comparison mercurial/chgserver.py @ 45852:b56feaa9b520

chgserver: backport py3 buffered I/O workarounds from procutil

I've recently switched to new machine and I found chg's stdout is fully
buffered.

Even though chg server is a daemon process, it inherits the environment
where the chg client originally forked the server. This means the server's
stdout might have been wrapped by LineBufferedWrapper. That's why we need
to do wrap/unwrap in both ways.

The "if" condition in _restoreio() looks weird, but I'm not willing to
clean things up because stdio behavior is fundamentally different between
py2 and py3, and py2 support will be dropped anyway.

45847:d68618954ade

            # to see output immediately on pager, the mode stays unchanged
            # when client re-attached. ferr is unchanged because it should
            # be unbuffered no matter if it is a tty or not.
            if fn == b'ferr':
                newfp = fp
            else:
                # make it line buffered explicitly because the default is
                # decided on first write(), where fout could be a pager.
                if fp.isatty():
                    bufsize = 1  # line buffered
                else:
                    bufsize = -1  # system default
                newfp = os.fdopen(fp.fileno(), mode, bufsize)
                setattr(ui, fn, newfp)
            setattr(self, cn, newfp)

        self._ioattached = True
        self.cresult.write(struct.pack(b'>i', len(clientfds)))

            return
        nullfd = os.open(os.devnull, os.O_WRONLY)
        ui = self.ui
        for (ch, fp, fd), (cn, fn, mode) in zip(self._oldios, _iochannels):
            newfp = getattr(ui, fn)
            # close newfp while it's associated with client; otherwise it
            # would be closed when newfp is deleted
            if newfp is not fp:
                newfp.close()
            # restore original fd: fp is open again
            try:
                if newfp is fp and 'w' in mode:
                    # Discard buffered data which couldn't be flushed because
                    # of EPIPE. The data should belong to the current session
                    # and should never persist.
                    os.dup2(nullfd, fp.fileno())
                    fp.flush()

45852:b56feaa9b520

            # to see output immediately on pager, the mode stays unchanged
            # when client re-attached. ferr is unchanged because it should
            # be unbuffered no matter if it is a tty or not.
            if fn == b'ferr':
                newfp = fp
            elif pycompat.ispy3:
                # On Python 3, the standard library doesn't offer line-buffered
                # binary streams, so wrap/unwrap it.
                if fp.isatty():
                    newfp = procutil.make_line_buffered(fp)
                else:
                    newfp = procutil.unwrap_line_buffered(fp)
            else:
                # Python 2 uses the I/O streams provided by the C library, so
                # make it line-buffered explicitly. Otherwise the default would
                # be decided on first write(), where fout could be a pager.
                if fp.isatty():
                    bufsize = 1  # line buffered
                else:
                    bufsize = -1  # system default
                newfp = os.fdopen(fp.fileno(), mode, bufsize)
            if newfp is not fp:
                setattr(ui, fn, newfp)
            setattr(self, cn, newfp)

        self._ioattached = True
        self.cresult.write(struct.pack(b'>i', len(clientfds)))

            return
        nullfd = os.open(os.devnull, os.O_WRONLY)
        ui = self.ui
        for (ch, fp, fd), (cn, fn, mode) in zip(self._oldios, _iochannels):
            newfp = getattr(ui, fn)
            # On Python 2, newfp and fp may be separate file objects associated
            # with the same fd, so we must close newfp while it's associated
            # with the client. Otherwise the new associated fd would be closed
            # when newfp gets deleted. On Python 3, newfp is just a wrapper
            # around fp even if newfp is not fp, so deleting newfp is safe.
            if not (pycompat.ispy3 or newfp is fp):
                newfp.close()
            # restore original fd: fp is open again
            try:
                if (pycompat.ispy3 or newfp is fp) and 'w' in mode:
                    # Discard buffered data which couldn't be flushed because
                    # of EPIPE. The data should belong to the current session
                    # and should never persist.
                    os.dup2(nullfd, fp.fileno())
                    fp.flush()