git/builtin/diff-index.c
Junio C Hamano 1eb4136ac2 diff: --{rotate,skip}-to=<path>
In the implementation of "git difftool", there is a case where the
user wants to start viewing the diffs at a specific path and
continue on to the rest, optionally wrapping around to the
beginning.  Since it is somewhat cumbersome to implement such a
feature as a post-processing step of "git diff" output, let's
support it internally with two new options.

 - "git diff --rotate-to=C", when the resulting patch would show
   paths A B C D E without the option, would "rotate" the paths to
   shows patch to C D E A B instead.  It is an error when there is
   no patch for C is shown.

 - "git diff --skip-to=C" would instead "skip" the paths before C,
   and shows patch to C D E.  Again, it is an error when there is no
   patch for C is shown.

 - "git log [-p]" also accepts these two options, but it is not an
   error if there is no change to the specified path.  Instead, the
   set of output paths are rotated or skipped to the specified path
   or the first path that sorts after the specified path.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-16 09:30:42 -08:00

67 lines
1.7 KiB
C

#define USE_THE_INDEX_COMPATIBILITY_MACROS
#include "cache.h"
#include "config.h"
#include "diff.h"
#include "commit.h"
#include "revision.h"
#include "builtin.h"
#include "submodule.h"
static const char diff_cache_usage[] =
"git diff-index [-m] [--cached] "
"[<common-diff-options>] <tree-ish> [<path>...]"
COMMON_DIFF_OPTIONS_HELP;
int cmd_diff_index(int argc, const char **argv, const char *prefix)
{
struct rev_info rev;
unsigned int option = 0;
int i;
int result;
if (argc == 2 && !strcmp(argv[1], "-h"))
usage(diff_cache_usage);
git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
repo_init_revisions(the_repository, &rev, prefix);
rev.abbrev = 0;
precompose_argv(argc, argv);
argc = setup_revisions(argc, argv, &rev, NULL);
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
if (!strcmp(arg, "--cached"))
option |= DIFF_INDEX_CACHED;
else if (!strcmp(arg, "--merge-base"))
option |= DIFF_INDEX_MERGE_BASE;
else
usage(diff_cache_usage);
}
if (!rev.diffopt.output_format)
rev.diffopt.output_format = DIFF_FORMAT_RAW;
rev.diffopt.rotate_to_strict = 1;
/*
* Make sure there is one revision (i.e. pending object),
* and there is no revision filtering parameters.
*/
if (rev.pending.nr != 1 ||
rev.max_count != -1 || rev.min_age != -1 || rev.max_age != -1)
usage(diff_cache_usage);
if (!(option & DIFF_INDEX_CACHED)) {
setup_work_tree();
if (read_cache_preload(&rev.diffopt.pathspec) < 0) {
perror("read_cache_preload");
return -1;
}
} else if (read_cache() < 0) {
perror("read_cache");
return -1;
}
result = run_diff_index(&rev, option);
UNLEAK(rev);
return diff_result_code(&rev.diffopt, result);
}