Previously, if BEV_OPT_CLOSE_ON_FREE wasn't set on a
bufferevent_filter or a filtering bufferevent_openssl, when we went
to free the filtering bufferevent, we'd leave the underlying
bufferevent unchanged. That's not so good, since the callbacks are
set to activate stuff in the filtering bufferevent that we're about
to free. Instead, set all the callbacks to NULL.
Previously, whenever writing was disabled on a bufferevent_filter (or
a filtering SSL bufferevent), we would stop writing on the underlying
bufferevent. This would make for trouble, though, since if you
implemented common patterns like "stop writing once data X has been
flushed", your bufferevent filter would disable the underlying
bufferevent after the data was flushed to the underlying bufferevent,
but before actually having it written to the network.
Now, we have filters leave their underlying bufferevents enabled for
reading and writing for reading and writing immediately. They are not
disabled, unless the user wants to disable them, which is now allowed.
To handle the case where we want to choke reading on the underlying
bufferevent because the filter no longer wants to read, we use
bufferevent_suspend_read(). This is analogous to the way that we use
bufferevent_suspend_write() to suspend writing on a filtering
bufferevent when the underlying bufferevent's output buffer has hit
its high watermark.
The different bufferevent implementations had different behavior for
their timeouts. Some of them kept re-triggering the timeouts
indefinitely; some disabled the event immediately the first time a
timeout triggered. Some of them made the timeouts only count when
the bufferevent was actively trying to read or write; some did not.
The new behavior is modeled after old socket bufferevents, since
they were here first and their behavior is relatively sane.
Basically, each timeout disables the bufferevent's corresponding
read or write operation when it fires. Timeouts are stopped
whenever we suspend writing or reading, and reset whenever we
unsuspend writing or reading. Calling bufferevent_enable resets a
timeout, as does changing the timeout value.
In many places throughout the code, we called _bufferevent_run_eventcb
without checking whether the eventcb was actually set. This would
work fine when the bufferevent's callbacks were deferred, but
otherwise the code would segfault. Strangely, we always remembered to
check before calling the _bufferevent_run_{read,write}cb functions.
To prevent similar errors in the future, all of
_buferevent_run_{read,write,event}cb now check to make sure the
callback is actually set before invoking or deferring the callback.
This patch also removes the now-redundant checks for {read,write}cb.
This makes our interfaces usable from C++, which doesn't believe
you can say "bufferevent_socket_nase(base, -1,
BEV_OPT_CLOSE_ON_FREE|BEV_OPT_DEFER_CALLBACKS)" but which instead
would demand "static_cast<bufferevent_options>(BEV_OPT_CLOSE_ON_FREE|
BEV_OPT_DEFER_CALLBACKS))" for the last argument.
Diagnosis and patch from Chris Davis.
svn:r1456
This code adds a new Bufferevent type that is only compiled when the
openssl library is present. It supports using an SSL object and an
event alert mechanism, which can either be an fd or an underlying
bufferevent.
There is still more work to do: the unit tests are incomplete, and we
need to support flush and shutdown much better. Sometimes events are
generated needlessly: this will hose performance.
There's a new encrypting proxy in sample/le-proxy.c.
This code has only been tested on OSX, and nowhere else.
svn:r1382
Rationale: we hold a lock on the bufferevent when its callbacks are
executing, so we need to release the lock afterwards. But the
callback might free the bufferevent, so unless we're holding a
reference on the bufferevent, the lock might not be there for us to
release.
svn:r1347
Paired and asynchronous bufferevents didn't do timeouts, and filtering
bufferevents gave them funny semantics. Now they all should all work
in a way consistent with what socket bufferevents do now: a [read/write]
timeout triggers if [reading/writing] is enabled, and if the timeout is
set, and the right amount of time passes without any data getting
[added to the input buffer/drained from the output buffer].
svn:r1314
OpenSSL uses something like this to implement get/set access for
properties on its BIOs, so that it doesn't need to add a pair of
get/set functions to the vtable struct for every new abstract property
it provides an accessor for.
Doing this lets us make bufferevent_setfd abstract, and implement an
abstract bufferevent_getfd.
svn:r1284
This way we don't expose more of a bufferevent than we need to. One
motivation is to make it easier to automatically get deferred callbacks
with a bufferevent without exposing the deferred_cb structure.
svn:r1169
The new bufferevent_pair abstraction works like a set of buferevent_sockets
connected by a socketpair, except that it doesn't require a socketpair,
and therefore doesn't need to get the kernel involved.
It's also a good way to make sure that deferred callbacks work. It's a good
use case for deferred callbacks: before I implemented them, the recursive
relationship between the evbuffer callback and the read callback would
make the unit tests overflow the stack.
svn:r1152
