qemu-patch-raspberry4/scripts/qapi-visit.py
Eric Blake 4d91e9115c qapi-visit: Expose visit_type_FOO_members()
Dan Berrange reported a case where he needs to work with a
QCryptoBlockOptions union type using the OptsVisitor, but only
visit one of the branches of that type (the discriminator is not
visited directly, but learned externally).  When things were
boxed, it was easy: just visit the variant directly, which took
care of both allocating the variant and visiting its members, then
store that pointer in the union type.  But now that things are
unboxed, we need a way to visit the members without allocation,
done by exposing visit_type_FOO_members() to the user.

Before the patch, we had quite a bit of code associated with
object_members_seen to make sure that a declaration of the helper
was in scope before any use of the function.  But now that the
helper is public and declared in the header, the .c file no
longer needs to worry about topological sorting (the helper is
always in scope), which leads to some nice cleanups.

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1457021813-10704-4-git-send-email-eblake@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-03-05 10:41:13 +01:00

375 lines
10 KiB
Python

#
# QAPI visitor generator
#
# Copyright IBM, Corp. 2011
# Copyright (C) 2014-2016 Red Hat, Inc.
#
# Authors:
# Anthony Liguori <aliguori@us.ibm.com>
# Michael Roth <mdroth@linux.vnet.ibm.com>
# Markus Armbruster <armbru@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2.
# See the COPYING file in the top-level directory.
from qapi import *
import re
def gen_visit_decl(name, scalar=False):
c_type = c_name(name) + ' *'
if not scalar:
c_type += '*'
return mcgen('''
void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_type)sobj, Error **errp);
''',
c_name=c_name(name), c_type=c_type)
def gen_visit_members_decl(name):
return mcgen('''
void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp);
''',
c_name=c_name(name))
def gen_visit_object_members(name, base, members, variants):
ret = mcgen('''
void visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
{
Error *err = NULL;
''',
c_name=c_name(name))
if base:
ret += mcgen('''
visit_type_%(c_type)s_members(v, (%(c_type)s *)obj, &err);
''',
c_type=base.c_name())
ret += gen_err_check()
ret += gen_visit_members(members, prefix='obj->')
if variants:
ret += mcgen('''
switch (obj->%(c_name)s) {
''',
c_name=c_name(variants.tag_member.name))
for var in variants.variants:
# TODO ugly special case for simple union
simple_union_type = var.simple_union_type()
ret += mcgen('''
case %(case)s:
''',
case=c_enum_const(variants.tag_member.type.name,
var.name,
variants.tag_member.type.prefix))
if simple_union_type:
ret += mcgen('''
visit_type_%(c_type)s(v, "data", &obj->u.%(c_name)s, &err);
''',
c_type=simple_union_type.c_name(),
c_name=c_name(var.name))
else:
ret += mcgen('''
visit_type_%(c_type)s_members(v, &obj->u.%(c_name)s, &err);
''',
c_type=var.type.c_name(),
c_name=c_name(var.name))
ret += mcgen('''
break;
''')
ret += mcgen('''
default:
abort();
}
''')
# 'goto out' produced for base, by gen_visit_members() for each member,
# and if variants were present
if base or members or variants:
ret += mcgen('''
out:
''')
ret += mcgen('''
error_propagate(errp, err);
}
''')
return ret
def gen_visit_list(name, element_type):
# FIXME: if *obj is NULL on entry, and the first visit_next_list()
# assigns to *obj, while a later one fails, we should clean up *obj
# rather than leaving it non-NULL. As currently written, the caller must
# call qapi_free_FOOList() to avoid a memory leak of the partial FOOList.
return mcgen('''
void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
{
Error *err = NULL;
GenericList *i, **prev;
visit_start_list(v, name, &err);
if (err) {
goto out;
}
for (prev = (GenericList **)obj;
!err && (i = visit_next_list(v, prev, sizeof(**obj))) != NULL;
prev = &i) {
%(c_name)s *native_i = (%(c_name)s *)i;
visit_type_%(c_elt_type)s(v, NULL, &native_i->value, &err);
}
visit_end_list(v);
out:
error_propagate(errp, err);
}
''',
c_name=c_name(name), c_elt_type=element_type.c_name())
def gen_visit_enum(name):
return mcgen('''
void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s *obj, Error **errp)
{
int value = *obj;
visit_type_enum(v, name, &value, %(c_name)s_lookup, errp);
*obj = value;
}
''',
c_name=c_name(name))
def gen_visit_alternate(name, variants):
promote_int = 'true'
ret = ''
for var in variants.variants:
if var.type.alternate_qtype() == 'QTYPE_QINT':
promote_int = 'false'
ret += mcgen('''
void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
{
Error *err = NULL;
