Commit Graph

477 Commits

Author SHA1 Message Date
Scott Mitchell
7494e84208 PlatformDependent static initialization ExceptionInInitializerError
Motivation:
PlatformDependent allows some exceptions to escape during static initialization. If an exception escapes it will be translated into a java.lang.ExceptionInInitializerError and render the application unable to run.

Modifications:
- Make sure to catch Throwable during static initialization.

Result:
PlatformDependent static initialization doesn't result in java.lang.ExceptionInInitializerError.
2016-01-20 06:13:36 -08:00
Norman Maurer
7b51412c3c Allow to do async mappings in the SniHandler
Motivation:

Sometimes a user want to do async mappings in the SniHandler as it is not possible to populate a Mapping up front.

Modifications:

Add AsyncMapping interface and make SniHandler work with it.

Result:

It is possible to do async mappings for SNI
2016-01-18 21:02:13 +01:00
Scott Mitchell
7dba13f276 HttpConversionUtil remove throws from method signature
Motivation:
HttpConversionUtil.toHttp2Headers currently has a throws Exception as part of the signature. This comes from the signature of ByteProcessor.process, but is not necessary because the ByteProcessor used does not throw.

Modifications:
- Remove throws Exception from the signature of HttpConversionUtil.toHttp2Headers.

Result:
HttpConversionUtil.toHttp2Headers interface does not propagate a throws Exception when it is used.
2016-01-15 10:53:34 +01:00
Stephane Landelle
b4be040f30 Introduce DnsCache API + DnsResolver extensibility
Motivation:
Caching is currently nested in DnsResolver.
It should also be possible to extend DnsResolver to ba able to pass a different cache on each resolution attemp.

Modifications:

* Introduce DnsCache, NoopDnsCache and DefaultDnsCache. The latter contains all the current caching logic that was extracted.
* Introduce protected versions of doResolve and doResolveAll that can be used as extension points to build resolvers that bypass the main cache and use a different one on each resolution.

Result:

Isolated caching logic. Better extensibility.
2016-01-08 14:46:47 +01:00
Stephane Landelle
1bee71fb1c Fix PlatformDependent.newAtomic*FieldUpdater type safety
Motivation:

* newAtomicIntegerFieldUpdater and newAtomicLongFieldUpdater take a
class<?> so they're too lax
* newAtomicReferenceFieldUpdater takes a Class<U> so it's too strict
and can only be passe a rawtype parameter when dealing w/ generic
classes

Modifications:

Take a Class<? super T> parameter instead.

Result:

Better type safety and generics support.
2016-01-08 08:51:24 +01:00
Fabian Lange
619d82b56f Removed unused imports
Motivation:

Warnings in IDE, unclean code, negligible performance impact.

Modification:

Deletion of unused imports

Result:

No more warnings in IDE, cleaner code, negligible performance improvement.
2016-01-04 14:32:29 +01:00
Xiaoyan Lin
475d901131 Fix errors reported by javadoc
Motivation:

Javadoc reports errors about invalid docs.

Modifications:

Fix some errors reported by javadoc.

Result:

A lot of javadoc errors are fixed by this patch.
2015-12-27 08:36:45 +01:00
Xiaoyan Lin
a96d52fe66 Fix javadoc links and tags
Motivation:

There are some wrong links and tags in javadoc.

Modifications:

Fix the wrong links and tags in javadoc.

Result:

These links will work correctly in javadoc.
2015-12-26 08:34:31 +01:00
eantaev
7c1602125a Builder to construct DomainNameMapping.
Motivation:

DomainNameMapping.add() makes DomainNameMapping look like it's safe to call add() anytime, and this is never true. It's probably better deprecate add() and introduce DomainNameMappingBuilder.

