Class: Linguist::Shebang

Inherits:
Object
  • Object
show all
Defined in:
lib/linguist/shebang.rb

Class Method Summary collapse

Class Method Details

.call(blob, _ = nil) ⇒ Object

Public: Use shebang to detect language of the blob.

blob - An object that quacks like a blob.

Examples

Shebang.call(FileBlob.new("path/to/file"))

Returns an Array with one Language if the blob has a shebang with a valid interpreter, or empty if there is no shebang.



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# File 'lib/linguist/shebang.rb', line 13

def self.call(blob, _ = nil)
  Language.find_by_interpreter interpreter(blob.data)
end

.interpreter(data) ⇒ Object

Public: Get the interpreter from the shebang

Returns a String or nil



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# File 'lib/linguist/shebang.rb', line 20

def self.interpreter(data)
  shebang = data.lines.first

  # First line must start with #!
  return unless shebang && shebang.start_with?("#!")

  s = StringScanner.new(shebang)

  # There was nothing after the #!
  return unless path = s.scan(/^#!\s*\S+/)

  # Keep going
  script = path.split('/').last

  # if /usr/bin/env type shebang then walk the string
  if script == 'env'
    s.scan(/\s+/)
    s.scan(/.*=[^\s]+\s+/) # skip over variable arguments e.g. foo=bar
    script = s.scan(/\S+/)
  end

  # Interpreter was /usr/bin/env with no arguments
  return unless script

  # "python2.6" -> "python2"
  script.sub!(/(\.\d+)$/, '')

  # #! perl -> perl
  script.sub!(/^#!\s*/, '')

  # Check for multiline shebang hacks that call `exec`
  if script == 'sh' &&
    data.lines.first(5).any? { |l| l.match(/exec (\w+).+\$0.+\$@/) }
    script = $1
  end

  File.basename(script)
end