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1e6c1616a9
qemu/scripts/qapi-types.py
Markus Armbruster 1e6c1616a9 qapi: Generate a nicer struct for flat unions 
The struct generated for a flat union is weird: the members of its
base are at the end, except for the union tag, which is at the
beginning.

Example: qapi-schema-test.json has

    { 'struct': 'UserDefUnionBase',
      'data': { 'string': 'str', 'enum1': 'EnumOne' } }

    { 'union': 'UserDefFlatUnion',
      'base': 'UserDefUnionBase',
      'discriminator': 'enum1',
      'data': { 'value1' : 'UserDefA',
                'value2' : 'UserDefB',
                'value3' : 'UserDefB' } }

We generate:

    struct UserDefFlatUnion
    {
        EnumOne enum1;
        union {
            void *data;
            UserDefA *value1;
            UserDefB *value2;
            UserDefB *value3;
        };
        char *string;
    };

Change to put all base members at the beginning, unadulterated.  Not
only is this easier to understand, it also permits casting the flat
union to its base, if that should become useful.

We now generate:

    struct UserDefFlatUnion
    {
        /* Members inherited from UserDefUnionBase: */
        char *string;
        EnumOne enum1;
        /* Own members: */
        union { /* union tag is @enum1 */
            void *data;
            UserDefA *value1;
            UserDefB *value2;
            UserDefB *value3;
        };
    };

