Attempt to recover journal automatically

mercurial/transaction.py

@@ -1,62 +1,65 b''
 # transaction.py - simple journalling scheme for mercurial
 #
 # This transaction scheme is intended to gracefully handle program
 # errors and interruptions. More serious failures like system crashes
 # can be recovered with an fsck-like tool. As the whole repository is
 # effectively log-structured, this should amount to simply truncating
 # anything that isn't referenced in the changelog.
 #
 # Copyright 2005 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms
 # of the GNU General Public License, incorporated herein by reference.
 
 import os
 
 class transaction:
     def __init__(self, opener, journal):
         self.opener = opener
         self.entries = []
         self.map = {}
         self.journal = journal
 
         # abort here if the journal already exists
         if os.path.exists(self.journal):
-            raise "Journal already exists!"
+            print "journal already exists, recovering"
+            self.recover()
+
         self.file = open(self.journal, "w")
 
     def __del__(self):
         if self.entries: self.abort()
         try: os.unlink(self.journal)
         except: pass
 
     def add(self, file, offset):
         if file in self.map: return
         self.entries.append((file, offset))
         self.map[file] = 1
         # add enough data to the journal to do the truncate
         self.file.write("%s\0%d\n" % (file, offset))
         self.file.flush()
 
     def close(self):
         self.file.close()
         self.entries = []
         os.unlink(self.journal)
 
     def abort(self):
         if not self.entries: return
 
         print "transaction abort!"
 
         for f, o in self.entries:
             self.opener(f, "a").truncate(o)
 
         self.entries = []
 
         print "rollback completed"
         
     def recover(self):
         for l in open(self.journal).readlines():
             f, o = l.split('\0')
             self.opener(f, "a").truncate(int(o))
+        os.unlink(self.journal)