| # This Source Code Form is subject to the terms of the Mozilla Public |
| # License, v. 2.0. If a copy of the MPL was not distributed with this |
| # file, You can obtain one at http://mozilla.org/MPL/2.0/. |
| |
| """This file contains code for interacting with terminals. |
| |
| All the terminal interaction code is consolidated so the complexity can be in |
| one place, away from code that is commonly looked at. |
| """ |
| |
| from __future__ import print_function, unicode_literals |
| |
| import logging |
| import sys |
| |
| |
| class LoggingHandler(logging.Handler): |
| """Custom logging handler that works with terminal window dressing. |
| |
| This is alternative terminal logging handler which contains smarts for |
| emitting terminal control characters properly. Currently, it has generic |
| support for "footer" elements at the bottom of the screen. Functionality |
| can be added when needed. |
| """ |
| def __init__(self): |
| logging.Handler.__init__(self) |
| |
| self.fh = sys.stdout |
| self.footer = None |
| |
| def flush(self): |
| self.acquire() |
| |
| try: |
| self.fh.flush() |
| finally: |
| self.release() |
| |
| def emit(self, record): |
| msg = self.format(record) |
| |
| if self.footer: |
| self.footer.clear() |
| |
| self.fh.write(msg) |
| self.fh.write('\n') |
| |
| if self.footer: |
| self.footer.draw() |
| |
| # If we don't flush, the footer may not get drawn. |
| self.flush() |
| |
| |
| class TerminalFooter(object): |
| """Represents something drawn on the bottom of a terminal.""" |
| def __init__(self, terminal): |
| self.t = terminal |
| self.fh = sys.stdout |
| |
| def _clear_lines(self, n): |
| for i in xrange(n): |
| self.fh.write(self.t.move_x(0)) |
| self.fh.write(self.t.clear_eol()) |
| self.fh.write(self.t.move_up()) |
| |
| self.fh.write(self.t.move_down()) |
| self.fh.write(self.t.move_x(0)) |
| |
| def clear(self): |
| raise Exception('clear() must be implemented.') |
| |
| def draw(self): |
| raise Exception('draw() must be implemented.') |
| |
