[gobject-introspection] cachestore: Use "write new, then rename" pattern, not "write in place"

[Colin Walters <walters src gnome org>]

commit 5b105135d27ea2f06e8863de813112611955290d
Author: Colin Walters <walters verbum org>
Date:   Thu Feb 27 09:01:14 2014 -0500

    cachestore: Use "write new, then rename" pattern, not "write in place"
    
    This should fix race conditions when multiple processes attempt to
    access the cache concurrently.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=724886

 giscanner/cachestore.py |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)
---
diff --git a/giscanner/cachestore.py b/giscanner/cachestore.py
index ad4c7a3..27b260f 100644
--- a/giscanner/cachestore.py
+++ b/giscanner/cachestore.py
@@ -100,9 +100,11 @@ class CacheStore(object):
         if current_hash == cache_hash:
             return
 
+        versiontmp = version + '.tmp'
+
         self._clean()
         try:
-            fp = open(version, 'w')
+            fp = open(versiontmp, 'w')
         except IOError as e:
             # Permission denied
             if e.errno == errno.EACCES:
@@ -111,6 +113,10 @@ class CacheStore(object):
                 raise
 
         fp.write(current_hash)
+        fp.close()
+        # On Unix, this would just be os.rename() but Windows
+        # doesn't allow that.
+        shutil.move(versiontmp, version)
 
     def _get_filename(self, filename):
         # If we couldn't create the directory we're probably