view mercurial/cffi/osutil.py @ 45214:6063c1857d0a stable

exchange: backout changeset c26335fa4225

Changeset c26335fa4225 has good intends but introduce significant behavior
regressions for multiple important cases. In short there are many case where
push would have caught instability creation/propagation that are no longer
covered.  These behavior have been covered for many years and even if some
related case are not currently caught, the covered one should not be regressed.

The next four changesets introduce tests for some of these cases. However we
could produce many more tests cases since the area is wide and they are many
possible combination. (And we should cover them when getting back to this issue)

Since 5.5 is one week away, the most reasonable approach seems to back this out
while we devise a new way to move forward that preserve the current behavior,
catch more issues and also improves the situation that c26335fa4225 target.


In addition to the behavior change, c26335fa4225 also introduced output
changes. These output changes does not requires a backout per-se, but are part of
the same changeset. However they come with a couple of issues that also requires
attention:

1) the bulk of the error message have been shoehorned into a multiple line abort
message. This seems quite different from what we usually do. The abort message
should be a compact and efficient message, with extra details being issued as
normal error output beforehand. (with --verbose/--quiet) support.

2) the current output is unbounded, so if there is many (tens, hundreds,
thousands, …) of unstable/obsolete changeset involved in the push, the output
can quickly become a scary and un-usuable wall of text. So we need some
limitation here (same as we have with the remote head list that says A, B , C
and # others).

# osutil.py - CFFI version of osutil.c
#
# Copyright 2016 Maciej Fijalkowski <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

import os
import stat as statmod

from ..pure.osutil import *

from .. import pycompat

if pycompat.isdarwin:
    from . import _osutil

    ffi = _osutil.ffi
    lib = _osutil.lib

    listdir_batch_size = 4096
    # tweakable number, only affects performance, which chunks
    # of bytes do we get back from getattrlistbulk

    attrkinds = [None] * 20  # we need the max no for enum VXXX, 20 is plenty

    attrkinds[lib.VREG] = statmod.S_IFREG
    attrkinds[lib.VDIR] = statmod.S_IFDIR
    attrkinds[lib.VLNK] = statmod.S_IFLNK
    attrkinds[lib.VBLK] = statmod.S_IFBLK
    attrkinds[lib.VCHR] = statmod.S_IFCHR
    attrkinds[lib.VFIFO] = statmod.S_IFIFO
    attrkinds[lib.VSOCK] = statmod.S_IFSOCK

    class stat_res(object):
        def __init__(self, st_mode, st_mtime, st_size):
            self.st_mode = st_mode
            self.st_mtime = st_mtime
            self.st_size = st_size

    tv_sec_ofs = ffi.offsetof(b"struct timespec", b"tv_sec")
    buf = ffi.new(b"char[]", listdir_batch_size)

    def listdirinternal(dfd, req, stat, skip):
        ret = []
        while True:
            r = lib.getattrlistbulk(dfd, req, buf, listdir_batch_size, 0)
            if r == 0:
                break
            if r == -1:
                raise OSError(ffi.errno, os.strerror(ffi.errno))
            cur = ffi.cast(b"val_attrs_t*", buf)
            for i in range(r):
                lgt = cur.length
                assert lgt == ffi.cast(b'uint32_t*', cur)[0]
                ofs = cur.name_info.attr_dataoffset
                str_lgt = cur.name_info.attr_length
                base_ofs = ffi.offsetof(b'val_attrs_t', b'name_info')
                name = str(
                    ffi.buffer(
                        ffi.cast(b"char*", cur) + base_ofs + ofs, str_lgt - 1
                    )
                )
                tp = attrkinds[cur.obj_type]
                if name == b"." or name == b"..":
                    continue
                if skip == name and tp == statmod.S_ISDIR:
                    return []
                if stat:
                    mtime = cur.mtime.tv_sec
                    mode = (cur.accessmask & ~lib.S_IFMT) | tp
                    ret.append(
                        (
                            name,
                            tp,
                            stat_res(
                                st_mode=mode,
                                st_mtime=mtime,
                                st_size=cur.datalength,
                            ),
                        )
                    )
                else:
                    ret.append((name, tp))
                cur = ffi.cast(
                    b"val_attrs_t*", int(ffi.cast(b"intptr_t", cur)) + lgt
                )
        return ret

    def listdir(path, stat=False, skip=None):
        req = ffi.new(b"struct attrlist*")
        req.bitmapcount = lib.ATTR_BIT_MAP_COUNT
        req.commonattr = (
            lib.ATTR_CMN_RETURNED_ATTRS
            | lib.ATTR_CMN_NAME
            | lib.ATTR_CMN_OBJTYPE
            | lib.ATTR_CMN_ACCESSMASK
            | lib.ATTR_CMN_MODTIME
        )
        req.fileattr = lib.ATTR_FILE_DATALENGTH
        dfd = lib.open(path, lib.O_RDONLY, 0)
        if dfd == -1:
            raise OSError(ffi.errno, os.strerror(ffi.errno))

        try:
            ret = listdirinternal(dfd, req, stat, skip)
        finally:
            try:
                lib.close(dfd)
            except BaseException:
                pass  # we ignore all the errors from closing, not
                # much we can do about that
        return ret