[PATCH 00/11] Drop support for QAPIGen without a file name

[PATCH 00/11] Drop support for QAPIGen without a file name

[Markus Armbruster]

John Snow posted

    [PATCH 09/12] qapi/gen: move write method to QAPIGenC, make fname a str

    QAPIGenC and QAPIGenH in particular depend on fname being defined, but
    we have a usage of QAPIGenCCode that isn't intended to be associated
    with a particular file.

    No problem, move the write method down to the class that actually needs
    it, and keep QAPIGenCCode more abstract.

    Signed-off-by: John Snow <jsnow@redhat.com>
    ---
     scripts/qapi/commands.py |  2 +-
     scripts/qapi/gen.py      | 54 ++++++++++++++++++++--------------------
     2 files changed, 28 insertions(+), 28 deletions(-)

There is just one user of QAPIGen without a file name, and it's
awkward.  Let's get rid of it.

Since my work to get rid of it depends on parts of John's series, and
I'm pressed for time, I include the parts I need in my series.  John,
feel free to pick this into your complete series.

John Snow (6):
  qapi/commands: assert arg_type is not None
  qapi/events: fix visit_event typing
  qapi/main: handle theoretical None-return from re.match()
  qapi/gen: assert that _start_if is not None in _wrap_ifcond
  qapi/gen: use './builtin' for the built-in module name
  qapi/gen: write _genc/_genh access shims

Markus Armbruster (5):
  qapi/gen: Replace ._begin_system_module()
  qapi/gen: Expose a single module name space
  qapi/gen: Support for switching to another module temporarily
  qapi/commands: Simplify command registry generation
  qapi/gen: Drop support for QAPIGen without a file name

 scripts/qapi/commands.py | 60 ++++++++++++++++-----------------
 scripts/qapi/events.py   | 14 ++++----
 scripts/qapi/gen.py      | 72 +++++++++++++++++++++++-----------------
 scripts/qapi/main.py     |  2 ++
 scripts/qapi/types.py    |  2 +-
 scripts/qapi/visit.py    |  2 +-
 6 files changed, 82 insertions(+), 70 deletions(-)

-- 
2.26.2

[PATCH 01/11] qapi/commands: assert arg_type is not None

[Markus Armbruster]

From: John Snow <jsnow@redhat.com>

when boxed is true, expr.py asserts that we must have
arguments. Ultimately, this should mean that if boxed is True, that
arg_type should be defined. Mypy cannot infer this, and does not support
'stateful' type inference, e.g.:

```
if x:
    assert y is not None

...

if x:
    y.etc()
```

does not work, because mypy does not statefully remember the conditional
assertion in the second block. Help mypy out by creating a new local
that it can track more easily.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20201217015927.197287-2-jsnow@redhat.com>
---
 scripts/qapi/commands.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/scripts/qapi/commands.py b/scripts/qapi/commands.py
index 50978090b4..71744f48a3 100644
--- a/scripts/qapi/commands.py
+++ b/scripts/qapi/commands.py
@@ -126,6 +126,9 @@ def gen_marshal(name: str,
                 boxed: bool,
                 ret_type: Optional[QAPISchemaType]) -> str:
     have_args = boxed or (arg_type and not arg_type.is_empty())
+    if have_args:
+        assert arg_type is not None
+        arg_type_c_name = arg_type.c_name()
 
     ret = mcgen('''
 
@@ -147,7 +150,7 @@ def gen_marshal(name: str,
         ret += mcgen('''
     %(c_name)s arg = {0};
 ''',
-                     c_name=arg_type.c_name())
+                     c_name=arg_type_c_name)
 
     ret += mcgen('''
 
@@ -163,7 +166,7 @@ def gen_marshal(name: str,
         ok = visit_check_struct(v, errp);
     }
 ''',
-                     c_arg_type=arg_type.c_name())
+                     c_arg_type=arg_type_c_name)
     else:
         ret += mcgen('''
     ok = visit_check_struct(v, errp);
@@ -193,7 +196,7 @@ out:
         ret += mcgen('''
     visit_type_%(c_arg_type)s_members(v, &arg, NULL);
 ''',
-                     c_arg_type=arg_type.c_name())
+                     c_arg_type=arg_type_c_name)
 
     ret += mcgen('''
     visit_end_struct(v, NULL);
-- 
2.26.2

[PATCH 02/11] qapi/events: fix visit_event typing

[Markus Armbruster]

