Class: Tempfile

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

Overview

A class for managing temporary files. This library is written to be thread safe.

Constant Summary collapse

MAX_TRY = 
10
@@cleanlist = 
[]

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(basename, tmpdir = Dir::tmpdir) ⇒ Tempfile

Creates a temporary file of mode 0600 in the temporary directory whose name is basename.pid.n and opens with mode "w+". A Tempfile object works just like a File object.

If tmpdir is omitted, the temporary directory is determined by Dir::tmpdir provided by 'tmpdir.rb'. When $SAFE > 0 and the given tmpdir is tainted, it uses /tmp. (Note that ENV values are tainted by default)



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

def initialize(basename, tmpdir=Dir::tmpdir)
  if $SAFE > 0 and tmpdir.tainted?
    tmpdir = '/tmp'
  end

  lock = nil
  n = failure = 0
  
  begin
    Thread.critical = true

    begin
	tmpname = File.join(tmpdir, make_tmpname(basename, n))
	lock = tmpname + '.lock'
	n += 1
    end while @@cleanlist.include?(tmpname) or
	File.exist?(lock) or File.exist?(tmpname)

    Dir.mkdir(lock)
  rescue
    failure += 1
    retry if failure < MAX_TRY
    raise "cannot generate tempfile `%s'" % tmpname
  ensure
    Thread.critical = false
  end

  @data = [tmpname]
  @clean_proc = Tempfile.callback(@data)
  ObjectSpace.define_finalizer(self, @clean_proc)

  @tmpfile = File.open(tmpname, File::RDWR|File::CREAT|File::EXCL, 0600)
  @tmpname = tmpname
  @@cleanlist << @tmpname
  @data[1] = @tmpfile
  @data[2] = @@cleanlist

  super(@tmpfile)

  # Now we have all the File/IO methods defined, you must not
  # carelessly put bare puts(), etc. after this.

  Dir.rmdir(lock)
end

Class Method Details

.callback(data) ⇒ Object

:nodoc:



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# File 'lib/tempfile.rb', line 143

def callback(data)	# :nodoc:
  pid = $$
  lambda{
	if pid == $$ 
	  path, tmpfile, cleanlist = *data

	  print "removing ", path, "..." if $DEBUG

	  tmpfile.close if tmpfile

	  # keep this order for thread safeness
	  File.unlink(path) if File.exist?(path)
	  cleanlist.delete(path) if cleanlist

	  print "done\n" if $DEBUG
	end
  }
end

.open(*args) ⇒ Object

If no block is given, this is a synonym for new().

If a block is given, it will be passed tempfile as an argument, and the tempfile will automatically be closed when the block terminates. In this case, open() returns nil.



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# File 'lib/tempfile.rb', line 167

def open(*args)
  tempfile = new(*args)

  if block_given?
	begin
	  yield(tempfile)
	ensure
	  tempfile.close
	end

	nil
  else
	tempfile
  end
end

Instance Method Details

#close(unlink_now = false) ⇒ Object

Closes the file. If the optional flag is true, unlinks the file after closing.

If you don't explicitly unlink the temporary file, the removal will be delayed until the object is finalized.



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# File 'lib/tempfile.rb', line 93

def close(unlink_now=false)
  if unlink_now
    close!
  else
    _close
  end
end

#close! ⇒ Object

Closes and unlinks the file.



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# File 'lib/tempfile.rb', line 102

def close!
  _close
  @clean_proc.call
  ObjectSpace.undefine_finalizer(self)
end

#open ⇒ Object

Opens or reopens the file with mode "r+".



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# File 'lib/tempfile.rb', line 75

def open
  @tmpfile.close if @tmpfile
  @tmpfile = File.open(@tmpname, 'r+')
  @data[1] = @tmpfile
  __setobj__(@tmpfile)
end

#path ⇒ Object

Returns the full path name of the temporary file.



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# File 'lib/tempfile.rb', line 126

def path
  @tmpname
end

#size ⇒ Object Also known as: length

Returns the size of the temporary file. As a side effect, the IO buffer is flushed before determining the size.



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# File 'lib/tempfile.rb', line 132

def size
  if @tmpfile
    @tmpfile.flush
    @tmpfile.stat.size
  else
    0
  end
end

#unlink ⇒ Object Also known as: delete

Unlinks the file. On UNIX-like systems, it is often a good idea to unlink a temporary file immediately after creating and opening it, because it leaves other programs zero chance to access the file.



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# File 'lib/tempfile.rb', line 112

def unlink
  # keep this order for thread safeness
  begin
    File.unlink(@tmpname) if File.exist?(@tmpname)
    @@cleanlist.delete(@tmpname)
    @data = @tmpname = nil
    ObjectSpace.undefine_finalizer(self)
  rescue Errno::EACCES
    # may not be able to unlink on Windows; just ignore
  end
end