types/variant.c

   1 /*
   2  * variant.c
   3  *
   4  * BabelTrace - Variant Type Converter
   5  *
   6  * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  */
  18
  19 #include <babeltrace/compiler.h>
  20 #include <babeltrace/format.h>
  21 #include <errno.h>
  22
  23 static
  24 struct definition *_variant_definition_new(struct declaration *declaration,
  25                                 struct definition_scope *parent_scope,
  26                                 GQuark field_name, int index);
  27 static
  28 void _variant_definition_free(struct definition *definition);
  29
  30 void variant_copy(struct stream_pos *dest, const struct format *fdest,
  31                   struct stream_pos *src, const struct format *fsrc,
  32                   struct definition *definition)
  33 {
  34         struct definition_variant *variant =
  35                 container_of(definition, struct definition_variant, p);
  36         struct declaration_variant *variant_declaration = variant->declaration;
  37         struct field *field;
  38         struct declaration *field_declaration;
  39
  40         fsrc->variant_begin(src, variant_declaration);
  41         fdest->variant_begin(dest, variant_declaration);
  42
  43         field = variant_get_current_field(variant);
  44         field_declaration = field->definition->declaration;
  45         field_declaration->copy(dest, fdest, src, fsrc, field->definition);
  46
  47         fsrc->variant_end(src, variant_declaration);
  48         fdest->variant_end(dest, variant_declaration);
  49 }
  50
  51 static
  52 void _untagged_variant_declaration_free(struct declaration *declaration)
  53 {
  54         struct declaration_untagged_variant *untagged_variant_declaration =
  55                 container_of(declaration, struct declaration_untagged_variant, p);
  56         unsigned long i;
  57
  58         free_declaration_scope(untagged_variant_declaration->scope);
  59         g_hash_table_destroy(untagged_variant_declaration->fields_by_tag);
  60
  61         for (i = 0; i < untagged_variant_declaration->fields->len; i++) {
  62                 struct declaration_field *declaration_field =
  63                         &g_array_index(untagged_variant_declaration->fields,
  64                                        struct declaration_field, i);
  65                 declaration_unref(declaration_field->declaration);
  66         }
  67         g_array_free(untagged_variant_declaration->fields, true);
  68         g_free(untagged_variant_declaration);
  69 }
  70
  71 struct declaration_untagged_variant *untagged_variant_declaration_new(
  72                                       struct declaration_scope *parent_scope)
  73 {
  74         struct declaration_untagged_variant *untagged_variant_declaration;
  75         struct declaration *declaration;
  76
  77         untagged_variant_declaration = g_new(struct declaration_untagged_variant, 1);
  78         declaration = &untagged_variant_declaration->p;
  79         untagged_variant_declaration->fields_by_tag = g_hash_table_new(g_direct_hash,
  80                                                        g_direct_equal);
  81         untagged_variant_declaration->fields = g_array_sized_new(FALSE, TRUE,
  82                                                  sizeof(struct declaration_field),
  83                                                  DEFAULT_NR_STRUCT_FIELDS);
  84         untagged_variant_declaration->scope = new_declaration_scope(parent_scope);
  85         declaration->id = CTF_TYPE_UNTAGGED_VARIANT;
  86         declaration->alignment = 1;
  87         declaration->copy = NULL;
  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         _untagged_variant_declaration_free(&variant_declaration->untagged_variant->p);
 102         g_array_free(variant_declaration->tag_name, TRUE);
 103 }
 104
 105 struct declaration_variant *
 106         variant_declaration_new(struct declaration_untagged_variant *untagged_variant, const char *tag)
 107 {
 108         struct declaration_variant *variant_declaration;
 109         struct declaration *declaration;
 110
 111         variant_declaration = g_new(struct declaration_variant, 1);
 112         declaration = &variant_declaration->p;
 113         variant_declaration->untagged_variant = untagged_variant;
 114         variant_declaration->tag_name = g_array_new(FALSE, TRUE, sizeof(GQuark));
 115         append_scope_path(tag, variant_declaration->tag_name);
 116         declaration->id = CTF_TYPE_VARIANT;
 117         declaration->alignment = 1;
 118         declaration->copy = variant_copy;
 119         declaration->declaration_free = _variant_declaration_free;
 120         declaration->definition_new = _variant_definition_new;
 121         declaration->definition_free = _variant_definition_free;
 122         declaration->ref = 1;
 123         return variant_declaration;
 124 }
 125
 126 /*
 127  * tag_instance is assumed to be an enumeration.
