scripts/qapi-types.py

   1 #
   2 # QAPI types generator
   3 #
   4 # Copyright IBM, Corp. 2011
   5 # Copyright (c) 2013-2015 Red Hat Inc.
   6 #
   7 # Authors:
   8 #  Anthony Liguori <aliguori@us.ibm.com>
   9 #  Markus Armbruster <armbru@redhat.com>
  10 #
  11 # This work is licensed under the terms of the GNU GPL, version 2.
  12 # See the COPYING file in the top-level directory.
  13
  14 from qapi import *
  15
  16
  17 def gen_fwd_object_or_array(name):
  18     return mcgen('''
  19
  20 typedef struct %(c_name)s %(c_name)s;
  21 ''',
  22                  c_name=c_name(name))
  23
  24
  25 def gen_array(name, element_type):
  26     return mcgen('''
  27
  28 struct %(c_name)s {
  29     union {
  30         %(c_type)s value;
  31         uint64_t padding;
  32     };
  33     %(c_name)s *next;
  34 };
  35 ''',
  36                  c_name=c_name(name), c_type=element_type.c_type())
  37
  38
  39 def gen_struct_fields(members):
  40     ret = ''
  41     for memb in members:
  42         if memb.optional:
  43             ret += mcgen('''
  44     bool has_%(c_name)s;
  45 ''',
  46                          c_name=c_name(memb.name))
  47         ret += mcgen('''
  48     %(c_type)s %(c_name)s;
  49 ''',
  50                      c_type=memb.type.c_type(), c_name=c_name(memb.name))
  51     return ret
  52
  53
  54 def gen_object(name, base, members, variants):
  55     ret = mcgen('''
  56
  57 struct %(c_name)s {
  58 ''',
  59                 c_name=c_name(name))
  60
  61     if base:
  62         ret += mcgen('''
  63     /* Members inherited from %(c_name)s: */
  64 ''',
  65                      c_name=base.c_name())
  66         ret += gen_struct_fields(base.members)
  67         ret += mcgen('''
  68     /* Own members: */
  69 ''')
  70     ret += gen_struct_fields(members)
  71
  72     if variants:
  73         ret += gen_variants(variants)
  74
  75     # Make sure that all structs have at least one field; this avoids
  76     # potential issues with attempting to malloc space for zero-length
  77     # structs in C, and also incompatibility with C++ (where an empty
  78     # struct is size 1).
  79     if not (base and base.members) and not members and not variants:
  80         ret += mcgen('''
  81     char qapi_dummy_field_for_empty_struct;
  82 ''')
  83
  84     ret += mcgen('''
  85 };
  86 ''')
  87
  88     return ret
  89
  90
  91 def gen_upcast(name, base):
  92     # C makes const-correctness ugly.  We have to cast away const to let
  93     # this function work for both const and non-const obj.
  94     return mcgen('''
  95
  96 static inline %(base)s *qapi_%(c_name)s_base(const %(c_name)s *obj)
  97 {
  98     return (%(base)s *)obj;
  99 }
 100 ''',
 101                  c_name=c_name(name), base=base.c_name())
 102
 103
 104 def gen_variants(variants):
 105     # FIXME: What purpose does data serve, besides preventing a union that
 106     # has a branch named 'data'? We use it in qapi-visit.py to decide
 107     # whether to bypass the switch statement if visiting the discriminator
 108     # failed; but since we 0-initialize structs, and cannot tell what
 109     # branch of the union is in use if the discriminator is invalid, there
 110     # should not be any data leaks even without a data pointer.  Or, if
 111     # 'data' is merely added to guarantee we don't have an empty union,
 112     # shouldn't we enforce that at .json parse time?
 113     ret = mcgen('''
 114     union { /* union tag is @%(c_name)s */
 115         void *data;
 116 ''',
 117                 c_name=c_name(variants.tag_member.name))
 118
 119     for var in variants.variants:
 120         # Ugly special case for simple union TODO get rid of it
 121         typ = var.simple_union_type() or var.type
 122         ret += mcgen('''
 123         %(c_type)s %(c_name)s;
 124 ''',
 125                      c_type=typ.c_type(),
 126                      c_name=c_name(var.name))
 127
 128     ret += mcgen('''
 129     } u;
 130 ''')
 131
 132     return ret
 133
 134
 135 def gen_type_cleanup_decl(name):
 136     ret = mcgen('''
 137
 138 void qapi_free_%(c_name)s(%(c_name)s *obj);
 139 ''',
 140                 c_name=c_name(name))
 141     return ret
 142
 143
 144 def gen_type_cleanup(name):
 145     ret = mcgen('''
 146
 147 void qapi_free_%(c_name)s(%(c_name)s *obj)
 148 {
 149     QapiDeallocVisitor *qdv;
 150     Visitor *v;
 151
 152     if (!obj) {
 153         return;
 154     }
 155
 156     qdv = qapi_dealloc_visitor_new();
 157     v = qapi_dealloc_get_visitor(qdv);
 158     visit_type_%(c_name)s(v, NULL, &obj, NULL);
 159     qapi_dealloc_visitor_cleanup(qdv);
 160 }
 161 ''',
 162                 c_name=c_name(name))
 163     return ret
 164
 165
 166 class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
 167     def __init__(self):
 168         self.decl = None
 169         self.defn = None
 170         self._fwdecl = None
 171         self._btin = None
 172
 173     def visit_begin(self, schema):
 174         self.decl = ''
 175         self.defn = ''
 176         self._fwdecl = ''
 177         self._btin = guardstart('QAPI_TYPES_BUILTIN')
 178
 179     def visit_end(self):
 180         self.decl = self._fwdecl + self.decl
 181         self._fwdecl = None
 182         # To avoid header dependency hell, we always generate
 183         # declarations for built-in types in our header files and
 184         # simply guard them.  See also do_builtins (command line
 185         # option -b).
