git/builtin/diff-files.c
Shuqi Liang 8c30be9176 diff-files: integrate with sparse index
Remove full index requirement for `git diff-files`. Refactor the
ensure_expanded and ensure_not_expanded functions by introducing a
common helper function, ensure_index_state. Add test to ensure the index
is no expanded in `git diff-files`.

The `p2000` tests demonstrate a ~96% execution time reduction for 'git
diff-files' and a ~97% execution time reduction for 'git diff-files'
for a file using a sparse index:

Test                                               before  after
-----------------------------------------------------------------------
2000.94: git diff-files (full-v3)                  0.09    0.08 -11.1%
2000.95: git diff-files (full-v4)                  0.09    0.09 +0.0%
2000.96: git diff-files (sparse-v3)                0.52    0.02 -96.2%
2000.97: git diff-files (sparse-v4)                0.51    0.02 -96.1%
2000.98: git diff-files -- f2/f4/a (full-v3)       0.06    0.07 +16.7%
2000.99: git diff-files -- f2/f4/a (full-v4)       0.08    0.08 +0.0%
2000.100: git diff-files -- f2/f4/a (sparse-v3)    0.46    0.01 -97.8%
2000.101: git diff-files -- f2/f4/a (sparse-v4)    0.51    0.02 -96.1%

Signed-off-by: Shuqi Liang <cheskaqiqi@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-05-09 14:26:36 -07:00

92 lines
2.5 KiB
C

/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*/
#include "cache.h"
#include "config.h"
#include "diff.h"
#include "diff-merges.h"
#include "commit.h"
#include "revision.h"
#include "builtin.h"
#include "submodule.h"
static const char diff_files_usage[] =
"git diff-files [-q] [-0 | -1 | -2 | -3 | -c | --cc] [<common-diff-options>] [<path>...]"
"\n"
COMMON_DIFF_OPTIONS_HELP;
int cmd_diff_files(int argc, const char **argv, const char *prefix)
{
struct rev_info rev;
int result;
unsigned options = 0;
if (argc == 2 && !strcmp(argv[1], "-h"))
usage(diff_files_usage);
git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
prepare_repo_settings(the_repository);
the_repository->settings.command_requires_full_index = 0;
repo_init_revisions(the_repository, &rev, prefix);
rev.abbrev = 0;
/*
* Consider "intent-to-add" files as new by default, unless
* explicitly specified in the command line or anywhere else.
*/
rev.diffopt.ita_invisible_in_index = 1;
prefix = precompose_argv_prefix(argc, argv, prefix);
argc = setup_revisions(argc, argv, &rev, NULL);
while (1 < argc && argv[1][0] == '-') {
if (!strcmp(argv[1], "--base"))
rev.max_count = 1;
else if (!strcmp(argv[1], "--ours"))
rev.max_count = 2;
else if (!strcmp(argv[1], "--theirs"))
rev.max_count = 3;
else if (!strcmp(argv[1], "-q"))
options |= DIFF_SILENT_ON_REMOVED;
else
usage(diff_files_usage);
argv++; argc--;
}
if (!rev.diffopt.output_format)
rev.diffopt.output_format = DIFF_FORMAT_RAW;
rev.diffopt.rotate_to_strict = 1;
/*
* Make sure there are NO revision (i.e. pending object) parameter,
* rev.max_count is reasonable (0 <= n <= 3), and
* there is no other revision filtering parameters.
*/
if (rev.pending.nr ||
rev.min_age != -1 || rev.max_age != -1 ||
3 < rev.max_count)
usage(diff_files_usage);
/*
* "diff-files --base -p" should not combine merges because it
* was not asked to. "diff-files -c -p" should not densify
* (the user should ask with "diff-files --cc" explicitly).
*/
if (rev.max_count == -1 &&
(rev.diffopt.output_format & DIFF_FORMAT_PATCH))
diff_merges_set_dense_combined_if_unset(&rev);
if (repo_read_index_preload(the_repository, &rev.diffopt.pathspec, 0) < 0) {
perror("repo_read_index_preload");
result = -1;
goto cleanup;
}
result = run_diff_files(&rev, options);
result = diff_result_code(&rev.diffopt, result);
cleanup:
release_revisions(&rev);
return result;
}