[Qemu-devel] [PATCH v9 08/27] qapi: Provide nicer array names in introspection

[Eric Blake <eblake@redhat.com>]

For the sake of humans reading introspection output, it is nice
to have the name of implicit array types be recognizable as
arrays of the underlying type.  However, while this patch allows
humans to skip from a command with return type "[123]" straight
to the definition of type "123" without having to first inspect
type "[123]", document that this shortcut should not be taken by
client apps.

This makes the resulting introspection string slightly larger by
default (just over 200 bytes), but it's in the noise (less than
0.3% of the overall 70k size of 'query-qmp-capabilities').

Signed-off-by: Eric Blake <eblake@redhat.com>

---
v9: no change
v8: commit message stats on the size increase
v7: no change
v6: no change
---
 docs/qapi-code-gen.txt     | 7 +++++--
 scripts/qapi-introspect.py | 8 +++++---
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt
index 4d8c2fc..ba29bc6 100644
--- a/docs/qapi-code-gen.txt
+++ b/docs/qapi-code-gen.txt
@@ -662,11 +662,14 @@ Example: the SchemaInfo for BlockRef from section Alternate types

 The SchemaInfo for an array type has meta-type "array", and variant
 member "element-type", which names the array's element type.  Array
-types are implicitly defined.
+types are implicitly defined.  For convenience, the array's name may
+resemble the element type; however, clients should examine member
+"element-type" instead of making assumptions based on parsing member
+"name".

 Example: the SchemaInfo for ['str']

-    { "name": "strList", "meta-type": "array",
+    { "name": "[str]", "meta-type": "array",
       "element-type": "str" }

 The SchemaInfo for an enumeration type has meta-type "enum" and
diff --git a/scripts/qapi-introspect.py b/scripts/qapi-introspect.py
index c0dad66..64f2cd0 100644
--- a/scripts/qapi-introspect.py
+++ b/scripts/qapi-introspect.py
@@ -107,10 +107,12 @@ const char %(c_name)s[] = %(c_string)s;
         # characters.
         if isinstance(typ, QAPISchemaBuiltinType):
             return typ.name
+        if isinstance(typ, QAPISchemaArrayType):
+            return '[' + self._use_type(typ.element_type) + ']'
         return self._name(typ.name)

     def _gen_json(self, name, mtype, obj):
-        if mtype != 'command' and mtype != 'event' and mtype != 'builtin':
+        if mtype not in ('command', 'event', 'builtin', 'array'):
             name = self._name(name)
         obj['name'] = name
         obj['meta-type'] = mtype
@@ -136,8 +138,8 @@ const char %(c_name)s[] = %(c_string)s;
         self._gen_json(name, 'enum', {'values': values})

     def visit_array_type(self, name, info, element_type):
-        self._gen_json(name, 'array',
-                       {'element-type': self._use_type(element_type)})
+        element = self._use_type(element_type)
+        self._gen_json('[' + element + ']', 'array', {'element-type': element})

     def visit_object_type_flat(self, name, info, members, variants):
         obj = {'members': [self._gen_member(m) for m in members]}
-- 
2.4.3