Module: Optimize::Codec::IseqEnvelope

Defined in:
lib/optimize/codec/iseq_envelope.rb

Overview

Encodes and decodes the per-iseq envelope (body record + data sections).

Binary layout (from research/cruby/ibf-format.md §4):

Each iseq is serialized by ibf_dump_iseq_each:
  1. Data sections written first (bytecode, param opt table, keyword params,
     insns_info body, insns_info positions, local table, lvar states, catch table,
     ci entries, outer variables)
  2. Body record written last — a sequential stream of small_values (41 fields)

The iseq offset array (at header.iseq_list_offset) contains absolute offsets
pointing to each body record (NOT the start of data sections).

Relative offsets in the body record are stored as (body_offset - actual_offset),
i.e. a backward distance. Loading: actual_offset = body_offset - stored_value.

Strategy for byte-identical round-trip:

- Read the body record fields (41 small_values) to extract metadata.
- Store raw body record bytes in misc[:raw_body] for verbatim re-emission.
- Derive data section spans from body-record relative offsets and store each
  data section's raw bytes in misc for verbatim re-emission.
- Decode high-value metadata fields (name, path, type, arg_spec, etc.) for IR use.
- On encode: re-emit data sections verbatim, then re-emit raw body bytes.

Constant Summary collapse

ISEQ_TYPES =

ISEQ_TYPE_* enum values from Ruby (iseq.h / compile.c).

{
  0  => :top,
  1  => :method,
  2  => :block,
  3  => :class,
  4  => :rescue,
  5  => :ensure,
  6  => :eval,
  7  => :main,
  8  => :plain,
  9  => :defined_guard,
}.freeze
ISEQ_TYPE_NAMES = 
ISEQ_TYPES.invert.freeze

Class Method Summary collapse

Class Method Details

.decode(binary, body_offset, header, object_table, all_functions) ⇒ IR::Function

Decode one iseq envelope from binary (the full YARB binary string).

Parameters:

  • binary (String) —

    full YARB binary (ASCII-8BIT)

  • body_offset (Integer) —

    absolute byte offset of the body record

  • header (Header) —

    decoded header (for wordsize etc.)

  • object_table (ObjectTable) —

    decoded object table (for label resolution)

  • all_functions (Array<IR::Function|nil>) —

    iseq-list indexed array being built

Returns:



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# File 'lib/optimize/codec/iseq_envelope.rb', line 65

def self.decode(binary, body_offset, header, object_table, all_functions)
  reader = BinaryReader.new(binary)
  reader.seek(body_offset)

  body_start = body_offset

  # Read all 41 body record small_value fields in order.
  type_val                          = reader.read_small_value
  iseq_size                         = reader.read_small_value
  bytecode_offset_rel               = reader.read_small_value
  bytecode_size                     = reader.read_small_value
  param_flags                       = reader.read_small_value
  param_size                        = reader.read_small_value
  param_lead_num                    = reader.read_small_value
  param_opt_num                     = reader.read_small_value
  param_rest_start                  = reader.read_small_value
  param_post_start                  = reader.read_small_value
  param_post_num                    = reader.read_small_value
  param_block_start                 = reader.read_small_value
  param_opt_table_offset_rel        = reader.read_small_value
  param_keyword_offset              = reader.read_small_value
  location_pathobj_index            = reader.read_small_value
  location_base_label_index         = reader.read_small_value
  location_label_index              = reader.read_small_value
  location_first_lineno             = reader.read_small_value
  location_node_id                  = reader.read_small_value
  location_beg_lineno               = reader.read_small_value
  location_beg_column               = reader.read_small_value
  location_end_lineno               = reader.read_small_value
  location_end_column               = reader.read_small_value
  insns_info_body_offset_rel        = reader.read_small_value
  insns_info_positions_offset_rel   = reader.read_small_value
  insns_info_size                   = reader.read_small_value
  local_table_offset_rel            = reader.read_small_value
  lvar_states_offset_rel            = reader.read_small_value
  catch_table_size                  = reader.read_small_value
  catch_table_offset_rel           = reader.read_small_value
  parent_iseq_index                 = reader.read_small_value
  local_iseq_index                  = reader.read_small_value
  mandatory_only_iseq_index         = reader.read_small_value
  ci_entries_offset_rel             = reader.read_small_value
  outer_variables_offset_rel        = reader.read_small_value
  variable_flip_count               = reader.read_small_value
  local_table_size                  = reader.read_small_value
  ivc_size                          = reader.read_small_value
  icvarc_size                       = reader.read_small_value
  ise_size                          = reader.read_small_value
  ic_size                           = reader.read_small_value
  ci_size                           = reader.read_small_value
  stack_max                         = reader.read_small_value
  builtin_attrs                     = reader.read_small_value
  prism                             = reader.read_small_value

