[Libtorrent-devel] how to open and start a download in source code

[Jari Sundell]

Nemo wrote:
> i want get "auto open/close torrent" function via modify libtorrent  
> source code.
> 
> i can auto stop a torrent now, when erase a peer ( in 
> ConnectionList::iterator ConnectionList::erase(iterator pos, int flags) 
> ) , check size of connectionlist, close (Download::stop() and 
> Download::close()) torrent when size is 0.
> 
> libtorent will throw a handshake error when libtorrent get a request of 
> handshake and the torrent  requested is not active in original source 
> code, i modify code here hope open the torrent complete handshake and 
> download instead of throw error.
> i got problem here, i can open a torrent via call  Download::open(), but 
> i got a "Tried to start an unchecked download" error if call 
> Download::start() directly and skip Download::hash_check(). i do not 
> know how to use hash_check() here, who can  give me some suggestion how 
> to open and start a download, i am a newbie and sorry for my poor english.

You need to ensure resume data is loaded to avoid rehashing the entire 
torrent, so you can't just call hash_check. In 
rtorrent/src/core/manager.cc:491 you see how the torrent gets hash checked.

However, doing this inside libtorrent isn't really recommended, as the 
client probably won't entirely like having these things happen 
out-of-order. I'd recommend adding signals to torrent::Download and call 
the proper commands through those.

Jari Sundell