From: John Snow <jsnow@redhat.com>

Actually, the arg_type can indeed be Optional.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20201217015927.197287-3-jsnow@redhat.com>
---
 scripts/qapi/events.py | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/scripts/qapi/events.py b/scripts/qapi/events.py
index 599f3d1f56..9851653b9d 100644
--- a/scripts/qapi/events.py
+++ b/scripts/qapi/events.py
@@ -12,7 +12,7 @@ This work is licensed under the terms of the GNU GPL, version 2.
 See the COPYING file in the top-level directory.
 """
 
-from typing import List
+from typing import List, Optional
 
 from .common import c_enum_const, c_name, mcgen
 from .gen import QAPISchemaModularCVisitor, build_params, ifcontext
@@ -27,7 +27,7 @@ from .types import gen_enum, gen_enum_lookup
 
 
 def build_event_send_proto(name: str,
-                           arg_type: QAPISchemaObjectType,
+                           arg_type: Optional[QAPISchemaObjectType],
                            boxed: bool) -> str:
     return 'void qapi_event_send_%(c_name)s(%(param)s)' % {
         'c_name': c_name(name.lower()),
@@ -35,7 +35,7 @@ def build_event_send_proto(name: str,
 
 
 def gen_event_send_decl(name: str,
-                        arg_type: QAPISchemaObjectType,
+                        arg_type: Optional[QAPISchemaObjectType],
                         boxed: bool) -> str:
     return mcgen('''
 
@@ -78,7 +78,7 @@ def gen_param_var(typ: QAPISchemaObjectType) -> str:
 
 
 def gen_event_send(name: str,
-                   arg_type: QAPISchemaObjectType,
+                   arg_type: Optional[QAPISchemaObjectType],
                    boxed: bool,
                    event_enum_name: str,
                    event_emit: str) -> str:
@@ -99,6 +99,7 @@ def gen_event_send(name: str,
                 proto=build_event_send_proto(name, arg_type, boxed))
 
     if have_args:
+        assert arg_type is not None
         ret += mcgen('''
     QObject *obj;
     Visitor *v;
@@ -114,6 +115,7 @@ def gen_event_send(name: str,
                  name=name)
 
     if have_args:
+        assert arg_type is not None
         ret += mcgen('''
     v = qobject_output_visitor_new(&obj);
 ''')
@@ -214,7 +216,7 @@ void %(event_emit)s(%(event_enum)s event, QDict *qdict);
                     info: QAPISourceInfo,
                     ifcond: List[str],
                     features: List[QAPISchemaFeature],
-                    arg_type: QAPISchemaObjectType,
+                    arg_type: Optional[QAPISchemaObjectType],
                     boxed: bool) -> None:
         with ifcontext(ifcond, self._genh, self._genc):
             self._genh.add(gen_event_send_decl(name, arg_type, boxed))
-- 
2.26.2

[PATCH 03/11] qapi/main: handle theoretical None-return from re.match()

[Markus Armbruster]

From: John Snow <jsnow@redhat.com>

Mypy cannot understand that this match can never be None, so help it
along.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20201217015927.197287-4-jsnow@redhat.com>
---
 scripts/qapi/main.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/qapi/main.py b/scripts/qapi/main.py
index 42517210b8..703e7ed1ed 100644
--- a/scripts/qapi/main.py
+++ b/scripts/qapi/main.py
@@ -23,6 +23,8 @@ from .visit import gen_visit
 
 def invalid_prefix_char(prefix: str) -> Optional[str]:
     match = re.match(r'([A-Za-z_.-][A-Za-z0-9_.-]*)?', prefix)
+    # match cannot be None, but mypy cannot infer that.
+    assert match is not None
     if match.end() != len(prefix):
         return prefix[match.end()]
     return None
-- 
2.26.2

[PATCH 04/11] qapi/gen: assert that _start_if is not None in _wrap_ifcond

[Markus Armbruster]

