This allows using a "with statement" together with instances of
atomic_ofstream. Allowing for more readable, less error prone and
shorter code.
Signed-off-by: Florian Schmaus <f...@geekplace.eu>
---
lib/portage/util/__init__.py | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/lib/portage/util/__init__.py b/lib/portage/util/__init__.py
index 0412b2b5911f..bedcbcfe6fcc 100644
--- a/lib/portage/util/__init__.py
+++ b/lib/portage/util/__init__.py
@@ -11,6 +11,7 @@ __all__ = ['apply_permissions', 'apply_recursive_permissions',
'stack_dicts', 'stack_lists', 'unique_array', 'unique_everseen',
'varexpand',
'write_atomic', 'writedict', 'writemsg', 'writemsg_level',
'writemsg_stdout']
+from contextlib import AbstractContextManager
from copy import deepcopy
import errno
import io
@@ -1246,7 +1247,7 @@ def apply_secpass_permissions(filename, uid=-1, gid=-1,
mode=-1, mask=-1,
stat_cached=stat_cached, follow_links=follow_links)
return all_applied
-class atomic_ofstream(ObjectProxy):
+class atomic_ofstream(AbstractContextManager, ObjectProxy):
"""Write a file atomically via os.rename(). Atomic replacement prevents
interprocess interference and prevents corruption of the target
file when the write is interrupted (for example, when an 'out of space'
@@ -1287,6 +1288,13 @@ class atomic_ofstream(ObjectProxy):
encoding=_encodings['fs'], errors='strict'),
mode=mode, **kargs))
+ def __exit__(self, exc_type, exc_val, exc_tb):
+ if exc_type is not None:
+ self.abort()
+ else:
+ self.close()
+ return None
+
def _get_target(self):
return object.__getattribute__(self, '_file')
--
2.26.2
