This commit is related to #27260. Currently there is a weird
relationship between channel contexts and nio channels. The selectors
use the context for read and writing. But the selector operates directly
on the nio channel for registering, closing, and connecting.
This commit works on improving this relationship. The selector operates
directly on the context which wraps the low level java.nio.channels. The
NioChannel class is simply an API that is used to interact with the
channel (sending messages from outside the selector event loop,
scheduling a close, adding listeners, etc). The context is only used
internally by the channel to implement these apis and by the selector to
perform these operations.
This commit is related to #27260. Currently have a channel context that
implements reading and writing logic for socket channels. Additionally,
we have exception contexts to handle exceptions. And accepting contexts
to handle accepted channels. This PR introduces a ChannelContext that
handles close and exception handling for all channel types.
Additionally, it has implementers that provide specific functionality
for socket channels (read and writing). And specific functionality for
server channels (accepting).
This commit is related to #27260. Right now we have separate read and
write contexts for implementing specific protocol logic. However, some
protocols require a closer relationship between read and write
operations than is allowed by our current model. An example is HTTP
which might require a write if some problem with request parsing was
encountered.
Additionally, some protocols require close messages to be sent when a
channel is shutdown. This is also problematic in our current model,
where we assume that channels should simply be queued for close and
forgotten.
This commit transitions to a single ChannelContext which implements
all read, write, and close logic for protocols. It is the job of the
context to tell the selector when to close the channel. A channel can
still be manually queued for close with a selector. This is how server
channels are closed for now. And this route allows timeout mechanisms on
normal channel closes to be implemented.
The method `initiateChannel` on `TcpTransport` is explicit in that
channels can be connect asynchronously. All production implementations
do connect asynchronously. Only the blocking `MockTcpTransport`
connects in a synchronous manner. This avoids testing some of the
blocking code in `TcpTransport` that waits on connections to complete.
Additionally, it requires a more extensive method signature than
required for other transports.
This commit modifies the `MockTcpTransport` to make these connections
asynchronously on a different thread. Additionally, it simplifies that
`initiateChannel` method signature.
This commit is related to #27260. It moves the TcpChannelFactory into
NioTransport so that consumers do not have to be passed around.
Additionally it deletes an unused read handler.
This is related to #27260. This commit moves the NioTransport from
:test:framework to a new nio-transport plugin. Additionally, supporting
tcp decoding classes are moved to this plugin. Generic byte reading and
writing contexts are moved to the nio library.
Additionally, this commit adds a basic MockNioTransport to
:test:framework that is a TcpTransport implementation for testing that
is driven by nio.
Tim Brooks
Igor Motov