diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt index 12af1b8cef..0e4bafff08 100644 --- a/docs/qapi-code-gen.txt +++ b/docs/qapi-code-gen.txt @@ -284,7 +284,7 @@ better than open-coding the member to be type 'str'. === Union types === Usage: { 'union': STRING, 'data': DICT } -or: { 'union': STRING, 'data': DICT, 'base': STRUCT-NAME, +or: { 'union': STRING, 'data': DICT, 'base': STRUCT-NAME-OR-DICT, 'discriminator': ENUM-MEMBER-OF-BASE } Union types are used to let the user choose between several different @@ -320,13 +320,16 @@ an implicit C enum 'NameKind' is created, corresponding to the union the union can be named 'max', as this would collide with the implicit enum. The value for each branch can be of any type. -A flat union definition specifies a struct as its base, and -avoids nesting on the wire. All branches of the union must be -complex types, and the top-level members of the union dictionary on -the wire will be combination of members from both the base type and the -appropriate branch type (when merging two dictionaries, there must be -no keys in common). The 'discriminator' member must be the name of a -non-optional enum-typed member of the base struct. +A flat union definition avoids nesting on the wire, and specifies a +set of common members that occur in all variants of the union. The +'base' key must specifiy either a type name (the type must be a +struct, not a union), or a dictionary representing an anonymous type. +All branches of the union must be complex types, and the top-level +members of the union dictionary on the wire will be combination of +members from both the base type and the appropriate branch type (when +merging two dictionaries, there must be no keys in common). The +'discriminator' member must be the name of a non-optional enum-typed +member of the base struct. The following example enhances the above simple union example by adding an optional common member 'read-only', renaming the @@ -334,10 +337,8 @@ discriminator to something more applicable than the simple union's default of 'type', and reducing the number of {} required on the wire: { 'enum': 'BlockdevDriver', 'data': [ 'file', 'qcow2' ] } - { 'struct': 'BlockdevOptionsBase', - 'data': { 'driver': 'BlockdevDriver', '*read-only': 'bool' } } { 'union': 'BlockdevOptions', - 'base': 'BlockdevOptionsBase', + 'base': { 'driver': 'BlockdevDriver', '*read-only': 'bool' }, 'discriminator': 'driver', 'data': { 'file': 'BlockdevOptionsFile', 'qcow2': 'BlockdevOptionsQcow2' } } @@ -366,10 +367,9 @@ union has a struct with a single member named 'data'. That is, is identical on the wire to: { 'enum': 'Enum', 'data': ['one', 'two'] } - { 'struct': 'Base', 'data': { 'type': 'Enum' } } { 'struct': 'Branch1', 'data': { 'data': 'str' } } { 'struct': 'Branch2', 'data': { 'data': 'int' } } - { 'union': 'Flat', 'base': 'Base', 'discriminator': 'type', + { 'union': 'Flat': 'base': { 'type': 'Enum' }, 'discriminator': 'type', 'data': { 'one': 'Branch1', 'two': 'Branch2' } } diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py index 92ae619fa4..e09c8751a9 100644 --- a/scripts/qapi-types.py +++ b/scripts/qapi-types.py @@ -72,12 +72,14 @@ 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) @@ -224,7 +226,7 @@ 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/scripts/qapi.py b/scripts/qapi.py index d91af94759..a38ef52922 100644 --- a/scripts/qapi.py +++ b/scripts/qapi.py @@ -327,6 +327,8 @@ 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 @@ -561,9 +563,10 @@ 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" @@ -1039,6 +1042,8 @@ 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 @@ -1325,6 +1330,9 @@ 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()] diff --git a/tests/qapi-schema/flat-union-bad-base.err b/tests/qapi-schema/flat-union-bad-base.err index 79b8a71eb8..bee24a217a 100644 --- a/tests/qapi-schema/flat-union-bad-base.err +++ b/tests/qapi-schema/flat-union-bad-base.err @@ -1 +1 @@ -tests/qapi-schema/flat-union-bad-base.json:9: 'base' for union 'TestUnion' should be a type name +tests/qapi-schema/flat-union-bad-base.json:8: 'string' (member of TestTypeA) collides with 'string' (base of TestUnion) diff --git a/tests/qapi-schema/flat-union-bad-base.json b/tests/qapi-schema/flat-union-bad-base.json index e2e622bb6e..74dd421708 100644 --- a/tests/qapi-schema/flat-union-bad-base.json +++ b/tests/qapi-schema/flat-union-bad-base.json @@ -1,5 +1,4 @@ -# we require the base to be an existing struct -# TODO: should we allow an anonymous inline base type? +# we allow anonymous base, but enforce no duplicate keys { 'enum': 'TestEnum', 'data': [ 'value1', 'value2' ] } { 'struct': 'TestTypeA', @@ -7,7 +6,7 @@ { 'struct': 'TestTypeB', 'data': { 'integer': 'int' } } { 'union': 'TestUnion', - 'base': { 'enum1': 'TestEnum', 'kind': 'str' }, + 'base': { 'enum1': 'TestEnum', 'string': 'str' }, 'discriminator': 'enum1', 'data': { 'value1': 'TestTypeA', 'value2': 'TestTypeB' } } diff --git a/tests/qapi-schema/qapi-schema-test.json b/tests/qapi-schema/qapi-schema-test.json index e72274811e..f571e1bb34 100644 --- a/tests/qapi-schema/qapi-schema-test.json +++ b/tests/qapi-schema/qapi-schema-test.json @@ -75,14 +75,10 @@ 'base': 'UserDefZero', 'data': { 'string': 'str', 'enum1': 'EnumOne' } } -{ 'struct': 'UserDefUnionBase2', - 'base': 'UserDefZero', - 'data': { 'string': 'str', 'enum1': 'QEnumTwo' } } - # this variant of UserDefFlatUnion defaults to a union that uses members with # allocated types to test corner cases in the cleanup/dealloc visitor { 'union': 'UserDefFlatUnion2', - 'base': 'UserDefUnionBase2', + 'base': { '*integer': 'int', 'string': 'str', 'enum1': 'QEnumTwo' }, 'discriminator': 'enum1', 'data': { 'value1' : 'UserDefC', # intentional forward reference 'value2' : 'UserDefB' } } diff --git a/tests/qapi-schema/qapi-schema-test.out b/tests/qapi-schema/qapi-schema-test.out index d49fe1d184..19cd214f6b 100644 --- a/tests/qapi-schema/qapi-schema-test.out +++ b/tests/qapi-schema/qapi-schema-test.out @@ -66,7 +66,7 @@ object UserDefFlatUnion case value2: UserDefB case value3: UserDefB object UserDefFlatUnion2 - base UserDefUnionBase2 + base q_obj_UserDefFlatUnion2-base tag enum1 case value1: UserDefC case value2: UserDefB @@ -111,10 +111,6 @@ object UserDefUnionBase base UserDefZero member string: str optional=False member enum1: EnumOne optional=False -object UserDefUnionBase2 - base UserDefZero - member string: str optional=False - member enum1: QEnumTwo optional=False object UserDefZero member integer: int optional=False object WrapAlternate @@ -156,6 +152,10 @@ object q_obj_EVENT_D-arg member b: str optional=False member c: str optional=True member enum3: EnumOne optional=True +object q_obj_UserDefFlatUnion2-base + member integer: int optional=True + member string: str optional=False + member enum1: QEnumTwo optional=False object q_obj___org.qemu_x-command-arg member a: __org.qemu_x-EnumList optional=False member b: __org.qemu_x-StructList optional=False