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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>
57 lines
1.3 KiB
C
57 lines
1.3 KiB
C
#ifndef COMMIT_H
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#define COMMIT_H
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#include "object.h"
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#include "tree.h"
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struct commit_list {
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struct commit *item;
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struct commit_list *next;
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};
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struct commit {
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struct object object;
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unsigned long date;
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struct commit_list *parents;
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struct tree *tree;
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char *buffer;
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};
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extern const char *commit_type;
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struct commit *lookup_commit(unsigned char *sha1);
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struct commit *lookup_commit_reference(unsigned char *sha1);
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int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size);
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int parse_commit(struct commit *item);
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struct commit_list * commit_list_insert(struct commit *item, struct commit_list **list_p);
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void free_commit_list(struct commit_list *list);
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void sort_by_date(struct commit_list **list);
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/* Commit formats */
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enum cmit_fmt {
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CMIT_FMT_RAW,
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CMIT_FMT_MEDIUM,
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CMIT_FMT_DEFAULT = CMIT_FMT_MEDIUM,
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CMIT_FMT_SHORT
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};
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extern unsigned long pretty_print_commit(enum cmit_fmt fmt, const char *msg, unsigned long len, char *buf, unsigned long space);
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void insert_by_date(struct commit_list **list, struct commit *item);
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/** Removes the first commit from a list sorted by date, and adds all
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* of its parents.
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**/
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struct commit *pop_most_recent_commit(struct commit_list **list,
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unsigned int mark);
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struct commit *pop_commit(struct commit_list **stack);
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int count_parents(struct commit * commit);
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#endif /* COMMIT_H */
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