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 sys 30import textwrap 31from typing import List 32 33from docutils import nodes 34from docutils.parsers.rst import Directive, directives 35from docutils.statemachine import ViewList 36from qapi.error import QAPIError, QAPISemError 37from qapi.gen import QAPISchemaVisitor 38from qapi.schema import QAPISchema 39 40from sphinx import addnodes 41from sphinx.directives.code import CodeBlock 42from sphinx.errors import ExtensionError 43from sphinx.util.docutils import switch_source_input 44from sphinx.util.nodes import nested_parse_with_titles 45 46 47__version__ = "1.0" 48 49 50def dedent(text: str) -> str: 51 # Adjust indentation to make description text parse as paragraph. 52 53 lines = text.splitlines(True) 54 if re.match(r"\s+", lines[0]): 55 # First line is indented; description started on the line after 56 # the name. dedent the whole block. 57 return textwrap.dedent(text) 58 59 # Descr started on same line. Dedent line 2+. 60 return lines[0] + textwrap.dedent("".join(lines[1:])) 61 62 63# Disable black auto-formatter until re-enabled: 64# fmt: off 65 66 67class QAPISchemaGenRSTVisitor(QAPISchemaVisitor): 68 """A QAPI schema visitor which generates docutils/Sphinx nodes 69 70 This class builds up a tree of docutils/Sphinx nodes corresponding 71 to documentation for the various QAPI objects. To use it, first 72 create a QAPISchemaGenRSTVisitor object, and call its 73 visit_begin() method. Then you can call one of the two methods 74 'freeform' (to add documentation for a freeform documentation 75 chunk) or 'symbol' (to add documentation for a QAPI symbol). These 76 will cause the visitor to build up the tree of document 77 nodes. Once you've added all the documentation via 'freeform' and 78 'symbol' method calls, you can call 'get_document_nodes' to get 79 the final list of document nodes (in a form suitable for returning 80 from a Sphinx directive's 'run' method). 81 """ 82 def __init__(self, sphinx_directive): 83 self._cur_doc = None 84 self._sphinx_directive = sphinx_directive 85 self._top_node = nodes.section() 86 self._active_headings = [self._top_node] 87 88 def _make_dlitem(self, term, defn): 89 """Return a dlitem node with the specified term and definition. 90 91 term should be a list of Text and literal nodes. 92 defn should be one of: 93 - a string, which will be handed to _parse_text_into_node 94 - a list of Text and literal nodes, which will be put into 95 a paragraph node 96 """ 97 dlitem = nodes.definition_list_item() 98 dlterm = nodes.term('', '', *term) 99 dlitem += dlterm 100 if defn: 101 dldef = nodes.definition() 102 if isinstance(defn, list): 103 dldef += nodes.paragraph('', '', *defn) 104 else: 105 self._parse_text_into_node(defn, dldef) 106 dlitem += dldef 107 return dlitem 108 109 def _make_section(self, title): 110 """Return a section node with optional title""" 111 section = nodes.section(ids=[self._sphinx_directive.new_serialno()]) 112 if title: 113 section += nodes.title(title, title) 114 return section 115 116 def _nodes_for_ifcond(self, ifcond, with_if=True): 117 """Return list of Text, literal nodes for the ifcond 118 119 Return a list which gives text like ' (If: condition)'. 120 If with_if is False, we don't return the "(If: " and ")". 121 """ 122 123 doc = ifcond.docgen() 124 if not doc: 125 return [] 126 doc = nodes.literal('', doc) 127 if not with_if: 128 return [doc] 129 130 nodelist = [nodes.Text(' ('), nodes.strong('', 'If: ')] 131 nodelist.append(doc) 132 nodelist.append(nodes.Text(')')) 133 return nodelist 134 135 def _nodes_for_one_member(self, member): 136 """Return list of Text, literal nodes for this member 137 138 Return a list of doctree nodes which give text like 139 'name: type (optional) (If: ...)' suitable for use as the 140 'term' part of a definition list item. 141 """ 142 term = [nodes.literal('', member.name)] 143 if member.type.doc_type(): 144 term.append(nodes.Text(': ')) 145 term.append(nodes.literal('', member.type.doc_type())) 146 if member.optional: 147 term.append(nodes.Text(' (optional)')) 148 if member.ifcond.is_present(): 149 term.extend(self._nodes_for_ifcond(member.ifcond)) 150 return term 151 152 def _nodes_for_variant_when(self, branches, variant): 153 """Return list of Text, literal nodes for variant 'when' clause 154 155 Return a list of doctree nodes which give text like 156 'when tagname is variant (If: ...)' suitable for use in 157 the 'branches' part of a definition list. 158 """ 159 term = [nodes.Text(' when '), 160 nodes.literal('', branches.tag_member.name), 161 nodes.Text(' is '), 162 nodes.literal('', '"%s"' % variant.name)] 163 if variant.ifcond.is_present(): 164 term.extend(self._nodes_for_ifcond(variant.ifcond)) 165 return term 166 167 def _nodes_for_members(self, doc, what, base=None, branches=None): 168 """Return list of doctree nodes for the table of members""" 169 dlnode = nodes.definition_list() 170 for section in doc.args.values(): 171 term = self._nodes_for_one_member(section.member) 172 # TODO drop fallbacks when undocumented members are outlawed 173 if section.text: 174 defn = dedent(section.text) 175 else: 176 defn = [nodes.Text('Not documented')] 177 178 dlnode += self._make_dlitem(term, defn) 179 180 if base: 181 dlnode += self._make_dlitem([nodes.Text('The members of '), 182 nodes.literal('', base.doc_type())], 183 None) 184 185 if branches: 186 for v in branches.variants: 187 if v.type.name == 'q_empty': 188 continue 189 assert not v.type.is_implicit() 190 term = [nodes.Text('The members of '), 191 nodes.literal('', v.type.doc_type())] 192 term.extend(self._nodes_for_variant_when(branches, v)) 193 dlnode += self._make_dlitem(term, None) 194 195 if not dlnode.children: 196 return [] 197 198 section = self._make_section(what) 199 section += dlnode 200 return [section] 201 202 def _nodes_for_enum_values(self, doc): 203 """Return list of doctree nodes for the table of enum values""" 204 seen_item = False 205 dlnode = nodes.definition_list() 206 for section in doc.args.values(): 207 termtext = [nodes.literal('', section.member.name)] 208 if section.member.ifcond.is_present(): 209 termtext.extend(self._nodes_for_ifcond(section.member.ifcond)) 210 # TODO drop fallbacks when undocumented members are outlawed 211 if section.text: 212 defn = dedent(section.text) 213 else: 214 defn = [nodes.Text('Not documented')] 215 216 dlnode += self._make_dlitem(termtext, defn) 217 seen_item = True 218 219 if not seen_item: 220 return [] 221 222 section = self._make_section('Values') 223 section += dlnode 224 return [section] 225 226 def _nodes_for_arguments(self, doc, arg_type): 227 """Return list of doctree nodes for the arguments section""" 228 if arg_type and not arg_type.is_implicit(): 229 assert not doc.args 230 section = self._make_section('Arguments') 231 dlnode = nodes.definition_list() 232 dlnode += self._make_dlitem( 233 [nodes.Text('The members of '), 234 nodes.literal('', arg_type.name)], 235 None) 236 section += dlnode 237 return [section] 238 239 return self._nodes_for_members(doc, 'Arguments') 240 241 def _nodes_for_features(self, doc): 242 """Return list of doctree nodes for the table of features""" 243 seen_item = False 244 dlnode = nodes.definition_list() 245 for section in doc.features.values(): 246 dlnode += self._make_dlitem( 247 [nodes.literal('', section.member.name)], dedent(section.text)) 248 seen_item = True 249 250 if not seen_item: 251 return [] 252 253 section = self._make_section('Features') 254 section += dlnode 255 return [section] 256 257 def _nodes_for_example(self, exampletext): 258 """Return list of doctree nodes for a code example snippet""" 259 return [nodes.literal_block(exampletext, exampletext)] 260 261 def _nodes_for_sections(self, doc): 262 """Return list of doctree nodes for additional sections""" 263 nodelist = [] 264 for section in doc.sections: 265 if section.tag and section.tag == 'TODO': 266 # Hide TODO: sections 267 continue 268 269 if not section.tag: 270 # Sphinx cannot handle sectionless titles; 271 # Instead, just append the results to the prior section. 