scripts/qapi/types.py

   1 """
   2 QAPI types generator
   3
   4 Copyright IBM, Corp. 2011
   5 Copyright (c) 2013-2018 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 qapi.common import *
  17
  18
  19 # variants must be emitted before their container; track what has already
  20 # been output
  21 objects_seen = set()
  22
  23
  24 def gen_fwd_object_or_array(name):
  25     return mcgen('''
  26
  27 typedef struct %(c_name)s %(c_name)s;
  28 ''',
  29                  c_name=c_name(name))
  30
  31
  32 def gen_array(name, element_type):
  33     return mcgen('''
  34
  35 struct %(c_name)s {
  36     %(c_name)s *next;
  37     %(c_type)s value;
  38 };
  39 ''',
  40                  c_name=c_name(name), c_type=element_type.c_type())
  41
  42
  43 def gen_struct_members(members):
  44     ret = ''
  45     for memb in members:
  46         if memb.optional:
  47             ret += mcgen('''
  48     bool has_%(c_name)s;
  49 ''',
  50                          c_name=c_name(memb.name))
  51         ret += mcgen('''
  52     %(c_type)s %(c_name)s;
  53 ''',
  54                      c_type=memb.type.c_type(), c_name=c_name(memb.name))
  55     return ret
  56
  57
  58 def gen_object(name, base, members, variants):
  59     if name in objects_seen:
  60         return ''
  61     objects_seen.add(name)
  62
  63     ret = ''
  64     if variants:
  65         for v in variants.variants:
  66             if isinstance(v.type, QAPISchemaObjectType):
  67                 ret += gen_object(v.type.name, v.type.base,
  68                                   v.type.local_members, v.type.variants)
  69
  70     ret += mcgen('''
  71
  72 struct %(c_name)s {
  73 ''',
  74                  c_name=c_name(name))
  75
  76     if base:
  77         if not base.is_implicit():
  78             ret += mcgen('''
  79     /* Members inherited from %(c_name)s: */
  80 ''',
  81                          c_name=base.c_name())
  82         ret += gen_struct_members(base.members)
  83         if not base.is_implicit():
  84             ret += mcgen('''
  85     /* Own members: */
  86 ''')
  87     ret += gen_struct_members(members)
  88
  89     if variants:
  90         ret += gen_variants(variants)
  91
  92     # Make sure that all structs have at least one member; this avoids
  93     # potential issues with attempting to malloc space for zero-length
  94     # structs in C, and also incompatibility with C++ (where an empty
  95     # struct is size 1).
  96     if (not base or base.is_empty()) and not members and not variants:
  97         ret += mcgen('''
  98     char qapi_dummy_for_empty_struct;
  99 ''')
 100
 101     ret += mcgen('''
 102 };
 103 ''')
 104
 105     return ret
 106
 107
 108 def gen_upcast(name, base):
 109     # C makes const-correctness ugly.  We have to cast away const to let
 110     # this function work for both const and non-const obj.
 111     return mcgen('''
 112
 113 static inline %(base)s *qapi_%(c_name)s_base(const %(c_name)s *obj)
 114 {
 115     return (%(base)s *)obj;
 116 }
 117 ''',
 118                  c_name=c_name(name), base=base.c_name())
 119
 120
 121 def gen_variants(variants):
 122     ret = mcgen('''
 123     union { /* union tag is @%(c_name)s */
 124 ''',
 125                 c_name=c_name(variants.tag_member.name))
 126
 127     for var in variants.variants:
 128         ret += mcgen('''
 129         %(c_type)s %(c_name)s;
 130 ''',
 131                      c_type=var.type.c_unboxed_type(),
 132                      c_name=c_name(var.name))
 133
 134     ret += mcgen('''
 135     } u;
 136 ''')
 137
 138     return ret
 139
 140
 141 def gen_type_cleanup_decl(name):
 142     ret = mcgen('''
 143
 144 void qapi_free_%(c_name)s(%(c_name)s *obj);
 145 ''',
 146                 c_name=c_name(name))
 147     return ret
 148
 149
 150 def gen_type_cleanup(name):
 151     ret = mcgen('''
 152
 153 void qapi_free_%(c_name)s(%(c_name)s *obj)
 154 {
 155     Visitor *v;
 156
 157     if (!obj) {
 158         return;
 159     }
 160
 161     v = qapi_dealloc_visitor_new();
 162     visit_type_%(c_name)s(v, NULL, &obj, NULL);
 163     visit_free(v);
 164 }
 165 ''',
 166                 c_name=c_name(name))
 167     return ret
 168
 169
 170 class QAPISchemaGenTypeVisitor(QAPISchemaVisitor):
 171     def __init__(self, opt_builtins):
 172         self._opt_builtins = opt_builtins
 173         self.decl = None
 174         self.defn = None
 175         self._fwdecl = None
 176         self._btin = None
 177
 178     def visit_begin(self, schema):
 179         # gen_object() is recursive, ensure it doesn't visit the empty type
 180         objects_seen.add(schema.the_empty_object_type.name)
 181         self.decl = ''
 182         self.defn = ''
 183         self._fwdecl = ''
 184         self._btin = '\n' + guardstart('QAPI_TYPES_BUILTIN')
 185
 186     def visit_end(self):
 187         self.decl = self._fwdecl + self.decl
 188         self._fwdecl = None
 189         # To avoid header dependency hell, we always generate
 190         # declarations for built-in types in our header files and
 191         # simply guard them.  See also opt_builtins (command line
 192         # option -b).
