This patch linearises the GIT commit history graph into merge order
which is defined by invariants specified in Documentation/git-rev-list.txt.
The linearisation produced by this patch is superior in an objective sense
to that produced by the existing git-rev-list implementation in that
the linearisation produced is guaranteed to have the minimum number of
discontinuities, where a discontinuity is defined as an adjacent pair of
commits in the output list which are not related in a direct child-parent
relationship.
With this patch a graph like this:
a4 ---
| \ \
| b4 |
|/ | |
a3 | |
| | |
a2 | |
| | c3
| | |
| | c2
| b3 |
| | /|
| b2 |
| | c1
| | /
| b1
a1 |
| |
a0 |
| /
root
Sorts like this:
= a4
| c3
| c2
| c1
^ b4
| b3
| b2
| b1
^ a3
| a2
| a1
| a0
= root
Instead of this:
= a4
| c3
^ b4
| a3
^ c2
^ b3
^ a2
^ b2
^ c1
^ a1
^ b1
^ a0
= root
A test script, t/t6000-rev-list.sh, includes a test which demonstrates
that the linearisation produced by --merge-order has less discontinuities
than the linearisation produced by git-rev-list without the --merge-order
flag specified. To see this, do the following:
cd t
./t6000-rev-list.sh
cd trash
cat actual-default-order
cat actual-merge-order
The existing behaviour of git-rev-list is preserved, by default. To obtain
the modified behaviour, specify --merge-order or --merge-order --show-breaks
on the command line.
This version of the patch has been tested on the git repository and also on the linux-2.6
repository and has reasonable performance on both - ~50-100% slower than the original algorithm.
This version of the patch has incorporated a functional equivalent of the Linus' output limiting
algorithm into the merge-order algorithm itself. This operates per the notes associated
with Linus' commit 337cb3fb8d.
This version has incorporated Linus' feedback regarding proposed changes to rev-list.c.
(see: [PATCH] Factor out filtering in rev-list.c)
This version has improved the way sort_first_epoch marks commits as uninteresting.
For more details about this change, refer to Documentation/git-rev-list.txt
and http://blackcubes.dyndns.org/epoch/.
Signed-off-by: Jon Seymour <jon.seymour@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
You can ask to print out "raw" format (full headers, full body),
"medium" format (author and date, full body) or "short" format
(author only, condensed body).
Use "git-rev-list --pretty=short HEAD | less -S" for an example.
object.
A fair number of the users potentially want to look at the
commit objects more closely, and if you worry about memory
leaking in certain applications, you can always do a
free(commit->buffer);
commit->buffer = NULL;
by hand after parsing them.
It turns out that parse_object() is loading and decompressing given
object to free it just before calling the specific object parsing
function which does mmap and decompress the same object again. This
patch introduces the ability to parse specific objects directly from a
memory buffer.
Without this patch, running git-fsck-cache on the kernel repositorytake:
real 0m13.006s
user 0m11.421s
sys 0m1.218s
With this patch applied:
real 0m8.060s
user 0m7.071s
sys 0m0.710s
The performance increase is significant, and this is kind of a
prerequisite for sane delta object support with fsck.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make pop_most_recent_commit() return the same objects multiple times, but only
if called with different bits to mark.
This is necessary to make merge-base work again.
Signed-Off-By: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This adds a function for inserting an item in a commit list, a function
for sorting a commit list by date, and a function for progressively
scanning a commit history from most recent to least recent.
Signed-Off-By: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This adds the structs and function declarations for parsing git objects.
Signed-Off-By: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
