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1# SPDX-License-Identifier: GPL-2.0
2# Copyright 2019 Jonathan Corbet <corbet@lwn.net>
3#
4# Apply kernel-specific tweaks after the initial document processing
5# has been done.
6#
7from docutils import nodes
8from sphinx import addnodes
9from sphinx.environment import NoUri
10import re
11
12#
13# Regex nastiness. Of course.
14# Try to identify "function()" that's not already marked up some
15# other way. Sphinx doesn't like a lot of stuff right after a
16# :c:func: block (i.e. ":c:func:`mmap()`s" flakes out), so the last
17# bit tries to restrict matches to things that won't create trouble.
18#
19RE_function = re.compile(r'([\w_][\w\d_]+\(\))')
20
21#
22# Many places in the docs refer to common system calls. It is
23# pointless to try to cross-reference them and, as has been known
24# to happen, somebody defining a function by these names can lead
25# to the creation of incorrect and confusing cross references. So
26# just don't even try with these names.
27#
28Skipfuncs = [ 'open', 'close', 'read', 'write', 'fcntl', 'mmap',
29 'select', 'poll', 'fork', 'execve', 'clone', 'ioctl',
30 'socket' ]
31
32#
33# Find all occurrences of function() and try to replace them with
34# appropriate cross references.
35#
36def markup_funcs(docname, app, node):
37 cdom = app.env.domains['c']
38 t = node.astext()
39 done = 0
40 repl = [ ]
41 for m in RE_function.finditer(t):
42 #
43 # Include any text prior to function() as a normal text node.
44 #
45 if m.start() > done:
46 repl.append(nodes.Text(t[done:m.start()]))
47 #
48 # Go through the dance of getting an xref out of the C domain
49 #
50 target = m.group(1)[:-2]
51 target_text = nodes.Text(target + '()')
52 xref = None
53 if target not in Skipfuncs:
54 lit_text = nodes.literal(classes=['xref', 'c', 'c-func'])
55 lit_text += target_text
56 pxref = addnodes.pending_xref('', refdomain = 'c',
57 reftype = 'function',
58 reftarget = target, modname = None,
59 classname = None)
60 #
61 # XXX The Latex builder will throw NoUri exceptions here,
62 # work around that by ignoring them.
63 #
64 try:
65 xref = cdom.resolve_xref(app.env, docname, app.builder,
66 'function', target, pxref, lit_text)
67 except NoUri:
68 xref = None
69 #
70 # Toss the xref into the list if we got it; otherwise just put
71 # the function text.
72 #
73 if xref:
74 repl.append(xref)
75 else:
76 repl.append(target_text)
77 done = m.end()
78 if done < len(t):
79 repl.append(nodes.Text(t[done:]))
80 return repl
81
82def auto_markup(app, doctree, name):
83 #
84 # This loop could eventually be improved on. Someday maybe we
85 # want a proper tree traversal with a lot of awareness of which
86 # kinds of nodes to prune. But this works well for now.
87 #
88 # The nodes.literal test catches ``literal text``, its purpose is to
89 # avoid adding cross-references to functions that have been explicitly
90 # marked with cc:func:.
91 #
92 for para in doctree.traverse(nodes.paragraph):
93 for node in para.traverse(nodes.Text):
94 if not isinstance(node.parent, nodes.literal):
95 node.parent.replace(node, markup_funcs(name, app, node))
96
97def setup(app):
98 app.connect('doctree-resolved', auto_markup)
99 return {
100 'parallel_read_safe': True,
101 'parallel_write_safe': True,
102 }
1# SPDX-License-Identifier: GPL-2.0
2# Copyright 2019 Jonathan Corbet <corbet@lwn.net>
3#
4# Apply kernel-specific tweaks after the initial document processing
5# has been done.
6#
7from docutils import nodes
8import sphinx
9from sphinx import addnodes
10if sphinx.version_info[0] < 2 or \
11 sphinx.version_info[0] == 2 and sphinx.version_info[1] < 1:
12 from sphinx.environment import NoUri
13else:
14 from sphinx.errors import NoUri
15import re
16from itertools import chain
17
18#
19# Python 2 lacks re.ASCII...
20#
21try:
22 ascii_p3 = re.ASCII
23except AttributeError:
24 ascii_p3 = 0
25
26#
27# Regex nastiness. Of course.
28# Try to identify "function()" that's not already marked up some
29# other way. Sphinx doesn't like a lot of stuff right after a
30# :c:func: block (i.e. ":c:func:`mmap()`s" flakes out), so the last
31# bit tries to restrict matches to things that won't create trouble.
