mercurial/mpatch.h

dispatch: add HGPLAIN=+strictflags to restrict early parsing of global options

If this feature is enabled, early options are parsed using the global options
table. As the parser stops processing options when non/unknown option is
encountered, it won't mistakenly take an option value as a new early option.
Still "--" can be injected to terminate the parsing (e.g. "hg -R -- log"), I
think it's unlikely to lead to an RCE.

To minimize a risk of this change, new fancyopts.earlygetopt() path is enabled
only when +strictflags is set. Also the strict parser doesn't support '--repo',
a short for '--repository' yet. This limitation will be removed later.

As this feature is backward incompatible, I decided to add a new opt-in
mechanism to HGPLAIN. I'm not pretty sure if this is the right choice, but
I'm thinking of adding +feature/-feature syntax to HGPLAIN. Alternatively,
we could add a new environment variable. Any bikeshedding is welcome.

Note that HGPLAIN=+strictflags doesn't work correctly in chg session since
command arguments are pre-processed in C. This wouldn't be easily fixed.

#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