 128  * Returns 0 if OK, < 0 if error.
 129  */
 130 static
 131 int check_enum_tag(struct definition_variant *variant,
 132                    struct definition *enum_tag)
 133 {
 134         struct definition_enum *_enum =
 135                 container_of(enum_tag, struct definition_enum, p);
 136         struct declaration_enum *enum_declaration = _enum->declaration;
 137         int missing_field = 0;
 138         unsigned long i;
 139
 140         /*
 141          * Strictly speaking, each enumerator must map to a field of the
 142          * variant. However, we are even stricter here by requiring that each
 143          * variant choice map to an enumerator too. We then validate that the
 144          * number of enumerators equals the number of variant choices.
 145          */
 146         if (variant->declaration->untagged_variant->fields->len != enum_get_nr_enumerators(enum_declaration))
 147                 return -EPERM;
 148
 149         for (i = 0; i < variant->declaration->untagged_variant->fields->len; i++) {
 150                 struct declaration_field *field_declaration =
 151                         &g_array_index(variant->declaration->untagged_variant->fields,
 152                                        struct declaration_field, i);
 153                 if (!enum_quark_to_range_set(enum_declaration, field_declaration->name)) {
 154                         missing_field = 1;
 155                         break;
 156                 }
 157         }
 158         if (missing_field)
 159                 return -EPERM;
 160
 161         /*
 162          * Check the enumeration: it must map each value to one and only one
 163          * enumerator tag.
 164          * TODO: we should also check that each range map to one and only one
 165          * tag. For the moment, we will simply check this dynamically in
 166          * variant_declaration_get_current_field().
 167          */
 168         return 0;
 169 }
 170
 171
 172
 173 static
 174 struct definition *
 175         _variant_definition_new(struct declaration *declaration,
 176                                 struct definition_scope *parent_scope,
 177                                 GQuark field_name, int index)
 178 {
 179         struct declaration_variant *variant_declaration =
 180                 container_of(declaration, struct declaration_variant, p);
 181         struct definition_variant *variant;
 182         unsigned long i;
 183
 184         variant = g_new(struct definition_variant, 1);
 185         declaration_ref(&variant_declaration->p);
 186         variant->p.declaration = declaration;
 187         variant->declaration = variant_declaration;
 188         variant->p.ref = 1;
 189         variant->p.index = index;
 190         variant->scope = new_definition_scope(parent_scope, field_name);
 191         variant->enum_tag = lookup_definition(variant->scope->scope_path,
 192                                               variant_declaration->tag_name,
 193                                               parent_scope);
 194
 195         if (!variant->enum_tag
 196             || check_enum_tag(variant, variant->enum_tag) < 0)
 197                 goto error;
 198         definition_ref(variant->enum_tag);
 199         variant->fields = g_array_sized_new(FALSE, TRUE,
 200                                             sizeof(struct field),
 201                                             variant_declaration->untagged_variant->fields->len);
 202         g_array_set_size(variant->fields, variant_declaration->untagged_variant->fields->len);
 203         for (i = 0; i < variant_declaration->untagged_variant->fields->len; i++) {
 204                 struct declaration_field *declaration_field =
 205                         &g_array_index(variant_declaration->untagged_variant->fields,
 206                                        struct declaration_field, i);
 207                 struct field *field = &g_array_index(variant->fields,
 208                                                      struct field, i);
 209
 210                 field->name = declaration_field->name;
 211                 /*
 212                  * All child definition are at index 0, because they are
 213                  * various choices of the same field.
