Hi On Wed, Sep 8, 2021 at 4:12 PM Markus Armbruster <arm...@redhat.com> wrote:
> marcandre.lur...@redhat.com writes: > > > From: Marc-André Lureau <marcandre.lur...@redhat.com> > > > > The argument isn't owned by the callee, so it better be const. > > But a lot of code in QEMU rely on non-const arguments to tweak it (steal > > values etc). > > > > Since Rust types / bindings are derived from the C version, we have to > > be more accurate there to do correct ownership in the bindings. > > > > Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com> > > --- > > scripts/qapi/schema.py | 15 +++++++++++---- > > 1 file changed, 11 insertions(+), 4 deletions(-) > > > > diff --git a/scripts/qapi/schema.py b/scripts/qapi/schema.py > > index 3d72c7dfc9..1f6301c394 100644 > > --- a/scripts/qapi/schema.py > > +++ b/scripts/qapi/schema.py > > @@ -226,8 +226,15 @@ def c_type(self): > > pass > > > > # Return the C type to be used in a parameter list. > > - def c_param_type(self): > > - return self.c_type() > > + # > > + # The argument should be considered const, since no ownership is > given to > > + # the callee, but qemu C code frequently tweaks it. Set const=True > for a > > + # stricter declaration. > > This comment makes sense only if you're familiar with Rust, where "may > change" is actually tied to ownership. > > Arguably, this semantic can also apply to C. > However, I can't see a use of .c_param_type(True). Sure you need this > patch in this series? > > Indeed it looks like a leftover now. Let's drop it. > + def c_param_type(self, const: bool = False): > > + c_type = self.c_type() > > + if const and c_type.endswith(POINTER_SUFFIX): > > + c_type = 'const ' + c_type > > + return c_type > > > > # Return the C type to be used where we suppress boxing. > > def c_unboxed_type(self): > > @@ -280,10 +287,10 @@ def c_name(self): > > def c_type(self): > > return self._c_type_name > > > > - def c_param_type(self): > > + def c_param_type(self, const: bool = False): > > if self.name == 'str': > > return 'const ' + self._c_type_name > > - return self._c_type_name > > + return super().c_param_type(const) > > Would > > def c_param_type(self, const: bool = False): > return super().c_param_type(const or self.name == 'str') > > do? > > > > > def json_type(self): > > return self._json_type_name > > > -- Marc-André Lureau
