rust-cpython: implement Graph using C parents function
We introduce the `Index` struct that wraps the C index. It is
not intrinsically protected by the GIL (see the lengthy
discussion in its docstring). Improving on this seems
prematurate at this point.
A pointer to the parents function is stored on the parsers
C extension module as a capsule object.
This is the recommended way to export a C API for consumption
from other extensions.
See also: https://docs.python.org/2.7/c-api/capsule.html
In our case, we use it in cindex.rs, retrieving function
pointer from the capsule and storing it within the CIndex
struct, alongside with a pointer to the index. From there,
the implementation is very close to the one from hg-direct-ffi.
The naming convention for the capsule is inspired from the
one in datetime:
>>> import datetime
>>> datetime.datetime_CAPI
<capsule object "datetime.datetime_CAPI" at 0x7fb51201ecf0>
although in datetime's case, the capsule points to a struct holding
several type objects and methods.
Differential Revision: https://phab.mercurial-scm.org/D5438
syntax: glob
*.elc
*.tmp
*.orig
*.rej
*~
*.mergebackup
*.o
*.so
*.dll
*.exe
*.pyd
*.pyc
*.pyo
*$py.class
*.swp
*.prof
*.zip
\#*\#
.\#*
tests/artifacts/cache/big-file-churn.hg
tests/.coverage*
tests/.testtimes*
tests/.hypothesis
tests/hypothesis-generated
tests/annotated
tests/exceptions
tests/*.err
tests/htmlcov
build
contrib/chg/chg
contrib/hgsh/hgsh
contrib/vagrant/.vagrant
dist
packages
doc/common.txt
doc/*.[0-9]
doc/*.[0-9].txt
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
MANIFEST.in
patches
mercurial/__modulepolicy__.py
mercurial/__version__.py
mercurial/hgpythonlib.h
mercurial.egg-info
.DS_Store
tags
cscope.*
.idea/*
.asv/*
i18n/hg.pot
locale/*/LC_MESSAGES/hg.mo
hgext/__index__.py
rust/target/
rust/*/target/
# Generated wheels
wheelhouse/
syntax: regexp
^\.pc/
^\.(pydev)?project
# hackable windows distribution additions
^hg-python
^hg.py$