  body_end = reader.pos

  # Capture raw body bytes for verbatim re-emission.
  raw_body = binary.byteslice(body_start, body_end - body_start)

  # Resolve relative offsets → absolute offsets.
  # Formula: actual_offset = body_offset - stored_relative_value
  # A stored value of 0 means "not present" for optional sections.
  bytecode_abs     = bytecode_offset_rel > 0 ? body_offset - bytecode_offset_rel : nil
  opt_table_abs    = param_opt_table_offset_rel > 0 ? body_offset - param_opt_table_offset_rel : nil
  kw_abs           = param_keyword_offset > 0 ? param_keyword_offset : nil  # absolute, not relative
  insns_body_abs   = insns_info_body_offset_rel > 0 ? body_offset - insns_info_body_offset_rel : nil
  insns_pos_abs    = insns_info_positions_offset_rel > 0 ? body_offset - insns_info_positions_offset_rel : nil
  local_table_abs  = local_table_offset_rel > 0 ? body_offset - local_table_offset_rel : nil
  lvar_states_abs  = lvar_states_offset_rel > 0 ? body_offset - lvar_states_offset_rel : nil
  catch_table_abs  = catch_table_offset_rel > 0 ? body_offset - catch_table_offset_rel : nil
  ci_entries_abs   = ci_entries_offset_rel > 0 ? body_offset - ci_entries_offset_rel : nil
  outer_vars_abs   = outer_variables_offset_rel > 0 ? body_offset - outer_variables_offset_rel : nil

  # Resolve names from object table.
  objects = object_table.objects
  label     = objects[location_label_index]
  base_label = objects[location_base_label_index]
  pathobj    = objects[location_pathobj_index]

  # pathobj is either a String (path only) or an Array [path, realpath] (indices).
  path_str = abs_path_str = nil
  if pathobj.is_a?(Array)
    # Array stores object-table indices; resolve them.
    path_str     = objects[pathobj[0]]
    abs_path_str = objects[pathobj[1]]
  elsif pathobj.is_a?(String)
    path_str = pathobj
  end

  # Decode type symbol.
  type_sym = ISEQ_TYPES[type_val] || type_val

  # Decode param flags.
  arg_spec = {
    flags:         param_flags,
    size:          param_size,
    lead_num:      param_lead_num,
    opt_num:       param_opt_num,
    rest_start:    param_rest_start,
    post_start:    param_post_start,
    post_num:      param_post_num,
    block_start:   param_block_start,
    has_lead:      param_flags[0] == 1,
    has_opt:       param_flags[1] == 1,
    has_rest:      param_flags[2] == 1,
    has_post:      param_flags[3] == 1,
    has_kw:        param_flags[4] == 1,
    has_kwrest:    param_flags[5] == 1,
    has_block:     param_flags[6] == 1,
  }

