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 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 variants: 182 for v in variants.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(variants, 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 = 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, boxed_arg_type): 223 """Return list of doctree nodes for the arguments section""" 224 if boxed_arg_type: 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('', boxed_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)], 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 snode = self._make_section(section.tag) 265 if section.tag and section.tag.startswith('Example'): 266 snode += self._nodes_for_example(section.text) 267 else: 268 self._parse_text_into_node(section.text, snode) 269 nodelist.append(snode) 270 return nodelist 271 272 def _nodes_for_if_section(self, ifcond): 273 """Return list of doctree nodes for the "If" section""" 274 nodelist = [] 275 if ifcond.is_present(): 276 snode = self._make_section('If') 277 snode += nodes.paragraph( 278 '', '', *self._nodes_for_ifcond(ifcond, with_if=False) 279 ) 280 nodelist.append(snode) 281 return nodelist 282 283 def _add_doc(self, typ, sections): 284 """Add documentation for a command/object/enum... 285 286 We assume we're documenting the thing defined in self._cur_doc. 287 typ is the type of thing being added ("Command", "Object", etc) 288 289 sections is a list of nodes for sections to add to the definition. 290 """ 291 292 doc = self._cur_doc 293 snode = nodes.section(ids=[self._sphinx_directive.new_serialno()]) 294 snode += nodes.title('', '', *[nodes.literal(doc.symbol, doc.symbol), 295 nodes.Text(' (' + typ + ')')]) 296 self._parse_text_into_node(doc.body.text, snode) 297 for s in sections: 298 if s is not None: 299 snode += s 300 self._add_node_to_current_heading(snode) 301 302 def visit_enum_type(self, name, info, ifcond, features, members, prefix): 303 doc = self._cur_doc 304 self._add_doc('Enum', 305 self._nodes_for_enum_values(doc) 306 + self._nodes_for_features(doc) 307 + self._nodes_for_sections(doc) 308 + self._nodes_for_if_section(ifcond)) 309 310 def visit_object_type(self, name, info, ifcond, features, 311 base, members, variants): 312 doc = self._cur_doc 313 if base and base.is_implicit(): 314 base = None 315 self._add_doc('Object', 316 self._nodes_for_members(doc, 'Members', base, variants) 317 + self._nodes_for_features(doc) 318 + self._nodes_for_sections(doc) 319 + self._nodes_for_if_section(ifcond)) 320 321 def visit_alternate_type(self, name, info, ifcond, features, variants): 322 doc = self._cur_doc 323 self._add_doc('Alternate', 324 self._nodes_for_members(doc, 'Members') 325 + self._nodes_for_features(doc) 326 + self._nodes_for_sections(doc) 327 + self._nodes_for_if_section(ifcond)) 328 329 def visit_command(self, name, info, ifcond, features, arg_type, 330 ret_type, gen, success_response, boxed, allow_oob, 331 allow_preconfig, coroutine): 332 doc = self._cur_doc 333 self._add_doc('Command', 334 self._nodes_for_arguments(doc, 335 arg_type if boxed else None) 336 + self._nodes_for_features(doc) 337 + self._nodes_for_sections(doc) 338 + self._nodes_for_if_section(ifcond)) 339 340 def visit_event(self, name, info, ifcond, features, arg_type, boxed): 341 doc = self._cur_doc 342 self._add_doc('Event', 343 self._nodes_for_arguments(doc, 344 arg_type if boxed else None) 345 + self._nodes_for_features(doc) 346 + self._nodes_for_sections(doc) 347 + self._nodes_for_if_section(ifcond)) 348 349 def symbol(self, doc, entity): 350 """Add documentation for one symbol to the document tree 351 352 This is the main entry point which causes us to add documentation 353 nodes for a symbol (which could be a 'command', 'object', 'event', 354 etc). We do this by calling 'visit' on the schema entity, which 355 will then call back into one of our visit_* methods, depending 356 on what kind of thing this symbol is. 357 """ 358 self._cur_doc = doc 359 entity.visit(self) 360 self._cur_doc = None 361 362 def _start_new_heading(self, heading, level): 363 """Start a new heading at the specified heading level 364 365 Create a new section whose title is 'heading' and which is placed 366 in the docutils node tree as a child of the most recent level-1 367 heading. Subsequent document sections (commands, freeform doc chunks, 368 etc) will be placed as children of this new heading section. 369 """ 370 if len(self._active_headings) < level: 371 raise QAPISemError(self._cur_doc.info, 372 'Level %d subheading found outside a ' 373 'level %d heading' 374 % (level, level - 1)) 375 snode = self._make_section(heading) 376 self._active_headings[level - 1] += snode 377 self._active_headings = self._active_headings[:level] 378 self._active_headings.append(snode) 379 380 def _add_node_to_current_heading(self, node): 381 """Add the node to whatever the current active heading is""" 382 self._active_headings[-1] += node 383 384 def freeform(self, doc): 385 """Add a piece of 'freeform' documentation to the document tree 386 387 A 'freeform' document chunk doesn't relate to any particular 388 symbol (for instance, it could be an introduction). 389 390 If the freeform document starts with a line of the form 391 '= Heading text', this is a section or subsection heading, with 392 the heading level indicated by the number of '=' signs. 