Motivation:
Just was looking through code and found 1 interesting place DateFormatter.tryParseMonth that was not very effective, so I decided to optimize it a bit.
Modification:
Changed DateFormatter.tryParseMonth method. Instead of invocation regionMatch() for every month - compare chars one by one.
Result:
DateFormatter.parseHttpDate method performance improved from ~3% to ~15%.
Benchmark (DATE_STRING) Mode Cnt Score Error Units
DateFormatter2Benchmark.parseHttpHeaderDateFormatter Sun, 27 Jan 2016 19:18:46 GMT thrpt 6 4142781.221 ± 82155.002 ops/s
DateFormatter2Benchmark.parseHttpHeaderDateFormatter Sun, 27 Dec 2016 19:18:46 GMT thrpt 6 3781810.558 ± 38679.061 ops/s
DateFormatter2Benchmark.parseHttpHeaderDateFormatterNew Sun, 27 Jan 2016 19:18:46 GMT thrpt 6 4372569.705 ± 30257.537 ops/s
DateFormatter2Benchmark.parseHttpHeaderDateFormatterNew Sun, 27 Dec 2016 19:18:46 GMT thrpt 6 4339785.100 ± 57542.660 ops/s
Motivation
Implementations of MessageAggregator (HttpObjectAggregator in particular) may wish to
selectively aggrerage requests and responses on a case-by-case basis such as for example
only POST requests or only responses of a certain content-type.
Modifications
Adding a flag to MessageAggregator that toggles between true/false depending on if aggregation
is desired for the current message or not.
Result
Fixes#8772
Motivation:
We have a utility method to check for > 0 and >0 arguments. We should use it.
Modification:
use checkPositive/checkPositiveOrZero instead of if statement.
Result:
Re-use utility method.
Motivation:
We need to update to a new checkstyle plugin to allow the usage of lambdas.
Modifications:
- Update to new plugin version.
- Fix checkstyle problems.
Result:
Be able to use checkstyle plugin which supports new Java syntax.
Motivation:
LineBasedFrameDecoder, JsonObjectDecoder and XmlFrameDecoder upon investigation of the
sourcecode appeared to only support ASCII or UTF-8 input. It is an important characteristic
and ont reflected in any documentation. This could lead to improper usage and bugs.
Modifications:
Javadoc comment is addedd to all three classes to state that implementation is only
compatible with UTF-8 or ASCII input streams and brifly touches on implementaion details.
Result:
The end user of the netty library would not have to study sorcecode to deterime character
encoding limitations for given classes.
Motivation:
We had some typo (most likely caused by copy-and-paste) in the api docs which should be fixed.
Modifications:
Replace encoder by decoder word.
Result:
Correct apidocs.
Motivation:
If the encoder needs to flush more than one outbound message it will
create a new ChannelPromise for all but the last write which will
swallow failures.
Modification:
Use a PromiseCombiner in the case of multiple messages and the parent
promise isn't the `VoidPromise`.
Result:
Intermediate failures are propagated to the original ChannelPromise.
Motivation:
There are currently many more places where this could be used which were
possibly not considered when the method was added.
If https://github.com/netty/netty/pull/8388 is included in its current
form, a number of these places could additionally make use of the same
BYTE_ARRAYS threadlocal.
There's also a couple of adjacent places where an optimistically-pooled
heap buffer is used for temp byte storage which could use the
threadlocal too in preference to allocating a temp heap bytebuf wrapper.
For example
https://github.com/netty/netty/blob/4.1/buffer/src/main/java/io/netty/buffer/ByteBufUtil.java#L1417.
Modifications:
Replace new byte[] with PlatformDependent.allocateUninitializedArray()
where appropriate; make use of ByteBufUtil.getBytes() in some places
which currently perform the equivalent logic, including avoiding copy of
backing array if possible (although would be rare).
Result:
Further potential speed-up with java9+ and appropriate compile flags.
Many of these places could be on latency-sensitive code paths.
* Optimize AbstractByteBuf.getCharSequence() in US_ASCII case
Motivation:
Inspired by https://github.com/netty/netty/pull/8388, I noticed this
simple optimization to avoid char[] allocation (also suggested in a TODO
here).
Modifications:
Return an AsciiString from AbstractByteBuf.getCharSequence() if
requested charset is US_ASCII or ISO_8859_1 (latter thanks to
@Scottmitch's suggestion). Also tweak unit tests not to require Strings
and include a new benchmark to demonstrate the speedup.
