types/variant.c

   1 /*
   2  * variant.c
   3  *
   4  * BabelTrace - Variant Type Converter
   5  *
   6  * Copyright 2010-2011 EfficiOS Inc. and Linux Foundation
   7  *
   8  * Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining a copy
  11  * of this software and associated documentation files (the "Software"), to deal
  12  * in the Software without restriction, including without limitation the rights
  13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  14  * copies of the Software, and to permit persons to whom the Software is
  15  * furnished to do so, subject to the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be included in
  18  * all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  23  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  26  * SOFTWARE.
  27  */
  28
  29 #include <babeltrace/compiler.h>
  30 #include <babeltrace/format.h>
  31 #include <babeltrace/types.h>
  32 #include <errno.h>
  33
  34 static
  35 struct definition *_variant_definition_new(struct declaration *declaration,
  36                                 struct definition_scope *parent_scope,
  37                                 GQuark field_name, int index,
  38                                 const char *root_name);
  39 static
  40 void _variant_definition_free(struct definition *definition);
  41
  42 int bt_variant_rw(struct stream_pos *ppos, struct definition *definition)
  43 {
  44         struct definition_variant *variant_definition =
  45                 container_of(definition, struct definition_variant, p);
  46         struct definition *field;
  47
  48         field = bt_variant_get_current_field(variant_definition);
  49         return generic_rw(ppos, field);
  50 }
  51
  52 static
  53 void _untagged_variant_declaration_free(struct declaration *declaration)
  54 {
  55         struct declaration_untagged_variant *untagged_variant_declaration =
  56                 container_of(declaration, struct declaration_untagged_variant, p);
  57         unsigned long i;
  58
  59         bt_free_declaration_scope(untagged_variant_declaration->scope);
  60         g_hash_table_destroy(untagged_variant_declaration->fields_by_tag);
  61
  62         for (i = 0; i < untagged_variant_declaration->fields->len; i++) {
  63                 struct declaration_field *declaration_field =
  64                         &g_array_index(untagged_variant_declaration->fields,
  65                                        struct declaration_field, i);
  66                 bt_declaration_unref(declaration_field->declaration);
  67         }
  68         g_array_free(untagged_variant_declaration->fields, true);
  69         g_free(untagged_variant_declaration);
  70 }
  71
  72 struct declaration_untagged_variant *bt_untagged_bt_variant_declaration_new(
  73                                       struct declaration_scope *parent_scope)
  74 {
  75         struct declaration_untagged_variant *untagged_variant_declaration;
  76         struct declaration *declaration;
  77
  78         untagged_variant_declaration = g_new(struct declaration_untagged_variant, 1);
  79         declaration = &untagged_variant_declaration->p;
  80         untagged_variant_declaration->fields_by_tag = g_hash_table_new(g_direct_hash,
  81                                                        g_direct_equal);
  82         untagged_variant_declaration->fields = g_array_sized_new(FALSE, TRUE,
  83                                                  sizeof(struct declaration_field),
  84                                                  DEFAULT_NR_STRUCT_FIELDS);
  85         untagged_variant_declaration->scope = bt_new_declaration_scope(parent_scope);
  86         declaration->id = CTF_TYPE_UNTAGGED_VARIANT;
  87         declaration->alignment = 1;
  88         declaration->declaration_free = _untagged_variant_declaration_free;
  89         declaration->definition_new = NULL;
  90         declaration->definition_free = NULL;
  91         declaration->ref = 1;
  92         return untagged_variant_declaration;
  93 }
  94
  95 static
  96 void _variant_declaration_free(struct declaration *declaration)
  97 {
  98         struct declaration_variant *variant_declaration =
  99                 container_of(declaration, struct declaration_variant, p);
 100
 101         bt_declaration_unref(&variant_declaration->untagged_variant->p);
 102         g_array_free(variant_declaration->tag_name, TRUE);
 103         g_free(variant_declaration);
 104 }
 105
 106 struct declaration_variant *
 107         bt_variant_declaration_new(struct declaration_untagged_variant *untagged_variant, const char *tag)
 108 {
 109         struct declaration_variant *variant_declaration;
 110         struct declaration *declaration;
 111
 112         variant_declaration = g_new(struct declaration_variant, 1);
 113         declaration = &variant_declaration->p;
 114         variant_declaration->untagged_variant = untagged_variant;
 115         bt_declaration_ref(&untagged_variant->p);
 116         variant_declaration->tag_name = g_array_new(FALSE, TRUE, sizeof(GQuark));
 117         bt_append_scope_path(tag, variant_declaration->tag_name);
 118         declaration->id = CTF_TYPE_VARIANT;
 119         declaration->alignment = 1;
 120         declaration->declaration_free = _variant_declaration_free;
 121         declaration->definition_new = _variant_definition_new;
 122         declaration->definition_free = _variant_definition_free;
 123         declaration->ref = 1;
 124         return variant_declaration;
 125 }
 126
 127 /*
 128  * tag_instance is assumed to be an enumeration.
