xref: /openbmc/qemu/docs/sphinx/qapi_domain.py (revision 3d9a23f92f35afd16dfa5aaf52ede850de54560c)
1"""
2QAPI domain extension.
3"""
4
5from __future__ import annotations
6
7from typing import (
8    TYPE_CHECKING,
9    AbstractSet,
10    Any,
11    Dict,
12    Iterable,
13    List,
14    NamedTuple,
15    Optional,
16    Tuple,
17    cast,
18)
19
20from docutils import nodes
21from docutils.parsers.rst import directives
22
23from compat import KeywordNode, SpaceNode
24from sphinx import addnodes
25from sphinx.addnodes import desc_signature, pending_xref
26from sphinx.directives import ObjectDescription
27from sphinx.domains import (
28    Domain,
29    Index,
30    IndexEntry,
31    ObjType,
32)
33from sphinx.locale import _, __
34from sphinx.roles import XRefRole
35from sphinx.util import logging
36from sphinx.util.docfields import GroupedField, TypedField
37from sphinx.util.nodes import make_id, make_refnode
38
39
40if TYPE_CHECKING:
41    from docutils.nodes import Element, Node
42
43    from sphinx.application import Sphinx
44    from sphinx.builders import Builder
45    from sphinx.environment import BuildEnvironment
46    from sphinx.util.typing import OptionSpec
47
48logger = logging.getLogger(__name__)
49
50
51class ObjectEntry(NamedTuple):
52    docname: str
53    node_id: str
54    objtype: str
55    aliased: bool
56
57
58class QAPIXRefRole(XRefRole):
59
60    def process_link(
61        self,
62        env: BuildEnvironment,
63        refnode: Element,
64        has_explicit_title: bool,
65        title: str,
66        target: str,
67    ) -> tuple[str, str]:
68        refnode["qapi:module"] = env.ref_context.get("qapi:module")
69
70        # Cross-references that begin with a tilde adjust the title to
71        # only show the reference without a leading module, even if one
72        # was provided. This is a Sphinx-standard syntax; give it
73        # priority over QAPI-specific type markup below.
74        hide_module = False
75        if target.startswith("~"):
76            hide_module = True
77            target = target[1:]
78
79        # Type names that end with "?" are considered optional
80        # arguments and should be documented as such, but it's not
81        # part of the xref itself.
82        if target.endswith("?"):
83            refnode["qapi:optional"] = True
84            target = target[:-1]
85
86        # Type names wrapped in brackets denote lists. strip the
87        # brackets and remember to add them back later.
88        if target.startswith("[") and target.endswith("]"):
89            refnode["qapi:array"] = True
90            target = target[1:-1]
91
92        if has_explicit_title:
93            # Don't mess with the title at all if it was explicitly set.
94            # Explicit title syntax for references is e.g.
95            # :qapi:type:`target <explicit title>`
96            # and this explicit title overrides everything else here.
97            return title, target
98
99        title = target
100        if hide_module:
101            title = target.split(".")[-1]
102
103        return title, target
104
105
106# Alias for the return of handle_signature(), which is used in several places.
107# (In the Python domain, this is Tuple[str, str] instead.)
108Signature = str
109
110
111class QAPIDescription(ObjectDescription[Signature]):
112    """
113    Generic QAPI description.
114
115    This is meant to be an abstract class, not instantiated
116    directly. This class handles the abstract details of indexing, the
117    TOC, and reference targets for QAPI descriptions.
118    """
119
120    def handle_signature(self, sig: str, signode: desc_signature) -> Signature:
121        # Do nothing. The return value here is the "name" of the entity
122        # being documented; for QAPI, this is the same as the
123        # "signature", which is just a name.
124
125        # Normally this method must also populate signode with nodes to
126        # render the signature; here we do nothing instead - the
127        # subclasses will handle this.
128        return sig
129
130    def get_index_text(self, name: Signature) -> Tuple[str, str]:
131        """Return the text for the index entry of the object."""