From: John Snow <jsnow@redhat.com>

We already assert this in end_if, but that's opaque to mypy. Do it in
_wrap_ifcond instead. Same effect at runtime, but mypy can now infer
the type in _wrap_ifcond's body.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20201217015927.197287-5-jsnow@redhat.com>
---
 scripts/qapi/gen.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/qapi/gen.py b/scripts/qapi/gen.py
index b40f18eee3..a6dc991b1d 100644
--- a/scripts/qapi/gen.py
+++ b/scripts/qapi/gen.py
@@ -130,11 +130,11 @@ class QAPIGenCCode(QAPIGen):
         self._start_if = (ifcond, self._body, self._preamble)
 
     def end_if(self) -> None:
-        assert self._start_if
         self._wrap_ifcond()
         self._start_if = None
 
     def _wrap_ifcond(self) -> None:
+        assert self._start_if
         self._body = _wrap_ifcond(self._start_if[0],
                                   self._start_if[1], self._body)
         self._preamble = _wrap_ifcond(self._start_if[0],
-- 
2.26.2

[PATCH 05/11] qapi/gen: use './builtin' for the built-in module name

[Markus Armbruster]

From: John Snow <jsnow@redhat.com>

Use this in preference to 'None', which helps remove some edge cases in
the typing.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20201217015927.197287-6-jsnow@redhat.com>
---
 scripts/qapi/gen.py | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/scripts/qapi/gen.py b/scripts/qapi/gen.py
index a6dc991b1d..476d0adac4 100644
--- a/scripts/qapi/gen.py
+++ b/scripts/qapi/gen.py
@@ -245,23 +245,23 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
         self._pydoc = pydoc
         self._genc: Optional[QAPIGenC] = None
         self._genh: Optional[QAPIGenH] = None
-        self._module: Dict[Optional[str], Tuple[QAPIGenC, QAPIGenH]] = {}
+        self._module: Dict[str, Tuple[QAPIGenC, QAPIGenH]] = {}
         self._main_module: Optional[str] = None
 
     @staticmethod
-    def _is_user_module(name: Optional[str]) -> bool:
-        return bool(name and not name.startswith('./'))
+    def _is_user_module(name: str) -> bool:
+        return not name.startswith('./')
 
     @staticmethod
-    def _is_builtin_module(name: Optional[str]) -> bool:
-        return not name
+    def _is_builtin_module(name: str) -> bool:
+        return name == './builtin'
 
-    def _module_dirname(self, name: Optional[str]) -> str:
+    def _module_dirname(self, name: str) -> str:
         if self._is_user_module(name):
             return os.path.dirname(name)
         return ''
 
-    def _module_basename(self, what: str, name: Optional[str]) -> str:
+    def _module_basename(self, what: str, name: str) -> str:
         ret = '' if self._is_builtin_module(name) else self._prefix
         if self._is_user_module(name):
             basename = os.path.basename(name)
@@ -269,15 +269,15 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
             if name != self._main_module:
                 ret += '-' + os.path.splitext(basename)[0]
         else:
-            name = name[2:] if name else 'builtin'
-            ret += re.sub(r'-', '-' + name + '-', what)
+            assert name.startswith('./')
+            ret += re.sub(r'-', '-' + name[2:] + '-', what)
         return ret
 
-    def _module_filename(self, what: str, name: Optional[str]) -> str:
+    def _module_filename(self, what: str, name: str) -> str:
         return os.path.join(self._module_dirname(name),
                             self._module_basename(what, name))
 
-    def _add_module(self, name: Optional[str], blurb: str) -> None:
+    def _add_module(self, name: str, blurb: str) -> None:
         basename = self._module_filename(self._what, name)
         genc = QAPIGenC(basename + '.c', blurb, self._pydoc)
         genh = QAPIGenH(basename + '.h', blurb, self._pydoc)
@@ -290,8 +290,8 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
             self._main_module = name
         self._add_module(name, blurb)
 
-    def _add_system_module(self, name: Optional[str], blurb: str) -> None:
-        self._add_module(name and './' + name, blurb)
+    def _add_system_module(self, name: str, blurb: str) -> None:
+        self._add_module('./' + name, blurb)
 
     def write(self, output_dir: str, opt_builtins: bool = False) -> None:
         for name in self._module:
@@ -310,7 +310,7 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
     def visit_module(self, name: Optional[str]) -> None:
         if name is None:
             if self._builtin_blurb:
-                self._add_system_module(None, self._builtin_blurb)
+                self._add_system_module('builtin', self._builtin_blurb)
                 self._begin_system_module(name)
             else:
                 # The built-in module has not been created.  No code may
-- 
2.26.2

[PATCH 06/11] qapi/gen: write _genc/_genh access shims

[Markus Armbruster]