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
2015-09-04 15:47:13 +02:00

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#
# QAPI types generator
#
# Copyright IBM, Corp. 2011
#
# Authors:
# Anthony Liguori <aliguori@us.ibm.com>
#
# This work is licensed under the terms of the GNU GPL, version 2.
# See the COPYING file in the top-level directory.
from ordereddict import OrderedDict
from qapi import *
def generate_fwd_builtin(name):
return mcgen('''
typedef struct %(name)sList
{
union {
%(type)s value;
uint64_t padding;
};
struct %(name)sList *next;
} %(name)sList;
''',
type=c_type(name),
name=name)
def generate_fwd_struct(name):
return mcgen('''
typedef struct %(name)s %(name)s;
typedef struct %(name)sList
{
union {
%(name)s *value;
uint64_t padding;
};
struct %(name)sList *next;
} %(name)sList;
''',
name=c_name(name))
def generate_fwd_enum_struct(name):
return mcgen('''
typedef struct %(name)sList
{
union {
%(name)s value;
uint64_t padding;
};
struct %(name)sList *next;
} %(name)sList;
''',
name=c_name(name))
def generate_struct_fields(members):
ret = ''
for argname, argentry, optional in parse_args(members):
if optional:
ret += mcgen('''
bool has_%(c_name)s;
''',
c_name=c_name(argname))
ret += mcgen('''
%(c_type)s %(c_name)s;
''',
c_type=c_type(argentry), c_name=c_name(argname))
return ret
def generate_struct(expr):
structname = expr.get('struct', "")
members = expr['data']
base = expr.get('base')
ret = mcgen('''
struct %(name)s
{
''',
name=c_name(structname))
if base:
ret += generate_struct_fields({'base': base})
ret += generate_struct_fields(members)
# 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 not members:
ret += mcgen('''
char qapi_dummy_field_for_empty_struct;
''')
ret += mcgen('''
};
''')
return ret
def generate_enum_lookup(name, values):
ret = mcgen('''
const char * const %(name)s_lookup[] = {
''',
name=c_name(name))
for value in values:
index = c_enum_const(name, value)
ret += mcgen('''
[%(index)s] = "%(value)s",
''',
index = index, value = value)
max_index = c_enum_const(name, 'MAX')
ret += mcgen('''
[%(max_index)s] = NULL,
};
''',
max_index=max_index)
return ret
def generate_enum(name, values):
name = c_name(name)
lookup_decl = mcgen('''
extern const char * const %(name)s_lookup[];
''',
name=name)
enum_decl = mcgen('''
typedef enum %(name)s
{
''',
name=name)
# append automatically generated _MAX value
enum_values = values + [ 'MAX' ]
i = 0
for value in enum_values:
enum_full_value = c_enum_const(name, value)
enum_decl += mcgen('''
%(enum_full_value)s = %(i)d,
''',
enum_full_value = enum_full_value,
i=i)
i += 1
enum_decl += mcgen('''
} %(name)s;
''',
name=name)
return lookup_decl + enum_decl
def generate_alternate_qtypes(expr):
name = expr['alternate']
members = expr['data']
ret = mcgen('''
const int %(name)s_qtypes[QTYPE_MAX] = {
''',
name=c_name(name))
for key in members:
qtype = find_alternate_member_qtype(members[key])
assert qtype, "Invalid alternate member"
ret += mcgen('''
[%(qtype)s] = %(enum_const)s,
''',
qtype = qtype,
enum_const = c_enum_const(name + 'Kind', key))
ret += mcgen('''
};
''')
return ret
def generate_union(expr, meta):
name = c_name(expr[meta])
typeinfo = expr['data']
base = expr.get('base')
discriminator = expr.get('discriminator')
enum_define = discriminator_find_enum_define(expr)
if enum_define:
discriminator_type_name = enum_define['enum_name']
else:
discriminator_type_name = '%sKind' % (name)
ret = mcgen('''
struct %(name)s
{
''',
name=name)
if base:
ret += mcgen('''
/* Members inherited from %(c_name)s: */
''',
c_name=c_name(base))
base_fields = find_struct(base)['data']
ret += generate_struct_fields(base_fields)
ret += mcgen('''
/* Own members: */
''')
else:
assert not discriminator
ret += mcgen('''
%(discriminator_type_name)s kind;
''',
discriminator_type_name=c_name(discriminator_type_name))
ret += mcgen('''
union { /* union tag is @%(c_name)s */
void *data;
''',
c_name=c_name(discriminator or 'kind'))
for key in typeinfo:
ret += mcgen('''
%(c_type)s %(c_name)s;
''',
c_type=c_type(typeinfo[key]),
c_name=c_name(key))
ret += mcgen('''
};
};
''')
if meta == 'alternate':
ret += mcgen('''
extern const int %(name)s_qtypes[];
''',
name=name)
return ret
def generate_type_cleanup_decl(name):
ret = mcgen('''
void qapi_free_%(name)s(%(c_type)s obj);
''',
c_type=c_type(name), name=c_name(name))
return ret
def generate_type_cleanup(name):
ret = mcgen('''
void qapi_free_%(name)s(%(c_type)s obj)
{
QapiDeallocVisitor *md;
Visitor *v;
if (!obj) {
return;
}
md = qapi_dealloc_visitor_new();
v = qapi_dealloc_get_visitor(md);
visit_type_%(name)s(v, &obj, NULL, NULL);
qapi_dealloc_visitor_cleanup(md);
}
''',
c_type=c_type(name), name=c_name(name))
return ret
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 "qapi/dealloc-visitor.h"
#include "%(prefix)sqapi-types.h"
#include "%(prefix)sqapi-visit.h"
''',
prefix=prefix))
fdecl.write(mcgen('''
#include <stdbool.h>
#include <stdint.h>
'''))
exprs = parse_schema(input_file)
fdecl.write(guardstart("QAPI_TYPES_BUILTIN_STRUCT_DECL"))
for typename in builtin_types.keys():
fdecl.write(generate_fwd_builtin(typename))
fdecl.write(guardend("QAPI_TYPES_BUILTIN_STRUCT_DECL"))
for expr in exprs:
ret = "\n"
if expr.has_key('struct'):
ret += generate_fwd_struct(expr['struct'])
elif expr.has_key('enum'):
ret += generate_enum(expr['enum'], expr['data']) + "\n"
ret += generate_fwd_enum_struct(expr['enum'])
fdef.write(generate_enum_lookup(expr['enum'], expr['data']))
elif expr.has_key('union'):
ret += generate_fwd_struct(expr['union']) + "\n"
enum_define = discriminator_find_enum_define(expr)
if not enum_define:
ret += generate_enum('%sKind' % expr['union'], expr['data'].keys())
fdef.write(generate_enum_lookup('%sKind' % expr['union'],
expr['data'].keys()))
elif expr.has_key('alternate'):
ret += generate_fwd_struct(expr['alternate']) + "\n"
ret += generate_enum('%sKind' % expr['alternate'], expr['data'].keys())
fdef.write(generate_enum_lookup('%sKind' % expr['alternate'],
expr['data'].keys()))
fdef.write(generate_alternate_qtypes(expr))
else:
continue
fdecl.write(ret)
# to avoid header dependency hell, we always generate declarations
# for built-in types in our header files and simply guard them
fdecl.write(guardstart("QAPI_TYPES_BUILTIN_CLEANUP_DECL"))
for typename in builtin_types.keys():
fdecl.write(generate_type_cleanup_decl(typename + "List"))
fdecl.write(guardend("QAPI_TYPES_BUILTIN_CLEANUP_DECL"))
# ...this doesn't work for cases where we link in multiple objects that
# have the functions defined, so we use -b option to provide control
# over these cases
if do_builtins:
fdef.write(guardstart("QAPI_TYPES_BUILTIN_CLEANUP_DEF"))
for typename in builtin_types.keys():
fdef.write(generate_type_cleanup(typename + "List"))
fdef.write(guardend("QAPI_TYPES_BUILTIN_CLEANUP_DEF"))
for expr in exprs:
ret = "\n"
if expr.has_key('struct'):
ret += generate_struct(expr) + "\n"
ret += generate_type_cleanup_decl(expr['struct'] + "List")
fdef.write(generate_type_cleanup(expr['struct'] + "List") + "\n")
ret += generate_type_cleanup_decl(expr['struct'])
fdef.write(generate_type_cleanup(expr['struct']) + "\n")
elif expr.has_key('union'):
ret += generate_union(expr, 'union')
ret += generate_type_cleanup_decl(expr['union'] + "List")
fdef.write(generate_type_cleanup(expr['union'] + "List") + "\n")
ret += generate_type_cleanup_decl(expr['union'])
fdef.write(generate_type_cleanup(expr['union']) + "\n")
elif expr.has_key('alternate'):
ret += generate_union(expr, 'alternate')
ret += generate_type_cleanup_decl(expr['alternate'] + "List")
fdef.write(generate_type_cleanup(expr['alternate'] + "List") + "\n")
ret += generate_type_cleanup_decl(expr['alternate'])
fdef.write(generate_type_cleanup(expr['alternate']) + "\n")
elif expr.has_key('enum'):
ret += generate_type_cleanup_decl(expr['enum'] + "List")
fdef.write(generate_type_cleanup(expr['enum'] + "List") + "\n")
else:
continue
fdecl.write(ret)
close_output(fdef, fdecl)
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