164 lines
4.7 KiB
Python
164 lines
4.7 KiB
Python
import os
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import curses
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import time
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import threading
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from curses import textpad
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from contextlib import contextmanager
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class EscapePressed(Exception):
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pass
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def text_input(window):
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"""
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Transform a window into a text box that will accept user input and loop
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until an escape sequence is entered.
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If enter is pressed, return the input text as a string.
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If escape is pressed, return None.
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"""
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window.clear()
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curses.curs_set(2)
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textbox = textpad.Textbox(window, insert_mode=True)
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def validate(ch):
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"Filters characters for special key sequences"
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if ch == 27:
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raise EscapePressed
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return ch
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# Wrapping in an exception block so that we can distinguish when the user
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# hits the return character from when the user tries to back out of the
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# input.
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try:
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out = textbox.edit(validate=validate)
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out = out.strip()
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except EscapePressed:
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out = None
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curses.curs_set(0)
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return out
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class LoadScreen(object):
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def __init__(self, stdscr):
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self._stdscr = stdscr
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self._args = None
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self._animator = None
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self._is_running = None
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def __call__(
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self,
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delay=0.5,
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interval=0.4,
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message='Downloading',
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trail='...'):
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self._args = (delay, interval, message, trail)
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return self
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def __enter__(self):
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self._animator = threading.Thread(target=self.animate, args=self._args)
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self._animator.daemon = True
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self._is_running = True
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self._animator.start()
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def __exit__(self, exc_type, exc_val, exc_tb):
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self._is_running = False
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self._animator.join()
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def animate(self, delay, interval, message, trail):
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# Delay before starting animation to avoid wasting resources if the
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# wait time is very short
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start = time.time()
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while (time.time() - start) < delay:
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if not self._is_running:
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return
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message_len = len(message) + len(trail)
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n_rows, n_cols = self._stdscr.getmaxyx()
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s_row = (n_rows - 2) / 2
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s_col = (n_cols - message_len - 1) / 2
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window = self._stdscr.derwin(3, message_len+2, s_row, s_col)
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while True:
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for i in xrange(len(trail)+1):
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if not self._is_running:
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# TODO: figure out why this isn't removing the screen
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del window
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self._stdscr.refresh()
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return
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window.erase()
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window.border()
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window.addstr(1, 1, message + trail[:i])
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window.refresh()
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time.sleep(interval)
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@contextmanager
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def curses_session():
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try:
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# Curses must wait for some time after the Escape key is pressed to see
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# check if it is the beginning of an escape sequence indicating a
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# special key. The default wait time is 1 second, which means that
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# getch() will not return the escape key (ord(27)), until a full second
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# after it has been pressed. Turn this down to 25 ms, which is close to
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# what VIM uses.
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# http://stackoverflow.com/questions/27372068
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os.environ['ESCDELAY'] = '25'
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# Initialize curses
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stdscr = curses.initscr()
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# Turn off echoing of keys, and enter cbreak mode,
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# where no buffering is performed on keyboard input
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curses.noecho()
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curses.cbreak()
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# In keypad mode, escape sequences for special keys
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# (like the cursor keys) will be interpreted and
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# a special value like curses.KEY_LEFT will be returned
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stdscr.keypad(1)
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# Start color, too. Harmless if the terminal doesn't have
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# color; user can test with has_color() later on. The try/catch
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# works around a minor bit of over-conscientiousness in the curses
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# module -- the error return from C start_color() is ignorable.
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try:
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curses.start_color()
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# Assign the terminal's default (background) color to code -1
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curses.use_default_colors()
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except:
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pass
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# Hide blinking cursor
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curses.curs_set(0)
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# Initialize color pairs - colored text on the default background
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curses.init_pair(1, curses.COLOR_RED, -1)
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curses.init_pair(2, curses.COLOR_GREEN, -1)
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curses.init_pair(3, curses.COLOR_YELLOW, -1)
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curses.init_pair(4, curses.COLOR_BLUE, -1)
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curses.init_pair(5, curses.COLOR_MAGENTA, -1)
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curses.init_pair(6, curses.COLOR_CYAN, -1)
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yield stdscr
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finally:
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if stdscr is not None:
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stdscr.keypad(0)
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curses.echo()
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curses.nocbreak()
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curses.endwin() |