root/ROOT/RFieldUtils.hxx

0001 /// \file RFieldUtils.hxx
0002 /// \ingroup NTuple
0003 /// \author Jonas Hahnfeld <jonas.hahnfeld@cern.ch>
0004 /// \date 2024-11-19
0005
0006 #ifndef ROOT_RFieldUtils
0007 #define ROOT_RFieldUtils
0008
0009 #include <string>
0010 #include <string_view>
0011 #include <typeinfo>
0012 #include <tuple>
0013 #include <vector>
0014
0015 class TClass;
0016
0017 namespace ROOT {
0018
0019 class RFieldBase;
0020 class RNTupleDescriptor;
0021
0022 namespace Internal {
0023
0024 /// Applies RNTuple specific type name normalization rules (see specs) that help the string parsing in
0025 /// RFieldBase::Create(). The normalization of templated types does not include full normalization of the
0026 /// template arguments (hence "Prefix").
0027 /// Furthermore, if the type is a C-style array, rules are applied to the base type and the C style array
0028 /// is then mapped to an std::array.
0029 std::string GetCanonicalTypePrefix(const std::string &typeName);
0030
0031 /// Given a type name normalized by ROOT meta, renormalize it for RNTuple. E.g., insert std::prefix.
0032 std::string GetRenormalizedTypeName(const std::string &metaNormalizedName);
0033
0034 /// Given a type info ask ROOT meta to demangle it, then renormalize the resulting type name for RNTuple. Useful to
0035 /// ensure that e.g. fundamental types are normalized to the type used by RNTuple (e.g. int -> std::int32_t).
0036 std::string GetRenormalizedTypeName(const std::type_info &ti);
0037
0038 /// Applies all RNTuple type normalization rules except typedef resolution.
0039 std::string GetNormalizedUnresolvedTypeName(const std::string &origName);
0040
0041 /// Appends 'll' or 'ull' to the where necessary and strips the suffix if not needed.
0042 std::string GetNormalizedInteger(const std::string &intTemplateArg);
0043 std::string GetNormalizedInteger(long long val);
0044 std::string GetNormalizedInteger(unsigned long long val);
0045 long long ParseIntTypeToken(const std::string &intToken);
0046 unsigned long long ParseUIntTypeToken(const std::string &uintToken);
0047
0048 /// Possible settings for the "rntuple.streamerMode" class attribute in the dictionary.
0049 enum class ERNTupleSerializationMode {
0050    kForceNativeMode,
0051    kForceStreamerMode,
0052    kUnset
0053 };
0054
0055 ERNTupleSerializationMode GetRNTupleSerializationMode(TClass *cl);
0056
0057 /// Used in RFieldBase::Create() in order to get the comma-separated list of template types
0058 /// E.g., gets {"int", "std::variant<double,int>"} from "int,std::variant<double,int>".
0059 /// If maxArgs > 0, stop tokenizing after the given number of tokens are found. Used to strip
0060 /// STL allocator and other optional arguments.
0061 /// TODO(jblomer): Try to merge with TClassEdit::TSplitType
0062 std::vector<std::string> TokenizeTypeList(std::string_view templateType, std::size_t maxArgs = 0);
0063
0064 /// Helper to check if a given actualTypeName matches the expectedTypeName, either from RField<T>::TypeName() or
0065 /// GetRenormalizedTypeName(). Usually, this check can be done with a simple string comparison. The failure case,
0066 /// however, needs to additionally check for ROOT-specific special cases.
0067 bool IsMatchingFieldType(std::string_view actualTypeName, std::string_view expectedTypeName, const std::type_info &ti);
0068
0069 /// Prints the hierarchy of types with their field names and field IDs for the given in-memory field and the
0070 /// on-disk hierarchy, matching the fields on-disk ID with the information of the descriptor.
0071 /// Useful information when the in-memory field cannot be matched to the the on-disk information.
0072 std::string GetTypeTraceReport(const RFieldBase &field, const RNTupleDescriptor &desc);
0073
0074 } // namespace Internal
0075 } // namespace ROOT
0076
0077 #endif