You could previously do this with evbuffer_peek() and some memcpys,
but it was a bit more work than most folks wanted to get into.
Closes sourceforge ticket 3108072
The sendfile() implementation for evbuffer_add_file is potentially more
efficient, but it has a problem: you can only use it to send bytes over
a socket using sendfile(). If you are writing bytes via SSL_send() or
via a filter, or if you need to be able to inspect your buffer, it
doesn't work.
As an easy fix, this patch disables the sendfile-based implementation of
evbuffer_add_file on an evbuffer unless the user sets a new
EVBUFFER_FLAG_DRAINS_TO_FD flag on that evbuffer, indicating that the
evbuffer will not be inspected, but only written out via
evbuffer_write(), evbuffer_write_atmost(), or drained with stuff like
evbuffer_drain() or evbuffer_add_buffer(). This flag is off by
default, except for evbuffers used for output on bufferevent_socket.
In the future, it could be interesting to make a best-effort file
segment implementation that tries to send via sendfile, but mmaps on
demand. That's too much complexity for a stable release series, though.
This change has no effect on non-windows platforms, since those
either define off_t to 64-bits, or allow you to decide whether
it should be 64-bits yourself via some LARGEFILE-like macro.
On Windows, however, off_t is always 32-bit, so it's a bad choice
for "file size" or "file offset" values. Instead, I'm adding
an ev_off_t type, and using it in the one place where we used
off_t to mean "the size of a file" or "an offset into a file" in the
API.
This breaks ABI compatibility on Windows.
The evbuffer_remove() function copies data from the front of an
evbuffer into an array of char, and removes the data from the buffer.
This function behaves the same, but does not remove the data. This
behavior can be handy for lots of protocols, where you want the
evbuffer to accumulate data until a complete record has arrived.
Lots of people have asked for a function more or less like this, and
though it isn't too hard to code one from evbuffer_peek(), it is
apparently annoying to do it in every app you write. The
evbuffer_peek() function is significantly faster, but it requires that
the user be able to handle data in separate extents.
This patch also reimplements evbufer_remove() as evbuffer_copyout()
followed by evbuffer_drain(). I am reasonably confident that this
won't be a performance hit: the memcpy() overhead should dominate the
cost of walking the list an extra time.
This can be handy when you have one search to find the end of a header
section, and then you want to find a substring within the header
section without looking at the body.
svn:r1410
Previously, set_flags() would replace all previous user-visible flags.
Now it just sets the flags, and there is a clear_flags() function to
clear other flags.
svn:r1293
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
The old evbuffer_find didn't allow iterative searching, and forced us
to repack the buffer completely every time we searched in it. The
new evbuffer_search addresses both of these. As a side-effect, the
evbuffer_find implementation is now a little more efficient.
svn:r1130
a) this is 2009
b) niels and nick have been comaintainers for a while
c) saying "all rights reserved" when you then go on to explicitly
disclaim some rights is sheer cargo-cultism.
svn:r1065
For now, there is just one: enabled. This lets us avoid lots of
mallocs/frees/tailq-manipulations just to turn a callback on and off.
The revised bufferevent code wants this.
svn:r1047
