qemu/scripts/qapi-types.py
Eric Blake 2c0ef9f411 qapi: Add new visit_free() function
Making each visitor provide its own (awkwardly-named) FOO_cleanup()
is unusual, when we can instead have a polymorphic visit_free()
interface.  Over the next few patches, we can use the polymorphic
functions to eliminate the need for a FOO_get_visitor() function
for accessing specific visitor functionality, once everything can
be accessed directly through the Visitor* interfaces.

The dealloc visitor is the first one converted to completely use
the new entry point, since qapi_dealloc_visitor_cleanup() was the
only reason that qapi_dealloc_get_visitor() existed, and only
generated and testsuite code was even using it.  With the new
visit_free() entry point in place, we no longer need to expose
the QapiDeallocVisitor subtype through qapi_dealloc_visitor_new(),
and can get by with less generated code, with diffs that look like:

| void qapi_free_ACPIOSTInfo(ACPIOSTInfo *obj)
| {
|-    QapiDeallocVisitor *qdv;
|     Visitor *v;
|
|     if (!obj) {
|         return;
|     }
|
|-    qdv = qapi_dealloc_visitor_new();
|-    v = qapi_dealloc_get_visitor(qdv);
|+    v = qapi_dealloc_visitor_new();
|     visit_type_ACPIOSTInfo(v, NULL, &obj, NULL);
|-    qapi_dealloc_visitor_cleanup(qdv);
|+    visit_free(v);
|}

Signed-off-by: Eric Blake <eblake@redhat.com>
Message-Id: <1465490926-28625-5-git-send-email-eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2016-07-06 10:52:04 +02:00

