From bceae7697ff1711675c26f715b945737bc6849ae Mon Sep 17 00:00:00 2001 From: Wenchao Xia Date: Thu, 6 Mar 2014 17:08:56 -0800 Subject: [PATCH] qapi script: support enum type as discriminator in union 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 Reviewed-by: Markus Armbruster Signed-off-by: Luiz Capitulino --- docs/qapi-code-gen.txt | 8 +++-- scripts/qapi-types.py | 18 +++++++++--- scripts/qapi-visit.py | 29 +++++++++++++------ scripts/qapi.py | 27 ++++++++++++++++- tests/Makefile | 2 +- .../qapi-schema/flat-union-reverse-define.err | 0 .../flat-union-reverse-define.exit | 1 + .../flat-union-reverse-define.json | 17 +++++++++++ .../qapi-schema/flat-union-reverse-define.out | 9 ++++++ 9 files changed, 94 insertions(+), 17 deletions(-) create mode 100644 tests/qapi-schema/flat-union-reverse-define.err create mode 100644 tests/qapi-schema/flat-union-reverse-define.exit create mode 100644 tests/qapi-schema/flat-union-reverse-define.json create mode 100644 tests/qapi-schema/flat-union-reverse-define.out diff --git a/docs/qapi-code-gen.txt b/docs/qapi-code-gen.txt index 0728f36c65..a2e7921601 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 5885bac5ba..10864efc58 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 0baaf606dc..45ce3a957a 100644 --- a/scripts/qapi-visit.py +++ b/scripts/qapi-visit.py @@ -259,10 +259,16 @@ def generate_visit_union(expr): assert not base return generate_visit_anon_union(name, members) - # 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()) - disc_type = '%sKind' % (name) + enum_define = discriminator_find_enum_define(expr) + if enum_define: + # Use the enum type as discriminator + ret = "" + disc_type = 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()) + disc_type = '%sKind' % (name) if base: base_fields = find_struct(base)['data'] @@ -298,15 +304,16 @@ void visit_type_%(name)s(Visitor *m, %(name)s ** obj, const char *name, Error ** pop_indent() if not discriminator: - desc_type = "type" + disc_key = "type" else: - desc_type = discriminator + disc_key = discriminator ret += mcgen(''' - visit_type_%(name)sKind(m, &(*obj)->kind, "%(type)s", &err); + visit_type_%(disc_type)s(m, &(*obj)->kind, "%(disc_key)s", &err); if (!err) { switch ((*obj)->kind) { ''', - name=name, type=desc_type) + disc_type = disc_type, + disc_key = disc_key) for key in members: if not discriminator: @@ -517,7 +524,11 @@ 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 eebc8a7061..2b43ad2f1b 100644 --- a/scripts/qapi.py +++ b/scripts/qapi.py @@ -180,6 +180,25 @@ def find_base_fields(base): return None return base_struct_define['data'] +# Return the discriminator enum define if discriminator is specified as an +# enum type, otherwise return None. +def discriminator_find_enum_define(expr): + base = expr.get('base') + discriminator = expr.get('discriminator') + + if not (discriminator and base): + return None + + base_fields = find_base_fields(base) + if not base_fields: + return None + + discriminator_type = base_fields.get(discriminator) + if not discriminator_type: + return None + + return find_enum(discriminator_type) + def check_union(expr, expr_info): name = expr['union'] base = expr.get('base') @@ -254,11 +273,17 @@ def parse_schema(fp): add_enum(expr['enum'], expr['data']) elif expr.has_key('union'): add_union(expr) - add_enum('%sKind' % expr['union']) elif expr.has_key('type'): add_struct(expr) exprs.append(expr) + # Try again for hidden UnionKind enum + for expr_elem in schema.exprs: + expr = expr_elem['expr'] + if expr.has_key('union'): + if not discriminator_find_enum_define(expr): + add_enum('%sKind' % expr['union']) + try: check_exprs(schema) except QAPIExprError, e: diff --git a/tests/Makefile b/tests/Makefile index 6ac988932b..88fca31276 100644 --- a/tests/Makefile +++ b/tests/Makefile @@ -145,7 +145,7 @@ check-qapi-schema-y := $(addprefix tests/qapi-schema/, \ unclosed-list.json unclosed-object.json unclosed-string.json \ duplicate-key.json union-invalid-base.json flat-union-no-base.json \ flat-union-invalid-discriminator.json \ - flat-union-invalid-branch-key.json) + flat-union-invalid-branch-key.json flat-union-reverse-define.json) GENERATED_HEADERS += tests/test-qapi-types.h tests/test-qapi-visit.h tests/test-qmp-commands.h diff --git a/tests/qapi-schema/flat-union-reverse-define.err b/tests/qapi-schema/flat-union-reverse-define.err new file mode 100644 index 0000000000..e69de29bb2 diff --git a/tests/qapi-schema/flat-union-reverse-define.exit b/tests/qapi-schema/flat-union-reverse-define.exit new file mode 100644 index 0000000000..573541ac97 --- /dev/null +++ b/tests/qapi-schema/flat-union-reverse-define.exit @@ -0,0 +1 @@ +0 diff --git a/tests/qapi-schema/flat-union-reverse-define.json b/tests/qapi-schema/flat-union-reverse-define.json new file mode 100644 index 0000000000..9ea7e72201 --- /dev/null +++ b/tests/qapi-schema/flat-union-reverse-define.json @@ -0,0 +1,17 @@ +{ 'union': 'TestUnion', + 'base': 'TestBase', + 'discriminator': 'enum1', + 'data': { 'value1': 'TestTypeA', + 'value2': 'TestTypeB' } } + +{ 'type': 'TestBase', + 'data': { 'enum1': 'TestEnum' } } + +{ 'enum': 'TestEnum', + 'data': [ 'value1', 'value2' ] } + +{ 'type': 'TestTypeA', + 'data': { 'string': 'str' } } + +{ 'type': 'TestTypeB', + 'data': { 'integer': 'int' } } diff --git a/tests/qapi-schema/flat-union-reverse-define.out b/tests/qapi-schema/flat-union-reverse-define.out new file mode 100644 index 0000000000..03c952e28a --- /dev/null +++ b/tests/qapi-schema/flat-union-reverse-define.out @@ -0,0 +1,9 @@ +[OrderedDict([('union', 'TestUnion'), ('base', 'TestBase'), ('discriminator', 'enum1'), ('data', OrderedDict([('value1', 'TestTypeA'), ('value2', 'TestTypeB')]))]), + OrderedDict([('type', 'TestBase'), ('data', OrderedDict([('enum1', 'TestEnum')]))]), + OrderedDict([('enum', 'TestEnum'), ('data', ['value1', 'value2'])]), + OrderedDict([('type', 'TestTypeA'), ('data', OrderedDict([('string', 'str')]))]), + OrderedDict([('type', 'TestTypeB'), ('data', OrderedDict([('integer', 'int')]))])] +[{'enum_name': 'TestEnum', 'enum_values': ['value1', 'value2']}] +[OrderedDict([('type', 'TestBase'), ('data', OrderedDict([('enum1', 'TestEnum')]))]), + OrderedDict([('type', 'TestTypeA'), ('data', OrderedDict([('string', 'str')]))]), + OrderedDict([('type', 'TestTypeB'), ('data', OrderedDict([('integer', 'int')]))])]