From 806e20fd8cc68c07301005c3e8237c5cacec5ba1 Mon Sep 17 00:00:00 2001
From: Guido Trotter <ultrotter@google.com>
Date: Tue, 4 Mar 2008 13:18:03 +0000
Subject: [PATCH] LockSet: encapsulate acquire() in try-except
This patch adds a try/except area around most of the acquire() code (everything
after the intial condition checks). Since the except: clause contains just a
'raise' nothing really changes except the indentation of the code.
This is done in a separate commit to insulate and make clearer what the real
code changes done in the upcoming patch are.
Reviewed-by: imsnah
---
lib/locking.py | 86 ++++++++++++++++++++++++++------------------------
1 file changed, 45 insertions(+), 41 deletions(-)
diff --git a/lib/locking.py b/lib/locking.py
index f9b1cfcce..7c886a5da 100644
--- a/lib/locking.py
+++ b/lib/locking.py
@@ -372,49 +372,53 @@ class LockSet:
# Check we don't already own locks at this level
assert not self._is_owned(), "Cannot acquire locks in the same set twice"
- # Support passing in a single resource to acquire rather than many
- if isinstance(names, basestring):
- names = [names]
- else:
- names.sort()
+ try:
+ # Support passing in a single resource to acquire rather than many
+ if isinstance(names, basestring):
+ names = [names]
+ else:
+ names.sort()
- acquire_list = []
- # First we look the locks up on __lockdict. We have no way of being sure
- # they will still be there after, but this makes it a lot faster should
- # just one of them be the already wrong
- for lname in names:
- try:
- lock = self.__lockdict[lname] # raises KeyError if the lock is not there
- acquire_list.append((lname, lock))
- except (KeyError):
- raise errors.LockError('non-existing lock in set (%s)' % lname)
-
- # This will hold the locknames we effectively acquired.
- acquired = set()
- # Now acquire_list contains a sorted list of resources and locks we want.
- # In order to get them we loop on this (private) list and acquire() them.
- # We gave no real guarantee they will still exist till this is done but
- # .acquire() itself is safe and will alert us if the lock gets deleted.
- for (lname, lock) in acquire_list:
- try:
- lock.acquire(shared=shared) # raises LockError if the lock is deleted
+ acquire_list = []
+ # First we look the locks up on __lockdict. We have no way of being sure
+ # they will still be there after, but this makes it a lot faster should
+ # just one of them be the already wrong
+ for lname in names:
try:
- # now the lock cannot be deleted, we have it!
- self._add_owned(lname)
- acquired.add(lname)
- except:
- # We shouldn't have problems adding the lock to the owners list, but
- # if we did we'll try to release this lock and re-raise exception.
- # Of course something is going to be really wrong, after this.
- lock.release()
- raise
-
- except (errors.LockError):
- name_fail = lname
- for lname in self._list_owned():
- self.__lockdict[lname].release()
- self._del_owned(lname)
- raise errors.LockError('non-existing lock in set (%s)' % name_fail)
+ lock = self.__lockdict[lname] # raises KeyError if the lock is not there
+ acquire_list.append((lname, lock))
+ except (KeyError):
+ raise errors.LockError('non-existing lock in set (%s)' % lname)
+
+ # This will hold the locknames we effectively acquired.
+ acquired = set()
+ # Now acquire_list contains a sorted list of resources and locks we want.
+ # In order to get them we loop on this (private) list and acquire() them.
+ # We gave no real guarantee they will still exist till this is done but
+ # .acquire() itself is safe and will alert us if the lock gets deleted.
+ for (lname, lock) in acquire_list:
+ try:
+ lock.acquire(shared=shared) # raises LockError if the lock is deleted
+ try:
+ # now the lock cannot be deleted, we have it!
+ self._add_owned(lname)
+ acquired.add(lname)
+ except:
+ # We shouldn't have problems adding the lock to the owners list, but
+ # if we did we'll try to release this lock and re-raise exception.
+ # Of course something is going to be really wrong, after this.
+ lock.release()
+ raise
+
+ except (errors.LockError):
+ name_fail = lname
+ for lname in self._list_owned():
+ self.__lockdict[lname].release()
+ self._del_owned(lname)
+ raise errors.LockError('non-existing lock in set (%s)' % name_fail)
+
+ except:
+ raise
return acquired
--
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