Commit 570cd8d1 authored by Eric Blake's avatar Eric Blake Committed by Markus Armbruster
Browse files

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



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: default avatarEric Blake <eblake@redhat.com>
Message-Id: <1447836791-369-3-git-send-email-eblake@redhat.com>
Signed-off-by: default avatarMarkus Armbruster <armbru@redhat.com>
parent da34a9bd

scripts/qapi-types.py

+11 −26
Original line number Diff line number Diff line
@@ -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
@@ -159,7 +152,7 @@ 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;

''',
@@ -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)