  # Store all raw body fields in misc for faithful round-trip.
  misc = {
    raw_body:                       raw_body,
    type_val:                       type_val,
    iseq_size:                      iseq_size,
    bytecode_offset_rel:            bytecode_offset_rel,
    bytecode_size:                  bytecode_size,
    param_flags:                    param_flags,
    param_size:                     param_size,
    param_lead_num:                 param_lead_num,
    param_opt_num:                  param_opt_num,
    param_rest_start:               param_rest_start,
    param_post_start:               param_post_start,
    param_post_num:                 param_post_num,
    param_block_start:              param_block_start,
    param_opt_table_offset_rel:     param_opt_table_offset_rel,
    param_keyword_offset:           param_keyword_offset,
    location_pathobj_index:         location_pathobj_index,
    location_base_label_index:      location_base_label_index,
    location_label_index:           location_label_index,
    location_first_lineno:          location_first_lineno,
    location_node_id:               location_node_id,
    location_beg_lineno:            location_beg_lineno,
    location_beg_column:            location_beg_column,
    location_end_lineno:            location_end_lineno,
    location_end_column:            location_end_column,
    insns_info_body_offset_rel:     insns_info_body_offset_rel,
    insns_info_positions_offset_rel: insns_info_positions_offset_rel,
    insns_info_size:                insns_info_size,
    local_table_offset_rel:         local_table_offset_rel,
    lvar_states_offset_rel:         lvar_states_offset_rel,
    catch_table_size:               catch_table_size,
    catch_table_offset_rel:         catch_table_offset_rel,
    parent_iseq_index:              parent_iseq_index,
    local_iseq_index:               local_iseq_index,
    mandatory_only_iseq_index:      mandatory_only_iseq_index,
    ci_entries_offset_rel:          ci_entries_offset_rel,
    outer_variables_offset_rel:     outer_variables_offset_rel,
    variable_flip_count:            variable_flip_count,
    local_table_size:               local_table_size,
    ivc_size:                       ivc_size,
    icvarc_size:                    icvarc_size,
    ise_size:                       ise_size,
    ic_size:                        ic_size,
    ci_size:                        ci_size,
    stack_max:                      stack_max,
    builtin_attrs:                  builtin_attrs,
    prism:                          prism,
    # Absolute offsets (for layout tracking)
    bytecode_abs:                   bytecode_abs,
    opt_table_abs:                  opt_table_abs,
    kw_abs:                         kw_abs,
    insns_body_abs:                 insns_body_abs,
    insns_pos_abs:                  insns_pos_abs,
    local_table_abs:               local_table_abs,
    lvar_states_abs:                lvar_states_abs,
    catch_table_abs:                catch_table_abs,
    ci_entries_abs:                 ci_entries_abs,
    outer_vars_abs:                 outer_vars_abs,
  }

  # Decode the instruction stream from raw bytecode bytes into IR::Instruction array.
  # We keep raw operand indices (not resolved Ruby objects) so that re-encoding
  # produces byte-identical output.
  raw_bytecode = bytecode_abs && bytecode_size > 0 ?
                   binary.byteslice(bytecode_abs, bytecode_size) : "".b

  # Decode this iseq's own ci_entries blob into IR::CallData records so
  # the InstructionStream decoder can attach them to each send-family
  # instruction's CALLDATA operand slot. ci entries are per-iseq; we do
  # NOT pool them across iseqs.
  # Slice from ci_entries_abs up to body_offset (section end is at most
  # there; CiEntries.decode only consumes ci_size records so any trailing
  # bytes are ignored). iseq_list.rb re-captures a tighter raw slice for
  # round-trip via misc[:ci_entries_raw] after this returns.
  ci_entries_raw = ci_entries_abs && ci_size > 0 ?
                     binary.byteslice(ci_entries_abs, body_offset - ci_entries_abs) : "".b
  ci_entries_records = CiEntries.decode(ci_entries_raw, ci_size)

  instructions = InstructionStream.decode(
    raw_bytecode, object_table, all_functions,
    ci_entries: ci_entries_records,
  )
  # Store the raw bytecode in misc so IseqList can re-emit the region verbatim.
  misc[:raw_bytecode] = raw_bytecode

  # Decode the catch table into IR::CatchEntry objects.
  # The slot_map maps YARV slot index → IR::Instruction (by identity).
  catch_entries = nil
  if catch_table_size > 0 && catch_table_abs
    slot_to_inst = InstructionStream.slot_map(instructions)
    ct_reader = BinaryReader.new(binary)
    ct_reader.seek(catch_table_abs)
    catch_entries = CatchTable.decode(ct_reader, catch_table_size, slot_to_inst)
  end

  # Decode the insns_info (line info) table into IR::LineEntry objects.
  # CRuby splits this into two sections:
  #   - body section (insns_body_abs): N × (line_no, node_id, events) — absolute small_values
  #   - positions section (insns_pos_abs): N × pos_delta — delta-encoded slot positions
  line_entries = nil
  if insns_info_size > 0 && insns_body_abs && insns_pos_abs
    slot_to_inst     = InstructionStream.slot_map(instructions)
    inst_to_slot     = InstructionStream.inst_to_slot_map(instructions)
    slot_to_containing = InstructionStream.slot_to_containing_inst_map(instructions)
    body_reader = BinaryReader.new(binary)
    body_reader.seek(insns_body_abs)
    pos_reader = BinaryReader.new(binary)
    pos_reader.seek(insns_pos_abs)
    line_entries = LineInfo.decode(body_reader, pos_reader, insns_info_size, slot_to_inst, slot_to_containing, inst_to_slot)
  end

