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.schema import QAPIError, QAPISemError, QAPISchema 38 39 40# Sphinx up to 1.6 uses AutodocReporter; 1.7 and later 41# use switch_source_input. Check borrowed from kerneldoc.py. 42Use_SSI = sphinx.__version__[:3] >= '1.7' 43if Use_SSI: 44 from sphinx.util.docutils import switch_source_input 45else: 46 from sphinx.ext.autodoc import AutodocReporter 47 48 49__version__ = '1.0' 50 51 52# Function borrowed from pydash, which is under the MIT license 53def intersperse(iterable, separator): 54 """Yield the members of *iterable* interspersed with *separator*.""" 55 iterable = iter(iterable) 56 yield next(iterable) 57 for item in iterable: 58 yield separator 59 yield item 60 61 62class QAPISchemaGenRSTVisitor(QAPISchemaVisitor): 63 """A QAPI schema visitor which generates docutils/Sphinx nodes 64 65 This class builds up a tree of docutils/Sphinx nodes corresponding 66 to documentation for the various QAPI objects. To use it, first 67 create a QAPISchemaGenRSTVisitor object, and call its 68 visit_begin() method. Then you can call one of the two methods 69 'freeform' (to add documentation for a freeform documentation 70 chunk) or 'symbol' (to add documentation for a QAPI symbol). These 71 will cause the visitor to build up the tree of document 72 nodes. Once you've added all the documentation via 'freeform' and 73 'symbol' method calls, you can call 'get_document_nodes' to get 74 the final list of document nodes (in a form suitable for returning 75 from a Sphinx directive's 'run' method). 76 """ 77 def __init__(self, sphinx_directive): 78 self._cur_doc = None 79 self._sphinx_directive = sphinx_directive 80 self._top_node = nodes.section() 81 self._active_headings = [self._top_node] 82 83 def _make_dlitem(self, term, defn): 84 """Return a dlitem node with the specified term and definition. 85 86 term should be a list of Text and literal nodes. 87 defn should be one of: 88 - a string, which will be handed to _parse_text_into_node 89 - a list of Text and literal nodes, which will be put into 90 a paragraph node 91 """ 92 dlitem = nodes.definition_list_item() 93 dlterm = nodes.term('', '', *term) 94 dlitem += dlterm 95 if defn: 96 dldef = nodes.definition() 97 if isinstance(defn, list): 98 dldef += nodes.paragraph('', '', *defn) 99 else: 100 self._parse_text_into_node(defn, dldef) 101 dlitem += dldef 102 return dlitem 103 104 def _make_section(self, title): 105 """Return a section node with optional title""" 106 section = nodes.section(ids=[self._sphinx_directive.new_serialno()]) 107 if title: 108 section += nodes.title(title, title) 109 return section 110 111 def _nodes_for_ifcond(self, ifcond, with_if=True): 112 """Return list of Text, literal nodes for the ifcond 113 114 Return a list which gives text like ' (If: cond1, cond2, cond3)', where 115 the conditions are in literal-text and the commas are not. 116 If with_if is False, we don't return the "(If: " and ")". 117 """ 118 condlist = intersperse([nodes.literal('', c) for c in ifcond], 119 nodes.Text(', ')) 120 if not with_if: 121 return condlist 122 123 nodelist = [nodes.Text(' ('), nodes.strong('', 'If: ')] 124 nodelist.extend(condlist) 125 nodelist.append(nodes.Text(')')) 126 return nodelist 127 128 def _nodes_for_one_member(self, member): 129 """Return list of Text, literal nodes for this member 130 131 Return a list of doctree nodes which give text like 132 'name: type (optional) (If: ...)' suitable for use as the 133 'term' part of a definition list item. 134 """ 135 term = [nodes.literal('', member.name)] 136 if member.type.doc_type(): 137 term.append(nodes.Text(': ')) 138 term.append(nodes.literal('', member.type.doc_type())) 139 if member.optional: 140 term.append(nodes.Text(' (optional)')) 141 if member.ifcond: 142 term.extend(self._nodes_for_ifcond(member.ifcond)) 143 return term 144 145 def _nodes_for_variant_when(self, variants, variant): 146 """Return list of Text, literal nodes for variant 'when' clause 147 148 Return a list of doctree nodes which give text like 149 'when tagname is variant (If: ...)' suitable for use in 150 the 'variants' part of a definition list. 151 """ 152 term = [nodes.Text(' when '), 153 nodes.literal('', variants.tag_member.name), 154 nodes.Text(' is '), 155 nodes.literal('', '"%s"' % variant.name)] 156 if variant.ifcond: 157 term.extend(self._nodes_for_ifcond(variant.ifcond)) 158 return term 159 160 def _nodes_for_members(self, doc, what, base=None, variants=None): 161 """Return list of doctree nodes for the table of members""" 162 dlnode = nodes.definition_list() 163 for