Commit Graph

6729 Commits

Author SHA1 Message Date
Louis Ryan
60c59f39af Use CoalescingBufferQueue to merge data writes on a stream in HTTP2 instead of CompositeByteBuf
Motivation:

Slicing a mutable CompositeByteBuf is not the appropriate mechanism to use to track and release buffers that have been written to a channel.
In particular buffers passed over an Embedded or LocalChannel are retained after the ChannelPromise is completed and listening to the
promise to consolidate a CompositeBuffer breaks slices taken from the composite as the offset indices have changed.

In addition CoalescingBufferQueue handles taking arbitrarily sized slices of a sequence of buffers more efficiently.

Modifications:

Convert FlowControlledData to use a CoalescingBufferQueue to handle merging data writes.

Result:

HTTP2 works over LocalChannel and code is considerably simpler.
2015-07-09 10:47:18 -07:00
zhangduo
e949dcd94f Allow numBytes == 0 when calling Http2LocalFlowController.consumeBytes.
Motivation:

Sometimes people use a data frame with length 0 to end a stream(such as jetty http2-server). So it is possible that data.readableBytes and padding are all 0 for a data frame, and cause an IllegalArgumentException when calling flowController.consumeBytes.

Modifications:

Return false when numBytes == 0 instead of throwing IllegalArgumentException.

Result:

Fix IllegalArgumentException.
2015-07-09 08:43:52 -07:00
Louis Ryan
cdbf43596d Add generic utility for enqueuing buffers with promises and dequeueing them in arbitrary byte ranges.
Motivation:
Simplifies writing code that needs to merge or slice a sequence of buffer & promise pairs into chunks of arbitrary sizes.
For example in HTTP2 we merge or split buffers across fixed-size DATA frame boundaries.

Modifications:
Add new utility class CoalescingBufferQueue

Result:
Following this change HTTP2 code will switch to use it instead of CompositeByteBuffer for DATA frame coalescing.
2015-07-09 07:50:02 -07:00
nmittler
6e044b082c Proper shutdown of HTTP2 encoder when channelInactive
Motivation:

The problem is described in https://github.com/grpc/grpc-java/issues/605. Basically, when using `StreamBufferingEncoder` there is a chance of creating zombie streams that never get closed.

Modifications:

Change `Http2ConnectionHandler`'s `channelInactive` handling logic to shutdown the encoder/decoder before shutting down the active streams.

Result:

Fixes https://github.com/grpc/grpc-java/issues/605
2015-07-09 07:36:42 -07:00
Norman Maurer
8650679f29 Fix regression introduced by 11f9e9084b
Motivation:

While cherry-picked 11f9e9084b I changed the EmbeddedChannel implementation to not allow no ChannelHandlers when constructing it.
This was done by mistake.

Modifications:

Revert change and add unit test.

Result:

Restore old behavior.
2015-07-08 21:37:58 +02:00
Norman Maurer
ab43c78c85 Reduce memory usage by EmbeddedChannel
Motivation:

When using an EmbeddedChannel often it either does inbound or outbound processing which means we only often need one queue.

Modifications:

Lazy init the inbound and outbound message queues.

Result:

Less memory usage.
2015-07-08 10:49:40 +02:00
Norman Maurer
9660e2f6a9 Better handling of BUFFER_OVERFLOW when unwrap data.
Motivation:

When we detect a BUFFER_OVERFLOW we should just forward the already produced data and allocate a new buffer and NOT do any extra memory copies while trying to expand the buffer.

Modifications:

When a BUFFER_OVERFLOW is returned and some data was produced just fire this data through the pipeline and allocate a new buffer to read again.

Result:

Less memorycopies and so better performance.
2015-07-08 09:39:12 +02:00
Norman Maurer
8d1c6ebf71 Only do priming read if there is no space in dsts buffers.
Motivation:

A SSL_read is needed to ensure the bio buffer is flushed, for this we did a priming read. This can be removed in many cases. Also ensure we always fill as much as possible in the destination buffers.

Modifications:

- Only do priming read if capacity of all dsts buffers is zero
- Always produce as must data as possible in the dsts buffers.

Result:

Faster code.
2015-07-08 08:41:18 +02:00
Norman Maurer
18356911ab Stop calling BIO_write once internal buffer is full.
Motivation:

Previous we called BIO_write until either everything was written into it or it returned an error, which meant that the buffer is full. This then needed a ERR_clear_error() call which is expensive.

