mercurial/mpatch.h

py3: add "b" prefix to string literals related to module policy

String literals without explicit prefix in __init__.py and policy.py
are treated as unicode object on Python3, because these modules are
loaded before setup of our specific code transformation (the later
module is imported at the beginning of __init__.py).

BTW, "modulepolicy" in __init__.py is initialized by "policy.policy".

This causes issues below;

  - checking "policy" value in other modules causes unintentional result

    For example, "b'py' not in (u'c', u'py')" returns True
    unintentionally on Python3.

  - writing "policy" out fails at conversion from unicode to bytes

    62939e0148f1 fixed this issue for default code path, but "policy"
    can be overridden by HGMODULEPOLICY environment variable (it should
    be rare case for developer using Python3, though).

This patch does:

  - add "b" prefix to all string literals, which are related to module
    policy, in modules above.

  - check existence of HGMODULEPOLICY, and overwrite "policy" only if
    it exists

    For simplicity, this patch omits checking "supports_bytes_environ",
    switching os.environ/os.environb, and so on (Yuya agreed this in
    personal talking)

#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