path: root/notes-merge.c

#include "cache.h"
#include "commit.h"
#include "refs.h"
#include "diff.h"
#include "diffcore.h"
#include "xdiff-interface.h"
#include "ll-merge.h"
#include "dir.h"
#include "notes.h"
#include "notes-merge.h"
#include "strbuf.h"
#include "notes-utils.h"

struct notes_merge_pair {
	struct object_id obj, base, local, remote;
};

void init_notes_merge_options(struct notes_merge_options *o)
{
	memset(o, 0, sizeof(struct notes_merge_options));
	strbuf_init(&(o->commit_msg), 0);
	o->verbosity = NOTES_MERGE_VERBOSITY_DEFAULT;
}

static int path_to_oid(const char *path, struct object_id *oid)
{
	char hex_oid[GIT_SHA1_HEXSZ];
	int i = 0;
	while (*path && i < GIT_SHA1_HEXSZ) {
		if (*path != '/')
			hex_oid[i++] = *path;
		path++;
	}
	if (*path || i != GIT_SHA1_HEXSZ)
		return -1;
	return get_oid_hex(hex_oid, oid);
}

static int verify_notes_filepair(struct diff_filepair *p, struct object_id *oid)
{
	switch (p->status) {
	case DIFF_STATUS_MODIFIED:
		assert(p->one->mode == p->two->mode);
		assert(!is_null_oid(&p->one->oid));
		assert(!is_null_oid(&p->two->oid));
		break;
	case DIFF_STATUS_ADDED:
		assert(is_null_oid(&p->one->oid));
		break;
	case DIFF_STATUS_DELETED:
		assert(is_null_oid(&p->two->oid));
		break;
	default:
		return -1;
	}
	assert(!strcmp(p->one->path, p->two->path));
	return path_to_oid(p->one->path, oid);
}

static struct notes_merge_pair *find_notes_merge_pair_pos(
		struct notes_merge_pair *list, int len, struct object_id *obj,
		int insert_new, int *occupied)
{
	/*
	 * Both diff_tree_remote() and diff_tree_local() tend to process
	 * merge_pairs in ascending order. Therefore, cache last returned
	 * index, and search sequentially from there until the appropriate
	 * position is found.
	 *
	 * Since inserts only happen from diff_tree_remote() (which mainly
	 * _appends_), we don't care that inserting into the middle of the
	 * list is expensive (using memmove()).
	 */
	static int last_index;
	int i = last_index < len ? last_index : len - 1;
	int prev_cmp = 0, cmp = -1;
	while (i >= 0 && i < len) {
		cmp = oidcmp(obj, &list[i].obj);
		if (!cmp) /* obj belongs @ i */
			break;
		else if (cmp < 0 && prev_cmp <= 0) /* obj belongs < i */
			i--;
		else if (cmp < 0) /* obj belongs between i-1 and i */
			break;
		else if (cmp > 0 && prev_cmp >= 0) /* obj belongs > i */
			i++;
		else /* if (cmp > 0) */ { /* obj belongs between i and i+1 */
			i++;
			break;
		}
		prev_cmp = cmp;
	}
	if (i < 0)
		i = 0;
	/* obj belongs at, or immediately preceding, index i (0 <= i <= len) */

	if (!cmp)
		*occupied = 1;
	else {
		*occupied = 0;
		if (insert_new && i < len) {
			MOVE_ARRAY(list + i + 1, list + i, len - i);
			memset(list + i, 0, sizeof(struct notes_merge_pair));
		}
	}
	last_index = i;
	return list + i;
}

static struct object_id uninitialized = {
	"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff" \
	"\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff"
};

static struct notes_merge_pair *diff_tree_remote(struct notes_merge_options *o,
						 const struct object_id *base,
						 const struct object_id *remote,
						 int *num_changes)
{
	struct diff_options opt;
	struct notes_merge_pair *changes;
	int i, len = 0;

	trace_printf("\tdiff_tree_remote(base = %.7s, remote = %.7s)\n",
	       oid_to_hex(base), oid_to_hex(remote));

	diff_setup(&opt);
	DIFF_OPT_SET(&opt, RECURSIVE);
	opt.output_format = DIFF_FORMAT_NO_OUTPUT;
	diff_setup_done(&opt);
	diff_tree_oid(base, remote, "", &opt);
	diffcore_std(&opt);

	changes = xcalloc(diff_queued_diff.nr, sizeof(struct notes_merge_pair));

	for (i = 0; i < diff_queued_diff.nr; i++) {
		struct diff_filepair *p = diff_queued_diff.queue[i];
		struct notes_merge_pair *mp;
		int occupied;
		struct object_id obj;

