Skip to content
This repository
Fetching contributors…

Octocat-spinner-32-eaf2f5

Cannot retrieve contributors at this time

file 347 lines (324 sloc) 10.517 kb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346
#
# tempfile - manipulates temporary files
#
# $Id: tempfile.rb 27578 2010-05-01 13:54:01Z nobu $
#

require 'delegate'
require 'tmpdir'
require 'thread'

# A utility class for managing temporary files. When you create a Tempfile
# object, it will create a temporary file with a unique filename. A Tempfile
# objects behaves just like a File object, and you can perform all the usual
# file operations on it: reading data, writing data, changing its permissions,
# etc. So although this class does not explicitly document all instance methods
# supported by File, you can in fact call any File instance method on a
# Tempfile object.
#
# == Synopsis
#
# require 'tempfile'
#
# file = Tempfile.new('foo')
# file.path # => A unique filename in the OS's temp directory,
# # e.g.: "/tmp/foo.24722.0"
# # This filename contains 'foo' in its basename.
# file.write("hello world")
# file.rewind
# file.read # => "hello world"
# file.close
# file.unlink # deletes the temp file
#
# == Good practices
#
# === Explicit close
#
# When a Tempfile object is garbage collected, or when the Ruby interpreter
# exits, its associated temporary file is automatically deleted. This means
# that's it's unnecessary to explicitly delete a Tempfile after use, though
# it's good practice to do so: not explicitly deleting unused Tempfiles can
# potentially leave behind large amounts of tempfiles on the filesystem
# until they're garbage collected. The existance of these temp files can make
# it harder to determine a new Tempfile filename.
#
# Therefore, one should always call #unlink or close in an ensure block, like
# this:
#
# file = Tempfile.new('foo')
# begin
# ...do something with file...
# ensure
# file.close
# file.unlink # deletes the temp file
# end
#
# === Unlink after creation
#
# On POSIX systems, it's possible to unlink a file right after creating it,
# and before closing it. This removes the filesystem entry without closing
# the file handle, so it ensures that only the processes that already had
# the file handle open can access the file's contents. It's strongly
# recommended that you do this if you do not want any other processes to
# be able to read from or write to the Tempfile, and you do not need to
# know the Tempfile's filename either.
#
# For example, a practical use case for unlink-after-creation would be this:
# you need a large byte buffer that's too large to comfortably fit in RAM,
# e.g. when you're writing a web server and you want to buffer the client's
# file upload data.
#
# Please refer to #unlink for more information and a code example.
#
# == Minor notes
#
# Tempfile's filename picking method is both thread-safe and inter-process-safe:
# it guarantees that no other threads or processes will pick the same filename.
#
# Tempfile itself however may not be entirely thread-safe. If you access the
# same Tempfile object from multiple threads then you should protect it with a
# mutex.
class Tempfile < DelegateClass(File)
  MAX_TRY = 10 # :nodoc:
  include Dir::Tmpname

  # call-seq:
  # new(basename, [tmpdir = Dir.tmpdir], [options])
  #
  # Creates a temporary file with permissions 0600 (= only readable and
  # writable by the owner) and opens it with mode "w+".
  #
  # The +basename+ parameter is used to determine the name of the
  # temporary file. You can either pass a String or an Array with
  # 2 String elements. In the former form, the temporary file's base
  # name will begin with the given string. In the latter form,
  # the temporary file's base name will begin with the array's first
  # element, and end with the second element. For example:
  #
  # file = Tempfile.new('hello')
  # file.path # => something like: "/tmp/foo2843-8392-92849382--0"
  #
  # # Use the Array form to enforce an extension in the filename:
  # file = Tempfile.new(['hello', '.jpg'])
  # file.path # => something like: "/tmp/foo2843-8392-92849382--0.jpg"
  #
  # The temporary file will be placed in the directory as specified
  # by the +tmpdir+ parameter. By default, this is +Dir.tmpdir+.
  # When $SAFE > 0 and the given +tmpdir+ is tainted, it uses
  # '/tmp' as the temporary directory. Please note that ENV values
  # are tainted by default, and +Dir.tmpdir+'s return value might
  # come from environment variables (e.g. <tt>$TMPDIR</tt>).
  #
  # file = Tempfile.new('hello', '/home/aisaka')
  # file.path # => something like: "/home/aisaka/foo2843-8392-92849382--0"
  #
  # You can also pass an options hash. Under the hood, Tempfile creates
  # the temporary file using +File.open+. These options will be passed to
  # +File.open+. This is mostly useful for specifying encoding
  # options, e.g.:
  #
  # Tempfile.new('hello', '/home/aisaka', :encoding => 'ascii-8bit')
  #
  # # You can also omit the 'tmpdir' parameter:
  # Tempfile.new('hello', :encoding => 'ascii-8bit')
  #
  # === Exceptions
  #
  # If Tempfile.new cannot find a unique filename within a limited
  # number of tries, then it will raise an exception.
  def initialize(basename, *rest)
    @data = []
    @clean_proc = Remover.new(@data)
    ObjectSpace.define_finalizer(self, @clean_proc)

