offlineimap rev 474

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Author: jgoerzen
Date: 2003-05-06 09:26:12 -0500 (Tue, 06 May 2003)
New Revision: 474

Modified:
  offlineimap/head/debian/changelog
  offlineimap/head/offlineimap/folder/Maildir.py

Log:
offlineimap (3.99.17) unstable; urgency=low

  * Fixed two potential obscure race conditions in folder/Maildir.py.
    + Condition 1 involved the gettimeseq() function.  This function
      accesses per-module variables but does not have a lock.  It may have  
      been possible for this to have been called in such a way that timeseq 
      was not properly updated.                           
    + Condition 2 involved the call to gettimeseq().  Since the timeseq is  
      based on the system clock, we now use the time as reported inside
      timeseq() rather than outside.  This way, we can be assured that the
      same value is in use both places.                   
  * Added debug code to savemessage in folder/Maildir.py to try to track
    down a mysterious 0-length file bug.

 -- John Goerzen <[email protected]>  Tue,  6 May 2003 09:21:38 -0500



Diff:
Modified: offlineimap/head/debian/changelog
==============================================================================
--- offlineimap/head/debian/changelog	(original)
+++ offlineimap/head/debian/changelog	2003-05-06 09:26:18.000000000 -0500
@@ -1,3 +1,19 @@
+offlineimap (3.99.17) unstable; urgency=low
+
+  * Fixed two potential obscure race conditions in folder/Maildir.py.
+    + Condition 1 involved the gettimeseq() function.  This function
+      accesses per-module variables but does not have a lock.  It may have
+      been possible for this to have been called in such a way that timeseq
+      was not properly updated.
+    + Condition 2 involved the call to gettimeseq().  Since the timeseq is
+      based on the system clock, we now use the time as reported inside
+      timeseq() rather than outside.  This way, we can be assured that the
+      same value is in use both places.
+  * Added debug code to savemessage in folder/Maildir.py to try to track
+    down a mysterious 0-length file bug.
+
+ -- John Goerzen <[email protected]>  Tue,  6 May 2003 07:25:38 -0500
+
 offlineimap (3.99.16) unstable; urgency=low
 
   * This is a 4.0 TRACK release, and may be unstable or in flux!

Modified: offlineimap/head/offlineimap/folder/Maildir.py
==============================================================================
--- offlineimap/head/offlineimap/folder/Maildir.py	(original)
+++ offlineimap/head/offlineimap/folder/Maildir.py	2003-05-06 09:26:18.000000000 -0500
@@ -18,6 +18,8 @@
 
 from Base import BaseFolder
 from offlineimap import imaputil
+from offlineimap.ui import UIBase
+from threading import Lock
 import os.path, os, re, time, socket, md5
 
 foldermatchre = re.compile(',FMD5=([0-9a-f]{32})')
@@ -26,17 +28,22 @@
 
 timeseq = 0
 lasttime = long(0)
+timelock = Lock()
 
 def gettimeseq():
-    global lasttime, timeseq
-    thistime = long(time.time())
-    if thistime == lasttime:
-        timeseq += 1
-        return timeseq
-    else:
-        lasttime = long(time.time())
-        timeseq = 0
-        return timeseq
+    global lasttime, timeseq, timelock
+    timelock.acquire()
+    try:
+        thistime = long(time.time())
+        if thistime == lasttime:
+            timeseq += 1
+            return (thistime, timeseq)
+        else:
+            lasttime = thistime
+            timeseq = 0
+            return (thistime, timeseq)
+    finally:
+        timelock.release()
 
 class MaildirFolder(BaseFolder):
     def __init__(self, root, name, sep, repository, accountname):
@@ -118,6 +125,9 @@
         return retval.replace("\r\n", "\n")
 
     def savemessage(self, uid, content, flags):
+        ui = UIBase.getglobalui()
+        ui.debug('maildir', 'savemessage: called to write with flags %s and content %s' % \
+                 (repr(flags), repr(content)))
         if uid < 0:
             # We cannot assign a new uid.
             return uid
@@ -137,9 +147,10 @@
         while 1:
             if attempts > 15:
                 raise IOError, "Couldn't write to file %s" % messagename
+            timeval, timeseq = gettimeseq()
             messagename = '%d_%d.%d.%s,U=%d,FMD5=%s' % \
-                          (long(time.time()),
-                           gettimeseq(),
+                          (timeval,
+                           timeseq,
                            os.getpid(),
                            socket.gethostname(),
                            uid,
@@ -150,15 +161,19 @@
             else:
                 break
         tmpmessagename = messagename.split(',')[0]
+        ui.debug('maildir', 'savemessage: using temporary name %s' % tmpmessagename)
         file = open(os.path.join(tmpdir, tmpmessagename), "wt")
         file.write(content)
         file.close()
+        ui.debug('maildir', 'savemessage: moving from %s to %s' % \
+                 (tmpmessagename, messagename))
         os.link(os.path.join(tmpdir, tmpmessagename),
                 os.path.join(newdir, messagename))
         os.unlink(os.path.join(tmpdir, tmpmessagename))
         self.messagelist[uid] = {'uid': uid, 'flags': [],
                                  'filename': os.path.join(newdir, messagename)}
         self.savemessageflags(uid, flags)
+        ui.debug('maildir', 'savemessage: returning uid %d' % uid)
         return uid
         
     def getmessageflags(self, uid):