class MainLoop(object):
"""
This is the standard main loop implementation for a single interactive
session.
:param widget: the topmost widget used for painting the screen, stored as
:attr:`widget` and may be modified. Must be a box widget.
:type widget: widget instance
:param palette: initial palette for screen
:type palette: iterable of palette entries
:param screen: screen to use, default is a new :class:`raw_display.Screen`
instance; stored as :attr:`screen`
:type screen: display module screen instance
:param handle_mouse: ``True`` to ask :attr:`.screen` to process mouse events
:type handle_mouse: bool
:param input_filter: a function to filter input before sending it to
:attr:`.widget`, called from :meth:`.input_filter`
:type input_filter: callable
:param unhandled_input: a function called when input is not handled by
:attr:`.widget`, called from :meth:`.unhandled_input`
:type unhandled_input: callable
:param event_loop: if :attr:`.screen` supports external an event loop it may be
given here, default is a new :class:`SelectEventLoop` instance;
stored as :attr:`.event_loop`
:type event_loop: event loop instance
:param pop_ups: `True` to wrap :attr:`.widget` with a :class:`PopUpTarget`
instance to allow any widget to open a pop-up anywhere on the screen
:type pop_ups: boolean
.. attribute:: screen
The screen object this main loop uses for screen updates and reading input
.. attribute:: event_loop
The event loop object this main loop uses for waiting on alarms and IO
"""
def __init__(self, widget, palette=(), screen=None,
handle_mouse=True, input_filter=None, unhandled_input=None,
event_loop=None, pop_ups=False):
self._widget = widget
self.handle_mouse = handle_mouse
self.pop_ups = pop_ups # triggers property setting side-effect
if not screen:
from urwid import raw_display
screen = raw_display.Screen()
if palette:
screen.register_palette(palette)
self.screen = screen
self.screen_size = None
self._unhandled_input = unhandled_input
self._input_filter = input_filter
if not hasattr(screen, 'get_input_descriptors'
) and event_loop is not None:
raise NotImplementedError("screen object passed "
"%r does not support external event loops" % (screen,))
if event_loop is None:
event_loop = SelectEventLoop()
self.event_loop = event_loop
self._input_timeout = None
self._watch_pipes = {}
def _set_widget(self, widget):
self._widget = widget
if self.pop_ups:
self._topmost_widget.original_widget = self._widget
else:
self._topmost_widget = self._widget
widget = property(lambda self:self._widget, _set_widget, doc=
"""
Property for the topmost widget used to draw the screen.
This must be a box widget.
""")
def _set_pop_ups(self, pop_ups):
self._pop_ups = pop_ups
if pop_ups:
self._topmost_widget = PopUpTarget(self._widget)
else:
self._topmost_widget = self._widget
pop_ups = property(lambda self:self._pop_ups, _set_pop_ups)
def set_alarm_in(self, sec, callback, user_data=None):
"""
Schedule an alarm in *sec* seconds that will call *callback* from the
within the :meth:`run` method.
:param sec: seconds until alarm
:type sec: float
:param callback: function to call with two parameters: this main loop
object and *user_data*
:type callback: callable
"""
def cb():
callback(self, user_data)
return self.event_loop.alarm(sec, cb)
def set_alarm_at(self, tm, callback, user_data=None):
"""
Schedule an alarm at *tm* time that will call *callback* from the
within the :meth:`run` function. Returns a handle that may be passed to
:meth:`remove_alarm`.
:param tm: time to call callback e.g. ``time.time() + 5``
:type tm: float
:param callback: function to call with two parameters: this main loop
object and *user_data*
:type callback: callable
"""
def cb():
callback(self, user_data)
return self.event_loop.alarm(tm - time.time(), cb)
def remove_alarm(self, handle):
"""
Remove an alarm. Return ``True`` if *handle* was found, ``False``
otherwise.
"""
return self.event_loop.remove_alarm(handle)
def watch_pipe(self, callback):
"""
Create a pipe for use by a subprocess or thread to trigger a callback
in the process/thread running the main loop.
:param callback: function taking one parameter to call from within
the process/thread running the main loop
:type callback: callable
This method returns a file descriptor attached to the write end of a
pipe. The read end of the pipe is added to the list of files
:attr:`event_loop` is watching. When data is written to the pipe the
callback function will be called and passed a single value containing
data read from the pipe.
This method may be used any time you want to update widgets from
another thread or subprocess.
Data may be written to the returned file descriptor with
``os.write(fd, data)``. Ensure that data is less than 512 bytes (or 4K
on Linux) so that the callback will be triggered just once with the
complete value of data passed in.
If the callback returns ``False`` then the watch will be removed from
:attr:`event_loop` and the read end of the pipe will be closed. You
are responsible for closing the write end of the pipe with
``os.close(fd)``.
