# coding=utf-8 # # QEMU qapidoc QAPI file parsing extension # # Copyright (c) 2020 Linaro # # This work is licensed under the terms of the GNU GPLv2 or later. # See the COPYING file in the top-level directory. """ qapidoc is a Sphinx extension that implements the qapi-doc directive The purpose of this extension is to read the documentation comments in QAPI schema files, and insert them all into the current document. It implements one new rST directive, "qapi-doc::". Each qapi-doc:: directive takes one argument, which is the pathname of the schema file to process, relative to the source tree. The docs/conf.py file must set the qapidoc_srctree config value to the root of the QEMU source tree. The Sphinx documentation on writing extensions is at: https://www.sphinx-doc.org/en/master/development/index.html """ import os import re from docutils import nodes from docutils.statemachine import ViewList from docutils.parsers.rst import directives, Directive from sphinx.errors import ExtensionError from sphinx.util.nodes import nested_parse_with_titles import sphinx from qapi.gen import QAPISchemaVisitor from qapi.schema import QAPIError, QAPISemError, QAPISchema # Sphinx up to 1.6 uses AutodocReporter; 1.7 and later # use switch_source_input. Check borrowed from kerneldoc.py. Use_SSI = sphinx.__version__[:3] >= '1.7' if Use_SSI: from sphinx.util.docutils import switch_source_input else: from sphinx.ext.autodoc import AutodocReporter __version__ = '1.0' # Function borrowed from pydash, which is under the MIT license def intersperse(iterable, separator): """Yield the members of *iterable* interspersed with *separator*.""" iterable = iter(iterable) yield next(iterable) for item in iterable: yield separator yield item class QAPISchemaGenRSTVisitor(QAPISchemaVisitor): """A QAPI schema visitor which generates docutils/Sphinx nodes This class builds up a tree of docutils/Sphinx nodes corresponding to documentation for the various QAPI objects. To use it, first create a QAPISchemaGenRSTVisitor object, and call its visit_begin() method. Then you can call one of the two methods 'freeform' (to add documentation for a freeform documentation chunk) or 'symbol' (to add documentation for a QAPI symbol). These will cause the visitor to build up the tree of document nodes. Once you've added all the documentation via 'freeform' and 'symbol' method calls, you can call 'get_document_nodes' to get the final list of document nodes (in a form suitable for returning from a Sphinx directive's 'run' method). """ def __init__(self, sphinx_directive): self._cur_doc = None self._sphinx_directive = sphinx_directive self._top_node = nodes.section() self._active_headings = [self._top_node] def _make_dlitem(self, term, defn): """Return a dlitem node with the specified term and definition. term should be a list of Text and literal nodes. defn should be one of: - a string, which will be handed to _parse_text_into_node - a list of Text and literal nodes, which will be put into a paragraph node """ dlitem = nodes.definition_list_item() dlterm = nodes.term('', '', *term) dlitem += dlterm if defn: dldef = nodes.definition() if isinstance(defn, list): dldef += nodes.paragraph('', '', *defn) else: self._parse_text_into_node(defn, dldef) dlitem += dldef return dlitem def _make_section(self, title): """Return a section node with optional title""" section = nodes.section(ids=[self._sphinx_directive.new_serialno()]) if title: section += nodes.title(title, title) return section def _nodes_for_ifcond(self, ifcond, with_if=True): """Return list of Text, literal nodes for the ifcond Return a list which gives text like ' (If: cond1, cond2, cond3)', where the conditions are in literal-text and the commas are not. If with_if is False, we don't return the "(If: " and ")". """ condlist = intersperse([nodes.literal('', c) for c in ifcond], nodes.Text(', ')) if not with_if: return condlist nodelist = [nodes.Text(' ('), nodes.strong('', 'If: ')] nodelist.extend(condlist) nodelist.append(nodes.Text(')')) return nodelist def _nodes_for_one_member(self, member): """Return list of Text, literal nodes for this member Return a list of doctree nodes which give text like 'name: type (optional) (If: ...)' suitable for use as the 'term' part of a definition list item. """ term = [nodes.literal('', member.name)] if