 193         self._btin += guardend('QAPI_TYPES_BUILTIN')
 194         self.decl = self._btin + self.decl
 195         self._btin = None
 196
 197     def _gen_type_cleanup(self, name):
 198         self.decl += gen_type_cleanup_decl(name)
 199         self.defn += gen_type_cleanup(name)
 200
 201     def visit_enum_type(self, name, info, values, prefix):
 202         # Special case for our lone builtin enum type
 203         # TODO use something cleaner than existence of info
 204         if not info:
 205             self._btin += gen_enum(name, values, prefix)
 206             if self._opt_builtins:
 207                 self.defn += gen_enum_lookup(name, values, prefix)
 208         else:
 209             self._fwdecl += gen_enum(name, values, prefix)
 210             self.defn += gen_enum_lookup(name, values, prefix)
 211
 212     def visit_array_type(self, name, info, element_type):
 213         if isinstance(element_type, QAPISchemaBuiltinType):
 214             self._btin += gen_fwd_object_or_array(name)
 215             self._btin += gen_array(name, element_type)
 216             self._btin += gen_type_cleanup_decl(name)
 217             if self._opt_builtins:
 218                 self.defn += gen_type_cleanup(name)
 219         else:
 220             self._fwdecl += gen_fwd_object_or_array(name)
 221             self.decl += gen_array(name, element_type)
 222             self._gen_type_cleanup(name)
 223
 224     def visit_object_type(self, name, info, base, members, variants):
 225         # Nothing to do for the special empty builtin
 226         if name == 'q_empty':
 227             return
 228         self._fwdecl += gen_fwd_object_or_array(name)
 229         self.decl += gen_object(name, base, members, variants)
 230         if base and not base.is_implicit():
 231             self.decl += gen_upcast(name, base)
 232         # TODO Worth changing the visitor signature, so we could
 233         # directly use rather than repeat type.is_implicit()?
 234         if not name.startswith('q_'):
 235             # implicit types won't be directly allocated/freed
 236             self._gen_type_cleanup(name)
 237
 238     def visit_alternate_type(self, name, info, variants):
 239         self._fwdecl += gen_fwd_object_or_array(name)
 240         self.decl += gen_object(name, None, [variants.tag_member], variants)
 241         self._gen_type_cleanup(name)
 242
 243
 244 def gen_types(schema, output_dir, prefix, opt_builtins):
 245     blurb = ' * Schema-defined QAPI types'
 246     genc = QAPIGenC(blurb, __doc__)
 247     genh = QAPIGenH(blurb, __doc__)
 248
 249     genc.add(mcgen('''
 250 #include "qemu/osdep.h"
 251 #include "qapi/dealloc-visitor.h"
 252 #include "%(prefix)sqapi-types.h"
 253 #include "%(prefix)sqapi-visit.h"
 254 ''',
 255                    prefix=prefix))
 256
 257     genh.add(mcgen('''
 258 #include "qapi/util.h"
 259 '''))
 260
 261     vis = QAPISchemaGenTypeVisitor(opt_builtins)
 262     schema.visit(vis)
 263     genc.add(vis.defn)
 264     genh.add(vis.decl)
 265     genc.write(output_dir, prefix + 'qapi-types.c')
 266     genh.write(output_dir, prefix + 'qapi-types.h')