272 container = nodes.container() 273 self._parse_text_into_node(section.text, container) 274 nodelist += container.children 275 continue 276 277 snode = self._make_section(section.tag) 278 if section.tag.startswith('Example'): 279 snode += self._nodes_for_example(dedent(section.text)) 280 else: 281 self._parse_text_into_node(dedent(section.text), snode) 282 nodelist.append(snode) 283 return nodelist 284 285 def _nodes_for_if_section(self, ifcond): 286 """Return list of doctree nodes for the "If" section""" 287 nodelist = [] 288 if ifcond.is_present(): 289 snode = self._make_section('If') 290 snode += nodes.paragraph( 291 '', '', *self._nodes_for_ifcond(ifcond, with_if=False) 292 ) 293 nodelist.append(snode) 294 return nodelist 295 296 def _add_doc(self, typ, sections): 297 """Add documentation for a command/object/enum... 298 299 We assume we're documenting the thing defined in self._cur_doc. 300 typ is the type of thing being added ("Command", "Object", etc) 301 302 sections is a list of nodes for sections to add to the definition. 303 """ 304 305 doc = self._cur_doc 306 snode = nodes.section(ids=[self._sphinx_directive.new_serialno()]) 307 snode += nodes.title('', '', *[nodes.literal(doc.symbol, doc.symbol), 308 nodes.Text(' (' + typ + ')')]) 309 self._parse_text_into_node(doc.body.text, snode) 310 for s in sections: 311 if s is not None: 312 snode += s 313 self._add_node_to_current_heading(snode) 314 315 def visit_enum_type(self, name, info, ifcond, features, members, prefix): 316 doc = self._cur_doc 317 self._add_doc('Enum', 318 self._nodes_for_enum_values(doc) 319 + self._nodes_for_features(doc) 320 + self._nodes_for_sections(doc) 321 + self._nodes_for_if_section(ifcond)) 322 323 def visit_object_type(self, name, info, ifcond, features, 324 base, members, branches): 325 doc = self._cur_doc 326 if base and base.is_implicit(): 327 base = None 328 self._add_doc('Object', 329 self._nodes_for_members(doc, 'Members', base, branches) 330 + self._nodes_for_features(doc) 331 + self._nodes_for_sections(doc) 332 + self._nodes_for_if_section(ifcond)) 333 334 def visit_alternate_type(self, name, info, ifcond, features, 335 alternatives): 336 doc = self._cur_doc 337 self._add_doc('Alternate', 338 self._nodes_for_members(doc, 'Members') 339 + self._nodes_for_features(doc) 340 + self._nodes_for_sections(doc) 341 + self._nodes_for_if_section(ifcond)) 342 343 def visit_command(self, name, info, ifcond, features, arg_type, 344 ret_type, gen, success_response, boxed, allow_oob, 345 allow_preconfig, coroutine): 346 doc = self._cur_doc 347 self._add_doc('Command', 348 self._nodes_for_arguments(doc, arg_type) 349 + self._nodes_for_features(doc) 350 + self._nodes_for_sections(doc) 351 + self._nodes_for_if_section(ifcond)) 352 353 def visit_event(self, name, info, ifcond, features, arg_type, boxed): 354 doc = self._cur_doc 355 self._add_doc('Event', 356 self._nodes_for_arguments(doc, arg_type) 357 + self._nodes_for_features(doc) 358 + self._nodes_for_sections(doc) 359 + self._nodes_for_if_section(ifcond)) 360 361 def symbol(self, doc, entity): 362 """Add documentation for one symbol to the document tree 363 364 This is the main entry point which causes us to add documentation 365 nodes for a symbol (which could be a 'command', 'object', 'event', 366 etc). We do this by calling 'visit' on the schema entity, which 367 will then call back into one of our visit_* methods, depending 368 on what kind of thing this symbol is. 369 """ 370 self._cur_doc = doc 371 entity.visit(self) 372 self._cur_doc = None 373 374 def _start_new_heading(self, heading, level): 375 """Start a new heading at the specified heading level 376 377 Create a new section whose title is 'heading' and which is placed 378 in the docutils node tree as a child of the most recent level-1 379 heading. Subsequent document sections (commands, freeform doc chunks, 380 etc) will be placed as children of this new heading section. 381 """ 382 if len(self._active_headings) < level: 383 raise QAPISemError(self._cur_doc.info, 384 'Level %d subheading found outside a ' 385 'level %d heading' 386 % (level, level - 1)) 387 snode = self._make_section(heading) 388 self._active_headings[level - 1] += snode 389 self._active_headings = self._active_headings[:level] 390 self._active_headings.append(snode) 391 return snode 392 393 def _add_node_to_current_heading(self, node): 394 """Add the node to whatever the current active heading is""" 395 self._active_headings[-1] += node 396 397 def freeform(self, doc): 398 """Add a piece of 'freeform' documentation to the document tree 399 400 A 'freeform' document chunk doesn't relate to any particular 401 symbol (for instance, it could be an introduction). 