member.type.doc_type(): term.append(nodes.Text(': ')) term.append(nodes.literal('', member.type.doc_type())) if member.optional: term.append(nodes.Text(' (optional)')) if member.ifcond: term.extend(self._nodes_for_ifcond(member.ifcond)) return term def _nodes_for_variant_when(self, variants, variant): """Return list of Text, literal nodes for variant 'when' clause Return a list of doctree nodes which give text like 'when tagname is variant (If: ...)' suitable for use in the 'variants' part of a definition list. """ term = [nodes.Text(' when '), nodes.literal('', variants.tag_member.name), nodes.Text(' is '), nodes.literal('', '"%s"' % variant.name)] if variant.ifcond: term.extend(self._nodes_for_ifcond(variant.ifcond)) return term def _nodes_for_members(self, doc, what, base=None, variants=None): """Return list of doctree nodes for the table of members""" dlnode = nodes.definition_list() for section in doc.args.values(): term = self._nodes_for_one_member(section.member) # TODO drop fallbacks when undocumented members are outlawed if section.text: defn = section.text elif (variants and variants.tag_member == section.member and not section.member.type.doc_type()): values = section.member.type.member_names() defn = [nodes.Text('One of ')] defn.extend(intersperse([nodes.literal('', v) for v in values], nodes.Text(', '))) else: defn = [nodes.Text('Not documented')] dlnode += self._make_dlitem(term, defn) if base: dlnode += self._make_dlitem([nodes.Text('The members of '), nodes.literal('', base.doc_type())], None) if variants: for v in variants.variants: if v.type.is_implicit(): assert not v.type.base and not v.type.variants for m in v.type.local_members: term = self._nodes_for_one_member(m) term.extend(self._nodes_for_variant_when(variants, v)) dlnode += self._make_dlitem(term, None) else: term = [nodes.Text('The members of '), nodes.literal('', v.type.doc_type())] term.extend(self._nodes_for_variant_when(variants, v)) dlnode += self._make_dlitem(term, None) if not dlnode.children: return [] section = self._make_section(what) section += dlnode return [section] def _nodes_for_enum_values(self, doc): """Return list of doctree nodes for the table of enum values""" seen_item = False dlnode = nodes.definition_list() for section in doc.args.values(): termtext = [nodes.literal('', section.member.name)] if section.member.ifcond: termtext.extend(self._nodes_for_ifcond(section.member.ifcond)) # TODO drop fallbacks when undocumented members are outlawed if section.text: defn = section.text else: defn = [nodes.Text('Not documented')] dlnode += self._make_dlitem(termtext, defn) seen_item = True if not seen_item: return [] section = self._make_section('Values') section += dlnode return [section] def _nodes_for_arguments(self, doc, boxed_arg_type): """Return list of doctree nodes for the arguments section""" if boxed_arg_type: assert not doc.args section = self._make_section('Arguments') dlnode = nodes.definition_list() dlnode += self._make_dlitem( [nodes.Text('The members of '), nodes.literal('', boxed_arg_type.name)], None) section += dlnode return [section] return self._nodes_for_members(doc, 'Arguments') def _nodes_for_features(self, doc): """Return list of doctree nodes for the table of features""" seen_item = False dlnode = nodes.definition_list() for section in doc.features.values(): dlnode += self._make_dlitem([nodes.literal('', section.name)], section.text) seen_item = True if not seen_item: return [] section = self._make_section('Features') section += dlnode return [section] def _nodes_for_example(self, exampletext): """Return list of doctree nodes for a code example snippet""" return [nodes.literal_block(exampletext, exampletext)] def _nodes_for_sections(self, doc): """Return list of doctree nodes for additional sections""" nodelist = [] for section in doc.sections: snode = self._make_section(section.name) if section.name and section.name.startswith('Example'): snode += self._nodes_for_example(section.text) else: self._parse_text_into_node(section.text, snode) nodelist.append(snode) return nodelist def _nodes_for_if_section(self, ifcond): """Return list of doctree nodes for the "If" section""" nodelist = [] if ifcond: snode = self._make_section('If') snode += nodes.paragraph( '', '', *self._nodes_for_ifcond(ifcond, with_if=False) ) nodelist.append(snode) return nodelist def _add_doc(self, typ, sections): """Add documentation for a