Multiple threads for different projects at the same time

[mauricioaniche]

Currently, thread implementation only works for a single project, i.e., one project needs to be entirely finished for the second one to start. We can then parallelize projects as well.

See this commit to understand more about how difficult this can be:
8d4bdd5

[davisjam]

I think this idea would make it harder to program against RepoDriller.

At the moment, the user's CommitVisitor(s) must be thread-safe (in case of RepositoryMining.withThreads).

If we begin handling projects in parallel, a CommitVisitor must track state associated with multiple projects at once. This is not really desirable, and I think we might then want to associate each CommitVisitor instance with a single repository.

I think #64 might be a better route. Turning up the parallelism on 1 repository or doing parallel work on N repositories should take roughly the same total time (and overall storage cost at any time), but I think writing a thread-safe CommitVisitor is more user-friendly than a multi-SCMRepository-safe CommitVisitor.

[davisjam]

Suggest we close this with #98

[mauricioaniche]

Agreed