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 bt_definition *_variant_definition_new(struct bt_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 bt_definition *definition);
  41
  42 int bt_variant_rw(struct bt_stream_pos *ppos, struct bt_definition *definition)
  43 {
  44         struct definition_variant *variant_definition =
  45                 container_of(definition, struct definition_variant, p);
  46         struct bt_definition *field;
  47
  48         field = bt_variant_get_current_field(variant_definition);
  49         if (!field) {
  50                 return -EINVAL;
  51         }
  52         return generic_rw(ppos, field);
  53 }
  54
  55 static
  56 void _untagged_variant_declaration_free(struct bt_declaration *declaration)
  57 {
  58         struct declaration_untagged_variant *untagged_variant_declaration =
  59                 container_of(declaration, struct declaration_untagged_variant, p);
  60         unsigned long i;
  61
  62         bt_free_declaration_scope(untagged_variant_declaration->scope);
  63         g_hash_table_destroy(untagged_variant_declaration->fields_by_tag);
  64
  65         for (i = 0; i < untagged_variant_declaration->fields->len; i++) {
  66                 struct declaration_field *declaration_field =
  67                         &g_array_index(untagged_variant_declaration->fields,
  68                                        struct declaration_field, i);
  69                 bt_declaration_unref(declaration_field->declaration);
  70         }
  71         g_array_free(untagged_variant_declaration->fields, true);
  72         g_free(untagged_variant_declaration);
  73 }
  74
  75 struct declaration_untagged_variant *bt_untagged_bt_variant_declaration_new(
  76                                       struct declaration_scope *parent_scope)
  77 {
  78         struct declaration_untagged_variant *untagged_variant_declaration;
  79         struct bt_declaration *declaration;
  80
  81         untagged_variant_declaration = g_new(struct declaration_untagged_variant, 1);
  82         declaration = &untagged_variant_declaration->p;
  83         untagged_variant_declaration->fields_by_tag = g_hash_table_new(g_direct_hash,
  84                                                        g_direct_equal);
  85         untagged_variant_declaration->fields = g_array_sized_new(FALSE, TRUE,
  86                                                  sizeof(struct declaration_field),
  87                                                  DEFAULT_NR_STRUCT_FIELDS);
  88         untagged_variant_declaration->scope = bt_new_declaration_scope(parent_scope);
  89         declaration->id = CTF_TYPE_UNTAGGED_VARIANT;
  90         declaration->alignment = 1;
  91         declaration->declaration_free = _untagged_variant_declaration_free;
  92         declaration->definition_new = NULL;
  93         declaration->definition_free = NULL;
  94         declaration->ref = 1;
  95         return untagged_variant_declaration;
  96 }
  97
  98 static
  99 void _variant_declaration_free(struct bt_declaration *declaration)
 100 {
 101         struct declaration_variant *variant_declaration =
 102                 container_of(declaration, struct declaration_variant, p);
 103
 104         bt_declaration_unref(&variant_declaration->untagged_variant->p);
 105         g_array_free(variant_declaration->tag_name, TRUE);
 106         g_free(variant_declaration);
 107 }
 108
 109 struct declaration_variant *
 110         bt_variant_declaration_new(struct declaration_untagged_variant *untagged_variant, const char *tag)
 111 {
 112         struct declaration_variant *variant_declaration;
 113         struct bt_declaration *declaration;
 114
 115         variant_declaration = g_new(struct declaration_variant, 1);
 116         declaration = &variant_declaration->p;
 117         variant_declaration->untagged_variant = untagged_variant;
 118         bt_declaration_ref(&untagged_variant->p);
 119         variant_declaration->tag_name = g_array_new(FALSE, TRUE, sizeof(GQuark));
 120         bt_append_scope_path(tag, variant_declaration->tag_name);
 121         declaration->id = CTF_TYPE_VARIANT;
 122         declaration->alignment = 1;
 123         declaration->declaration_free = _variant_declaration_free;
 124         declaration->definition_new = _variant_definition_new;
 125         declaration->definition_free = _variant_definition_free;
 126         declaration->ref = 1;
 127         return variant_declaration;
 128 }
 129
 130 static
 131 struct bt_definition *
 132         _variant_definition_new(struct bt_declaration *declaration,
 133                                 struct definition_scope *parent_scope,
 134                                 GQuark field_name, int index,
 135                                 const char *root_name)
 136 {
 137         struct declaration_variant *variant_declaration =
 138                 container_of(declaration, struct declaration_variant, p);
 139         struct definition_variant *variant;
 140         unsigned long i;
 141         int ret;
 142
 143         variant = g_new(struct definition_variant, 1);
 144         bt_declaration_ref(&variant_declaration->p);
 145         variant->p.declaration = declaration;
 146         variant->declaration = variant_declaration;
 147         variant->p.ref = 1;
 148         /*
 149          * Use INT_MAX order to ensure that all fields of the parent
 150          * scope are seen as being prior to this scope.
