Class: Pry::Pager::SystemPager

Inherits:
NullPager show all
Defined in:
lib/pry/pager.rb

Overview

‘SystemPager` buffers output until we’re pretty sure it’s at least a page long, then invokes an external pager and starts streaming output to it. If ‘#close` is called before then, it just prints out the buffered content.

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from NullPager

#print, #puts

Constructor Details

#initialize ⇒ SystemPager

Returns a new instance of SystemPager.



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# File 'lib/pry/pager.rb', line 161

def initialize(*)
  super
  @tracker = PageTracker.new(height, width)
  @buffer  = ""
  @pager   = nil
end

Class Method Details

.available? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pry/pager.rb', line 142

def self.available?
  if @system_pager.nil?
    @system_pager =
      begin
        pager_executable = default_pager.split(' ').first
        if Helpers::Platform.windows? || Helpers::Platform.windows_ansi?
          `where /Q #{pager_executable}`
        else
          `which #{pager_executable}`
        end
        $CHILD_STATUS.success?
      rescue StandardError
        false
      end
  else
    @system_pager
  end
end

.default_pager ⇒ Object 



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# File 'lib/pry/pager.rb', line 130

def self.default_pager
  pager = Pry::Env['PAGER'] || ''

  # Default to less, and make sure less is being passed the correct
  # options
  pager = "less -R -F -X" if pager.strip.empty? || pager =~ /^less\b/

  pager
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/pry/pager.rb', line 181

def close
  if invoked_pager?
    pager.close
  else
    @out.puts @buffer
  end
end

#write(str) ⇒ Object 



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# File 'lib/pry/pager.rb', line 168

def write(str)
  if invoked_pager?
    write_to_pager str
  else
    @tracker.record str
    @buffer += str

    write_to_pager @buffer if @tracker.page?
  end
rescue Errno::EPIPE
  raise StopPaging
end