Modifications:

Made an immutable implementation of DomainNameMapping;
Added Builder for immutable DomainNameMapping;
Replaced regex pattern with String::startsWith check;
Replaced HashMap with two arrays in ImmutableDomainNameMapping;
Deprecated mutable API;
Estimation for StringBuilder initial size in ImmutableDomainNameMapping#toString()
Added StringUtil#commonSuffixOfLength
Replaced unnecessary substrings creation in DomainNameMapping#matches with regionMatches

Result:

Clients will be able to create immutable instances of DomainNameMapping with builder API.
2015-12-20 18:50:09 +01:00
Scott Mitchell
f750d6e36c ByteBufUtil.writeUtf8 Surrogate Support
Motivation:
UTF-16 can not represent the full range of Unicode characters, and thus has the concept of Surrogate Pair (http://unicode.org/glossary/#surrogate_pair) where 2 16-bit code units can be used to represent the missing characters. ByteBufUtil.writeUtf8 is currently does not support this and is thus incomplete.

Modifications:
- Add support for surrogate pairs in ByteBufUtil.writeUtf8

Result:
ByteBufUtil.writeUtf8 now supports surrogate pairs and is correctly converting to UTF-8.
2015-12-18 13:51:52 -08:00
Scott Mitchell
904e70a4d4 HTTP/2 Weighted Fair Queue Byte Distributor
Motivation:
PriorityStreamByteDistributor uses a homegrown algorithm which distributes bytes to nodes in the priority tree. PriorityStreamByteDistributor has no concept of goodput which may result in poor utilization of network resources. PriorityStreamByteDistributor also has performance issues related to the tree traversal approach and number of nodes that must be visited. There also exists some more proven algorithms from the resource scheduling domain which PriorityStreamByteDistributor does not employ.

Modifications:
- Introduce a new ByteDistributor which uses elements from weighted fair queue schedulers

Result:
StreamByteDistributor which is sensitive to priority and uses a more familiar distribution concept.
Fixes https://github.com/netty/netty/issues/4462
2015-12-17 11:17:02 -08:00
Stephane Landelle
8d4db050f3 Have hosts file support for DnsNameResolver, close #4074
Motivation:

On contrary to `DefaultNameResolver`, `DnsNameResolver` doesn't currently honor hosts file.

Modifications:

* Introduce `HostsFileParser` that parses `/etc/hosts` or `C:\Windows\system32\drivers\etc\hosts` depending on the platform
* Introduce `HostsFileEntriesResolver` that uses the former to resolve host names
* Make `DnsNameResolver` check his `HostsFileEntriesResolver` prior to trying to resolve names against the DNS server
* Introduce `DnsNameResolverBuilder` so we now have a builder for `DnsNameResolver`s
* Additionally introduce a `CompositeNameResolver` that takes several `NameResolver`s and tries to resolve names by delegating sequentially
* Change `DnsNameResolver.asAddressResolver` to return a composite and honor hosts file

Result:

Hosts file support when using `DnsNameResolver`.
Consistent behavior with JDK implementation.
2015-12-17 15:15:42 +01:00
Brendt Lucas
e8eda1b99f Fix AsciiString.contentEqualsIgnoreCase
Motivation:

Related to issue #4564.

AsciiString.contentEqualsIgnoreCase fails when comparing two AsciiStrings of the same length

Modifications:

Compare the values of the first AsciiString to the second AsciiString

Result:

AsciiString.contentEqualsIgnoreCase works as expected
2015-12-12 19:48:17 +01:00
Scott Mitchell
32933821bb AbstractFuture should not wrap CancellationException
Motivation:
AbstractFuture currently wraps CancellationException in a ExecutionException. However the interface of Future says that this exception should be directly thrown.

Modifications:
- Throw CancellationException from AbstractFuture.get

Result:
Interface contract for CancellationException is honored in AbstractFuture.
2015-12-11 10:24:08 -08:00
Scott Mitchell
6257091d12 HttpConversionUtil does not account for COOKIE compression
Motivation:
The HTTP/2 RFC allows for COOKIE values to be split into individual header elements to get more benefit from compression (https://tools.ietf.org/html/rfc7540#section-8.1.2.5). HttpConversionUtil was not accounting for this behavior.

