1# coding=utf-8 2# 3# QEMU qapidoc QAPI file parsing extension 4# 5# Copyright (c) 2020 Linaro 6# 7# This work is licensed under the terms of the GNU GPLv2 or later. 8# See the COPYING file in the top-level directory. 9 10""" 11qapidoc is a Sphinx extension that implements the qapi-doc directive 12 13The purpose of this extension is to read the documentation comments 14in QAPI schema files, and insert them all into the current document. 15 16It implements one new rST directive, "qapi-doc::". 17Each qapi-doc:: directive takes one argument, which is the 18pathname of the schema file to process, relative to the source tree. 19 20The docs/conf.py file must set the qapidoc_srctree config value to 21the root of the QEMU source tree. 22 23The Sphinx documentation on writing extensions is at: 24https://www.sphinx-doc.org/en/master/development/index.html 25""" 26 27import os 28import re 29import textwrap 30 31from docutils import nodes 32from docutils.parsers.rst import Directive, directives 33from docutils.statemachine import ViewList 34from qapi.error import QAPIError, QAPISemError 35from qapi.gen import QAPISchemaVisitor 36from qapi.schema import QAPISchema 37 38from sphinx.errors import ExtensionError 39from sphinx.util.docutils import switch_source_input 40from sphinx.util.nodes import nested_parse_with_titles 41 42 43__version__ = "1.0" 44 45 46def dedent(text: str) -> str: 47 # Adjust indentation to make description text parse as paragraph. 48 49 lines = text.splitlines(True) 50 if re.match(r"\s+", lines[0]): 51 # First line is indented; description started on the line after 52 # the name. dedent the whole block. 53 return textwrap.dedent(text) 54 55 # Descr started on same line. Dedent line 2+. 56 return lines[0] + textwrap.dedent("".join(lines[1:])) 57 58 59# Disable black auto-formatter until re-enabled: 60# fmt: off 61 62 63class QAPISchemaGenRSTVisitor(QAPISchemaVisitor): 64 """A QAPI schema visitor which generates docutils/Sphinx nodes 65 66 This class builds up a tree of docutils/Sphinx nodes corresponding 67 to documentation for the various QAPI objects. To use it, first 68 create a QAPISchemaGenRSTVisitor object, and call its 69 visit_begin() method. Then you can call one of the two methods 70 'freeform' (to add documentation for a freeform documentation 71 chunk) or 'symbol' (to add documentation for a QAPI symbol). These 72 will cause the visitor to build up the tree of document 73 nodes. Once you've added all the documentation via 'freeform' and 74 'symbol' method calls, you can call 'get_document_nodes' to get 75 the final list of document nodes (in a form suitable for returning 76 from a Sphinx directive's 'run' method). 77 """ 78 def __init__(self, sphinx_directive): 79 self._cur_doc = None 80 self._sphinx_directive = sphinx_directive 81 self._top_node = nodes.section() 82 self._active_headings = [self._top_node] 83 84 def _make_dlitem(self, term, defn): 85 """Return a dlitem node with the specified term and definition. 86 87 term should be a list of Text and literal nodes. 88 defn should be one of: 89 - a string, which will be handed to _parse_text_into_node 90 - a list of Text and literal nodes, which will be put into 91 a paragraph node 92 """ 93 dlitem = nodes.definition_list_item() 94 dlterm = nodes.term('', '', *term) 95 dlitem += dlterm 96 if defn: 97 dldef = nodes.definition() 98 if isinstance(defn, list): 99 dldef += nodes.paragraph('', '', *defn) 100 else: 101 self._parse_text_into_node(defn, dldef) 102 dlitem += dldef 103 return dlitem 104 105 def _make_section(self, title): 106 """Return a section node with optional title""" 107 section = nodes.section(ids=[self._sphinx_directive.new_serialno()]) 108 if title: 109 section += nodes.title(title, title) 110 return section 111 112 def _nodes_for_ifcond(self, ifcond, with_if=True): 113 """Return list of Text, literal nodes for the ifcond 114 115 Return a list which gives text like ' (If: condition)'. 