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authorWenchao Xia <wenchaoqemu@gmail.com>2014-03-06 17:08:56 -0800
committerLuiz Capitulino <lcapitulino@redhat.com>2014-03-11 09:07:42 -0400
commitbceae7697ff1711675c26f715b945737bc6849ae (patch)
treeb528a35656db4d66e9c5be5be54edc7cbeb79344
parentb0b58195e4a3039b6a473124dc27ed707db50240 (diff)
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 <wenchaoqemu@gmail.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
-rw-r--r--docs/qapi-code-gen.txt8
-rw-r--r--scripts/qapi-types.py18
-rw-r--r--scripts/qapi-visit.py29
-rw-r--r--scripts/qapi.py27
-rw-r--r--tests/Makefile2
-rw-r--r--tests/qapi-schema/flat-union-reverse-define.err0
-rw-r--r--tests/qapi-schema/flat-union-reverse-define.exit1
-rw-r--r--tests/qapi-schema/flat-union-reverse-define.json17
-rw-r--r--tests/qapi-schema/flat-union-reverse-define.out9
9 files changed, 94 insertions, 17 deletions
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
--- /dev/null
+++ b/tests/qapi-schema/flat-union-reverse-define.err
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')]))])]