python/lock.cc: Implement apt_pkg.FileLock().

This is yet another context manager, this time for locking files. It can
be used multiple times and features an internal counter.

1 files changed, 6 insertions, 0 deletions

diff --git a/doc/source/whatsnew/0.8.0.rst b/doc/source/whatsnew/0.8.0.rst
index 8889cbd9..244da388 100644
--- a/doc/source/whatsnew/0.8.0.rst
+++ b/doc/source/whatsnew/0.8.0.rst
@@ -79,6 +79,12 @@ Yet another context manager is available for locking the package system::
     with apt_pkg.SystemLock():
         # do your stuff here
 
+There is also one for file based locking:
+
+    with apt_pkg.FileLock(filename):
+        # do your stuff here
+
+
 Unification of dependency handling
 ----------------------------------
 In apt 0.7, there were three different return types of functions parsing