mercurial/mpatch.h

narrow: call narrowspec.{save,restore,clear}backup directly

I want to move .hg/narrowspec to .hg/store/narrowspec and we need to
decouple the narrowspec update from the dirstate update for that. This
patch lets the callers call the narrowspec backup functions directly,
in addition to the dirstate backup functions. The narrowspec methods
are made to check if narrowing is enabled. For that, a repo instance
was needed, which all the callers luckily already had available.

Differential Revision: https://phab.mercurial-scm.org/D4096

#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