Result:
Speed-up of AbstractByteBuf.getCharSequence() in ascii and iso 8859/1
cases
Motivation:
We need to ensure the Cumulator always releases the input buffer if it can not take over the ownership of it as otherwise it may leak.
Modifications:
- Correctly ensure the buffer is always released.
- Add unit tests.
Result:
Ensure buffer is always released.
Motivation:
In theory our estimation of the needed buffer could be off and so we need to ensure we grow it if there is no space left.
Modifications:
Ensure we grow the buffer if there is no space left in there but we still have data to deflate.
Result:
Correctly deflate data in all cases.
Motivation:
We need to reset the offset to 0 when we fail lazy because of a too long frame.
Modifications:
- Reset offset
- Add testcase
Result:
Fixes https://github.com/netty/netty/issues/8256.
Motivation:
The implementation of CharSequenceValueConverter.convertToByte did not correctly handle AsciiString if the length != 1.
Modifications:
- Only use fast-path for AsciiString with length of 1.
- Add unit tests.
Result:
Fixes https://github.com/netty/netty/issues/7990
Motivation:
We did not correctly copy elements in some cases when add(index, element) was used.
Modifications:
- Correctly detect when copy is neede and when not.
- Add test case.
Result:
Fixes https://github.com/netty/netty/issues/7938.
Motivation:
Some `if` statements contains common parts that can be extracted.
Modifications:
Extract common parts from `if` statements.
Result:
Less code and bytecode. The code is simpler and more clear.
Motivation:
When the JsonObjectDecoder determines that the incoming buffer had some data discarded, it resets the internal index to readerIndex and attempts to adjust the state which does not correctly work for streams of JSON objects.
Modifications:
Reset the internal index to the value considering the previous reads.
Result:
JsonObjectDecoder correctly handles streams of both JSON objects and arrays with no state adjustments or repeatable reads.
Motivation:
6e5fd9311f fixed a bug in EmptyHeaders which was never noticed before because we had no tests.
Modifications:
Add tests for EmptyHeaders.
Result:
EmptyHeaders is tested now.
Motivation:
EmptyHeaders#get with a default value argument returns null. It should never return null, and instead it should return the default value.
Modifications:
- EmptyHeaders#get with a default value should return that default value
Result:
More correct implementation of the Headers API.
Motivation:
The Snappy decoder was failing on valid inputs containing literals
with 2-byte lengths > 0x8000 or copies with 2-byte offsets >= 0x8000.
The decoder was also enforcing an artificially low offset limit of
0x7FFF, something the Snappy format description advises against,
and which prevents decoding valid inputs generated by other encoders.
Modifications:
Interpret 2-byte literal lengths and 2-byte copy offsets as unsigned
shorts, in accordance with the format description and reference
implementation.
Allow any positive offset value. Throw an appropriate exception
for negative values (which can theoretically occur due to arithmetic
overflow on 4-byte offsets, but are unlikely to occur in the wild).
Result:
The Snappy decoder can handle valid inputs that previously caused
it to throw exceptions.
Motivation:
CharSequenceValueConverter#convertToBoolean has a few manual conditionals which can be removed if we use AsciiString.contentEqualsIgnoreCase. Also by comparing an AsciiString to a String we will incur conversions to char that can be avoided if we compare against AsciiString.
Modifications:
- Use AsciiString.contentEqualsIgnoreCase
- Compare against a AsciiString
Result:
Simplified CharSequenceValueConverter#convertToBoolean which favors AsciiString comparison.
Motivation:
If you pass the output of CharSequenceValueConvert.convertToTimeMillis to convertTimeMillis it will throw a ParseException.
Modifications:
- Correctly implement CharSequenceValueConverter.convertTimeMillis
- Add unit-tests for CharSequenceValueConverter
Result:
Correctly convert timemillis.
Motivation:
HeaderEntry.equals() inherets Object.equals() which simply check if two objects are the same.
So it returns false even when two HeaderEntry objects have the same name and value.
Modifications:
Implement HeaderEntry.equals() that follows the specification of Map.Entry.equals().
https://docs.oracle.com/javase/9/docs/api/java/util/Map.Entry.html#equals-java.lang.Object-
Result:
HeaderEntry.equals() returns true if two HeaderEntry objects have the same name and value.