32#
33RE_function = re.compile(r'\b(([a-zA-Z_]\w+)\(\))', flags=ascii_p3)
34
35#
36# Sphinx 2 uses the same :c:type role for struct, union, enum and typedef
37#
38RE_generic_type = re.compile(r'\b(struct|union|enum|typedef)\s+([a-zA-Z_]\w+)',
39 flags=ascii_p3)
40
41#
42# Sphinx 3 uses a different C role for each one of struct, union, enum and
43# typedef
44#
45RE_struct = re.compile(r'\b(struct)\s+([a-zA-Z_]\w+)', flags=ascii_p3)
46RE_union = re.compile(r'\b(union)\s+([a-zA-Z_]\w+)', flags=ascii_p3)
47RE_enum = re.compile(r'\b(enum)\s+([a-zA-Z_]\w+)', flags=ascii_p3)
48RE_typedef = re.compile(r'\b(typedef)\s+([a-zA-Z_]\w+)', flags=ascii_p3)
49
50#
51# Detects a reference to a documentation page of the form Documentation/... with
52# an optional extension
53#
54RE_doc = re.compile(r'(\bDocumentation/)?((\.\./)*[\w\-/]+)\.(rst|txt)')
55
56RE_namespace = re.compile(r'^\s*..\s*c:namespace::\s*(\S+)\s*$')
57
58#
59# Reserved C words that we should skip when cross-referencing
60#
61Skipnames = [ 'for', 'if', 'register', 'sizeof', 'struct', 'unsigned' ]
62
63
64#
65# Many places in the docs refer to common system calls. It is
66# pointless to try to cross-reference them and, as has been known
67# to happen, somebody defining a function by these names can lead
68# to the creation of incorrect and confusing cross references. So
69# just don't even try with these names.
70#
71Skipfuncs = [ 'open', 'close', 'read', 'write', 'fcntl', 'mmap',
72 'select', 'poll', 'fork', 'execve', 'clone', 'ioctl',
73 'socket' ]
74
75c_namespace = ''
76
77def markup_refs(docname, app, node):
78 t = node.astext()
79 done = 0
80 repl = [ ]
81 #
82 # Associate each regex with the function that will markup its matches
83 #
84 markup_func_sphinx2 = {RE_doc: markup_doc_ref,
85 RE_function: markup_c_ref,
86 RE_generic_type: markup_c_ref}
87
88 markup_func_sphinx3 = {RE_doc: markup_doc_ref,
89 RE_function: markup_func_ref_sphinx3,
90 RE_struct: markup_c_ref,
91 RE_union: markup_c_ref,
92 RE_enum: markup_c_ref,
93 RE_typedef: markup_c_ref}
94
95 if sphinx.version_info[0] >= 3:
96 markup_func = markup_func_sphinx3
97 else:
98 markup_func = markup_func_sphinx2
99
100 match_iterators = [regex.finditer(t) for regex in markup_func]
101 #
102 # Sort all references by the starting position in text
103 #
104 sorted_matches = sorted(chain(*match_iterators), key=lambda m: m.start())
105 for m in sorted_matches:
106 #
107 # Include any text prior to match as a normal text node.
108 #
109 if m.start() > done:
110 repl.append(nodes.Text(t[done:m.start()]))
111
112 #
113 # Call the function associated with the regex that matched this text and
114 # append its return to the text
115 #
116 repl.append(markup_func[m.re](docname, app, m))
117
118 done = m.end()
119 if done < len(t):
120 repl.append(nodes.Text(t[done:]))
121 return repl
122
123#
124# Keep track of cross-reference lookups that failed so we don't have to
125# do them again.
126#
127failed_lookups = { }
128def failure_seen(target):
129 return (target) in failed_lookups
130def note_failure(target):
131 failed_lookups[target] = True
132
133#
134# In sphinx3 we can cross-reference to C macro and function, each one with its
135# own C role, but both match the same regex, so we try both.
136#
137def markup_func_ref_sphinx3(docname, app, match):
138 cdom = app.env.domains['c']
139 #
140 # Go through the dance of getting an xref out of the C domain
141 #
142 base_target = match.group(2)
143 target_text = nodes.Text(match.group(0))
144 xref = None
145 possible_targets = [base_target]
146 # Check if this document has a namespace, and if so, try
147 # cross-referencing inside it first.
148 if c_namespace:
149 possible_targets.insert(0, c_namespace + "." + base_target)
150
151 if base_target not in Skipnames:
152 for target in possible_targets:
153 if (target not in Skipfuncs) and not failure_seen(target):
154 lit_text = nodes.literal(classes=['xref', 'c', 'c-func'])
155 lit_text += target_text
156 pxref = addnodes.pending_xref('', refdomain = 'c',
157 reftype = 'function',
158 reftarget = target,
159 modname = None,
160 classname = None)
161 #
162 # XXX The Latex builder will throw NoUri exceptions here,
163 # work around that by ignoring them.