From: John Snow <jsnow@redhat.com>

Many places assume they can access these fields without checking them
first to ensure they are defined. Eliminating the _genc and _genh fields
and replacing them with functional properties that check for correct
state can ease the typing overhead by eliminating the Optional[T] return
type.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20201217015927.197287-9-jsnow@redhat.com>
---
 scripts/qapi/gen.py | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/scripts/qapi/gen.py b/scripts/qapi/gen.py
index 476d0adac4..12ea98fb61 100644
--- a/scripts/qapi/gen.py
+++ b/scripts/qapi/gen.py
@@ -243,11 +243,20 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
         self._user_blurb = user_blurb
         self._builtin_blurb = builtin_blurb
         self._pydoc = pydoc
-        self._genc: Optional[QAPIGenC] = None
-        self._genh: Optional[QAPIGenH] = None
+        self._current_module: Optional[str] = None
         self._module: Dict[str, Tuple[QAPIGenC, QAPIGenH]] = {}
         self._main_module: Optional[str] = None
 
+    @property
+    def _genc(self) -> QAPIGenC:
+        assert self._current_module is not None
+        return self._module[self._current_module][0]
+
+    @property
+    def _genh(self) -> QAPIGenH:
+        assert self._current_module is not None
+        return self._module[self._current_module][1]
+
     @staticmethod
     def _is_user_module(name: str) -> bool:
         return not name.startswith('./')
@@ -282,7 +291,7 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
         genc = QAPIGenC(basename + '.c', blurb, self._pydoc)
         genh = QAPIGenH(basename + '.h', blurb, self._pydoc)
         self._module[name] = (genc, genh)
-        self._genc, self._genh = self._module[name]
+        self._current_module = name
 
     def _add_user_module(self, name: str, blurb: str) -> None:
         assert self._is_user_module(name)
@@ -315,8 +324,7 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
             else:
                 # The built-in module has not been created.  No code may
                 # be generated.
-                self._genc = None
-                self._genh = None
+                self._current_module = None
         else:
             self._add_user_module(name, self._user_blurb)
             self._begin_user_module(name)
-- 
2.26.2

[PATCH 07/11] qapi/gen: Replace ._begin_system_module()

[Markus Armbruster]

QAPISchemaModularCVisitor._begin_system_module() is actually just for
the builtin module.  Rename it to ._begin_builtin_module() and drop
its useless @name parameter.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 scripts/qapi/gen.py   | 4 ++--
 scripts/qapi/types.py | 2 +-
 scripts/qapi/visit.py | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/scripts/qapi/gen.py b/scripts/qapi/gen.py
index 12ea98fb61..67635b6a26 100644
--- a/scripts/qapi/gen.py
+++ b/scripts/qapi/gen.py
@@ -310,7 +310,7 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
             genc.write(output_dir)
             genh.write(output_dir)
 
-    def _begin_system_module(self, name: None) -> None:
+    def _begin_builtin_module(self) -> None:
         pass
 
     def _begin_user_module(self, name: str) -> None:
@@ -320,7 +320,7 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
         if name is None:
             if self._builtin_blurb:
                 self._add_system_module('builtin', self._builtin_blurb)
-                self._begin_system_module(name)
+                self._begin_builtin_module()
             else:
                 # The built-in module has not been created.  No code may
                 # be generated.
diff --git a/scripts/qapi/types.py b/scripts/qapi/types.py
index 2b4916cdaa..dbf58c0b91 100644
--- a/scripts/qapi/types.py
+++ b/scripts/qapi/types.py
@@ -271,7 +271,7 @@ class QAPISchemaGenTypeVisitor(QAPISchemaModularCVisitor):
             prefix, 'qapi-types', ' * Schema-defined QAPI types',
             ' * Built-in QAPI types', __doc__)
 
-    def _begin_system_module(self, name: None) -> None:
+    def _begin_builtin_module(self) -> None:
         self._genc.preamble_add(mcgen('''
 #include "qemu/osdep.h"
 #include "qapi/dealloc-visitor.h"
diff --git a/scripts/qapi/visit.py b/scripts/qapi/visit.py
index 339f152152..568ba35592 100644
--- a/scripts/qapi/visit.py
+++ b/scripts/qapi/visit.py
@@ -305,7 +305,7 @@ class QAPISchemaGenVisitVisitor(QAPISchemaModularCVisitor):
             prefix, 'qapi-visit', ' * Schema-defined QAPI visitors',
             ' * Built-in QAPI visitors', __doc__)
 
-    def _begin_system_module(self, name: None) -> None:
+    def _begin_builtin_module(self) -> None:
         self._genc.preamble_add(mcgen('''
 #include "qemu/osdep.h"
 #include "qapi/error.h"
-- 
2.26.2

[PATCH 08/11] qapi/gen: Expose a single module name space

[Markus Armbruster]

QAPISchemaModularCVisitor attempts to encapsulate the way it splits
the module name space between user modules (name can't start with
'./') and system modules (name is None or starts with './') by
providing separate ._add_user_module() and ._add_system_module(),
where the latter prepends './' to names other than None.

