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>
---
docs/qapi-code-gen.txt | 8 ++++++--
scripts/qapi-types.py | 20 ++++++++++++++++----
scripts/qapi-visit.py | 27 ++++++++++++++++++++-------
scripts/qapi.py | 13 ++++++++++++-
4 files changed, 54 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 656a9a0..4098c60 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -201,14 +201,22 @@ def generate_union(expr):
base = expr.get('base')
discriminator = expr.get('discriminator')
+ expr_elem = {'expr': expr}
+ enum_define = discriminator_find_enum_define(expr_elem)
+ 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 +397,12 @@ 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()))
+ expr_elem = {'expr': expr}
+ enum_define = discriminator_find_enum_define(expr_elem)
+ 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 87e6df7..08685a7 100644
--- a/scripts/qapi-visit.py
+++ b/scripts/qapi-visit.py
@@ -260,10 +260,17 @@ 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())
- discriminator_type_name = '%sKind' % (name)
+ expr_elem = {'expr': expr}
+ enum_define = discriminator_find_enum_define(expr_elem)
+ if enum_define:
+ # 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']
@@ -303,11 +310,12 @@ 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:
@@ -519,7 +527,12 @@ 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())
+ expr_elem = {'expr': expr}
+ enum_define = discriminator_find_enum_define(expr_elem)
+ 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 130dced..2a5eb59 100644
--- a/scripts/qapi.py
+++ b/scripts/qapi.py
@@ -250,11 +250,22 @@ 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'):
+ try:
+ enum_define = discriminator_find_enum_define(expr_elem)
+ except QAPIExprError, e:
+ print >>sys.stderr, e
+ exit(1)
+ if not enum_define:
+ add_enum('%sKind' % expr['union'])
+
try:
check_exprs(schema)
except QAPIExprError, e:
--
1.7.1