Modifications:

Break out of writing loop once we detect that not everything was written and so the buffer is full.

Result:

Less overhead when writing more data then the internal buffer can take.
2015-07-08 08:39:21 +02:00
Norman Maurer
a9d2b5cef0 Skip empty buffers and not pass these to BIO_write
Motivation:

When BIO_write is called with an empty buffer it will return 0 for which we call ERR_clear_error(). This is not neccessary as we should just skip these buffers. This eliminates a lot of overhead.

Modifications:

Skip empty src buffers when call unwrap(...).

Result:

Less overhead for unwrap(...) when called with empty buffers.
2015-07-08 08:37:51 +02:00
Norman Maurer
61b9da470a [#3945] Http2ConnectionHandler breaks channelReadComplete pipeline notification
Motivation:

Http2ConnectionHandler missed to forward channelReadComplete(...) events.

Modifications:

Ensure we notify the next handler in the pipeline via ctx.fireChannelReadComplete().

Result:

Correctly forwarding of event.
2015-07-08 08:04:02 +02:00
Scott Mitchell
a7f83aa23e HTTP/2 Example Needs FullHttpRequest
Motivation:
The HTTP/2 hello world example server should be expecting a FullHttpRequest when falling back to HTTP/1.x mode.

Modifications:
- HelloWorldHttp1Handler should process FullHttpRequestObjects
- Http2ServerInitializer should insert an HttpObjectAggregator into the pipeline if no upgrade was attempted

Result:
Responses from the HelloWorldHttp1Handler should only come after full HTTP requests are received.
2015-07-07 13:50:23 -07:00
Scott Mitchell
ecacd11b06 HTTP/2 limit header accumulated size
Motivation:
The Http2FrameListener requires that the Http2FrameReader accumulate ByteBuf objects. There is currently no way to limit the amount of bytes that is accumulated.

Motiviation:
- DefaultHttp2FrameReader supports maxHeaderSize which will fail fast as soon as the maximum size is exceeded.
- DefaultHttp2HeadersDecoder will respect the return value of endHeaderBlock() and fail if the max size is exceeded.

Result:
Frames which carry header data now respect a maximum number of bytes that can be accumulated.
2015-07-07 13:25:03 -07:00
Ryo Okubo
ba84a596e2 Allow servers to specify ENABLE_PUSH to 0 explicitly
Motivation:

If server sends SETTINGS with ENABLE_PUSH, its handled as
PROTOCOL_ERROR in spite of the value. But the value specified to
0 may be allowed in RFC7540.

Modifications:

Check whether ENABLE_PUSH sent from a server is 0 or not.

Result:

When server specifies ENABLE_PUSH to 0 explicitly, client doesn't
handle it as PROTOCOL_ERROR.
2015-07-07 10:00:58 -07:00
Norman Maurer
0f95b85ec2 Ensure OpenSslSession informations can be retrieved even after shutdown
Motivation:

If a user tries to access various informations on the OpenSslSession after the SSLEngine was closed it will not work if these were not accessed before as we lazy init most of them.

Modifications:

Directly populate the whole OpenSslSession once the handshake is complete and before the user is notified about it.

Result:

OpenSslSession informations are avaible until it is GC'ed.
2015-07-07 09:49:52 +02:00
Norman Maurer
0f6559d188 [#3780] Handle ChannelInitializer exception in exceptionCaught()
Motivation:

At the moment we directly closed the Channel when an exception accoured durring initChannel(...) without giving the user any way to do extra or special handling.

Modifications:

Handle the exception in exceptionCaught(...) of the ChannelInitializer which will by default log and close the Channel. This way the user can override this.

Result:

More felixible handling of exceptions.
2015-07-07 09:13:22 +02:00
Norman Maurer
11f9e9084b [#3921] EmbeddedChannel should add ChannelHandlers once registered
Motivation:

Currently in EmbeddedChannel we add the ChannelHandlers before the Channel is registered which leads to have the handlerAdded(...) callback
be called from outside the EventLoop and also prevent the user to obtain a reference to the EventLoop in the callback itself.

Modifications:

Delay adding ChannelHandlers until EmbeddedChannel is registered.

