[PATCH v2 36/62] docs/qapidoc: split old implementation into qapidoc_legacy.py

[John Snow <jsnow@redhat.com>]

This is being done primarily to be able to type check and delint the new
implementation without needing to worry about fixing up the old
implementation.

I'm adding the new implementation into the existing file instead of into
a new file so that when the dust settles, qapidoc.py will contain the
full history of development on this generative module.

This patch *should* be pure motion, give or take the import statements.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 docs/sphinx/qapidoc.py        | 420 +-------------------------------
 docs/sphinx/qapidoc_legacy.py | 439 ++++++++++++++++++++++++++++++++++
 2 files changed, 441 insertions(+), 418 deletions(-)
 create mode 100644 docs/sphinx/qapidoc_legacy.py

diff --git a/docs/sphinx/qapidoc.py b/docs/sphinx/qapidoc.py
index dc72f3fd3f3..f4abf42e7bf 100644
--- a/docs/sphinx/qapidoc.py
+++ b/docs/sphinx/qapidoc.py
@@ -25,19 +25,16 @@
 """
 
 import os
-import re
 import sys
-import textwrap
 from typing import List
 
 from docutils import nodes
 from docutils.parsers.rst import Directive, directives
-from docutils.statemachine import ViewList
-from qapi.error import QAPIError, QAPISemError
+from qapi.error import QAPIError
 from qapi.gen import QAPISchemaVisitor
-from qapi.parser import QAPIDoc
 from qapi.schema import QAPISchema
 
+from qapidoc_legacy import QAPISchemaGenRSTVisitor
 from sphinx import addnodes
 from sphinx.directives.code import CodeBlock
 from sphinx.errors import ExtensionError
@@ -48,419 +45,6 @@
 __version__ = "1.0"
 
 
-def dedent(text: str) -> str:
-    # Adjust indentation to make description text parse as paragraph.
-
-    lines = text.splitlines(True)
-    if re.match(r"\s+", lines[0]):
-        # First line is indented; description started on the line after
-        # the name. dedent the whole block.
-        return textwrap.dedent(text)
-
-    # Descr started on same line. Dedent line 2+.
-    return lines[0] + textwrap.dedent("".join(lines[1:]))
-
-
-# Disable black auto-formatter until re-enabled:
-# fmt: off
-
-
-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: condition)'.
-        If with_if is False, we don't return the "(If: " and ")".
-        """
-
-        doc = ifcond.docgen()
-        if not doc:
-            return []
-        doc = nodes.literal('', doc)
-        if not with_if:
-            return [doc]
-
-        nodelist = [nodes.Text(' ('), nodes.strong('', 'If: ')]
-        nodelist.append(doc)
-        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.is_present():
-            term.extend(self._nodes_for_ifcond(member.ifcond))
-        return term
-
-    def _nodes_for_variant_when(self, branches, 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 'branches' part of a definition list.
-        """
-        term = [nodes.Text(' when '),
-                nodes.literal('', branches.tag_member.name),
-                nodes.Text(' is '),
-                nodes.literal('', '"%s"' % variant.name)]
-        if variant.ifcond.is_present():
-            term.extend(self._nodes_for_ifcond(variant.ifcond))
-        return term
-
-    def _nodes_for_members(self, doc, what, base=None, branches=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 = dedent(section.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 branches:
-            for v in branches.variants:
-                if v.type.name == 'q_empty':
-                    continue
-                assert not v.type.is_implicit()
-                term = [nodes.Text('The members of '),
-                        nodes.literal('', v.type.doc_type())]
-                term.extend(self._nodes_for_variant_when(branches, 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.is_present():
-                termtext.extend(self._nodes_for_ifcond(section.member.ifcond))
-            # TODO drop fallbacks when undocumented members are outlawed
-            if section.text:
-                defn = dedent(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, arg_type):
-        """Return list of doctree nodes for the arguments section"""
-        if arg_type and not arg_type.is_implicit():
-            assert not doc.args
-            section = self._make_section('Arguments')
-            dlnode = nodes.definition_list()
-            dlnode += self._make_dlitem(
-                [nodes.Text('The members of '),
-                 nodes.literal('', 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.member.name)], dedent(section.text))
-            seen_item = True
-
-        if not seen_item:
-            return []
-
-        section = self._make_section('Features')
-        section += dlnode
-        return [section]
-
-    def _nodes_for_sections(self, doc):
-        """Return list of doctree nodes for additional sections"""
-        nodelist = []
-        for section in doc.sections:
-            if section.kind == QAPIDoc.Kind.TODO:
-                # Hide TODO: sections
-                continue
-
-            if section.kind == QAPIDoc.Kind.PLAIN:
-                # Sphinx cannot handle sectionless titles;
-                # Instead, just append the results to the prior section.
-                container = nodes.container()
-                self._parse_text_into_node(section.text, container)
-                nodelist += container.children
-                continue
-
-            snode = self._make_section(section.kind.name.title())
-            self._parse_text_into_node(dedent(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.is_present():
-            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, branches):
-        doc = self._cur_doc
-        if base and base.is_implicit():
-            base = None
-        self._add_doc('Object',
-                      self._nodes_for_members(doc, 'Members', base, branches)
-                      + 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,
-                             alternatives):
-        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)
-                      + 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)
-                      + 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)
-        return 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(' ')
-            node = self._start_new_heading(heading, len(leader))
-            if text == '':
-                return
-        else:
-            node = nodes.container()
-
-        self._parse_text_into_node(text, 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_node(self):
-        """Return the root docutils node which makes up the document"""
-        return self._top_node
-
-
-# Turn the black formatter on for the rest of the file.
-# fmt: on
-
-
 class QAPISchemaGenDepVisitor(QAPISchemaVisitor):
     """A QAPI schema visitor which adds Sphinx dependencies each module
 