132
133        # NB: this is used for the global index, not the QAPI index.
134        return ("single", f"{name} (QMP {self.objtype})")
135
136    def add_target_and_index(
137        self, name: Signature, sig: str, signode: desc_signature
138    ) -> None:
139        # name is the return value of handle_signature.
140        # sig is the original, raw text argument to handle_signature.
141        # For QAPI, these are identical, currently.
142
143        assert self.objtype
144
145        # If we're documenting a module, don't include the module as
146        # part of the FQN.
147        modname = ""
148        if self.objtype != "module":
149            modname = self.options.get(
150                "module", self.env.ref_context.get("qapi:module")
151            )
152        fullname = (modname + "." if modname else "") + name
153
154        node_id = make_id(
155            self.env, self.state.document, self.objtype, fullname
156        )
157        signode["ids"].append(node_id)
158
159        self.state.document.note_explicit_target(signode)
160        domain = cast(QAPIDomain, self.env.get_domain("qapi"))
161        domain.note_object(fullname, self.objtype, node_id, location=signode)
162
163        if "no-index-entry" not in self.options:
164            arity, indextext = self.get_index_text(name)
165            assert self.indexnode is not None
166            if indextext:
167                self.indexnode["entries"].append(
168                    (arity, indextext, node_id, "", None)
169                )
170
171    def _object_hierarchy_parts(
172        self, sig_node: desc_signature
173    ) -> Tuple[str, ...]:
174        if "fullname" not in sig_node:
175            return ()
176        modname = sig_node.get("module")
177        fullname = sig_node["fullname"]
178
179        if modname:
180            return (modname, *fullname.split("."))
181
182        return tuple(fullname.split("."))
183
184    def _toc_entry_name(self, sig_node: desc_signature) -> str:
185        # This controls the name in the TOC and on the sidebar.
186
187        # This is the return type of _object_hierarchy_parts().
188        toc_parts = cast(Tuple[str, ...], sig_node.get("_toc_parts", ()))
189        if not toc_parts:
190            return ""
191
192        config = self.env.app.config
193        *parents, name = toc_parts
194        if config.toc_object_entries_show_parents == "domain":
195            return sig_node.get("fullname", name)
196        if config.toc_object_entries_show_parents == "hide":
197            return name
198        if config.toc_object_entries_show_parents == "all":
199            return ".".join(parents + [name])
200        return ""
201
202
203class QAPIObject(QAPIDescription):
204    """
205    Description of a generic QAPI object.
206
207    It's not used directly, but is instead subclassed by specific directives.
208    """
209
210    # Inherit some standard options from Sphinx's ObjectDescription
211    option_spec: OptionSpec = (  # type:ignore[misc]
212        ObjectDescription.option_spec.copy()
213    )
214    option_spec.update(
215        {
216            # Borrowed from the Python domain:
217            "module": directives.unchanged,  # Override contextual module name
218            # These are QAPI originals:
219            "since": directives.unchanged,
220        }
221    )
222
223    doc_field_types = [
224        # :feat name: descr
225        GroupedField(
226            "feature",
227            label=_("Features"),
228            names=("feat",),
229            can_collapse=False,
230        ),
231    ]
232
233    def get_signature_prefix(self) -> List[nodes.Node]:
234        """Return a prefix to put before the object name in the signature."""
235        assert self.objtype
236        return [
237            KeywordNode("", self.objtype.title()),
238            SpaceNode(" "),
239        ]
240
241    def get_signature_suffix(self) -> List[nodes.Node]:
242        """Return a suffix to put after the object name in the signature."""
243        ret: List[nodes.Node] = []
244
245        if "since" in self.options:
246            ret += [
247                SpaceNode(" "),
248                addnodes.desc_sig_element(
249                    "", f"(Since: {self.options['since']})"
250                ),
251            ]
252
253        return ret
254
255    def handle_signature(self, sig: str, signode: desc_signature) -> Signature:
256        """
257        Transform a QAPI definition name into RST nodes.
258
259        This method was originally intended for handling function
260        signatures. In the QAPI domain, however, we only pass the
261        definition name as the directive argument and handle everything
262        else in the content body with field lists.
