| 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 | |
| 22 | |
| 23 | static |
| 24 | struct type *variant_type_new(struct type_class *type_class, |
| 25 | struct declaration_scope *parent_scope); |
| 26 | static |
| 27 | void variant_type_free(struct type *type); |
| 28 | |
| 29 | void variant_copy(struct stream_pos *dest, const struct format *fdest, |
| 30 | struct stream_pos *src, const struct format *fsrc, |
| 31 | struct type *type) |
| 32 | { |
| 33 | struct type_variant *variant = container_of(type, struct type_variant, |
| 34 | p); |
| 35 | struct type_class_variant *variant_class = variant->_class; |
| 36 | struct field *field; |
| 37 | struct type_class *field_class; |
| 38 | unsigned long i; |
| 39 | |
| 40 | fsrc->variant_begin(src, variant_class); |
| 41 | fdest->variant_begin(dest, variant_class); |
| 42 | |
| 43 | field = variant_type_get_current_field(variant); |
| 44 | field_class = field->type->p._class; |
| 45 | field_class->copy(dest, fdest, src, fsrc, &field->type->p); |
| 46 | |
| 47 | fsrc->variant_end(src, variant_class); |
| 48 | fdest->variant_end(dest, variant_class); |
| 49 | } |
| 50 | |
| 51 | static |
| 52 | void variant_type_class_free(struct type_class *type_class) |
| 53 | { |
| 54 | struct type_class_variant *variant_class = |
| 55 | container_of(type_class, struct type_class_variant, p); |
| 56 | unsigned long i; |
| 57 | |
| 58 | g_hash_table_destroy(struct_class->fields_by_tag); |
| 59 | |
| 60 | for (i = 0; i < variant_class->fields->len; i++) { |
| 61 | struct field *type_class_field = |
| 62 | &g_array_index(variant_class->fields, |
| 63 | struct type_class_field, i); |
| 64 | type_class_unref(field->type_class); |
| 65 | } |
| 66 | g_array_free(variant_class->fields, true); |
| 67 | g_free(variant_class); |
| 68 | } |
| 69 | |
| 70 | struct type_class_variant * |
| 71 | variant_type_class_new(const char *name) |
| 72 | { |
| 73 | struct type_class_variant *variant_class; |
| 74 | struct type_class *type_class; |
| 75 | int ret; |
| 76 | |
| 77 | variant_class = g_new(struct type_class_variant, 1); |
| 78 | type_class = &variant_class->p; |
| 79 | variant_class->fields_by_tag = g_hash_table_new(g_direct_hash, |
| 80 | g_direct_equal); |
| 81 | variant_class->fields = g_array_sized_new(FALSE, TRUE, |
| 82 | sizeof(struct type_class_field), |
| 83 | DEFAULT_NR_STRUCT_FIELDS); |
| 84 | type_class->name = g_quark_from_string(name); |
| 85 | type_class->alignment = 1; |
| 86 | type_class->copy = variant_copy; |
| 87 | type_class->class_free = _variant_type_class_free; |
| 88 | type_class->type_new = _variant_type_new; |
| 89 | type_class->type_free = _variant_type_free; |
| 90 | type_class->ref = 1; |
| 91 | |
| 92 | if (type_class->name) { |
| 93 | ret = register_type(type_class); |
| 94 | if (ret) |
| 95 | goto error_register; |
| 96 | } |
| 97 | return struct_class; |
| 98 | |
| 99 | error_register: |
| 100 | g_hash_table_destroy(variant_class->fields_by_tag); |
| 101 | g_array_free(variant_class->fields, true); |
| 102 | g_free(variant_class); |
| 103 | return NULL; |
| 104 | } |
| 105 | |
| 106 | static |
| 107 | struct type_variant *_variant_type_new(struct type_class *type_class, |
| 108 | struct declaration_scope *parent_scope) |
| 109 | { |
| 110 | struct type_class_variant *variant_class = |
| 111 | container_of(type_class, struct type_class_variant, p); |
| 112 | struct type_struct *variant; |
| 113 | |
| 114 | variant = g_new(struct type_variant, 1); |
| 115 | type_class_ref(&variant_class->p); |
| 116 | variant->p._class = variant_class; |
| 117 | variant->p.ref = 1; |
| 118 | variant->scope = new_declaration_scope(parent_scope); |
| 119 | variant->fields = g_array_sized_new(FALSE, TRUE, |
| 120 | sizeof(struct field), |
| 121 | DEFAULT_NR_STRUCT_FIELDS); |
| 122 | variant->current_field = NULL; |
| 123 | return &variant->p; |
| 124 | } |
| 125 | |
| 126 | static |
| 127 | void variant_type_free(struct type *type) |
| 128 | { |
| 129 | struct type_variant *variant = container_of(type, struct type_variant, |
| 130 | p); |
| 131 | unsigned long i; |
| 132 | |
| 133 | for (i = 0; i < variant->fields->len; i++) { |
| 134 | struct field *field = &g_array_index(variant->fields, |
| 135 | struct field, i); |
| 136 | type_unref(field->type); |
| 137 | } |
| 138 | free_declaration_scope(variant->scope); |
| 139 | type_class_unref(variant->p._class); |