 129  * Returns 0 if OK, < 0 if error.
 130  */
 131 static
 132 int check_enum_tag(struct definition_variant *variant,
 133                    struct definition *enum_tag)
 134 {
 135         struct definition_enum *_enum =
 136                 container_of(enum_tag, struct definition_enum, p);
 137         struct declaration_enum *enum_declaration = _enum->declaration;
 138         int missing_field = 0;
 139         unsigned long i;
 140
 141         /*
 142          * Strictly speaking, each enumerator must map to a field of the
 143          * variant. However, we are even stricter here by requiring that each
 144          * variant choice map to an enumerator too. We then validate that the
 145          * number of enumerators equals the number of variant choices.
 146          */
 147         if (variant->declaration->untagged_variant->fields->len != bt_enum_get_nr_enumerators(enum_declaration))
 148                 return -EPERM;
 149
 150         for (i = 0; i < variant->declaration->untagged_variant->fields->len; i++) {
 151                 struct declaration_field *field_declaration =
 152                         &g_array_index(variant->declaration->untagged_variant->fields,
 153                                        struct declaration_field, i);
 154                 if (!bt_enum_quark_to_range_set(enum_declaration, field_declaration->name)) {
 155                         missing_field = 1;
 156                         break;
 157                 }
 158         }
 159         if (missing_field)
 160                 return -EPERM;
 161
 162         /*
 163          * Check the enumeration: it must map each value to one and only one
 164          * enumerator tag.
 165          * TODO: we should also check that each range map to one and only one
 166          * tag. For the moment, we will simply check this dynamically in
 167          * variant_declaration_get_current_field().
 168          */
 169         return 0;
 170 }
 171
 172
 173
 174 static
 175 struct definition *
 176         _variant_definition_new(struct declaration *declaration,
 177                                 struct definition_scope *parent_scope,
 178                                 GQuark field_name, int index,
 179                                 const char *root_name)
 180 {
 181         struct declaration_variant *variant_declaration =
 182                 container_of(declaration, struct declaration_variant, p);
 183         struct definition_variant *variant;
 184         unsigned long i;
 185         int ret;
 186
 187         variant = g_new(struct definition_variant, 1);
 188         bt_declaration_ref(&variant_declaration->p);
 189         variant->p.declaration = declaration;
 190         variant->declaration = variant_declaration;
 191         variant->p.ref = 1;
 192         /*
 193          * Use INT_MAX order to ensure that all fields of the parent
 194          * scope are seen as being prior to this scope.
 195          */
 196         variant->p.index = root_name ? INT_MAX : index;
 197         variant->p.name = field_name;
 198         variant->p.path = new_definition_path(parent_scope, field_name, root_name);
 199         variant->p.scope = new_definition_scope(parent_scope, field_name, root_name);
 200
 201         ret = register_field_definition(field_name, &variant->p,
 202                                         parent_scope);
 203         assert(!ret);
 204
 205         variant->enum_tag = lookup_path_definition(variant->p.scope->scope_path,
 206                                                    variant_declaration->tag_name,
 207                                                    parent_scope);
 208
 209         if (!variant->enum_tag
 210             || check_enum_tag(variant, variant->enum_tag) < 0)
 211                 goto error;
 212         bt_definition_ref(variant->enum_tag);
 213         variant->fields = g_ptr_array_sized_new(variant_declaration->untagged_variant->fields->len);
 214         g_ptr_array_set_size(variant->fields, variant_declaration->untagged_variant->fields->len);
 215         for (i = 0; i < variant_declaration->untagged_variant->fields->len; i++) {
 216                 struct declaration_field *declaration_field =
 217                         &g_array_index(variant_declaration->untagged_variant->fields,
 218                                        struct declaration_field, i);
 219                 struct definition **field =
 220                         (struct definition **) &g_ptr_array_index(variant->fields, i);
 221
 222                 /*
 223                  * All child definition are at index 0, because they are
 224                  * various choices of the same field.
