Class SlotDescriptor

be/src/runtime/descriptors.h:123–339

class TupleDescriptor;

class SlotDescriptor {
 public:
  SlotId id() const { return id_; }
  const ColumnType& type() const { return type_; }
  const TupleDescriptor* parent() const { return parent_; }
  const TupleDescriptor* children_tuple_descriptor() const {
    return children_tuple_descriptor_;
  }
  /// Returns the column index of this slot, including partition keys.
  /// (e.g., col_pos - num_partition_keys = the table column this slot corresponds to)
  /// TODO: This function should eventually be replaced by col_path(). It is currently
  /// convenient for table formats for which we only support flat data.
  int col_pos() const { return col_path_[0]; }
  const SchemaPath& col_path() const { return col_path_; }

  /// Returns the field index in the generated llvm struct for this slot's tuple.
  /// The 'llvm_field_idx' is the index of the slot in the llvm codegen'd tuple struct.
  /// This takes into account any padding bytes.
  int llvm_field_idx() const { return slot_idx_; }

  int tuple_offset() const { return tuple_offset_; }
  const NullIndicatorOffset& null_indicator_offset() const {
    return null_indicator_offset_;
  }
  bool is_nullable() const { return null_indicator_offset_.bit_mask != 0; }
  int slot_size() const { return slot_size_; }

  TVirtualColumnType::type virtual_column_type() const { return virtual_column_type_; }
  bool IsVirtual() const { return virtual_column_type_ != TVirtualColumnType::NONE; }

  std::optional<int32_t> struct_field_idx() const { return struct_field_idx_; }

  /// Comparison function for ordering slot descriptors by their col_path_.
  /// Returns true if 'a' comes before 'b'.
  /// Orders the paths as in a depth-first traversal of the schema tree, as follows:
  /// - for each level i in min(a.path.size, b.path.size),
  ///   order the paths ascending by col_path_[i]
  /// - in case of ties, the path with smaller size comes first
  static bool ColPathLessThan(const SlotDescriptor* a, const SlotDescriptor* b);

  std::string DebugString() const;

  /// Return true if the physical layout of this descriptor matches the physical layout
  /// of other_desc, but not necessarily ids.
  bool LayoutEquals(const SlotDescriptor& other_desc) const;

  /// Load "any_val"'s value from 'raw_val_ptr', which must be a pointer to the matching
  /// native type, e.g. a StringValue or TimestampValue slot in a tuple.
  static void CodegenLoadAnyVal(CodegenAnyVal* any_val, llvm::Value* raw_val_ptr);

  /// Generate LLVM code at the insert position of 'builder' that returns a boolean value
  /// represented as a LLVM i1 indicating whether this slot is null in 'tuple'.
  llvm::Value* CodegenIsNull(
      LlvmCodeGen* codegen, LlvmBuilder* builder, llvm::Value* tuple) const;

  /// Generate LLVM code at the insert position of 'builder' that returns a boolean value
  /// represented as a LLVM i1 with value of the NULL bit at 'null_indicator_offset' in
  /// 'tuple'.