Result:

Correctly call handlerAdded(...) after EmbeddedChannel is registered.
2015-07-07 08:54:27 +02:00
Norman Maurer
dd6ac55fa0 ServerBootstrap.handler(...) will add handler before Channel is registered.
Motivation:

If you set a ChannelHandler via ServerBootstrap.handler(...) it is added to the ChannelPipeline before the Channel is registered. This will lead to and IllegalStateException if a user tries to access the EventLoop in the ChannelHandler.handlerAdded(...) method.

Modifications:

Delay the adding of the ChannelHandler until the Channel was registered.

Result:

No more IllegalStateException.
2015-07-07 08:44:13 +02:00
Norman Maurer
ae163d687d [#3896] Unpooled.copiedBuffer(ByteBuffer) and copiedBuffer(ByteBuffer...) is not thread-safe.
Motivation:

As we modify the position of the passed in ByteBuffer's this methods are not thread-safe.

Modifications:

Duplicate the input ByteBuffers before copy the content to  byte[].

Result:

Unpooled.copiedBuffer(ByteBuffer) and copiedBuffer(ByteBuffer...) is now thread-safe.
2015-07-07 08:38:37 +02:00
Norman Maurer
8c90d602d7 [#3899] Fix javadoc to use netty 4 API.
Motivation:

The javadoc of ByteBuf contained some out-dated code.

Modifications:

Update code example in javadoc to use netty 4+ API

Result:

Correct javadocs
2015-07-03 14:18:53 +02:00
Louis Ryan
ba6319eb6c Fix FixedCompositeByteBuf handling when copying to direct buffers and streams
Motivation:

FixedCompositeByteBuf does not properly implement a number of methods for
copying its content to direct buffers and output streams

Modifications:

Replace improper use of capacity() with readableBytes() when computing offesets during writes

Result:

Copying works correctly
2015-06-27 20:39:31 +02:00
nmittler
b39223e295 Fixing exception in StreamBufferingEncoderTest.
Motivation:

NPE doesn't cause the tests to fail but should get fixed.

Modifications:

Modified the StreamBufferingEncoderTest to mock the ctx to return a promise.

Result:

Fixes #3905
2015-06-24 12:10:09 -07:00
Norman Maurer
c53dbb748e Add ProtocolDetectionResult and use it in HAProxyMessageDecoder for allow detect HAProxy protocol.
Motivation:

Sometimes it is useful to detect if a ByteBuf contains a HAProxy header, for example if you want to write something like the PortUnification example.

Modifications:

- Add ProtocolDetectionResult which can be used as a return type for detecting different protocol.
- Add new method which allows to detect HA Proxy messages.

Result:

Easier to detect protocol.
2015-06-23 08:59:07 +02:00
Norman Maurer
bad8e0d6ab Correctly handle errors when using OpenSSL
Motivation:

We used ERR_get_error() to detect errors and missed to handle different errors. Also we missed to clear the error queue for a thread before invoke SSL operations,
this could lead to detecting errors on different OpenSslEngines then the one in which the error actual happened.

Modifications:

Explicit handle errors via SSL.get_error and clear the error code before SSL operations.

Result:

Correctly handle errors and no false-positives in different OpenSslEngines then the one which detected an error.
2015-06-21 21:06:42 +02:00
nmittler
391df0547b Fixing broken build in the 4.1 branch. 2015-06-19 16:08:37 -07:00
Louis Ryan
05ce33f5ca Make the flow-controllers write fewer, fatter frames to improve throughput.
Motivation:

Coalescing many small writes into a larger DATA frame reduces framing overheads on the wire and reduces the number of calls to Http2FrameListeners on the remote side.
Delaying the write of WINDOW_UPDATE until flush allows for more consumed bytes to be returned as the aggregate of consumed bytes is returned and not the amount consumed when the threshold was crossed.

Modifications:
- Remote flow controller no longer immediately writes bytes when a flow-controlled payload is enqueued. Sequential data payloads are now merged into a single CompositeByteBuf which are written when 'writePendingBytes' is called.
- Listener added to remote flow-controller which observes written bytes per stream.
- Local flow-controller no longer immediately writes WINDOW_UPDATE when the ratio threshold is crossed. Now an explicit call to 'writeWindowUpdates' triggers the WINDOW_UPDATE for all streams who's ratio is exceeded at that time. This results in
  fewer window updates being sent and more bytes being returned.
- Http2ConnectionHandler.flush triggers 'writeWindowUpdates' on the local flow-controller followed by 'writePendingBytes' on the remote flow-controller so WINDOW_UPDATES preceed DATA frames on the wire.

