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 29 30from docutils import nodes 31from docutils.statemachine import ViewList 32from docutils.parsers.rst import directives, Directive 33from sphinx.errors import ExtensionError 34from sphinx.util.nodes import nested_parse_with_titles 35import sphinx 36from qapi.gen import QAPISchemaVisitor 37from qapi.error import QAPIError, QAPISemError 38from qapi.schema import QAPISchema 39 40 41# Sphinx up to 1.6 uses AutodocReporter; 1.7 and later 42# use switch_source_input. Check borrowed from kerneldoc.py. 43Use_SSI = sphinx.__version__[:3] >= '1.7' 44if Use_SSI: 45 from sphinx.util.docutils import switch_source_input 46else: 47 from sphinx.ext.autodoc import AutodocReporter 48 49 50__version__ = '1.0' 51 52 53# Function borrowed from pydash, which is under the MIT license 54def intersperse(iterable, separator): 55 """Yield the members of *iterable* interspersed with *separator*.""" 56 iterable = iter(iterable) 57 yield next(iterable) 58 for item in iterable: 59 yield separator 60 yield item 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, variants, 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 'variants' part of a definition list. 154 """ 155 term = [nodes.Text(' when '), 156 nodes.literal('', variants.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, variants=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 = section.text 171 elif (variants and variants.tag_member == section.member 172 and not section.member.type.doc_type()): 173 values = section.member.type.member_names() 174 defn = [nodes.Text('One of ')] 175 defn.extend(intersperse([nodes.literal('', v) for v in values], 176 nodes.Text(', '))) 177 else: 178 defn = [nodes.Text('Not documented')] 179 180 dlnode += self._make_dlitem(term, defn) 181 182 if base: 183 dlnode += self._make_dlitem([nodes.Text('The members of '), 184 nodes.literal('', base.doc_type())], 185 None) 186 187 if variants: 188 for v in variants.variants: 189 if v.type.is_implicit(): 190 assert not v.type.base and not v.type.variants 191 for m in v.type.local_members: 192 term = self._nodes_for_one_member(m) 193 term.extend(self._nodes_for_variant_when(variants, v)) 194 dlnode += self._make_dlitem(term, None) 195 else: 196 term = [nodes.Text('The members of '), 197 nodes.literal('', v.type.doc_type())] 198 term.extend(self._nodes_for_variant_when(variants, v)) 199 dlnode += self._make_dlitem(term, None) 200 201 if not dlnode.children: 202 return [] 203 204 section = self._make_section(what) 205 section += dlnode 206 return [section] 207 208 def _nodes_for_enum_values(self, doc): 209 """Return list of doctree nodes for the table of enum values""" 210 seen_item = False 211 dlnode = nodes.definition_list() 212 for section in doc.args.values(): 213 termtext = [nodes.literal('', section.member.name)] 214 if section.member.ifcond.is_present(): 215 termtext.extend(self._nodes_for_ifcond(section.member.ifcond)) 216 # TODO drop fallbacks when undocumented members are outlawed 217 if section.text: 218 defn = section.text 219 else: 220 defn = [nodes.Text('Not documented')] 221 222 dlnode += self._make_dlitem(termtext, defn) 223 seen_item = True 224 225 if not seen_item: 226 return [] 227 228 section = self._make_section('Values') 229 section += dlnode 230 return [section] 231 232 def _nodes_for_arguments(self, doc, boxed_arg_type): 233 """Return list of doctree nodes for the arguments section""" 234 if boxed_arg_type: 235 assert not doc.args 236 section = self._make_section('Arguments') 237 dlnode = nodes.definition_list() 238 dlnode += self._make_dlitem( 239 [nodes.Text('The members of '), 240 nodes.literal('', boxed_arg_type.name)], 241 None) 242 section += dlnode 243 return [section] 244 245 return self._nodes_for_members(doc, 'Arguments') 246 247 def _nodes_for_features(self, doc): 248 """Return list of doctree nodes for the table of features""" 249 seen_item = False 250 dlnode = nodes.definition_list() 251 for section in doc.features.values(): 252 dlnode += self._make_dlitem([nodes.literal('', section.name)], 253 section.text) 254 seen_item = True 255 256 if not seen_item: 257 return [] 258 259 section = self._make_section('Features') 260 section += dlnode 261 return [section] 262 263 def _nodes_for_example(self, exampletext): 264 """Return list of doctree nodes for a code example snippet""" 265 return [nodes.literal_block(exampletext, exampletext)] 266 267 def _nodes_for_sections(self, doc): 268 """Return list of doctree nodes for additional sections""" 269 nodelist = [] 270 for section in doc.sections: 271 if section.name and section.name == 'TODO': 272 # Hide TODO: sections 273 continue 274 snode = self._make_section(section.name) 275 if section.name and section.name.startswith('Example'): 276 snode += self._nodes_for_example(section.text) 277 else: 278 self._parse_text_into_node(section.text, snode) 279 nodelist.append(snode) 280 return nodelist 281 282 def _nodes_for_if_section(self, ifcond): 283 """Return list of doctree nodes for the "If" section""" 284 nodelist = [] 285 if ifcond.is_present(): 286 snode = self._make_section('If') 287 snode += nodes.paragraph( 288 '', '', *self._nodes_for_ifcond(ifcond, with_if=False) 289 ) 290 nodelist.append(snode) 291 return nodelist 292 293 def _add_doc(self, typ, sections): 294 """Add documentation for a command/object/enum... 295 296 We assume we're documenting the thing defined in self._cur_doc. 297 typ is the type of thing being added ("Command", "Object", etc) 298 299 sections is a list of nodes for sections to add to the definition. 