Not worthwhile.  Dumb down to a single ._add_module(), and have the
callers take care of giving system modules names starting with './'.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 scripts/qapi/commands.py |  2 +-
 scripts/qapi/events.py   |  2 +-
 scripts/qapi/gen.py      | 16 +++++-----------
 3 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/scripts/qapi/commands.py b/scripts/qapi/commands.py
index 71744f48a3..4911166339 100644
--- a/scripts/qapi/commands.py
+++ b/scripts/qapi/commands.py
@@ -286,7 +286,7 @@ class QAPISchemaGenCommandVisitor(QAPISchemaModularCVisitor):
                              types=types))
 
     def visit_end(self) -> None:
-        self._add_system_module('init', ' * QAPI Commands initialization')
+        self._add_module('./init', ' * QAPI Commands initialization')
         self._genh.add(mcgen('''
 #include "qapi/qmp/dispatch.h"
 
diff --git a/scripts/qapi/events.py b/scripts/qapi/events.py
index 9851653b9d..079c666ec6 100644
--- a/scripts/qapi/events.py
+++ b/scripts/qapi/events.py
@@ -191,7 +191,7 @@ class QAPISchemaGenEventVisitor(QAPISchemaModularCVisitor):
                              types=types))
 
     def visit_end(self) -> None:
-        self._add_system_module('emit', ' * QAPI Events emission')
+        self._add_module('./emit', ' * QAPI Events emission')
         self._genc.preamble_add(mcgen('''
 #include "qemu/osdep.h"
 #include "%(prefix)sqapi-emit-events.h"
diff --git a/scripts/qapi/gen.py b/scripts/qapi/gen.py
index 67635b6a26..d9f8bac9aa 100644
--- a/scripts/qapi/gen.py
+++ b/scripts/qapi/gen.py
@@ -287,21 +287,15 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
                             self._module_basename(what, name))
 
     def _add_module(self, name: str, blurb: str) -> None:
+        if self._is_user_module(name):
+            if self._main_module is None:
+                self._main_module = name
         basename = self._module_filename(self._what, name)
         genc = QAPIGenC(basename + '.c', blurb, self._pydoc)
         genh = QAPIGenH(basename + '.h', blurb, self._pydoc)
         self._module[name] = (genc, genh)
         self._current_module = name
 
-    def _add_user_module(self, name: str, blurb: str) -> None:
-        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: str, blurb: str) -> None:
-        self._add_module('./' + name, blurb)
-
     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:
@@ -319,14 +313,14 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
     def visit_module(self, name: Optional[str]) -> None:
         if name is None:
             if self._builtin_blurb:
-                self._add_system_module('builtin', self._builtin_blurb)
+                self._add_module('./builtin', self._builtin_blurb)
                 self._begin_builtin_module()
             else:
                 # The built-in module has not been created.  No code may
                 # be generated.
                 self._current_module = None
         else:
-            self._add_user_module(name, self._user_blurb)
+            self._add_module(name, self._user_blurb)
             self._begin_user_module(name)
 
     def visit_include(self, name: str, info: QAPISourceInfo) -> None:
-- 
2.26.2

[PATCH 09/11] qapi/gen: Support for switching to another module temporarily

[Markus Armbruster]

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 scripts/qapi/gen.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/scripts/qapi/gen.py b/scripts/qapi/gen.py
index d9f8bac9aa..cb00229f5d 100644
--- a/scripts/qapi/gen.py
+++ b/scripts/qapi/gen.py
@@ -15,6 +15,7 @@ from contextlib import contextmanager
 import os
 import re
 from typing import (
+    ContextManager,
     Dict,
     Iterator,
     List,
@@ -296,6 +297,13 @@ class QAPISchemaModularCVisitor(QAPISchemaVisitor):
         self._module[name] = (genc, genh)
         self._current_module = name
 
+    @contextmanager
+    def _temp_module(self, name: str) -> ContextManager[None]:
+        old_module = self._current_module
+        self._current_module = name
+        yield
+        self._current_module = old_module
+
     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:
-- 
2.26.2

Re: [PATCH 09/11] qapi/gen: Support for switching to another module temporarily

[John Snow]

On 12/18/20 3:54 PM, Markus Armbruster wrote:
> +    @contextmanager
> +    def _temp_module(self, name: str) -> ContextManager[None]:

Doesn't quite typecheck; we want Iterator[None] -- I think we're typing 
the function that is yet-to-be-decorated -- mypy will handle typing the 
resulting function.