393 """ 394 395 # QAPIDoc documentation says free-form documentation blocks 396 # must have only a body section, nothing else. 397 assert not doc.sections 398 assert not doc.args 399 assert not doc.features 400 self._cur_doc = doc 401 402 text = doc.body.text 403 if re.match(r'=+ ', text): 404 # Section/subsection heading (if present, will always be 405 # the first line of the block) 406 (heading, _, text) = text.partition('\n') 407 (leader, _, heading) = heading.partition(' ') 408 self._start_new_heading(heading, len(leader)) 409 if text == '': 410 return 411 412 node = self._make_section(None) 413 self._parse_text_into_node(text, node) 414 self._add_node_to_current_heading(node) 415 self._cur_doc = None 416 417 def _parse_text_into_node(self, doctext, node): 418 """Parse a chunk of QAPI-doc-format text into the node 419 420 The doc comment can contain most inline rST markup, including 421 bulleted and enumerated lists. 422 As an extra permitted piece of markup, @var will be turned 423 into ``var``. 424 """ 425 426 # Handle the "@var means ``var`` case 427 doctext = re.sub(r'@([\w-]+)', r'``\1``', doctext) 428 429 rstlist = ViewList() 430 for line in doctext.splitlines(): 431 # The reported line number will always be that of the start line 432 # of the doc comment, rather than the actual location of the error. 433 # Being more precise would require overhaul of the QAPIDoc class 434 # to track lines more exactly within all the sub-parts of the doc 435 # comment, as well as counting lines here. 436 rstlist.append(line, self._cur_doc.info.fname, 437 self._cur_doc.info.line) 438 # Append a blank line -- in some cases rST syntax errors get 439 # attributed to the line after one with actual text, and if there 440 # isn't anything in the ViewList corresponding to that then Sphinx 441 # 1.6's AutodocReporter will then misidentify the source/line location 442 # in the error message (usually attributing it to the top-level 443 # .rst file rather than the offending .json file). The extra blank 444 # line won't affect the rendered output. 445 rstlist.append("", self._cur_doc.info.fname, self._cur_doc.info.line) 446 self._sphinx_directive.do_parse(rstlist, node) 447 448 def get_document_nodes(self): 449 """Return the list of docutils nodes which make up the document""" 450 return self._top_node.children 451 452 453class QAPISchemaGenDepVisitor(QAPISchemaVisitor): 454 """A QAPI schema visitor which adds Sphinx dependencies each module 455 456 This class calls the Sphinx note_dependency() function to tell Sphinx 457 that the generated documentation output depends on the input 458 schema file associated with each module in the QAPI input. 459 """ 460 def __init__(self, env, qapidir): 461 self._env = env 462 self._qapidir = qapidir 463 464 def visit_module(self, name): 465 if name != "./builtin": 466 qapifile = self._qapidir + '/' + name 467 self._env.note_dependency(os.path.abspath(qapifile)) 468 super().visit_module(name) 469 470 471class QAPIDocDirective(Directive): 472 """Extract documentation from the specified QAPI .json file""" 473 required_argument = 1 474 optional_arguments = 1 475 option_spec = { 476 'qapifile': directives.unchanged_required 477 } 478 has_content = False 479 480 def new_serialno(self): 481 """Return a unique new ID string suitable for use as a node's ID""" 482 env = self.state.document.settings.env 483 return 'qapidoc-%d' % env.new_serialno('qapidoc') 484 485 def run(self): 486 env = self.state.document.settings.env 487 qapifile = env.config.qapidoc_srctree + '/' + self.arguments[0] 488 qapidir = os.path.dirname(qapifile) 489 490 try: 491 schema = QAPISchema(qapifile) 492 493 # First tell Sphinx about all the schema files that the 494 # output documentation depends on (including 'qapifile' itself) 495 schema.visit(QAPISchemaGenDepVisitor(env, qapidir)) 496 497 vis = QAPISchemaGenRSTVisitor(self) 498 vis.visit_begin(schema) 499 for doc in schema.docs: 500 if doc.symbol: 501 vis.symbol(doc, schema.lookup_entity(doc.symbol)) 502 else: 503 vis.freeform(doc) 504 return vis.get_document_nodes() 505 except QAPIError as err: 506 # Launder QAPI parse errors into Sphinx extension errors 507 # so they are displayed nicely to the user 508 raise ExtensionError(str(err)) from err 509 510 def do_parse(self, rstlist, node): 511 """Parse rST source lines and add them to the specified node 512 513 Take the list of rST source lines rstlist, parse them as 514 rST, and add the resulting docutils nodes as children of node. 515 The nodes are parsed in a way that allows them to include 516 subheadings (titles) without confusing the rendering of 517 anything else. 518 """ 519 # This is from kerneldoc.py -- it works around an API change in 520 # Sphinx between 1.6 and 1.7. Unlike kerneldoc.py, we use 521 # sphinx.util.nodes.nested_parse_with_titles() rather than the 522 # plain self.state.nested_parse(), and so we can drop the saving 523 # of title_styles and section_level that kerneldoc.py does, 524 # because nested_parse_with_titles() does that for us. 525 if Use_SSI: 526 with switch_source_input(self.state, rstlist): 527 nested_parse_with_titles(self.state, rstlist, node) 528 else: 529 save = self.state.memo.reporter 530 self.state.memo.reporter = AutodocReporter( 531 rstlist, self.state.memo.reporter) 532 try: 533 nested_parse_with_titles(self.state, rstlist, node) 534 finally: 535 self.state.memo.reporter = save 536 537 538def setup(app): 539 """ Register qapi-doc directive with Sphinx""" 540 app.add_config_value('qapidoc_srctree', None, 'env') 541 app.add_directive('qapi-doc', QAPIDocDirective) 542 543 return dict( 544 version=__version__, 545 parallel_read_safe=True, 546 parallel_write_safe=True 547 ) 548