command/object/enum... We assume we're documenting the thing defined in self._cur_doc. typ is the type of thing being added ("Command", "Object", etc) sections is a list of nodes for sections to add to the definition. """ doc = self._cur_doc snode = nodes.section(ids=[self._sphinx_directive.new_serialno()]) snode += nodes.title('', '', *[nodes.literal(doc.symbol, doc.symbol), nodes.Text(' (' + typ + ')')]) self._parse_text_into_node(doc.body.text, snode) for s in sections: if s is not None: snode += s self._add_node_to_current_heading(snode) def visit_enum_type(self, name, info, ifcond, features, members, prefix): doc = self._cur_doc self._add_doc('Enum', self._nodes_for_enum_values(doc) + self._nodes_for_features(doc) + self._nodes_for_sections(doc) + self._nodes_for_if_section(ifcond)) def visit_object_type(self, name, info, ifcond, features, base, members, variants): doc = self._cur_doc if base and base.is_implicit(): base = None self._add_doc('Object', self._nodes_for_members(doc, 'Members', base, variants) + self._nodes_for_features(doc) + self._nodes_for_sections(doc) + self._nodes_for_if_section(ifcond)) def visit_alternate_type(self, name, info, ifcond, features, variants): doc = self._cur_doc self._add_doc('Alternate', self._nodes_for_members(doc, 'Members') + self._nodes_for_features(doc) + self._nodes_for_sections(doc) + self._nodes_for_if_section(ifcond)) def visit_command(self, name, info, ifcond, features, arg_type, ret_type, gen, success_response, boxed, allow_oob, allow_preconfig, coroutine): doc = self._cur_doc self._add_doc('Command', self._nodes_for_arguments(doc, arg_type if boxed else None) + self._nodes_for_features(doc) + self._nodes_for_sections(doc) + self._nodes_for_if_section(ifcond)) def visit_event(self, name, info, ifcond, features, arg_type, boxed): doc = self._cur_doc self._add_doc('Event', self._nodes_for_arguments(doc, arg_type if boxed else None) + self._nodes_for_features(doc) + self._nodes_for_sections(doc) + self._nodes_for_if_section(ifcond)) def symbol(self, doc, entity): """Add documentation for one symbol to the document tree This is the main entry point which causes us to add documentation nodes for a symbol (which could be a 'command', 'object', 'event', etc). We do this by calling 'visit' on the schema entity, which will then call back into one of our visit_* methods, depending on what kind of thing this symbol is. """ self._cur_doc = doc entity.visit(self) self._cur_doc = None def _start_new_heading(self, heading, level): """Start a new heading at the specified heading level Create a new section whose title is 'heading' and which is placed in the docutils node tree as a child of the most recent level-1 heading. Subsequent document sections (commands, freeform doc chunks, etc) will be placed as children of this new heading section. """ if len(self._active_headings) < level: raise QAPISemError(self._cur_doc.info, 'Level %d subheading found outside a ' 'level %d heading' % (level, level - 1)) snode = self._make_section(heading) self._active_headings[level - 1] += snode self._active_headings = self._active_headings[:level] self._active_headings.append(snode) def _add_node_to_current_heading(self, node): """Add the node to whatever the current active heading is""" self._active_headings[-1] += node def freeform(self, doc): """Add a piece of 'freeform' documentation to the document tree A 'freeform' document chunk doesn't relate to any particular symbol (for instance, it could be an introduction). If the freeform document starts with a line of the form '= Heading text', this is a section or subsection heading, with the heading level indicated by the number of '=' signs. """ # QAPIDoc documentation says free-form documentation blocks # must have only a body section, nothing else. assert not doc.sections assert not doc.args assert not doc.features self._cur_doc = doc text = doc.body.text if re.match(r'=+ ', text): # Section/subsection heading (if present, will always be # the first line of the block) (heading, _, text) = text.partition('\n') (leader, _, heading) = heading.partition(' ') self._start_new_heading(heading, len(leader)) if text == '': return node = self._make_section(None) self._parse_text_into_node(text, node) self._add_node_to_current_heading(node) self._cur_doc = None def _parse_text_into_node(self, doctext, node): """Parse a chunk of QAPI-doc-format