300 """ 301 302 doc = self._cur_doc 303 snode = nodes.section(ids=[self._sphinx_directive.new_serialno()]) 304 snode += nodes.title('', '', *[nodes.literal(doc.symbol, doc.symbol), 305 nodes.Text(' (' + typ + ')')]) 306 self._parse_text_into_node(doc.body.text, snode) 307 for s in sections: 308 if s is not None: 309 snode += s 310 self._add_node_to_current_heading(snode) 311 312 def visit_enum_type(self, name, info, ifcond, features, members, prefix): 313 doc = self._cur_doc 314 self._add_doc('Enum', 315 self._nodes_for_enum_values(doc) 316 + self._nodes_for_features(doc) 317 + self._nodes_for_sections(doc) 318 + self._nodes_for_if_section(ifcond)) 319 320 def visit_object_type(self, name, info, ifcond, features, 321 base, members, variants): 322 doc = self._cur_doc 323 if base and base.is_implicit(): 324 base = None 325 self._add_doc('Object', 326 self._nodes_for_members(doc, 'Members', base, variants) 327 + self._nodes_for_features(doc) 328 + self._nodes_for_sections(doc) 329 + self._nodes_for_if_section(ifcond)) 330 331 def visit_alternate_type(self, name, info, ifcond, features, variants): 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, 345 arg_type if boxed else None) 346 + self._nodes_for_features(doc) 347 + self._nodes_for_sections(doc) 348 + self._nodes_for_if_section(ifcond)) 349 350 def visit_event(self, name, info, ifcond, features, arg_type, boxed): 351 doc = self._cur_doc 352 self._add_doc('Event', 353 self._nodes_for_arguments(doc, 354 arg_type if boxed else None) 355 + self._nodes_for_features(doc) 356 + self._nodes_for_sections(doc) 357 + self._nodes_for_if_section(ifcond)) 358 359 def symbol(self, doc, entity): 360 """Add documentation for one symbol to the document tree 361 362 This is the main entry point which causes us to add documentation 363 nodes for a symbol (which could be a 'command', 'object', 'event', 364 etc). We do this by calling 'visit' on the schema entity, which 365 will then call back into one of our visit_* methods, depending 366 on what kind of thing this symbol is. 367 """ 368 self._cur_doc = doc 369 entity.visit(self) 370 self._cur_doc = None 371 372 def _start_new_heading(self, heading, level): 373 """Start a new heading at the specified heading level 374 375 Create a new section whose title is 'heading' and which is placed 376 in the docutils node tree as a child of the most recent level-1 377 heading. Subsequent document sections (commands, freeform doc chunks, 378 etc) will be placed as children of this new heading section. 379 """ 380 if len(self._active_headings) < level: 381 raise QAPISemError(self._cur_doc.info, 382 'Level %d subheading found outside a ' 383 'level %d heading' 384 % (level, level - 1)) 385 snode = self._make_section(heading) 386 self._active_headings[level - 1] += snode 387 self._active_headings = self._active_headings[:level] 388 self._active_headings.append(snode) 389 390 def _add_node_to_current_heading(self, node): 391 """Add the node to whatever the current active heading is""" 392 self._active_headings[-1] += node 393 394 def freeform(self, doc): 395 """Add a piece of 'freeform' documentation to the document tree 396 397 A 'freeform' document chunk doesn't relate to any particular 398 symbol (for instance, it could be an introduction). 399 400 If the freeform document starts with a line of the form 401 '= Heading text', this is a section or subsection heading, with 402 the heading level indicated by the number of '=' signs. 403 """ 404 405 # QAPIDoc documentation says free-form documentation blocks 406 # must have only a body section, nothing else. 407 assert not doc.sections 408 assert not doc.args 409 assert not doc.features 410 self._cur_doc = doc 411 412 text = doc.body.text 413 if re.match(r'=+ ', text): 414 # Section/subsection heading (if present, will always be 415 # the first line of the block) 416 (heading, _, text) = text.partition('\n') 417 (leader, _, heading) = heading.partition(' ') 418 self._start_new_heading(heading, len(leader)) 419 if text == '': 420 return 421 422 node = self._make_section(None) 423 self._parse_text_into_node(text, node) 424 self._add_node_to_current_heading(node) 425 self._cur_doc = None 426 427 def _parse_text_into_node(self, doctext, node): 428 """Parse a chunk of QAPI-doc-format text into the node 429 430 The doc comment can contain most inline rST markup, including 431 bulleted and enumerated lists. 