Modifications:
- Modify HttpConversionUtil to support compressing and decompressing the COOKIE values

Result:
HttpConversionUtil is compatible with https://tools.ietf.org/html/rfc7540#section-8.1.2.5)
Fixes https://github.com/netty/netty/issues/4457
2015-12-08 20:00:31 -08:00
Scott Mitchell
1f3fc983c0 DefaultPromise LateListener notification order
Motivation:
There is a notification ordering issue in DefaultPromise when the lateListener collection is in use. The ordering issue can be observed in situations where a late listener is added to a Future returned from a write operation. It is possible that this future will run after a read operation scheduled on the I/O thread, even if the late listener is added on the I/O thread. This can lead to unexpected ordering where a listener for a write operation which must complete in order for the read operation to happen is notified after the read operation is done.

Modifications:
- If the lateListener collection becomes empty, it should be treated as though it was null when checking if lateListeners can be notified immediatley (instead of executing a task on the executor)

Result:
Ordering is more natural and will not be perceived as being out of order relative to other tasks on the same executor.
2015-11-20 09:30:35 -08:00
Dmitry Spikhalskiy
2a65ae256e [#4331] Helper methods to get charset from Content-Type header of HttpMessage
Motivation:

HttpHeaders already has specific methods for such popular and simple headers like "Host", but if I need to convert POST raw body to string I need to parse complex ContentType header in my code.

Modifications:

Add getCharset and getCharsetAsString methods to parse charset from Content-Length header.

Result:

Easy to use utility method.
2015-11-19 15:59:34 -08:00
Scott Mitchell
b4b791353d AsciiString optimized hashCode
Motivation:
The AsciiString.hashCode() method can be optimized. This method is frequently used while to build the DefaultHeaders data structure.

Modification:
- Add a PlatformDependent hashCode algorithm which utilizes UNSAFE if available

Result:
AsciiString hashCode is faster.
2015-11-10 10:28:31 -08:00
Vladimir Krivosheev
a4f3e72e71 configurable service thread name prefix
Motivation:

If netty used as part of application, should be a way to prefix service thread name to easy distinguish such threads (for example, used in IntelliJ Platform)

Modifications:

Introduce system property io.netty.serviceThreadPrefix

Result:

ThreadDeathWatcher thread has a readable name "Netty threadDeathWatcher-2-1" if io.netty.serviceThreadPrefix set to "Netty"
2015-11-05 08:51:12 +01:00
Scott Mitchell
19658e9cd8 HTTP/2 Headers Type Updates
Motivation:
The HTTP/2 RFC (https://tools.ietf.org/html/rfc7540#section-8.1.2) indicates that header names consist of ASCII characters. We currently use ByteString to represent HTTP/2 header names. The HTTP/2 RFC (https://tools.ietf.org/html/rfc7540#section-10.3) also eludes to header values inheriting the same validity characteristics as HTTP/1.x. Using AsciiString for the value type of HTTP/2 headers would allow for re-use of predefined HTTP/1.x values, and make comparisons more intuitive. The Headers<T> interface could also be expanded to allow for easier use of header types which do not have the same Key and Value type.

Motivation:
- Change Headers<T> to Headers<K, V>
- Change Http2Headers<ByteString> to Http2Headers<CharSequence, CharSequence>
- Remove ByteString. Having AsciiString extend ByteString complicates equality comparisons when the hash code algorithm is no longer shared.

Result:
Http2Header types are more representative of the HTTP/2 RFC, and relationship between HTTP/2 header name/values more directly relates to HTTP/1.x header names/values.
2015-10-30 15:29:44 -07:00
Trustin Lee
d0f3cd383d Fix a bug where DefaultPromise.toString() says 'incomplete' when it's done
Motivation:

DefaultPromise.toString() returns 'DefaultPromise(incomplete)' when it's
actually complete with non-null result.