section in doc.args.values(): 164 term = self._nodes_for_one_member(section.member) 165 # TODO drop fallbacks when undocumented members are outlawed 166 if section.text: 167 defn = section.text 168 elif (variants and variants.tag_member == section.member 169 and not section.member.type.doc_type()): 170 values = section.member.type.member_names() 171 defn = [nodes.Text('One of ')] 172 defn.extend(intersperse([nodes.literal('', v) for v in values], 173 nodes.Text(', '))) 174 else: 175 defn = [nodes.Text('Not documented')] 176 177 dlnode += self._make_dlitem(term, defn) 178 179 if base: 180 dlnode += self._make_dlitem([nodes.Text('The members of '), 181 nodes.literal('', base.doc_type())], 182 None) 183 184 if variants: 185 for v in variants.variants: 186 if v.type.is_implicit(): 187 assert not v.type.base and not v.type.variants 188 for m in v.type.local_members: 189 term = self._nodes_for_one_member(m) 190 term.extend(self._nodes_for_variant_when(variants, v)) 191 dlnode += self._make_dlitem(term, None) 192 else: 193 term = [nodes.Text('The members of '), 194 nodes.literal('', v.type.doc_type())] 195 term.extend(self._nodes_for_variant_when(variants, v)) 196 dlnode += self._make_dlitem(term, None) 197 198 if not dlnode.children: 199 return [] 200 201 section = self._make_section(what) 202 section += dlnode 203 return [section] 204 205 def _nodes_for_enum_values(self, doc): 206 """Return list of doctree nodes for the table of enum values""" 207 seen_item = False 208 dlnode = nodes.definition_list() 209 for section in doc.args.values(): 210 termtext = [nodes.literal('', section.member.name)] 211 if section.member.ifcond: 212 termtext.extend(self._nodes_for_ifcond(section.member.ifcond)) 213 # TODO drop fallbacks when undocumented members are outlawed 214 if section.text: 215 defn = section.text 216 else: 217 defn = [nodes.Text('Not documented')] 218 219 dlnode += self._make_dlitem(termtext, defn) 220 seen_item = True 221 222 if not seen_item: 223 return [] 224 225 section = self._make_section('Values') 226 section += dlnode 227 return [section] 228 229 def _nodes_for_arguments(self, doc, boxed_arg_type): 230 """Return list of doctree nodes for the arguments section""" 231 if boxed_arg_type: 232 assert not doc.args 233 section = self._make_section('Arguments') 234 dlnode = nodes.definition_list() 235 dlnode += self._make_dlitem( 236 [nodes.Text('The members of '), 237 nodes.literal('', boxed_arg_type.name)], 238 None) 239 section += dlnode 240 return [section] 241 242 return self._nodes_for_members(doc, 'Arguments') 243 244 def _nodes_for_features(self, doc): 245 """Return list of doctree nodes for the table of features""" 246 seen_item = False 247 dlnode = nodes.definition_list() 248 for section in doc.features.values(): 249 dlnode += self._make_dlitem([nodes.literal('', section.name)], 250 section.text) 251 seen_item = True 252 253 if not seen_item: 254 return [] 255 256 section = self._make_section('Features') 257 section += dlnode 258 return [section] 259 260 def _nodes_for_example(self, exampletext): 261 """Return list of doctree nodes for a code example snippet""" 262 return [nodes.literal_block(exampletext, exampletext)] 263 264 def _nodes_for_sections(self, doc): 265 """Return list of doctree nodes for additional sections""" 266 nodelist = [] 267 for section in doc.sections: 268 snode = self._make_section(section.name) 269 if section.name and section.name.startswith('Example'): 270 snode += self._nodes_for_example(section.text) 271 else: 272 self._parse_text_into_node(section.text, snode) 273 nodelist.append(snode) 274 return nodelist 275 276 def _nodes_for_if_section(self, ifcond): 277 """Return list of doctree nodes for the "If" section""" 278 nodelist = [] 279 if ifcond: 280 snode = self._make_section('If') 281 snode += self._nodes_for_ifcond(ifcond, with_if=False) 282 nodelist.append(snode) 283 return nodelist 284 285 def _add_doc(self, typ, sections): 286 """Add documentation for a command/object/enum... 287 288 We assume we're documenting the thing defined in self._cur_doc. 289 typ is the type of thing being added ("Command", "Object", etc) 290 291 sections is a list of nodes for sections to add to the definition. 