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git/notes-merge.c
Johan Herland 75ef3f4a5c git notes merge: Initial implementation handling trivial merges only
This initial implementation of 'git notes merge' only handles the trivial
merge cases (i.e. where the merge is either a no-op, or a fast-forward).

The patch includes testcases for these trivial merge cases.

Future patches will extend the functionality of 'git notes merge'.

This patch has been improved by the following contributions:
- Stephen Boyd: Simplify argc logic
- Stephen Boyd: Use test_commit
- Ævar Arnfjörð Bjarmason: Don't use C99 comments.
- Jonathan Nieder: Add constants for common verbosity values
- Jonathan Nieder: Use trace_printf(...) instead of OUTPUT(o, 5, ...)
- Jonathan Nieder: Remove extraneous show() function
- Jonathan Nieder: Clarify handling of empty/missing notes ref in notes_merge()
- Junio C Hamano: fixup minor style issues

Thanks-to: Stephen Boyd <bebarino@gmail.com>
Thanks-to: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Thanks-to: Jonathan Nieder <jrnieder@gmail.com>
Thanks-to: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-11-17 13:21:30 -08:00

121 lines
3.6 KiB
C

#include "cache.h"
#include "commit.h"
#include "refs.h"
#include "notes-merge.h"
void init_notes_merge_options(struct notes_merge_options *o)
{
memset(o, 0, sizeof(struct notes_merge_options));
o->verbosity = NOTES_MERGE_VERBOSITY_DEFAULT;
}
#define OUTPUT(o, v, ...) \
do { \
if ((o)->verbosity >= (v)) { \
printf(__VA_ARGS__); \
puts(""); \
} \
} while (0)
int notes_merge(struct notes_merge_options *o,
unsigned char *result_sha1)
{
unsigned char local_sha1[20], remote_sha1[20];
struct commit *local, *remote;
struct commit_list *bases = NULL;
const unsigned char *base_sha1;
int result = 0;
assert(o->local_ref && o->remote_ref);
hashclr(result_sha1);
trace_printf("notes_merge(o->local_ref = %s, o->remote_ref = %s)\n",
o->local_ref, o->remote_ref);
/* Dereference o->local_ref into local_sha1 */
if (!resolve_ref(o->local_ref, local_sha1, 0, NULL))
die("Failed to resolve local notes ref '%s'", o->local_ref);
else if (!check_ref_format(o->local_ref) && is_null_sha1(local_sha1))
local = NULL; /* local_sha1 == null_sha1 indicates unborn ref */
else if (!(local = lookup_commit_reference(local_sha1)))
die("Could not parse local commit %s (%s)",
sha1_to_hex(local_sha1), o->local_ref);
trace_printf("\tlocal commit: %.7s\n", sha1_to_hex(local_sha1));
/* Dereference o->remote_ref into remote_sha1 */
if (get_sha1(o->remote_ref, remote_sha1)) {
/*
* Failed to get remote_sha1. If o->remote_ref looks like an
* unborn ref, perform the merge using an empty notes tree.
*/
if (!check_ref_format(o->remote_ref)) {
hashclr(remote_sha1);
remote = NULL;
} else {
die("Failed to resolve remote notes ref '%s'",
o->remote_ref);
}
} else if (!(remote = lookup_commit_reference(remote_sha1))) {
die("Could not parse remote commit %s (%s)",
sha1_to_hex(remote_sha1), o->remote_ref);
}
trace_printf("\tremote commit: %.7s\n", sha1_to_hex(remote_sha1));
if (!local && !remote)
die("Cannot merge empty notes ref (%s) into empty notes ref "
"(%s)", o->remote_ref, o->local_ref);
if (!local) {
/* result == remote commit */
hashcpy(result_sha1, remote_sha1);
goto found_result;
}
if (!remote) {
/* result == local commit */
hashcpy(result_sha1, local_sha1);
goto found_result;
}
assert(local && remote);
/* Find merge bases */
bases = get_merge_bases(local, remote, 1);
if (!bases) {
base_sha1 = null_sha1;
OUTPUT(o, 4, "No merge base found; doing history-less merge");
} else if (!bases->next) {
base_sha1 = bases->item->object.sha1;
OUTPUT(o, 4, "One merge base found (%.7s)",
sha1_to_hex(base_sha1));
} else {
/* TODO: How to handle multiple merge-bases? */
base_sha1 = bases->item->object.sha1;
OUTPUT(o, 3, "Multiple merge bases found. Using the first "
"(%.7s)", sha1_to_hex(base_sha1));
}
OUTPUT(o, 4, "Merging remote commit %.7s into local commit %.7s with "
"merge-base %.7s", sha1_to_hex(remote->object.sha1),
sha1_to_hex(local->object.sha1), sha1_to_hex(base_sha1));
if (!hashcmp(remote->object.sha1, base_sha1)) {
/* Already merged; result == local commit */
OUTPUT(o, 2, "Already up-to-date!");
hashcpy(result_sha1, local->object.sha1);
goto found_result;
}
if (!hashcmp(local->object.sha1, base_sha1)) {
/* Fast-forward; result == remote commit */
OUTPUT(o, 2, "Fast-forward");
hashcpy(result_sha1, remote->object.sha1);
goto found_result;
}
/* TODO: */
result = error("notes_merge() cannot yet handle real merges.");
found_result:
free_commit_list(bases);
trace_printf("notes_merge(): result = %i, result_sha1 = %.7s\n",
result, sha1_to_hex(result_sha1));
return result;
}