402 403 If the freeform document starts with a line of the form 404 '= Heading text', this is a section or subsection heading, with 405 the heading level indicated by the number of '=' signs. 406 """ 407 408 # QAPIDoc documentation says free-form documentation blocks 409 # must have only a body section, nothing else. 410 assert not doc.sections 411 assert not doc.args 412 assert not doc.features 413 self._cur_doc = doc 414 415 text = doc.body.text 416 if re.match(r'=+ ', text): 417 # Section/subsection heading (if present, will always be 418 # the first line of the block) 419 (heading, _, text) = text.partition('\n') 420 (leader, _, heading) = heading.partition(' ') 421 node = self._start_new_heading(heading, len(leader)) 422 if text == '': 423 return 424 else: 425 node = nodes.container() 426 427 self._parse_text_into_node(text, node) 428 self._cur_doc = None 429 430 def _parse_text_into_node(self, doctext, node): 431 """Parse a chunk of QAPI-doc-format text into the node 432 433 The doc comment can contain most inline rST markup, including 434 bulleted and enumerated lists. 435 As an extra permitted piece of markup, @var will be turned 436 into ``var``. 437 """ 438 439 # Handle the "@var means ``var`` case 440 doctext = re.sub(r'@([\w-]+)', r'``\1``', doctext) 441 442 rstlist = ViewList() 443 for line in doctext.splitlines(): 444 # The reported line number will always be that of the start line 445 # of the doc comment, rather than the actual location of the error. 446 # Being more precise would require overhaul of the QAPIDoc class 447 # to track lines more exactly within all the sub-parts of the doc 448 # comment, as well as counting lines here. 449 rstlist.append(line, self._cur_doc.info.fname, 450 self._cur_doc.info.line) 451 # Append a blank line -- in some cases rST syntax errors get 452 # attributed to the line after one with actual text, and if there 453 # isn't anything in the ViewList corresponding to that then Sphinx 454 # 1.6's AutodocReporter will then misidentify the source/line location 455 # in the error message (usually attributing it to the top-level 456 # .rst file rather than the offending .json file). The extra blank 457 # line won't affect the rendered output. 458 rstlist.append("", self._cur_doc.info.fname, self._cur_doc.info.line) 459 self._sphinx_directive.do_parse(rstlist, node) 460 461 def get_document_nodes(self): 462 """Return the list of docutils nodes which make up the document""" 463 return self._top_node.children 464 465 466# Turn the black formatter on for the rest of the file. 467# fmt: on 468 469 470class QAPISchemaGenDepVisitor(QAPISchemaVisitor): 471 """A QAPI schema visitor which adds Sphinx dependencies each module 472 473 This class calls the Sphinx note_dependency() function to tell Sphinx 474 that the generated documentation output depends on the input 475 schema file associated with each module in the QAPI input. 476 """ 477 478 def __init__(self, env, qapidir): 479 self._env = env 480 self._qapidir = qapidir 481 482 def visit_module(self, name): 483 if name != "./builtin": 484 qapifile = self._qapidir + "/" + name 485 self._env.note_dependency(os.path.abspath(qapifile)) 486 super().visit_module(name) 487 488 489class NestedDirective(Directive): 490 def run(self): 491 raise NotImplementedError 492 493 def do_parse(self, rstlist, node): 494 """ 495 Parse rST source lines and add them to the specified node 496 497 Take the list of rST source lines rstlist, parse them as 498 rST, and add the resulting docutils nodes as children of node. 499 The nodes are parsed in a way that allows them to include 500 subheadings (titles) without confusing the rendering of 501 anything else. 502 """ 503 with switch_source_input(self.state, rstlist): 504 nested_parse_with_titles(self.state, rstlist, node) 505 506 507class QAPIDocDirective(NestedDirective): 508 """Extract documentation from the specified QAPI .json file""" 509 510 required_argument = 1 511 optional_arguments = 1 512 option_spec = {"qapifile": directives.unchanged_required} 