  # Decode the opt_table into IR::ArgPositions (instruction references).
  # Only present when param_opt_num > 0.
  arg_positions = nil
  if param_opt_num > 0 && opt_table_abs
    slot_to_inst = InstructionStream.slot_map(instructions)
    arg_positions = ArgPositions.decode(
      binary, opt_table_abs, param_opt_num, slot_to_inst
    )
  end

  # Build the IR::Function. children will be populated by the caller.
  IR::Function.new(
    name:          label.to_s,
    path:          path_str.to_s,
    absolute_path: abs_path_str,
    first_lineno:  location_first_lineno,
    type:          type_sym,
    arg_spec:      arg_spec,
    local_table:   nil,   # raw bytes stored in misc if needed
    catch_table:   nil,   # raw bytes stored in misc if needed
    line_info:     nil,   # raw bytes stored in misc if needed
    catch_entries: catch_entries,
    line_entries:  line_entries,
    arg_positions: arg_positions,
    instructions:  instructions,
    children:      [],
    misc:          misc,
  )
end

.encode(writer, function, data_region_offsets) ⇒ Integer

Encode one iseq’s body record into writer by re-emitting all 45 small_values from IR fields and data_region_offsets.

Relative offset fields are computed as: body_offset - abs_offset where body_offset = data_region_offsets. A stored value of 0 means the section is absent. param_keyword_offset is stored absolute (not relative).

Parameters:

  • writer (BinaryWriter)
  • function (IR::Function)
  • data_region_offsets (Hash) —

    absolute byte offsets keyed by symbol (:body_offset_abs, :bytecode_abs, :opt_table_abs, :kw_abs, :insns_body_abs,

    :insns_pos_abs, :local_table_abs, :lvar_states_abs, :catch_table_abs,
:ci_entries_abs, :outer_vars_abs)

Returns:

  • (Integer) —

    byte offset within the writer buffer where the body record starts



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# File 'lib/optimize/codec/iseq_envelope.rb', line 332

def self.encode(writer, function, data_region_offsets)
  misc = function.misc
  body_offset = data_region_offsets[:body_offset_abs]

  # Helper: compute rel offset (body_offset - abs), or 0 if absent.
  rel = ->(key) {
    abs = data_region_offsets[key]
    (abs && abs > 0) ? body_offset - abs : 0
  }

  # Derive type_val from IR type symbol if possible, else fall back to misc.
  type_val = ISEQ_TYPE_NAMES[function.type] || misc[:type_val]

  # location_first_lineno from IR (should equal misc value for unmodified IR).
  location_first_lineno = function.first_lineno