diff --git a/docs/sphinx/qapidoc_legacy.py b/docs/sphinx/qapidoc_legacy.py
new file mode 100644
index 00000000000..679f38356b1
--- /dev/null
+++ b/docs/sphinx/qapidoc_legacy.py
@@ -0,0 +1,439 @@
+# 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 re
+import textwrap
+
+from docutils import nodes
+from docutils.statemachine import ViewList
+from qapi.error import QAPISemError
+from qapi.gen import QAPISchemaVisitor
+from qapi.parser import QAPIDoc
+
+
+def dedent(text: str) -> str:
+    # Adjust indentation to make description text parse as paragraph.
+
+    lines = text.splitlines(True)
+    if re.match(r"\s+", lines[0]):
+        # First line is indented; description started on the line after
+        # the name. dedent the whole block.
+        return textwrap.dedent(text)
+
+    # Descr started on same line. Dedent line 2+.
+    return lines[0] + textwrap.dedent("".join(lines[1:]))
+
+
+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: condition)'.
+        If with_if is False, we don't return the "(If: " and ")".
+        """
+
+        doc = ifcond.docgen()
+        if not doc:
+            return []
+        doc = nodes.literal('', doc)
+        if not with_if:
+            return [doc]
+
+        nodelist = [nodes.Text(' ('), nodes.strong('', 'If: ')]
+        nodelist.append(doc)
+        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.is_present():
+            term.extend(self._nodes_for_ifcond(member.ifcond))
+        return term
+
+    def _nodes_for_variant_when(self, branches, 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 'branches' part of a definition list.
+        """
+        term = [nodes.Text(' when '),
+                nodes.literal('', branches.tag_member.name),
+                nodes.Text(' is '),
+                nodes.literal('', '"%s"' % variant.name)]
+        if variant.ifcond.is_present():
+            term.extend(self._nodes_for_ifcond(variant.ifcond))
+        return term
+
+    def _nodes_for_members(self, doc, what, base=None, branches=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 = dedent(section.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 branches:
+            for v in branches.variants:
+                if v.type.name == 'q_empty':
+                    continue
+                assert not v.type.is_implicit()
+                term = [nodes.Text('The members of '),
+                        nodes.literal('', v.type.doc_type())]
+                term.extend(self._nodes_for_variant_when(branches, 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.is_present():
+                termtext.extend(self._nodes_for_ifcond(section.member.ifcond))
+            # TODO drop fallbacks when undocumented members are outlawed
+            if section.text:
+                defn = dedent(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, arg_type):
+        """Return list of doctree nodes for the arguments section"""
+        if arg_type and not arg_type.is_implicit():
+            assert not doc.args
+            section = self._make_section('Arguments')
+            dlnode = nodes.definition_list()
+            dlnode += self._make_dlitem(
+                [nodes.Text('The members of '),
+                 nodes.literal('', 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.member.name)], dedent(section.text))
+            seen_item = True
+
+        if not seen_item:
+            return []
+
+        section = self._make_section('Features')
+        section += dlnode
+        return [section]
+
+    def _nodes_for_sections(self, doc):
+        """Return list of doctree nodes for additional sections"""
+        nodelist = []
+        for section in doc.sections:
+            if section.kind == QAPIDoc.Kind.TODO:
+                # Hide TODO: sections
+                continue
+
+            if section.kind == QAPIDoc.Kind.PLAIN:
+                # Sphinx cannot handle sectionless titles;
+                # Instead, just append the results to the prior section.
+                container = nodes.container()
+                self._parse_text_into_node(section.text, container)
+                nodelist += container.children
+                continue
+
+            snode = self._make_section(section.kind.name.title())
+            self._parse_text_into_node(dedent(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.is_present():
+            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, branches):
+        doc = self._cur_doc
+        if base and base.is_implicit():
+            base = None
+        self._add_doc('Object',
+                      self._nodes_for_members(doc, 'Members', base, branches)
+                      + 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,
+                             alternatives):
+        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)
+                      + 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)
+                      + 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)
+        return 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(' ')
+            node = self._start_new_heading(heading, len(leader))
+            if text == '':
+                return
+        else:
+            node = nodes.container()
+
+        self._parse_text_into_node(text, 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_node(self):
+        """Return the root docutils node which makes up the document"""
+        return self._top_node
-- 
2.48.1