Class: CachedNestedFileReader

Inherits:
Object
  • Object
show all
Includes:
Exceptions
Defined in:
lib/cached_nested_file_reader.rb

Overview

The CachedNestedFileReader class provides functionality to read file lines with the ability to process ‘#import filename’ directives. When such a directive is encountered in a file, the corresponding ‘filename’ is read and its contents are inserted at that location. This class caches read files to avoid re-reading the same file multiple times. It allows clients to read lines with or without providing a block.

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Exceptions

error_handler

Constructor Details

#initialize(import_directive_line_pattern:, import_directive_parameter_scan:, import_parameter_variable_assignment:, shell:, shell_block_name:, symbol_command_substitution:, symbol_evaluated_expression:, symbol_force_quoted_literal:, symbol_raw_literal:, symbol_variable_reference:, hide_shebang: true) ⇒ CachedNestedFileReader

Returns a new instance of CachedNestedFileReader.



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# File 'lib/cached_nested_file_reader.rb', line 26

def initialize(
  import_directive_line_pattern:,
  import_directive_parameter_scan:,
  import_parameter_variable_assignment:,
  shell:,
  shell_block_name:,
  symbol_command_substitution:,
  symbol_evaluated_expression:,
  symbol_force_quoted_literal:,
  symbol_raw_literal:,
  symbol_variable_reference:,
  hide_shebang: true
)
  @file_cache = {}
  @import_directive_line_pattern = import_directive_line_pattern
  @import_directive_parameter_scan = import_directive_parameter_scan
  @import_parameter_variable_assignment = import_parameter_variable_assignment
  @shell = shell
  @shell_block_name = shell_block_name
  @symbol_command_substitution = symbol_command_substitution
  @symbol_evaluated_expression = symbol_evaluated_expression
  @symbol_force_quoted_literal = symbol_force_quoted_literal
  @symbol_raw_literal = symbol_raw_literal
  @symbol_variable_reference = symbol_variable_reference
  @hide_shebang = hide_shebang
end

Class Method Details

.warn_format(name, message, opts = {}) ⇒ Object 



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# File 'lib/cached_nested_file_reader.rb', line 61

def self.warn_format(name, message, opts = {})
  Exceptions.warn_format(
    "CachedNestedFileReader.#{name} -- #{message}",
    opts
  )
end

Instance Method Details

#error_handler(name = '', opts = {}) ⇒ Object 



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# File 'lib/cached_nested_file_reader.rb', line 53

def error_handler(name = '', opts = {})
  Exceptions.error_handler(
    "CachedNestedFileReader.#{name} -- #{$!}",
    caller.deref(6),
    opts
  )
end

#readlines(filename, depth = 0, context: '', import_paths: nil, indention: '', substitutions: {}, use_template_delimiters: false, clear_cache: true, read_cache: false, &block) ⇒ Object

yield each line to the block return the processed lines



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# File 'lib/cached_nested_file_reader.rb', line 70

def readlines(
  filename, depth = 0, context: '', import_paths: nil,
  indention: '', substitutions: {}, use_template_delimiters: false,
  clear_cache: true,
  read_cache: false,
  &block
)
  # clear cache if requested
  @file_cache.clear if clear_cache

  cache_key = build_cache_key(filename, substitutions)
  if @file_cache.key?(cache_key)
    return ["# dup #{cache_key}"] unless read_cache

    @file_cache[cache_key].each(&block) if block
    return @file_cache[cache_key]

    # do not return duplicates per filename and substitutions
    # return an indicator that the file was already read

  end
  raise Errno::ENOENT, filename unless filename

  directory_path = File.dirname(filename)
  processed_lines = []
  continued_line = nil # continued import directive
  File.readlines(filename, chomp: true).each.with_index do |segment, ind|
    wwt :readline, 'depth:', depth, 'filename:', filename, 'ind:', ind,
        'segment:', segment

    # [REQ:SHEBANG_HIDING] Filter shebang lines from processed output
    # [IMPL:SHEBANG_FILTERING] [ARCH:SHEBANG_EXTRACTION] [REQ:SHEBANG_HIDING]
    # first line is a shebang line if it starts with '#!'
    next if @hide_shebang && is_shebang_line?(segment, ind == 0)

    if continued_line || (Regexp.new(@import_directive_line_pattern) =~ segment)
      line = (continued_line || '') + segment
      # if segment ends in a continuation, prepend to next line
      if line.end_with?('\\')
        continued_line = line.chomp('\\')
        next
      end

      continued_line = nil

      # apply substitutions to the @import line
      line_sub1 = apply_line_substitutions(line, substitutions,
                                           use_template_delimiters)

      # parse the @import line
      Regexp.new(@import_directive_line_pattern) =~ line_sub1
      name_strip = $~[:name].strip
      params_string = $~[:params] || ''
      import_indention = indention + $~[:indention]
      # Parse parameters for text substitution
      import_substitutions, add_code = parse_import_params(params_string)

      if add_code
        # strings as NestedLines
        add_lines = add_code.map.with_index do |line2, ind2|
          nested_line = NestedLine.new(
            line2,
            depth + 1,
            import_indention,
            filename,
            ind2
          )
          block&.call(nested_line)

          nested_line
        end
        ww 'add_lines:', add_lines
        processed_lines += add_lines
      end
      merged_substitutions = substitutions.merge(import_substitutions)

      included_file_path =
        if name_strip =~ %r{^/}
          name_strip
        elsif import_paths
          find_files(name_strip,
                     import_paths + [directory_path])&.first
        else
          File.join(directory_path, name_strip)
        end

      raise Errno::ENOENT, name_strip unless included_file_path

      # Create a cache key for the imported file that includes both filename and parameters
      imported_cache_key = build_import_cache_key(included_file_path,
                                                  name_strip, params_string, merged_substitutions)

      # Check if we've already loaded this specific import
      if @file_cache.key?(imported_cache_key)
        imported_lines = @file_cache[imported_cache_key]
      else
        imported_lines = readlines(
          included_file_path, depth + 1,
          context: "#{filename}:#{ind + 1}",
          import_paths: import_paths,
          indention: import_indention,
          substitutions: merged_substitutions,
          use_template_delimiters: use_template_delimiters,
          clear_cache: false,
          &block
        )

        # Cache the imported lines with the specific import cache key
        @file_cache[imported_cache_key] = imported_lines
      end

      # Apply text substitutions to imported content
      processed_imported_lines = apply_substitutions(
        imported_lines,
        import_substitutions, use_template_delimiters
      )
      processed_lines += processed_imported_lines
    else
      # Apply substitutions to the current line
      substituted_line = apply_line_substitutions(segment, substitutions,
                                                  use_template_delimiters)
      nested_line = NestedLine.new(substituted_line, depth, indention,
                                   filename, ind)
      processed_lines.push(nested_line)
      block&.call(nested_line)
    end
  end

  wwt :read_document_code, 'processed_lines:', processed_lines
  @file_cache[cache_key] = processed_lines
rescue Errno::ENOENT => err
  CachedNestedFileReader.warn_format(
    'readlines', "#{err} @@ #{context}",
    { abort: true }
  )
rescue StandardError
  wwe $!
end