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7ce106a96f
We already have several places that want to visit all the members
of an implicit object within a larger context (simple union variant,
event with anonymous data, command with anonymous arguments struct);
and will be adding another one soon (the ability to declare an
anonymous base for a flat union). Having a C struct declared for
these implicit types, along with a visit_type_FOO_members() helper
function, will make for fewer special cases in our generator.
We do not, however, need qapi_free_FOO() or visit_type_FOO()
functions for implicit types, because they should not be used
directly outside of the generated code. This is done by adding a
conditional in visit_object_type() for both qapi-types.py and
qapi-visit.py based on the object name. The comparison of
"name.startswith('q_')" is a bit hacky (it's basically duplicating
what .is_implicit() already uses), but beats changing the signature
of the visit_object_type() callback to pass a new 'implicit' flag.
The hack should be temporary: we are considering adding a future
patch that consolidates the narrow visit_object_type(..., base,
local_members, variants) and visit_object_type_flat(...,
all_members, variants) [where different sets of information are
already broken out, and the QAPISchemaObjectType is no longer
available] into a broader visit_object_type(obj_type) [where the
visitor can query the needed fields from obj_type directly].
Also, now that we WANT to output C code for implicits, we no longer
need the visit_needed() filter, leaving 'q_empty' as the only object
still needing a special case. Remember, 'q_empty' is the only
built-in generated object, which means that without a special case
it would be emitted in multiple files (the main qapi-types.h and in
qga-qapi-types.h) causing compilation failure due to redefinition.
But since it has no members, it's easier to just avoid an attempt to
visit that particular type; since gen_object() is called recursively,
we also prime the objects_seen set to cover any recursion into the
empty type.
The patch relies on the changed naming of implicit types in the
previous patch. It is a bit unfortunate that the generated struct
names and visit_type_FOO_members() don't match normal naming
conventions, but it's not too bad, since they will only be used in
generated code.
The generated code grows substantially in size: the implicit
'-wrapper' types must be emitted in qapi-types.h before any union
can include an unboxed member of that type. Arguably, the '-args'
types could be emitted in a private header for just qapi-visit.c
and qmp-marshal.c, rather than polluting qapi-types.h; but adding
complexity to the generator to split the output location according
to role doesn't seem worth the maintenance costs.
Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1458254921-17042-6-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
373 lines
10 KiB
Python
373 lines
10 KiB
Python
#
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# QAPI visitor generator
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#
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# Copyright IBM, Corp. 2011
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# Copyright (C) 2014-2016 Red Hat, Inc.
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#
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# Authors:
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# Anthony Liguori <aliguori@us.ibm.com>
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# Michael Roth <mdroth@linux.vnet.ibm.com>
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# Markus Armbruster <armbru@redhat.com>
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#
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# This work is licensed under the terms of the GNU GPL, version 2.
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# See the COPYING file in the top-level directory.
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from qapi import *
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import re
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def gen_visit_decl(name, scalar=False):
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c_type = c_name(name) + ' *'
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if not scalar:
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c_type += '*'
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return mcgen('''
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void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_type)sobj, Error **errp);
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''',
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c_name=c_name(name), c_type=c_type)
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def gen_visit_members_decl(name):
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return mcgen('''
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void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp);
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''',
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c_name=c_name(name))
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def gen_visit_object_members(name, base, members, variants):
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ret = mcgen('''
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void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
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{
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Error *err = NULL;
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''',
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c_name=c_name(name))
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if base:
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ret += mcgen('''
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visit_type_%(c_type)s_members(v, (%(c_type)s *)obj, &err);
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''',
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c_type=base.c_name())
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ret += gen_err_check()
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ret += gen_visit_members(members, prefix='obj->')
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if variants:
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ret += mcgen('''
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switch (obj->%(c_name)s) {
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''',
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c_name=c_name(variants.tag_member.name))
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for var in variants.variants:
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# TODO ugly special case for simple union
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simple_union_type = var.simple_union_type()
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ret += mcgen('''
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case %(case)s:
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''',
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case=c_enum_const(variants.tag_member.type.name,
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var.name,
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variants.tag_member.type.prefix))
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if simple_union_type:
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ret += mcgen('''
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visit_type_%(c_type)s(v, "data", &obj->u.%(c_name)s, &err);
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''',
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c_type=simple_union_type.c_name(),
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c_name=c_name(var.name))
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else:
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ret += mcgen('''
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visit_type_%(c_type)s_members(v, &obj->u.%(c_name)s, &err);
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''',
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c_type=var.type.c_name(),
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c_name=c_name(var.name))
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ret += mcgen('''
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break;
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''')
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ret += mcgen('''
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default:
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abort();
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}
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''')
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# 'goto out' produced for base, by gen_visit_members() for each member,
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# and if variants were present
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if base or members or variants:
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ret += mcgen('''
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out:
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''')
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ret += mcgen('''
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error_propagate(errp, err);
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}
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''')
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return ret
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def gen_visit_list(name, element_type):
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# FIXME: if *obj is NULL on entry, and the first visit_next_list()
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# assigns to *obj, while a later one fails, we should clean up *obj
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# rather than leaving it non-NULL. As currently written, the caller must
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# call qapi_free_FOOList() to avoid a memory leak of the partial FOOList.
