scripts/qapi/visit.py

   1 """
   2 QAPI visitor generator
   3
   4 Copyright IBM, Corp. 2011
   5 Copyright (C) 2014-2018 Red Hat, Inc.
   6
   7 Authors:
   8  Anthony Liguori <aliguori@us.ibm.com>
   9  Michael Roth    <mdroth@linux.vnet.ibm.com>
  10  Markus Armbruster <armbru@redhat.com>
  11
  12 This work is licensed under the terms of the GNU GPL, version 2.
  13 See the COPYING file in the top-level directory.
  14 """
  15
  16 from typing import List, Optional
  17
  18 from .common import (
  19     c_enum_const,
  20     c_name,
  21     indent,
  22     mcgen,
  23 )
  24 from .gen import (
  25     QAPISchemaModularCVisitor,
  26     gen_special_features,
  27     ifcontext,
  28 )
  29 from .schema import (
  30     QAPISchema,
  31     QAPISchemaAlternatives,
  32     QAPISchemaBranches,
  33     QAPISchemaEnumMember,
  34     QAPISchemaEnumType,
  35     QAPISchemaFeature,
  36     QAPISchemaIfCond,
  37     QAPISchemaObjectType,
  38     QAPISchemaObjectTypeMember,
  39     QAPISchemaType,
  40 )
  41 from .source import QAPISourceInfo
  42
  43
  44 def gen_visit_decl(name: str, scalar: bool = False) -> str:
  45     c_type = c_name(name) + ' *'
  46     if not scalar:
  47         c_type += '*'
  48     return mcgen('''
  49
  50 bool visit_type_%(c_name)s(Visitor *v, const char *name,
  51                  %(c_type)sobj, Error **errp);
  52 ''',
  53                  c_name=c_name(name), c_type=c_type)
  54
  55
  56 def gen_visit_members_decl(name: str) -> str:
  57     return mcgen('''
  58
  59 bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp);
  60 ''',
  61                  c_name=c_name(name))
  62
  63
  64 def gen_visit_object_members(name: str,
  65                              base: Optional[QAPISchemaObjectType],
  66                              members: List[QAPISchemaObjectTypeMember],
  67                              branches: Optional[QAPISchemaBranches]) -> str:
  68     ret = mcgen('''
  69
  70 bool visit_type_%(c_name)s_members(Visitor *v, %(c_name)s *obj, Error **errp)
  71 {
  72 ''',
  73                 c_name=c_name(name))
  74
  75     sep = ''
  76     for memb in members:
  77         if memb.optional and not memb.need_has():
  78             ret += memb.ifcond.gen_if()
  79             ret += mcgen('''
  80     bool has_%(c_name)s = !!obj->%(c_name)s;
  81 ''',
  82                          c_name=c_name(memb.name))
  83             sep = '\n'
  84             ret += memb.ifcond.gen_endif()
  85     ret += sep
  86
  87     if base:
  88         ret += mcgen('''
  89     if (!visit_type_%(c_type)s_members(v, (%(c_type)s *)obj, errp)) {
  90         return false;
  91     }
  92 ''',
  93                      c_type=base.c_name())
  94
  95     for memb in members:
  96         ret += memb.ifcond.gen_if()
  97         if memb.optional:
  98             has = 'has_' + c_name(memb.name)
  99             if memb.need_has():
 100                 has = 'obj->' + has
 101             ret += mcgen('''
 102     if (visit_optional(v, "%(name)s", &%(has)s)) {
 103 ''',
 104                          name=memb.name, has=has)
 105             indent.increase()
 106         special_features = gen_special_features(memb.features)
 107         if special_features != '0':
 108             ret += mcgen('''
 109     if (visit_policy_reject(v, "%(name)s", %(special_features)s, errp)) {
 110         return false;
 111     }
 112     if (!visit_policy_skip(v, "%(name)s", %(special_features)s)) {
 113 ''',
 114                          name=memb.name, special_features=special_features)
 115             indent.increase()
 116         ret += mcgen('''
