qapi: centralize is_[user|system|builtin]_module methods

Define what a module is and define what kind of a module it is once and
for all, in one place.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20210201193747.2169670-6-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

scripts/qapi/gen.py

@@ -31,7 +31,11 @@
     guardstart,
     mcgen,
 )
-from .schema import QAPISchemaObjectType, QAPISchemaVisitor
+from .schema import (
+    QAPISchemaModule,
+    QAPISchemaObjectType,
+    QAPISchemaVisitor,
+)
 from .source import QAPISourceInfo
 
 
@@ -246,21 +250,14 @@ def __init__(self,
         self._main_module: Optional[str] = None
 
     @staticmethod
-    def _is_user_module(name: Optional[str]) -> bool:
-        return bool(name and not name.startswith('./'))
-
-    @staticmethod
-    def _is_builtin_module(name: Optional[str]) -> bool:
-        return not name
-
-    def _module_dirname(self, name: Optional[str]) -> str:
-        if self._is_user_module(name):
+    def _module_dirname(name: Optional[str]) -> str:
+        if QAPISchemaModule.is_user_module(name):
             return os.path.dirname(name)
         return ''
 
     def _module_basename(self, what: str, name: Optional[str]) -> str:
-        ret = '' if self._is_builtin_module(name) else self._prefix
-        if self._is_user_module(name):
+        ret = '' if QAPISchemaModule.is_builtin_module(name) else self._prefix
+        if QAPISchemaModule.is_user_module(name):
             basename = os.path.basename(name)
             ret += what
             if name != self._main_module:
@@ -282,7 +279,7 @@ def _add_module(self, name: Optional[str], blurb: str) -> None:
         self._genc, self._genh = self._module[name]
 
     def _add_user_module(self, name: str, blurb: str) -> None:
-        assert self._is_user_module(name)
+        assert QAPISchemaModule.is_user_module(name)
         if self._main_module is None:
             self._main_module = name
         self._add_module(name, blurb)
@@ -292,7 +289,7 @@ def _add_system_module(self, name: Optional[str], blurb: str) -> None:
 
     def write(self, output_dir: str, opt_builtins: bool = False) -> None:
         for name in self._module:
-            if self._is_builtin_module(name) and not opt_builtins:
+            if QAPISchemaModule.is_builtin_module(name) and not opt_builtins:
                 continue
             (genc, genh) = self._module[name]
             genc.write(output_dir)

scripts/qapi/schema.py

@@ -141,6 +141,33 @@ def __init__(self, name):
         self.name = name
         self._entity_list = []
 
+    @staticmethod
+    def is_system_module(name: Optional[str]) -> bool:
+        """
+        System modules are internally defined modules.
+
+        Their names start with the "./" prefix.
+        """
+        return name is None or name.startswith('./')
+
+    @classmethod
+    def is_user_module(cls, name: Optional[str]) -> bool:
+        """
+        User modules are those defined by the user in qapi JSON files.
+
+        They do not start with the "./" prefix.
+        """
+        return not cls.is_system_module(name)
+
+    @staticmethod
+    def is_builtin_module(name: Optional[str]) -> bool:
+        """
+        The built-in module is a single System module for the built-in types.
+
+        It is presently always the value 'None'.
+        """
+        return name is None
+
     def add_entity(self, ent):
         self._entity_list.append(ent)
 
@@ -871,8 +898,8 @@ def resolve_type(self, name, info, what):
         return typ
 
     def _module_name(self, fname):
-        if fname is None:
-            return None
+        if QAPISchemaModule.is_system_module(fname):
+            return fname
         return os.path.relpath(fname, self._schema_dir)
 
     def _make_module(self, fname):