- Rename capacity variables to reqCapacity or normCapacity to distinguish if its the request capacity or the normalized capacity
- Do not reallocate on ByteBuf.capacity(int) if reallocation is unnecessary; just update the index range.
- Revert the workaround in DefaultChannelHandlerContext
- Also fixed a incorrect port of SpdySessionHandler
- Previously, it closed the connection too early when sending a GOAWAY frame
- After this fix, SpdySessionHandlerTest now passes again without the previous fix
- Fixes#831
This commit ensures the following events are never triggered as a direct
invocation if they are triggered via ChannelPipeline.fire*():
- channelInactive
- channelUnregistered
- exceptionCaught
This commit also fixes the following issues surfaced by this fix:
- Embedded channel implementations run scheduled tasks too early
- SpdySessionHandlerTest tries to generate inbound data even after the
channel is closed.
- AioSocketChannel enters into an infinite loop on I/O error.
- Fixes#826
Unsafe.isFreed(), free(), suspend/resumeIntermediaryAllocations() are not that dangerous. internalNioBuffer() and internalNioBuffers() are dangerous but it seems like nobody is using it even inside Netty. Removing those two methods also removes the necessity to keep Unsafe interface at all.
This commit also introduce a new interface which is called AioSocketChannelConfig to expose AIO only config options with the right visibility.
Also it change the ChannelConfig.setAllocator(..) to return the ChannelConfig to be more consistent with the other methods.
This pull request introduces the new default ByteBufAllocator implementation based on jemalloc, with a some differences:
* Minimum possible buffer capacity is 16 (jemalloc: 2)
* Uses binary heap with random branching (jemalloc: red-black tree)
* No thread-local cache yet (jemalloc has thread-local cache)
* Default page size is 8 KiB (jemalloc: 4 KiB)
* Default chunk size is 16 MiB (jemalloc: 2 MiB)
* Cannot allocate a buffer bigger than the chunk size (jemalloc: possible) because we don't have control over memory layout in Java. A user can work around this issue by creating a composite buffer, but it's not always a feasible option. Although 16 MiB is a pretty big default, a user's handler might need to deal with the bounded buffers when the user wants to deal with a large message.
Also, to ensure the new allocator performs good enough, I wrote a microbenchmark for it and made it a dedicated Maven module. It uses Google's Caliper framework to run and publish the test result (example)
Miscellaneous changes:
* Made some ByteBuf implementations public so that those who implements a new allocator can make use of them.
* Added ByteBufAllocator.compositeBuffer() and its variants.
* ByteBufAllocator.ioBuffer() creates a buffer with 0 capacity.
testConcurrentMessageBufferAccess() assumes the outbound/inbound byte buffers are unbounded. Because PooledByteBuf is bounded, the test did not pass.
The fix makes an assumption that ctx.flush() or fireInboundBufferUpdated() will make the next buffer consumed immediately, which is not the case in the real world. Under network congestion, a user will see IndexOutOfBoundsException if the user's handler implementation writes boundlessly into inbound/outbound buffers.
* UnsafeByteBuf is gone. I added ByteBuf.unsafe() back.
* To avoid extra instantiation, all ByteBuf implementations implement the ByteBuf.Unsafe interface.
* To hide this implementation detail, all ByteBuf implementations are package-private.
* AbstractByteBuf and SwappedByteBuf are public and they do not implement ByteBuf.Unsafe because they don't need to.
* unwrap() is not an unsafe operation anymore.
* ChannelBuf also has unsafe() and Unsafe. ByteBuf.Unsafe extends ChannelBuf.unsafe(). ChannelBuf.unsafe() provides free() operation so that a user does not need to down-cast the buffer in freeInbound/OutboundBuffer().
To perform writes in AioSocketChannel, we get a ByteBuffer view of the
outbound buffer and specify it as a parameter when we call
AsynchronousSocketChannel.write().
In most cases, the write() operation is finished immediately. However,
sometimes, it is scheduled for later execution. In such a case, there's
a chance for a user's handler to append more data to the outbound
buffer.
When more data is appended to the outbound buffer, the outbound buffer
can expand its capacity by itself. Changing the capacity of a buffer is
basically made of the following steps:
1. Allocate a larger new internal memory region.
2. Copy the current content of the buffer to the new memory region.
3. Rewire the buffer so that it refers to the new region.
4. Deallocate the old memory region.
Because the old memory region is deallocated at the step 4, the write
operation scheduled later will access the deallocated region, leading
all sort of data corruption or even segfaults.