 117     if (!visit_type_%(c_type)s(v, "%(name)s", &obj->%(c_name)s, errp)) {
 118         return false;
 119     }
 120 ''',
 121                      c_type=memb.type.c_name(), name=memb.name,
 122                      c_name=c_name(memb.name))
 123         if special_features != '0':
 124             indent.decrease()
 125             ret += mcgen('''
 126     }
 127 ''')
 128         if memb.optional:
 129             indent.decrease()
 130             ret += mcgen('''
 131     }
 132 ''')
 133         ret += memb.ifcond.gen_endif()
 134
 135     if branches:
 136         tag_member = branches.tag_member
 137         assert isinstance(tag_member.type, QAPISchemaEnumType)
 138
 139         ret += mcgen('''
 140     switch (obj->%(c_name)s) {
 141 ''',
 142                      c_name=c_name(tag_member.name))
 143
 144         for var in branches.variants:
 145             case_str = c_enum_const(tag_member.type.name, var.name,
 146                                     tag_member.type.prefix)
 147             ret += var.ifcond.gen_if()
 148             if var.type.name == 'q_empty':
 149                 # valid variant and nothing to do
 150                 ret += mcgen('''
 151     case %(case)s:
 152         break;
 153 ''',
 154                              case=case_str)
 155             else:
 156                 ret += mcgen('''
 157     case %(case)s:
 158         return visit_type_%(c_type)s_members(v, &obj->u.%(c_name)s, errp);
 159 ''',
 160                              case=case_str,
 161                              c_type=var.type.c_name(), c_name=c_name(var.name))
 162
 163             ret += var.ifcond.gen_endif()
 164         ret += mcgen('''
 165     default:
 166         abort();
 167     }
 168 ''')
 169
 170     ret += mcgen('''
 171     return true;
 172 }
 173 ''')
 174     return ret
 175
 176
 177 def gen_visit_list(name: str, element_type: QAPISchemaType) -> str:
 178     return mcgen('''
 179
 180 bool visit_type_%(c_name)s(Visitor *v, const char *name,
 181                  %(c_name)s **obj, Error **errp)
 182 {
 183     bool ok = false;
 184     %(c_name)s *tail;
 185     size_t size = sizeof(**obj);
 186
 187     if (!visit_start_list(v, name, (GenericList **)obj, size, errp)) {
 188         return false;
 189     }
 190
 191     for (tail = *obj; tail;
 192          tail = (%(c_name)s *)visit_next_list(v, (GenericList *)tail, size)) {
 193         if (!visit_type_%(c_elt_type)s(v, NULL, &tail->value, errp)) {
 194             goto out_obj;
 195         }
 196     }
 197
 198     ok = visit_check_list(v, errp);
 199 out_obj:
 200     visit_end_list(v, (void **)obj);
 201     if (!ok && visit_is_input(v)) {
 202         qapi_free_%(c_name)s(*obj);
 203         *obj = NULL;
 204     }
 205     return ok;
 206 }
 207 ''',
 208                  c_name=c_name(name), c_elt_type=element_type.c_name())
 209
 210
 211 def gen_visit_enum(name: str) -> str:
 212     return mcgen('''
 213
 214 bool visit_type_%(c_name)s(Visitor *v, const char *name,
 215                  %(c_name)s *obj, Error **errp)
 216 {
 217     int value = *obj;
 218     bool ok = visit_type_enum(v, name, &value, &%(c_name)s_lookup, errp);
 219     *obj = value;
 220     return ok;
 221 }
 222 ''',
 223                  c_name=c_name(name))
 224
 225
 226 def gen_visit_alternate(name: str,
 227                         alternatives: QAPISchemaAlternatives) -> str:
 228     ret = mcgen('''
 229
 230 bool visit_type_%(c_name)s(Visitor *v, const char *name,
 231                  %(c_name)s **obj, Error **errp)
 232 {
 233     bool ok = false;
 234
 235     if (!visit_start_alternate(v, name, (GenericAlternate **)obj,
