diff --git a/Lib/tempfile.py b/Lib/tempfile.py
index 0ebf6b4..b63a46a 100644
--- a/Lib/tempfile.py
+++ b/Lib/tempfile.py
@@ -19,6 +19,7 @@
 
 __all__ = [
     "NamedTemporaryFile", "TemporaryFile", # high level safe interfaces
+    "SpooledTemporaryFile",
     "mkstemp", "mkdtemp",                  # low level safe interfaces
     "mktemp",                              # deprecated unsafe interface
     "TMP_MAX", "gettempprefix",            # constants
@@ -37,6 +38,11 @@
     import Carbon.Folders as _Folders
 
 try:
+    from cStringIO import StringIO as _StringIO
+except:
+    from StringIO import StringIO as _StringIO
+
+try:
     import fcntl as _fcntl
 except ImportError:
     def _set_cloexec(fd):
@@ -114,7 +120,7 @@
 
     characters = ("abcdefghijklmnopqrstuvwxyz" +
                   "ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
-                  "0123456789-_")
+                  "0123456789_")
 
     def __init__(self):
         self.mutex = _allocate_lock()
@@ -372,10 +378,11 @@
     remove the file when it is no longer needed.
     """
 
-    def __init__(self, file, name):
+    def __init__(self, file, name, delete=True):
         self.file = file
         self.name = name
         self.close_called = False
+        self.delete = delete
 
     def __getattr__(self, name):
         file = self.__dict__['file']
@@ -400,23 +407,25 @@
             if not self.close_called:
                 self.close_called = True
                 self.file.close()
-                self.unlink(self.name)
+                if self.delete:
+                    self.unlink(self.name)
 
         def __del__(self):
             self.close()
 
 def NamedTemporaryFile(mode='w+b', bufsize=-1, suffix="",
-                       prefix=template, dir=None):
+                       prefix=template, dir=None, delete=True):
     """Create and return a temporary file.
     Arguments:
     'prefix', 'suffix', 'dir' -- as for mkstemp.
     'mode' -- the mode argument to os.fdopen (default "w+b").
     'bufsize' -- the buffer size argument to os.fdopen (default -1).
+    'delete' -- whether the file is deleted on close (default True).
     The file is created as mkstemp() would do it.
 
     Returns an object with a file-like interface; the name of the file
     is accessible as file.name.  The file will be automatically deleted
-    when it is closed.
+    when it is closed unless the 'delete' argument is set to False.
     """
 
     if dir is None:
@@ -429,12 +438,12 @@
 
     # Setting O_TEMPORARY in the flags causes the OS to delete
     # the file when it is closed.  This is only supported by Windows.
-    if _os.name == 'nt':
+    if _os.name == 'nt' and delete:
         flags |= _os.O_TEMPORARY
 
     (fd, name) = _mkstemp_inner(dir, prefix, suffix, flags)
     file = _os.fdopen(fd, mode, bufsize)
-    return _TemporaryFileWrapper(file, name)
+    return _TemporaryFileWrapper(file, name, delete)
 
 if _os.name != 'posix' or _os.sys.platform == 'cygwin':
     # On non-POSIX and Cygwin systems, assume that we cannot unlink a file
@@ -470,3 +479,111 @@
         except:
             _os.close(fd)
             raise
+
+class SpooledTemporaryFile:
+    """Temporary file wrapper, specialized to switch from
+    StringIO to a real file when it exceeds a certain size or
+    when a fileno is needed.
+    """
+    _rolled = False
+
+    def __init__(self, max_size=0, mode='w+b', bufsize=-1,
+                 suffix="", prefix=template, dir=None):
+        self._file = _StringIO()
+        self._max_size = max_size
+        self._rolled = False
+        self._TemporaryFileArgs = (mode, bufsize, suffix, prefix, dir)
+
+    def _check(self, file):
+        if self._rolled: return
+        max_size = self._max_size
+        if max_size and file.tell() > max_size:
+            self.rollover()
+
+    def rollover(self):
+        if self._rolled: return
+        file = self._file
+        newfile = self._file = TemporaryFile(*self._TemporaryFileArgs)
+        del self._TemporaryFileArgs
+
+        newfile.write(file.getvalue())
+        newfile.seek(file.tell(), 0)
+
+        self._rolled = True
+
+    # file protocol
+    def __iter__(self):
+        return self._file.__iter__()
+
+    def close(self):
+        self._file.close()
+
+    @property
+    def closed(self):
+        return self._file.closed
+
+    @property
+    def encoding(self):
+        return self._file.encoding
+
+    def fileno(self):
+        self.rollover()
+        return self._file.fileno()
+
+    def flush(self):
+        self._file.flush()
+
+    def isatty(self):
+        return self._file.isatty()
+
+    @property
+    def mode(self):
+        return self._file.mode
+
+    @property
+    def name(self):
+        return self._file.name
+
+    @property
+    def newlines(self):
+        return self._file.newlines
+
+    def next(self):
+        return self._file.next
+
+    def read(self, *args):
+        return self._file.read(*args)
+
+    def readline(self, *args):
+        return self._file.readline(*args)
+
+    def readlines(self, *args):
+        return self._file.readlines(*args)
+
+    def seek(self, *args):
+        self._file.seek(*args)
+
+    @property
+    def softspace(self):
+        return self._file.softspace
+
+    def tell(self):
+        return self._file.tell()
+
+    def truncate(self):
+        self._file.truncate()
+
+    def write(self, s):
+        file = self._file
+        rv = file.write(s)
+        self._check(file)
+        return rv
+
+    def writelines(self, iterable):
+        file = self._file
+        rv = file.writelines(iterable)
+        self._check(file)
+        return rv
+
+    def xreadlines(self, *args):
+        return self._file.xreadlines(*args)