263
264        As such, the only argument here is "sig", which is just the QAPI
265        definition name.
266        """
267        modname = self.options.get(
268            "module", self.env.ref_context.get("qapi:module")
269        )
270
271        signode["fullname"] = sig
272        signode["module"] = modname
273        sig_prefix = self.get_signature_prefix()
274        if sig_prefix:
275            signode += addnodes.desc_annotation(
276                str(sig_prefix), "", *sig_prefix
277            )
278        signode += addnodes.desc_name(sig, sig)
279        signode += self.get_signature_suffix()
280
281        return sig
282
283
284class QAPICommand(QAPIObject):
285    """Description of a QAPI Command."""
286
287    doc_field_types = QAPIObject.doc_field_types.copy()
288    doc_field_types.extend(
289        [
290            # :arg TypeName ArgName: descr
291            TypedField(
292                "argument",
293                label=_("Arguments"),
294                names=("arg",),
295                can_collapse=False,
296            ),
297        ]
298    )
299
300
301class QAPIModule(QAPIDescription):
302    """
303    Directive to mark description of a new module.
304
305    This directive doesn't generate any special formatting, and is just
306    a pass-through for the content body. Named section titles are
307    allowed in the content body.
308
309    Use this directive to create entries for the QAPI module in the
310    global index and the QAPI index; as well as to associate subsequent
311    definitions with the module they are defined in for purposes of
312    search and QAPI index organization.
313
314    :arg: The name of the module.
315    :opt no-index: Don't add cross-reference targets or index entries.
316    :opt no-typesetting: Don't render the content body (but preserve any
317       cross-reference target IDs in the squelched output.)
318
319    Example::
320
321       .. qapi:module:: block-core
322          :no-index:
323          :no-typesetting:
324
325          Lorem ipsum, dolor sit amet ...
326    """
327
328    def run(self) -> List[Node]:
329        modname = self.arguments[0].strip()
330        self.env.ref_context["qapi:module"] = modname
331        ret = super().run()
332
333        # ObjectDescription always creates a visible signature bar. We
334        # want module items to be "invisible", however.
335
336        # Extract the content body of the directive:
337        assert isinstance(ret[-1], addnodes.desc)
338        desc_node = ret.pop(-1)
339        assert isinstance(desc_node.children[1], addnodes.desc_content)
340        ret.extend(desc_node.children[1].children)
341
342        # Re-home node_ids so anchor refs still work:
343        node_ids: List[str]
344        if node_ids := [
345            node_id
346            for el in desc_node.children[0].traverse(nodes.Element)
347            for node_id in cast(List[str], el.get("ids", ()))
348        ]:
349            target_node = nodes.target(ids=node_ids)
350            ret.insert(1, target_node)
351
352        return ret
353
354
355class QAPIIndex(Index):
356    """
357    Index subclass to provide the QAPI definition index.
358    """
359
360    # pylint: disable=too-few-public-methods
361
362    name = "index"
363    localname = _("QAPI Index")
364    shortname = _("QAPI Index")
365
366    def generate(
367        self,
368        docnames: Optional[Iterable[str]] = None,
369    ) -> Tuple[List[Tuple[str, List[IndexEntry]]], bool]:
370        assert isinstance(self.domain, QAPIDomain)
371        content: Dict[str, List[IndexEntry]] = {}
372        collapse = False
373
374        # list of all object (name, ObjectEntry) pairs, sorted by name
375        # (ignoring the module)
376        objects = sorted(
377            self.domain.objects.items(),
378            key=lambda x: x[0].split(".")[-1].lower(),
379        )
380
381        for objname, obj in objects:
382            if docnames and obj.docname not in docnames:
383                continue
384
385            # Strip the module name out:
386            objname = objname.split(".")[-1]
387
388            # Add an alphabetical entry:
389            entries = content.setdefault(objname[0].upper(), [])
390            entries.append(
391                IndexEntry(
392                    objname, 0, obj.docname, obj.node_id, obj.objtype, "", ""
393                )
394            )
395
396            # Add a categorical entry:
397            category = obj.objtype.title() + "s"
398            entries = content.setdefault(category, [])
399            entries.append(
400                IndexEntry(objname, 0, obj.docname, obj.node_id, "", "", "")
401            )
402
403        # alphabetically sort categories; type names first, ABC entries last.
