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Class: Prism::Source

Relationships & Source Files
Extension / Inclusion / Inheritance Descendants
Subclasses:
ASCIISource
Inherits: Object
Defined in: lib/prism/parse_result.rb,
prism/extension.c

Overview

This represents a source of Ruby code that has been parsed. It is used in conjunction with locations to allow them to resolve line numbers and source ranges.

Class Method Summary

Instance Attribute Summary

  • #offsets readonly

    The list of newline byte offsets in the source code.

  • #source readonly

    The source code that this source object represents.

  • #start_line readonly

    The line number where this source starts.

Instance Method Summary

Constructor Details

.new(source, start_line = 1, offsets = []) ⇒ Source

Create a new source object with the given source code.

[ GitHub ] 

  


# File 'lib/prism/parse_result.rb', line 45



def initialize(source, start_line = 1, offsets = [])
  @source = source
  @start_line = start_line # set after parsing is done
  @offsets = offsets # set after parsing is done
end


  







Class Method Details



  

    .for(source, start_line = 1, offsets = [])  
  



  

    

Create a new source object with the given source code. This method should be used instead of .new and it will return either a Source or a specialized and more performant ASCIISource if no multibyte characters are present in the source code.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 12



def self.for(source, start_line = 1, offsets = [])
  if source.ascii_only?
    ASCIISource.new(source, start_line, offsets)
  elsif source.encoding == Encoding::BINARY
    source.force_encoding(Encoding::UTF_8)

    if source.valid_encoding?
      new(source, start_line, offsets)
    else
      # This is an extremely niche use case where the file is marked as
      # binary, contains multi-byte characters, and those characters are not
      # valid UTF-8. In this case we'll mark it as binary and fall back to
      # treating everything as a single-byte character. This _may_ cause
      # problems when asking for code units, but it appears to be the
      # cleanest solution at the moment.
      source.force_encoding(Encoding::BINARY)
      ASCIISource.new(source, start_line, offsets)
    end
  else
    new(source, start_line, offsets)
  end
end


  







Instance Attribute Details



  

    #offsets   (readonly)
  



  

    

The list of newline byte offsets in the source code.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 42



attr_reader :offsets


  








  

    #source   (readonly)
  



  

    

The source code that this source object represents.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 36



attr_reader :source


  








  

    #start_line   (readonly)
  



  

    

The line number where this source starts.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 39



attr_reader :start_line


  







Instance Method Details



  

    #character_column(byte_offset)  
  



  

    

Return the column number in characters for the given byte offset.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 107



def character_column(byte_offset)
  character_offset(byte_offset) - character_offset(line_start(byte_offset))
end


  








  

    #character_offset(byte_offset)  
  



  

    

Return the character offset for the given byte offset.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 102



def character_offset(byte_offset)
  (source.byteslice(0, byte_offset) or raise).length
end


  








  

    #code_units_cache(encoding)  
  



  

    

Generate a cache that targets a specific encoding for calculating code unit offsets.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 135



def code_units_cache(encoding)
  CodeUnitsCache.new(source, encoding)
end


  








  

    #code_units_column(byte_offset, encoding)  
  



  

    

Returns the column number in code units for the given encoding for the given byte offset.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 141



def code_units_column(byte_offset, encoding)
  code_units_offset(byte_offset, encoding) - code_units_offset(line_start(byte_offset), encoding)
end


  








  

    #code_units_offset(byte_offset, encoding)  
  



  

    

Returns the offset from the start of the file for the given byte offset counting in code units for the given encoding.



This method is tested with UTF-8, UTF-16, and UTF-32. If there is the concept of code units that differs from the number of characters in other encodings, it is not captured here.



We purposefully replace invalid and undefined characters with replacement characters in this conversion. This happens for two reasons. First, it’s possible that the given byte offset will not occur on a character boundary. Second, it’s possible that the source code will contain a character that has no equivalent in the given encoding.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 123



def code_units_offset(byte_offset, encoding)
  byteslice = (source.byteslice(0, byte_offset) or raise).encode(encoding, invalid: :replace, undef: :replace)

  if encoding == Encoding::UTF_16LE || encoding == Encoding::UTF_16BE
    byteslice.bytesize / 2
  else
    byteslice.length
  end
end


  








  

    #column(byte_offset)  
  



  

    

Return the column number for the given byte offset.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 97



def column(byte_offset)
  byte_offset - line_start(byte_offset)
end


  








  

    #deep_freeze  
  



  

    

Freeze this object and the objects it contains.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 146



def deep_freeze
  source.freeze
  offsets.freeze
  freeze
end


  








  

    #encoding  
  



  

    

Returns the encoding of the source code, which is set by parameters to the parser or by the encoding magic comment.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 63



def encoding
  source.encoding
end


  








  

    #find_line(byte_offset)   (private)
  



  

    

Binary search through the offsets to find the line number for the given byte offset.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 156



def find_line(byte_offset)
  left = 0
  right = offsets.length - 1

  while left <= right
    mid = left + (right - left) / 2
    return mid if (offset = offsets[mid]) == byte_offset

    if offset < byte_offset
      left = mid + 1
    else
      right = mid - 1
    end
  end

  left - 1
end


  








  

    #line(byte_offset)  
  



  

    

Binary search through the offsets to find the line number for the given byte offset.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 80



def line(byte_offset)
  start_line + find_line(byte_offset)
end


  








  

    #line_end(byte_offset)  
  



  

    

Returns the byte offset of the end of the line corresponding to the given byte offset.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 92



def line_end(byte_offset)
  offsets[find_line(byte_offset) + 1] || source.bytesize
end


  








  

    #line_start(byte_offset)  
  



  

    

Return the byte offset of the start of the line corresponding to the given byte offset.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 86



def line_start(byte_offset)
  offsets[find_line(byte_offset)]
end


  








  

    #lines  
  



  

    

Returns the lines of the source code as an array of strings.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 68



def lines
  source.lines
end


  








  

    #replace_offsets(offsets)  
  



  

    

Replace the value of offsets with the given value.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 57



def replace_offsets(offsets)
  @offsets.replace(offsets)
end


  








  

    #replace_start_line(start_line)  
  



  

    

Replace the value of start_line with the given value.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 52



def replace_start_line(start_line)
  @start_line = start_line
end


  








  

    #slice(byte_offset, length)  
  



  

    

Perform a byteslice on the source code using the given byte offset and byte length.


  



  [ GitHub ]


  

  


# File 'lib/prism/parse_result.rb', line 74



def slice(byte_offset, length)
  source.byteslice(byte_offset, length) or raise
end