Module: PageMe

Includes:
POSIX::Spawn
Defined in:
lib/pageme.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#pager ⇒ Object 



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# File 'lib/pageme.rb', line 40

def pager
  @pager || ENV["PAGER"] || "less"
end

#paging_disabled=(value) ⇒ Object (writeonly)

Sets the attribute paging_disabled

Parameters:

  • value —

    the value to set the attribute paging_disabled to.



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# File 'lib/pageme.rb', line 24

def paging_disabled=(value)
  @paging_disabled = value
end

Class Method Details

.use_domain_socket_for_paging=(f) ⇒ Object 



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

def self.use_domain_socket_for_paging=(f)
  if f
    require "tempfile"
    require "socket"
  end
  @use_domain_socket_for_paging = f
end

.use_domain_socket_for_paging? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pageme.rb', line 18

def self.use_domain_socket_for_paging?
  @use_domain_socket_for_paging
end

Instance Method Details

#disable_paging ⇒ Object 



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# File 'lib/pageme.rb', line 32

def disable_paging
  self.paging_disabled = true
end

#enable_paging ⇒ Object 



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# File 'lib/pageme.rb', line 36

def enable_paging
  self.paging_disabled = false
end

#page(*args, &p) ⇒ Object 



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# File 'lib/pageme.rb', line 44

def page *args, &p
  args << p
  args.compact!

  if paging_disabled?
    page_to STDOUT, args
    return
  end

  t, w, server = nil

  if defined? JRUBY_VERSION
    loop do
      begin
        t = File.join(Dir::tmpdir, "socket-for-jruby-pager-#{rand(2**16)}")
        server = UNIXServer.new(t)
        break
      rescue Errno::EADDRINUSE
      end
    end


    child_pid = spawn "netcat -U #{t} | #{pager}"

    w = server.accept
  else
    r, w = IO.pipe
    child_pid = spawn pager, :in => r, w => :close
    r.close
  end

  previous_int_handler = Kernel.trap("SIGINT"){ Process.kill "INT", child_pid }
  previous_term_handler = Kernel.trap("SIGTERM") do 
    Process.kill "TERM", child_pid 
    Process.wait child_pid, Process::WUNTRACED 
    child_pid = nil
    if previous_term_handler == "DEFAULT"
      raise SignalException.new("SIGTERM")
    else
      previous_term_handler.call
    end
  end

  begin
    page_to w, args
  rescue Errno::EPIPE
  rescue Exception => e
    begin
      unless w.closed?
        w.puts "#{e.class}: #{e.message}"
        e.backtrace.each{|l| w.puts "\t#{l}" }
      end 
    rescue Errno::EPIPE
    end

    raise 
  ensure
    begin
      w.close unless w.closed?
    ensure
      Process.wait child_pid, Process::WUNTRACED  if child_pid
      Kernel.trap("SIGINT", previous_int_handler)
      Kernel.trap("SIGTERM", previous_term_handler)
      File.delete(t) if t
      server.close if server
    end
  end
  nil
end

#page_file(file) ⇒ Object

Raises:

  • (Errno::ENOENT) 


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# File 'lib/pageme.rb', line 114

def page_file file
  raise Errno::ENOENT, file unless File.exist? file

  system pager, file
  nil
end

#paging_disabled? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pageme.rb', line 26

def paging_disabled?
  return @paging_disabled if defined? paging_disabled

  !(STDOUT.tty?)
end

#with_paged_output ⇒ Object 



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# File 'lib/pageme.rb', line 121

def with_paged_output
  page do |o|
    original_stdout = STDOUT.dup
    original_stderr = STDERR.dup
    begin
      STDERR.reopen(o)
      STDOUT.reopen(o)
      yield
    ensure
      STDERR.reopen(original_stderr)
      STDOUT.reopen(original_stdout)
    end 
  end
end