"""
pipe_rd, pipe_wr = os.pipe()
fcntl.fcntl(pipe_rd, fcntl.F_SETFL, os.O_NONBLOCK)
watch_handle = None
def cb():
data = os.read(pipe_rd, PIPE_BUFFER_READ_SIZE)
rval = callback(data)
if rval is False:
self.event_loop.remove_watch_file(watch_handle)
os.close(pipe_rd)
watch_handle = self.event_loop.watch_file(pipe_rd, cb)
self._watch_pipes[pipe_wr] = (watch_handle, pipe_rd)
return pipe_wr
def remove_watch_pipe(self, write_fd):
"""
Close the read end of the pipe and remove the watch created by
:meth:`watch_pipe`. You are responsible for closing the write end of
the pipe.
Returns ``True`` if the watch pipe exists, ``False`` otherwise
"""
try:
watch_handle, pipe_rd = self._watch_pipes.pop(write_fd)
except KeyError:
return False
if not self.event_loop.remove_watch_file(watch_handle):
return False
os.close(pipe_rd)
return True
def watch_file(self, fd, callback):
"""
Call *callback* when *fd* has some data to read. No parameters are
passed to callback.
Returns a handle that may be passed to :meth:`remove_watch_file`.
"""
return self.event_loop.watch_file(fd, callback)
def remove_watch_file(self, handle):
"""
Remove a watch file. Returns ``True`` if the watch file
exists, ``False`` otherwise.
"""
return self.event_loop.remove_watch_file(handle)
def run(self):
"""
Start the main loop handling input events and updating the screen. The
loop will continue until an :exc:`ExitMainLoop` exception is raised.
This method will use :attr:`screen`'s run_wrapper() method if
:attr:`screen`'s start() method has not already been called.
"""
try:
if self.screen.started:
self._run()
else:
self.screen.run_wrapper(self._run)
except ExitMainLoop:
pass
def _test_run(self):
"""
>>> w = _refl("widget") # _refl prints out function calls
>>> w.render_rval = "fake canvas" # *_rval is used for return values
>>> scr = _refl("screen")
>>> scr.get_input_descriptors_rval = [42]
>>> scr.get_cols_rows_rval = (20, 10)
>>> scr.started = True
>>> scr._urwid_signals = {}
>>> evl = _refl("event_loop")
>>> evl.enter_idle_rval = 1
>>> evl.watch_file_rval = 2
>>> ml = MainLoop(w, [], scr, event_loop=evl)
>>> ml.run() # doctest:+ELLIPSIS
screen.set_mouse_tracking()
screen.get_cols_rows()
widget.render((20, 10), focus=True)
screen.draw_screen((20, 10), 'fake canvas')
screen.get_input_descriptors()
event_loop.watch_file(42, <bound method ...>)
event_loop.enter_idle(<bound method ...>)
event_loop.run()
event_loop.remove_enter_idle(1)
event_loop.remove_watch_file(2)
>>> scr.started = False
>>> ml.run() # doctest:+ELLIPSIS
screen.run_wrapper(<bound method ...>)
"""
def _run(self):
if self.handle_mouse:
self.screen.set_mouse_tracking()
if not hasattr(self.screen, 'get_input_descriptors'):
return self._run_screen_event_loop()
self.draw_screen()
fd_handles = []
def reset_input_descriptors(only_remove=False):
for handle in fd_handles:
self.event_loop.remove_watch_file(handle)
if only_remove:
del fd_handles[:]
else:
fd_handles[:] = [
self.event_loop.watch_file(fd, self._update)
for fd in self.screen.get_input_descriptors()]
if not fd_handles and self._input_timeout is not None:
self.event_loop.remove_alarm(self._input_timeout)
try:
signals.connect_signal(self.screen, INPUT_DESCRIPTORS_CHANGED,
reset_input_descriptors)
except NameError:
pass
# watch our input descriptors
reset_input_descriptors()
idle_handle = self.event_loop.enter_idle(self.entering_idle)
