move find_union_tag from check-structures-sanity to DataDefs.h

library/DataDefs.cpp

@@ -454,3 +454,90 @@ void DFHack::flagarrayToString(std::vector<std::string> *pvec, const void *p,
         }
     }
 }
+
+static const struct_field_info *find_union_tag_candidate(const struct_field_info *fields, const struct_field_info *union_field)
+{
+    std::string name(union_field->name);
+    if (name.length() >= 4 && name.substr(name.length() - 4) == "data")
+    {
+        name.erase(name.length() - 4, 4);
+        name += "type";
+
+        for (auto field = fields; field->mode != struct_field_info::END; field++)
+        {
+            if (field->name == name)
+            {
+                return field;
+            }
+        }
+    }
+
+    if (name.length() > 7 &&
+            name.substr(name.length() - 7) == "_target" &&
+            fields != union_field &&
+            (union_field - 1)->name == name.substr(0, name.length() - 7))
+    {
+        return union_field - 1;
+    }
+
+    return union_field + 1;
+}
+
+const struct_field_info *DFHack::find_union_tag(const struct_field_info *fields, const struct_field_info *union_field)
+{
+    CHECK_NULL_POINTER(fields);
+    CHECK_NULL_POINTER(union_field);
+
+    auto tag_candidate = find_union_tag_candidate(fields, union_field);
+
+    if (union_field->mode == struct_field_info::SUBSTRUCT &&
+            union_field->type &&
+            union_field->type->type() == IDTYPE_UNION)
+    {
+        // union field
+
+        if (tag_candidate->mode == struct_field_info::PRIMITIVE &&
+                tag_candidate->type &&
+                tag_candidate->type->type() == IDTYPE_ENUM)
+        {
+            return tag_candidate;
+        }
+
+        return nullptr;
+    }
+
+    if (union_field->mode != struct_field_info::CONTAINER ||
+            !union_field->type ||
+            union_field->type->type() != IDTYPE_CONTAINER)
+    {
+        // not a union field or a vector; bail
+        return nullptr;
+    }
+
+    auto container_type = static_cast<container_identity *>(union_field->type);
+    if (container_type->getFullName(nullptr) != "vector<void>" ||
+            !container_type->getItemType() ||
+            container_type->getItemType()->type() != IDTYPE_UNION)
+    {
+        // not a vector of unions
+        return nullptr;
+    }
+
+    if (tag_candidate->mode != struct_field_info::CONTAINER ||
+            !tag_candidate->type ||
+            tag_candidate->type->type() != IDTYPE_CONTAINER)
+    {
+        // candidate is not a vector
+        return nullptr;
+    }
+
+    auto tag_container_type = static_cast<container_identity *>(tag_candidate->type);
+    if (tag_container_type->getFullName(nullptr) == "vector<void>" &&
+            tag_container_type->getItemType() &&
+            tag_container_type->getItemType()->type() == IDTYPE_ENUM)
+    {
+        return tag_candidate;
+    }
+
+    return nullptr;
+}

library/include/DataDefs.h

@@ -796,6 +796,16 @@ namespace DFHack {
         flagarray_to_string<T>(&tmp, val);
         return join_strings(sep, tmp);
     }
+
+    /**
+     * Finds the tag field for a given union field.
+     *
+     * The returned tag field is a primitive enum field or nullptr.
+     *
+     * If the union field is a container type, the returned tag field is
+     * a container of primitive enum types.
+     */
+    DFHACK_EXPORT const struct_field_info *find_union_tag(const struct_field_info *fields, const struct_field_info *union_field);
 }
 
 #define ENUM_ATTR(enum,attr,val) (df::enum_traits<df::enum>::attrs(val).attr)

plugins/devel/check-structures-sanity.cpp

@@ -97,97 +97,6 @@ static const char *const *get_enum_item_key(enum_identity *identity, int64_t val
     return &identity->getKeys()[index];
 }
 
