Motivation :
Unboxing operations allocate unnecessary objects when it could be avoided.
Modifications:
Replaced Float.valueOf with Number.parseFloat where possible.
Result:
Less unnecessary objects allocations.
Motivation:
We are currently doing a memory copy to verify the snapy version. This is not needed.
Modifications:
Remove memory copy and just compare byte per byte.
Result:
Less memory copies and allocations
Motivation:
We need to ensure the uncompressed ByteBuf is released if an exception happens while calling decode(...). If we miss to do so we leak buffers.
Modifications:
Correctly release buffer on exception.
Result:
No more memory leak.
Motivation:
We not need to do any memory copies when doing CRC32 processing.
Modifications:
Use ByteBufChecksum to eliminate memory copies.
Result:
Less memory copies.
Motivation:
We should try to minimize memory copies whenever possible.
Modifications:
- Refactor ByteBufChecksum to work with heap and direct ByteBuf always
- Remove memory copy in Snappy by let Crc32c extend ByteBufChecksum
Result:
Less memory copies when using Snappy
Motivation:
We did an unessary memory copy when doing bzip2 encoding.
Modifications:
Remove memory copy and just use a ByteProcessor.
Result:
Less memory copies and so faster.
Motivation:
We should prefer direct buffers for the output of Lz4FrameEncoder as this is what is needed for writing to the socket.
Modification:
Use direct buffers for the output
Result:
Less memory copies needed.
Motivation:
When the user constructs Lz4FrameDecoder with a Checksum implementation like CRC32 or Adler32 and uses Java8 we can directly use a ByteBuffer to do the checksum work. This way we can eliminate memory copies.
Modifications:
Detect if ByteBuffer can be used for checksum work and if so reduce memory copies.
Result:
Less memory copies when using JDK8
Motivation:
HPACK Encoder has a data structure which is similar to a previous version of DefaultHeaders. Some of the same improvements can be made.
Motivation:
- Enforce the restriction that the Encoder's headerFields length must be a power of two so we can use masking instead of modulo
- Use AsciiString.hashCode which already has optimizations instead of having yet another hash code algorithm in Encoder
Result:
Fixes https://github.com/netty/netty/issues/5357
Motivation:
PlatformDependent attempts to use reflection to get the underlying char[] (or byte[]) from String objects. This is fragile as if the String implementation does not utilize the full array, and instead uses a subset of the array, this optimization is invalid. OpenJDK6 and some earlier versions of OpenJDK7 String have the capability to use a subsection of the underlying char[].
Modifications:
- PlatformDependent should not attempt to use the underlying array from String (or other data types) via reflection
Result:
PlatformDependent hash code generation for CharSequence does not depend upon specific JDK implementation details.
Motivation:
It is good to have used dependencies and plugins up-to-date to fix any undiscovered bug fixed by the authors.
Modification:
Scanned dependencies and plugins and carefully updated one by one.
Result:
Dependencies and plugins are up-to-date.
Motivation:
JCTools supports both non-unsafe, unsafe versions of queues and JDK6 which allows us to shade the library in netty-common allowing it to stay "zero dependency".
Modifications:
- Remove copy paste JCTools code and shade the library (dependencies that are shaded should be removed from the <dependencies> section of the generated POM).
- Remove usage of OneTimeTask and remove it all together.
Result:
Less code to maintain and easier to update JCTools and less GC pressure as the queue implementation nt creates so much garbage
Motivation:
We should ensure we null out the cumulation buffer before we fire it through the pipleine in handlerRemoved(...) as in theory it could be possible that another method is triggered as result of the fireChannelRead(...) or fireChannelReadComplete() that will try to access the cumulation.
Modifications:
Null out cumulation buffer early in handlerRemoved(...)
Result:
No possible to access the cumulation buffer that was already handed over.
Motivation:
For example,
DefaultHttp2Headers headers = new DefaultHttp2Headers();
headers.add("key1", "value1");
headers.add("key1", "value2");
headers.add("key1", "value3");
headers.add("key2", "value4");
produces:
DefaultHttp2Headers[key1: value1key1: value2key1: value3, key2: value4]
while correctly it should be
DefaultHttp2Headers[key1: value1, key1: value2, key1: value3, key2: value4]
Modifications:
Change the toString() method to produce the beforementioned output.
Result:
toString() format is correct also for keys with multiple values.
Motivation:
At the moment the user is responsible to increase the writer index of the composite buffer when a new component is added. We should add some methods that handle this for the user as this is the most popular usage of the composite buffer.
Modifications:
Add new methods that autoamtically increase the writerIndex when buffers are added.
Result:
Easier usage of CompositeByteBuf.
Motivation:
99dfc9ea79 introduced some code that will more frequently try to forward messages out of the list of decoded messages to reduce latency and memory footprint. Unfortunally this has the side-effect that RecycleableArrayList.clear() will be called more often and so introduce some overhead as ArrayList will null out the array on each call.
Modifications:
- Introduce a CodecOutputList which allows to not null out the array until we recycle it and also allows to access internal array with extra range checks.
- Add benchmark that add elements to different List implementations and clear them
Result:
Less overhead when decode / encode messages.
