[RFC PATCH v2 18/35] docs/qapi-domain: add qapi:enum directive

[John Snow]

Add the .. qapi:enum:: directive, object, and :qapi:enum:`name`
cross-reference role.

Add the :value name: field list for documenting Enum values.

Of note, also introduce a new "type" role that is intended to be used by
other QAPI object directives to cross-reference arbitrary QAPI type
names, but will exclude commands, events, and modules from
consideration.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 docs/sphinx/qapi-domain.py | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/docs/sphinx/qapi-domain.py b/docs/sphinx/qapi-domain.py
index c46c87168bd..e37e300e4e6 100644
--- a/docs/sphinx/qapi-domain.py
+++ b/docs/sphinx/qapi-domain.py
@@ -287,6 +287,23 @@ class QAPICommand(QAPIObject):
     )
 
 
+class QAPIEnum(QAPIObject):
+    """Description of a QAPI Enum."""
+
+    doc_field_types = QAPIObject.doc_field_types.copy()
+    doc_field_types.extend(
+        [
+            # :value name: descr
+            GroupedField(
+                "value",
+                label=_("Values"),
+                names=("value",),
+                can_collapse=False,
+            )
+        ]
+    )
+
+
 class QAPIModule(SphinxDirective):
     """
     Directive to mark description of a new module.
@@ -440,9 +457,14 @@ class QAPIDomain(Domain):
     # This table associates cross-reference object types (key) with an
     # ObjType instance, which defines the valid cross-reference roles
     # for each object type.
+    #
+    # e.g., the :qapi:type: cross-reference role can refer to enum,
+    # struct, union, or alternate objects; but :qapi:obj: can refer to
+    # anything. Each object also gets its own targeted cross-reference role.
     object_types: Dict[str, ObjType] = {
         "module": ObjType(_("module"), "mod", "obj"),
         "command": ObjType(_("command"), "cmd", "obj"),
+        "enum": ObjType(_("enum"), "enum", "obj", "type"),
     }
 
     # Each of these provides a rST directive,
@@ -450,6 +472,7 @@ class QAPIDomain(Domain):
     directives = {
         "module": QAPIModule,
         "command": QAPICommand,
+        "enum": QAPIEnum,
     }
 
     # These are all cross-reference roles; e.g.
@@ -458,6 +481,9 @@ class QAPIDomain(Domain):
     roles = {
         "mod": QAPIXRefRole(),
         "cmd": QAPIXRefRole(),
+        "enum": QAPIXRefRole(),
+        # reference any data type (excludes modules, commands, events)
+        "type": QAPIXRefRole(),
         "obj": QAPIXRefRole(),  # reference *any* type of QAPI object.
     }
 
-- 
2.47.0