Fixes races conditions and make the DB Switchable. Also prepare inside
the CompilationSpec the tree of the deps to be built, and parallelize
only the building jobs.
Closes#7
Signed-off-by: Ettore Di Giacinto <mudler@gentoo.org>
Add CompilationSpecs type to handle slices of CompilationSpec, to
perform operation such as Unique() and Remove().
Add also dependencies and the spec associated to the Artifact, to track
how the artifact was generated.
Add revdeps compilation wrapper, and unit tests
Uninstall can be done in different ways - the most accurate would be to try find a minimum subset of packages that gives conflicts and try to reduce them gradually.
E.g. this could be done with other SAT algorithms. For now we keep things simple and we compute the uninstalls as an indirect of an installation from an empty profile.
Also take care of corner cases where world has no clauses, and fixes a typo in building the world formula
