Since gnulib-tool does not modify modules, it is OK to initialize each
module only once. Moreover, since most of the time is spent upon
executing transitive closures and each transitive closure stores all
modules into different lists, it is also a good idea to calculate the
hash only once for read-only modules. These simple additions make
gnulib-tool much faster than before, since each module is initialized
only once-per-run and has a constant hash value.
For example, an invocation of pygnulib.py inside wget2 takes about 0.5
seconds until it completes gnulib-comp.m4 generation; previously it used
to take up to 8 seconds. Needless to say that performing the same task
is much slower when using the good old gnulib-tool: in my experiments
it takes about a minute to complete gnulib-comp.m4 generation.
Some of the TransitiveClosure methods considered useful enough to be
also present as a part of Database class. The refactoring also revealed
that conditional modules computation was implemented incorrectly; this
code was fixed. Moreover, this part of functionality was moved into the
__init__ section, which also saves several milliseconds since it is not
necessary to check whether conditional modules table exists upon each
conditional() invocation.
In order to implement correct gnulib-comp.m4 generation, the whole
conditional dependencies calculation algorithm had to be rewritten.
This patch fixes transitive closure algorithm so that it handles all
conditions correctly. Most of the transitive closure functionality was
separated into a standalone TransitiveClosure class to provide a fast
access to transitive closure results (thus incorporating almost all
functionality of the pygnulib.module.Database class).
The transitive closure is usually performed twice: the base one checks
dependencies for the base set of modules, while the full one also takes
the corresponding tests into account. A standalone Database class was
created to perform both closures in one shot and provide an easy access
to all required module and file lists. This allowed to incorporate some
code from the main script: dummy module handling, libtests.a presense,
module and file lists processing.
Yet another small change is that there is a special DummyModule object,
representing the well-known gnulib dummy module. It was created since
the original gnulib dummy module is unlikely to change quite often, so
it acts like special placeholder value.
Finally the naming convention was changed to longer names again.
Dmitry Selyutin