[Zope-Checkins] CVS: ZODB3/ZEO - cache.py:1.1.2.6

[Jeremy Hylton]

Update of /cvs-repository/ZODB3/ZEO
In directory cvs.zope.org:/tmp/cvs-serv11003/ZEO

Modified Files:
      Tag: ZODB3-mvcc-2-branch
	cache.py 
Log Message:
Fix bug in cache's version handling.

It returned version data even if requesting data for a different
version that the stored data used.


=== ZODB3/ZEO/cache.py 1.1.2.5 => 1.1.2.6 ===
--- ZODB3/ZEO/cache.py:1.1.2.5	Wed Nov 12 17:20:37 2003
+++ ZODB3/ZEO/cache.py	Thu Nov 13 13:44:58 2003
@@ -91,9 +91,8 @@
         # Maps oid to list of (start_tid, end_tid) pairs in sorted order.
         # Used to find matching key for load of non-current data.
         self.noncurrent = {}
-        # XXX I think oid, version can map to oid, tid without confusion.
-        # A transaction can write version data or non-version data,
-        # but not both.
+        # Map oid to version, tid pair.  If there is no entry, the object
+        # is not modified in a version.
         self.version = {}
 
         # A double-linked list is used to manage the cache.  It makes
@@ -117,7 +116,7 @@
                 break
             oid = o.key[0]
             if o.version:
-                self.version[oid] = o.start_tid
+                self.version[oid] = o.version, o.start_tid
             elif o.end_tid is None:
                 self.current[oid] = o.start_tid
             else:
@@ -169,7 +168,13 @@
     # @defreturn 3-tuple: (string, string, string)
 
     def load(self, oid, version=""):
-        tid = version and self.version.get(oid) or self.current.get(oid)
+        tid = None
+        if version:
+            p = self.version.get(oid)
+            if p is not None and p[0] == version:
+                tid = p[1]
+        if tid is None:
+            tid = self.current.get(oid)
         if tid is None:
             return None
         o = self.dll.access((oid, tid))
@@ -210,11 +215,11 @@
     # @defreturn string or None
 
     def modifiedInVersion(self, oid):
-        tid = self.version.get(oid)
-        if tid is None:
+        p = self.version.get(oid)
+        if p is None:
             return None
-        o = self.dll.access((oid, tid))
-        return o.version
+        version, tid = p
+        return version
 
     ##
     # Store a new data record in the cache.
@@ -235,7 +240,7 @@
         if version:
             if end_tid is not None:
                 raise ValueError("cache only stores current version data")
-            self.version[oid] = start_tid
+            self.version[oid] = version, start_tid
         else:
             if end_tid is None:
                 if oid in self.current:
@@ -299,10 +304,11 @@
             else:
                 del self.current[oid]
         else:
-            # XXX haven't handled non-current
+            # XXX Although we use bisect to keep the list sorted,
+            # we never expect the list to be very long.  So the
+            # brute force approach should normally be fine.
             L = self.noncurrent[oid]
-            i = bisect.bisect_left((o.start_end, o.end_tid))
-            print L, i
+            L.remove((o.start_tid, o.end_tid))
 
 ##
 # An object that's part of a headed, circular, doubly-linked list.