 225                  */
 226                 *field = declaration_field->declaration->definition_new(declaration_field->declaration,
 227                                                   variant->p.scope,
 228                                                   declaration_field->name, 0, NULL);
 229                 if (!*field)
 230                         goto error;
 231         }
 232         variant->current_field = NULL;
 233         return &variant->p;
 234 error:
 235         free_definition_scope(variant->p.scope);
 236         bt_declaration_unref(&variant_declaration->p);
 237         g_free(variant);
 238         return NULL;
 239 }
 240
 241 static
 242 void _variant_definition_free(struct definition *definition)
 243 {
 244         struct definition_variant *variant =
 245                 container_of(definition, struct definition_variant, p);
 246         unsigned long i;
 247
 248         assert(variant->fields->len == variant->declaration->untagged_variant->fields->len);
 249         for (i = 0; i < variant->fields->len; i++) {
 250                 struct definition *field = g_ptr_array_index(variant->fields, i);
 251                 bt_definition_unref(field);
 252         }
 253         bt_definition_unref(variant->enum_tag);
 254         free_definition_scope(variant->p.scope);
 255         bt_declaration_unref(variant->p.declaration);
 256         g_ptr_array_free(variant->fields, TRUE);
 257         g_free(variant);
 258 }
 259
 260 void bt_untagged_variant_declaration_add_field(struct declaration_untagged_variant *untagged_variant_declaration,
 261                             const char *field_name,
 262                             struct declaration *field_declaration)
 263 {
 264         struct declaration_field *field;
 265         unsigned long index;
 266
 267         g_array_set_size(untagged_variant_declaration->fields, untagged_variant_declaration->fields->len + 1);
 268         index = untagged_variant_declaration->fields->len - 1;  /* last field (new) */
 269         field = &g_array_index(untagged_variant_declaration->fields, struct declaration_field, index);
 270         field->name = g_quark_from_string(field_name);
 271         bt_declaration_ref(field_declaration);
 272         field->declaration = field_declaration;
 273         /* Keep index in hash rather than pointer, because array can relocate */
 274         g_hash_table_insert(untagged_variant_declaration->fields_by_tag,
 275                             (gpointer) (unsigned long) field->name,
 276                             (gpointer) index);
 277         /*
 278          * Alignment of variant is based on the alignment of its currently
 279          * selected choice, so we leave variant alignment as-is (statically
 280          * speaking).
 281          */
 282 }
 283
 284 struct declaration_field *
 285 bt_untagged_variant_declaration_get_field_from_tag(struct declaration_untagged_variant *untagged_variant_declaration, GQuark tag)
 286 {
 287         gpointer index;
 288         gboolean found;
 289
 290         found = g_hash_table_lookup_extended(
 291                                 untagged_variant_declaration->fields_by_tag,
 292                                 (gconstpointer) (unsigned long) tag, NULL, &index);
 293
 294         if (!found) {
 295                 return NULL;
 296         }
 297
 298         return &g_array_index(untagged_variant_declaration->fields, struct declaration_field, (unsigned long)index);
 299 }
 300
 301 /*
 302  * field returned only valid as long as the field structure is not appended to.
 303  */
 304 struct definition *bt_variant_get_current_field(struct definition_variant *variant)
 305 {
 306         struct definition_enum *_enum =
 307                 container_of(variant->enum_tag, struct definition_enum, p);
 308         struct declaration_variant *variant_declaration = variant->declaration;
 309         unsigned long index;
 310         GArray *tag_array;
 311         GQuark tag;
 312
 313         tag_array = _enum->value;
 314         /*
 315          * The 1 to 1 mapping from enumeration to value should have been already
 316          * checked. (see TODO above)
 317          */
 318         assert(tag_array->len == 1);
 319         tag = g_array_index(tag_array, GQuark, 0);
 320         index = (unsigned long) g_hash_table_lookup(variant_declaration->untagged_variant->fields_by_tag,
 321                                                     (gconstpointer) (unsigned long) tag);
 322         variant->current_field = g_ptr_array_index(variant->fields, index);
 323         return variant->current_field;
 324 }