To prevent this situation, I added suspendIntermediaryDeallocations()
and resumeIntermediaryDeallocations() to UnsafeByteBuf.
AioSocketChannel.doFlushByteBuf() now calls suspendIntermediaryDealloc()
to defer the deallocation of the old memory regions until the completion
handler is notified.
An AssertionError is triggered by a ByteBuf when beginRead() attempts to
access the buffer which has been freed already. This commit ensures the
buffer is not freed before performing an I/O operation.
To determine if the buffer has been freed, UnsafeByteBuf.isFreed() has
been added.
After some debugging, I found that JDK AIO implementation often performs
I/O immediately from the caller thread if the caller thread is the I/O
thread, and notifies the completion handler also immediately. This
commit handles such a case correctly during reads and writes.
Additionally, this commit also changes SingleThreadEventExecutor to let
it handle unexpected exceptions such as AssertionError in a robus
manner.
When a Netty application shuts down, a user often sees a REE
(RejectedExecutionException).
A REE is raised due to various reasons we don't have control over, such
as:
- A client connects to a server while the server is shutting down.
- An event is triggered for a closed Channel while its event loop is
also shutting down. Some of them are:
- channelDeregistered (triggered after a channel is closed)
- freeIn/OutboundBuffer (triggered after channelDeregistered)
- userEventTriggered (triggered anytime)
To address this issue, a new method called confirmShutdown() has been
added to SingleThreadEventExecutor. After a user calls shutdown(),
confirmShutdown() runs any remaining tasks in the task queue and ensures
no events are triggered for last 2 seconds. If any task are added to
the task queue before 2 seconds passes, confirmShutdown() prevents the
event loop from terminating by returning false.
Now that SingleThreadEventExecutor needs to accept tasks even after
shutdown(), its execute() method only rejects the task after the event
loop is terminated (i.e. isTerminated() returns true.) Except that,
there's no change in semantics.
SingleThreadEventExecutor also checks if its subclass called
confirmShutdown() in its run() implementation, so that Netty developers
can make sure they shut down their event loop impementation correctly.
It also fixes a bug in AioSocketChannel, revealed by delayed shutdown,
where an inboundBufferUpdated() event is triggered on a closed Channel
with deallocated buffers.
Caveats:
Because SingleThreadEventExecutor.takeTask() does not have a notion of
timeout, confirmShutdown() adds a dummy task (WAKEUP_TASK) to wake up
takeTask() immediately and instead sleeps hard-coded 100ms. I'll
address this issue later by modifying takeTask() times out dynamically.
Miscellaneous changes:
SingleThreadEventExecutor.wakeup() now has the default implementation.
Instead of interrupting the current thread, it simply adds a dummy task
(WAKEUP_TASK) to the task queue, which is more elegant and efficient.
NioEventLoop is the only implementation that overrides it. All other
implementations' wakeup()s were removed thanks to this change.
This commit introduces a new API for ByteBuf allocation which fixes
issue #643 along with refactoring of ByteBuf for simplicity and better
performance. (see #62)
A user can configure the ByteBufAllocator of a Channel via
ChannelOption.ALLOCATOR or ChannelConfig.get/setAllocator(). The
default allocator is currently UnpooledByteBufAllocator.HEAP_BY_DEFAULT.
To allocate a buffer, do not use Unpooled anymore. do the following:
ctx.alloc().buffer(...); // allocator chooses the buffer type.
ctx.alloc().heapBuffer(...);
ctx.alloc().directBuffer(...);
To deallocate a buffer, use the unsafe free() operation:
((UnsafeByteBuf) buf).free();
The following is the list of the relevant changes:
- Add ChannelInboundHandler.freeInboundBuffer() and
ChannelOutboundHandler.freeOutboundBuffer() to let a user free the
buffer he or she allocated. ChannelHandler adapter classes implement
is already, so most users won't need to call free() by themselves.
freeIn/OutboundBuffer() methods are invoked when a Channel is closed
and deregistered.
- All ByteBuf by contract must implement UnsafeByteBuf. To access an
unsafe operation: ((UnsafeByteBuf) buf).internalNioBuffer()
- Replace WrappedByteBuf and ByteBuf.Unsafe with UnsafeByteBuf to
simplify overall class hierarchy and to avoid unnecesary instantiation
of Unsafe instances on an unsafe operation.
