, final List<Object> out) {
        if (data.readableBytes() < frameSize) {
            return;
        }
        final ByteBuf expectedFrame = expected.message.frame(readIndex);
        final ByteBuf frame = data.readBytes((int) frameSize);
        if (!expectedFrame.equals(frame)) {
            throw new IllegalStateException("read frame did not match expected frame: " + "readIndex=" + readIndex
                    + ", " + "expected frame=" + expectedFrame + "read frame=" + frame);
        }
        readIndex++;
    }

    @Override
    public void finish(final ChannelHandlerContext ctx, final List<Object> out) {
        if (finished) {
            throw new IllegalStateException("already finished");
        }
        if (readIndex != expected.message.size()) {
            throw new IllegalStateException(
                    "less than expected frames read: " + "readIndex=" + readIndex + ", " + "expected=" + expected);
        }
        readIndex = 0;
        finished = true;
    }

    @Override
    public void close() {
    }

    public void assertFinished() {
        if (!finished) {
            throw new AssertionError("not finished");
        }
        finished = false;
    }

    static class ExpectedOutput {

        private final ZMTPMessage message;

        public ExpectedOutput(final ZMTPMessage message) {
            this.message = message;
        }

        @Override
        public String toString() {
            return message.toString();
        }
    }
}