Class: Longleaf::FileSelector

Inherits:
Object
  • Object
show all
Includes:
Logging
Defined in:
lib/longleaf/candidates/file_selector.rb

Overview

Selects and allows for iteration over files which match a provided set of selection criteria

Direct Known Subclasses

RegisteredFileSelector

Constant Summary collapse

SPECIFICITY_PATH = 
'path'
SPECIFICITY_STORAGE_LOCATION = 
'storage_location'

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Logging

#initialize_logger, initialize_logger, #logger, logger

Constructor Details

#initialize(file_paths: nil, storage_locations: nil, app_config:) ⇒ FileSelector

May only provide either file_paths or storage_locations



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# File 'lib/longleaf/candidates/file_selector.rb', line 13

def initialize(file_paths: nil, storage_locations: nil, app_config:)
  if nil_or_empty?(file_paths) && nil_or_empty?(storage_locations)
    raise ArgumentError.new("Must provide either file paths or storage locations")
  end
  if !nil_or_empty?(file_paths) && !nil_or_empty?(storage_locations)
    raise ArgumentError.new("Cannot provide both file paths and storage locations")
  end
  @app_config = app_config
  # The top level paths targeted by this selector
  @target_paths = file_paths&.map do |path|
    # Resolve relative paths against pwd
    pathname = Pathname.new(path)
    if !pathname.absolute?
      path = File.join(Dir.pwd, path)
    end
    path = File.expand_path(path)

    # adding trailing /'s to directories
    if Dir.exist?(path) && !path.end_with?('/')
      path + '/'
    else
      path
    end
  end
  # The set of storage locations to select file paths from
  @storage_locations = storage_locations
  # Validate that the selected storage locations are known
  if @storage_locations.nil?
    @specificity = SPECIFICITY_PATH
  else
    @specificity = SPECIFICITY_STORAGE_LOCATION
    locations = @app_config.location_manager.locations
    @storage_locations.each do |loc_name|
      unless locations.key?(loc_name)
        raise StorageLocationUnavailableError.new("Cannot select unknown storage location #{loc_name}.")
      end
    end
  end
end

Instance Attribute Details

#specificity ⇒ Object (readonly)

Returns the value of attribute specificity



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# File 'lib/longleaf/candidates/file_selector.rb', line 10

def specificity
  @specificity
end

Instance Method Details

#each ⇒ Object

Iterate through the file paths for this selector and execute the provided block with each. A block is required.



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# File 'lib/longleaf/candidates/file_selector.rb', line 106

def each
  file_path = next_path
  until file_path.nil?
    yield file_path

    file_path = next_path
  end
end

#next_path ⇒ String

Get the next file path for this selector. or nil if no more files selected

Returns:

  • (String) —

    an absolute path to the next file targeted by this selector,



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# File 'lib/longleaf/candidates/file_selector.rb', line 69

def next_path
  if @paths.nil?
    # Start the paths listing out from the targetted set of paths for this selector
    # In reverse order since using a LIFO structure
    @paths = target_paths.reverse
  end

  # No more paths to return
  return nil if @paths&.empty?

  # Get the most recently added path for depth first traversal of selected paths
  path = @paths.pop
  until path.nil? do
    @app_config.location_manager.verify_path_in_location(path)

    if File.exist?(path)
      if File.directory?(path)
        logger.debug("Expanding directory #{path}")
        # For a directory, add all children to file_paths
        Dir.entries(path).sort.reverse_each do |child|
          @paths << File.join(path, child) unless child == '.' or child == '..'
        end
      else
        logger.debug("Returning file #{path}")
        return path
      end
    else
      raise InvalidStoragePathError.new("File #{path} does not exist.")
    end

    # Returned path was not a suitable file, try the next path
    path = @paths.pop
  end
end

#nil_or_empty?(value) ⇒ Boolean (private)

Returns:

  • (Boolean) 


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# File 'lib/longleaf/candidates/file_selector.rb', line 135

def nil_or_empty?(value)
  value.nil? || value.empty?
end

#storage_locations ⇒ Object

return [Array] a list of all storage locations being targeted by this selector



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# File 'lib/longleaf/candidates/file_selector.rb', line 116

def storage_locations
  # Determine what storage_locations are represented by the given file paths
  if @storage_locations.nil? && !@target_paths.nil?
    loc_set = Set.new
    @target_paths.each do |path|
      loc = @app_config.location_manager.get_location_by_path(path)
      loc_set.add(loc.name) unless loc.nil?
    end
    @storage_locations = loc_set.to_a
  end

  if @storage_locations.nil?
    @storage_locations = Array.new
  end

  @storage_locations
end

#target_paths ⇒ Array

Returns a list of top level paths from which files will be selected

Returns:

  • (Array) —

    a list of top level paths from which files will be selected



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# File 'lib/longleaf/candidates/file_selector.rb', line 54

def target_paths
  # If starting from locations, initialize by expanding locations out to their actual paths
  if @target_paths.nil? && !@storage_locations.nil?
    @target_paths = Array.new
    @storage_locations.each do |loc_name|
      @target_paths << @app_config.location_manager.locations[loc_name].path
    end
  end

  @target_paths
end