annotate mercurial/mpatch.h @ 42446:055c3e2c44f0

revlog: speed up isancestor

Currently, it is implemented on top of commonancestorsheads.
Implement it on top of reachableroots instead, as reachableroots could
stop walking the graph much sooner than commonancestorsheads.

Measuring repo.changelog.isancestorrev on two revisions in a private repository:
before: ! wall 0.005175 comb 0.010000 user 0.010000 sys 0.000000 (best of 550)
after : ! wall 0.000072 comb 0.000000 user 0.000000 sys 0.000000 (best of 36199)

When hg does this kind of operations 1500 times in pull ->
bookmarks.comparebookmarks -> bookmarks.validdest, that's 11s that
drop from the --profile output.

Differential Revision: https://phab.mercurial-scm.org/D6506

#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