116 If with_if is False, we don't return the "(If: " and ")". 117 """ 118 119 doc = ifcond.docgen() 120 if not doc: 121 return [] 122 doc = nodes.literal('', doc) 123 if not with_if: 124 return [doc] 125 126 nodelist = [nodes.Text(' ('), nodes.strong('', 'If: ')] 127 nodelist.append(doc) 128 nodelist.append(nodes.Text(')')) 129 return nodelist 130 131 def _nodes_for_one_member(self, member): 132 """Return list of Text, literal nodes for this member 133 134 Return a list of doctree nodes which give text like 135 'name: type (optional) (If: ...)' suitable for use as the 136 'term' part of a definition list item. 137 """ 138 term = [nodes.literal('', member.name)] 139 if member.type.doc_type(): 140 term.append(nodes.Text(': ')) 141 term.append(nodes.literal('', member.type.doc_type())) 142 if member.optional: 143 term.append(nodes.Text(' (optional)')) 144 if member.ifcond.is_present(): 145 term.extend(self._nodes_for_ifcond(member.ifcond)) 146 return term 147 148 def _nodes_for_variant_when(self, branches, variant): 149 """Return list of Text, literal nodes for variant 'when' clause 150 151 Return a list of doctree nodes which give text like 152 'when tagname is variant (If: ...)' suitable for use in 153 the 'branches' part of a definition list. 154 """ 155 term = [nodes.Text(' when '), 156 nodes.literal('', branches.tag_member.name), 157 nodes.Text(' is '), 158 nodes.literal('', '"%s"' % variant.name)] 159 if variant.ifcond.is_present(): 160 term.extend(self._nodes_for_ifcond(variant.ifcond)) 161 return term 162 163 def _nodes_for_members(self, doc, what, base=None, branches=None): 164 """Return list of doctree nodes for the table of members""" 165 dlnode = nodes.definition_list() 166 for section in doc.args.values(): 167 term = self._nodes_for_one_member(section.member) 168 # TODO drop fallbacks when undocumented members are outlawed 169 if section.text: 170 defn = dedent(section.text) 171 else: 172 defn = [nodes.Text('Not documented')] 173 174 dlnode += self._make_dlitem(term, defn) 175 176 if base: 177 dlnode += self._make_dlitem([nodes.Text('The members of '), 178 nodes.literal('', base.doc_type())], 179 None) 180 181 if branches: 182 for v in branches.variants: 183 if v.type.name == 'q_empty': 184 continue 185 assert not v.type.is_implicit() 186 term = [nodes.Text('The members of '), 187 nodes.literal('', v.type.doc_type())] 188 term.extend(self._nodes_for_variant_when(branches, v)) 189 dlnode += self._make_dlitem(term, None) 190 191 if not dlnode.children: 192 return [] 193 194 section = self._make_section(what) 195 section += dlnode 196 return [section] 197 198 def _nodes_for_enum_values(self, doc): 199 """Return list of doctree nodes for the table of enum values""" 200 seen_item = False 201 dlnode = nodes.definition_list() 202 for section in doc.args.values(): 203 termtext = [nodes.literal('', section.member.name)] 204 if section.member.ifcond.is_present(): 205 termtext.extend(self._nodes_for_ifcond(section.member.ifcond)) 206 # TODO drop fallbacks when undocumented members are outlawed 207 if section.text: 208 defn = dedent(section.text) 209 else: 210 defn = [nodes.Text('Not documented')] 211 212 dlnode += self._make_dlitem(termtext, defn) 213 seen_item = True 214 215 if not seen_item: 216 return [] 217 218 section = self._make_section('Values') 219 section += dlnode 220 return [section] 221 222 def _nodes_for_arguments(self, doc, arg_type): 223 """Return list of doctree nodes for the arguments section""" 224 if arg_type and not arg_type.is_implicit(): 225 assert not doc.args 226 section = self._make_section('Arguments') 