--js

[PATCH 10/11] qapi/commands: Simplify command registry generation

[Markus Armbruster]

QAPISchemaGenCommandVisitor.visit_command() needs to generate the
marshalling function into the current module, and also generate its
registration into the ./init system module.  The latter is done
somewhat awkwardly: .__init__() creates a QAPIGenCCode that will not
be written out, each .visit_command() adds its registration to it, and
.visit_end() copies its contents into the ./init module it creates.

Instead provide the means to temporarily switch to another module.
Create the ./init module in .visit_begin(), and generate its initial
part.  Add registrations to it in .visit_command().  Finish it in
.visit_end().

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 scripts/qapi/commands.py | 49 ++++++++++++++++++----------------------
 1 file changed, 22 insertions(+), 27 deletions(-)

diff --git a/scripts/qapi/commands.py b/scripts/qapi/commands.py
index 4911166339..396485cc1a 100644
--- a/scripts/qapi/commands.py
+++ b/scripts/qapi/commands.py
@@ -23,7 +23,6 @@ from typing import (
 from .common import c_name, mcgen
 from .gen import (
     QAPIGenC,
-    QAPIGenCCode,
     QAPISchemaModularCVisitor,
     build_params,
     ifcontext,
@@ -237,28 +236,11 @@ def gen_register_command(name: str,
     return ret
 
 
-def gen_registry(registry: str, prefix: str) -> str:
-    ret = mcgen('''
-
-void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds)
-{
-    QTAILQ_INIT(cmds);
-
-''',
-                c_prefix=c_name(prefix, protect=False))
-    ret += registry
-    ret += mcgen('''
-}
-''')
-    return ret
-
-
 class QAPISchemaGenCommandVisitor(QAPISchemaModularCVisitor):
     def __init__(self, prefix: str):
         super().__init__(
             prefix, 'qapi-commands',
             ' * Schema-defined QAPI/QMP commands', None, __doc__)
-        self._regy = QAPIGenCCode(None)
         self._visited_ret_types: Dict[QAPIGenC, Set[QAPISchemaType]] = {}
 
     def _begin_user_module(self, name: str) -> None:
@@ -285,7 +267,7 @@ class QAPISchemaGenCommandVisitor(QAPISchemaModularCVisitor):
 ''',
                              types=types))
 
-    def visit_end(self) -> None:
+    def visit_begin(self, schema) -> None:
         self._add_module('./init', ' * QAPI Commands initialization')
         self._genh.add(mcgen('''
 #include "qapi/qmp/dispatch.h"
@@ -293,13 +275,24 @@ class QAPISchemaGenCommandVisitor(QAPISchemaModularCVisitor):
 void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds);
 ''',
                              c_prefix=c_name(self._prefix, protect=False)))
-        self._genc.preamble_add(mcgen('''
+        self._genc.add(mcgen('''
 #include "qemu/osdep.h"
 #include "%(prefix)sqapi-commands.h"
 #include "%(prefix)sqapi-init-commands.h"
+
+void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds)
+{
+    QTAILQ_INIT(cmds);
+
 ''',
-                                      prefix=self._prefix))
-        self._genc.add(gen_registry(self._regy.get_content(), self._prefix))
+                             prefix=self._prefix,
+                             c_prefix=c_name(self._prefix, protect=False)))
+
+    def visit_end(self) -> None:
+        with self._temp_module('./init'):
+            self._genc.add(mcgen('''
+}
+'''))
 
