+/*
+ * variant.c
+ *
+ * BabelTrace - Variant Type Converter
+ *
+ * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ */
+
+#include <babeltrace/compiler.h>
+#include <babeltrace/format.h>
+
+
+static
+struct type *variant_type_new(struct type_class *type_class,
+ struct declaration_scope *parent_scope);
+static
+void variant_type_free(struct type *type);
+
+void variant_copy(struct stream_pos *dest, const struct format *fdest,
+ struct stream_pos *src, const struct format *fsrc,
+ struct type *type)
+{
+ struct type_variant *variant = container_of(type, struct type_variant,
+ p);
+ struct type_class_variant *variant_class = variant->_class;
+ struct field *field;
+ struct type_class *field_class;
+ unsigned long i;
+
+ fsrc->variant_begin(src, variant_class);
+ fdest->variant_begin(dest, variant_class);
+
+ field = variant_type_get_current_field(variant);
+ field_class = field->type->p._class;
+ field_class->copy(dest, fdest, src, fsrc, &field->type->p);
+
+ fsrc->variant_end(src, variant_class);
+ fdest->variant_end(dest, variant_class);
+}
+
+static
+void variant_type_class_free(struct type_class *type_class)
+{
+ struct type_class_variant *variant_class =
+ container_of(type_class, struct type_class_variant, p);
+ unsigned long i;
+
+ g_hash_table_destroy(struct_class->fields_by_tag);
+
+ for (i = 0; i < variant_class->fields->len; i++) {
+ struct field *type_class_field =
+ &g_array_index(variant_class->fields,
+ struct type_class_field, i);
+ type_class_unref(field->type_class);
+ }
+ g_array_free(variant_class->fields, true);
+ g_free(variant_class);
+}
+
+struct type_class_variant *
+variant_type_class_new(const char *name)
+{
+ struct type_class_variant *variant_class;
+ struct type_class *type_class;
+ int ret;
+
+ variant_class = g_new(struct type_class_variant, 1);
+ type_class = &variant_class->p;
+ variant_class->fields_by_tag = g_hash_table_new(g_direct_hash,
+ g_direct_equal);
+ variant_class->fields = g_array_sized_new(FALSE, TRUE,
+ sizeof(struct type_class_field),
+ DEFAULT_NR_STRUCT_FIELDS);
+ type_class->name = g_quark_from_string(name);
+ type_class->alignment = 1;
+ type_class->copy = variant_copy;
+ type_class->class_free = _variant_type_class_free;
+ type_class->type_new = _variant_type_new;
+ type_class->type_free = _variant_type_free;
+ type_class->ref = 1;
+
+ if (type_class->name) {
+ ret = register_type(type_class);
+ if (ret)
+ goto error_register;
+ }
+ return struct_class;
+
+error_register:
+ g_hash_table_destroy(variant_class->fields_by_tag);
+ g_array_free(variant_class->fields, true);
+ g_free(variant_class);
+ return NULL;
+}
+
+static
+struct type_variant *_variant_type_new(struct type_class *type_class,
+ struct declaration_scope *parent_scope)
+{
+ struct type_class_variant *variant_class =
+ container_of(type_class, struct type_class_variant, p);
+ struct type_struct *variant;
+
+ variant = g_new(struct type_variant, 1);
+ type_class_ref(&variant_class->p);
+ variant->p._class = variant_class;
+ variant->p.ref = 1;
+ variant->scope = new_declaration_scope(parent_scope);
+ variant->fields = g_array_sized_new(FALSE, TRUE,
+ sizeof(struct field),
+ DEFAULT_NR_STRUCT_FIELDS);
+ variant->current_field = NULL;
+ return &variant->p;
+}
+
+static
+void variant_type_free(struct type *type)
+{
+ struct type_variant *variant = container_of(type, struct type_variant,
+ p);
+ unsigned long i;
+
+ for (i = 0; i < variant->fields->len; i++) {
+ struct field *field = &g_array_index(variant->fields,
+ struct field, i);
+ type_unref(field->type);
+ }
+ free_declaration_scope(variant->scope);
+ type_class_unref(variant->p._class);
+ g_free(variant);
+}
+
+void variant_type_class_add_field(struct type_class_variant *variant_class,
+ const char *tag_name,
+ struct type_class *type_class)
+{
+ struct type_class_field *field;
+ unsigned long index;
+
+ g_array_set_size(variant_class->fields, variant_class->fields->len + 1);
+ index = variant_class->fields->len - 1; /* last field (new) */
+ field = &g_array_index(variant_class->fields, struct type_class_field, index);
+ field->name = g_quark_from_string(tag_name);
+ type_ref(type_class);
+ field->type_class = type_class;
+ /* Keep index in hash rather than pointer, because array can relocate */
+ g_hash_table_insert(variant_class->fields_by_name,
+ (gpointer) (unsigned long) field->name,
+ (gpointer) index);
+ /*
+ * Alignment of variant is based on the alignment of its currently
+ * selected choice, so we leave variant alignment as-is (statically
+ * speaking).
