# SPDX-License-Identifier: GPL-2.0
# Copyright 2019 Jonathan Corbet <corbet@lwn.net>
#
# Apply kernel-specific tweaks after the initial document processing
# has been done.
#
from docutils import nodes
import sphinx
from sphinx import addnodes
if sphinx.version_info[0] < 2 or \
sphinx.version_info[0] == 2 and sphinx.version_info[1] < 1:
from sphinx.environment import NoUri
else:
from sphinx.errors import NoUri
import re
from itertools import chain
#
# Python 2 lacks re.ASCII...
#
try:
ascii_p3 = re.ASCII
except AttributeError:
ascii_p3 = 0
#
# Regex nastiness. Of course.
# Try to identify "function()" that's not already marked up some
# other way. Sphinx doesn't like a lot of stuff right after a
# :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'\b(([a-zA-Z_]\w+)\(\))', flags=ascii_p3)
#
# Sphinx 2 uses the same :c:type role for struct, union, enum and typedef
#
RE_generic_type = re.compile(r'\b(struct|union|enum|typedef)\s+([a-zA-Z_]\w+)',
flags=ascii_p3)
#
# Sphinx 3 uses a different C role for each one of struct, union, enum and
# typedef
#
RE_struct = re.compile(r'\b(struct)\s+([a-zA-Z_]\w+)', flags=ascii_p3)
RE_union = re.compile(r'\b(union)\s+([a-zA-Z_]\w+)', flags=ascii_p3)
RE_enum = re.compile(r'\b(enum)\s+([a-zA-Z_]\w+)', flags=ascii_p3)
RE_typedef = re.compile(r'\b(typedef)\s+([a-zA-Z_]\w+)', flags=ascii_p3)
#
# Detects a reference to a documentation page of the form Documentation/... with
# an optional extension
#
RE_doc = re.compile(r'\bDocumentation(/[\w\-_/]+)(\.\w+)*')
#
# Reserved C words that we should skip when cross-referencing
#
Skipnames = [ 'for', 'if', 'register', 'sizeof', 'struct', 'unsigned' ]
#
# Many places in the docs refer to common system calls. It is
# pointless to try to cross-reference them and, as has been known
# to happen, somebody defining a function by these names can lead
# to the creation of incorrect and confusing cross references. So
# just don't even try with these names.
#
Skipfuncs = [ 'open', 'close', 'read', 'write', 'fcntl', 'mmap',
'select', 'poll', 'fork', 'execve', 'clone', 'ioctl',
'socket' ]
def markup_refs(docname, app, node):
t = node.astext()
done = 0
repl = [ ]
#
# Associate each regex with the function that will markup its matches
#
markup_func_sphinx2 = {RE_doc: markup_doc_ref,
RE_function: markup_c_ref,
RE_generic_type: markup_c_ref}
markup_func_sphinx3 = {RE_doc: markup_doc_ref,
RE_function: markup_func_ref_sphinx3,
RE_struct: markup_c_ref,
RE_union: markup_c_ref,
RE_enum: markup_c_ref,
RE_typedef: markup_c_ref}
if sphinx.version_info[0] >= 3:
markup_func = markup_func_sphinx3
else:
markup_func = markup_func_sphinx2
match_iterators = [regex.finditer(t) for regex in markup_func]
#
# Sort all references by the starting position in text
#
sorted_matches = sorted(chain(*match_iterators), key=lambda m: m.start())
for m in sorted_matches:
#
# Include any text prior to match as a normal text node.
#
if m.start() > done:
repl.append(nodes.Text(t[done:m.start()]))
#
# Call the function associated with the regex that matched this text and
# append its return to the text
#
repl.append(markup_func[m.re](docname, app, m))
done = m.end()
if done < len(t):
repl.append(nodes.Text(t[done:]))
return repl
#
# In sphinx3 we can cross-reference to C macro and function, each one with its
# own C role, but both match the same regex, so we try both.
#
def markup_func_ref_sphinx3(docname, app, match):
class_str = ['c-func', 'c-macro']
reftype_str = ['function', 'macro']
cdom = app.env.domains['c']
#
# Go through the dance of getting an xref out of the C domain
#
target = match.group(2)
target_text = nodes.Text(match.group(0))
xref = None
if not (target in Skipfuncs or target in Skipnames):
for class_s, reftype_s in zip(class_str, reftype_str):
lit_text = nodes.literal(classes=['xref', 'c', class_s])
lit_text += target_text
pxref = addnodes.pending_xref('', refdomain = 'c',
reftype = reftype_s,
reftarget = target, modname = None,
classname = None)
#
# XXX The Latex builder will throw NoUri exceptions here,
# work around that by ignoring them.
#
try:
xref = cdom.resolve_xref(app.env, docname, app.builder,
reftype_s, target, pxref,
lit_text)
except NoUri:
xref = None
if xref:
return xref
return target_text
def markup_c_ref(docname, app, match):
class_str = {# Sphinx 2 only
RE_function: 'c-func',
RE_generic_type: 'c-type',
# Sphinx 3+ only
RE_struct: 'c-struct',
RE_union: 'c-union',
RE_enum: 'c-enum',
RE_typedef: 'c-type',
}
reftype_str = {# Sphinx 2 only
RE_function: 'function',
RE_generic_type: 'type',
# Sphinx 3+ only
RE_struct: 'struct',
RE_union: 'union',
RE_enum: 'enum',
RE_typedef: 'type',
}
cdom = app.env.domains['c']
#
# Go through the dance of getting an xref out of the C domain
#
target = match.group(2)
target_text = nodes.Text(match.group(0))
xref = None
if not ((match.re == RE_function and target in Skipfuncs)
or (target in Skipnames)):
lit_text = nodes.literal(classes=['xref', 'c', class_str[match.re]])
lit_text += target_text
pxref = addnodes.pending_xref('', refdomain = 'c',
reftype = reftype_str[match.re],
reftarget = target, modname = None,
classname = None)
#
# XXX The Latex builder will throw NoUri exceptions here,
# work around that by ignoring them.
#
try:
xref = cdom.resolve_xref(app.env, docname, app.builder,
reftype_str[match.re], target, pxref,
lit_text)
except NoUri:
xref = None
#
# Return the xref if we got it; otherwise just return the plain text.
#
if xref:
return xref
else:
return target_text
#
# Try to replace a documentation reference of the form Documentation/... with a
# cross reference to that page
#
def markup_doc_ref(docname, app, match):
stddom = app.env.domains['std']
#
# Go through the dance of getting an xref out of the std domain
#
target = match.group(1)
xref = None
pxref = addnodes.pending_xref('', refdomain = 'std', reftype = 'doc',
reftarget = target, modname = None,
classname = None, refexplicit = False)
#
# XXX The Latex builder will throw NoUri exceptions here,
# work around that by ignoring them.
#
try:
xref = stddom.resolve_xref(app.env, docname, app.builder, 'doc',
target, pxref, None)
except NoUri:
xref = None
#
# Return the xref if we got it; otherwise just return the plain text.
#
if xref:
return xref
else:
return nodes.Text(match.group(0))
def auto_markup(app, doctree, name):
#
# This loop could eventually be improved on. Someday maybe we
# want a proper tree traversal with a lot of awareness of which
# kinds of nodes to prune. But this works well for now.
#
# The nodes.literal test catches ``literal text``, its purpose is to
# avoid adding cross-references to functions that have been explicitly
# marked with cc:func:.
#
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_refs(name, app, node))
def setup(app):
app.connect('doctree-resolved', auto_markup)
return {
'parallel_read_safe': True,
'parallel_write_safe': True,
}
