We've had this notion of a "object_list" for a long time, which eventually
grew a "name" member because some users (notably git-rev-list) wanted to
name each object as it is generated.
That object_list is great for some things, but it isn't all that wonderful
for others, and the "name" member is generally not used by everybody.
This patch splits the users of the object_list array up into two: the
traditional list users, who want the list-like format, and who don't
actually use or want the name. And another class of users that really used
the list as an extensible array, and generally wanted to name the objects.
The patch is fairly straightforward, but it's also biggish. Most of it
really just cleans things up: switching the revision parsing and listing
over to the array makes things like the builtin-diff usage much simpler
(we now see exactly how many members the array has, and we don't get the
objects reversed from the order they were on the command line).
One of the main reasons for doing this at all is that the malloc overhead
of the simple object list was actually pretty high, and the array is just
a lot denser. So this patch brings down memory usage by git-rev-list by
just under 3% (on top of all the other memory use optimizations) on the
mozilla archive.
It does add more lines than it removes, and more importantly, it adds a
whole new infrastructure for maintaining lists of objects, but on the
other hand, the new dynamic array code is pretty obvious. The change to
builtin-diff-tree.c shows a fairly good example of why an array interface
is sometimes more natural, and just much simpler for everybody.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
There are times when gitk needs to know that the commits it has sent
to git-diff-tree --stdin did not match, and it needs to know in a
timely fashion even if none of them match. At the moment,
git-diff-tree outputs nothing for non-matching commits, so it is
impossible for gitk to distinguish between git-diff-tree being slow
and git-diff-tree saying no.
This makes git-diff-tree flush its output and echo back the
input line when it is not a valid-looking object name. Gitk, or
other users of git-diff-tree --stdin, can use a blank line or
any other "marker line" to indicate that git-diff-tree has
processed all the commits on its input up to the echoed back
marker line, and any commits that have not been output do not
match.
[jc: re-done after a couple of back-and-forth discussion on the list.]
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
