Class: Cog::Helpers::FileScanner

Inherits:
Object
  • Object
show all
Defined in:
lib/cog/helpers/file_scanner.rb

Overview

Helper for scanning files for embed expansions

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(filename) ⇒ FileScanner

Returns a new instance of FileScanner.



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# File 'lib/cog/helpers/file_scanner.rb', line 18

def initialize(filename)
  @filename = filename
  @f = File.open filename, 'r'
  @f = @f.binmode if @f.respond_to?(:binmode)
  @lines = []
  @mark = nil
  @cap_begin_pos = nil
  @cap_end_pos = nil
  @cap_end_lineno = nil
  @match = nil # The last match object
  @win_fudge = if RUBY_PLATFORM =~ /(mswin|mingw)/
    x = @f.readline.end_with? "\r\n"
    @f.seek 0
    @f.lineno = 0
    x ? 0 : 1
  else
    0
  end
end

Instance Attribute Details

#marked_line_number ⇒ Fixnum (readonly)

Returns line number where mark! was called or -1 if mark! was not called.

Returns:

  • (Fixnum) —

    line number where mark! was called or -1 if mark! was not called



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# File 'lib/cog/helpers/file_scanner.rb', line 79

def marked_line_number
  @marked_line_number
end

#match ⇒ MatchData? (readonly)

Returns match data for the last matched pattern.

Returns:

  • (MatchData, nil) —

    match data for the last matched pattern



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# File 'lib/cog/helpers/file_scanner.rb', line 15

def match
  @match
end

Class Method Details

.scan(filename, pattern, opt = {}) {|scanner| ... } ⇒ Object?

Opens the given file for scanning.

Parameters:

  • filename (String) —

    path to the file which will be scanned

  • pattern (Regexp) —

    a pattern to test for

  • opt (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opt):

  • :occurrence (Fixnum) — default: 0 —

    0 for the first, 1 for the second, and so on

Yield Parameters:

Yield Returns:

  • (Object)

Returns:

  • (Object, nil) —

    the return value of the block, or nil if the pattern was not found



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# File 'lib/cog/helpers/file_scanner.rb', line 51

def self.scan(filename, pattern, opt={}, &block)
  s = new filename
  val = if s.read_until pattern, opt[:occurrence] || 0
    block.call s
  else
    nil
  end
  s.close
  val
end

Instance Method Details

#capture_until(pattern, opt = {}) ⇒ Boolean

Advances the file until the given pattern is encountered and captures lines as it reads. The line which matches the pattern will not be captured. Captured lines can later be recovered with captured_text

Parameters:

  • pattern (Regexp) —

    a pattern to test for

  • opt (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opt):

  • :but_not (Array<Regexp>, Regexp) — default: nil —

    if a line matching any of the provided patterns is found before the desired pattern :bad_pattern_found will be thrown

Returns:

  • (Boolean) —

    whether or not the pattern was found



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# File 'lib/cog/helpers/file_scanner.rb', line 113

def capture_until(pattern, opt={})
  @cap_begin_pos = @f.pos - win_fudge
  but_not = opt[:but_not] || []
  but_not = [but_not] unless but_not.is_a?(Array)
  while line = @f.readline
    but_not.each do |bad_pattern|
      if bad_pattern =~ line
        return false
      end
    end
    return true if line =~ pattern
    @lines << line
    @cap_end_pos = @f.pos # win_fudge not needed here
    @cap_end_lineno = @f.lineno
  end
rescue EOFError
  false
end

#captured_text ⇒ String

Returns text captured during capture_until. The last newline is stripped.

Returns:

  • (String) —

    text captured during capture_until. The last newline is stripped



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# File 'lib/cog/helpers/file_scanner.rb', line 133

def captured_text
  x = @lines.join('')
  x
end

#close ⇒ Object

Closes the scanned file, if it is not already closed



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# File 'lib/cog/helpers/file_scanner.rb', line 40

def close
  @f.close unless @f.closed?
end

#insert_at_mark(value) ⇒ Boolean

Returns whether or not the operation succeeded.

Parameters:

  • value (String) —

    value to be inserted into the file at the current position

Returns:

  • (Boolean) —

    whether or not the operation succeeded



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# File 'lib/cog/helpers/file_scanner.rb', line 159

def insert_at_mark(value)
  return false if @mark.nil?
  @f.seek 0
  @f.lineno = 0
  tmp.write @f.read(@mark)
  tmp.write value
  @f.readline # discard original
  tmp.write @f.read
  tmp.close
  close
  FileUtils.mv tmp_filename, @filename
  true
end

#mark! ⇒ nil

Remember this position. A later call to insert_at_mark will insert at this marked position

Returns:

  • (nil) 


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# File 'lib/cog/helpers/file_scanner.rb', line 68

def mark!
  @mark = @f.pos - win_fudge
  @marked_line_number = @f.lineno + 1
end

#read_until(pattern, n = 0) ⇒ Boolean

Advances the file until the (n+1)th occurence of the given pattern is encountered, or the end of the file is reached

Parameters:

  • pattern (Regexp) —

    a pattern to test for

  • n (Fixnum) (defaults to: 0) —

    0 for the first, 1 for the second, and so on

Returns:

  • (Boolean) —

    whether or not a match was found. Use #match to retrieve the match data



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# File 'lib/cog/helpers/file_scanner.rb', line 85

def read_until(pattern, n=0)
  i = 0
  mark!
  while (line = @f.readline) && i <= n
    if @match = pattern.match(line)
      return true if i == n
      i += 1
    end
    mark!
  end
rescue EOFError
  unmark!
  false
end

#readline_matches?(pattern) ⇒ Boolean

Advances the file by one line

Parameters:

  • pattern (Regexp) —

    a pattern to test for

Returns:

  • (Boolean) —

    whether or not the next line matched the pattern



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# File 'lib/cog/helpers/file_scanner.rb', line 103

def readline_matches?(pattern)
  !!(@f.readline =~ pattern)
rescue EOFError
  false
end

#replace_captured_text(value, opt = {}) ⇒ Boolean

Returns whether or not the operation succeeded.

Parameters:

  • value (String) —

    value to replace the captured_text with

  • opt (Boolean) (defaults to: {}) —

    :once (false) if once, the cog delimiters will be removed

Returns:

  • (Boolean) —

    whether or not the operation succeeded



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# File 'lib/cog/helpers/file_scanner.rb', line 141

def replace_captured_text(value, opt={})
  return false if @cap_begin_pos.nil? || @cap_end_pos.nil?
  @f.seek 0
  @f.lineno = 0
  tmp.write @f.read(opt[:once] ? @mark : @cap_begin_pos)
  tmp.write value
  @f.seek @cap_end_pos
  @f.lineno = @cap_end_lineno
  @f.readline if opt[:once]
  tmp.write @f.read
  tmp.close
  close
  FileUtils.mv tmp_filename, @filename
  true
end

#unmark! ⇒ Object 



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# File 'lib/cog/helpers/file_scanner.rb', line 73

def unmark!
  @mark = nil
  @marked_line_number = -1
end

#win_fudge ⇒ Object 



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# File 'lib/cog/helpers/file_scanner.rb', line 62

def win_fudge
  (@f.lineno - 1) * @win_fudge
end