By default, any union will automatically generate a enum type as "[UnionName]Kind" in C code, and it is duplicated when the discriminator is specified as a pre-defined enum type in schema. After this patch, the pre-defined enum type will be really used as the switch case condition in generated C code, if discriminator is an enum field.
Signed-off-by: Wenchao Xia <xiaw...@linux.vnet.ibm.com> Reviewed-by: Eric Blake <ebl...@redhat.com> --- docs/qapi-code-gen.txt | 8 ++++++-- scripts/qapi-types.py | 18 ++++++++++++++---- scripts/qapi-visit.py | 23 ++++++++++++++++------- scripts/qapi.py | 4 +++- 4 files changed, 39 insertions(+), 14 deletions(-) diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt index 0728f36..a2e7921 100644 --- a/docs/qapi-code-gen.txt +++ b/docs/qapi-code-gen.txt @@ -123,11 +123,15 @@ And it looks like this on the wire: Flat union types avoid the nesting on the wire. They are used whenever a specific field of the base type is declared as the discriminator ('type' is -then no longer generated). The discriminator must always be a string field. +then no longer generated). The discriminator can be a string field or a +predefined enum field. If it is a string field, a hidden enum type will be +generated as "[UNION_NAME]Kind". If it is an enum field, a compile time check +will be done to verify the correctness. It is recommended to use an enum field. The above example can then be modified as follows: + { 'enum': 'BlockdevDriver', 'data': [ 'raw', 'qcow2' ] } { 'type': 'BlockdevCommonOptions', - 'data': { 'driver': 'str', 'readonly': 'bool' } } + 'data': { 'driver': 'BlockdevDriver', 'readonly': 'bool' } } { 'union': 'BlockdevOptions', 'base': 'BlockdevCommonOptions', 'discriminator': 'driver', diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py index 914f055..5031c4b 100644 --- a/scripts/qapi-types.py +++ b/scripts/qapi-types.py @@ -201,14 +201,21 @@ def generate_union(expr): base = expr.get('base') discriminator = expr.get('discriminator') + enum_define = discriminator_find_enum_define(expr) + if enum_define: + discriminator_type_name = enum_define['enum_name'] + else: + discriminator_type_name = '%sKind' % (name) + ret = mcgen(''' struct %(name)s { - %(name)sKind kind; + %(discriminator_type_name)s kind; union { void *data; ''', - name=name) + name=name, + discriminator_type_name=discriminator_type_name) for key in typeinfo: ret += mcgen(''' @@ -389,8 +396,11 @@ for expr in exprs: fdef.write(generate_enum_lookup(expr['enum'], expr['data'])) elif expr.has_key('union'): ret += generate_fwd_struct(expr['union'], expr['data']) + "\n" - ret += generate_enum('%sKind' % expr['union'], expr['data'].keys()) - fdef.write(generate_enum_lookup('%sKind' % expr['union'], expr['data'].keys())) + enum_define = discriminator_find_enum_define(expr) + if not enum_define: + ret += generate_enum('%sKind' % expr['union'], expr['data'].keys()) + fdef.write(generate_enum_lookup('%sKind' % expr['union'], + expr['data'].keys())) if expr.get('discriminator') == {}: fdef.write(generate_anon_union_qtypes(expr)) else: diff --git a/scripts/qapi-visit.py b/scripts/qapi-visit.py index 1b55924..3240921 100644 --- a/scripts/qapi-visit.py +++ b/scripts/qapi-visit.py @@ -277,10 +277,14 @@ def generate_visit_union(expr): (key, name)) sys.exit(1) - # There will always be a discriminator in the C switch code, by default it - # is an enum type generated silently as "'%sKind' % (name)" - ret = generate_visit_enum('%sKind' % name, members.keys()) - discriminator_type_name = '%sKind' % (name) + # Use the predefined enum type as discriminator + ret = "" + discriminator_type_name = enum_define['enum_name'] + else: + # There will always be a discriminator in the C switch code, by default it + # is an enum type generated silently as "'%sKind' % (name)" + ret = generate_visit_enum('%sKind' % name, members.keys()) + discriminator_type_name = '%sKind' % (name) if base: base_fields = find_struct(base)['data'] @@ -320,11 +324,12 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error ** else: desc_type = discriminator ret += mcgen(''' - visit_type_%(name)sKind(m, &(*obj)->kind, "%(type)s", &err); + visit_type_%(discriminator_type_name)s(m, &(*obj)->kind, "%(type)s", &err); if (!err) { switch ((*obj)->kind) { ''', - name=name, type=desc_type) + discriminator_type_name=discriminator_type_name, + type=desc_type) for key in members: if not discriminator: @@ -538,7 +543,11 @@ for expr in exprs: ret += generate_visit_list(expr['union'], expr['data']) fdef.write(ret) - ret = generate_decl_enum('%sKind' % expr['union'], expr['data'].keys()) + enum_define = discriminator_find_enum_define(expr) + ret = "" + if not enum_define: + ret = generate_decl_enum('%sKind' % expr['union'], + expr['data'].keys()) ret += generate_declaration(expr['union'], expr['data']) fdecl.write(ret) elif expr.has_key('enum'): diff --git a/scripts/qapi.py b/scripts/qapi.py index 28ede6f..50be200 100644 --- a/scripts/qapi.py +++ b/scripts/qapi.py @@ -174,7 +174,9 @@ def parse_schema(fp): add_enum(expr['enum'], expr['data']) elif expr.has_key('union'): add_union(expr) - add_enum('%sKind' % expr['union']) + enum_define = discriminator_find_enum_define(expr) + if not enum_define: + add_enum('%sKind' % expr['union']) elif expr.has_key('type'): add_struct(expr) exprs.append(expr) -- 1.7.1