YAM delete old entries in the .uidl file

I will try to reproduce this myself later. I had the same problem several times by now. And having to download 100+ mails again because of a broken download before is a real PITA with a crawling connection. Unfortunately I wasn't able to take a deeper look at this before, because every time I tried to enforce this issue it simply did not happen and YAM just downloaded the remaining mails.

I don't look at the sources but IMHO we need a better save routine
which doesn't destroy such important file. E.g. save the Data
to a temporary file and only if it was sucessful then delete to original
file and rename the temporary file to the original filename.
Maybe with a additional security check if the new file size is at least
equal (or bigger) as the original file size.

Since some versions my .uidl file has the size 0 after getting mails.
I have more as one account at yahoo. One is set up to don't delete the
mails on the server. From this server are the .uidl entries.

After i get mails form one of the other yahoo accounts my .uidl file
is always empty. uidl log:

00:D:      YAM_TR.c:693:added UIDL 'ALexktkAAFaVS4YUbg3DsEQ5GPc@pop.mail.yahoo.com' (0b77de58) to hash
00:D:      YAM_TR.c:693:added UIDL 'ALKxktkAAEitS4nzEQZgezcYDl8@pop.mail.yahoo.com' (0b77de62) to hash

... a lot of entries

00:D:      YAM_TR.c:693:added UIDL 'ALGxktkAAKUfS9iA/gWqVDDnI7s@pop.mail.yahoo.com' (0b77f23a) to hash
00:D:      YAM_TR.c:693:added UIDL 'ALWxktkAAJg5S/Fs5A3dvCq9Z6w@pop.mail.yahoo.com' (0b77e6f0) to hash
00:C:     YAM_TR.c:565:G->TR->UIDLhashTable->entryCount = 376, 0x00000178
00:W:      Timer.c:167:timer[6]: already stopped
00:D:      YAM_TR.c:712:removed UIDL 'AFty+FcAAQX5TH1+PAyJlXJfwGs@pop.mail.yahoo.com' from hash
00:D:       MainWindowToolbar.c:287:case 6
00:D:         YAM_TR.c:631:orphaned UIDL found and deleted 'ALexktkAAFaVS4YUbg3DsEQ5GPc@pop.mail.yahoo.com'
00:D:         YAM_TR.c:631:orphaned UIDL found and deleted 'ALKxktkAAEitS4nzEQZgezcYDl8@pop.mail.yahoo.com'

... a lot of entries (same as deleted above)

00:D:         YAM_TR.c:631:orphaned UIDL found and deleted 'ALGxktkAAKUfS9iA/gWqVDDnI7s@pop.mail.yahoo.com'
00:D:         YAM_TR.c:631:orphaned UIDL found and deleted 'ALSxktkAANJSS+sNPwoDJxWgnEI@pop.mail.yahoo.com'
00:D:       YAM_TR.c:669:successfully cleaned up UIDLhash

So the bug seems to be in the SaveUIDLtoken() function.
Seems the check for the server dosn't work like expected
or at least like before the latest changes.

(In [5132]) * YAM_TR.c, tcp/pop3.c: reworked the UIDL management. First of all YAM will

use separate files for each account to avoid any mix up of (in)active and/or
(un)checked accounts. The filename will be built as ".uidl_<user>_<host>"
to be unique even for multiple accounts with the same host. The old .uidl
file will be kept as a fallback, because it may contain UIDLs of multiple
accounts. The new .uidl_* file will be written only if new entries added
added to the database. This also means that old and outdated entries will
vanish only if there are new mails to be remembered. Mails will be rem-
embered as soon as they were downloaded or just deleted. This respects the
fact that certain providers don't delete mails immediately but only after a
proper QUIT command. The result of an aborted download was that already
deleted mails were downloaded again, even if YAM was configured to avoid
duplicate mails. All this closes #191. The old style .uidl must deleted
manually if the user is sure that all contained UIDLs really don't longer
reside on the server.