[Qemu-devel] [PATCH v8 07/18] qapi: Don't use info as witness of implicit object type

[Eric Blake <eblake@redhat.com>]

A future patch will enable error reporting from the various
QAPISchema*.check() methods.  But to report an error related
to an implicit type, we'll need to associate a location with
the type (the same location as the top-level entity that is
causing the creation of the implicit type), and once we do
that, keying off of whether foo.info exists is no longer a
viable way to determine if foo is an implicit type.

Instead, add an is_implicit() method to QAPISchemaEntity, with
overrides for ObjectType and EnumType, and use that function
where needed.

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

---
v8: separate isinstance back to verbose form, add comments
v7: declare at the Entity level, with an optional argument for
filtering by sub-class
v6: split 11/46 into pieces; don't rename _info yet; rework atop
nicer filtering mechanism, including no need to change visitor
signature
---
 scripts/qapi-types.py |  3 ++-
 scripts/qapi-visit.py |  3 ++-
 scripts/qapi.py       | 22 ++++++++++++++++++----
 3 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
index 2a29c6e..4fe618e 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -235,7 +235,8 @@ class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):

     def visit_needed(self, entity):
         # Visit everything except implicit objects
-        return not isinstance(entity, QAPISchemaObjectType) or entity.info
+        return not (entity.is_implicit() and
+                    isinstance(entity, QAPISchemaObjectType))

     def _gen_type_cleanup(self, name):
         self.decl += gen_type_cleanup_decl(name)
diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py
index 9fc79a7..2a9fab8 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -335,7 +335,8 @@ class QAPISchemaGenVisitVisitor(QAPISchemaVisitor):

     def visit_needed(self, entity):
         # Visit everything except implicit objects
-        return not isinstance(entity, QAPISchemaObjectType) or entity.info
+        return not (entity.is_implicit() and
+                    isinstance(entity, QAPISchemaObjectType))

     def visit_enum_type(self, name, info, values, prefix):
         self.decl += gen_visit_decl(name, scalar=True)
diff --git a/scripts/qapi.py b/scripts/qapi.py
index 68f97a1..e263ecf 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -798,6 +798,9 @@ class QAPISchemaEntity(object):
     def check(self, schema):
         pass

+    def is_implicit(self):
+        return not self.info
+
     def visit(self, visitor):
         pass

@@ -900,6 +903,10 @@ class QAPISchemaEnumType(QAPISchemaType):
     def check(self, schema):
         assert len(set(self.values)) == len(self.values)

+    def is_implicit(self):
+        # See QAPISchema._make_implicit_enum_type()
+        return self.name[-4:] == 'Kind'
+
     def c_type(self, is_param=False):
         return c_name(self.name)

@@ -970,12 +977,16 @@ class QAPISchemaObjectType(QAPISchemaType):
             self.variants.check(schema, members, seen)
         self.members = members

+    def is_implicit(self):
+        # See QAPISchema._make_implicit_object_type()
+        return self.name[0] == ':'
+
     def c_name(self):
-        assert self.info
+        assert not self.is_implicit()
         return QAPISchemaType.c_name(self)

     def c_type(self, is_param=False):
-        assert self.info
+        assert not self.is_implicit()
         return QAPISchemaType.c_type(self)

     def json_type(self):
@@ -1043,7 +1054,8 @@ class QAPISchemaObjectTypeVariant(QAPISchemaObjectTypeMember):
     # This function exists to support ugly simple union special cases
     # TODO get rid of them, and drop the function
     def simple_union_type(self):
-        if isinstance(self.type, QAPISchemaObjectType) and not self.type.info:
+        if (self.type.is_implicit() and
+                isinstance(self.type, QAPISchemaObjectType)):
             assert len(self.type.members) == 1
             assert not self.type.variants
             return self.type.members[0].type
@@ -1162,11 +1174,13 @@ class QAPISchema(object):
         self._def_entity(self.the_empty_object_type)

     def _make_implicit_enum_type(self, name, values):
-        name = name + 'Kind'
+        name = name + 'Kind'   # Use namespace reserved by add_name()
         self._def_entity(QAPISchemaEnumType(name, None, values, None))
         return name

     def _make_array_type(self, element_type):
+        # TODO fooList namespace is not reserved; user can create collisions,
+        # or abuse our type system with ['fooList'] for 2D array
         name = element_type + 'List'
         if not self.lookup_type(name):
             self._def_entity(QAPISchemaArrayType(name, None, element_type))
-- 
2.4.3