 151          */
 152         variant->p.index = root_name ? INT_MAX : index;
 153         variant->p.name = field_name;
 154         variant->p.path = bt_new_definition_path(parent_scope, field_name, root_name);
 155         variant->p.scope = bt_new_definition_scope(parent_scope, field_name, root_name);
 156
 157         ret = bt_register_field_definition(field_name, &variant->p,
 158                                         parent_scope);
 159         assert(!ret);
 160
 161         variant->enum_tag = bt_lookup_path_definition(variant->p.scope->scope_path,
 162                                                    variant_declaration->tag_name,
 163                                                    parent_scope);
 164
 165         if (!variant->enum_tag)
 166                 goto error;
 167         bt_definition_ref(variant->enum_tag);
 168         variant->fields = g_ptr_array_sized_new(variant_declaration->untagged_variant->fields->len);
 169         g_ptr_array_set_size(variant->fields, variant_declaration->untagged_variant->fields->len);
 170         for (i = 0; i < variant_declaration->untagged_variant->fields->len; i++) {
 171                 struct declaration_field *declaration_field =
 172                         &g_array_index(variant_declaration->untagged_variant->fields,
 173                                        struct declaration_field, i);
 174                 struct bt_definition **field =
 175                         (struct bt_definition **) &g_ptr_array_index(variant->fields, i);
 176
 177                 /*
 178                  * All child definition are at index 0, because they are
 179                  * various choices of the same field.
 180                  */
 181                 *field = declaration_field->declaration->definition_new(declaration_field->declaration,
 182                                                   variant->p.scope,
 183                                                   declaration_field->name, 0, NULL);
 184                 if (!*field)
 185                         goto error;
 186         }
 187         variant->current_field = NULL;
 188         return &variant->p;
 189 error:
 190         bt_free_definition_scope(variant->p.scope);
 191         bt_declaration_unref(&variant_declaration->p);
 192         g_free(variant);
 193         return NULL;
 194 }
 195
 196 static
 197 void _variant_definition_free(struct bt_definition *definition)
 198 {
 199         struct definition_variant *variant =
 200                 container_of(definition, struct definition_variant, p);
 201         unsigned long i;
 202
 203         assert(variant->fields->len == variant->declaration->untagged_variant->fields->len);
 204         for (i = 0; i < variant->fields->len; i++) {
 205                 struct bt_definition *field = g_ptr_array_index(variant->fields, i);
 206                 bt_definition_unref(field);
 207         }
 208         bt_definition_unref(variant->enum_tag);
 209         bt_free_definition_scope(variant->p.scope);
 210         bt_declaration_unref(variant->p.declaration);
 211         g_ptr_array_free(variant->fields, TRUE);
 212         g_free(variant);
 213 }
 214
 215 void bt_untagged_variant_declaration_add_field(struct declaration_untagged_variant *untagged_variant_declaration,
 216                             const char *field_name,
 217                             struct bt_declaration *field_declaration)
 218 {
 219         struct declaration_field *field;
 220         unsigned long index;
 221
 222         g_array_set_size(untagged_variant_declaration->fields, untagged_variant_declaration->fields->len + 1);
 223         index = untagged_variant_declaration->fields->len - 1;  /* last field (new) */
 224         field = &g_array_index(untagged_variant_declaration->fields, struct declaration_field, index);
 225         field->name = g_quark_from_string(field_name);
 226         bt_declaration_ref(field_declaration);
 227         field->declaration = field_declaration;
 228         /* Keep index in hash rather than pointer, because array can relocate */
 229         g_hash_table_insert(untagged_variant_declaration->fields_by_tag,
 230                             (gpointer) (unsigned long) field->name,
 231                             (gpointer) index);
 232         /*
 233          * Alignment of variant is based on the alignment of its currently
 234          * selected choice, so we leave variant alignment as-is (statically
 235          * speaking).
 236          */
 237 }
 238
 239 struct declaration_field *
 240 bt_untagged_variant_declaration_get_field_from_tag(struct declaration_untagged_variant *untagged_variant_declaration, GQuark tag)
 241 {
 242         gpointer index;
 243         gboolean found;
 244
 245         found = g_hash_table_lookup_extended(
 246                                 untagged_variant_declaration->fields_by_tag,
 247                                 (gconstpointer) (unsigned long) tag, NULL, &index);
 248
 249         if (!found) {
 250                 return NULL;
 251         }
 252
 253         return &g_array_index(untagged_variant_declaration->fields, struct declaration_field, (unsigned long)index);
 254 }
 255
 256 /*
 257  * field returned only valid as long as the field structure is not appended to.
 258  */
 259 struct bt_definition *bt_variant_get_current_field(struct definition_variant *variant)
 260 {
 261         struct definition_enum *_enum =
 262                 container_of(variant->enum_tag, struct definition_enum, p);
 263         struct declaration_variant *variant_declaration = variant->declaration;
 264         unsigned long index;
 265         GArray *tag_array;
 266         GQuark tag;
 267         gpointer orig_key, value;
 268
 269         tag_array = _enum->value;
 270         if (!tag_array) {
 271                 /* Enumeration has unknown tag. */
 272                 fprintf(stderr, "[error] Enumeration used for variant has unknown tag.\n");
 273                 return NULL;
 274         }
 275         /*
 276          * The 1 to 1 mapping from enumeration to value should have been already
 277          * checked. (see TODO above)
 278          */
 279         assert(tag_array->len == 1);
 280         tag = g_array_index(tag_array, GQuark, 0);
 281         if (!g_hash_table_lookup_extended(variant_declaration->untagged_variant->fields_by_tag,
 282                         (gconstpointer) (unsigned long) tag,
 283                         &orig_key,
 284                         &value)) {
 285                 /* Cannot find matching field. */
 286                 fprintf(stderr, "[error] Cannot find matching field for enum field \"%s\" in variant.\n",
 287                         g_quark_to_string(tag));
 288                 return NULL;
 289         }
 290         index = (unsigned long) value;
 291         variant->current_field = g_ptr_array_index(variant->fields, index);
 292         return variant->current_field;
 293 }