locking: Implement opportunistic locking in LockSet

[ganeti-local] / lib / compat.py

diff --git a/lib/compat.py b/lib/compat.py
index 51ff904..6515af1 100644 (file)
--- a/lib/compat.py
+++ b/lib/compat.py
@@ -1,7 +1,7 @@
 #
 #
 
-# Copyright (C) 2010 Google Inc.
+# Copyright (C) 2010, 2011 Google Inc.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -24,13 +24,16 @@
 """
 
 import itertools
+import operator
 
 try:
+  # pylint: disable=F0401
   import functools
 except ImportError:
   functools = None
 
 try:
+  # pylint: disable=F0401
   import roman
 except ImportError:
   roman = None
@@ -42,10 +45,10 @@ except ImportError:
 # modules (hmac, for example) which have changed their behavior as well from
 # one version to the other.
 try:
+  # Yes, these don't always exist, that's why we're testing
   # Yes, we're not using the imports in this module.
-  # pylint: disable-msg=W0611
-  from hashlib import md5 as md5_hash
-  from hashlib import sha1 as sha1_hash
+  from hashlib import md5 as md5_hash # pylint: disable=W0611,E0611,F0401
+  from hashlib import sha1 as sha1_hash # pylint: disable=W0611,E0611,F0401
   # this additional version is needed for compatibility with the hmac module
   sha1 = sha1_hash
 except ImportError:
@@ -55,31 +58,40 @@ except ImportError:
   sha1_hash = sha.new
 
 
-def all(seq, pred=bool): # pylint: disable-msg=W0622
-  """Returns True if pred(x) is True for every element in the iterable.
-
-  Please note that this function provides a C{pred} parameter which isn't
-  available in the version included in Python 2.5 and above.
+def _all(seq):
+  """Returns True if all elements in the iterable are True.
 
   """
-  for _ in itertools.ifilterfalse(pred, seq):
+  for _ in itertools.ifilterfalse(bool, seq):
     return False
   return True
 
 
-def any(seq, pred=bool): # pylint: disable-msg=W0622
-  """Returns True if pred(x) is True for at least one element in the iterable.
-
-  Please note that this function provides a C{pred} parameter which isn't
-  available in the version included in Python 2.5 and above.
+def _any(seq):
+  """Returns True if any element of the iterable are True.
 
   """
-  for _ in itertools.ifilter(pred, seq):
+  for _ in itertools.ifilter(bool, seq):
     return True
   return False
 
 
-def partition(seq, pred=bool): # pylint: disable-msg=W0622
+try:
+  # pylint: disable=E0601
+  # pylint: disable=W0622
+  all = all
+except NameError:
+  all = _all
+
+try:
+  # pylint: disable=E0601
+  # pylint: disable=W0622
+  any = any
+except NameError:
+  any = _any
+
+
+def partition(seq, pred=bool): # pylint: disable=W0622
   """Partition a list in two, based on the given predicate.
 
   """
@@ -89,7 +101,7 @@ def partition(seq, pred=bool): # pylint: disable-msg=W0622
 
 # Even though we're using Python's built-in "partial" function if available,
 # this one is always defined for testing.
-def _partial(func, *args, **keywords): # pylint: disable-msg=W0622
+def _partial(func, *args, **keywords): # pylint: disable=W0622
   """Decorator with partial application of arguments and keywords.
 
   This function was copied from Python's documentation.
@@ -98,7 +110,7 @@ def _partial(func, *args, **keywords): # pylint: disable-msg=W0622
   def newfunc(*fargs, **fkeywords):
     newkeywords = keywords.copy()
     newkeywords.update(fkeywords)
-    return func(*(args + fargs), **newkeywords) # pylint: disable-msg=W0142
+    return func(*(args + fargs), **newkeywords) # pylint: disable=W0142
 
   newfunc.func = func
   newfunc.args = args
@@ -106,6 +118,12 @@ def _partial(func, *args, **keywords): # pylint: disable-msg=W0622
   return newfunc
 
 
+if functools is None:
+  partial = _partial
+else:
+  partial = functools.partial
+
+
 def TryToRoman(val, convert=True):
   """Try to convert a value to roman numerals
 
@@ -128,8 +146,8 @@ def TryToRoman(val, convert=True):
   else:
     return val
 
+#: returns the first element of a list-like value
+fst = operator.itemgetter(0)
 
-if functools is None:
-  partial = _partial
-else:
-  partial = functools.partial
+#: returns the second element of a list-like value
+snd = operator.itemgetter(1)