Snappy compression failures

[shemnon]

PR description

Possible fix for #251 - swap out a JNI based library for an all-Java library

Fixed Issue(s)

#251

[ajsutton]

Well, we did get better error messages:

2018-11-14 07:27:12.068+10:00 | nioEventLoopGroup-3-1 | ERROR | DeFramer | Exception while processing incoming message
io.netty.handler.codec.DecoderException: org.iq80.snappy.CorruptionException: Recorded length is 1473 bytes but actual length after decompression is 0 bytes
        at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:459) ~[netty-codec-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:265) ~[netty-codec-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1359) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:935) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:134) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:645) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:580) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:497) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:459) [netty-transport-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:858) [netty-common-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.util.concurrent.DefaultThreadFactory$DefaultRunnableDecorator.run(DefaultThreadFactory.java:138) [netty-common-4.1.15.Final.jar:4.1.15.Final]
        at java.lang.Thread.run(Thread.java:745) [?:1.8.0_25]
Caused by: org.iq80.snappy.CorruptionException: Recorded length is 1473 bytes but actual length after decompression is 0 bytes
        at org.iq80.snappy.SnappyDecompressor.uncompress(SnappyDecompressor.java:55) ~[snappy-0.4.jar:?]
        at org.iq80.snappy.Snappy.uncompress(Snappy.java:85) ~[snappy-0.4.jar:?]
        at tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.SnappyCompressor.decompress(SnappyCompressor.java:35) ~[pantheon-p2p-0.9.0-SNAPSHOT.jar:0.9.0-SNAPSHOT]
        at tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.Framer.processFrame(Framer.java:265) ~[pantheon-p2p-0.9.0-SNAPSHOT.jar:0.9.0-SNAPSHOT]
        at tech.pegasys.pantheon.ethereum.p2p.rlpx.framing.Framer.deframe(Framer.java:156) ~[pantheon-p2p-0.9.0-SNAPSHOT.jar:0.9.0-SNAPSHOT]
        at tech.pegasys.pantheon.ethereum.p2p.netty.DeFramer.decode(DeFramer.java:67) ~[pantheon-p2p-0.9.0-SNAPSHOT.jar:0.9.0-SNAPSHOT]
        at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:489) ~[netty-codec-4.1.15.Final.jar:4.1.15.Final]
        at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:428) ~[netty-codec-4.1.15.Final.jar:4.1.15.Final]
        ... 16 more

[ajsutton]

LGTM. Won't fix the issue but less JNI and better error messages is definitely worth while.