Result:
- Better throughput for writing many small DATA chunks followed by a flush, saving 9-bytes per coalesced frame.
- Fewer WINDOW_UPDATES being written and more flow-control bytes returned to remote side more quickly, thereby improving throughput.
2015-06-19 15:20:31 -07:00
nmittler
1ecc37fbb2 Better error when first HTTP/2 frame is not SETTINGS
Motivation:

Bootstrap of the HTTP/2 can take a lot of paths and a lot of things can go wrong in the initial handshakes leading up to establishment of HTTP/2 between client and server. There have been many times where handshakes have failed silently, leading to very cryptic errors that are hard to debug.

Modifications:

Changed the HTTP/2 handler and decoder to ensure that the very first data on the wire (WRT HTTP/2) is SETTINGS/preface+SETTINGS. When this is not the case, a connection error is thrown with the bytes that were found instead.

Result:

Fixes #3880
2015-06-18 15:58:42 -07:00
a-mkarjalainen
e1e8a59ad9 Fix broken constructor chaining for FixedChannelPool class.
Motivation:

Only one of the three FixedChannelPool constructors checks for the constructor
arguments. Therfore it was possible to create a pool with zero maxConnections.

This change chains all constructors together, so that the last one
in the chain always checks the validity of the arguments, regardless of the
constructor used.

Result:

It is no longer possible to create a FixedChannelPool instance with invalid
maxConnections or maxPendingAcquires parameters.
2015-06-18 20:11:04 +02:00
Norman Maurer
e0ef01cf93 [#3888] Use 2 * cores as default minimum for pool arenas.
Motivation:

At the moment we use 1 * cores as default mimimum for pool arenas. This can easily lead to conditions as we use 2 * cores as default for EventLoop's when using NIO or EPOLL. If we choose a smaller number we will run into hotspots as allocation and deallocation needs to be synchronized on the PoolArena.

Modifications:

Change the default number of arenas to 2 * cores.

Result:

Less conditions when using the default settings.
2015-06-18 07:27:30 +02:00
Norman Maurer
29ac2ae3c2 [#3883] OpenSSL SSLSession returns incorrect peer principal
Motivation:

According to the javadocs of SSLSession.getPeerPrincipal should be returning the identity of the peer, while we return the identity of the issuer.

Modifications:

Return the correct indentity.

Result:

Behavior match the documentation.
2015-06-17 06:36:13 +02:00
Norman Maurer
4a0d68c50b [#3881] FixedChannelPool creates 1 more channel than maxConnections
Motivation:

FixedChannelPool should enforce a number of maximal used channels, but due a bug we fail to correctly enforce this.

Modifications:

Change check to correctly only acquire channel if we not hit the limit yet.

Result:

Correct limiting.
2015-06-16 20:10:27 +02:00
Scott Mitchell
09d826ed46 Channel writable bytes feature
Motivation:
To avoid buffering too much it would be useful to get an estimate of how many bytes can be written to a Channel before it becomes unwritable.

Modifications:
- Update the Channel interface to support 2 new methods. 1 to give how many bytes before unwritable. 1 to give how many bytes before writable.
- Update the AbstractChannel implementation to delegate to the ChannelOutboundBuffer.

Result:
The Channel interface supports 2 new methods which provide more visibility into writability.
2015-06-12 12:39:53 -07:00
Frederic Bregier
caa1505020 Get uploaded size while upload is in progress
Proposal to fix issue #3636

Motivations:
Currently, while adding the next buffers to the decoder
(`decoder.offer()`), there is no way to access to the current HTTP
object being decoded since it can only be available currently once fully
decoded by `decoder.hasNext()`.
Some could want to know the progression on the overall transfer but also
per HTTP object.
While overall progression could be done using (if available) the global
Content-Length of the request and taking into account each HttpContent
size, the per HttpData object progression is unknown.

Modifications:
1) For HTTP object, `AbstractHttpData` has 2 protected properties named
`definedSize` and `size`, respectively the supposely final size and the
current (decoded until now) size.
This provides a new method `definedSize()` to get the current value for
`definedSize`. The `size` attribute is reachable by the `length()`
method.

Note however there are 2 different ways that currently managed the
`definedSize`:
a) `Attribute`: it is reset each time the value is less than actual
(when a buffer is added, the value is increased) since the final length
is not known (no Content-Length)
b) `FileUpload`: it is set at startup from the lengh provided

So these differences could lead in wrong perception;
a) `Attribute`: definedSize = size always
b) `FileUpload`: definedSize >= size always

Therefore the comment tries to explain clearly the different behaviors.

