view mercurial/cffi/mpatchbuild.py @ 39037:ede768cfe83e

mail: always fall back to iso-8859-1 if us-ascii won't work (BC)

It looks like this was a well-intentioned backwards compat hack for
previewing the output of `hg email` in a stable way. Unfortunately I
think this hack's time has come, because Python 3 does a much better
job of ensuring it actually emits *valid* email messages. In
particular, Python 2 would blindly trust us that the bytes we handed
it were valid for the encoding we claimed, but Python 3 has some more
sniff-tests that we end up failing.

As a result, if we're going to print an email to the terminal, try
us-ascii first, but if that fails go straight to iso-8859-1 which
should be reasonably readable for ascii-compatible patch bodies. This
*will* be a breaking change for ascii-incompatible textual patch
content, but I don't think that's avoidable if we want to continue
using the email library from the stdlib.

.. bc::

  Emails from the patchbomb extension will always be printed as though
  they are iso-8859-1 if they're not valid us-ascii. Previously,
  previewed emails were always claimed to be us-ascii and might
  contain invalid byte sequences.

Differential Revision: https://phab.mercurial-scm.org/D4231

from __future__ import absolute_import

import cffi
import os

ffi = cffi.FFI()
mpatch_c = os.path.join(os.path.join(os.path.dirname(__file__), '..',
                                     'mpatch.c'))
with open(mpatch_c) as f:
    ffi.set_source("mercurial.cffi._mpatch", f.read(),
                   include_dirs=["mercurial"])
ffi.cdef("""

struct mpatch_frag {
       int start, end, len;
       const char *data;
};

struct mpatch_flist {
       struct mpatch_frag *base, *head, *tail;
};

extern "Python" struct mpatch_flist* cffi_get_next_item(void*, ssize_t);

int mpatch_decode(const char *bin, ssize_t len, struct mpatch_flist** res);
ssize_t mpatch_calcsize(size_t len, struct mpatch_flist *l);
void mpatch_lfree(struct mpatch_flist *a);
static int mpatch_apply(char *buf, const char *orig, size_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);
""")

if __name__ == '__main__':
    ffi.compile()