| 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 declaration *_variant_declaration_new(struct type *type, |
| 25 | struct declaration_scope *parent_scope); |
| 26 | static |
| 27 | void _variant_declaration_free(struct declaration *declaration); |
| 28 | |
| 29 | void variant_copy(struct stream_pos *dest, const struct format *fdest, |
| 30 | struct stream_pos *src, const struct format *fsrc, |
| 31 | struct declaration *declaration) |
| 32 | { |
| 33 | struct declaration_variant *variant = |
| 34 | container_of(declaration, struct declaration_variant, p); |
| 35 | struct type_variant *variant_type = variant->type; |
| 36 | struct field *field; |
| 37 | struct type *field_type; |
| 38 | |
| 39 | fsrc->variant_begin(src, variant_type); |
| 40 | fdest->variant_begin(dest, variant_type); |
| 41 | |
| 42 | field = variant_get_current_field(variant); |
| 43 | field_type = field->declaration->type; |
| 44 | field_type->copy(dest, fdest, src, fsrc, field->declaration); |
| 45 | |
| 46 | fsrc->variant_end(src, variant_type); |
| 47 | fdest->variant_end(dest, variant_type); |
| 48 | } |
| 49 | |
| 50 | static |
| 51 | void _variant_type_free(struct type *type) |
| 52 | { |
| 53 | struct type_variant *variant_type = |
| 54 | container_of(type, struct type_variant, p); |
| 55 | unsigned long i; |
| 56 | |
| 57 | free_type_scope(variant_type->scope); |
| 58 | g_hash_table_destroy(variant_type->fields_by_tag); |
| 59 | |
| 60 | for (i = 0; i < variant_type->fields->len; i++) { |
| 61 | struct type_field *type_field = |
| 62 | &g_array_index(variant_type->fields, |
| 63 | struct type_field, i); |
| 64 | type_unref(type_field->type); |
| 65 | } |
| 66 | g_array_free(variant_type->fields, true); |
| 67 | g_free(variant_type); |
| 68 | } |
| 69 | |
| 70 | struct type_variant *variant_type_new(const char *name, |
| 71 | struct type_scope *parent_scope) |
| 72 | { |
| 73 | struct type_variant *variant_type; |
| 74 | struct type *type; |
| 75 | |
| 76 | variant_type = g_new(struct type_variant, 1); |
| 77 | type = &variant_type->p; |
| 78 | variant_type->fields_by_tag = g_hash_table_new(g_direct_hash, |
| 79 | g_direct_equal); |
| 80 | variant_type->fields = g_array_sized_new(FALSE, TRUE, |
| 81 | sizeof(struct type_field), |
| 82 | DEFAULT_NR_STRUCT_FIELDS); |
| 83 | variant_type->scope = new_type_scope(parent_scope); |
| 84 | type->id = CTF_TYPE_VARIANT; |
| 85 | type->name = g_quark_from_string(name); |
| 86 | type->alignment = 1; |
| 87 | type->copy = variant_copy; |
| 88 | type->type_free = _variant_type_free; |
| 89 | type->declaration_new = _variant_declaration_new; |
| 90 | type->declaration_free = _variant_declaration_free; |
| 91 | type->ref = 1; |
| 92 | return variant_type; |
| 93 | } |
| 94 | |
| 95 | static |
| 96 | struct declaration * |
| 97 | _variant_declaration_new(struct type *type, |
| 98 | struct declaration_scope *parent_scope) |
| 99 | { |
| 100 | struct type_variant *variant_type = |
| 101 | container_of(type, struct type_variant, p); |
| 102 | struct declaration_variant *variant; |
| 103 | unsigned long i; |
| 104 | |
| 105 | variant = g_new(struct declaration_variant, 1); |
| 106 | type_ref(&variant_type->p); |
| 107 | variant->p.type = type; |
| 108 | variant->type = variant_type; |
| 109 | variant->p.ref = 1; |
| 110 | variant->scope = new_declaration_scope(parent_scope); |
| 111 | variant->fields = g_array_sized_new(FALSE, TRUE, |
| 112 | sizeof(struct field), |
| 113 | DEFAULT_NR_STRUCT_FIELDS); |
| 114 | g_array_set_size(variant->fields, variant_type->fields->len); |
| 115 | for (i = 0; i < variant_type->fields->len; i++) { |
| 116 | struct type_field *type_field = |
| 117 | &g_array_index(variant_type->fields, |
| 118 | struct type_field, i); |
| 119 | struct field *field = &g_array_index(variant->fields, |
| 120 | struct field, i); |
| 121 | |
| 122 | field->name = type_field->name; |
| 123 | field->declaration = |
| 124 | type_field->type->declaration_new(type_field->type, |
| 125 | variant->scope); |
| 126 | } |
| 127 | variant->current_field = NULL; |
| 128 | return &variant->p; |
| 129 | } |
| 130 | |
| 131 | static |
| 132 | void _variant_declaration_free(struct declaration *declaration) |
| 133 | { |
| 134 | struct declaration_variant *variant = |
| 135 | container_of(declaration, struct declaration_variant, p); |
| 136 | unsigned long i; |
| 137 | |
| 138 | assert(variant->fields->len == variant->type->fields->len); |
| 139 | for (i = 0; i < variant->fields->len; i++) { |