Motivation:
HttpHeaders.getBoolean should return the same truth value for the same string value, regardless of the underlying type.
Modifications:
- Only treat values of true as Boolean.TRUE
- Add unit tests.
Result:
Consistent converting of values for all CharSequence implementations.
Motivation:
Headers.get* methods should not throw an exception but return null or the default value if converting of the value fails.
Modifications:
- Correctly handle the case when ValueConverter throws an Exception.
- Add testcase.
Result:
Fixes [#7710].
Motivation:
We used Recycler for the CodecOutputList which is not optimized for the use-case of access only from the same Thread all the time.
Modifications:
- Use FastThreadLocal for CodecOutputList
- Add benchmark
Result:
Less overhead in our codecs.
Motivation:
Will allow easy removal of deprecated methods in future.
Modification:
Replaced ctx.attr(), ctx.hasAttr() with ctx.channel().attr(), ctx.channel().hasAttr().
Result:
No deprecated ctx.attr(), ctx.hasAttr() methods usage.
Motivation:
According to RFC 1952, concatenation of valid gzip streams is also a valid gzip stream. JdkZlibDecoder only processed the first and discarded the rest.
Modifications:
- Introduced a constructor argument decompressConcatenated that if true, JdkZlibDecoder would continue to process the stream.
Result:
- If 'decompressConcatenated = true', concatenated streams would be processed in
compliance to RFC 1952.
- If 'decompressConcatenated = false' (default), existing behavior would remain.
Motivation:
Allow pre-computing calculation of the constants for compiler where it could be.
Similar fix in OpenJDK: [1].
Modifications:
- Use parentheses.
- Simplify static initialization of `BYTE2HEX_*` arrays in `StringUtil`.
Result:
Less bytecode, possible faster calculations at runtime.
[1] https://bugs.openjdk.java.net/browse/JDK-4477961
Motiviation:
In our replace(...) methods we always used validation for the newly created headers while the original headers may not use validation at all.
Modifications:
- Only use validation if the original headers used validation as well.
- Ensure we create a copy of the headers in replace(...).
Result:
Fixes [#5226]
Motivation:
DefaultHttpHeader.names() exposes HTTP header names as a Set<String>. Converting the resulting set to an array using toArray(String[]) throws an exception: java.lang.ArrayStoreException: io.netty.util.AsciiString.
Modifications:
- Remove our custom implementation of toArray(...) (and others) by just extending AbstractCollection.
- Add unit test
Result:
Fixes [#7428].
Motivation:
For debugging/logging purpose, it would be convenient to have
HttpHeaders#toString implemented.
DefaultHeaders does implement toString be the implementation is suboptimal and allocates a Set for the names and Lists for values.
Modification:
* Introduce HeadersUtil#toString that provides a convenient optimized helper to implement toString for various headers implementations
* Have DefaultHeaders#toString and HttpHeaders#toString delegate their toString implementation to HeadersUtil
Result:
Convenient HttpHeaders#toString. Optimized DefaultHeaders#toString.
Motivation:
HttpObjectEncoder and MessageAggregator treat buffers that are not readable special. If a buffer is not readable, then an EMPTY_BUFFER is written and the actual buffer is ignored. If the buffer has already been released then this will not be correct as the promise will be completed, but in reality the original content shouldn't have resulted in any write because it was invalid.
Modifications:
- HttpObjectEncoder should retain/write the original buffer instead of using EMPTY_BUFFER
- MessageAggregator should retain/write the original ByteBufHolder instead of using EMPTY_BUFFER
Result:
Invalid write operations which happen to not be readable correctly reflect failed status in the promise, and do not result in any writes to the channel.
Motivation:
Use actual links to new locations of Protobuf repo and documentation to
avoid problems when redirect will not work.
Modification:
Links in comments and all/pom.xml
Result:
Correct links to Protobuf resources
Motivation:
Even if it's a super micro-optimization (most JVM could optimize such
cases in runtime), in theory (and according to some perf tests) it
may help a bit. It also makes a code more clear and allows you to
access such methods in the test scope directly, without instance of
the class.
Modifications:
Add 'static' modifier for all methods, where it possible. Mostly in
test scope.
Result:
Cleaner code with proper 'static' modifiers.
Motivation:
Without a 'serialVersionUID' field, any change to a class will make
previously serialized versions unreadable.
Modifications:
Add missed 'serialVersionUID' field for all Serializable
classes.