     def visit_command(self,
                       name: str,
@@ -324,15 +317,17 @@ void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds);
         if ret_type and ret_type not in self._visited_ret_types[self._genc]:
             self._visited_ret_types[self._genc].add(ret_type)
             with ifcontext(ret_type.ifcond,
-                           self._genh, self._genc, self._regy):
+                           self._genh, self._genc):
                 self._genc.add(gen_marshal_output(ret_type))
-        with ifcontext(ifcond, self._genh, self._genc, self._regy):
+        with ifcontext(ifcond, self._genh, self._genc):
             self._genh.add(gen_command_decl(name, arg_type, boxed, ret_type))
             self._genh.add(gen_marshal_decl(name))
             self._genc.add(gen_marshal(name, arg_type, boxed, ret_type))
-            self._regy.add(gen_register_command(name, success_response,
-                                                allow_oob, allow_preconfig,
-                                                coroutine))
+        with self._temp_module('./init'):
+            with ifcontext(ifcond, self._genh, self._genc):
+                self._genc.add(gen_register_command(name, success_response,
+                                                    allow_oob, allow_preconfig,
+                                                    coroutine))
 
 
 def gen_commands(schema: QAPISchema,
-- 
2.26.2

Re: [PATCH 10/11] qapi/commands: Simplify command registry generation

[John Snow]

On 12/18/20 3:54 PM, Markus Armbruster wrote:
> QAPISchemaGenCommandVisitor.visit_command() needs to generate the
> marshalling function into the current module, and also generate its
> registration into the ./init system module.  The latter is done
> somewhat awkwardly: .__init__() creates a QAPIGenCCode that will not
> be written out, each .visit_command() adds its registration to it, and
> .visit_end() copies its contents into the ./init module it creates.
> 
> Instead provide the means to temporarily switch to another module.
> Create the ./init module in .visit_begin(), and generate its initial
> part.  Add registrations to it in .visit_command().  Finish it in
> .visit_end().
> 
> Signed-off-by: Markus Armbruster <armbru@redhat.com>
> ---
>   scripts/qapi/commands.py | 49 ++++++++++++++++++----------------------
>   1 file changed, 22 insertions(+), 27 deletions(-)
> 
> diff --git a/scripts/qapi/commands.py b/scripts/qapi/commands.py
> index 4911166339..396485cc1a 100644
> --- a/scripts/qapi/commands.py
> +++ b/scripts/qapi/commands.py
> @@ -23,7 +23,6 @@ from typing import (
>   from .common import c_name, mcgen
>   from .gen import (
>       QAPIGenC,
> -    QAPIGenCCode,
>       QAPISchemaModularCVisitor,
>       build_params,
>       ifcontext,
> @@ -237,28 +236,11 @@ def gen_register_command(name: str,
>       return ret
>   
>   
> -def gen_registry(registry: str, prefix: str) -> str:
> -    ret = mcgen('''
> -
> -void %(c_prefix)sqmp_init_marshal(QmpCommandList *cmds)
> -{
> -    QTAILQ_INIT(cmds);
> -
> -''',
> -                c_prefix=c_name(prefix, protect=False))
> -    ret += registry
> -    ret += mcgen('''
> -}
> -''')
> -    return ret
> -
> -
>   class QAPISchemaGenCommandVisitor(QAPISchemaModularCVisitor):
>       def __init__(self, prefix: str):
>           super().__init__(
>               prefix, 'qapi-commands',
>               ' * Schema-defined QAPI/QMP commands', None, __doc__)
> -        self._regy = QAPIGenCCode(None)
>           self._visited_ret_types: Dict[QAPIGenC, Set[QAPISchemaType]] = {}
>   
>       def _begin_user_module(self, name: str) -> None:
> @@ -285,7 +267,7 @@ class QAPISchemaGenCommandVisitor(QAPISchemaModularCVisitor):
>   ''',
>                                types=types))
>   
> -    def visit_end(self) -> None:
> +    def visit_begin(self, schema) -> None:

visit_begin(self, schema: QAPISchema) -> None: ...

:~)

[PATCH 11/11] qapi/gen: Drop support for QAPIGen without a file name

[Markus Armbruster]

The previous commit removed the only user of QAPIGen(None).  Tighten
the type hint.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 scripts/qapi/gen.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/qapi/gen.py b/scripts/qapi/gen.py
index cb00229f5d..8716689450 100644
--- a/scripts/qapi/gen.py
+++ b/scripts/qapi/gen.py
@@ -37,7 +37,7 @@ from .source import QAPISourceInfo
 
 
 class QAPIGen:
-    def __init__(self, fname: Optional[str]):
+    def __init__(self, fname: str):
         self.fname = fname
         self._preamble = ''
         self._body = ''
-- 
2.26.2