class for referring to definitions of variables or record fields

src/script_opt/DefItem.cc

@@ -0,0 +1,154 @@
+// See the file "COPYING" in the main distribution directory for copyright.
+
+#include "DefItem.h"
+#include "Expr.h"
+
+
+namespace zeek::detail {
+
+
+DefinitionItem::DefinitionItem(const ID* _id)
+: name(_id->Name())
+	{
+	is_id = true;
+	id = _id;
+	di = nullptr;
+	field_name = nullptr;
+
+	t = id->GetType();
+
+	CheckForRecord();
+	}
+
+DefinitionItem::DefinitionItem(const DefinitionItem* _di,
+				const char* _field_name, TypePtr _t)
+	{
+	is_id = false;
+	id = nullptr;
+	di = _di;
+	field_name = _field_name;
+
+	t = std::move(_t);
+
+	name += di->Name();
+	name += '$';
+	name += field_name;
+
+	CheckForRecord();
+	}
+
+std::shared_ptr<DefinitionItem>
+DefinitionItem::FindField(const char* field) const
+	{
+	if ( ! IsRecord() )
+		return nullptr;
+
+	auto offset = rt->FieldOffset(field);
+
+	return FindField(offset);
+	}
+
+std::shared_ptr<DefinitionItem> DefinitionItem::FindField(int offset) const
+	{
+	if ( ! IsRecord() )
+		return nullptr;
+
+	return (*fields)[offset];
+	}
+
+std::shared_ptr<DefinitionItem>
+DefinitionItem::CreateField(const char* field, TypePtr t)
+	{
+	auto offset = rt->FieldOffset(field);
+
+	if ( (*fields)[offset] )
+		return (*fields)[offset];
+
+	(*fields)[offset] =
+		std::make_shared<DefinitionItem>(this, field, std::move(t));
+
+	return (*fields)[offset];
+	}
+
+std::shared_ptr<DefinitionItem>
+DefinitionItem::CreateField(int offset, TypePtr t)
+	{
+	if ( (*fields)[offset] )
+		return (*fields)[offset];
+
+	auto field = rt->FieldName(offset);
+
+	(*fields)[offset] =
+		std::make_shared<DefinitionItem>(this, field, std::move(t));
+
+	return (*fields)[offset];
+	}
+
+void DefinitionItem::CheckForRecord()
+	{
+	if ( ! IsRecord() )
+		{
+		rt = nullptr;
+		return;
+		}
+
+	rt = t->AsRecordType();
+	num_fields = rt->NumFields();
+	fields = std::vector<std::shared_ptr<DefinitionItem>>(num_fields);
+	}
+
+
+std::shared_ptr<DefinitionItem> DefItemMap::GetExprDI(const Expr* expr)
+	{
+	if ( expr->Tag() == EXPR_NAME )
+		{
+		auto id_e = expr->AsNameExpr();
+		auto id = id_e->Id();
+		return GetID_DI(id);
+		}
+
+	else if ( expr->Tag() == EXPR_FIELD )
+		{
+		auto f = expr->AsFieldExpr();
+		auto r = f->Op();
+
+		auto r_def = GetExprDI(r);
+
+		if ( ! r_def )
+			return nullptr;
+
+		auto field = f->FieldName();
+		return r_def->FindField(field);
+		}
+
+	else
+		return nullptr;
+	}
+
+std::shared_ptr<DefinitionItem> DefItemMap::GetID_DI(const ID* id)
+	{
+	auto di = i2d.find(id);
+	if ( di == i2d.end() )
+		{
+		auto new_entry = std::make_shared<DefinitionItem>(id);
+		i2d[id] = new_entry;
+		return new_entry;
+		}
+	else
+		return di->second;
+	}
+
+const DefinitionItem* DefItemMap::GetConstID_DI(const ID* id) const
+	{
+	auto di = i2d.find(id);
+	return di == i2d.end() ? nullptr : di->second.get();
+	}
+
+const DefinitionItem* DefItemMap::GetConstID_DI(const DefinitionItem* di,
+						const char* field_name) const
+	{
+	return di->FindField(field_name).get();
+	}
+
+
+} // zeek::detail