| 140 | g_free(variant); |
| 141 | } |
| 142 | |
| 143 | void variant_type_class_add_field(struct type_class_variant *variant_class, |
| 144 | const char *tag_name, |
| 145 | struct type_class *type_class) |
| 146 | { |
| 147 | struct type_class_field *field; |
| 148 | unsigned long index; |
| 149 | |
| 150 | g_array_set_size(variant_class->fields, variant_class->fields->len + 1); |
| 151 | index = variant_class->fields->len - 1; /* last field (new) */ |
| 152 | field = &g_array_index(variant_class->fields, struct type_class_field, index); |
| 153 | field->name = g_quark_from_string(tag_name); |
| 154 | type_ref(type_class); |
| 155 | field->type_class = type_class; |
| 156 | /* Keep index in hash rather than pointer, because array can relocate */ |
| 157 | g_hash_table_insert(variant_class->fields_by_name, |
| 158 | (gpointer) (unsigned long) field->name, |
| 159 | (gpointer) index); |
| 160 | /* |
| 161 | * Alignment of variant is based on the alignment of its currently |
| 162 | * selected choice, so we leave variant alignment as-is (statically |
| 163 | * speaking). |
| 164 | */ |
| 165 | } |
| 166 | |
| 167 | struct type_class_field * |
| 168 | struct_type_class_get_field_from_tag(struct type_class_variant *variant_class, |
| 169 | GQuark tag) |
| 170 | { |
| 171 | unsigned long index; |
| 172 | |
| 173 | index = (unsigned long) g_hash_table_lookup(variant_class->fields_by_tag, |
| 174 | (gconstpointer) (unsigned long) tag); |
| 175 | return &g_array_index(variant_class->fields, struct type_class_field, index); |
| 176 | } |
| 177 | |
| 178 | /* |
| 179 | * tag_instance is assumed to be an enumeration. |
| 180 | */ |
| 181 | int variant_type_set_tag(struct type_variant *variant, |
| 182 | struct type *enum_tag_instance) |
| 183 | { |
| 184 | struct type_enum *_enum = |
| 185 | container_of(struct type_enum, variant->enum_tag, p); |
| 186 | struct type_class_enum *enum_class = _enum->_class; |
| 187 | int missing_field = 0; |
| 188 | unsigned long i; |
| 189 | |
| 190 | /* |
| 191 | * Strictly speaking, each enumerator must map to a field of the |
| 192 | * variant. However, we are even stricter here by requiring that each |
| 193 | * variant choice map to an enumerator too. We then validate that the |
| 194 | * number of enumerators equals the number of variant choices. |
| 195 | */ |
| 196 | if (variant->_class->fields->len != enum_get_nr_enumerators(enum_class)) |
| 197 | return -EPERM; |
| 198 | |
| 199 | for (i = 0; i < variant->_class->fields->len; i++) { |
| 200 | struct type_class_field *field_class = |
| 201 | &g_array_index(variant->_class->fields, |
| 202 | struct type_class_field, i); |
| 203 | if (!enum_quark_to_range_set(enum_class, field_class->name)) { |
| 204 | missing_field = 1; |
| 205 | break; |
| 206 | } |
| 207 | } |
| 208 | if (missing_field) |
| 209 | return -EPERM; |
| 210 | |
| 211 | /* |
| 212 | * Check the enumeration: it must map each value to one and only one |
| 213 | * enumerator tag. |
| 214 | * TODO: we should also check that each range map to one and only one |
| 215 | * tag. For the moment, we will simply check this dynamically in |
| 216 | * variant_type_get_current_field(). |
| 217 | */ |
| 218 | |
| 219 | /* Set the enum tag field */ |
| 220 | variant->enum_tag = enum_tag_instance; |
| 221 | return 0; |
| 222 | } |
| 223 | |
| 224 | /* |
| 225 | * field returned only valid as long as the field structure is not appended to. |
| 226 | */ |
| 227 | struct field * |
| 228 | variant_type_get_current_field(struct type_variant *variant) |
| 229 | { |
| 230 | struct type_enum *_enum = |
| 231 | container_of(struct type_enum, variant->enum_tag, p); |
| 232 | struct variat_type_class *variant_class = variant->_class; |
| 233 | unsigned long index; |
| 234 | GArray *tag_array; |
| 235 | GQuark tag; |
| 236 | |
| 237 | tag_array = _enum->value; |
| 238 | /* |
| 239 | * The 1 to 1 mapping from enumeration to value should have been already |
| 240 | * checked. (see TODO above) |
| 241 | */ |
| 242 | assert(tag_array->len == 1); |
| 243 | tag = g_array_index(tag_array, GQuark, 0); |
| 244 | index = (unsigned long) g_hash_table_lookup(variant_class->fields_by_tag, |
| 245 | (gconstpointer) (unsigned long) tag); |
| 246 | variant->current_field = &g_array_index(variant_class->fields, struct field, index); |
| 247 | return variant->current_field; |
| 248 | } |