visit_start_alternate(v, name, (GenericAlternate **)obj, sizeof(**obj),
%(promote_int)s, &err);
if (err) {
goto out;
}
switch ((*obj)->type) {
''',
c_name=c_name(name), promote_int=promote_int)
for var in variants.variants:
ret += mcgen('''
case %(case)s:
''',
case=var.type.alternate_qtype())
if isinstance(var.type, QAPISchemaObjectType):
ret += mcgen('''
visit_start_struct(v, name, NULL, 0, &err);
if (err) {
break;
}
visit_type_%(c_type)s_members(v, &(*obj)->u.%(c_name)s, &err);
error_propagate(errp, err);
err = NULL;
visit_end_struct(v, &err);
''',
c_type=var.type.c_name(),
c_name=c_name(var.name))
else:
ret += mcgen('''
visit_type_%(c_type)s(v, name, &(*obj)->u.%(c_name)s, &err);
''',
c_type=var.type.c_name(),
c_name=c_name(var.name))
ret += mcgen('''
break;
''')
ret += mcgen('''
default:
error_setg(&err, QERR_INVALID_PARAMETER_TYPE, name ? name : "null",
"%(name)s");
}
visit_end_alternate(v);
out:
error_propagate(errp, err);
}
''',
name=name)
return ret
def gen_visit_object(name, base, members, variants):
ret = gen_visit_object_members(name, base, members, variants)
# FIXME: if *obj is NULL on entry, and visit_start_struct() assigns to
# *obj, but then visit_type_FOO_members() fails, we should clean up *obj
# rather than leaving it non-NULL. As currently written, the caller must
# call qapi_free_FOO() to avoid a memory leak of the partial FOO.
ret += mcgen('''
void visit_type_%(c_name)s(Visitor *v, const char *name, %(c_name)s **obj, Error **errp)
{
Error *err = NULL;
visit_start_struct(v, name, (void **)obj, sizeof(%(c_name)s), &err);
if (err) {
goto out;
}
if (!*obj) {
goto out_obj;
}
visit_type_%(c_name)s_members(v, *obj, &err);
error_propagate(errp, err);
err = NULL;
out_obj:
visit_end_struct(v, &err);
out:
error_propagate(errp, err);
}
''',
c_name=c_name(name))
return ret
class QAPISchemaGenVisitVisitor(QAPISchemaVisitor):
def __init__(self):
self.decl = None
self.defn = None
self._btin = None
def visit_begin(self, schema):
self.decl = ''
self.defn = ''
self._btin = guardstart('QAPI_VISIT_BUILTIN')
def visit_end(self):
# To avoid header dependency hell, we always generate
# declarations for built-in types in our header files and
# simply guard them. See also do_builtins (command line
# option -b).
self._btin += guardend('QAPI_VISIT_BUILTIN')
self.decl = self._btin + self.decl
self._btin = None
def visit_needed(self, entity):
# Visit everything except implicit objects
return not (entity.is_implicit() and
isinstance(entity, QAPISchemaObjectType))
def visit_enum_type(self, name, info, values, prefix):
# Special case for our lone builtin enum type
# TODO use something cleaner than existence of info
if not info:
self._btin += gen_visit_decl(name, scalar=True)
if do_builtins:
self.defn += gen_visit_enum(name)
else:
self.decl += gen_visit_decl(name, scalar=True)
self.defn += gen_visit_enum(name)
def visit_array_type(self, name, info, element_type):
decl = gen_visit_decl(name)
defn = gen_visit_list(name, element_type)
if isinstance(element_type, QAPISchemaBuiltinType):
self._btin += decl
if do_builtins:
self.defn += defn
else:
self.decl += decl
self.defn += defn
def visit_object_type(self, name, info, base, members, variants):
self.decl += gen_visit_members_decl(name)
self.decl += gen_visit_decl(name)
self.defn += gen_visit_object(name, base, members, variants)
def visit_alternate_type(self, name, info, variants):
self.decl += gen_visit_decl(name)
self.defn += gen_visit_alternate(name, variants)
# If you link code generated from multiple schemata, you want only one
# instance of the code for built-in types. Generate it only when
# do_builtins, enabled by command line option -b. See also
# QAPISchemaGenVisitVisitor.visit_end().
do_builtins = False
(input_file, output_dir, do_c, do_h, prefix, opts) = \
parse_command_line("b", ["builtins"])
for o, a in opts:
if o in ("-b", "--builtins"):
do_builtins = True
c_comment = '''
/*
* schema-defined QAPI visitor functions
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
'''
h_comment = '''
/*
* schema-defined QAPI visitor functions
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
'''
(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
'qapi-visit.c', 'qapi-visit.h',
c_comment, h_comment)
fdef.write(mcgen('''
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "%(prefix)sqapi-visit.h"
''',
prefix=prefix))
fdecl.write(mcgen('''
#include "qapi/visitor.h"
#include "qapi/qmp/qerror.h"
#include "%(prefix)sqapi-types.h"
''',
prefix=prefix))
schema = QAPISchema(input_file)
gen = QAPISchemaGenVisitVisitor()
schema.visit(gen)
fdef.write(gen.defn)
fdecl.write(gen.decl)
close_output(fdef, fdecl)