comparison mercurial/windows.py @ 39820:68ea1f8dcb84

py3: proxy posixfile objects to re-add a useful 'name' attribute on Windows

This file object is used in the vfs layer, so there are many errors like this:

    ...
      File "mercurial\localrepo.py", line 2569, in savecommitmessage
        return self.pathto(fp.name[len(self.root) + 1:])
    TypeError: 'int' object is not subscriptable

It looks like the 'name' value is actually the fileno() value, and the
documentation says the name parameter to PyFile_FromFd() is ignored. [1]  I
tried just assigning the attribute after osutil.posixfile() returns, but that
crashes saying that it's read-only.

[1] https://docs.python.org/3.6/c-api/file.html

39819:fb628c048d64

            self._noopseek()

        object.__setattr__(self, r'_lastop', self.OPREAD)
        return self._fp.readlines(*args, **kwargs)

def posixfile(name, mode='r', buffering=-1):
    '''Open a file with even more POSIX-like semantics'''
    try:
        fp = osutil.posixfile(name, mode, buffering) # may raise WindowsError

        # The position when opening in append mode is implementation defined, so
        # make it consistent with other platforms, which position at EOF.
        if 'a' in mode:
            fp.seek(0, os.SEEK_END)

39820:68ea1f8dcb84

            self._noopseek()

        object.__setattr__(self, r'_lastop', self.OPREAD)
        return self._fp.readlines(*args, **kwargs)

class fdproxy(object):
    """Wraps osutil.posixfile() to override the name attribute to reflect the
    underlying file name.
    """
    def __init__(self, name, fp):
        self.name = name
        self._fp = fp

    def __enter__(self):
        return self._fp.__enter__()

    def __exit__(self, exc_type, exc_value, traceback):
        self._fp.__exit__(exc_type, exc_value, traceback)

    def __iter__(self):
        return iter(self._fp)

    def __getattr__(self, name):
        return getattr(self._fp, name)

def posixfile(name, mode='r', buffering=-1):
    '''Open a file with even more POSIX-like semantics'''
    try:
        fp = osutil.posixfile(name, mode, buffering) # may raise WindowsError

        # PyFile_FromFd() ignores the name, and seems to report fp.name as the
        # underlying file descriptor.
        if pycompat.ispy3:
            fp = fdproxy(name, fp)

        # The position when opening in append mode is implementation defined, so
        # make it consistent with other platforms, which position at EOF.
        if 'a' in mode:
            fp.seek(0, os.SEEK_END)