tempfile: Add initial tempfile implementation.

With TemporaryDirectory class and mkdtemp function.

python-stdlib/tempfile/tempfile.py

@@ -0,0 +1,59 @@
+import errno
+import os
+import random
+import shutil
+
+_ascii_letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+
+
+def _get_candidate_name(size=8):
+    return "".join(random.choice(_ascii_letters) for _ in range(size))
+
+
+def _sanitize_inputs(suffix, prefix, dir):
+    if dir is None:
+        dir = "/tmp"
+    if suffix is None:
+        suffix = ""
+    if prefix is None:
+        prefix = ""
+    return suffix, prefix, dir
+
+
+def _try(action, *args, **kwargs):
+    try:
+        action(*args, **kwargs)
+        return True
+    except OSError as e:
+        if e.errno != errno.EEXIST:
+            raise e
+    return False
+
+
+def mkdtemp(suffix=None, prefix=None, dir=None):
+    suffix, prefix, dir = _sanitize_inputs(suffix, prefix, dir)
+
+    _try(os.mkdir, dir)
+
+    while True:
+        name = _get_candidate_name()
+        file = os.path.join(dir, prefix + name + suffix)
+        if _try(os.mkdir, file):
+            return file
+
+
+class TemporaryDirectory:
+    def __init__(self, suffix=None, prefix=None, dir=None):
+        self.name = mkdtemp(suffix, prefix, dir)
+
+    def __repr__(self):
+        return "<{} {!r}>".format(self.__class__.__name__, self.name)
+
+    def __enter__(self):
+        return self.name
+
+    def __exit__(self, exc, value, tb):
+        self.cleanup()
+
+    def cleanup(self):
+        _try(shutil.rmtree, self.name)