# Go..
self.event_loop.run()
# tidy up
self.event_loop.remove_enter_idle(idle_handle)
reset_input_descriptors(True)
signals.disconnect_signal(self.screen, INPUT_DESCRIPTORS_CHANGED,
reset_input_descriptors)
def _update(self, timeout=False):
"""
>>> w = _refl("widget")
>>> w.selectable_rval = True
>>> w.mouse_event_rval = True
>>> scr = _refl("screen")
>>> scr.get_cols_rows_rval = (15, 5)
>>> scr.get_input_nonblocking_rval = 1, ['y'], [121]
>>> evl = _refl("event_loop")
>>> ml = MainLoop(w, [], scr, event_loop=evl)
>>> ml._input_timeout = "old timeout"
>>> ml._update() # doctest:+ELLIPSIS
event_loop.remove_alarm('old timeout')
screen.get_input_nonblocking()
event_loop.alarm(1, <function ...>)
screen.get_cols_rows()
widget.selectable()
widget.keypress((15, 5), 'y')
>>> scr.get_input_nonblocking_rval = None, [("mouse press", 1, 5, 4)
... ], []
>>> ml._update()
screen.get_input_nonblocking()
widget.mouse_event((15, 5), 'mouse press', 1, 5, 4, focus=True)
>>> scr.get_input_nonblocking_rval = None, [], []
>>> ml._update()
screen.get_input_nonblocking()
"""
if self._input_timeout is not None and not timeout:
# cancel the timeout, something else triggered the update
self.event_loop.remove_alarm(self._input_timeout)
self._input_timeout = None
max_wait, keys, raw = self.screen.get_input_nonblocking()
if max_wait is not None:
# if get_input_nonblocking wants to be called back
# make sure it happens with an alarm
self._input_timeout = self.event_loop.alarm(max_wait,
lambda: self._update(timeout=True))
keys = self.input_filter(keys, raw)
if keys:
self.process_input(keys)
if 'window resize' in keys:
self.screen_size = None
def _run_screen_event_loop(self):
"""
This method is used when the screen does not support using
external event loops.
The alarms stored in the SelectEventLoop in :attr:`event_loop`
are modified by this method.
"""
next_alarm = None
while True:
self.draw_screen()
if not next_alarm and self.event_loop._alarms:
next_alarm = heapq.heappop(self.event_loop._alarms)
keys = None
while not keys:
if next_alarm:
sec = max(0, next_alarm[0] - time.time())
self.screen.set_input_timeouts(sec)
else:
self.screen.set_input_timeouts(None)
keys, raw = self.screen.get_input(True)
if not keys and next_alarm:
sec = next_alarm[0] - time.time()
if sec <= 0:
break
keys = self.input_filter(keys, raw)
if keys:
self.process_input(keys)
while next_alarm:
sec = next_alarm[0] - time.time()
if sec > 0:
break
tm, callback = next_alarm
callback()
if self.event_loop._alarms:
next_alarm = heapq.heappop(self.event_loop._alarms)
else:
next_alarm = None
if 'window resize' in keys:
self.screen_size = None
def _test_run_screen_event_loop(self):
"""
>>> w = _refl("widget")
>>> scr = _refl("screen")
>>> scr.get_cols_rows_rval = (10, 5)
>>> scr.get_input_rval = [], []
>>> ml = MainLoop(w, screen=scr)
>>> def stop_now(loop, data):
... raise ExitMainLoop()
>>> handle = ml.set_alarm_in(0, stop_now)
>>> try:
... ml._run_screen_event_loop()
... except ExitMainLoop:
... pass
screen.get_cols_rows()
widget.render((10, 5), focus=True)
screen.draw_screen((10, 5), None)
screen.set_input_timeouts(0)
screen.get_input(True)
"""
def process_input(self, keys):
"""
This method will pass keyboard input and mouse events to :attr:`widget`.
This method is called automatically from the :meth:`run` method when
there is input, but may also be called to simulate input from the user.
*keys* is a list of input returned from :attr:`screen`'s get_input()
or get_input_nonblocking() methods.
Returns ``True`` if any key was handled by a widget or the
:meth:`unhandled_input` method.
"""
if not self.screen_size:
self.screen_size = self.screen.get_cols_rows()
something_handled = False
for k in keys:
if k == 'window resize':
continue
if is_mouse_event(k):
event, button, col, row = k
if self._topmost_widget.mouse_event(self.screen_size,
event, button, col, row, focus=True ):
k = None
elif self._topmost_widget.selectable():
k = self._topmost_widget.keypress(self.screen_size, k)
if k:
if command_map[k] == REDRAW_SCREEN:
self.screen.clear()
something_handled = True
else:
something_handled |= bool(self.unhandled_input(k))
else:
something_handled = True
return something_handled
def _test_process_input(self):
"""
>>> w = _refl("widget")
>>> w.selectable_rval = True
>>> scr = _refl("screen")
>>> scr.get_cols_rows_rval = (10, 5)
>>> ml = MainLoop(w, [], scr)
>>> ml.process_input(['enter', ('mouse drag', 1, 14, 20)])
screen.get_cols_rows()
widget.selectable()
widget.keypress((10, 5), 'enter')
widget.mouse_event((10, 5), 'mouse drag', 1, 14, 20, focus=True)
True
"""
def input_filter(self, keys, raw):
"""
This function is passed each all the input events and raw keystroke
values. These values are passed to the *input_filter* function
passed to the constructor. That function must return a list of keys to
be passed to the widgets to handle. If no *input_filter* was
defined this implementation will return all the input events.
