view mercurial/mpatch.h @ 45999:c4c7a6b61146

match: skip walking up the directory hierarchy if the number of pats are small

Previously, we would receive a path like abc/def/ghi and "walk up" the directory
hierarchy, checking abc/def, abc, and `b''` to see if they were in the set of
prefixes that this matcher covered. We did this indiscriminately - we generated
all of these paths even if the set of prefixes the matcher covered was
completely empty, which is the case for a lot of repos at my company (the narrow
matcher we use is usually non-recursive).

This brings the time for a rebase in one of my repos from 12.20s to 10.87s. In
this particular repo, this is entirely due to the `len(prefix_set) == 0` check,
as I do not have any recursive patterns in the narrowspec.

Differential Revision: https://phab.mercurial-scm.org/D9488

#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