- Remove buffer reference counting which is confusing
- Instantiate SwappedByteBuf lazily to avoid instantiation cost
- Rename ChannelFutureFactory to ChannelPropertyAccess and move common
methods between Channel and ChannelHandlerContext there. Also made it
package-private to hide it from a user.
- Remove unused unsafe operations such as newBuffer()
- Add DetectionUtil.canFreeDirectBuffer() so that an allocator decides
which buffer type to use safely
- Add Bootstrap.attr() and ServerBootstrap.attr()/childAttr() so that a
user can initialize the attribute map from the beginning.
- Replace newBootstrap() with duplicate()
- Ensure the event loop threads are never terminated before all tasks
submitted by JDK are executed
- Close all open connections before terminating an event loop
- Add ChannelOption.ALLOW_HALF_CLOSURE
- If true, ChannelInputShutdownEvent is fired via userEventTriggered()
when the remote peer shuts down its output, and the connection is
not closed until a user calls close() explicitly.
- If false, the connection is closed immediately as it did before.
- Add SocketChannel.isInputShutdown()
- Add & improve test cases related with half-closed sockets
- Use copy-on-write map
- Fix a potential bug where the old implementation assumed that one
Runnable type always wraps the same Runnable
- Cache offset value instead of Field in UnsafeAioChannelFinder
- Reimplemented the test
- Fixed various bugs related with read/accept suspension found while testing
- defaultInterestOps of NioServerSocketChannel should be OP_ACCEPT
- There's no need do deregister and re-register to suspend/resume accept()
- Occational infinite loop with 100% CPU consumption in OioEventLoop, caused by OioSocketChannel
- Even if read/accept is suspended, what's read or accepted should be notified to a user
- Clean up
- Do not stop reading when reached at maxCapacity.
- Just let handler drain the buffer and try again quickly.
- No more magic number in OIO buffer expansion
- Remove polling in SingleThreadEventExecutor
- Create a dedicated scheduled task scheduler called 'TaskScheduler'
- TaskScheduler is created per EventLoopGroup / EventExecutorGroup
- SingleThreadEventExecutor delegates all scheduled execution requests
to TaskScheduler provided as a constructor parameter
- TaskScheduler is a specialized form of single threaded
ScheduledExecutorService which requires an EventExecutor as a
parameter for all requests.
o Add ByteBuf.hasNioBuffers() method
o Promote CompositeByteBuf.nioBuffers() methods to ByteBuf
o Use ByteBuf.nioBuffers() methods from AioSocketChannel
- Add EventExecutorGroup and EventLoopGroup
- EventExecutor and EventLoop extends EventExecutorGroup and
EventLoopGroup
- They form their own group so that .next() returns itself.
- Rename Bootstrap.eventLoop() to group()
- Rename parameter names such as executor to group
- Rename *EventLoop/Executor to *EventLoop/ExecutorGroup
- Rename *ChildEventLoop/Executor to *EventLoop/Executor
- Replace ByteBufferBackedByteBuf with DirectByteBuf
- Make DirectByteBuf and HeapByteBuf dynamic
- Remove DynamicByteBuf
- Replace Unpooled.dynamicBuffer() with Unpooled.buffer() and
directBuffer()
- Remove ByteBufFactory (will be replaced with ByteBufPool later)
- Add ByteBuf.Unsafe (might change in the future)
- Removed VoidEnum because a user can now specify Void instead
- AIO: Prefer discardReadBytes to clear
- AIO: Fixed a potential bug where notifyFlushFutures() is not called
if flush() was requested with no outbound data
- Used reflection hack to dispatch the tasks submitted by JDK
efficiently. Without hack, there's higher chance of additional
context switches.
- Server side performance improved to the expected level.
- Client side performance issue still under investigation
- Add Channel.metadata() and remove Channel.bufferType()
- DefaultPipeline automatically redirects disconnect() request to
close() if the channel has no disconnect operation
- Remove unnecessary disconnect() implementations
- ChannelInboundHandler and ChannelOutboundHandler does not have a type
parameter anymore.
- User should implement ChannelInboundMessageHandler or
ChannelOutboundMessageHandler.
- Add MessageBuf which replaces java.util.Queue
- Add ChannelBuf which is common type of ByteBuf and ChannelBuf
- ChannelBuffers was renamed to ByteBufs
- Add MessageBufs
- All these changes are going to replace ChannelBufferHolder.
- ChannelBuffer gives a perception that it's a buffer of a
channel, but channel's buffer is now a byte buffer or a message
buffer. Therefore letting it be as is is going to be confusing.
