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
A 'deferred callback' is just a function that we've queued in the
event base. This ability is needed for some mt stuff, and for complex
callback chains. For internal use only.
svn:r1150
This is exceptionally important with multithreaded stuff, where we use
an event to notify the base that other events have been made active.
If the activated events have a prioirty number greater than that of the
notification event, it will starve them, and that's no good.
svn:r1149
In particular, we don't allow adding any data to end front of inbuf
(we do that when we read), or removing it from the front of outbuf (we
drain data only when we write).
svn:r1144
From the documentation:
Prevent calls that modify an evbuffer from succeeding. A buffer may
frozen at the front, at the back, or at both the front and the back.
If the front of a buffer is frozen, operations that drain data from
the front of the buffer, or that prepend data to the buffer, will
fail until it is unfrozen. If the back a buffer is frozen, operations
that append data from the buffer will fail until it is unfrozen.
We'll use this to ensure correctness on an evbuffer when we're waiting
for an overlapped IO call to finish.
svn:r1143
For overlapped IO (and possibly other stuff) we need to be able to
label an evbuffer_chain as "pinned", meaning that every byte in it
must remain at the same address as it is now until it unpinned. This
differs from being "immutable": it is okay to add data to the end
of a pinned chain, so long as existing data is not moved.
svn:r1142
The bug could occur when a nameserver was marked as up, but then an
outstanding probe sent to the nameserver failed. Now, evdns_up() cancels
any outstanding probe.
svn:r1140