Modifications:

Handle the case where the promise is done and its result is non-null in
toString()

Result:

The String returned by DefaultPromise.toString() is not confusing
anymore.
2015-10-30 08:12:18 +01:00
Norman Maurer
a47685b243 Use bitwise operation when sampling for resource leak detection.
Motivation:

Modulo operations are slow, we can use bitwise operation to detect if resource leak detection must be done while sampling.

Modifications:

- Ensure the interval is a power of two
- Use bitwise operation for sampling
- Add benchmark.

Result:

Faster sampling.
2015-10-29 19:18:44 +01:00
Scott Mitchell
ed98cd8200 DefaultPromise StackOverFlowException
Motivation:
When the ImmediateEventExecutor is in use it is possible to get a StackOverFlowException if when a promise completes a new listener is added to that promise.

Modifications:
- Protect against the case where LateListeners.run() smashes the stack.

Result:
Fixes https://github.com/netty/netty/issues/4395
2015-10-29 11:10:57 -07:00
Norman Maurer
7d4c077492 Add *UnsafeHeapByteBuf for improve performance on systems with sun.misc.Unsafe
Motivation:

sun.misc.Unsafe allows us to handle heap ByteBuf in a more efficient matter. We should use special ByteBuf implementation when sun.misc.Unsafe can be used to increase performance.

Modifications:

- Add PooledUnsafeHeapByteBuf and UnpooledUnsafeHeapByteBuf that are used when sun.misc.Unsafe is ready to use.
- Add UnsafeHeapSwappedByteBuf

Result:

Better performance when using heap buffers and sun.misc.Unsafe is ready to use.
2015-10-21 09:04:13 +02:00
Norman Maurer
f30a51b905 Correctly handle byte shifting if system does not support unaligned access.
Motivation:

We had a bug in our implemention which double "reversed" bytes on systems which not support unaligned access.

Modifications:

- Correctly only reverse bytes if needed.
- Share code between unsafe implementations.

Result:

No more data-corruption on sytems without unaligned access.
2015-10-20 17:32:13 +02:00
Norman Maurer
b7e947709e [#4357] Fix possible assert error in GlobalEventExecutor
Motivation:

We started the thread before store it in a field which could lead to an assert error when the thread is executed before we actually store it.

Modifications:

Store thread before start it.

Result:

No more assert error possible.
2015-10-16 20:56:25 +02:00
Norman Maurer
11e8163aa9 [#4284] Forward decoded messages more frequently
Motivation:

At the moment we only forward decoded messages that were added the out List once the full decode loop was completed. This has the affect that resources may not be released as fast as possible and as an application may incounter higher latency if the user triggeres a writeAndFlush(...) as a result of the decoded messages.

Modifications:

- forward decoded messages after each decode call

Result:

Forwarding decoded messages through the pipeline in a more eager fashion.
2015-10-07 14:15:53 +02:00
Scott Mitchell
d4680c55d8 AsciiString contains utility methods
Motivation:
When dealing with case insensitive headers it can be useful to have a case insensitive contains method for CharSequence.

Modifications:
- Add containsCaseInsensative to AsciiString

Result:
More expressive utility method for case insensitive CharSequence.
2015-10-02 12:50:11 -07:00
Scott Mitchell
c7e3f6c6fd HTTP/2 defines using String instead of CharSequence
Motivation:
Http2CodecUtils has some static variables which are defined as Strings instead of CharSequence. One of these defines is used as a header name and should be AsciiString.

Modifications:
- Change the String defines in Http2CodecUtils to CharSequence

Result:
Types are more consistently using CharSequence and adding the upgrade header will require less work.
2015-09-16 14:55:33 -07:00
Matteo Merli
9b45e9d015 Additional configuration for leak detection
Motivation:

Leak detector, when it detects a leak, will print the last 5 stack
traces that touched the ByteBuf. In some cases that might not be enough
to identify the root cause of the leak.
Also, sometimes users might not be interested in tracing all the
operations on the buffer, but just the ones that are affecting the
reference count.

