qapi: Prepare for system modules other than 'builtin'

The next commit wants to generate qapi-emit-events.{c.h}.  To enable
that, extend QAPISchemaModularCVisitor to support additional "system
modules", i.e. modules that don't correspond to a (user-defined) QAPI
schema module.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190214152251.2073-5-armbru@redhat.com>

scripts/qapi/common.py

@@ -2327,27 +2327,42 @@ def __init__(self, prefix, what, blurb, pydoc):
         self._module = {}
         self._main_module = None
 
+    @staticmethod
+    def _is_user_module(name):
+        return name and not name.startswith('./')
+
     @staticmethod
     def _is_builtin_module(name):
         return not name
 
     def _module_basename(self, what, name):
-        if name is None:
-            return re.sub(r'-', '-builtin-', what)
-        basename = os.path.join(os.path.dirname(name),
-                                self._prefix + what)
-        if name == self._main_module:
-            return basename
-        return basename + '-' + os.path.splitext(os.path.basename(name))[0]
+        ret = '' if self._is_builtin_module(name) else self._prefix
+        if self._is_user_module(name):
+            dirname, basename = os.path.split(name)
+            ret += what
+            if name != self._main_module:
+                ret += '-' + os.path.splitext(basename)[0]
+            ret = os.path.join(dirname, ret)
+        else:
+            name = name[2:] if name else 'builtin'
+            ret += re.sub(r'-', '-' + name + '-', what)
+        return ret
 
     def _add_module(self, name, blurb):
-        if self._main_module is None and not self._is_builtin_module(name):
-            self._main_module = name
         genc = QAPIGenC(blurb, self._pydoc)
         genh = QAPIGenH(blurb, self._pydoc)
         self._module[name] = (genc, genh)
         self._set_module(name)
 
+    def _add_user_module(self, name, blurb):
+        assert self._is_user_module(name)
+        if self._main_module is None:
+            self._main_module = name
+        self._add_module(name, blurb)
+
+    def _add_system_module(self, name, blurb):
+        self._add_module(name and './' + name, blurb)
+
     def _set_module(self, name):
         self._genc, self._genh = self._module[name]
 
@@ -2372,7 +2387,7 @@ def visit_module(self, name):
             self._genc = None
             self._genh = None
         else:
-            self._add_module(name, self._blurb)
+            self._add_user_module(name, self._blurb)
             self._begin_user_module(name)
 
     def visit_include(self, name, info):

scripts/qapi/types.py

@@ -183,7 +183,7 @@ def __init__(self, prefix):
         QAPISchemaModularCVisitor.__init__(
             self, prefix, 'qapi-types', ' * Schema-defined QAPI types',
             __doc__)
-        self._add_module(None, ' * Built-in QAPI types')
+        self._add_system_module(None, ' * Built-in QAPI types')
         self._genc.preamble_add(mcgen('''
 #include "qemu/osdep.h"
 #include "qapi/dealloc-visitor.h"

scripts/qapi/visit.py

@@ -284,7 +284,7 @@ def __init__(self, prefix):
         QAPISchemaModularCVisitor.__init__(
             self, prefix, 'qapi-visit', ' * Schema-defined QAPI visitors',
             __doc__)
-        self._add_module(None, ' * Built-in QAPI visitors')
+        self._add_system_module(None, ' * Built-in QAPI visitors')
         self._genc.preamble_add(mcgen('''
 #include "qemu/osdep.h"
 #include "qemu-common.h"