Result:
Proper deserialization of previously serialized objects.
Motivation: Today when Netty encounters a general error while decoding
it treats this as a decoder exception. However, for fatal causes this
should not be treated as such, instead the fatal error should be carried
up the stack without the callee having to unwind causes. This was
probably done for byte to byte message decoder but is now done for all
decoders.
Modifications: Instead of translating any error to a decoder exception,
we let those unwind out the stack (note that finally blocks still
execute) except in places where an event needs to fire where we fire
with the error instead of wrapping in a decoder exception.
Result: Fatal errors will not be treated as innocent decoder exceptions.
Motivation: Today when Netty encounters a general error while decoding
it treats this as a decoder exception. However, for fatal causes this
should not be treated as such, instead the fatal error should be carried
up the stack without the callee having to unwind causes.
Modifications: Instead of translating any error to a decoder exception,
we let those unwind out the stack (note that finally blocks still
execute).
Result: Fatal errors will not be treated as innocent decoder exceptions.
Motivation:
A large frame will be componsed by many packages. Every time the package
arrived, findEndOfLine will be called from the start of the buffer. It
will cause the complexity of reading frame equal to O(n^2). This can be
eliminated by using a offset to mark the last scan position, when new
package arrived, just find the delimter from the mark. The complexity
will be O(n).
Modification:
Add a offset to mark the last scan position.
Result:
Better performance for read large frame.
Motivation:
The Headers interface supports an interface to get all the headers values corresponding to a particular name. This API returns a List which requires intermediate storage and increases GC pressure.
Modifications:
- Add a method which returns an iterator over all the values for a specific name
Result:
Ability to iterator over values for a specific name with no intermediate collection.
Motivation:
The decode method is too large to be inlined with default compiler settings, hence the uncommon paths need to be packed and moved away form the common one.
Modifications:
The uncommon paths of the decode call (eg failures with thrown exceptions) are packed and moved in private methods in order to reduce the size of the common one
and let it being inlined.
Result:
The decode method is being inlined if the stack depth allows it.
Motivation:
Continuing to make netty happy when compiling through errorprone.
Modification:
Mostly comments, some minor switch statement changes.
Result:
No more compiler errors!
Motivation:
Calling `newInstance()` on a Class object can bypass compile time
checked Exception propagation. This is noted in Java Puzzlers,
as well as in ErrorProne:
http://errorprone.info/bugpattern/ClassNewInstance
Modifications:
Use the niladic constructor to create a new instance.
Result:
Compile time safety for checked exceptions
This reverts commit d63bb4811e as this not covered correctly all cases and so could lead to missing fireChannelReadComplete() calls. We will re-evalute d63bb4811e and resbumit a pr once we are sure all is handled correctly
Motivation:
'insideString' and 'openBraces' need a proper handling when streaming
Json array over multiple writes and an element decoding was started but
not completed.
Related to #6969
Modifications:
If the idx is reset:
- 'insideString' has to be reset to 'false' in order to indicate that
array element will be decoded from the beginning
- 'openBraces' has to be reset to '1' to indicate that Json array
decoding is in progress.
Result:
Json array is properly decoded when in streaming mode
Motivation:
Its wasteful and also confusing that channelReadComplete() is called even if there was no message forwarded to the next handler.
Modifications:
- Only call ctx.fireChannelReadComplete() if at least one message was decoded
- Add unit test
Result:
Less confusing behavior. Fixes [#4312].
Motivation:
1. Hash function in the Snappy encoding is wrong probably: used '+' instead of '*'. See the reference implementation [1].
2. Size of the hash table is calculated, but not applied.
Modifications:
1. Fix hash function: replace addition by multiplication.
2. Allocate hash table with calculated size.
3. Use an `Integer.numberOfLeadingZeros` trick for calculate log2.
4. Release buffers in tests.
Result:
1. Better compression. In the test `encodeAndDecodeLongTextUsesCopy` now compressed size is 175 instead of 180 before this change.
2. No redundant allocations for hash table.
3. A bit faster the calc of shift (less an expensive math operations).
[1] 513df5fb5a/snappy.cc (L67)
Motivation:
Calling JsonObjectDecoder#reset while streaming Json array over multiple
writes causes CorruptedFrameException to be thrown.
Modifications:
While streaming Json array and if the current readerIndex has been reset,
ensure that the states will not be reset.
Result:
Fixes#6969