302 lines
8.0 KiB
Python

#
# QAPI types generator
#
# Copyright IBM, Corp. 2011
# Copyright (c) 2013-2016 Red Hat Inc.
#
# Authors:
# Anthony Liguori <aliguori@us.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 *
# variants must be emitted before their container; track what has already
# been output
objects_seen = set()
def gen_fwd_object_or_array(name):
return mcgen('''
typedef struct %(c_name)s %(c_name)s;
''',
c_name=c_name(name))
def gen_array(name, element_type):
return mcgen('''
struct %(c_name)s {
%(c_name)s *next;
%(c_type)s value;
};
''',
c_name=c_name(name), c_type=element_type.c_type())
def gen_struct_members(members):
ret = ''
for memb in members:
if memb.optional:
ret += mcgen('''
bool has_%(c_name)s;
''',
c_name=c_name(memb.name))
ret += mcgen('''
%(c_type)s %(c_name)s;
''',
c_type=memb.type.c_type(), c_name=c_name(memb.name))
return ret
def gen_object(name, base, members, variants):
if name in objects_seen:
return ''
objects_seen.add(name)
ret = ''
if variants:
for v in variants.variants:
if isinstance(v.type, QAPISchemaObjectType):
ret += gen_object(v.type.name, v.type.base,
v.type.local_members, v.type.variants)
ret += mcgen('''
struct %(c_name)s {
''',
c_name=c_name(name))
if base:
if not base.is_implicit():
ret += mcgen('''
/* Members inherited from %(c_name)s: */
''',
c_name=base.c_name())
ret += gen_struct_members(base.members)
if not base.is_implicit():
ret += mcgen('''
/* Own members: */
''')
ret += gen_struct_members(members)
if variants:
ret += gen_variants(variants)
# Make sure that all structs have at least one member; 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 and not variants:
ret += mcgen('''
char qapi_dummy_for_empty_struct;
''')
ret += mcgen('''
};
''')
return ret
def gen_upcast(name, base):
# C makes const-correctness ugly. We have to cast away const to let
# this function work for both const and non-const obj.
return mcgen('''
static inline %(base)s *qapi_%(c_name)s_base(const %(c_name)s *obj)
{
return (%(base)s *)obj;
}
''',
c_name=c_name(name), base=base.c_name())
def gen_variants(variants):
ret = mcgen('''
union { /* union tag is @%(c_name)s */
''',
c_name=c_name(variants.tag_member.name))
for var in variants.variants:
ret += mcgen('''
%(c_type)s %(c_name)s;
''',
c_type=var.type.c_unboxed_type(),
c_name=c_name(var.name))
ret += mcgen('''
} u;
''')
return ret
def gen_type_cleanup_decl(name):
ret = mcgen('''
void qapi_free_%(c_name)s(%(c_name)s *obj);
''',
c_name=c_name(name))
return ret
def gen_type_cleanup(name):
ret = mcgen('''
void qapi_free_%(c_name)s(%(c_name)s *obj)
{
Visitor *v;
if (!obj) {
return;
}
v = qapi_dealloc_visitor_new();
visit_type_%(c_name)s(v, NULL, &obj, NULL);
visit_free(v);
}
''',
c_name=c_name(name))
return ret
class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
def __init__(self):
self.decl = None
self.defn = None
self._fwdecl = None
self._btin = None
def visit_begin(self, schema):
# gen_object() is recursive, ensure it doesn't visit the empty type
objects_seen.add(schema.the_empty_object_type.name)
self.decl = ''
self.defn = ''
self._fwdecl = ''
self._btin = guardstart('QAPI_TYPES_BUILTIN')
def visit_end(self):
self.decl = self._fwdecl + self.decl
self._fwdecl = None
# 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_TYPES_BUILTIN')
self.decl = self._btin + self.decl
self._btin = None
def _gen_type_cleanup(self, name):
self.decl += gen_type_cleanup_decl(name)
self.defn += gen_type_cleanup(name)
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_enum(name, values, prefix)
if do_builtins:
self.defn += gen_enum_lookup(name, values, prefix)
else:
self._fwdecl += gen_enum(name, values, prefix)
self.defn += gen_enum_lookup(name, values, prefix)
def visit_array_type(self, name, info, element_type):
if isinstance(element_type, QAPISchemaBuiltinType):
self._btin += gen_fwd_object_or_array(name)
self._btin += gen_array(name, element_type)
self._btin += gen_type_cleanup_decl(name)
if do_builtins:
self.defn += gen_type_cleanup(name)
else:
self._fwdecl += gen_fwd_object_or_array(name)
self.decl += gen_array(name, element_type)
self._gen_type_cleanup(name)
def visit_object_type(self, name, info, base, members, variants):
# Nothing to do for the special empty builtin
if name == 'q_empty':
return
self._fwdecl += gen_fwd_object_or_array(name)
self.decl += gen_object(name, base, members, variants)
if base and not base.is_implicit():
self.decl += gen_upcast(name, base)
# TODO Worth changing the visitor signature, so we could
# directly use rather than repeat type.is_implicit()?
if not name.startswith('q_'):
# implicit types won't be directly allocated/freed
self._gen_type_cleanup(name)
def visit_alternate_type(self, name, info, variants):
self._fwdecl += gen_fwd_object_or_array(name)
self.decl += gen_object(name, None, [variants.tag_member], variants)
self._gen_type_cleanup(name)
# 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
# QAPISchemaGenTypeVisitor.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 = '''
/*
* deallocation functions for schema-defined QAPI types
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
* Michael Roth <mdroth@linux.vnet.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 types
*
* 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-types.c', 'qapi-types.h',
c_comment, h_comment)
fdef.write(mcgen('''
#include "qemu/osdep.h"
#include "qapi/dealloc-visitor.h"
#include "%(prefix)sqapi-types.h"
#include "%(prefix)sqapi-visit.h"
''',
prefix=prefix))
schema = QAPISchema(input_file)
gen = QAPISchemaGenTypeVisitor()
schema.visit(gen)
fdef.write(gen.defn)
fdecl.write(gen.decl)
close_output(fdef, fdecl)