[Zodb-checkins] CVS: StandaloneZODB/ZODB - FileStorage.py:1.71.2.1

[Jeremy Hylton]

Update of /cvs-repository/StandaloneZODB/ZODB
In directory cvs.zope.org:/tmp/cvs-serv25557

Modified Files:
      Tag: jeremy-Standby-branch
	FileStorage.py 
Log Message:
Extended iterator() call to support optional start and stop arguments.
Add lastTransaction() method.


=== StandaloneZODB/ZODB/FileStorage.py 1.71 => 1.71.2.1 ===
                 read_only=read_only,
                 )
+        self._ltid = tid
 
         self._ts=tid=TimeStamp(tid)
         t=time.time()
@@ -798,6 +799,7 @@
 
             self._index.update(self._tindex)
             self._vindex.update(self._tvindex)
+        self._ltid = tid
 
     def _abort(self):
         if self._nextpos:
@@ -1592,8 +1594,11 @@
             self._packt=z64
             _lock_release()
 
-    def iterator(self):
-        return FileIterator(self._file_name)
+    def iterator(self, start=None, stop=None):
+        return FileIterator(self._file_name, start, stop)
+
+    def lastTransaction(self):
+        return self._ltid
 
 def shift_transactions_forward(index, vindex, tindex, file, pos, opos):
     """Copy transactions forward in the data file
@@ -2010,7 +2015,7 @@
     """
     _ltid=z64
     
-    def __init__(self, file):
+    def __init__(self, file, start=None, stop=None):
         if isinstance(file, StringType):
             file=open(file, 'rb')
         self._file=file
@@ -2018,6 +2023,29 @@
         file.seek(0,2)
         self._file_size=file.tell()
         self._pos=4L
+        if start:
+            self._skip_to_start(start)
+        self._stop = stop
+
+    def _skip_to_start(self, start):
+        # Scan through the transaction records doing almost no sanity
+        # checks. 
+        self._file.seek(self._pos)
+        while 1:
+            h = self._file.read(8)
+            if len(h) < 8:
+                return
+            tid, stl = unpack(">8s8s", h)
+            tl = U64(stl)
+            if tid >= start:
+                self._file.seek(-8, 1)
+                return
+            self._file.seek(tl - 8)
+            rtl = self._file.read(8)
+            if rtl != stl:
+                pos = self._file.tell() - 8
+                panic("%s has inconsistent transaction length at %s",
+                      self._file.name, pos)
 
     def next(self, index=0):
         file=self._file
@@ -2072,6 +2100,9 @@
                 else:
                     warn('%s has invalid transaction header at %s', name, pos)
                     break
+
+            if self._stop is not None and tid >= self._stop:
+                raise IndexError, index
 
             tpos=pos
             tend=tpos+tl