Modifications:

Added command line properties to override default values:
 * Allow to configure max number of stack traces to collect
 * Allow to only record retain/release operation on buffers

Result:
Users can increase the number of stack traces to debug buffer leaks
with lot of retain/release operations.
2015-08-30 20:50:10 +02:00
Norman Maurer
6d473e7f39 Allow to get details of the Thread that powers a SingleThreadEventExecutor.
Motivation:

for debugging and metrics reasons its sometimes useful to be able to get details of the the Thread that powers a SingleThreadEventExecutor.

Modifications:

- Expose ThreadProperties
- Add unit test.

Result:

It's now possible to get details of the Thread that powers a SingleThreadEventExecutor.
2015-08-28 15:34:19 +02:00
Norman Maurer
1a9ea2d349 [#4147] Allow to disable recycling
Motivation:

Sometimes it is useful to disable recycling completely if memory constraints are very tight.

Modifications:

Allow to use -Dio.netty.recycler.maxCapacity=0 to disable recycling completely.

Result:

It's possible to disable recycling now.
2015-08-28 15:05:17 +02:00
Norman Maurer
eb1c97b3b9 [#4110] Correct javadocs of MpscLinkedQueue
Motivation:

The javadocs are incorrect and so give false impressions of use-pattern.

Modifications:

- Fix javadocs of which operations are allowed from multiple threads concurrently.
- Let isEmpty() work concurrently.

Result:

Correctly document usage-patterns.
2015-08-27 09:09:28 +02:00
Scott Mitchell
cbc38e938a UNSAFE.throwException null arg crashes JVM
Motivation:
It has been observed that passing a null argument to Unsafe.throwException can crash the JVM.

Modifications:
- PlatformUnsafe0.throwException should honor http://docs.oracle.com/javase/specs/jls/se8/html/jls-14.html#jls-14.18 and throw a NPE

Result:
No risk of JVM crashing for null argument.
Fixes https://github.com/netty/netty/issues/4131
2015-08-26 23:50:51 -07:00
Scott Mitchell
9bc322a6a8 StringUtil not closing Formatter
Motivation:
The StringUtil class creates a Formatter object, but does not close it. There are also a 2 utility methods which would be generally useful.

Modifications:
- Close the Formatter
- Add length and isNullOrEmpty

Result:
No more resource leaks. Additional utility methods.
2015-08-20 09:44:31 -07:00
Scott Mitchell
ba6ce5449e Headers Performance Boost and Interface Simplification
Motivation:
A degradation in performance has been observed from the 4.0 branch as documented in https://github.com/netty/netty/issues/3962.

Modifications:
- Simplify Headers class hierarchy.
- Restore the DefaultHeaders to be based upon DefaultHttpHeaders from 4.0.
- Make various other modifications that are causing hot spots.

Result:
Performance is now on par with 4.0.
2015-08-17 08:50:11 -07:00
Jakob Buchgraber
6fd0a0c55f Faster and more memory efficient headers for HTTP, HTTP/2, STOMP and SPYD. Fixes #3600
Motivation:

We noticed that the headers implementation in Netty for HTTP/2 uses quite a lot of memory
and that also at least the performance of randomly accessing a header is quite poor. The main
concern however was memory usage, as profiling has shown that a DefaultHttp2Headers
not only use a lot of memory it also wastes a lot due to the underlying hashmaps having
to be resized potentially several times as new headers are being inserted.

This is tracked as issue #3600.

Modifications:
We redesigned the DefaultHeaders to simply take a Map object in its constructor and
reimplemented the class using only the Map primitives. That way the implementation
is very concise and hopefully easy to understand and it allows each concrete headers
implementation to provide its own map or to even use a different headers implementation
for processing requests and writing responses i.e. incoming headers need to provide
fast random access while outgoing headers need fast insertion and fast iteration. The
new implementation can support this with hardly any code changes. It also comes
with the advantage that if the Netty project decides to add a third party collections library
as a dependency, one can simply plug in one of those very fast and memory efficient map
implementations and get faster and smaller headers for free.

For now, we are using the JDK's TreeMap for HTTP and HTTP/2 default headers.

