view mercurial/mpatch.h @ 41932:7694b685bb10

copies: handle a case when both merging csets are not descendant of merge base

This patch fix the behaviour of fullcopytracing algorithm in the case
when both the merging csets are not the descendant of merge base.
Although it seems to be the rare case when both the csets are not
descendant of merge base. But it can be seen in most of cases of
content-divergence in evolve extension, where merge base is the common
predecessor.
Previous patch added a test where this algorithm can fail to continue
because of an assumption that only one of the two csets can be dirty.
This patch fix that error.

For refrence I suggest you to look into the previous discussion held
on a patch sent by Pulkit: https://phab.mercurial-scm.org/D3896

Differential Revision: https://phab.mercurial-scm.org/D5963

#ifndef _HG_MPATCH_H_
#define _HG_MPATCH_H_

#define MPATCH_ERR_NO_MEM -3
#define MPATCH_ERR_CANNOT_BE_DECODED -2
#define MPATCH_ERR_INVALID_PATCH -1

struct mpatch_frag {
	int start, end, len;
	const char *data;
};

struct mpatch_flist {
	struct mpatch_frag *base, *head, *tail;
};

int mpatch_decode(const char *bin, ssize_t len, struct mpatch_flist **res);
ssize_t mpatch_calcsize(ssize_t len, struct mpatch_flist *l);
void mpatch_lfree(struct mpatch_flist *a);
int mpatch_apply(char *buf, const char *orig, ssize_t len,
                 struct mpatch_flist *l);
struct mpatch_flist *
mpatch_fold(void *bins, struct mpatch_flist *(*get_next_item)(void *, ssize_t),
            ssize_t start, ssize_t end);

#endif