+ */
+}
+
+struct type_class_field *
+struct_type_class_get_field_from_tag(struct type_class_variant *variant_class,
+ GQuark tag)
+{
+ unsigned long index;
+
+ index = (unsigned long) g_hash_table_lookup(variant_class->fields_by_tag,
+ (gconstpointer) (unsigned long) tag);
+ return &g_array_index(variant_class->fields, struct type_class_field, index);
+}
+
+/*
+ * tag_instance is assumed to be an enumeration.
+ */
+int variant_type_set_tag(struct type_variant *variant,
+ struct type *enum_tag_instance)
+{
+ struct type_enum *_enum =
+ container_of(struct type_enum, variant->enum_tag, p);
+ struct type_class_enum *enum_class = _enum->_class;
+ int missing_field = 0;
+ unsigned long i;
+
+ /*
+ * Strictly speaking, each enumerator must map to a field of the
+ * variant. However, we are even stricter here by requiring that each
+ * variant choice map to an enumerator too. We then validate that the
+ * number of enumerators equals the number of variant choices.
+ */
+ if (variant->_class->fields->len != enum_get_nr_enumerators(enum_class))
+ return -EPERM;
+
+ for (i = 0; i < variant->_class->fields->len; i++) {
+ struct type_class_field *field_class =
+ &g_array_index(variant->_class->fields,
+ struct type_class_field, i);
+ if (!enum_quark_to_range_set(enum_class, field_class->name)) {
+ missing_field = 1;
+ break;
+ }
+ }
+ if (missing_field)
+ return -EPERM;
+
+ /*
+ * Check the enumeration: it must map each value to one and only one
+ * enumerator tag.
+ * TODO: we should also check that each range map to one and only one
+ * tag. For the moment, we will simply check this dynamically in
+ * variant_type_get_current_field().
+ */
+
+ /* Set the enum tag field */
+ variant->enum_tag = enum_tag_instance;
+ return 0;
+}
+
+/*
+ * field returned only valid as long as the field structure is not appended to.
+ */
+struct field *
+variant_type_get_current_field(struct type_variant *variant)
+{
+ struct type_enum *_enum =
+ container_of(struct type_enum, variant->enum_tag, p);
+ struct variat_type_class *variant_class = variant->_class;
+ unsigned long index;
+ GArray *tag_array;
+ GQuark tag;
+
+ tag_array = _enum->value;
+ /*
+ * The 1 to 1 mapping from enumeration to value should have been already
+ * checked. (see TODO above)
+ */
+ assert(tag_array->len == 1);
+ tag = g_array_index(tag_array, GQuark, 0);
+ index = (unsigned long) g_hash_table_lookup(variant_class->fields_by_tag,
+ (gconstpointer) (unsigned long) tag);
+ return &g_array_index(variant_class->fields, struct field, index);
+}