Result:

- Significantly fewer lines of code in the implementation. While the total commit is still
  roughly 400 lines less, the actual implementation is a lot less. I just added some more
  tests and microbenchmarks.

- Overall performance is up. The current implementation should be significantly faster
  for insertion and retrieval. However, it is slower when it comes to iteration. There is simply
  no way a TreeMap can have the same iteration performance as a linked list (as used in the
  current headers implementation). That's totally fine though, because when looking at the
  benchmark results @ejona86 pointed out that the performance of the headers is completely
  dominated by insertion, that is insertion is so significantly faster in the new implementation
  that it does make up for several times the iteration speed. You can't iterate what you haven't
  inserted. I am demonstrating that in this spreadsheet [1]. (Actually, iteration performance is
  only down for HTTP, it's significantly improved for HTTP/2).

- Memory is down. The implementation with TreeMap uses on avg ~30% less memory. It also does not
  produce any garbage while being resized. In load tests for GRPC we have seen a memory reduction
  of up to 1.2KB per RPC. I summarized the memory improvements in this spreadsheet [1]. The data
  was generated by [2] using JOL.

- While it was my original intend to only improve the memory usage for HTTP/2, it should be similarly
  improved for HTTP, SPDY and STOMP as they all share a common implementation.

[1] https://docs.google.com/spreadsheets/d/1ck3RQklyzEcCLlyJoqDXPCWRGVUuS-ArZf0etSXLVDQ/edit#gid=0
[2] https://gist.github.com/buchgr/4458a8bdb51dd58c82b4
2015-08-04 17:12:24 -07:00
Ning Sun
9236a8d156 (fix) typo 2015-07-30 12:49:25 +02:00
Scott Mitchell
a7713069a1 HttpObjectDecoder performance improvements
Motivation:
The HttpObjectDecoder is on the hot code path for the http codec. There are a few hot methods which can be modified to improve performance.

Modifications:
- Modify AppendableCharSequence to provide unsafe methods which don't need to re-check bounds for every call.
- Update HttpObjectDecoder methods to take advantage of new AppendableCharSequence methods.

Result:
Peformance boost for decoding http objects.
2015-07-29 23:26:26 -07:00
Daniel Darabos
623d9d7202 Fix typo in warning message. 2015-07-29 18:38:33 +02:00
nmittler
296649cfc8 Make PrimitiveCollections generated for all primitive maps.
Motivation:

We should support XXXCollections methods for all primitive map types.

Modifications:

Removed PrimitiveCollections and added a template for XXXCollections.

Result:

Fixes #4001
2015-07-27 06:59:23 -07:00
nmittler
93fc3c6e45 Make IntObjectHashMap extend Map
Motivation:

It would be useful to support the Java `Map` interface in our primitive maps.

Modifications:

Renamed current methods to "pXXX", where p is short for "primitive". Made the template for all primitive maps extend the appropriate Map interface.

Result:

Fixes #3970
2015-07-22 15:52:27 -07:00
Norman Maurer
05dae57ad7 Ensure cancelled scheduled tasks can be GC'ed ASAP
Motivation:

Prior we used a purge task that would remove previous canceled scheduled tasks from the internal queue. This could introduce some delay and so use a lot of memory even if the task itself is already canceled.

Modifications:

Schedule removal of task from queue via EventLoop if cancel operation is not done in the EventLoop Thread or just remove directly if the Thread that cancels the scheduled task is in the EventLoop.

Result:

Faster possibility to GC a canceled ScheduledFutureTask.
2015-07-19 16:51:12 +02:00
Norman Maurer
81fee66c78 Let PoolThreadCache work even if allocation and deallocation Thread are different
Motivation:

PoolThreadCache did only cache allocations if the allocation and deallocation Thread were the same. This is not optimal as often people write from differen thread then the actual EventLoop thread.

Modification:

- Add MpscArrayQueue which was forked from jctools and lightly modified.
- Use MpscArrayQueue for caches and always add buffer back to the cache that belongs to the allocation thread.

