Class: ContentBuffer

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

Overview

this class is used to track changes to an arbitrary buffer

Instance Method Summary collapse

Constructor Details

#initialize(initial_content) ⇒ ContentBuffer

Returns a new instance of ContentBuffer.



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# File 'lib/content_buffer.rb', line 6

def initialize(initial_content)
  @initial_content = initial_content
  @lines = @initial_content.split("\n")
end

Instance Method Details

#apply_transform!(transform) ⇒ Object 



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# File 'lib/content_buffer.rb', line 11

def apply_transform!(transform)
  start_row = transform[:start][:row]
  start_col = transform[:start][:col]
  finish_row = transform[:finish][:row] if transform[:finish]
  finish_col = transform[:finish][:col] if transform[:finish]
  text = transform[:text]

  if transform[:operation] == :delete
    # fix first line

    l = @lines[start_row]
    l = l[0...start_col]

    if (finish_row == start_row)
      l << @lines[start_row][finish_col..-1]
      @lines[start_row] = l
      return
    end

    @lines[start_row] = l

    # remove middle lines
    (finish_row - start_row).times { l = @lines.delete_at start_row + 1 }

    # fix last line
    @lines[start_row] << @lines[finish_row][finish_col - 1..-1]
  end

  if transform[:operation] == :insert
    @lines[start_row].insert(start_col, text)

    split = @lines[start_row].split("\n")

    if split.length > 1
      @lines[start_row] = split[0]
      i = 1
      split[1..-2].each do |line|
        @lines.insert(start_row + i, line)
        i += 1
      end
      @lines.insert(i, "") if @lines.length <= i
      @lines[i] = split[-1] + @lines[i]
    end
  end
end

#to_s ⇒ Object 



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# File 'lib/content_buffer.rb', line 57

def to_s
  @lines.join("\n")
end