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return mcgen('''
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void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
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{
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Error *err = NULL;
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GenericList *i, **prev;
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visit_start_list(v, name, &err);
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if (err) {
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goto out;
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}
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for (prev = (GenericList **)obj;
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!err && (i = visit_next_list(v, prev, sizeof(**obj))) != NULL;
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prev = &i) {
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%(c_name)s *native_i = (%(c_name)s *)i;
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visit_type_%(c_elt_type)s(v, NULL, &native_i->value, &err);
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}
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visit_end_list(v);
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out:
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error_propagate(errp, err);
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}
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''',
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c_name=c_name(name), c_elt_type=element_type.c_name())
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def gen_visit_enum(name):
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return mcgen('''
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void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s *obj, Error **errp)
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{
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int value = *obj;
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visit_type_enum(v, name, &value, %(c_name)s_lookup, errp);
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*obj = value;
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}
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''',
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c_name=c_name(name))
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def gen_visit_alternate(name, variants):
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promote_int = 'true'
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ret = ''
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for var in variants.variants:
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if var.type.alternate_qtype() == 'QTYPE_QINT':
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promote_int = 'false'
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ret += mcgen('''
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void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
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{
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Error *err = NULL;
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visit_start_alternate(v, name, (GenericAlternate **)obj, sizeof(**obj),
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%(promote_int)s, &err);
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if (err) {
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goto out;
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}
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switch ((*obj)->type) {
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''',
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c_name=c_name(name), promote_int=promote_int)
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for var in variants.variants:
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ret += mcgen('''
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case %(case)s:
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''',
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case=var.type.alternate_qtype())
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if isinstance(var.type, QAPISchemaObjectType):
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ret += mcgen('''
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visit_start_struct(v, name, NULL, 0, &err);
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if (err) {
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break;
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}
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visit_type_%(c_type)s_members(v, &(*obj)->u.%(c_name)s, &err);
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error_propagate(errp, err);
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err = NULL;
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visit_end_struct(v, &err);
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''',
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c_type=var.type.c_name(),
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c_name=c_name(var.name))
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else:
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ret += mcgen('''
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visit_type_%(c_type)s(v, name, &(*obj)->u.%(c_name)s, &err);
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''',
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c_type=var.type.c_name(),
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c_name=c_name(var.name))
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ret += mcgen('''
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break;
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''')
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ret += mcgen('''
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default:
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error_setg(&err, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
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"%(name)s");
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}
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visit_end_alternate(v);
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out:
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error_propagate(errp, err);
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}
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''',
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name=name)
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return ret
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def gen_visit_object(name, base, members, variants):
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# FIXME: if *obj is NULL on entry, and visit_start_struct() assigns to
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# *obj, but then visit_type_FOO_members() fails, we should clean up *obj
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# rather than leaving it non-NULL. As currently written, the caller must
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# call qapi_free_FOO() to avoid a memory leak of the partial FOO.
