From e16b73179937ed7b30c594f9c2414e69b9c96b97 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Wed, 21 Feb 2018 22:54:15 -0500 Subject: [PATCH] qapi: Allow anonymous base for flat union Rather than requiring all flat unions to explicitly create a separate base struct, we can allow the qapi schema to specify the common members via an inline dictionary. This is similar to how commands can specify an inline anonymous type for its 'data'. We already have several struct types that only exist to serve as a single flat union's base; the next commit will clean them up. In particular, this patch's change to the BlockdevOptions example in qapi-code-gen.txt will actually be done in the real QAPI schema. Now that anonymous bases are legal, we need to rework the flat-union-bad-base negative test (as previously written, it forms what is now valid QAPI; tweak it to now provide coverage of a new error message path), and add a positive test in qapi-schema-test to use an anonymous base (making the integer argument optional, for even more coverage). Note that this patch only allows anonymous bases for flat unions; simple unions are already enough syntactic sugar that we do not want to burden them further. Meanwhile, while it would be easy to also allow an anonymous base for structs, that would be quite redundant, as the members can be put right into the struct instead. Backports commit ac4338f8eb783fd421aae492ca262a586918471e from qemu --- qemu/scripts/qapi-types.py | 10 ++++++---- qemu/scripts/qapi.py | 12 ++++++++++-- 2 files changed, 16 insertions(+), 6 deletions(-) diff --git a/qemu/scripts/qapi-types.py b/qemu/scripts/qapi-types.py index 7fe16694..86e71f25 100644 --- a/qemu/scripts/qapi-types.py +++ b/qemu/scripts/qapi-types.py @@ -73,12 +73,14 @@ struct %(c_name)s { c_name=c_name(name)) if base: - ret += mcgen(''' + if not base.is_implicit(): + ret += mcgen(''' /* Members inherited from %(c_name)s: */ ''', - c_name=base.c_name()) + c_name=base.c_name()) ret += gen_struct_members(base.members) - ret += mcgen(''' + if not base.is_implicit(): + ret += mcgen(''' /* Own members: */ ''') ret += gen_struct_members(members) @@ -258,7 +260,7 @@ class QAPISchemaGenTypeVisitor(QAPISchemaVisitor): return self._fwdecl += gen_fwd_object_or_array(name) self.decl += gen_object(name, base, members, variants) - if base: + if base and not base.is_implicit(): self.decl += gen_upcast(name, base) # TODO Worth changing the visitor signature, so we could # directly use rather than repeat type.is_implicit()? diff --git a/qemu/scripts/qapi.py b/qemu/scripts/qapi.py index 435c6d2f..f010c6c2 100644 --- a/qemu/scripts/qapi.py +++ b/qemu/scripts/qapi.py @@ -332,6 +332,8 @@ class QAPISchemaParser(object): def find_base_members(base): + if isinstance(base, dict): + return base base_struct_define = find_struct(base) if not base_struct_define: return None @@ -565,9 +567,10 @@ def check_union(expr, expr_info): # Else, it's a flat union. else: - # The object must have a string member 'base'. + # The object must have a string or dictionary 'base'. check_type(expr_info, "'base' for union '%s'" % name, - base, allow_metas=['struct']) + base, allow_dict=True, allow_optional=True, + allow_metas=['struct']) if not base: raise QAPIExprError(expr_info, "Flat union '%s' must have a base" @@ -1045,6 +1048,8 @@ class QAPISchemaMember(object): owner = owner[6:] if owner.endswith('-arg'): return '(parameter of %s)' % owner[:-4] + elif owner.endswith('-base'): + return '(base of %s)' % owner[:-5] else: assert owner.endswith('-wrapper') # Unreachable and not implemented @@ -1339,6 +1344,9 @@ class QAPISchema(object): base = expr.get('base') tag_name = expr.get('discriminator') tag_member = None + if isinstance(base, dict): + base = (self._make_implicit_object_type( + name, info, 'base', self._make_members(base, info))) if tag_name: variants = [self._make_variant(key, value) for (key, value) in data.iteritems()]