Class: LogSlice

Inherits:
Object
  • Object
show all
Defined in:
lib/log_slice.rb,
lib/log_slice/search_boundary.rb

Defined Under Namespace

Classes: SearchBoundary

Constant Summary collapse

NEWLINE = 
"\n"
NEWLINE_CHAR = 
"\n"[0]

Instance Method Summary collapse

Constructor Details

#initialize(log_file, options = {}) ⇒ LogSlice

Returns a new instance of LogSlice.

Parameters:

  • log_file (File, String)
  • options (Hash) (defaults to: {}) —

    :exact_match default false



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# File 'lib/log_slice.rb', line 10

def initialize log_file, options={}
  @file = log_file.respond_to?(:seek) ? log_file : File.open(log_file, 'r')
  @exact_match = options[:exact_match] || false
  @search_boundary = SearchBoundary.new(@file.stat.size)
  @line_cursor = nil
end

Instance Method Details

#find(&compare) ⇒ File?

Find line in the file using the comparison function. Depends on lines being sorted. The comparison function will be passed lines from the file. It must return -1 if the line is later than the one it’s looking for, 1 if the line is earlier than the one it’s looking for, and 0 if it is the line it’s looking for.

Parameters:

  • compare (Proc) —

    comparison function

Returns:

  • (File, nil) —

    file after seeking to start of line or nil if line not found



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# File 'lib/log_slice.rb', line 25

def find &compare
  reset_progress_check
  @search_boundary.reset
  line = find_next_newline
  while making_progress?
    comp_value = compare.call(line)
    if comp_value == 0 # found matching line
      backtrack_to_first_line_match compare
      return @file
    else
      @search_boundary.send(comp_value < 0 ? :cursor_back : :cursor_forward)
      line = find_next_newline
    end
  end
  if @exact_match
    nil
  else
    backtrack_to_gap compare
    return @file.eof? ? nil : @file
  end
end