Benchmark (elements) Mode Cnt Score Error Units
CodecOutputListBenchmark.arrayList 1 thrpt 20 24853764.609 ± 161582.376 ops/s
CodecOutputListBenchmark.arrayList 4 thrpt 20 17310636.508 ± 930517.403 ops/s
CodecOutputListBenchmark.codecOutList 1 thrpt 20 26670751.661 ± 587812.655 ops/s
CodecOutputListBenchmark.codecOutList 4 thrpt 20 25166421.089 ± 166945.599 ops/s
CodecOutputListBenchmark.recyclableArrayList 1 thrpt 20 24565992.626 ± 210017.290 ops/s
CodecOutputListBenchmark.recyclableArrayList 4 thrpt 20 18477881.775 ± 157003.777 ops/s
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 246.748 sec - in io.netty.handler.codec.CodecOutputListBenchmark
Related: #4333#4421#5128
Motivation:
slice(), duplicate() and readSlice() currently create a non-recyclable
derived buffer instance. Under heavy load, an application that creates a
lot of derived buffers can put the garbage collector under pressure.
Modifications:
- Add the following methods which creates a non-recyclable derived buffer
- retainedSlice()
- retainedDuplicate()
- readRetainedSlice()
- Add the new recyclable derived buffer implementations, which has its
own reference count value
- Add ByteBufHolder.retainedDuplicate()
- Add ByteBufHolder.replace(ByteBuf) so that..
- a user can replace the content of the holder in a consistent way
- copy/duplicate/retainedDuplicate() can delegate the holder
construction to replace(ByteBuf)
- Use retainedDuplicate() and retainedSlice() wherever possible
- Miscellaneous:
- Rename DuplicateByteBufTest to DuplicatedByteBufTest (missing 'D')
- Make ReplayingDecoderByteBuf.reject() return an exception instead of
throwing it so that its callers don't need to add dummy return
statement
Result:
Derived buffers are now recycled when created via retainedSlice() and
retainedDuplicate() and derived from a pooled buffer
Motivation:
Often users either need to read or write CharSequences to a ByteBuf. We should add methods for this to ByteBuf as we can do some optimizations for this depending on the implementation.
Modifications:
Add setCharSequence, writeCharSequence, getCharSequence and readCharSequence
Result:
Easier reading / writing of CharSequence with ByteBuf.
Motivation:
The double quote may be escaped in a JSON string, but JsonObjectDecoder doesn't handle it. Resolves#5157.
Modifications:
Don't end a JSON string when processing an escaped double quote.
Result:
JsonObjectDecoder can handle backslash and double quote in a JSON string correctly.
Motivation:
We lately added ByteBuf.isReadOnly() which allows to detect if a buffer is read-only or not. We should add ByteBuf.asReadOnly() to allow easily access a read-only version of a buffer.
Modifications:
- Add ByteBuf.asReadOnly()
- Deprecate Unpooled.unmodifiableBuffer(Bytebuf)
Result:
More consistent api.
Motivation:
b112673554 added ChannelInputShutdownEvent support to ByteToMessageDecoder but missed updating the code for ReplayingDecoder. This has the effect:
- If a ChannelInputShutdownEvent is fired ByteToMessageDecoder (the super-class of ReplayingDecoder) will call the channelInputClosed(...) method which will pass the incorrect buffer to the decode method of ReplayingDecoder.
Modifications:
Share more code between ByteToMessageDEcoder and ReplayingDecoder and so also support ChannelInputShutdownEvent correctly in ReplayingDecoder
Result:
ChannelInputShutdownEvent is corrrectly handle in ReplayingDecoder as well.
We need to check if this handler was removed before continuing with decoding.
If it was removed, it is not safe to continue to operate on the buffer. This was already fixed for ByteToMessageDecoder in 4cdbe39284 but missed for ReplayingDecoder.
Modifications:
Check if decoder was removed after fire messages through the pipeline.
Result:
No illegal buffer access when decoder was removed.
Motivation:
We use ByteBuf.readBytes(int) in various places where we could either remove it completely or use readSlice(int).retain().
Modifications:
- Remove ByteBuf.readBytes(int) when possible or replace by readSlice(int).retain().
Result:
Faster code.
Motivation:
See #1811
Modifications:
Add LineEncoder and LineSeparator
Result:
The user can use LineEncoder to write a String with a line separator automatically
Motivation:
UDP-oriented codec reusing the existing encoders and decoders would be helpful. See #1350
Modifications:
Add DatagramPacketEncoder and DatagramPacketDecoder to reuse the existing encoders and decoders.
Result:
People can use DatagramPacketEncoder and DatagramPacketDecoder to wrap existing encoders and decoders to create UDP-oriented codec.
Motivation:
If the input buffer is empty we should not have decodeLast(...) call decode(...) as the user may not expect this.
Modifications:
- Not call decode(...) in decodeLast(...) if the input buffer is empty.
- Add testcases.
Result:
decodeLast(...) will not call decode(...) if input buffer is empty.
Motivation:
Each call of ByteBuf.getByte(int) method does boundary checking. This can be eliminated by using ByteBuf.forEachByte(ByteProcessor) method and ByteProcessor.FIND_LF processor.
Modifications:
Find end of line with ByteProcessor.FIND_LF
Result:
A little better performance of LineBasedFrameDecoder.
Motivation:
Some people may want to use the Snappy class directly to encode / decode ByteBufs.
Modifications:
Make the Snappy class public and final.
Result:
Easier for people to reuse parts of Netty.