292 """ 293 294 doc = self._cur_doc 295 snode = nodes.section(ids=[self._sphinx_directive.new_serialno()]) 296 snode += nodes.title('', '', *[nodes.literal(doc.symbol, doc.symbol), 297 nodes.Text(' (' + typ + ')')]) 298 self._parse_text_into_node(doc.body.text, snode) 299 for s in sections: 300 if s is not None: 301 snode += s 302 self._add_node_to_current_heading(snode) 303 304 def visit_enum_type(self, name, info, ifcond, features, members, prefix): 305 doc = self._cur_doc 306 self._add_doc('Enum', 307 self._nodes_for_enum_values(doc) 308 + self._nodes_for_features(doc) 309 + self._nodes_for_sections(doc) 310 + self._nodes_for_if_section(ifcond)) 311 312 def visit_object_type(self, name, info, ifcond, features, 313 base, members, variants): 314 doc = self._cur_doc 315 if base and base.is_implicit(): 316 base = None 317 self._add_doc('Object', 318 self._nodes_for_members(doc, 'Members', base, variants) 319 + self._nodes_for_features(doc) 320 + self._nodes_for_sections(doc) 321 + self._nodes_for_if_section(ifcond)) 322 323 def visit_alternate_type(self, name, info, ifcond, features, variants): 324 doc = self._cur_doc 325 self._add_doc('Alternate', 326 self._nodes_for_members(doc, 'Members') 327 + self._nodes_for_features(doc) 328 + self._nodes_for_sections(doc) 329 + self._nodes_for_if_section(ifcond)) 330 331 def visit_command(self, name, info, ifcond, features, arg_type, 332 ret_type, gen, success_response, boxed, allow_oob, 333 allow_preconfig, coroutine): 334 doc = self._cur_doc 335 self._add_doc('Command', 336 self._nodes_for_arguments(doc, 337 arg_type if boxed else None) 338 + self._nodes_for_features(doc) 339 + self._nodes_for_sections(doc) 340 + self._nodes_for_if_section(ifcond)) 341 342 def visit_event(self, name, info, ifcond, features, arg_type, boxed): 343 doc = self._cur_doc 344 self._add_doc('Event', 345 self._nodes_for_arguments(doc, 346 arg_type if boxed else None) 347 + self._nodes_for_features(doc) 348 + self._nodes_for_sections(doc) 349 + self._nodes_for_if_section(ifcond)) 350 351 def symbol(self, doc, entity): 352 """Add documentation for one symbol to the document tree 353 354 This is the main entry point which causes us to add documentation 355 nodes for a symbol (which could be a 'command', 'object', 'event', 356 etc). We do this by calling 'visit' on the schema entity, which 357 will then call back into one of our visit_* methods, depending 358 on what kind of thing this symbol is. 359 """ 360 self._cur_doc = doc 361 entity.visit(self) 362 self._cur_doc = None 363 364 def _start_new_heading(self, heading, level): 365 """Start a new heading at the specified heading level 366 367 Create a new section whose title is 'heading' and which is placed 368 in the docutils node tree as a child of the most recent level-1 369 heading. Subsequent document sections (commands, freeform doc chunks, 370 etc) will be placed as children of this new heading section. 371 """ 372 if len(self._active_headings) < level: 373 raise QAPISemError(self._cur_doc.info, 374 'Level %d subheading found outside a ' 375 'level %d heading' 376 % (level, level - 1)) 377 snode = self._make_section(heading) 378 self._active_headings[level - 1] += snode 379 self._active_headings = self._active_headings[:level] 380 self._active_headings.append(snode) 381 382 def _add_node_to_current_heading(self, node): 383 """Add the node to whatever the current active heading is""" 384 self._active_headings[-1] += node 385 386 def freeform(self, doc): 387 """Add a piece of 'freeform' documentation to the document tree 388 389 A 'freeform' document chunk doesn't relate to any particular 390 symbol (for instance, it could be an introduction). 391 392 If the freeform document starts with a line of the form 393 '= Heading text', this is a section or subsection heading, with 394 the heading level indicated by the number of '=' signs. 395 """ 396 397 # QAPIDoc documentation says free-form documentation blocks 398 # must have only a body section, nothing else. 399 assert not doc.sections 400 assert not doc.args 401 assert not doc.features 402 self._cur_doc = doc 403 404 text = doc.body.text 405 if re.match(r'=+ ', text): 406 # Section/subsection heading (if present, will always be 407 # the first line of the block) 408 (heading, _, text) = text.partition('\n') 409 (leader, _, heading) = heading.partition(' ') 410 self._start_new_heading(heading, len(leader)) 411 if text == '': 412 return 413 414 node = self._make_section(None) 415 self._parse_text_into_node(text, node) 416 self._add_node_to_current_heading(node) 417 self._cur_doc = None 418 419 def _parse_text_into_node(self, doctext, node): 420 """Parse a chunk of QAPI-doc-format text into the node 421 422 The doc comment can contain most inline rST markup, including 423 bulleted and enumerated lists. 424 As an extra permitted piece of markup, @var will be turned 425 into ``var``. 