| 140 | struct field *field = &g_array_index(variant->fields, |
| 141 | struct field, i); |
| 142 | declaration_unref(field->declaration); |
| 143 | } |
| 144 | free_declaration_scope(variant->scope); |
| 145 | type_unref(variant->p.type); |
| 146 | g_free(variant); |
| 147 | } |
| 148 | |
| 149 | void variant_type_add_field(struct type_variant *variant_type, |
| 150 | const char *tag_name, |
| 151 | struct type *tag_type) |
| 152 | { |
| 153 | struct type_field *field; |
| 154 | unsigned long index; |
| 155 | |
| 156 | g_array_set_size(variant_type->fields, variant_type->fields->len + 1); |
| 157 | index = variant_type->fields->len - 1; /* last field (new) */ |
| 158 | field = &g_array_index(variant_type->fields, struct type_field, index); |
| 159 | field->name = g_quark_from_string(tag_name); |
| 160 | type_ref(tag_type); |
| 161 | field->type = tag_type; |
| 162 | /* Keep index in hash rather than pointer, because array can relocate */ |
| 163 | g_hash_table_insert(variant_type->fields_by_tag, |
| 164 | (gpointer) (unsigned long) field->name, |
| 165 | (gpointer) index); |
| 166 | /* |
| 167 | * Alignment of variant is based on the alignment of its currently |
| 168 | * selected choice, so we leave variant alignment as-is (statically |
| 169 | * speaking). |
| 170 | */ |
| 171 | } |
| 172 | |
| 173 | struct type_field * |
| 174 | struct_type_get_field_from_tag(struct type_variant *variant_type, GQuark tag) |
| 175 | { |
| 176 | unsigned long index; |
| 177 | |
| 178 | index = (unsigned long) g_hash_table_lookup(variant_type->fields_by_tag, |
| 179 | (gconstpointer) (unsigned long) tag); |
| 180 | return &g_array_index(variant_type->fields, struct type_field, index); |
| 181 | } |
| 182 | |
| 183 | /* |
| 184 | * tag_instance is assumed to be an enumeration. |
| 185 | */ |
| 186 | int variant_declaration_set_tag(struct declaration_variant *variant, |
| 187 | struct declaration *enum_tag) |
| 188 | { |
| 189 | struct declaration_enum *_enum = |
| 190 | container_of(variant->enum_tag, struct declaration_enum, p); |
| 191 | struct type_enum *enum_type = _enum->type; |
| 192 | int missing_field = 0; |
| 193 | unsigned long i; |
| 194 | |
| 195 | /* |
| 196 | * Strictly speaking, each enumerator must map to a field of the |
| 197 | * variant. However, we are even stricter here by requiring that each |
| 198 | * variant choice map to an enumerator too. We then validate that the |
| 199 | * number of enumerators equals the number of variant choices. |
| 200 | */ |
| 201 | if (variant->type->fields->len != enum_get_nr_enumerators(enum_type)) |
| 202 | return -EPERM; |
| 203 | |
| 204 | for (i = 0; i < variant->type->fields->len; i++) { |
| 205 | struct type_field *field_type = |
| 206 | &g_array_index(variant->type->fields, |
| 207 | struct type_field, i); |
| 208 | if (!enum_quark_to_range_set(enum_type, field_type->name)) { |
| 209 | missing_field = 1; |
| 210 | break; |
| 211 | } |
| 212 | } |
| 213 | if (missing_field) |
| 214 | return -EPERM; |
| 215 | |
| 216 | /* |
| 217 | * Check the enumeration: it must map each value to one and only one |
| 218 | * enumerator tag. |
| 219 | * TODO: we should also check that each range map to one and only one |
| 220 | * tag. For the moment, we will simply check this dynamically in |
| 221 | * variant_type_get_current_field(). |
| 222 | */ |
| 223 | |
| 224 | /* Set the enum tag field */ |
| 225 | variant->enum_tag = enum_tag; |
| 226 | return 0; |
| 227 | } |
| 228 | |
| 229 | /* |
| 230 | * field returned only valid as long as the field structure is not appended to. |
| 231 | */ |
| 232 | struct field *variant_get_current_field(struct declaration_variant *variant) |
| 233 | { |
| 234 | struct declaration_enum *_enum = |
| 235 | container_of(variant->enum_tag, struct declaration_enum, p); |
| 236 | struct type_variant *variant_type = variant->type; |
| 237 | unsigned long index; |
| 238 | GArray *tag_array; |
| 239 | GQuark tag; |
| 240 | |
| 241 | tag_array = _enum->value; |
| 242 | /* |
| 243 | * The 1 to 1 mapping from enumeration to value should have been already |
| 244 | * checked. (see TODO above) |
| 245 | */ |
| 246 | assert(tag_array->len == 1); |
| 247 | tag = g_array_index(tag_array, GQuark, 0); |
| 248 | index = (unsigned long) g_hash_table_lookup(variant_type->fields_by_tag, |
| 249 | (gconstpointer) (unsigned long) tag); |
| 250 | variant->current_field = &g_array_index(variant->fields, struct field, index); |
| 251 | return variant->current_field; |
| 252 | } |