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# In sphinx3 we can cross-reference to C macro and function, each one with its 125# own C role, but both match the same regex, so we try both. 126# 127def markup_func_ref_sphinx3(docname, app, match): 128 class_str = ['c-func', 'c-macro'] 129 reftype_str = ['function', 'macro'] 130 131 cdom = app.env.domains['c'] 132 # 133 # Go through the dance of getting an xref out of the C domain 134 # 135 base_target = match.group(2) 136 target_text = nodes.Text(match.group(0)) 137 xref = None 138 possible_targets = [base_target] 139 # Check if this document has a namespace, and if so, try 140 # cross-referencing inside it first. 141 if c_namespace: 142 possible_targets.insert(0, c_namespace + "." + base_target) 143 144 if base_target not in Skipnames: 145 for target in possible_targets: 146 if target not in Skipfuncs: 147 for class_s, reftype_s in zip(class_str, reftype_str): 148 lit_text = nodes.literal(classes=['xref', 'c', class_s]) 149 lit_text += target_text 150 pxref = addnodes.pending_xref('', refdomain = 'c', 151 reftype = reftype_s, 152 reftarget = target, modname = None, 153 classname = None) 154 # 155 # XXX The Latex builder will throw NoUri exceptions here, 156 # work around that by ignoring them. 157 # 158 try: 159 xref = cdom.resolve_xref(app.env, docname, app.builder, 160 reftype_s, target, pxref, 161 lit_text) 162 except NoUri: 163 xref = None 164 165 if xref: 166 return xref 167 168 return target_text 169 170def markup_c_ref(docname, app, match): 171 class_str = {# Sphinx 2 only 172 RE_function: 'c-func', 173 RE_generic_type: 'c-type', 174 # Sphinx 3+ only 175 RE_struct: 'c-struct', 176 RE_union: 'c-union', 177 RE_enum: 'c-enum', 178 RE_typedef: 'c-type', 179 } 180 reftype_str = {# Sphinx 2 only 181 RE_function: 'function', 182 RE_generic_type: 'type', 183 # Sphinx 3+ only 184 RE_struct: 'struct', 185 RE_union: 'union', 186 RE_enum: 'enum', 187 RE_typedef: 'type', 188 } 189 190 cdom = app.env.domains['c'] 191 # 192 # Go through the dance of getting an xref out of the C domain 193 # 194 base_target = match.group(2) 195 target_text = nodes.Text(match.group(0)) 196 xref = None 197 possible_targets = [base_target] 198 # Check if this document has a namespace, and if so, try 199 # cross-referencing inside it first. 200 if c_namespace: 201 possible_targets.insert(0, c_namespace + "." + base_target) 202 203 if base_target not in Skipnames: 204 for target in possible_targets: 205 if not (match.re == RE_function and target in Skipfuncs): 206 lit_text = nodes.literal(classes=['xref', 'c', class_str[match.re]]) 207 lit_text += target_text 208 pxref = addnodes.pending_xref('', refdomain = 'c', 209 reftype = reftype_str[match.re], 210 reftarget = target, modname = None, 211 classname = None) 212 # 213 # XXX The Latex builder will throw NoUri exceptions here, 214 # work around that by ignoring them. 215 # 216 try: 217 xref = cdom.resolve_xref(app.env, docname, app.builder, 218 reftype_str[match.re], target, pxref, 219 lit_text) 220 except NoUri: 221 xref = None 222 223 if xref: 224 return xref 225 226 return target_text 227 228# 229# Try to replace a documentation reference of the form Documentation/... with a 230# cross reference to that page 231# 232def markup_doc_ref(docname, app, match): 233 stddom = app.env.domains['std'] 234 # 235 # Go through the dance of getting an xref out of the std domain 236 # 237 absolute = match.group(1) 238 target = match.group(2) 239 if absolute: 240 target = "/" + target 241 xref = None 242 pxref = addnodes.pending_xref('', refdomain = 'std', reftype = 'doc', 243 reftarget = target, modname = None, 244 classname = None, refexplicit = False) 245 # 246 # XXX The Latex builder will throw NoUri exceptions here, 247 # work around that by ignoring them. 248 # 249 try: 250 xref = stddom.resolve_xref(app.env, docname, app.builder, 'doc', 251 target, pxref, None) 252 except NoUri: 253 xref = None 254 # 255 # Return the xref if we got it; otherwise just return the plain text. 256 # 257 if xref: 258 return xref 259 else: 260 return nodes.Text(match.group(0)) 261 262def get_c_namespace(app, docname): 263 source = app.env.doc2path(docname) 264 with open(source) as f: 265 for l in f: 266 match = RE_namespace.search(l) 267 if match: 268 return match.group(1) 269 return '' 270 271def auto_markup(app, doctree, name): 272 global c_namespace 273 c_namespace = get_c_namespace(app, name) 274 # 275 # This loop could eventually be improved on. Someday maybe we 276 # want a proper tree traversal with a lot of awareness of which 277 # kinds of nodes to prune. But this works well for now. 278 # 279 # The nodes.literal test catches ``literal text``, its purpose is to 280 # avoid adding cross-references to functions that have been explicitly 281 # marked with cc:func:. 282 # 283 for para in doctree.traverse(nodes.paragraph): 284 for node in para.traverse(nodes.Text): 285 if not isinstance(node.parent, nodes.literal): 286 node.parent.replace(node, markup_refs(name, app, node)) 287 288def setup(app): 289 app.connect('doctree-resolved', auto_markup) 290 return { 291 'parallel_read_safe': True, 292 'parallel_write_safe': True, 293 } 294