Result:

ThreadPoolCache is now also usable and so gives performance improvements when allocation and deallocation thread are different.

Performance when using same thread for allocation and deallocation is noticable worse then before.
2015-05-27 14:38:11 +02:00
Norman Maurer
08d234cdf0 [#3805] Fix incorrect javadoc in PlatformDependent 2015-05-25 21:42:31 +02:00
Norman Maurer
271af7c624 Expose metrics for PooledByteBufAllocator
Motivation:

The PooledByteBufAllocator is more or less a black-box atm. We need to expose some metrics to allow the user to get a better idea how to tune it.

Modifications:

- Expose different metrics via PooledByteBufAllocator
- Add *Metrics interfaces

Result:

It is now easy to gather metrics and detail about the PooledByteBufAllocator and so get a better understanding about resource-usage etc.
2015-05-20 21:06:17 +02:00
Norman Maurer
e71e40057f Fix possible IllegalStateException caused by closeNotifyTimeout when using SslHandler
Motivation:

In the SslHandler we schedule a timeout at which we close the Channel if a timeout was detected during close_notify. Because this can race with notify the flushFuture we can see an IllegalStateException when the Channel is closed.

Modifications:

- Use a trySuccess() and tryFailure(...) to guard against race.

Result:

No more race.
2015-05-06 21:50:16 +02:00
yz_liu
488d905598 fix a typo in RecyclableArrayList 2015-05-06 09:07:48 +02:00
Norman Maurer
cf66edb3a1 [#3675] Fix livelock issue in MpscLinkedQueue
Motivation:

All read operations should be safe to execute from multiple threads which was not the case and so could produce a livelock.

Modifications:

Modify methods so these are safe to be called from multiple threads.

Result:

No more livelock.
2015-05-06 06:21:14 +02:00
Trustin Lee
63a02fc04e Revamp DNS codec
Motivation:

There are various known issues in netty-codec-dns:

- Message types are not interfaces, which can make it difficult for a
  user to implement his/her own message implementation.
- Some class names and field names do not match with the terms in the
  RFC.
- The support for decoding a DNS record was limited. A user had to
  encode and decode by him/herself.
- The separation of DnsHeader from DnsMessage was unnecessary, although
  it is fine conceptually.
- Buffer leak caused by DnsMessage was difficult to analyze, because the
  leak detector tracks down the underlying ByteBuf rather than the
  DnsMessage itself.
- DnsMessage assumes DNS-over-UDP.
- To send an EDNS message, a user have to create a new DNS record class
  instance unnecessarily.

Modifications:

- Make all message types interfaces and add default implementations
- Rename some classes, properties, and constants to match the RFCs
  - DnsResource -> DnsRecord
  - DnsType -> DnsRecordType
  - and many more
- Remove DnsClass and use an integer to support EDNS better
- Add DnsRecordEncoder/DnsRecordDecoder and their default
  implementations
  - DnsRecord does not require RDATA to be ByteBuf anymore.
  - Add DnsRawRecord as the catch-all record type
- Merge DnsHeader into DnsMessage
- Make ResourceLeakDetector track AbstractDnsMessage
- Remove DnsMessage.sender/recipient properties
  - Wrap DnsMessage with AddressedEnvelope
  - Add DatagramDnsQuest and DatagramDnsResponse for ease of use
  - Rename DnsQueryEncoder to DatagramDnsQueryEncoder
  - Rename DnsResponseDecoder to DatagramDnsResponseDecoder
- Miscellaneous changes
  - Add StringUtil.TAB

Result:

- Cleaner APi
- Can support DNS-over-TCP more easily in the future
- Reduced memory footprint in the default DnsQuery/Response
  implementations
- Better leak tracking for DnsMessages
- Possibility to introduce new DnsRecord types in the future and provide
  full record encoder/decoder implementation.
- No unnecessary instantiation for an EDNS pseudo resource record
2015-05-01 11:33:16 +09:00