164 #
165 try:
166 xref = cdom.resolve_xref(app.env, docname, app.builder,
167 'function', target, pxref,
168 lit_text)
169 except NoUri:
170 xref = None
171
172 if xref:
173 return xref
174 note_failure(target)
175
176 return target_text
177
178def markup_c_ref(docname, app, match):
179 class_str = {# Sphinx 2 only
180 RE_function: 'c-func',
181 RE_generic_type: 'c-type',
182 # Sphinx 3+ only
183 RE_struct: 'c-struct',
184 RE_union: 'c-union',
185 RE_enum: 'c-enum',
186 RE_typedef: 'c-type',
187 }
188 reftype_str = {# Sphinx 2 only
189 RE_function: 'function',
190 RE_generic_type: 'type',
191 # Sphinx 3+ only
192 RE_struct: 'struct',
193 RE_union: 'union',
194 RE_enum: 'enum',
195 RE_typedef: 'type',
196 }
197
198 cdom = app.env.domains['c']
199 #
200 # Go through the dance of getting an xref out of the C domain
201 #
202 base_target = match.group(2)
203 target_text = nodes.Text(match.group(0))
204 xref = None
205 possible_targets = [base_target]
206 # Check if this document has a namespace, and if so, try
207 # cross-referencing inside it first.
208 if c_namespace:
209 possible_targets.insert(0, c_namespace + "." + base_target)
210
211 if base_target not in Skipnames:
212 for target in possible_targets:
213 if not (match.re == RE_function and target in Skipfuncs):
214 lit_text = nodes.literal(classes=['xref', 'c', class_str[match.re]])
215 lit_text += target_text
216 pxref = addnodes.pending_xref('', refdomain = 'c',
217 reftype = reftype_str[match.re],
218 reftarget = target, modname = None,
219 classname = None)
220 #
221 # XXX The Latex builder will throw NoUri exceptions here,
222 # work around that by ignoring them.
223 #
224 try:
225 xref = cdom.resolve_xref(app.env, docname, app.builder,
226 reftype_str[match.re], target, pxref,
227 lit_text)
228 except NoUri:
229 xref = None
230
231 if xref:
232 return xref
233
234 return target_text
235
236#
237# Try to replace a documentation reference of the form Documentation/... with a
238# cross reference to that page
239#
240def markup_doc_ref(docname, app, match):
241 stddom = app.env.domains['std']
242 #
243 # Go through the dance of getting an xref out of the std domain
244 #
245 absolute = match.group(1)
246 target = match.group(2)
247 if absolute:
248 target = "/" + target
249 xref = None
250 pxref = addnodes.pending_xref('', refdomain = 'std', reftype = 'doc',
251 reftarget = target, modname = None,
252 classname = None, refexplicit = False)
253 #
254 # XXX The Latex builder will throw NoUri exceptions here,
255 # work around that by ignoring them.
256 #
257 try:
258 xref = stddom.resolve_xref(app.env, docname, app.builder, 'doc',
259 target, pxref, None)
260 except NoUri:
261 xref = None
262 #
263 # Return the xref if we got it; otherwise just return the plain text.
264 #
265 if xref:
266 return xref
267 else:
268 return nodes.Text(match.group(0))
269
270def get_c_namespace(app, docname):
271 source = app.env.doc2path(docname)
272 with open(source) as f:
273 for l in f:
274 match = RE_namespace.search(l)
275 if match:
276 return match.group(1)
277 return ''
278
279def auto_markup(app, doctree, name):
280 global c_namespace
281 c_namespace = get_c_namespace(app, name)
282 def text_but_not_a_reference(node):
283 # The nodes.literal test catches ``literal text``, its purpose is to
284 # avoid adding cross-references to functions that have been explicitly
285 # marked with cc:func:.
286 if not isinstance(node, nodes.Text) or isinstance(node.parent, nodes.literal):
287 return False
288
289 child_of_reference = False
290 parent = node.parent
291 while parent:
292 if isinstance(parent, nodes.Referential):
293 child_of_reference = True
294 break
295 parent = parent.parent
296 return not child_of_reference
297
298 #
299 # This loop could eventually be improved on. Someday maybe we
300 # want a proper tree traversal with a lot of awareness of which
301 # kinds of nodes to prune. But this works well for now.
302 #
303 for para in doctree.traverse(nodes.paragraph):
304 for node in para.traverse(condition=text_but_not_a_reference):
305 node.parent.replace(node, markup_refs(name, app, node))
306
307def setup(app):
308 app.connect('doctree-resolved', auto_markup)
309 return {
310 'parallel_read_safe': True,
311 'parallel_write_safe': True,
312 }