227 dlnode = nodes.definition_list() 228 dlnode += self._make_dlitem( 229 [nodes.Text('The members of '), 230 nodes.literal('', arg_type.name)], 231 None) 232 section += dlnode 233 return [section] 234 235 return self._nodes_for_members(doc, 'Arguments') 236 237 def _nodes_for_features(self, doc): 238 """Return list of doctree nodes for the table of features""" 239 seen_item = False 240 dlnode = nodes.definition_list() 241 for section in doc.features.values(): 242 dlnode += self._make_dlitem( 243 [nodes.literal('', section.member.name)], dedent(section.text)) 244 seen_item = True 245 246 if not seen_item: 247 return [] 248 249 section = self._make_section('Features') 250 section += dlnode 251 return [section] 252 253 def _nodes_for_example(self, exampletext): 254 """Return list of doctree nodes for a code example snippet""" 255 return [nodes.literal_block(exampletext, exampletext)] 256 257 def _nodes_for_sections(self, doc): 258 """Return list of doctree nodes for additional sections""" 259 nodelist = [] 260 for section in doc.sections: 261 if section.tag and section.tag == 'TODO': 262 # Hide TODO: sections 263 continue 264 265 if not section.tag: 266 # Sphinx cannot handle sectionless titles; 267 # Instead, just append the results to the prior section. 268 container = nodes.container() 269 self._parse_text_into_node(section.text, container) 270 nodelist += container.children 271 continue 272 273 snode = self._make_section(section.tag) 274 if section.tag.startswith('Example'): 275 snode += self._nodes_for_example(dedent(section.text)) 276 else: 277 self._parse_text_into_node(dedent(section.text), snode) 278 nodelist.append(snode) 279 return nodelist 280 281 def _nodes_for_if_section(self, ifcond): 282 """Return list of doctree nodes for the "If" section""" 283 nodelist = [] 284 if ifcond.is_present(): 285 snode = self._make_section('If') 286 snode += nodes.paragraph( 287 '', '', *self._nodes_for_ifcond(ifcond, with_if=False) 288 ) 289 nodelist.append(snode) 290 return nodelist 291 292 def _add_doc(self, typ, sections): 293 """Add documentation for a command/object/enum... 294 295 We assume we're documenting the thing defined in self._cur_doc. 296 typ is the type of thing being added ("Command", "Object", etc) 297 298 sections is a list of nodes for sections to add to the definition. 299 """ 300 301 doc = self._cur_doc 302 snode = nodes.section(ids=[self._sphinx_directive.new_serialno()]) 303 snode += nodes.title('', '', *[nodes.literal(doc.symbol, doc.symbol), 304 nodes.Text(' (' + typ + ')')]) 305 self._parse_text_into_node(doc.body.text, snode) 306 for s in sections: 307 if s is not None: 308 snode += s 309 self._add_node_to_current_heading(snode) 310 311 def visit_enum_type(self, name, info, ifcond, features, members, prefix): 312 doc = self._cur_doc 313 self._add_doc('Enum', 314 self._nodes_for_enum_values(doc) 315 + self._nodes_for_features(doc) 316 + self._nodes_for_sections(doc) 317 + self._nodes_for_if_section(ifcond)) 318 319 def visit_object_type(self, name, info, ifcond, features, 320 base, members, branches): 321 doc = self._cur_doc 322 if base and base.is_implicit(): 323 base = None 324 self._add_doc('Object', 325 self._nodes_for_members(doc, 'Members', base, branches) 326 + self._nodes_for_features(doc) 327 + self._nodes_for_sections(doc) 328 + self._nodes_for_if_section(ifcond)) 329 330 def visit_alternate_type(self, name, info, ifcond, features, 331 alternatives): 332 doc = self._cur_doc 333 self._add_doc('Alternate', 334 self._nodes_for_members(doc, 'Members') 335 + self._nodes_for_features(doc) 336 + self._nodes_for_sections(doc) 337 + self._nodes_for_if_section(ifcond)) 338 339 def visit_command(self, name, info, ifcond, features, arg_type, 340 ret_type, gen, success_response, boxed, allow_oob, 