- Also prohibited a user from overriding
ChannelInbound(Byte|Message)HandlerAdapter. If a user wants to do
that, he or she should extend ChannelInboundHandlerAdapter instead.
- In computing, 'stream' means both byte stream and message stream,
which is confusing.
- Also, we were already mixing stream and byte in some places and
it's better use the terms consistently.
(e.g. inboundByteBuffer & inbound stream)
- SslHandler always begins handshake unless startTls is true
- Removed issueHandshake property
- If a user wants to start handshake later, he/she has to add
SslHandler later.
- Removed enableRenegotiation property
- JDK upgrade fixes the security vulnerability - no need to complicate
our code
- Some property name changes
- getSSLEngineInboundCloseFuture() -> sslCloseFuture()
- Updated securechat example
- Added timeout for handshake and close_notify for better security
- However, it's currently hard-coded. Will make it a property later.
- Some tests like SpdySessionHandlerTest accesses outbound buffer
even before the outbound buffer is initialized by
AbstractEmbeddedChannel's subclasses, leading to NPE at <init>.
To fix this problem, subclasses now pass the outbound buffer as
a constructor parameter to AbstractEmbeddedChannel.
- Added EventExecutor.inEventLoop(Thread) and replaced executor identity
comparison in DefaultChannelPipeline with it - more elegant IMO
- Removed the test classes that needs rewrite or is of no use
- LoggingHandler now only logs state and operations
- StreamLoggingHandler and MessageLoggingHandler log the buffer content
- Added ChannelOperationHandlerAdapter
- Used by WriteTimeoutHandler
- Extracted some handler methods from ChannelInboundHandler into
ChannelStateHandler
- Extracted some handler methods from ChannelOutboundHandler into
ChannelOperationHandler
- Moved exceptionCaught and userEventTriggered are now in
ChannelHandler
- Channel(Inbound|Outbound)HandlerContext is merged into
ChannelHandlerContext
- ChannelHandlerContext adds direct access methods for inboud and
outbound buffers
- The use of ChannelBufferHolder is minimal now.
- Before: inbound().byteBuffer()
- After: inboundByteBuffer()
- Simpler and better performance
- Bypass buffer types were removed because it just does not work at all
with the thread model.
- All handlers that uses a bypass buffer are broken. Will fix soon.
- CombinedHandlerAdapter does not make sense anymore either because
there are four handler interfaces to consider and often the two
handlers will implement the same handler interface such as
ChannelStateHandler. Thinking of better ways to provide this feature
- DefaultChannelPipeline detects such cases and creates an object called
'bridge' that works as a man-in-the-middle to deal with a race
condition
- Slight performance drop is observed but still faster than v3.
Couldn't find much from a profiler yet.
- Previously, head was a volatile field which is null at the beginning.
While iterating over the pipeline, if the loop hits null, it called
Channel.Unsafe explicitly.
- Instead, I created an outbound handler that redirects all requests
to the unsafe and made it a final field of the pipeline.
- As a result, DefaultChannelPipeline code became much simpler.
- SocketTestCombination generates all possible test combinations of
socket transports.
- SocketEchoTest iterates over the combinations and runs all tests
using reflection.
- The handler you specify with initializer() is actually simply added
to the pipeline and that's all. It's ChannelInitializer which does
additional work. For example, a user can specify just a single
handler with initializer() and it will still work. This is especially
common for Bootstrap, so I renamed initializer to handler, which makes
more sense.
- DefaultChannelPipeline uses this information to reject invalid buffer
access in inbound(Message|Byte)Buffer. Otherwise, a user can access
a message buffer when the channel is stream-oriented.
- Because ChannelType cannot be both STREAM and MESSAGE, catch-all
buffer has been removed to avoid confusion and unexpected behavior
(it's already causing headache.)
- As a result, codec embedder needs rework.
... just like we do with byte arrays. toByteBuffer() and
toByteBuffers() had an indeterministic behavior and thus it could not
tell when the returned NIO buffer is shared or not. nioBuffer() always
returns a view buffer of the Netty buffer. The only case where
hasNioBuffer() returns false and nioBuffer() fails is the
CompositeChannelBuffer, which is not very commonly used and *slow*.
- Add EventExecutor and make EventLoop extend it
- Add SingleThreadEventExecutor and MultithreadEventExecutor
- Add EventExecutor's default implementation
- Fixed an API design problem where there is no way to get non-bypass
buffer of desired type
- Add ChannelHandlerContext.eventLoop() for convenience
- Bootstrap and ServerBootstrap handles channel initialization failure
better
- More strict checks for missing @Sharable annotation
- A handler without @Sharable annotation cannot be added more than
once now.