 214                  */
 215                 field->definition =
 216                         declaration_field->declaration->definition_new(declaration_field->declaration,
 217                                                           variant->scope,
 218                                                           field->name, 0);
 219         }
 220         variant->current_field = NULL;
 221         return &variant->p;
 222 error:
 223         free_definition_scope(variant->scope);
 224         declaration_unref(&variant_declaration->p);
 225         g_free(variant);
 226         return NULL;
 227 }
 228
 229 static
 230 void _variant_definition_free(struct definition *definition)
 231 {
 232         struct definition_variant *variant =
 233                 container_of(definition, struct definition_variant, p);
 234         unsigned long i;
 235
 236         assert(variant->fields->len == variant->declaration->untagged_variant->fields->len);
 237         for (i = 0; i < variant->fields->len; i++) {
 238                 struct field *field = &g_array_index(variant->fields,
 239                                                      struct field, i);
 240                 definition_unref(field->definition);
 241         }
 242         definition_unref(variant->enum_tag);
 243         free_definition_scope(variant->scope);
 244         declaration_unref(variant->p.declaration);
 245         g_free(variant);
 246 }
 247
 248 void untagged_variant_declaration_add_field(struct declaration_untagged_variant *untagged_variant_declaration,
 249                             const char *field_name,
 250                             struct declaration *field_declaration)
 251 {
 252         struct declaration_field *field;
 253         unsigned long index;
 254
 255         g_array_set_size(untagged_variant_declaration->fields, untagged_variant_declaration->fields->len + 1);
 256         index = untagged_variant_declaration->fields->len - 1;  /* last field (new) */
 257         field = &g_array_index(untagged_variant_declaration->fields, struct declaration_field, index);
 258         field->name = g_quark_from_string(field_name);
 259         declaration_ref(field_declaration);
 260         field->declaration = field_declaration;
 261         /* Keep index in hash rather than pointer, because array can relocate */
 262         g_hash_table_insert(untagged_variant_declaration->fields_by_tag,
 263                             (gpointer) (unsigned long) field->name,
 264                             (gpointer) index);
 265         /*
 266          * Alignment of variant is based on the alignment of its currently
 267          * selected choice, so we leave variant alignment as-is (statically
 268          * speaking).
 269          */
 270 }
 271
 272 struct declaration_field *
 273 untagged_variant_declaration_get_field_from_tag(struct declaration_untagged_variant *untagged_variant_declaration, GQuark tag)
 274 {
 275         unsigned long index;
 276
 277         index = (unsigned long) g_hash_table_lookup(untagged_variant_declaration->fields_by_tag,
 278                                                     (gconstpointer) (unsigned long) tag);
 279         return &g_array_index(untagged_variant_declaration->fields, struct declaration_field, index);
 280 }
 281
 282 /*
 283  * field returned only valid as long as the field structure is not appended to.
 284  */
 285 struct field *variant_get_current_field(struct definition_variant *variant)
 286 {
 287         struct definition_enum *_enum =
 288                 container_of(variant->enum_tag, struct definition_enum, p);
 289         struct declaration_variant *variant_declaration = variant->declaration;
 290         unsigned long index;
 291         GArray *tag_array;
 292         GQuark tag;
 293
 294         tag_array = _enum->value;
 295         /*
 296          * The 1 to 1 mapping from enumeration to value should have been already
 297          * checked. (see TODO above)
 298          */
 299         assert(tag_array->len == 1);
 300         tag = g_array_index(tag_array, GQuark, 0);
 301         index = (unsigned long) g_hash_table_lookup(variant_declaration->untagged_variant->fields_by_tag,
 302                                                     (gconstpointer) (unsigned long) tag);
 303         variant->current_field = &g_array_index(variant->fields, struct field, index);
 304         return variant->current_field;
 305 }