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c054553d MD |
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); | |
96354dac MD |
246 | variant->current_field = &g_array_index(variant_class->fields, struct field, index); |
247 | return variant->current_field; | |
c054553d | 248 | } |