- Added a new convenience method to ChannelInboundstreamHandlerAdapter
- EchoServerHandler uses the new method
- DefaultChannelPipeline calls inboundByteBuffer.discardReadBytes()
when it is sure there's no memory copy involved
- Really attempt to create a queue to determine LTQ can be initialized
in runtime, and cache the result
- Remove unnecessary Class<T> parameter in createQueue()
- Remove unused createQueue(Collection)
- LocalChannel and LocalServerChannel uses it to close themselves on
shutdown
- LocalEcho example does not call close() anymore because the channels
are closed automatically on shutdown
- Exception in this case makes a user less confusing
- To reduce the overhead of filling the stack trace,
NoSuchBufferException has a public pre-constructed instance.
- This is necessary because codec framework sometimes need to support
both type of outbound buffers.
- Fixed a bug where SpdyFrameEncoder did not handle ping messages
- Reduced memory copy in codec embedder (EmbeddedChannel)
- Renamed ChannelBootstrap to Bootstrap
- Renamed ServerChannelBootstrap to ServerBootstrap
- Moved bootstrap classes to io.netty.bootstrap as before
- Moved unfoldAndAdd() to a separate utility class
- Fixed a bug in unfoldAndAdd() where it did not handle ChannelBuffer
correctly
- Previous API did not support the pipeline which contains multiple
MessageToStreamEncoders because there was no way to find the closest
outbound byte buffer. Now you always get the correct buffer even if
the handler that provides the buffer is placed distantly.
For example:
Channel -> MsgAEncoder -> MsgBEncoder -> MsgCEncoder
Msg(A|B|C)Encoder will all have access to the channel's outbound
byte buffer. Previously, it was simply impossible.
- Improved ChannelBufferHolder.toString()
- AbstractChannel.doRead() is split into two versions so that the
implementation doesn't have to validate the buffer type.
- Optimized ChannelBufferHolder a little bit
- Reduced GC related with flush future notification
- Added FlushCheckpoint and DefaultChannelFuture implements it
opportunistically
-
- AbstractChannel now handles flushing a message buffer
- Cleaned up DatagramChannel interface
- Removed ProtocolFamily because a user can create an NIO
DatagramChannel and specify it as a constructor parameter
- UniqueName and UniqueKey constructors became public so that
I don't need to create a subclass every time.
- Replaced pipeline factories with initializers
- Ported essential parts related with HTTP to the new API
- Replaced ChannelHandlerAdapter.combine() with CombinedChannelHandler
- Fixed a bug where ReplayingDecoder does not notify the next handler
- Fixed a bug where ReplayingDecoder calls wrong callDecode() method
- Added a destination buffer as an argument to AbstractChannel.doRead()
for easier implementation
- Fixed a bug where NioSocketChannel did not try to increase the inbound
buffer size (moved the logic to AbstractChannel)
- UniqueKey removes the duplication between ChannelOption and
AttributeKey
- UniqueName provides common name collision check for AttributeKey,
ChannelOption, and Signal.
- Replaced ReplayError with Signal
- Replaced FrameDecoder and OneToOne(Encoder|Decoder) with:
- (Stream|Message)To(String|Message)(Encoder|Decoder)
- Moved the classes in 'codec.frame' up to 'codec'
- Fixed some bugs found while running unit tests
- It does not build a new Channel but just helps bootstrapping it.
- Added shutdown() method for simpler deinitialization
- ServerChannelBootstrap has shorter method names for the parent channel
- Added ChannelInitializer which is supposed to be used with the
builders
- Echo examples use ChannelBuilder and ServerChannelBuilder now
- Replace ChannelFuture.rethrowIfFailed() with sync*()
- Bug fixes
- AbstractChannel keeps the expected number of written bytes so that
the ChannelFuture of a flush() operation is notified on right timing.
- Added ChannelBufferHolder.size() to make this possible
- Added AbstractChannel.isCompatible() so that only compatible EventLoop
is accepted by a channel on registration
- Added ChannelOption to make channel options type-safe
- Moved writeSpinCount property to ChannelConfig and removed Nio*Config
- Miscellaneous cleanup
introducing
ChannelOption
- SingleThreadEventLoop now implements ScheduledExecutorService
- Scheduled tasks are automatically fetched into taskQueue by
pollTask() and takeTask()
- Removed MapBackedSet because Java 6 provides it
- Added ChannelBufferHolders.(inbound|outbound)BypassBuffer()
- The holder returned by these methods returns the next handler's
buffer. When a handler's new(Inbound|Outbound)Buffer returns
a bypass holder, your inboundBufferUpdated() and flush()
implementation should check if the buffer is a bypass and should not
modify the content of the buffer.
