Module: Canopus::Workspace::FilePreviewable

Defined in:
lib/canopus/workspace/file_previewable.rb

Instance Method Summary collapse

Instance Method Details

#file_preview(path) ⇒ Object

A preview never creates a tab, loads a complete file, or changes selections.



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# File 'lib/canopus/workspace/file_previewable.rb', line 6

def file_preview(path)
  absolute = canonical_path(path)
  buffer = @buffers[absolute]
  stamp = buffer ? buffer.version : [File.mtime(absolute), File.size(absolute)]
  key = [absolute, stamp]
  @file_previews ||= {}
  return @file_previews[key] if @file_previews.key?(key)
  source = if buffer
    ending = [16_384, buffer.rope.bytesize].min
    begin
      buffer.rope.byteslice(0, ending).to_s
    rescue RangeError
      ending -= 1
      retry
    end
  else
    File.binread(absolute, 16_384).force_encoding(Encoding::UTF_8).scrub
  end
  rows = source.include?("\0") ? ["Binary / UTF-16 preview unavailable"] : source.lines.first(40).map { |line| line.chomp[0, 300] }
  @file_previews.shift if @file_previews.length >= 16
  @file_previews[key] = rows.freeze
rescue SystemCallError, Error => error
  ["Preview unavailable: #{error.message}"]
end