#
# tempfile - manipulates temporary files
#
# $Id: tempfile.rb 16127 2008-04-21 09:43:44Z knu $
#
require 'delegate'
require 'tmpdir'
# A class for managing temporary files. This library is written to be
# thread safe.
class Tempfile < DelegateClass(File)
MAX_TRY = 10
@@cleanlist = []
# Creates a temporary file of mode 0600 in the temporary directory,
# opens it with mode "w+", and returns a Tempfile object which
# represents the created temporary file. A Tempfile object can be
# treated just like a normal File object.
#
# The basename parameter is used to determine the name of a
# temporary file. If an Array is given, the first element is used
# as prefix string and the second as suffix string, respectively.
# Otherwise it is treated as prefix string.
#
# 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)
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
def make_tmpname(basename, n)
case basename
when Array
prefix, suffix = *basename
else
prefix, suffix = basename, ''
end
t = Time.now.strftime("%Y%m%d")
path = "#{prefix}#{t}-#{$$}-#{rand(0x100000000).to_s(36)}-#{n}#{suffix}"
end
private :make_tmpname
# Opens or reopens the file with mode "r+".
def open
@tmpfile.close if @tmpfile
@tmpfile = File.open(@tmpname, 'r+')
@data[1] = @tmpfile
__setobj__(@tmpfile)
end
def _close # :nodoc:
@tmpfile.close if @tmpfile
@tmpfile = nil
@data[1] = nil if @data
end
protected :_close
# Closes the file. If the optional flag is true, unlinks the file
# after closing.
#
# If you don't explicitly unlink the temporary file, the removal
# will be delayed until the object is finalized.
def close(unlink_now=false)
if unlink_now
close!
else
_close
end
end
# Closes and unlinks the file.
def close!
_close
@clean_proc.call
ObjectSpace.undefine_finalizer(self)
@data = @tmpname = nil
end
# Unlinks the file. On UNIX-like systems, it is often a good idea
# to unlink a temporary file immediately after creating and opening
# it, because it leaves other programs zero chance to access the
# file.
def unlink
# keep this order for thread safeness
begin
File.unlink(@tmpname) if File.exist?(@tmpname)
@@cleanlist.delete(@tmpname)
@data = @tmpname = nil
ObjectSpace.undefine_finalizer(self)
rescue Errno::EACCES
# may not be able to unlink on Windows; just ignore
end
end
alias delete unlink
# Returns the full path name of the temporary file.
def path
@tmpname
end
# Returns the size of the temporary file. As a side effect, the IO
# buffer is flushed before determining the size.
def size
if @tmpfile
@tmpfile.flush
@tmpfile.stat.size
else
0
end
end
alias length size
class << self
def callback(data) # :nodoc:
pid = $$
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
# 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.
def open(*args)
tempfile = new(*args)
if block_given?
begin
yield(tempfile)
ensure
tempfile.close
end
nil
else
tempfile
end
end
end
end
if __FILE__ == $0
# $DEBUG = true
f = Tempfile.new("foo")
f.print("foo\n")
f.close
f.open
p f.gets # => "foo\n"
f.close!
end
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