We already keep this dictionary in our repository. Rather than adding a
pointer to it on every commit in our rev walk, just look it up lazily in the
dictionary when we need to. That cuts down some time in the initial revwalk
and also removes some stupid code :)
We used to output a line for every lane after the
lane in which the current commit is in, and also
make it have the wrong color. This fixes the buglet
and also makes sure not to draw a line when
the commit has no parents.
This was somewhat unfortunate, as we don't check
on if we have at least a single parent when adding
new parents. That would cause a wild pointer, or null
dereference when creating a new lane.
This uses a normal c array to store parent sha's. That means that we
save a lot of room, as they are only 20 bytes rather than 40 + the cost of
an NSArray and the NSStrings.
We used to use NSObjects, which was really expensive, because for each commit
as many as 100 graphlines can be created. By preallocating them and not
using NSObjects in general, we gain a massive speedup
I'm not sure what this loop originally did, but it was buggy and doesn't
seem logical. Removing it speeds up the graphing a lot, so let's kill it.
We can always get it back later if necessary
Yoshimasa Niwa