404        sorted_content = sorted(
405            content.items(),
406            key=lambda x: (len(x[0]) == 1, x[0]),
407        )
408        return sorted_content, collapse
409
410
411class QAPIDomain(Domain):
412    """QAPI language domain."""
413
414    name = "qapi"
415    label = "QAPI"
416
417    # This table associates cross-reference object types (key) with an
418    # ObjType instance, which defines the valid cross-reference roles
419    # for each object type.
420    object_types: Dict[str, ObjType] = {
421        "module": ObjType(_("module"), "mod", "any"),
422        "command": ObjType(_("command"), "cmd", "any"),
423    }
424
425    # Each of these provides a rST directive,
426    # e.g. .. qapi:module:: block-core
427    directives = {
428        "module": QAPIModule,
429        "command": QAPICommand,
430    }
431
432    # These are all cross-reference roles; e.g.
433    # :qapi:cmd:`query-block`. The keys correlate to the names used in
434    # the object_types table values above.
435    roles = {
436        "mod": QAPIXRefRole(),
437        "cmd": QAPIXRefRole(),
438        "any": QAPIXRefRole(),  # reference *any* type of QAPI object.
439    }
440
441    # Moved into the data property at runtime;
442    # this is the internal index of reference-able objects.
443    initial_data: Dict[str, Dict[str, Tuple[Any]]] = {
444        "objects": {},  # fullname -> ObjectEntry
445    }
446
447    # Index pages to generate; each entry is an Index class.
448    indices = [
449        QAPIIndex,
450    ]
451
452    @property
453    def objects(self) -> Dict[str, ObjectEntry]:
454        ret = self.data.setdefault("objects", {})
455        return ret  # type: ignore[no-any-return]
456
457    def note_object(
458        self,
459        name: str,
460        objtype: str,
461        node_id: str,
462        aliased: bool = False,
463        location: Any = None,
464    ) -> None:
465        """Note a QAPI object for cross reference."""
466        if name in self.objects:
467            other = self.objects[name]
468            if other.aliased and aliased is False:
469                # The original definition found. Override it!
470                pass
471            elif other.aliased is False and aliased:
472                # The original definition is already registered.
473                return
474            else:
475                # duplicated
476                logger.warning(
477                    __(
478                        "duplicate object description of %s, "
479                        "other instance in %s, use :no-index: for one of them"
480                    ),
481                    name,
482                    other.docname,
483                    location=location,
484                )
485        self.objects[name] = ObjectEntry(
486            self.env.docname, node_id, objtype, aliased
487        )
488
489    def clear_doc(self, docname: str) -> None:
490        for fullname, obj in list(self.objects.items()):
491            if obj.docname == docname:
492                del self.objects[fullname]
493
494    def merge_domaindata(
495        self, docnames: AbstractSet[str], otherdata: Dict[str, Any]
496    ) -> None:
497        for fullname, obj in otherdata["objects"].items():
498            if obj.docname in docnames:
499                # Sphinx's own python domain doesn't appear to bother to
500                # check for collisions. Assert they don't happen and
501                # we'll fix it if/when the case arises.
502                assert fullname not in self.objects, (
503                    "bug - collision on merge?"
