[sword-devel] Thread safety and other problems of installmgr

[Eeli Kaikkonen]

The installmgr with libcurl isn't thread safe. It has - as the whole mgr 
with any ftpmgr - another problem, too: it's not possible to cancel 
downloading at any time. The installmgr has terminate() but it only sets 
a flag which is checked after each file has been downloaded. It means 
that stalled or slow downloading can't really be cancelled.

Libcurl has "multi" interface which could enable threaded usage. Now the 
installmgr uses "easy" which is not meant for concurrent downloads.

If we want the installmgr to work with threads it should have a thread 
safe terminate() which calls ftpmgr's thread safe terminate() which 
calls underlying ftp library's thread-safe connection termination function.

Writing an ftpmgr implementation inside an app can solve this problem 
because it can be terminated directly from the app code.

--Eeli Kaikkonen