  buf_start = writer.pos

  # Emit all 45 small_values in the exact order the decoder reads them.
  writer.write_small_value(type_val)
  iseq_size = if function.instructions
                InstructionStream.total_slots(function.instructions)
              else
                misc[:iseq_size]
              end
  writer.write_small_value(iseq_size)
  writer.write_small_value(rel.call(:bytecode_abs))
  # Use fresh bytecode_size from data_region_offsets when available (length-changing edits).
  bytecode_size_val = data_region_offsets.key?(:bytecode_size) ? data_region_offsets[:bytecode_size] : misc[:bytecode_size]
  writer.write_small_value(bytecode_size_val)
  writer.write_small_value(misc[:param_flags])
  writer.write_small_value(misc[:param_size])
  writer.write_small_value(misc[:param_lead_num])
  writer.write_small_value(misc[:param_opt_num])
  writer.write_small_value(misc[:param_rest_start])
  writer.write_small_value(misc[:param_post_start])
  writer.write_small_value(misc[:param_post_num])
  writer.write_small_value(misc[:param_block_start])
  writer.write_small_value(rel.call(:opt_table_abs))
  # param_keyword_offset is absolute (not relative).
  writer.write_small_value(misc[:param_keyword_offset])
  writer.write_small_value(misc[:location_pathobj_index])
  writer.write_small_value(misc[:location_base_label_index])
  writer.write_small_value(misc[:location_label_index])
  writer.write_small_value(location_first_lineno)
  writer.write_small_value(misc[:location_node_id])
  writer.write_small_value(misc[:location_beg_lineno])
  writer.write_small_value(misc[:location_beg_column])
  writer.write_small_value(misc[:location_end_lineno])
  writer.write_small_value(misc[:location_end_column])
  writer.write_small_value(rel.call(:insns_body_abs))
  writer.write_small_value(rel.call(:insns_pos_abs))
  # Use caller-supplied filtered count when available (e.g. after instructions were deleted).
  insns_info_size = data_region_offsets.key?(:insns_info_size) ? data_region_offsets[:insns_info_size] : misc[:insns_info_size]
  writer.write_small_value(insns_info_size)
  writer.write_small_value(rel.call(:local_table_abs))
  writer.write_small_value(rel.call(:lvar_states_abs))
  # Use caller-supplied filtered count when available (e.g. after instructions were deleted).
  catch_table_size = data_region_offsets.key?(:catch_table_size) ? data_region_offsets[:catch_table_size] : misc[:catch_table_size]
  writer.write_small_value(catch_table_size)
  writer.write_small_value(rel.call(:catch_table_abs))
  writer.write_small_value(misc[:parent_iseq_index])
  writer.write_small_value(misc[:local_iseq_index])
  writer.write_small_value(misc[:mandatory_only_iseq_index])
  writer.write_small_value(rel.call(:ci_entries_abs))
  writer.write_small_value(rel.call(:outer_vars_abs))
  writer.write_small_value(misc[:variable_flip_count])
  writer.write_small_value(misc[:local_table_size])
  writer.write_small_value(misc[:ivc_size])
  writer.write_small_value(misc[:icvarc_size])
  writer.write_small_value(misc[:ise_size])
  writer.write_small_value(misc[:ic_size])
  # Use caller-supplied filtered count when available (e.g. after send
  # instructions were removed by a pass).
  ci_size_val = data_region_offsets.key?(:ci_size) ? data_region_offsets[:ci_size] : misc[:ci_size]
  writer.write_small_value(ci_size_val)
  # Use recomputed stack_max from IR when RECOMPUTE_STACK_MAX env var is set,
  # or always for functions without a stored misc value (e.g. synthesized IR).
  # For byte-identical round-trips, misc[:stack_max] takes precedence unless forced.
  stack_max_val = if ENV["RECOMPUTE_STACK_MAX"] || misc[:stack_max].nil?
    Codec::StackMax.compute(function)
  else
    misc[:stack_max]
  end
  writer.write_small_value(stack_max_val)
  writer.write_small_value(misc[:builtin_attrs])
  writer.write_small_value(misc[:prism])

  buf_start
end

.verify_offsets(function, data_region_offsets) ⇒ Object

Verify that the body-record relative offsets agree with data_region_offsets.

Re-reads the stored small_value fields from misc and resolves each relative offset back to an absolute byte position using the same formula the decoder uses (abs = body_offset - stored_rel). The original body_offset is derived from bytecode_offset_rel + data_region_offsets.

Raises RuntimeError if any resolved absolute offset does not match the corresponding entry in data_region_offsets.

Parameters:

  • function (IR::Function)
  • data_region_offsets (Hash) —

    absolute byte offsets keyed by symbol



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# File 'lib/optimize/codec/iseq_envelope.rb', line 435

def self.verify_offsets(function, data_region_offsets)
  misc = function.misc
  raw_body = misc[:raw_body]
  return unless raw_body && !raw_body.empty?

