setup_bdiff_cffi.py

localrepo: make invalidate avoid invalidating store inside transaction (API)

Before this patch, invalidate() discards in-memory fncache changes,
even inside transaction scope.

Such changes should be written out at closing transaction. Otherwise,
fncache might overlook newly added files. A file overlooked by
fncache isn't accessible via store vfs, even if it actually exists in
store.

On the other hand, a non-existing file in fncache is less harmful,
because fncachestore always examines whether a file actually exists or
not before access. Therefore, discarding in-memory changes can be
safely omitted.

It is typical case that repo.invalidate() in streamclone is executed
inside nested transaction.

This patch makes invalidate() avoid invalidating store inside
transaction.

This patch focuses on describing only how invalidate() changes own
behavior according to activity of transaction. Describing other detail
of invalidate() in docstr will be done in another series, which
refactors invalidate*() functions.

from __future__ import absolute_import

import cffi
import os

ffi = cffi.FFI()
ffi.set_source("_bdiff_cffi",
    open(os.path.join(os.path.join(os.path.dirname(__file__), 'mercurial'),
        'bdiff.c')).read(), include_dirs=['mercurial'])
ffi.cdef("""
struct bdiff_line {
    int hash, n, e;
    ssize_t len;
    const char *l;
};

struct bdiff_hunk;
struct bdiff_hunk {
    int a1, a2, b1, b2;
    struct bdiff_hunk *next;
};

int bdiff_splitlines(const char *a, ssize_t len, struct bdiff_line **lr);
int bdiff_diff(struct bdiff_line *a, int an, struct bdiff_line *b, int bn,
    struct bdiff_hunk *base);
void bdiff_freehunks(struct bdiff_hunk *l);
void free(void*);
""")

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