added compat.aliased lazy-loading module, aliases for BytesIO/StringIO

4 files changed, 55 insertions, 16 deletions

diff --git a/passlib/utils/__init__.py b/passlib/utils/__init__.py
index 40a53b9..e8be491 100644
--- a/passlib/utils/__init__.py
+++ b/passlib/utils/__init__.py
@@ -5,7 +5,6 @@
 #core
 from base64 import b64encode, b64decode
 from codecs import lookup as _lookup_codec
-from cStringIO import StringIO
 ##from functools import update_wrapper
 from hashlib import sha256
 import logging; log = logging.getLogger(__name__)
diff --git a/passlib/utils/_blowfish/__init__.py b/passlib/utils/_blowfish/__init__.py
index a1f3695..dff1ca5 100644
--- a/passlib/utils/_blowfish/__init__.py
+++ b/passlib/utils/_blowfish/__init__.py
@@ -51,11 +51,12 @@ released under the BSD license::
 #imports
 #=========================================================
 #core
-from cStringIO import StringIO
 from itertools import chain
 import struct
 #pkg
-from passlib.utils import rng, getrandbytes, bytes, bord, b
+from passlib.utils import rng, getrandbytes, bytes, bord
+from passlib.utils.compat import b
+from passlib.utils.compat.aliases import BytesIO
 from passlib.utils._blowfish.unrolled import BlowfishEngine
 #local
 __all__ = [
@@ -81,7 +82,7 @@ digest_struct = struct.Struct(">6I")
 #=========================================================
 
 # Table for Base64 encoding
-CHARS = "./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"
+CHARS = b("./ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789")
 CHARSIDX = dict( (c, i) for i, c in enumerate(CHARS))
 
 def encode_base64(d):
@@ -98,7 +99,7 @@ def encode_base64(d):
         d = d.encode("utf-8")
         #ensure ord() returns something w/in 0..255
 
-    rs = StringIO()
+    rs = BytesIO()
     write = rs.write
     dlen = len(d)
     didx = 0
@@ -144,7 +145,7 @@ def decode_base64(s):
     :raises ValueError:
         if invalid values are passed in
     """
-    rs = StringIO()
+    rs = BytesIO()
     write = rs.write
     slen = len(s)
     sidx = 0
diff --git a/passlib/utils/compat.py b/passlib/utils/compat.py
index 44e9302..96a7ae0 100644
--- a/passlib/utils/compat.py
+++ b/passlib/utils/compat.py
@@ -29,6 +29,52 @@ del logb
 assert sys_bits in (32,64), "unexpected system bitsize: %r" % (sys_bits,)
 
 #=============================================================================
+# lazy import aliases
+#=============================================================================
+if PY3:
+    _aliases = dict(
+        BytesIO="io.BytesIO",
+        StringIO="io.StringIO",
+        SafeConfigParser="configparser.SafeConfigParser",
+    )
+    if PY_MIN_32:
+        # py32 renamed this, removing old ConfigParser
+        _aliases["SafeConfigParser"] = "configparser.ConfigParser"
+else:
+    _aliases = dict(
+        BytesIO="cStringIO.StringIO",
+        StringIO="StringIO.StringIO",
+        SafeConfigParser="ConfigParser.SafeConfigParser",
+    )
+
+from types import ModuleType
+class _AliasedModule(ModuleType):
+    "fake module that does lazy importing of attributes"
+
+    def __init__(self, name, **source):
+        ModuleType.__init__(self, name)
+        self._source = source
+
+    def __getattr__(self, attr):
+        source = self._source
+        if attr in source:
+            modname, modattr = source[attr].rsplit(".",1)
+            mod = __import__(modname, fromlist=[modattr], level=0)
+            value = getattr(mod, modattr)
+            setattr(self, attr, value)
+            return value
+        return types.ModuleType.__getattr__(self, attr)
+
+    def __dir__(self):
+        attrs = set(dir(self.__class__))
+        attrs.update(self.__dict__)
+        attrs.update(self._source)
+        return list(attrs)
+
+aliases = _AliasedModule(__name__ + ".aliases", **_aliases)
+sys.modules[aliases.__name__] = aliases
+
+#=============================================================================
 # typing
 #=============================================================================
 def is_mapping(obj):
@@ -59,6 +105,7 @@ if PY3:
     unicode = str
     __all__.append("unicode")
 #    string_types = (str,)
+
 else:
     def u(s):
         return s.decode("unicode_escape")
@@ -72,9 +119,6 @@ else:
 
 sb_types = (unicode, bytes)
 
-#=============================================================================
-# bytes-specific helpers
-#=============================================================================
 # bytes format
 
 #=============================================================================
@@ -125,7 +169,7 @@ else:
         return method.im_func
 
 #=============================================================================
-# output
+# input/output
 #=============================================================================
 if PY3:
     import builtins
diff --git a/passlib/utils/pbkdf2.py b/passlib/utils/pbkdf2.py
index 9a7ee7c..aa35327 100644
--- a/passlib/utils/pbkdf2.py
+++ b/passlib/utils/pbkdf2.py
@@ -22,6 +22,7 @@ except ImportError:
 #pkg
 from passlib.utils import xor_bytes, to_bytes, native_str, b, bytes
 from passlib.utils.compat import irange, callable, int_types
+from passlib.utils.compat.aliases import BytesIO
 #local
 __all__ = [
     "hmac_sha1",
@@ -30,12 +31,6 @@ __all__ = [
     "pbkdf2",
 ]
 
-# Py2k #
-from cStringIO import StringIO as BytesIO
-# Py3k #
-#from io import BytesIO
-# end Py3k #
-
 #=================================================================================
 #quick hmac_sha1 implementation used various places
 #=================================================================================