fillInterested() is called.
This is needed to avoid race conditions where fillInterested()
triggers a new thread entering onFillable() and acquiring a new buffer
while the previous thread is releasing the previous buffer.
Now instead of having the channel to dispatch when it detects that it
has to call the application (upon receiving a HEADERS frame, or upon
a push "fake" request), now the whole mechanism is controlled by an
ExecutionStrategy.
Introduced parameter "dispatchIO" in the relevant factories so that
they can be configured by users and connections will be created
taking into account this parameter.
For less configurable connection factories, this parameter is
currently hardcoded to either true or false depending on the case.
For example, ALPN and NPN connections have it to false, since they
don't do any blocking operation in onFillable().
Introduced ResetException, and using it when failing frames of streams
that have been reset already.
HttpTransportOverHTTP2.abort(Throwable) checks for this exception and
does not close the connection.
A PushCacheFilter contains the logic to associate secondary resources
to primary resources.
PushCacheFilter calls a Jetty-specific API on the request dispatcher:
Dispatcher.push(ServletRequest). This is a technology preview of the
push functionality slated for Servlet 4.0.
The push() invocation arrives to the transport and it is converted to
HTTP/2 specific PUSH_PROMISE, along with the mechanism to simulate
the request for the secondary resource.
It's now sent after a call to onPreface(), which has been moved to
the common interface Session.Listener (from ServerSession.Listener),
so that client applications can customize the SETTINGS to send to the
server.
Flow control window updates are now processed by the flusher, so that
it is the only component that handles window updates.
In the process of this refactoring, HTTP2Flusher was refactored out
of HTTP2Session.
There is a difference between the value set via configuration, that
always refer to remote streams (streams initiated by remote peers),
and the value received via SETTINGS frame, that always refer to local
streams (streams initiated locally).
The case was that shutdown was called, ShutdownFlusherEntry called
flusher.close(), which called super.close(), which called
onCompleteFailure(), which looped over the active items to fail them,
calling again ShutdownFlusherEntry, which called again flusher.close(),
etc.