 236                                sizeof(**obj), errp)) {
 237         return false;
 238     }
 239     if (!*obj) {
 240         /* incomplete */
 241         assert(visit_is_dealloc(v));
 242         ok = true;
 243         goto out_obj;
 244     }
 245     switch ((*obj)->type) {
 246 ''',
 247                 c_name=c_name(name))
 248
 249     for var in alternatives.variants:
 250         ret += var.ifcond.gen_if()
 251         ret += mcgen('''
 252     case %(case)s:
 253 ''',
 254                      case=var.type.alternate_qtype())
 255         if isinstance(var.type, QAPISchemaObjectType):
 256             ret += mcgen('''
 257         if (!visit_start_struct(v, name, NULL, 0, errp)) {
 258             break;
 259         }
 260         if (visit_type_%(c_type)s_members(v, &(*obj)->u.%(c_name)s, errp)) {
 261             ok = visit_check_struct(v, errp);
 262         }
 263         visit_end_struct(v, NULL);
 264 ''',
 265                          c_type=var.type.c_name(),
 266                          c_name=c_name(var.name))
 267         else:
 268             ret += mcgen('''
 269         ok = visit_type_%(c_type)s(v, name, &(*obj)->u.%(c_name)s, errp);
 270 ''',
 271                          c_type=var.type.c_name(),
 272                          c_name=c_name(var.name))
 273         ret += mcgen('''
 274         break;
 275 ''')
 276         ret += var.ifcond.gen_endif()
 277
 278     ret += mcgen('''
 279     case QTYPE_NONE:
 280         abort();
 281     default:
 282         assert(visit_is_input(v));
 283         error_setg(errp, "Invalid parameter type for '%%s', expected: %(name)s",
 284                          name ? name : "null");
 285         /* Avoid passing invalid *obj to qapi_free_%(c_name)s() */
 286         g_free(*obj);
 287         *obj = NULL;
 288     }
 289 out_obj:
 290     visit_end_alternate(v, (void **)obj);
 291     if (!ok && visit_is_input(v)) {
 292         qapi_free_%(c_name)s(*obj);
 293         *obj = NULL;
 294     }
 295     return ok;
 296 }
 297 ''',
 298                  name=name, c_name=c_name(name))
 299
 300     return ret
 301
 302
 303 def gen_visit_object(name: str) -> str:
 304     return mcgen('''
 305
 306 bool visit_type_%(c_name)s(Visitor *v, const char *name,
 307                  %(c_name)s **obj, Error **errp)
 308 {
 309     bool ok = false;
 310
 311     if (!visit_start_struct(v, name, (void **)obj, sizeof(%(c_name)s), errp)) {
 312         return false;
 313     }
 314     if (!*obj) {
 315         /* incomplete */
 316         assert(visit_is_dealloc(v));
 317         ok = true;
 318         goto out_obj;
 319     }
 320     if (!visit_type_%(c_name)s_members(v, *obj, errp)) {
 321         goto out_obj;
 322     }
 323     ok = visit_check_struct(v, errp);
 324 out_obj:
 325     visit_end_struct(v, (void **)obj);
 326     if (!ok && visit_is_input(v)) {
 327         qapi_free_%(c_name)s(*obj);
 328         *obj = NULL;
 329     }
 330     return ok;
 331 }
 332 ''',
 333                  c_name=c_name(name))
 334
 335
 336 class QAPISchemaGenVisitVisitor(QAPISchemaModularCVisitor):
 337
 338     def __init__(self, prefix: str):
 339         super().__init__(
 340             prefix, 'qapi-visit', ' * Schema-defined QAPI visitors',
 341             ' * Built-in QAPI visitors', __doc__)
 342
 343     def _begin_builtin_module(self) -> None:
 344         self._genc.preamble_add(mcgen('''
 345 #include "qemu/osdep.h"
 346 #include "qapi/error.h"
 347 #include "qapi/qapi-builtin-visit.h"
 348 '''))
 349         self._genh.preamble_add(mcgen('''
 350 #include "qapi/visitor.h"
 351 #include "qapi/qapi-builtin-types.h"
 352
 353 '''))
 354
