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qapi-types: Consolidate gen_struct() and gen_union()

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These two methods are now close enough that we can finally merge
them, relying on the fact that simple unions now provide a
reasonable local_members.  Change gen_struct() to gen_object()
that handles all forms of QAPISchemaObjectType, and rename and
shrink gen_union() to gen_variants() to handle the portion of
gen_object() needed when variants are present.

gen_struct_fields() now has a single caller, so it no longer
needs an optional parameter; however, I did not choose to inline
it into the caller.

No difference to generated code.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1447836791-369-3-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This commit is contained in:
Eric Blake 2015-11-18 01:52:37 -07:00 committed by Markus Armbruster
parent da34a9bd99
commit 570cd8d119
1 changed files with 11 additions and 26 deletions
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37
scripts/qapi-types.py
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@ -51,7 +51,7 @@ def gen_struct_field(member):
return ret
def gen_struct_fields(local_members, base=None):
def gen_struct_fields(local_members, base):
ret = ''
if base:
@ -70,7 +70,7 @@ def gen_struct_fields(local_members, base=None):
return ret
def gen_struct(name, base, members):
def gen_object(name, base, members, variants):
ret = mcgen('''
struct %(c_name)s {
@ -79,11 +79,14 @@ struct %(c_name)s {
ret += gen_struct_fields(members, base)
if variants:
ret += gen_variants(variants)
# Make sure that all structs have at least one field; this avoids
# potential issues with attempting to malloc space for zero-length
# structs in C, and also incompatibility with C++ (where an empty
# struct is size 1).
if not (base and base.members) and not members:
if not (base and base.members) and not members and not variants:
ret += mcgen('''
char qapi_dummy_field_for_empty_struct;
''')
@ -140,17 +143,7 @@ const int %(c_name)s_qtypes[QTYPE_MAX] = {
return ret
def gen_union(name, base, variants):
ret = mcgen('''
struct %(c_name)s {
''',
c_name=c_name(name))
if base:
ret += gen_struct_fields([], base)
else:
ret += gen_struct_field(variants.tag_member)
def gen_variants(variants):
# FIXME: What purpose does data serve, besides preventing a union that
# has a branch named 'data'? We use it in qapi-visit.py to decide
# whether to bypass the switch statement if visiting the discriminator
@ -159,11 +152,11 @@ struct %(c_name)s {
# should not be any data leaks even without a data pointer. Or, if
# 'data' is merely added to guarantee we don't have an empty union,
# shouldn't we enforce that at .json parse time?
ret += mcgen('''
ret = mcgen('''
union { /* union tag is @%(c_name)s */
void *data;
''',
c_name=c_name(variants.tag_member.name))
c_name=c_name(variants.tag_member.name))
for var in variants.variants:
# Ugly special case for simple union TODO get rid of it
@ -176,7 +169,6 @@ struct %(c_name)s {
ret += mcgen('''
} u;
};
''')
return ret
@ -268,14 +260,7 @@ class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
def visit_object_type(self, name, info, base, members, variants):
self._fwdecl += gen_fwd_object_or_array(name)
if variants:
if members:
# Members other than variants.tag_member not implemented
assert len(members) == 1
assert members[0] == variants.tag_member
self.decl += gen_union(name, base, variants)
else:
self.decl += gen_struct(name, base, members)
self.decl += gen_object(name, base, members, variants)
if base:
self.decl += gen_upcast(name, base)
self._gen_type_cleanup(name)
@ -283,7 +268,7 @@ class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
def visit_alternate_type(self, name, info, variants):
self._fwdecl += gen_fwd_object_or_array(name)
self._fwdefn += gen_alternate_qtypes(name, variants)
self.decl += gen_union(name, None, variants)
self.decl += gen_object(name, None, [variants.tag_member], variants)
self.decl += gen_alternate_qtypes_decl(name)
self._gen_type_cleanup(name)