--- AttachFile_from_cvs.py	Thu Feb 13 18:27:50 2003
+++ AttachFile.py	Thu Feb 13 18:38:48 2003
@@ -24,7 +24,7 @@
     $Id: AttachFile.py,v 1.48 2003/02/12 23:33:40 jhermann Exp $
 """
 
-import cgi, os, mimetypes, string, sys, time, urllib
+import cgi, os, mimetypes, string, sys, time, urllib, re
 from MoinMoin import config, user, util, wikiutil, webapi
 from MoinMoin.Page import Page
 from MoinMoin.util import filesys
@@ -134,6 +134,25 @@
     error_msg(pagename, request, error)
     return (None, None)
 
+def _backup_file(fpath):
+    """Move the file `fpath` to `fpath,nnn` where `nnn` is one plus `mmm`, where
+       `mmm` is the highest number for which `fpath.mmm` exists, or 000 if no
+       such file exists."""
+    
+    # find the right sequence number
+    dirname, basename = os.path.split(fpath)
+    backup_re = re.compile(r'^%s\,(?P<seq>\d\d\d)$' % basename)
+    backups = filter(backup_re.match, os.listdir(dirname))
+    backups.sort()
+    if backups == []:
+        seq_no = 0
+    else:
+        highest = backups[-1]
+        seq_no = int(backup_re.match(highest).group('seq')) + 1
+        
+    # do the move
+    new_name = "%s,%03d" % (fpath, seq_no)
+    os.rename(fpath, new_name)
 
 def _get_filelist(request, pagename):
     _ = request.getText
@@ -145,6 +164,10 @@
         files = os.listdir(attach_dir)
         files.sort()
 
+    # filter out backup files
+    backup_re = re.compile(r'.*\,\d\d\d$')
+    files = filter(lambda x: not backup_re.match(x), files)
+
     str = ""
     if files:
         str = str + _("<p>"
@@ -260,9 +283,9 @@
 
     print _("""
 <h2>New Attachment</h2>
-<p>An upload will never overwrite an existing file. If there is a name
-conflict, you have to rename the file that you want to upload.
-Otherwise, if "Rename to" is left blank, the original filename will be used.</p>
+<p>When uploading under a filename for which an attachment already exists,
+the old version is stored - ask the administrator to recover it.</p>
+<p>If "Rename to" is left blank, the original filename will be used.</p>
 """)
     print """
 <form action="%(baseurl)s/%(pagename)s" method="POST" enctype="multipart/form-data">
@@ -383,20 +406,20 @@
     # save file
     fpath = os.path.join(attach_dir, target)
     if os.path.exists(fpath):
-        msg = _("Attachment '%(target)s' (remote name '%(filename)s') already exists.") % locals()
-    else:
-        content = fileitem.file.read()
-        stream = open(fpath, 'wb')
-        try:
-            stream.write(content)
-        finally:
-            stream.close()
-        os.chmod(fpath, 0666 & config.umask)
-
-        bytes = len(content)
-        msg = _("Attachment '%(target)s' (remote name '%(filename)s')"
-                " with %(bytes)d bytes saved.") % locals()
-        _addLogEntry(request, 'ATTNEW', pagename, target)
+        _backup_file(fpath)
+
+    content = fileitem.file.read()
+    stream = open(fpath, 'wb')
+    try:
+        stream.write(content)
+    finally:
+        stream.close()
+    os.chmod(fpath, 0666 & config.umask)
+
+    bytes = len(content)
+    msg = _("Attachment '%(target)s' (remote name '%(filename)s')"
+            " with %(bytes)d bytes saved.") % locals()
+    _addLogEntry(request, 'ATTNEW', pagename, target)
 
     # return attachment list
     upload_form(pagename, request, msg)
@@ -433,6 +456,8 @@
         _addLogEntry(request, 'ATTDRW', pagename, basename + ext)
 
     savepath = os.path.join(getAttachDir(pagename), basename + ext)
+    if os.path.exists(savepath):
+        _backup_file(savepath)
     file = open(savepath, 'wb')
     try:
         file.write(content)
@@ -448,7 +473,9 @@
     if not filename: return # error msg already sent in _access_file
     
     # delete file
-    os.remove(fpath)
+    if os.path.exists(fpath):
+        _backup_file(fpath)
+
     _addLogEntry(request, 'ATTDEL', pagename, filename)
 
     upload_form(pagename, request, msg=_("Attachment '%(filename)s' deleted.") % locals())