513 has_content = False 514 515 def new_serialno(self): 516 """Return a unique new ID string suitable for use as a node's ID""" 517 env = self.state.document.settings.env 518 return "qapidoc-%d" % env.new_serialno("qapidoc") 519 520 def run(self): 521 env = self.state.document.settings.env 522 qapifile = env.config.qapidoc_srctree + "/" + self.arguments[0] 523 qapidir = os.path.dirname(qapifile) 524 525 try: 526 schema = QAPISchema(qapifile) 527 528 # First tell Sphinx about all the schema files that the 529 # output documentation depends on (including 'qapifile' itself) 530 schema.visit(QAPISchemaGenDepVisitor(env, qapidir)) 531 532 vis = QAPISchemaGenRSTVisitor(self) 533 vis.visit_begin(schema) 534 for doc in schema.docs: 535 if doc.symbol: 536 vis.symbol(doc, schema.lookup_entity(doc.symbol)) 537 else: 538 vis.freeform(doc) 539 return vis.get_document_nodes() 540 except QAPIError as err: 541 # Launder QAPI parse errors into Sphinx extension errors 542 # so they are displayed nicely to the user 543 raise ExtensionError(str(err)) from err 544 545 546class QMPExample(CodeBlock, NestedDirective): 547 """ 548 Custom admonition for QMP code examples. 549 550 When the :annotated: option is present, the body of this directive 551 is parsed as normal rST, but with any '::' code blocks set to use 552 the QMP lexer. Code blocks must be explicitly written by the user, 553 but this allows for intermingling explanatory paragraphs with 554 arbitrary rST syntax and code blocks for more involved examples. 555 556 When :annotated: is absent, the directive body is treated as a 557 simple standalone QMP code block literal. 558 """ 559 560 required_argument = 0 561 optional_arguments = 0 562 has_content = True 563 option_spec = { 564 "annotated": directives.flag, 565 "title": directives.unchanged, 566 } 567 568 def _highlightlang(self) -> addnodes.highlightlang: 569 """Return the current highlightlang setting for the document""" 570 node = None 571 doc = self.state.document 572 573 if hasattr(doc, "findall"): 574 # docutils >= 0.18.1 575 for node in doc.findall(addnodes.highlightlang): 576 pass 577 else: 578 for elem in doc.traverse(): 579 if isinstance(elem, addnodes.highlightlang): 580 node = elem 581 582 if node: 583 return node 584 585 # No explicit directive found, use defaults 586 node = addnodes.highlightlang( 587 lang=self.env.config.highlight_language, 588 force=False, 589 # Yes, Sphinx uses this value to effectively disable line 590 # numbers and not 0 or None or -1 or something. ¯\_(ツ)_/¯ 591 linenothreshold=sys.maxsize, 592 ) 593 return node 594 595 def admonition_wrap(self, *content) -> List[nodes.Node]: 596 title = "Example:" 597 if "title" in self.options: 598 title = f"{title} {self.options['title']}" 599 600 admon = nodes.admonition( 601 "", 602 nodes.title("", title), 603 *content, 604 classes=["admonition", "admonition-example"], 605 ) 606 return [admon] 607 608 def run_annotated(self) -> List[nodes.Node]: 609 lang_node = self._highlightlang() 610 611 content_node: nodes.Element = nodes.section() 612 613 # Configure QMP highlighting for "::" blocks, if needed 614 if lang_node["lang"] != "QMP": 615 content_node += addnodes.highlightlang( 616 lang="QMP", 617 force=False, # "True" ignores lexing errors 618 linenothreshold=lang_node["linenothreshold"], 619 ) 620 621 self.do_parse(self.content, content_node) 622 623 # Restore prior language highlighting, if needed 624 if lang_node["lang"] != "QMP": 625 content_node += addnodes.highlightlang(**lang_node.attributes) 626 627 return content_node.children 628 629 def run(self) -> List[nodes.Node]: 630 annotated = "annotated" in self.options 631 632 if annotated: 633 content_nodes = self.run_annotated() 634 else: 635 self.arguments = ["QMP"] 636 content_nodes = super().run() 637 638 return self.admonition_wrap(*content_nodes) 639 640 641def setup(app): 642 """Register qapi-doc directive with Sphinx""" 643 app.add_config_value("qapidoc_srctree", None, "env") 644 app.add_directive("qapi-doc", QAPIDocDirective) 645 app.add_directive("qmp-example", QMPExample) 646 647 return { 648 "version": __version__, 649 "parallel_read_safe": True, 650 "parallel_write_safe": True, 651 } 652