git/builtin/merge-file.c
Antonin Delpeuch 4f7fd79e57 merge-file: add --diff-algorithm option
Make it possible to use other diff algorithms than the 'myers'
default algorithm, when using the 'git merge-file' command, to help
avoid spurious conflicts by selecting a more recent algorithm such
as 'histogram', for instance when using 'git merge-file' as part of
a custom merge driver.

Signed-off-by: Antonin Delpeuch <antonin@delpeuch.eu>
Reviewed-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-11-22 14:23:06 +09:00

185 lines
4.9 KiB
C

#include "builtin.h"
#include "abspath.h"
#include "diff.h"
#include "hex.h"
#include "object-name.h"
#include "object-store.h"
#include "config.h"
#include "gettext.h"
#include "setup.h"
#include "xdiff/xdiff.h"
#include "xdiff-interface.h"
#include "parse-options.h"
static const char *const merge_file_usage[] = {
N_("git merge-file [<options>] [-L <name1> [-L <orig> [-L <name2>]]] <file1> <orig-file> <file2>"),
NULL
};
static int label_cb(const struct option *opt, const char *arg, int unset)
{
static int label_count = 0;
const char **names = (const char **)opt->value;
BUG_ON_OPT_NEG(unset);
if (label_count >= 3)
return error("too many labels on the command line");
names[label_count++] = arg;
return 0;
}
static int set_diff_algorithm(xpparam_t *xpp,
const char *alg)
{
long diff_algorithm = parse_algorithm_value(alg);
if (diff_algorithm < 0)
return -1;
xpp->flags = (xpp->flags & ~XDF_DIFF_ALGORITHM_MASK) | diff_algorithm;
return 0;
}
static int diff_algorithm_cb(const struct option *opt,
const char *arg, int unset)
{
xpparam_t *xpp = opt->value;
BUG_ON_OPT_NEG(unset);
if (set_diff_algorithm(xpp, arg))
return error(_("option diff-algorithm accepts \"myers\", "
"\"minimal\", \"patience\" and \"histogram\""));
return 0;
}
int cmd_merge_file(int argc, const char **argv, const char *prefix)
{
const char *names[3] = { 0 };
mmfile_t mmfs[3] = { 0 };
mmbuffer_t result = { 0 };
xmparam_t xmp = { 0 };
int ret = 0, i = 0, to_stdout = 0, object_id = 0;
int quiet = 0;
struct option options[] = {
OPT_BOOL('p', "stdout", &to_stdout, N_("send results to standard output")),
OPT_BOOL(0, "object-id", &object_id, N_("use object IDs instead of filenames")),
OPT_SET_INT(0, "diff3", &xmp.style, N_("use a diff3 based merge"), XDL_MERGE_DIFF3),
OPT_SET_INT(0, "zdiff3", &xmp.style, N_("use a zealous diff3 based merge"),
XDL_MERGE_ZEALOUS_DIFF3),
OPT_SET_INT(0, "ours", &xmp.favor, N_("for conflicts, use our version"),
XDL_MERGE_FAVOR_OURS),
OPT_SET_INT(0, "theirs", &xmp.favor, N_("for conflicts, use their version"),
XDL_MERGE_FAVOR_THEIRS),
OPT_SET_INT(0, "union", &xmp.favor, N_("for conflicts, use a union version"),
XDL_MERGE_FAVOR_UNION),
OPT_CALLBACK_F(0, "diff-algorithm", &xmp.xpp, N_("<algorithm>"),
N_("choose a diff algorithm"),
PARSE_OPT_NONEG, diff_algorithm_cb),
OPT_INTEGER(0, "marker-size", &xmp.marker_size,
N_("for conflicts, use this marker size")),
OPT__QUIET(&quiet, N_("do not warn about conflicts")),
OPT_CALLBACK('L', NULL, names, N_("name"),
N_("set labels for file1/orig-file/file2"), &label_cb),
OPT_END(),
};
xmp.level = XDL_MERGE_ZEALOUS_ALNUM;
xmp.style = 0;
xmp.favor = 0;
if (startup_info->have_repository) {
/* Read the configuration file */
git_config(git_xmerge_config, NULL);
if (0 <= git_xmerge_style)
xmp.style = git_xmerge_style;
}
argc = parse_options(argc, argv, prefix, options, merge_file_usage, 0);
if (argc != 3)
usage_with_options(merge_file_usage, options);
if (quiet) {
if (!freopen("/dev/null", "w", stderr))
return error_errno("failed to redirect stderr to /dev/null");
}
if (object_id)
setup_git_directory();
for (i = 0; i < 3; i++) {
char *fname;
struct object_id oid;
mmfile_t *mmf = mmfs + i;
if (!names[i])
names[i] = argv[i];
fname = prefix_filename(prefix, argv[i]);
if (object_id) {
if (repo_get_oid(the_repository, argv[i], &oid))
ret = error(_("object '%s' does not exist"),
argv[i]);
else if (!oideq(&oid, the_hash_algo->empty_blob))
read_mmblob(mmf, &oid);
else
read_mmfile(mmf, "/dev/null");
} else if (read_mmfile(mmf, fname)) {
ret = -1;
}
if (ret != -1 && (mmf->size > MAX_XDIFF_SIZE ||
buffer_is_binary(mmf->ptr, mmf->size))) {
ret = error("Cannot merge binary files: %s",
argv[i]);
}
free(fname);
if (ret)
goto cleanup;
}
xmp.ancestor = names[1];
xmp.file1 = names[0];
xmp.file2 = names[2];
ret = xdl_merge(mmfs + 1, mmfs + 0, mmfs + 2, &xmp, &result);
if (ret >= 0) {
if (object_id && !to_stdout) {
struct object_id oid;
if (result.size) {
if (write_object_file(result.ptr, result.size, OBJ_BLOB, &oid) < 0)
ret = error(_("Could not write object file"));
} else {
oidcpy(&oid, the_hash_algo->empty_blob);
}
if (ret >= 0)
printf("%s\n", oid_to_hex(&oid));
} else {
const char *filename = argv[0];
char *fpath = prefix_filename(prefix, argv[0]);
FILE *f = to_stdout ? stdout : fopen(fpath, "wb");
if (!f)
ret = error_errno("Could not open %s for writing",
filename);
else if (result.size &&
fwrite(result.ptr, result.size, 1, f) != 1)
ret = error_errno("Could not write to %s", filename);
else if (fclose(f))
ret = error_errno("Could not close %s", filename);
free(fpath);
}
free(result.ptr);
}
if (ret > 127)
ret = 127;
cleanup:
for (i = 0; i < 3; i++)
free(mmfs[i].ptr);
return ret;
}