 186         self._btin += guardend('QAPI_TYPES_BUILTIN')
 187         self.decl = self._btin + self.decl
 188         self._btin = None
 189
 190     def visit_needed(self, entity):
 191         # Visit everything except implicit objects
 192         return not (entity.is_implicit() and
 193                     isinstance(entity, QAPISchemaObjectType))
 194
 195     def _gen_type_cleanup(self, name):
 196         self.decl += gen_type_cleanup_decl(name)
 197         self.defn += gen_type_cleanup(name)
 198
 199     def visit_enum_type(self, name, info, values, prefix):
 200         # Special case for our lone builtin enum type
 201         # TODO use something cleaner than existence of info
 202         if not info:
 203             self._btin += gen_enum(name, values, prefix)
 204             if do_builtins:
 205                 self.defn += gen_enum_lookup(name, values, prefix)
 206         else:
 207             self._fwdecl += gen_enum(name, values, prefix)
 208             self.defn += gen_enum_lookup(name, values, prefix)
 209
 210     def visit_array_type(self, name, info, element_type):
 211         if isinstance(element_type, QAPISchemaBuiltinType):
 212             self._btin += gen_fwd_object_or_array(name)
 213             self._btin += gen_array(name, element_type)
 214             self._btin += gen_type_cleanup_decl(name)
 215             if do_builtins:
 216                 self.defn += gen_type_cleanup(name)
 217         else:
 218             self._fwdecl += gen_fwd_object_or_array(name)
 219             self.decl += gen_array(name, element_type)
 220             self._gen_type_cleanup(name)
 221
 222     def visit_object_type(self, name, info, base, members, variants):
 223         self._fwdecl += gen_fwd_object_or_array(name)
 224         self.decl += gen_object(name, base, members, variants)
 225         if base:
 226             self.decl += gen_upcast(name, base)
 227         self._gen_type_cleanup(name)
 228
 229     def visit_alternate_type(self, name, info, variants):
 230         self._fwdecl += gen_fwd_object_or_array(name)
 231         self.decl += gen_object(name, None, [variants.tag_member], variants)
 232         self._gen_type_cleanup(name)
 233
 234 # If you link code generated from multiple schemata, you want only one
 235 # instance of the code for built-in types.  Generate it only when
 236 # do_builtins, enabled by command line option -b.  See also
 237 # QAPISchemaGenTypeVisitor.visit_end().
 238 do_builtins = False
 239
 240 (input_file, output_dir, do_c, do_h, prefix, opts) = \
 241     parse_command_line("b", ["builtins"])
 242
 243 for o, a in opts:
 244     if o in ("-b", "--builtins"):
 245         do_builtins = True
 246
 247 c_comment = '''
 248 /*
 249  * deallocation functions for schema-defined QAPI types
 250  *
 251  * Copyright IBM, Corp. 2011
 252  *
 253  * Authors:
 254  *  Anthony Liguori   <aliguori@us.ibm.com>
 255  *  Michael Roth      <mdroth@linux.vnet.ibm.com>
 256  *
 257  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
 258  * See the COPYING.LIB file in the top-level directory.
 259  *
 260  */
 261 '''
 262 h_comment = '''
 263 /*
 264  * schema-defined QAPI types
 265  *
 266  * Copyright IBM, Corp. 2011
 267  *
 268  * Authors:
 269  *  Anthony Liguori   <aliguori@us.ibm.com>
 270  *
 271  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
 272  * See the COPYING.LIB file in the top-level directory.
 273  *
 274  */
 275 '''
 276
 277 (fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
 278                             'qapi-types.c', 'qapi-types.h',
 279                             c_comment, h_comment)
 280
 281 fdef.write(mcgen('''
 282 #include "qapi/dealloc-visitor.h"
 283 #include "%(prefix)sqapi-types.h"
 284 #include "%(prefix)sqapi-visit.h"
 285 ''',
 286                  prefix=prefix))
 287
 288 # To avoid circular headers, use only typedefs.h here, not qobject.h
 289 fdecl.write(mcgen('''
 290 #include <stdbool.h>
 291 #include <stdint.h>
 292 #include "qemu/typedefs.h"
 293 '''))
 294
 295 schema = QAPISchema(input_file)
 296 gen = QAPISchemaGenTypeVisitor()
 297 schema.visit(gen)
 298 fdef.write(gen.defn)
 299 fdecl.write(gen.decl)
 300
 301 close_output(fdef, fdecl)