docs: Add automatic cross-reference for C types

In order to cross-reference C types in the documentation, Sphinx
requires the syntax :c:type:`type_name`, or even :c:type:`struct
type_name <type_name>` in order to have the link text different from the
target text.

Extend automarkup to enable automatic cross-reference of C types by
matching any "struct|union|enum|typedef type_name" expression.
This makes the documentation's plain text cleaner and adds
cross-reference to types without any additional effort by the author.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@protonmail.com>
Link: https://lore.kernel.org/r/20200903005747.3900333-2-nfraprado@protonmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Nícolas F. R. A. Prado 2020-09-03 00:58:19 +00:00 committed by Jonathan Corbet
parent f67281a72b
commit d82b1e833e

View File

@ -13,6 +13,7 @@ if sphinx.version_info[0] < 2 or \
else:
from sphinx.errors import NoUri
import re
from itertools import chain
#
# Regex nastiness. Of course.
@ -21,7 +22,8 @@ import re
# :c:func: block (i.e. ":c:func:`mmap()`s" flakes out), so the last
# bit tries to restrict matches to things that won't create trouble.
#
RE_function = re.compile(r'([\w_][\w\d_]+\(\))')
RE_function = re.compile(r'(([\w_][\w\d_]+)\(\))')
RE_type = re.compile(r'(struct|union|enum|typedef)\s+([\w_][\w\d_]+)')
#
# Many places in the docs refer to common system calls. It is
@ -35,31 +37,39 @@ Skipfuncs = [ 'open', 'close', 'read', 'write', 'fcntl', 'mmap',
'socket' ]
#
# Find all occurrences of function() and try to replace them with
# appropriate cross references.
# Find all occurrences of C references (function() and struct/union/enum/typedef
# type_name) and try to replace them with appropriate cross references.
#
def markup_funcs(docname, app, node):
def markup_c_refs(docname, app, node):
class_str = {RE_function: 'c-func', RE_type: 'c-type'}
reftype_str = {RE_function: 'function', RE_type: 'type'}
cdom = app.env.domains['c']
t = node.astext()
done = 0
repl = [ ]
for m in RE_function.finditer(t):
#
# Sort all C references by the starting position in text
#
sorted_matches = sorted(chain(RE_type.finditer(t), RE_function.finditer(t)),
key=lambda m: m.start())
for m in sorted_matches:
#
# Include any text prior to function() as a normal text node.
# Include any text prior to match as a normal text node.
#
if m.start() > done:
repl.append(nodes.Text(t[done:m.start()]))
#
# Go through the dance of getting an xref out of the C domain
#
target = m.group(1)[:-2]
target_text = nodes.Text(target + '()')
target = m.group(2)
target_text = nodes.Text(m.group(0))
xref = None
if target not in Skipfuncs:
lit_text = nodes.literal(classes=['xref', 'c', 'c-func'])
if not (m.re == RE_function and target in Skipfuncs):
lit_text = nodes.literal(classes=['xref', 'c', class_str[m.re]])
lit_text += target_text
pxref = addnodes.pending_xref('', refdomain = 'c',
reftype = 'function',
reftype = reftype_str[m.re],
reftarget = target, modname = None,
classname = None)
#
@ -68,7 +78,8 @@ def markup_funcs(docname, app, node):
#
try:
xref = cdom.resolve_xref(app.env, docname, app.builder,
'function', target, pxref, lit_text)
reftype_str[m.re], target, pxref,
lit_text)
except NoUri:
xref = None
#
@ -97,7 +108,7 @@ def auto_markup(app, doctree, name):
for para in doctree.traverse(nodes.paragraph):
for node in para.traverse(nodes.Text):
if not isinstance(node.parent, nodes.literal):
node.parent.replace(node, markup_funcs(name, app, node))
node.parent.replace(node, markup_c_refs(name, app, node))
def setup(app):
app.connect('doctree-resolved', auto_markup)