2) In the InterfaceHttpPostRequestDecoder (and the derived classes), I
add a new method: `decoder.currentPartialHttpData()` which will return a
`InterfaceHttpData` (if any) as the current `Attribute` or `FileUpload`
(the 2 generic types), which will allow then the programmer to check
according to the real type (instance of) the 2 methods `definedSize()`
and `length()`.

This method check if currentFileUpload or currentAttribute are null and
returns the one (only one could be not null) that is not null.

Note that if this method returns null, it might mean 2 situations:
a) the last `HttpData` (whatever attribute or file upload) is already
finished and therefore accessible through `next()`
b) there is not yet any `HttpData` in decoding (body not yet parsed for
instance)

Result:
The developper has more access and therefore control on the current
upload.
The coding from developper side could looks like in the example in
HttpUloadServerHandler.
2015-06-12 14:16:07 +02:00
Norman Maurer
3a4d64bb84 Allow to receive a ChannelGroupFuture that will be notified once all Channels are closed.
Motivation:

It's useful to be able to be notified once all Channels that are part of the ChannelGroup are notified. This can for example be useful if you want to do a graceful shutdown.

Modifications:

- Add ChannelGroup.newCloseFuture(...) which will be notified once all Channels are notified that are part of the ChannelGroup at the time of calling.

Result:

Easier to be notified once all Channels within a ChannelGroup are closed.
2015-06-12 13:56:33 +02:00
Scott Mitchell
43a558b9e1 ChannelOutboundBuffer bytes before writable accessor
Motiviation:
There are currently no accessors which provide visbility into how many bytes must be written in order for a writability change to occur. This feature would be useful for codecs which intent to control how many bytes are queued at any given time.

Modifications:
- add bytesBeforeUnWritable() which will give the number of bytes before the buffer (and associated channel) transitions to not writable
- add bytesBeforeWritable() which will give the number of bytes that must be drained from the queue until the channel becomes writable.

Result:
More visibility into writability for the ChannelOutboundBuffer.
2015-06-10 08:44:03 -07:00
Norman Maurer
d1b7f990f2 Not skip first cert when using OpenSslClientContext
Motivation:

Due a copy and paste error we incorrectly skipped the first cert in the keyCertChainFile when using OpenSslClientContext.

Modifications:

Correctly not skip the first cert.

Result:

The certificate chain is correctly setup when using OpenSslClientContext.
2015-06-10 09:01:31 +02:00
Trustin Lee
b169a76d46 Fix the failing HttpObjectAggregatorTest.testInvalidConstructorUsage()
Related: 950da2eae1
2015-06-10 12:20:50 +09:00
Trustin Lee
0ca65f1373 Lazily instantiate HttpServerUpgradeHandler.UpgradeCodec
Related: #3814

Motivation:

To implement the support for an upgrade from cleartext HTTP/1.1
connection to cleartext HTTP/2 (h2c) connection, a user usually uses
HttpServerUpgradeHandler.

It does its job, but it requires a user to instantiate the UpgradeCodecs
for all supported protocols upfront. It means redundancy for the
connections that are not upgraded.

Modifications:

- Change the constructor of HttpServerUpgradeHandler
  - Accept UpgraceCodecFactory instead of UpgradeCodecs
- The default constructor of HttpServerUpgradeHandler sets the
  maxContentLength to 0 now, which shouldn't be a problem because a
  usual upgrade request is a GET.
- Update the examples accordingly

Result:

A user can instantiate Http2ServerUpgradeCodec and its related objects
(Http2Connection, Http2FrameReader/Writer, Http2FrameListener, etc) only
when necessary.
2015-06-10 12:06:27 +09:00
Trustin Lee
950da2eae1 Allow MessageAggregator to disallow non-empty content
Motivation:

A user sometimes just want the aggregated message has no content at
all. (e.g. A user only wants HTTP GET requests.)

