merge: make applyupdates() not mutate mresult argument
We have an extension at work that overrides `merge.applyupdates()` to
make it skip some writes and instead instruct the virtual filesystem
we use to get a different version. That override doesn't work
correctly when doing `hg co -m` and there's a modified file in the
dirstate that's deleted in the destination. That's because
`applyupdates()` mutates its `mresult` argument and our extension had
passed in a modified copied of `mresult` to the overridden function,
which resulted in the mutation not having any effect. This patch fixes
that by letting the caller (i.e. `merge._update()`) update `mresult`
with the extra actions instead. Besides fixing our internal extension,
that seems cleaner to me anyway (better to not mutate `mresult` only
in some cases and we can skip some of the logic if we're not going to
update the dirstate anyway).
Differential Revision: https://phab.mercurial-scm.org/D10830
#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