  # Re-read the 45 small_value fields from the raw body record.
  reader = BinaryReader.new(raw_body)

  _type_val                          = reader.read_small_value
  _iseq_size                         = reader.read_small_value
  bytecode_offset_rel                = reader.read_small_value
  _bytecode_size                     = reader.read_small_value
  _param_flags                       = reader.read_small_value
  _param_size                        = reader.read_small_value
  _param_lead_num                    = reader.read_small_value
  _param_opt_num                     = reader.read_small_value
  _param_rest_start                  = reader.read_small_value
  _param_post_start                  = reader.read_small_value
  _param_post_num                    = reader.read_small_value
  _param_block_start                 = reader.read_small_value
  param_opt_table_offset_rel         = reader.read_small_value
  param_keyword_offset               = reader.read_small_value
  _location_pathobj_index            = reader.read_small_value
  _location_base_label_index         = reader.read_small_value
  _location_label_index              = reader.read_small_value
  _location_first_lineno             = reader.read_small_value
  _location_node_id                  = reader.read_small_value
  _location_beg_lineno               = reader.read_small_value
  _location_beg_column               = reader.read_small_value
  _location_end_lineno               = reader.read_small_value
  _location_end_column               = reader.read_small_value
  insns_info_body_offset_rel         = reader.read_small_value
  insns_info_positions_offset_rel    = reader.read_small_value
  _insns_info_size                   = reader.read_small_value
  local_table_offset_rel             = reader.read_small_value
  lvar_states_offset_rel             = reader.read_small_value
  _catch_table_size                  = reader.read_small_value
  catch_table_offset_rel             = reader.read_small_value
  _parent_iseq_index                 = reader.read_small_value
  _local_iseq_index                  = reader.read_small_value
  _mandatory_only_iseq_index         = reader.read_small_value
  ci_entries_offset_rel              = reader.read_small_value
  outer_variables_offset_rel         = reader.read_small_value
  _variable_flip_count               = reader.read_small_value
  _local_table_size                  = reader.read_small_value
  _ivc_size                          = reader.read_small_value
  _icvarc_size                       = reader.read_small_value
  _ise_size                          = reader.read_small_value
  _ic_size                           = reader.read_small_value
  _ci_size                           = reader.read_small_value
  _stack_max                         = reader.read_small_value
  _builtin_attrs                     = reader.read_small_value
  _prism                             = reader.read_small_value

  # Derive original_body_offset from bytecode field (most reliably present).
  # Formula: body_offset - bytecode_offset_rel = bytecode_abs
  #       => body_offset = bytecode_abs + bytecode_offset_rel
  bytecode_abs_expected = data_region_offsets[:bytecode_abs]
  original_body_offset = nil
  if bytecode_offset_rel > 0 && bytecode_abs_expected && bytecode_abs_expected > 0
    original_body_offset = bytecode_abs_expected + bytecode_offset_rel
  end

  # If we cannot derive original_body_offset (no bytecode section), skip assertions.
  return unless original_body_offset

  # Fields with relative offsets (stored as body_offset - actual_offset).
  relative_fields = [
    [:bytecode_offset_rel,               bytecode_offset_rel,            :bytecode_abs],
    [:param_opt_table_offset_rel,         param_opt_table_offset_rel,     :opt_table_abs],
    [:insns_info_body_offset_rel,         insns_info_body_offset_rel,     :insns_body_abs],
    [:insns_info_positions_offset_rel,    insns_info_positions_offset_rel, :insns_pos_abs],
    [:local_table_offset_rel,             local_table_offset_rel,         :local_table_abs],
    [:lvar_states_offset_rel,             lvar_states_offset_rel,         :lvar_states_abs],
    [:catch_table_offset_rel,             catch_table_offset_rel,         :catch_table_abs],
    [:ci_entries_offset_rel,              ci_entries_offset_rel,          :ci_entries_abs],
    [:outer_variables_offset_rel,         outer_variables_offset_rel,     :outer_vars_abs],
  ]

  relative_fields.each do |name, stored_rel, key|
    next if stored_rel == 0
    expected_abs = data_region_offsets[key]
    next if expected_abs.nil? || expected_abs == 0

    resolved_abs = original_body_offset - stored_rel
    if resolved_abs != expected_abs
      raise RuntimeError,
        "body-record offset drift: field=#{name} stored_rel=#{stored_rel} " \
        "resolved_abs=#{resolved_abs} data_region_abs=#{expected_abs} " \
        "(iseq=#{function.name})"
    end
  end

  # param_keyword_offset is stored as an ABSOLUTE offset (not relative).
  kw_abs_expected = data_region_offsets[:kw_abs]
  if param_keyword_offset > 0 && kw_abs_expected && kw_abs_expected > 0
    if param_keyword_offset != kw_abs_expected
      raise RuntimeError,
        "body-record offset drift: field=param_keyword_offset stored_abs=#{param_keyword_offset} " \
        "data_region_abs=#{kw_abs_expected} (iseq=#{function.name})"
    end
  end
end