[Zodb-checkins] CVS: ZODB3/ZEO1 - ClientCache.py:1.2

[Guido van Rossum]

Update of /cvs-repository/ZODB3/ZEO1
In directory cvs.zope.org:/tmp/cvs-serv9856

Modified Files:
	ClientCache.py 
Log Message:
Fix the most egregious bugs (mirroring the fixes to ZEO2):

- Module docstring: document the persistent filenames correctly,
  mention magic.

- __init__(): correct seek to read the first record's serial.

- invalidate(): correct seek reversing from reading to writing.

- checkSize(): when flipping the cache, delete the index entries that
  are invalidated by this action.

- Normalize whitespace.


=== ZODB3/ZEO1/ClientCache.py 1.1.1.1 => 1.2 ===
--- ZODB3/ZEO1/ClientCache.py:1.1.1.1	Mon Aug 12 16:39:51 2002
+++ ZODB3/ZEO1/ClientCache.py	Wed Aug 28 18:10:48 2002
@@ -2,20 +2,21 @@
 #
 # Copyright (c) 2001, 2002 Zope Corporation and Contributors.
 # All Rights Reserved.
-# 
+#
 # This software is subject to the provisions of the Zope Public License,
 # Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
 # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
 # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
 # FOR A PARTICULAR PURPOSE
-# 
+#
 ##############################################################################
 """Implement a client cache
- 
-The cache is managed as two files, var/c0.zec and var/c1.zec.
 
-Each cache file is a sequence of records of the form:
+The cache is managed as two files, var/c<storage>-<client>-{0,1}.zec
+
+Each cache file has a 4-byte magic number followed by a sequence of
+records of the form:
 
   oid -- 8-byte object id
 
@@ -117,12 +118,12 @@
                     if fi.read(4)==magic: # Minimal sanity
                         fi.seek(0,2)
                         if fi.tell() > 30:
-                            fi.seek(22)
+                            fi.seek(23)
                             s[i]=fi.read(8)
                     # If we found a non-zero serial, then use the file
                     if s[i] != '\0\0\0\0\0\0\0\0': f[i]=fi
                     fi=None
-            
+
             # Whoever has the larger serial is the current
             if s[1] > s[0]: current=1
             elif s[0] > s[1]: current=0
@@ -174,7 +175,7 @@
             f.seek(ap)
             h=f.read(8)
             if h != oid: return
-            f.seek(8,1) # Dang, we shouldn't have to do this. Bad Solaris & NT
+            f.seek(p+8) # Switch from reading to writing
             if version:
                 f.write('n')
             else:
@@ -200,11 +201,11 @@
                 del self._index[oid]
                 return None
 
-            if h[8]=='n': 
+            if h[8]=='n':
                 if version: return None
                 if not dlen:
                     del self._index[oid]
-                    return None                
+                    return None
 
             if not vlen or not version:
                 if dlen: return read(dlen), h[19:]
@@ -248,7 +249,7 @@
                 if dlen:
                     p=read(dlen)
                     s=h[19:]
-                else: 
+                else:
                     return self._store(oid, '', '', version, data, serial)
 
                 self._store(oid, p, s, version, data, serial)
@@ -290,6 +291,11 @@
             if self._pos+size > self._limit:
                 current=not self._current
                 self._current=current
+                # Delete the half of the index that's no longer valid
+                index = self._index
+                for oid in index.keys():
+                    if (index[oid] < 0) == current:
+                        del index[oid]
                 if self._p[current] is not None:
                     # Persistent cache file:
                     # Note that due to permission madness, waaa,
@@ -308,7 +314,7 @@
                 self._f[current].write(magic)
                 self._pos=pos=4
         finally: self._release()
-        
+
 
     def store(self, oid, p, s, version, pv, sv):
         self._acquire()
@@ -386,14 +392,14 @@
                 # We have a record for this oid, but it was invalidated!
                 del serial[oid]
                 del index[oid]
-            
-            
+
+
         pos=pos+tlen
 
     f.seek(pos)
     try: f.truncate()
     except: pass
-    
+
     return pos
 
 def main(files):