# 
# 
# patch "README"
#  from [1c7c6accbc0fca7adb5751504b36a252b110fefa]
#    to [26bd70117a1ed757aa23d0df7930e3f65e8ff207]
# 
# patch "tracvc/mtn/cache.py"
#  from [4a30ff0444dffafb15cdab7d65908b41b99692fd]
#    to [bc5c1e4f78fff49ac37e54464d7a7ead8b268037]
# 
============================================================
--- README	1c7c6accbc0fca7adb5751504b36a252b110fefa
+++ README	26bd70117a1ed757aa23d0df7930e3f65e8ff207
@@ -46,14 +46,18 @@
   * The full path to the Monotone binary can be specified using the
     'mtn_binary' option.
 
-  * A caching method for Monotone manifests, certs and changesets can
-    be specified using the 'cachespec' option. The format is:
-      cachespec = backend[:opt1[:opt2[...]]]
-    Currently two backends are provided:
+  * A caching method for Monotone manifests, certs, changesets,
+    etc. can be specified using the 'cachespec' option. The format is:
+      cachespec = backend[:option1[:option2[...]]]
+    
+    Currently these backends are provided:
     - 'localmem': (default) uses local memory for caching. Takes no
-      options.
+       options.
     - 'dbmshelve:prefix': Persistent, uses Unix DBM databases named
-      prefix*.{pag|dir}. All directories in prefix must exist.
+       prefix*.{pag|dir}. All directories in prefix must exist. Not suited
+       for concurrent access by more than one process.
+    - 'bsddb:dir:prefix': Uses the bsddb3 binding to a persistent
+       BerkeleyDB database. The directory 'dir' must be writable by trac.
 
 
 Known Problems/Missing Features
============================================================
--- tracvc/mtn/cache.py	4a30ff0444dffafb15cdab7d65908b41b99692fd
+++ tracvc/mtn/cache.py	bc5c1e4f78fff49ac37e54464d7a7ead8b268037
@@ -26,8 +26,6 @@
     from threading import Lock
 except ImportError:
     from dummy_threading import Lock
-from shelve import Shelf
-import dbm
 
 
 class Cache(object):
@@ -151,9 +149,12 @@
     """Using Python's shelve on a DBM database."""
 
     def __init__(self, realm, prefix):
-        LocalMem.__init__(self, realm)
+        import shelve
+        import dbm
+
         self.dbname = prefix + realm
-        self.cache = Shelf(dbm.open(self.dbname, 'c'))
+        self.cache = shelve.Shelf(dbm.open(self.dbname, 'c'))
+        self.lock = Lock()
 
     def __del__(self):
         self.cache.close()
@@ -164,6 +165,38 @@
 Cache.add_backend('dbmshelve', DBMShelve)
 
 
+class BSDDBShelve(Cache):
+    """Using the bsddb3 interface to db."""
+
+    dbenv = None
+
+    @classmethod
+    def get_env(self, dir):
+        if not self.dbenv:
+            from bsddb3 import db
+            self.dbenv = db.DBEnv()
+            self.dbenv.open(dir,
+                db.DB_INIT_CDB|db.DB_INIT_MPOOL|db.DB_CREATE)
+        return self.dbenv
+
+    def __init__(self, realm, dir, prefix=''):
+        from bsddb3 import dbshelve
+        self.dbname = prefix + realm
+        self.cache = dbshelve.open(self.dbname, dbenv=self.get_env(dir))
+        
+    def set(self, key, value):
+        self.cache[key] = value
+
+    def add(self, key, value):
+        # FIXME wrong semantics
+        self.cache[key] = value
+
+    def get(self, key):
+        return self.cache[key]
+
+Cache.add_backend('bsddb', BSDDBShelve)
+
+
 def memoize(get_cachespec, realm = None):
     """Decorates a method with the Memoize decorator. get_cachespec is
     a method of the same class which returns the desired cachespec,
@@ -174,7 +207,7 @@
 class Memoize(object):
     """Caches return values of the decorated method."""
 
-    def __init__(self, function, get_cachespec, realm = None):
+    def __init__(self, function, get_cachespec, realm):
         self.function = function
         self.get_cachespec = get_cachespec
         self.realm = realm or function.__name__