341 allow_preconfig, coroutine): 342 doc = self._cur_doc 343 self._add_doc('Command', 344 self._nodes_for_arguments(doc, arg_type) 345 + self._nodes_for_features(doc) 346 + self._nodes_for_sections(doc) 347 + self._nodes_for_if_section(ifcond)) 348 349 def visit_event(self, name, info, ifcond, features, arg_type, boxed): 350 doc = self._cur_doc 351 self._add_doc('Event', 352 self._nodes_for_arguments(doc, arg_type) 353 + self._nodes_for_features(doc) 354 + self._nodes_for_sections(doc) 355 + self._nodes_for_if_section(ifcond)) 356 357 def symbol(self, doc, entity): 358 """Add documentation for one symbol to the document tree 359 360 This is the main entry point which causes us to add documentation 361 nodes for a symbol (which could be a 'command', 'object', 'event', 362 etc). We do this by calling 'visit' on the schema entity, which 363 will then call back into one of our visit_* methods, depending 364 on what kind of thing this symbol is. 365 """ 366 self._cur_doc = doc 367 entity.visit(self) 368 self._cur_doc = None 369 370 def _start_new_heading(self, heading, level): 371 """Start a new heading at the specified heading level 372 373 Create a new section whose title is 'heading' and which is placed 374 in the docutils node tree as a child of the most recent level-1 375 heading. Subsequent document sections (commands, freeform doc chunks, 376 etc) will be placed as children of this new heading section. 377 """ 378 if len(self._active_headings) < level: 379 raise QAPISemError(self._cur_doc.info, 380 'Level %d subheading found outside a ' 381 'level %d heading' 382 % (level, level - 1)) 383 snode = self._make_section(heading) 384 self._active_headings[level - 1] += snode 385 self._active_headings = self._active_headings[:level] 386 self._active_headings.append(snode) 387 388 def _add_node_to_current_heading(self, node): 389 """Add the node to whatever the current active heading is""" 390 self._active_headings[-1] += node 391 392 def freeform(self, doc): 393 """Add a piece of 'freeform' documentation to the document tree 394 395 A 'freeform' document chunk doesn't relate to any particular 396 symbol (for instance, it could be an introduction). 397 398 If the freeform document starts with a line of the form 399 '= Heading text', this is a section or subsection heading, with 400 the heading level indicated by the number of '=' signs. 401 """ 402 403 # QAPIDoc documentation says free-form documentation blocks 404 # must have only a body section, nothing else. 405 assert not doc.sections 406 assert not doc.args 407 assert not doc.features 408 self._cur_doc = doc 409 410 text = doc.body.text 411 if re.match(r'=+ ', text): 412 # Section/subsection heading (if present, will always be 413 # the first line of the block) 414 (heading, _, text) = text.partition('\n') 415 (leader, _, heading) = heading.partition(' ') 416 self._start_new_heading(heading, len(leader)) 417 if text == '': 418 return 419 420 node = self._make_section(None) 421 self._parse_text_into_node(text, node) 422 self._add_node_to_current_heading(node) 423 self._cur_doc = None 424 425 def _parse_text_into_node(self, doctext, node): 426 """Parse a chunk of QAPI-doc-format text into the node 427 428 The doc comment can contain most inline rST markup, including 429 bulleted and enumerated lists. 430 As an extra permitted piece of markup, @var will be turned 431 into ``var``. 432 """ 433 434 # Handle the "@var means ``var`` case 435 doctext = re.sub(r'@([\w-]+)', r'``\1``', doctext) 436 437 rstlist = ViewList() 438 for line in doctext.splitlines(): 439 # The reported line number will always be that of the start line 440 # of the doc comment, rather than the actual location of the error. 