Modifications:

- Do not raise IllegalArgumentException even if a user specified
  the maxContentLength of 0

Result:

A user can disallow a message with non-empty content.
2015-06-10 12:06:27 +09:00
Trustin Lee
73d79a4b3b Do not use hard-coded handler names in HTTP/2
Motivation:

Our HTTP/2 implementation sometimes uses hard-coded handler names when
adding/removing a handler to/from a pipeline. It's not really a good
idea because it can easily result in name clashes. Unless there is a
good reason, we need to use the reference to the handlers

Modifications:

- Allow null as a handler name for Http2Client/ServerUpgradeCodec
  - Use null as the default upgrade handler name
- Do not use handler name strings in some test cases and examples

Result:

Fixes #3815
2015-06-10 11:46:02 +09:00
Trustin Lee
e72d04509f Fix a buffer leak in StreamBufferingEncoderTest
Related: #3871

Motivation:

StreamBufferingEncoderTest does not release when writeGoAway() is
called.

Modifications:

Release the buffer in mock object arguments

Result:

No buffer leak
2015-06-09 14:27:02 +09:00
Norman Maurer
4570f30dd9 [#3798] Extract dump method to ByteBufUtil
Motivation:

Dumping the content of a ByteBuf in a hex format is very useful.

Modifications:

Move code into ByteBufUtil so its easy to reuse.

Result:

Easy to reuse dumping code.
2015-06-09 06:21:09 +02:00
Scott Mitchell
5c22a01522 HTTP/2 shutdown cleanup miss
Motiviation:
https://github.com/netty/netty/pull/3865 was merged from a machine with old code. A test case that was updates was not merged.

Modifications:
- Merge the missing test case updates

Result:
Test case no longer fails.
2015-06-08 07:59:36 -07:00
Scott Mitchell
49b0d6ed07 HTTP/2 ConnectionHandler close cleanup
Motiviation:
The connection handler stream close operation is unconditionally adding a listener object to a future. We may not have to add a listener at all because the future has already been completed.

Modifications:
- If the future is done, directly invoke the logic without creating/adding a new listener.

Result:
No need to create/add listener if the future is already done in close logic.
2015-06-08 07:47:15 -07:00
Norman Maurer
e9a2cac16d [#3869] Add unit test to ensure adding null header values is not allowed.
Motivation:

We need to ensure we never allow to have null values set on headers, otherwise we will see a NPE during encoding them.

Modifications:

Add unit test that shows we correctly handle null values.

Result:

Verify correct implementation.
2015-06-08 09:59:44 +02:00
Norman Maurer
cf54c04241 Correctly respect readerIndex of buffer when dumping.
Motivation:

The current dumping code does not respect the readerIndex and so logs incorrect.

Modifications:

Respect readerIndex of ByteBuf

Result:

Correctly log content of buffer.
2015-06-08 09:23:40 +02:00
Norman Maurer
a485ae68dc Guard against race when calling SslHandler.handshakeFuture().sync()
Motivation:

If the handlerAdded(...) callback was not called, the checkDeadLock() of the handshakeFuture will produce an IllegalStateException.
This was first reported at https://github.com/impossibl/pgjdbc-ng/issues/168 .

Modifications:

Pass deadlock check if ctx is null

Result:

No more race and so IllegalStateException.
2015-06-08 09:17:27 +02:00
Norman Maurer
6f9eb2cd34 Update javadocs to highlight that derived buffers will not increment the reference count.
Motivation:

We not explain the derived buffers will not retain the parent buffer.

Modifications:

Add docs.

Result:

Correctly document behaviour
2015-06-06 19:54:38 +02:00
Norman Maurer
49643fb5b1 [#3848] Respect EPOLLERR event
Motivation:

Some glibc/kernel versions will trigger an EPOLLERR event to notify
about failed connect and not an EPOLLOUT. Also EPOLLERR may be triggered
when a connection is broke.

Modification:

React on EPOLLERR like if an EPOLLOUT / EPOLLIN was received, this will work in
all cases as we handle errors in EPOLLOUT / EPOLLIN anyway.

Result:

Correctly detect errors.
2015-06-06 10:34:58 +02:00
nmittler
d2615ab532 Porting BufferingHttp2ConnectionEncoder from gRPC
Motivation:

gRPC's BufferingHttp2ConnectionEncoder is a generic utility that simplifies client-side applications that want to allow stream creation without worrying about violating the SETTINGS_MAX_CONCURRENT_STREAMS limit.  Since it's not gRPC-specific it makes sense to move it into Netty proper.

Modifications:

Adding the BufferingHttp2ConnectionEncoder and it's unit test.

Result:

Netty now supports buffering stream creation.
2015-06-05 05:51:16 -07:00