- Channel(Inbound|Outbound)?HandlerAdapter is now abstract.
- A user has to specify the exact inbound/outbound buffer type
- It's because there's no way to determine the best buffer type
- Implemented LoggingHandler using the new API.
- It doesn't dump received or sent messages yet.
- Fixed a bug where DefaultUnsafe.close() does not trigger deregister()
- Fixed a bug where NioSocketChannel.isActive() does not return false
when closed
- Made sure unnecessary interestOps are not OR'd
- Fixed a bug where DefaultChannelFuture.rethrowIfFailed() returns
silently if the future is not done yet - there's no ways to tell
the differences between failure and incompleteness.
- Optimized AbstractChannelBuffer.discardReadBytes()
- Split ChannelHandlerInvoker into ChannelInboundInvoker and
ChannelOutboundInvoker
- Channel implements ChannelOutboundInvoker
- ChannelOutboundInvoker.nextOut() is now out()
- ChannelOutboundHandlerContext.out() is now prevOut()
- Added the outbound operations without future
parameter to ChannelOutboundInvoker for user convenience
- All async operations which requires a ChannelFuture as a parameter
now returns ChannelFuture for user convenience
- Added ChannelFutureFactory.newVoidFuture() to allow a user specify
a dummy future that is of no use
- I'm unsure if it is actually a good idea to introduce it. It might
go away later.
- Made the contract of AbstractChannel.doXXX() much simpler and moved
all common code up to AbstractChannel.DefaultUnsafe
- Added Channel.isOpen()
- Fixed a bug where MultithreadEventLoop always shut down its child
event loops on construction
- Maybe more changes I don't remember :-)
- Remove large portion of code thanks to the new API
- SocketChannel implementations are instantiated without factories
- Retrofit the existing code with the new API
- Remove the classes and properties that are not necessary anymore
- Remove SingleThreadEventLoop.newRegistrationTask() and let
Channel.Unsafe handle registration by itself
- Channel.Unsafe.localAddress() and remoteAddress()
- JdkChannel is replaced by Channel.Unsafe.
- ChannelPipelineFactory will be replaced with sometime else when I
refactory the bootstrap package
- FileRegion is going away. A user can deregister a channel and perform
such operations by him/herself. If this turns out to be too
difficult, I'll introduce a new 'sendfile' operation to the outbound
handler.
- Channel now creates a ChannelPipeline by itself
I find no reason to allow a user to use one's own pipeline
implementation since I saw nobody does except for the cases where a
user wants to add a user attribute to a channel, which is now covered
by AttributeMap.
- Removed ChannelEvent and its subtypes because they are replaced by
direct method invocation.
- Replaced ChannelSink with Channel.unsafe()
- Various getter renaming (e.g. Channel.getId() -> Channel.id())
- Added ChannelHandlerInvoker interface
- Implemented AbstractChannel and AbstractServerChannel
- Some other changes I don't remember
- Add EventLoopException to wrap the exceptions while an event loop does
something
- Make EventLoop.register() return EventLoop so that the caller knows
the actual EventLoop that will handle the Channel even if the caller
called register() from MultithreadEventLoop
- Rename ChannelReader to ChannelInboundHandler
- Rename ChannelWriter to ChannelOutboundHandler
- Introduce ChannelBufferHolder instead of adding the common super type
of message buffers and byte buffers
- This is more type-safe and natural.
- Remove the notification methods for buffer closure (might add back
later when revisiting half-closed connection support)
- Merged LifeCycleAwareChannelHandler into ChannelHandler
- Replaced ChannelUpstreamHandler and ChannelDownstreamHandler with
ChannelReader and ChannelWriter
- These two new interfaces are much more type-safe than its ancestor.
- Simplified channel state model as described in #68
- Handler creates send/receive buffer.
- Previously, Netty created them, but it led to more memory copies and
inflexibility. I'm going to allow a handler to create a bounded
queue for example.
- It currently uses Queue<T> but I'll define a new interface and make
ChannelBuffer implement it (e.g. Queue<Byte>)
- Introduced AttributeMap which replaces attachments in Channel and
ChannelHandlerContext and ChannelLocal