-static const struct_field_info *find_union_tag_field(const struct_field_info *fields, const struct_field_info *union_field)
-{
-    std::string name(union_field->name);
-    if (name.length() >= 4 && name.substr(name.length() - 4) == "data")
-    {
-        name.erase(name.length() - 4, 4);
-        name += "type";
-
-        for (auto field = fields; field->mode != struct_field_info::END; field++)
-        {
-            if (field->name == name)
-            {
-                return field;
-            }
-        }
-    }
-
-    if (name.length() > 7 &&
-            name.substr(name.length() - 7) == "_target" &&
-            fields != union_field &&
-            (union_field - 1)->name == name.substr(0, name.length() - 7))
-    {
-        return union_field - 1;
-    }
-
-    return union_field + 1;
-}
-
-static const struct_field_info *find_union_tag(const struct_field_info *fields, const struct_field_info *union_field)
-{
-    if (union_field->mode != struct_field_info::SUBSTRUCT ||
-            !union_field->type ||
-            union_field->type->type() != IDTYPE_UNION)
-    {
-        // not a union
-        return nullptr;
-    }
-
-
-    const struct_field_info *tag_field = find_union_tag_field(fields, union_field);
-    if (tag_field->mode != struct_field_info::PRIMITIVE ||
-            !tag_field->type ||
-            tag_field->type->type() != IDTYPE_ENUM)
-    {
-        // no tag
-        return nullptr;
-    }
-
-    return tag_field;
-}
-
-static const struct_field_info *find_union_vector_tag_vector(const struct_field_info *fields, const struct_field_info *union_field)
-{
-    if (union_field->mode != struct_field_info::CONTAINER ||
-            !union_field->type ||
-            union_field->type->type() != IDTYPE_CONTAINER)
-    {
-        // not a vector
-        return nullptr;
-    }
-
-    auto container_type = static_cast<container_identity *>(union_field->type);
-    if (container_type->getFullName(nullptr) != "vector<void>" ||
-            !container_type->getItemType() ||
-            container_type->getItemType()->type() != IDTYPE_UNION)
-    {
-        // not a union
-        return nullptr;
-    }
-
-    const struct_field_info *tag_field = find_union_tag_field(fields, union_field);
-    if (tag_field->mode != struct_field_info::CONTAINER ||
-            !tag_field->type ||
-            tag_field->type->type() != IDTYPE_CONTAINER)
-    {
-        // no tag vector
-        return nullptr;
-    }
-
-    auto tag_container_type = static_cast<container_identity *>(tag_field->type);
-    if (tag_container_type->getFullName(nullptr) != "vector<void>" ||
-            !tag_container_type->getItemType() ||
-            tag_container_type->getItemType()->type() != IDTYPE_ENUM)
-    {
-        // not an enum
-        return nullptr;
-    }
-
-    return tag_field;
-}
-
 struct ToCheck
 {
     std::vector<std::string> path;
@@ -693,27 +602,18 @@ void Checker::queue_static_array(const ToCheck & array, void *base, type_identit
 bool Checker::maybe_queue_union(const ToCheck & item, const struct_field_info *fields, const struct_field_info *union_field)
 {
     auto tag_field = find_union_tag(fields, union_field);
-    if (tag_field)
+    if (!tag_field)
-    {
+        return false;
-        ToCheck union_item(item, "." + std::string(union_field->name), PTR_ADD(item.ptr, union_field->offset), union_field->type);
-        ToCheck tag_item(item, "." + std::string(tag_field->name), PTR_ADD(item.ptr, tag_field->offset), tag_field->type);
-        queue_union(union_item, tag_item);
-
-        return true;
-    }
-
-    tag_field = find_union_vector_tag_vector(fields, union_field);
-    if (tag_field)
-    {
-        ToCheck union_vector_item(item, "." + std::string(union_field->name), PTR_ADD(item.ptr, union_field->offset), union_field->type);
-        ToCheck tag_vector_item(item, "." + std::string(tag_field->name), PTR_ADD(item.ptr, tag_field->offset), tag_field->type);
 
-        queue_union_vector(union_vector_item, tag_vector_item);
+    ToCheck union_item(item, "." + std::string(union_field->name), PTR_ADD(item.ptr, union_field->offset), union_field->type);
+    ToCheck tag_item(item, "." + std::string(tag_field->name), PTR_ADD(item.ptr, tag_field->offset), tag_field->type);
 
-        return true;
+    if (union_field->mode == struct_field_info::SUBSTRUCT)
-    }
+        queue_union(union_item, tag_item);
+    else
+        queue_union_vector(union_item, tag_item);
 
-    return false;
+    return true;
 }
 
 void Checker::queue_union(const ToCheck & item, const ToCheck & tag_item)