 355     def _begin_user_module(self, name: str) -> None:
 356         types = self._module_basename('qapi-types', name)
 357         visit = self._module_basename('qapi-visit', name)
 358         self._genc.preamble_add(mcgen('''
 359 #include "qemu/osdep.h"
 360 #include "qapi/error.h"
 361 #include "%(visit)s.h"
 362 ''',
 363                                       visit=visit))
 364         self._genh.preamble_add(mcgen('''
 365 #include "qapi/qapi-builtin-visit.h"
 366 #include "%(types)s.h"
 367
 368 ''',
 369                                       types=types))
 370
 371     def visit_enum_type(self,
 372                         name: str,
 373                         info: Optional[QAPISourceInfo],
 374                         ifcond: QAPISchemaIfCond,
 375                         features: List[QAPISchemaFeature],
 376                         members: List[QAPISchemaEnumMember],
 377                         prefix: Optional[str]) -> None:
 378         with ifcontext(ifcond, self._genh, self._genc):
 379             self._genh.add(gen_visit_decl(name, scalar=True))
 380             self._genc.add(gen_visit_enum(name))
 381
 382     def visit_array_type(self,
 383                          name: str,
 384                          info: Optional[QAPISourceInfo],
 385                          ifcond: QAPISchemaIfCond,
 386                          element_type: QAPISchemaType) -> None:
 387         with ifcontext(ifcond, self._genh, self._genc):
 388             self._genh.add(gen_visit_decl(name))
 389             self._genc.add(gen_visit_list(name, element_type))
 390
 391     def visit_object_type(self,
 392                           name: str,
 393                           info: Optional[QAPISourceInfo],
 394                           ifcond: QAPISchemaIfCond,
 395                           features: List[QAPISchemaFeature],
 396                           base: Optional[QAPISchemaObjectType],
 397                           members: List[QAPISchemaObjectTypeMember],
 398                           branches: Optional[QAPISchemaBranches]) -> None:
 399         # Nothing to do for the special empty builtin
 400         if name == 'q_empty':
 401             return
 402         with ifcontext(ifcond, self._genh, self._genc):
 403             self._genh.add(gen_visit_members_decl(name))
 404             self._genc.add(gen_visit_object_members(name, base,
 405                                                     members, branches))
 406             # TODO Worth changing the visitor signature, so we could
 407             # directly use rather than repeat type.is_implicit()?
 408             if not name.startswith('q_'):
 409                 # only explicit types need an allocating visit
 410                 self._genh.add(gen_visit_decl(name))
 411                 self._genc.add(gen_visit_object(name))
 412
 413     def visit_alternate_type(self,
 414                              name: str,
 415                              info: Optional[QAPISourceInfo],
 416                              ifcond: QAPISchemaIfCond,
 417                              features: List[QAPISchemaFeature],
 418                              alternatives: QAPISchemaAlternatives) -> None:
 419         with ifcontext(ifcond, self._genh, self._genc):
 420             self._genh.add(gen_visit_decl(name))
 421             self._genc.add(gen_visit_alternate(name, alternatives))
 422
 423
 424 def gen_visit(schema: QAPISchema,
 425               output_dir: str,
 426               prefix: str,
 427               opt_builtins: bool) -> None:
 428     vis = QAPISchemaGenVisitVisitor(prefix)
 429     schema.visit(vis)
 430     vis.write(output_dir, opt_builtins)