		if (verify_notes_filepair(p, &obj)) {
			trace_printf("\t\tCannot merge entry '%s' (%c): "
			       "%.7s -> %.7s. Skipping!\n", p->one->path,
			       p->status, oid_to_hex(&p->one->oid),
			       oid_to_hex(&p->two->oid));
			continue;
		}
		mp = find_notes_merge_pair_pos(changes, len, &obj, 1, &occupied);
		if (occupied) {
			/* We've found an addition/deletion pair */
			assert(!oidcmp(&mp->obj, &obj));
			if (is_null_oid(&p->one->oid)) { /* addition */
				assert(is_null_oid(&mp->remote));
				oidcpy(&mp->remote, &p->two->oid);
			} else if (is_null_oid(&p->two->oid)) { /* deletion */
				assert(is_null_oid(&mp->base));
				oidcpy(&mp->base, &p->one->oid);
			} else
				assert(!"Invalid existing change recorded");
		} else {
			oidcpy(&mp->obj, &obj);
			oidcpy(&mp->base, &p->one->oid);
			oidcpy(&mp->local, &uninitialized);
			oidcpy(&mp->remote, &p->two->oid);
			len++;
		}
		trace_printf("\t\tStored remote change for %s: %.7s -> %.7s\n",
		       oid_to_hex(&mp->obj), oid_to_hex(&mp->base),
		       oid_to_hex(&mp->remote));
	}
	diff_flush(&opt);
	clear_pathspec(&opt.pathspec);

	*num_changes = len;
	return changes;
}

static void diff_tree_local(struct notes_merge_options *o,
			    struct notes_merge_pair *changes, int len,
			    const struct object_id *base,
			    const struct object_id *local)
{
	struct diff_options opt;
	int i;

	trace_printf("\tdiff_tree_local(len = %i, base = %.7s, local = %.7s)\n",
	       len, oid_to_hex(base), oid_to_hex(local));

	diff_setup(&opt);
	DIFF_OPT_SET(&opt, RECURSIVE);
	opt.output_format = DIFF_FORMAT_NO_OUTPUT;
	diff_setup_done(&opt);
	diff_tree_oid(base, local, "", &opt);
	diffcore_std(&opt);

	for (i = 0; i < diff_queued_diff.nr; i++) {
		struct diff_filepair *p = diff_queued_diff.queue[i];
		struct notes_merge_pair *mp;
		int match;
		struct object_id obj;

		if (verify_notes_filepair(p, &obj)) {
			trace_printf("\t\tCannot merge entry '%s' (%c): "
			       "%.7s -> %.7s. Skipping!\n", p->one->path,
			       p->status, oid_to_hex(&p->one->oid),
			       oid_to_hex(&p->two->oid));
			continue;
		}
		mp = find_notes_merge_pair_pos(changes, len, &obj, 0, &match);
		if (!match) {
			trace_printf("\t\tIgnoring local-only change for %s: "
			       "%.7s -> %.7s\n", oid_to_hex(&obj),
			       oid_to_hex(&p->one->oid),
			       oid_to_hex(&p->two->oid));
			continue;
		}

		assert(!oidcmp(&mp->obj, &obj));
		if (is_null_oid(&p->two->oid)) { /* deletion */
			/*
			 * Either this is a true deletion (1), or it is part
			 * of an A/D pair (2), or D/A pair (3):
			 *
			 * (1) mp->local is uninitialized; set it to null_sha1
			 * (2) mp->local is not uninitialized; don't touch it
			 * (3) mp->local is uninitialized; set it to null_sha1
			 *     (will be overwritten by following addition)
			 */
			if (!oidcmp(&mp->local, &uninitialized))
				oidclr(&mp->local);
		} else if (is_null_oid(&p->one->oid)) { /* addition */
			/*
			 * Either this is a true addition (1), or it is part
			 * of an A/D pair (2), or D/A pair (3):
			 *
			 * (1) mp->local is uninitialized; set to p->two->sha1
			 * (2) mp->local is uninitialized; set to p->two->sha1
			 * (3) mp->local is null_sha1;     set to p->two->sha1
			 */
			assert(is_null_oid(&mp->local) ||
			       !oidcmp(&mp->local, &uninitialized));
			oidcpy(&mp->local, &p->two->oid);
		} else { /* modification */
			/*
			 * This is a true modification. p->one->sha1 shall
			 * match mp->base, and mp->local shall be uninitialized.
			 * Set mp->local to p->two->sha1.
			 */
			assert(!oidcmp