    create(basename, *rest) do |tmpname, n, opts|
      lock = tmpname + '.lock'
      mode = File::RDWR|File::CREAT|File::EXCL
      perm = 0600
      if opts
        mode |= opts.delete(:mode) || 0
        opts[:perm] = perm
        perm = nil
      else
        opts = perm
      end
      self.class.mkdir(lock)
      begin
        @data[1] = @tmpfile = File.open(tmpname, mode, opts)
        @data[0] = @tmpname = tmpname
      ensure
        self.class.rmdir(lock)
      end
      @mode = mode & ~(File::CREAT|File::EXCL)
      perm or opts.freeze
      @opts = opts
    end

    super(@tmpfile)
  end

  # Opens or reopens the file with mode "r+".
  def open
    @tmpfile.close if @tmpfile
    @tmpfile = File.open(@tmpname, @mode, @opts)
    @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 +unlink_now+ is true, then the file will be unlinked
  # (deleted) after closing. Of course, you can choose to later call #unlink
  # if you do not unlink it now.
  #
  # 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 (deletes) the file. Has the same effect as called
  # <tt>close(true)</tt>.
  def close!
    _close
    unlink
    ObjectSpace.undefine_finalizer(self)
  end

  # Unlinks (deletes) the file from the filesystem. One should always unlink
  # the file after using it, as is explained in the "Explicit close" good
  # practice section in the Tempfile overview:
  #
  # file = Tempfile.new('foo')
  # begin
  # ...do something with file...
  # ensure
  # file.close
  # file.unlink # deletes the temp file
  # end
  #
  # === Unlink-before-close
  #
  # On POSIX systems it's possible to unlink a file before closing it. This
  # practice is explained in detail in the Tempfile overview (section
  # "Unlink after creation"); please refer there for more information.
  #
  # However, unlink-before-close may not be supported on non-POSIX operating
  # systems. Microsoft Windows is the most notable case: unlinking a non-closed
  # file will result in an error, which this method will silently ignore. If
  # you want to practice unlink-before-close whenever possible, then you should
  # write code like this:
  #
  # file = Tempfile.new('foo')
  # file.unlink # On Windows this silently fails.
  # begin
  # ... do something with file ...
  # ensure
  # file.close! # Closes the file handle. If the file wasn't unlinked
  # # because #unlink failed, then this method will attempt
  # # to do so again.
  # end
  def unlink
    # keep this order for thread safeness
    return unless @tmpname
    begin
      if File.exist?(@tmpname)
        File.unlink(@tmpname)
      end
      # remove tmpname from remover
      @data[0] = @data[2] = nil
      @data = @tmpname = nil
    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.
  # This will be nil if #unlink has been called.
  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
    elsif @tmpname
      File.size(@tmpname)
    else
      0
    end
  end
  alias length size

  # :stopdoc:
  class Remover
    def initialize(data)
      @pid = $$
      @data = data
    end

    def call(*args)
      if @pid == $$
        path, tmpfile = *@data

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

        tmpfile.close if tmpfile

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

        STDERR.print "done\n" if $DEBUG
      end
    end
  end
  # :startdoc:

  class << self
    # Creates a new Tempfile.
    #
    # If no block is given, this is a synonym for Tempfile.new.
    #
    # If a block is given, then a Tempfile object will be constructed,
    # and the block is run with said object as argument. The Tempfile
    # oject will be automatically closed after the block terminates.
    # The call returns the value of the block.
    #
    # In any case, all arguments (+*args+) will be passed to Tempfile.new.
    #
    # Tempfile.open('foo', '/home/temp') do |f|
    # ... do something with f ...
    # end
    #
    # # Equivalent:
    # f = Tempfile.open('foo', '/home/temp')
    # begin
    # ... do something with f ...
    # ensure
    # f.close
    # end
    def open(*args)
      tempfile = new(*args)

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

    def mkdir(*args)
      Dir.mkdir(*args)
    end
    def rmdir(*args)
      Dir.rmdir(*args)
    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
Something went wrong with that request. Please try again.