Vendor dockerpty at c8b493553477c9a57d163c71c97b2102f44a6ce7

Include TLS fixes and relative imports:

c8b4935534

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>

fig/packages/dockerpty/tty.py

@@ -0,0 +1,130 @@
+# dockerpty: tty.py
+#
+# Copyright 2014 Chris Corbyn <chris@w3style.co.uk>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from __future__ import absolute_import
+
+import os
+import termios
+import tty
+import fcntl
+import struct
+
+
+def size(fd):
+    """
+    Return a tuple (rows,cols) representing the size of the TTY `fd`.
+
+    The provided file descriptor should be the stdout stream of the TTY.
+
+    If the TTY size cannot be determined, returns None.
+    """
+
+    if not os.isatty(fd.fileno()):
+        return None
+
+    try:
+        dims = struct.unpack('hh', fcntl.ioctl(fd, termios.TIOCGWINSZ, 'hhhh'))
+    except:
+        try:
+            dims = (os.environ['LINES'], os.environ['COLUMNS'])
+        except:
+            return None
+
+    return dims
+
+
+class Terminal(object):
+    """
+    Terminal provides wrapper functionality to temporarily make the tty raw.
+
+    This is useful when streaming data from a pseudo-terminal into the tty.
+
+    Example:
+
+        with Terminal(sys.stdin, raw=True):
+            do_things_in_raw_mode()
+    """
+
+    def __init__(self, fd, raw=True):
+        """
+        Initialize a terminal for the tty with stdin attached to `fd`.
+
+        Initializing the Terminal has no immediate side effects. The `start()`
+        method must be invoked, or `with raw_terminal:` used before the
+        terminal is affected.
+        """
+
+        self.fd = fd
+        self.raw = raw
+        self.original_attributes = None
+
+
+    def __enter__(self):
+        """
+        Invoked when a `with` block is first entered.
+        """
+
+        self.start()
+        return self
+
+
+    def __exit__(self, *_):
+        """
+        Invoked when a `with` block is finished.
+        """
+
+        self.stop()
+
+
+    def israw(self):
+        """
+        Returns True if the TTY should operate in raw mode.
+        """
+
+        return self.raw
+
+
+    def start(self):
+        """
+        Saves the current terminal attributes and makes the tty raw.
+
+        This method returns None immediately.
+        """
+
+        if os.isatty(self.fd.fileno()) and self.israw():
+            self.original_attributes = termios.tcgetattr(self.fd)
+            tty.setraw(self.fd)
+
+
+    def stop(self):
+        """
+        Restores the terminal attributes back to before setting raw mode.
+
+        If the raw terminal was not started, does nothing.
+        """
+
+        if self.original_attributes is not None:
+            termios.tcsetattr(
+                self.fd,
+                termios.TCSADRAIN,
+                self.original_attributes,
+            )
+
+    def __repr__(self):
+        return "{cls}({fd}, raw={raw})".format(
+            cls=type(self).__name__,
+            fd=self.fd,
+            raw=self.raw)