504                    f" {fullname=} {obj=} {self.objects[fullname]=}"
505                )
506                self.objects[fullname] = obj
507
508    def find_obj(
509        self, modname: str, name: str, typ: Optional[str]
510    ) -> list[tuple[str, ObjectEntry]]:
511        """
512        Find a QAPI object for "name", perhaps using the given module.
513
514        Returns a list of (name, object entry) tuples.
515
516        :param modname: The current module context (if any!)
517                        under which we are searching.
518        :param name: The name of the x-ref to resolve;
519                     may or may not include a leading module.
520        :param type: The role name of the x-ref we're resolving, if provided.
521                     (This is absent for "any" lookups.)
522        """
523        if not name:
524            return []
525
526        names: list[str] = []
527        matches: list[tuple[str, ObjectEntry]] = []
528
529        fullname = name
530        if "." in fullname:
531            # We're searching for a fully qualified reference;
532            # ignore the contextual module.
533            pass
534        elif modname:
535            # We're searching for something from somewhere;
536            # try searching the current module first.
537            # e.g. :qapi:cmd:`query-block` or `query-block` is being searched.
538            fullname = f"{modname}.{name}"
539
540        if typ is None:
541            # type isn't specified, this is a generic xref.
542            # search *all* qapi-specific object types.
543            objtypes: List[str] = list(self.object_types)
544        else:
545            # type is specified and will be a role (e.g. obj, mod, cmd)
546            # convert this to eligible object types (e.g. command, module)
547            # using the QAPIDomain.object_types table.
548            objtypes = self.objtypes_for_role(typ, [])
549
550        if name in self.objects and self.objects[name].objtype in objtypes:
551            names = [name]
552        elif (
553            fullname in self.objects
554            and self.objects[fullname].objtype in objtypes
555        ):
556            names = [fullname]
557        else:
558            # exact match wasn't found; e.g. we are searching for
559            # `query-block` from a different (or no) module.
560            searchname = "." + name
561            names = [
562                oname
563                for oname in self.objects
564                if oname.endswith(searchname)
565                and self.objects[oname].objtype in objtypes
566            ]
567
568        matches = [(oname, self.objects[oname]) for oname in names]
569        if len(matches) > 1:
570            matches = [m for m in matches if not m[1].aliased]
571        return matches
572
573    def resolve_xref(
574        self,
575        env: BuildEnvironment,
576        fromdocname: str,
577        builder: Builder,
578        typ: str,
579        target: str,
580        node: pending_xref,
581        contnode: Element,
582    ) -> nodes.reference | None:
583        modname = node.get("qapi:module")
584        matches = self.find_obj(modname, target, typ)
585
586        if not matches:
587            return None
588
589        if len(matches) > 1:
590            logger.warning(
591                __("more than one target found for cross-reference %r: %s"),
592                target,
593                ", ".join(match[0] for match in matches),
594                type="ref",
595                subtype="qapi",
596                location=node,
597            )
598
599        name, obj = matches[0]
600        return make_refnode(
601            builder, fromdocname, obj.docname, obj.node_id, contnode, name
602        )
603
604    def resolve_any_xref(
605        self,
606        env: BuildEnvironment,
607        fromdocname: str,
608        builder: Builder,
609        target: str,
610        node: pending_xref,
611        contnode: Element,
612    ) -> List[Tuple[str, nodes.reference]]:
613        results: List[Tuple[str, nodes.reference]] = []
614        matches = self.find_obj(node.get("qapi:module"), target, None)
615        for name, obj in matches:
616            rolename = self.role_for_objtype(obj.objtype)
617            assert rolename is not None
618            role = f"qapi:{rolename}"
619            refnode = make_refnode(
620                builder, fromdocname, obj.docname, obj.node_id, contnode, name
621            )
622            results.append((role, refnode))
623        return results
624
625
626def setup(app: Sphinx) -> Dict[str, Any]:
627    app.setup_extension("sphinx.directives")
628    app.add_domain(QAPIDomain)
629
630    return {
631        "version": "1.0",
632        "env_version": 1,
633        "parallel_read_safe": True,
634        "parallel_write_safe": True,
635    }
636