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return mcgen('''
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void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
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{
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Error *err = NULL;
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visit_start_struct(v, name, (void **)obj, sizeof(%(c_name)s), &err);
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if (err) {
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goto out;
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}
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if (!*obj) {
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goto out_obj;
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}
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visit_type_%(c_name)s_members(v, *obj, &err);
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error_propagate(errp, err);
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err = NULL;
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out_obj:
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visit_end_struct(v, &err);
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out:
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error_propagate(errp, err);
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}
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''',
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c_name=c_name(name))
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class QAPISchemaGenVisitVisitor(QAPISchemaVisitor):
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def __init__(self):
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self.decl = None
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self.defn = None
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self._btin = None
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def visit_begin(self, schema):
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self.decl = ''
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self.defn = ''
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self._btin = guardstart('QAPI_VISIT_BUILTIN')
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def visit_end(self):
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# To avoid header dependency hell, we always generate
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# declarations for built-in types in our header files and
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# simply guard them. See also do_builtins (command line
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# option -b).
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self._btin += guardend('QAPI_VISIT_BUILTIN')
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self.decl = self._btin + self.decl
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self._btin = None
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def visit_enum_type(self, name, info, values, prefix):
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# Special case for our lone builtin enum type
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# TODO use something cleaner than existence of info
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if not info:
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self._btin += gen_visit_decl(name, scalar=True)
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if do_builtins:
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self.defn += gen_visit_enum(name)
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else:
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self.decl += gen_visit_decl(name, scalar=True)
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self.defn += gen_visit_enum(name)
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def visit_array_type(self, name, info, element_type):
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decl = gen_visit_decl(name)
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defn = gen_visit_list(name, element_type)
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if isinstance(element_type, QAPISchemaBuiltinType):
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self._btin += decl
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if do_builtins:
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self.defn += defn
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else:
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self.decl += decl
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self.defn += defn
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def visit_object_type(self, name, info, base, members, variants):
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# Nothing to do for the special empty builtin
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if name == 'q_empty':
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return
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self.decl += gen_visit_members_decl(name)
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self.defn += gen_visit_object_members(name, base, members, variants)
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# TODO Worth changing the visitor signature, so we could
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# directly use rather than repeat type.is_implicit()?
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if not name.startswith('q_'):
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# only explicit types need an allocating visit
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self.decl += gen_visit_decl(name)
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self.defn += gen_visit_object(name, base, members, variants)
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def visit_alternate_type(self, name, info, variants):
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self.decl += gen_visit_decl(name)
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self.defn += gen_visit_alternate(name, variants)
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# If you link code generated from multiple schemata, you want only one
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# instance of the code for built-in types. Generate it only when
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# do_builtins, enabled by command line option -b. See also
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# QAPISchemaGenVisitVisitor.visit_end().
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do_builtins = False
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(input_file, output_dir, do_c, do_h, prefix, opts) = \
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parse_command_line("b", ["builtins"])
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for o, a in opts:
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if o in ("-b", "--builtins"):
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do_builtins = True
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c_comment = '''
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/*
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* schema-defined QAPI visitor functions
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*
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* Copyright IBM, Corp. 2011
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
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* See the COPYING.LIB file in the top-level directory.
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*
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*/
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'''
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h_comment = '''
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/*
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* schema-defined QAPI visitor functions
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*
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* Copyright IBM, Corp. 2011
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
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* See the COPYING.LIB file in the top-level directory.
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*
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*/
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'''
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(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
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'qapi-visit.c', 'qapi-visit.h',
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c_comment, h_comment)
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fdef.write(mcgen('''
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#include "qemu/osdep.h"
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#include "qemu-common.h"
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#include "%(prefix)sqapi-visit.h"
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''',
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prefix=prefix))
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fdecl.write(mcgen('''
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#include "qapi/visitor.h"
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#include "qapi/qmp/qerror.h"
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#include "%(prefix)sqapi-types.h"
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''',
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prefix=prefix))
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schema = QAPISchema(input_file)
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gen = QAPISchemaGenVisitVisitor()
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schema.visit(gen)
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fdef.write(gen.defn)
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fdecl.write(gen.decl)
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close_output(fdef, fdecl)
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