text into the node The doc comment can contain most inline rST markup, including bulleted and enumerated lists. As an extra permitted piece of markup, @var will be turned into ``var``. """ # Handle the "@var means ``var`` case doctext = re.sub(r'@([\w-]+)', r'``\1``', doctext) rstlist = ViewList() for line in doctext.splitlines(): # The reported line number will always be that of the start line # of the doc comment, rather than the actual location of the error. # Being more precise would require overhaul of the QAPIDoc class # to track lines more exactly within all the sub-parts of the doc # comment, as well as counting lines here. rstlist.append(line, self._cur_doc.info.fname, self._cur_doc.info.line) # Append a blank line -- in some cases rST syntax errors get # attributed to the line after one with actual text, and if there # isn't anything in the ViewList corresponding to that then Sphinx # 1.6's AutodocReporter will then misidentify the source/line location # in the error message (usually attributing it to the top-level # .rst file rather than the offending .json file). The extra blank # line won't affect the rendered output. rstlist.append("", self._cur_doc.info.fname, self._cur_doc.info.line) self._sphinx_directive.do_parse(rstlist, node) def get_document_nodes(self): """Return the list of docutils nodes which make up the document""" return self._top_node.children class QAPISchemaGenDepVisitor(QAPISchemaVisitor): """A QAPI schema visitor which adds Sphinx dependencies each module This class calls the Sphinx note_dependency() function to tell Sphinx that the generated documentation output depends on the input schema file associated with each module in the QAPI input. """ def __init__(self, env, qapidir): self._env = env self._qapidir = qapidir def visit_module(self, name): if name != "./builtin": qapifile = self._qapidir + '/' + name self._env.note_dependency(os.path.abspath(qapifile)) super().visit_module(name) class QAPIDocDirective(Directive): """Extract documentation from the specified QAPI .json file""" required_argument = 1 optional_arguments = 1 option_spec = { 'qapifile': directives.unchanged_required } has_content = False def new_serialno(self): """Return a unique new ID string suitable for use as a node's ID""" env = self.state.document.settings.env return 'qapidoc-%d' % env.new_serialno('qapidoc') def run(self): env = self.state.document.settings.env qapifile = env.config.qapidoc_srctree + '/' + self.arguments[0] qapidir = os.path.dirname(qapifile) try: schema = QAPISchema(qapifile) # First tell Sphinx about all the schema files that the # output documentation depends on (including 'qapifile' itself) schema.visit(QAPISchemaGenDepVisitor(env, qapidir)) vis = QAPISchemaGenRSTVisitor(self) vis.visit_begin(schema) for doc in schema.docs: if doc.symbol: vis.symbol(doc, schema.lookup_entity(doc.symbol)) else: vis.freeform(doc) return vis.get_document_nodes() except QAPIError as err: # Launder QAPI parse errors into Sphinx extension errors # so they are displayed nicely to the user raise ExtensionError(str(err)) def do_parse(self, rstlist, node): """Parse rST source lines and add them to the specified node Take the list of rST source lines rstlist, parse them as rST, and add the resulting docutils nodes as children of node. The nodes are parsed in a way that allows them to include subheadings (titles) without confusing the rendering of anything else. """ # This is from kerneldoc.py -- it works around an API change in # Sphinx between 1.6 and 1.7. Unlike kerneldoc.py, we use # sphinx.util.nodes.nested_parse_with_titles() rather than the # plain self.state.nested_parse(), and so we can drop the saving # of title_styles and section_level that kerneldoc.py does, # because nested_parse_with_titles() does that for us. if Use_SSI: with switch_source_input(self.state, rstlist): nested_parse_with_titles(self.state, rstlist, node) else: save = self.state.memo.reporter self.state.memo.reporter = AutodocReporter( rstlist, self.state.memo.reporter) try: nested_parse_with_titles(self.state, rstlist, node) finally: self.state.memo.reporter = save def setup(app): """ Register qapi-doc directive with Sphinx""" app.add_config_value('qapidoc_srctree', None, 'env') app.add_directive('qapi-doc', QAPIDocDirective) return dict( version=__version__, parallel_read_safe=True, parallel_write_safe=True )