mercurial/mpatch.h

destutil: if wdp is obsolete, update to the closest non-obsolete ancestor

As the original comments suggest, using prune as a model here was an existing
idea, and now this patch implements it.

I think it would be even better to do what solveobswdp() from evolve does (in
short, it allows to update to a successor of the closest ancestor even if that
ancestor is obsolete), but that is outside of this series' scope.

Differential Revision: https://phab.mercurial-scm.org/D12099

#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