441 # Being more precise would require overhaul of the QAPIDoc class 442 # to track lines more exactly within all the sub-parts of the doc 443 # comment, as well as counting lines here. 444 rstlist.append(line, self._cur_doc.info.fname, 445 self._cur_doc.info.line) 446 # Append a blank line -- in some cases rST syntax errors get 447 # attributed to the line after one with actual text, and if there 448 # isn't anything in the ViewList corresponding to that then Sphinx 449 # 1.6's AutodocReporter will then misidentify the source/line location 450 # in the error message (usually attributing it to the top-level 451 # .rst file rather than the offending .json file). The extra blank 452 # line won't affect the rendered output. 453 rstlist.append("", self._cur_doc.info.fname, self._cur_doc.info.line) 454 self._sphinx_directive.do_parse(rstlist, node) 455 456 def get_document_nodes(self): 457 """Return the list of docutils nodes which make up the document""" 458 return self._top_node.children 459 460 461# Turn the black formatter on for the rest of the file. 462# fmt: on 463 464 465class QAPISchemaGenDepVisitor(QAPISchemaVisitor): 466 """A QAPI schema visitor which adds Sphinx dependencies each module 467 468 This class calls the Sphinx note_dependency() function to tell Sphinx 469 that the generated documentation output depends on the input 470 schema file associated with each module in the QAPI input. 471 """ 472 473 def __init__(self, env, qapidir): 474 self._env = env 475 self._qapidir = qapidir 476 477 def visit_module(self, name): 478 if name != "./builtin": 479 qapifile = self._qapidir + "/" + name 480 self._env.note_dependency(os.path.abspath(qapifile)) 481 super().visit_module(name) 482 483 484class QAPIDocDirective(Directive): 485 """Extract documentation from the specified QAPI .json file""" 486 487 required_argument = 1 488 optional_arguments = 1 489 option_spec = {"qapifile": directives.unchanged_required} 490 has_content = False 491 492 def new_serialno(self): 493 """Return a unique new ID string suitable for use as a node's ID""" 494 env = self.state.document.settings.env 495 return "qapidoc-%d" % env.new_serialno("qapidoc") 496 497 def run(self): 498 env = self.state.document.settings.env 499 qapifile = env.config.qapidoc_srctree + "/" + self.arguments[0] 500 qapidir = os.path.dirname(qapifile) 501 502 try: 503 schema = QAPISchema(qapifile) 504 505 # First tell Sphinx about all the schema files that the 506 # output documentation depends on (including 'qapifile' itself) 507 schema.visit(QAPISchemaGenDepVisitor(env, qapidir)) 508 509 vis = QAPISchemaGenRSTVisitor(self) 510 vis.visit_begin(schema) 511 for doc in schema.docs: 512 if doc.symbol: 513 vis.symbol(doc, schema.lookup_entity(doc.symbol)) 514 else: 515 vis.freeform(doc) 516 return vis.get_document_nodes() 517 except QAPIError as err: 518 # Launder QAPI parse errors into Sphinx extension errors 519 # so they are displayed nicely to the user 520 raise ExtensionError(str(err)) from err 521 522 def do_parse(self, rstlist, node): 523 """Parse rST source lines and add them to the specified node 524 525 Take the list of rST source lines rstlist, parse them as 526 rST, and add the resulting docutils nodes as children of node. 527 The nodes are parsed in a way that allows them to include 528 subheadings (titles) without confusing the rendering of 529 anything else. 530 """ 531 with switch_source_input(self.state, rstlist): 532 nested_parse_with_titles(self.state, rstlist, node) 533 534 535def setup(app): 536 """Register qapi-doc directive with Sphinx""" 537 app.add_config_value("qapidoc_srctree", None, "env") 538 app.add_directive("qapi-doc", QAPIDocDirective) 539 540 return { 541 "version": __version__, 542 "parallel_read_safe": True, 543 "parallel_write_safe": True, 544 } 545