426 """ 427 428 # Handle the "@var means ``var`` case 429 doctext = re.sub(r'@([\w-]+)', r'``\1``', doctext) 430 431 rstlist = ViewList() 432 for line in doctext.splitlines(): 433 # The reported line number will always be that of the start line 434 # of the doc comment, rather than the actual location of the error. 435 # Being more precise would require overhaul of the QAPIDoc class 436 # to track lines more exactly within all the sub-parts of the doc 437 # comment, as well as counting lines here. 438 rstlist.append(line, self._cur_doc.info.fname, 439 self._cur_doc.info.line) 440 # Append a blank line -- in some cases rST syntax errors get 441 # attributed to the line after one with actual text, and if there 442 # isn't anything in the ViewList corresponding to that then Sphinx 443 # 1.6's AutodocReporter will then misidentify the source/line location 444 # in the error message (usually attributing it to the top-level 445 # .rst file rather than the offending .json file). The extra blank 446 # line won't affect the rendered output. 447 rstlist.append("", self._cur_doc.info.fname, self._cur_doc.info.line) 448 self._sphinx_directive.do_parse(rstlist, node) 449 450 def get_document_nodes(self): 451 """Return the list of docutils nodes which make up the document""" 452 return self._top_node.children 453 454 455class QAPISchemaGenDepVisitor(QAPISchemaVisitor): 456 """A QAPI schema visitor which adds Sphinx dependencies each module 457 458 This class calls the Sphinx note_dependency() function to tell Sphinx 459 that the generated documentation output depends on the input 460 schema file associated with each module in the QAPI input. 461 """ 462 def __init__(self, env, qapidir): 463 self._env = env 464 self._qapidir = qapidir 465 466 def visit_module(self, name): 467 if name != "./builtin": 468 qapifile = self._qapidir + '/' + name 469 self._env.note_dependency(os.path.abspath(qapifile)) 470 super().visit_module(name) 471 472 473class QAPIDocDirective(Directive): 474 """Extract documentation from the specified QAPI .json file""" 475 required_argument = 1 476 optional_arguments = 1 477 option_spec = { 478 'qapifile': directives.unchanged_required 479 } 480 has_content = False 481 482 def new_serialno(self): 483 """Return a unique new ID string suitable for use as a node's ID""" 484 env = self.state.document.settings.env 485 return 'qapidoc-%d' % env.new_serialno('qapidoc') 486 487 def run(self): 488 env = self.state.document.settings.env 489 qapifile = env.config.qapidoc_srctree + '/' + self.arguments[0] 490 qapidir = os.path.dirname(qapifile) 491 492 try: 493 schema = QAPISchema(qapifile) 494 495 # First tell Sphinx about all the schema files that the 496 # output documentation depends on (including 'qapifile' itself) 497 schema.visit(QAPISchemaGenDepVisitor(env, qapidir)) 498 499 vis = QAPISchemaGenRSTVisitor(self) 500 vis.visit_begin(schema) 501 for doc in schema.docs: 502 if doc.symbol: 503 vis.symbol(doc, schema.lookup_entity(doc.symbol)) 504 else: 505 vis.freeform(doc) 506 return vis.get_document_nodes() 507 except QAPIError as err: 508 # Launder QAPI parse errors into Sphinx extension errors 509 # so they are displayed nicely to the user 510 raise ExtensionError(str(err)) 511 512 def do_parse(self, rstlist, node): 513 """Parse rST source lines and add them to the specified node 514 515 Take the list of rST source lines rstlist, parse them as 516 rST, and add the resulting docutils nodes as children of node. 517 The nodes are parsed in a way that allows them to include 518 subheadings (titles) without confusing the rendering of 519 anything else. 520 """ 521 # This is from kerneldoc.py -- it works around an API change in 522 # Sphinx between 1.6 and 1.7. Unlike kerneldoc.py, we use 523 # sphinx.util.nodes.nested_parse_with_titles() rather than the 524 # plain self.state.nested_parse(), and so we can drop the saving 525 # of title_styles and section_level that kerneldoc.py does, 526 # because nested_parse_with_titles() does that for us. 527 if Use_SSI: 528 with switch_source_input(self.state, rstlist): 529 nested_parse_with_titles(self.state, rstlist, node) 530 else: 531 save = self.state.memo.reporter 532 self.state.memo.reporter = AutodocReporter( 533 rstlist, self.state.memo.reporter) 534 try: 535 nested_parse_with_titles(self.state, rstlist, node) 536 finally: 537 self.state.memo.reporter = save 538 539 540def setup(app): 541 """ Register qapi-doc directive with Sphinx""" 542 app.add_config_value('qapidoc_srctree', None, 'env') 543 app.add_directive('qapi-doc', QAPIDocDirective) 544 545 return dict( 546 version=__version__, 547 parallel_read_safe=True, 548 parallel_write_safe=True 549 ) 550