magnet links download code is broken in latest version

[aldenml]

@aldenml
Hi. Everything is great except for one thing: my magnet links download code is broken:

java.lang.RuntimeException: invalid torrent handle used [libtorrent:20]
	at org.libtorrent4j.swig.libtorrent_jni.torrent_handle_resume(Native Method)
	at org.libtorrent4j.swig.torrent_handle.resume(torrent_handle.java:180)
	at org.proninyaroslav.libretorrent.core.model.session.TorrentSessionImpl.fetchMagnet(TorrentSessionImpl.java:477)
	... 12 more

Code:
https://github.com/proninyaroslav/libretorrent/blob/35bffbf874c0c4553f3ca751a0e3d76cb5c91c81/app/src/main/java/org/proninyaroslav/libretorrent/core/model/session/TorrentSessionImpl.java#L477

Overall, adding works if I remove resume(), but I get a perpetual progress bar in the preview dialog because I don't get the SAVE_RESUME_DATA alert.

Originally posted by @proninyaroslav in #290 (comment)

[proninyaroslav]

Is there an ETA for when this might be fixed? I was planning to release before August 31st when the next API bump is expected on Google Play.

[aldenml]

Hopefully I can find some time soon (before August 31).

[aldenml]

Hi @proninyaroslav, I was able to locate a couple of issues and test it.

1- In TorrentSessionImpl, it's necessary to invoke setSave_path like this

.....
if (TextUtils.isEmpty(p.getName()))
    p.setName(strHash);

p.setSave_path(File.createTempFile("libretorrent-magnets", "something").getAbsolutePath());

torrent_flags_t flags = p.getFlags();
flags = flags.and_(TorrentFlags.AUTO_MANAGED.inv());
.....

maybe you want to inject an application wide temp folder.

2- In TorrentMetaInfo, the constructor that receive byte[], the input needs to be copied to the byte buffer.

....
 var buffer = ByteBuffer.allocateDirect(data.length);
buffer.mark();
buffer.put(data);
buffer.reset();
long ptr = libtorrent_jni.directBufferAddress(buffer);
long size = libtorrent_jni.directBufferCapacity(buffer);
....

NOTE: this will not be necessary in the next release, I will expose the methods to work directly with the byte[].

Let me know how it goes :)

[proninyaroslav]

2- In TorrentMetaInfo, the constructor that receive byte[], the input needs to be copied to the byte buffer.

Yes, it was already done when the dependency was updated, apparently I forgot the saving itself :) :
https://github.com/proninyaroslav/libretorrent/blob/4323c5442a12363becc89f03617971bb9dfad93a/app/src/main/java/org/proninyaroslav/libretorrent/core/model/data/metainfo/TorrentMetaInfo.java#L66

[proninyaroslav]

1- In TorrentSessionImpl, it's necessary to invoke setSave_path like this

Works fine, thank you!