432 As an extra permitted piece of markup, @var will be turned 433 into ``var``. 434 """ 435 436 # Handle the "@var means ``var`` case 437 doctext = re.sub(r'@([\w-]+)', r'``\1``', doctext) 438 439 rstlist = ViewList() 440 for line in doctext.splitlines(): 441 # The reported line number will always be that of the start line 442 # of the doc comment, rather than the actual location of the error. 443 # Being more precise would require overhaul of the QAPIDoc class 444 # to track lines more exactly within all the sub-parts of the doc 445 # comment, as well as counting lines here. 446 rstlist.append(line, self._cur_doc.info.fname, 447 self._cur_doc.info.line) 448 # Append a blank line -- in some cases rST syntax errors get 449 # attributed to the line after one with actual text, and if there 450 # isn't anything in the ViewList corresponding to that then Sphinx 451 # 1.6's AutodocReporter will then misidentify the source/line location 452 # in the error message (usually attributing it to the top-level 453 # .rst file rather than the offending .json file). The extra blank 454 # line won't affect the rendered output. 455 rstlist.append("", self._cur_doc.info.fname, self._cur_doc.info.line) 456 self._sphinx_directive.do_parse(rstlist, node) 457 458 def get_document_nodes(self): 459 """Return the list of docutils nodes which make up the document""" 460 return self._top_node.children 461 462 463class QAPISchemaGenDepVisitor(QAPISchemaVisitor): 464 """A QAPI schema visitor which adds Sphinx dependencies each module 465 466 This class calls the Sphinx note_dependency() function to tell Sphinx 467 that the generated documentation output depends on the input 468 schema file associated with each module in the QAPI input. 469 """ 470 def __init__(self, env, qapidir): 471 self._env = env 472 self._qapidir = qapidir 473 474 def visit_module(self, name): 475 if name != "./builtin": 476 qapifile = self._qapidir + '/' + name 477 self._env.note_dependency(os.path.abspath(qapifile)) 478 super().visit_module(name) 479 480 481class QAPIDocDirective(Directive): 482 """Extract documentation from the specified QAPI .json file""" 483 required_argument = 1 484 optional_arguments = 1 485 option_spec = { 486 'qapifile': directives.unchanged_required 487 } 488 has_content = False 489 490 def new_serialno(self): 491 """Return a unique new ID string suitable for use as a node's ID""" 492 env = self.state.document.settings.env 493 return 'qapidoc-%d' % env.new_serialno('qapidoc') 494 495 def run(self): 496 env = self.state.document.settings.env 497 qapifile = env.config.qapidoc_srctree + '/' + self.arguments[0] 498 qapidir = os.path.dirname(qapifile) 499 500 try: 501 schema = QAPISchema(qapifile) 502 503 # First tell Sphinx about all the schema files that the 504 # output documentation depends on (including 'qapifile' itself) 505 schema.visit(QAPISchemaGenDepVisitor(env, qapidir)) 506 507 vis = QAPISchemaGenRSTVisitor(self) 508 vis.visit_begin(schema) 509 for doc in schema.docs: 510 if doc.symbol: 511 vis.symbol(doc, schema.lookup_entity(doc.symbol)) 512 else: 513 vis.freeform(doc) 514 return vis.get_document_nodes() 515 except QAPIError as err: 516 # Launder QAPI parse errors into Sphinx extension errors 517 # so they are displayed nicely to the user 518 raise ExtensionError(str(err)) from err 519 520 def do_parse(self, rstlist, node): 521 """Parse rST source lines and add them to the specified node 522 523 Take the list of rST source lines rstlist, parse them as 524 rST, and add the resulting docutils nodes as children of node. 525 The nodes are parsed in a way that allows them to include 526 subheadings (titles) without confusing the rendering of 527 anything else. 528 """ 529 # This is from kerneldoc.py -- it works around an API change in 530 # Sphinx between 1.6 and 1.7. Unlike kerneldoc.py, we use 531 # sphinx.util.nodes.nested_parse_with_titles() rather than the 532 # plain self.state.nested_parse(), and so we can drop the saving 533 # of title_styles and section_level that kerneldoc.py does, 534 # because nested_parse_with_titles() does that for us. 535 if Use_SSI: 536 with switch_source_input(self.state, rstlist): 537 nested_parse_with_titles(self.state, rstlist, node) 538 else: 539 save = self.state.memo.reporter 540 self.state.memo.reporter = AutodocReporter( 541 rstlist, self.state.memo.reporter) 542 try: 543 nested_parse_with_titles(self.state, rstlist, node) 544 finally: 545 self.state.memo.reporter = save 546 547 548def setup(app): 549 """ Register qapi-doc directive with Sphinx""" 550 app.add_config_value('qapidoc_srctree', None, 'env') 551 app.add_directive('qapi-doc', QAPIDocDirective) 552 553 return dict( 554 version=__version__, 555 parallel_read_safe=True, 556 parallel_write_safe=True 557 ) 558