xcffib
is intended to be a (mostly) drop-in replacement for xpyb
. xpyb
has an inactive upstream, several memory leaks, is python2 only and doesn't
have pypy support. xcffib
is a binding which uses
cffi, which mitigates some of the issues
described above. xcffib
also builds bindings for 27 of the 29 (xprint and xkb
are missing) X extensions in 1.10.
Installation
For most end users of software that depends on xcffib or developers writing
code against xcffib, you can use the version of xcffib on pypi. To install it,
you'll need libxcb's headers and libxcb-render's headers (these are available
via sudo apt-get install libxcb-render0-dev
on Ubuntu). Once you have the C
headers installed, you can just pip install xcffib
.
If you're interested in doing development, read on...
Development dependencies
You should be able to install all the language deps from hackage or pip. The .travis.yaml has an example of how to install the dependencies on Ubuntu flavors.
Hacking
See the Makefile for
examples on how to run the tests. Your contribution should at pass make check
before it can be merged. The newtests
make target can be used to regenerate
expected haskell test data if the tests are failing because you made a change
to the generated python code.
Hacking on new xcb-proto versions
Sometimes (more often recently), xcb-proto makes some updates that we need to
do some work for. These often require some updates to xcb-types
as well.
First, hack your changes into xcb-types
and cabal install
them., then git
clone the version of xcb-proto you want to somewhere, e.g. ~/packages
:
~/packages $ git clone http://anongit.freedesktop.org/git/xcb/proto.git xcb-proto`
Finally, you can build/test xcffib against this custom version of
xcb-{proto|types}
with:
make XCBDIR=~/packages/xcb-proto/src check
Differences
In general, you should s/xcb/xcffib/g
. Explicit differences are listed below,
however I don't think these will prevent any porting, because these were either
not public APIs, or not actually generated (in the case of the exceptions) by
xpyb
. I think most porting should Just Work via the regex above.
xcb.Exception
is spelledxcffib.XcffibException
and is also a parent of all exceptions generated by xcffib.xcb.ConnectException
is gone, it was unusedxcffib.ConnectionException
is raised on connection errorsxcb.Iterator
is gone; similar functionality is implemented byxcffib.pack_list
.xcb.Request
is gone. It was an entirely internal and unnecessary interface.xcffib.Connection.send_request
takes slightly different (but more sensible) arguments.- Everywhere
xcb-proto
sayschar
,xcffib
uses a char. That means on input for a<list type="char"/>
, you can use a python string literal.xcffib
also gives you a string of length 1 out for each element in such a list, instead of anint
. Finally, there is a helper method calledto_string
onxcffib.List
, to convert these string-like things into native strings. In both python2 and python3 you get a nativestr
. This means that for things likexproto.STR
, you can just dothe_str.name.to_string()
instead of''.join(map(chr, the_str.name))
. - As above,
void
is also packed/unpacked aschar
s, since the convention is to use it as string data, e.g. inxproto.ChangeProperty
. - The submodule
xcb
is gone. The top module re-exported all these constants anyway, so they live there now. i.e.xcb.xcb.CurrentTime
is now justxcffib.CurrentTime
.
Enhancements
-
When sending requests with nested structs you no longer have to pack the contents yourself. For example, when calling
xproto.FillPoly
, you used to have to convert thePOINT
s you were passing in to some sort of buffer which had themstruct.pack
'd. Now, you can just pass an iterable (orxcffib.List
) ofPOINT
s and it will be automatically packed for you. -
Most of the lower level XCB connection primitives that were previously not exposed are now available via
xcffib.{ffi,C}
, assuming you want to go out of band of the binding. -
Checked vs. Unchecked requests are still supported (via Checked and Unchecked function calls). However, there is also an additional optional parameter
is_checked
to each request function, to allow you to set the checked status that way. Additionally, requests that are (un)checked by default, e.g.QueryTree
(CreateWindow
), have aQueryTreeChecked
(CreateWindowUnchecked
) version which just has the same default behavior. -
The
FooError
BadFoo
duality is gone; it was difficult to understand what to actually catch if you wanted to handle an error. Instead,FooError
andBadFoo
are aliases, and both implement the X error object description and python Exception (via inheriting fromXcffibException
). -
You can now create synthtic events. This makes it much easier to work with
ClientMessageEvent
s. For example:e = xcffib.xproto.ClientMessageEvent.synthetic(format=..., window=..., ...) conn.core.SendEvent(..., e.pack())
Why haskell?
Why is the binding generator written in haskell? Because haskell is awesome.
TODO
- XGE support? (xpyb doesn't implement this either)
- xprint and xkb support. These will require some non-trivial work in xcb-types, since it won't parse them correctly.