"""
if self._input_filter:
return self._input_filter(keys, raw)
return keys
def unhandled_input(self, input):
"""
This function is called with any input that was not handled by the
widgets, and calls the *unhandled_input* function passed to the
constructor. If no *unhandled_input* was defined then the input
will be ignored.
*input* is the keyboard or mouse input.
The *unhandled_input* function should return ``True`` if it handled
the input.
"""
if self._unhandled_input:
return self._unhandled_input(input)
def entering_idle(self):
"""
This method is called whenever the event loop is about to enter the
idle state. :meth:`draw_screen` is called here to update the
screen when anything has changed.
"""
if self.screen.started:
self.draw_screen()
def draw_screen(self):
"""
Render the widgets and paint the screen. This method is called
automatically from :meth:`entering_idle`.
If you modify the widgets displayed outside of handling input or
responding to an alarm you will need to call this method yourself
to repaint the screen.
"""
if not self.screen_size:
self.screen_size = self.screen.get_cols_rows()
canvas = self._topmost_widget.render(self.screen_size, focus=True)
self.screen.draw_screen(self.screen_size, canvas)
class MainLoop(object):
def __init__(self, widget, palette=[], screen=None,
handle_mouse=True, input_filter=None, unhandled_input=None,
event_loop=None, pop_ups=False):
"""
Simple main loop implementation.
widget -- topmost widget used for painting the screen,
stored as self.widget and may be modified
palette -- initial palette for screen
screen -- screen object or None to use raw_display.Screen,
stored as self.screen
handle_mouse -- True to process mouse events, passed to
self.screen
input_filter -- a function to filter input before sending
it to self.widget, called from self.input_filter
unhandled_input -- a function called when input is not
handled by self.widget, called from self.unhandled_input
event_loop -- if screen supports external an event loop it
may be given here, or leave as None to use
SelectEventLoop, stored as self.event_loop
pop_ups -- True to wrap self.widget with a PopUpTarget
instance to allow any widget to open a pop-up anywhere on
the screen
This is the standard main loop implementation with a single
screen.
The widget passed must be a box widget.
"""
self._widget = widget
self.handle_mouse = handle_mouse
self.pop_ups = pop_ups # triggers property setting side-effect
if not screen:
from urwid import raw_display
screen = raw_display.Screen()
if palette:
screen.register_palette(palette)
self.screen = screen
self.screen_size = None
self._unhandled_input = unhandled_input
self._input_filter = input_filter
if not hasattr(screen, 'get_input_descriptors'
) and event_loop is not None:
raise NotImplementedError("screen object passed "
"%r does not support external event loops" % (screen,))
if event_loop is None:
event_loop = SelectEventLoop()
self.event_loop = event_loop
self._input_timeout = None
self._watch_pipes = {}
def _set_widget(self, widget):
self._widget = widget
if self.pop_ups:
self._topmost_widget.original_widget = self._widget
else:
self._topmost_widget = self._widget
widget = property(lambda self:self._widget, _set_widget)
def _set_pop_ups(self, pop_ups):
self._pop_ups = pop_ups
if pop_ups:
self._topmost_widget = PopUpTarget(self._widget)
else:
self._topmost_widget = self._widget
pop_ups = property(lambda self:self._pop_ups, _set_pop_ups)
def set_alarm_in(self, sec, callback, user_data=None):
"""
Schedule an alarm in sec seconds that will call
callback(main_loop, user_data) from the within the run()
function.
sec -- floating point seconds until alarm
callback -- callback(main_loop, user_data) callback function
user_data -- object to pass to callback
"""
def cb():
callback(self, user_data)
return self.event_loop.alarm(sec, cb)
def set_alarm_at(self, tm, callback, user_data=None):
"""
Schedule at tm time that will call
callback(main_loop, user_data) from the within the run()
function.
Returns a handle that may be passed to remove_alarm()
tm -- floating point local time of alarm
callback -- callback(main_loop, user_data) callback function
user_data -- object to pass to callback
"""
def cb():
callback(self, user_data)
return self.event_loop.alarm(tm - time.time(), cb)
def remove_alarm(self, handle):
"""
Remove an alarm.
Return True if the handle was found, False otherwise.
"""
return self.event_loop.remove_alarm(handle)
def watch_pipe(self, callback):
"""
Create a pipe for use by a subprocess or thread to trigger
a callback in the process/thread running the MainLoop.
callback -- function to call MainLoop.run thread/process
This function returns a file descriptor attached to the
write end of a pipe. The read end of the pipe is added to
the list of files the event loop is watching. When
data is written to the pipe the callback function will be
called and passed a single value containing data read.
This method should be used any time you want to update
widgets from another thread or subprocess.
Data may be written to the returned file descriptor with
os.write(fd, data). Ensure that data is less than 512
bytes (or 4K on Linux) so that the callback will be
triggered just once with the complete value of data
passed in.
If the callback returns False then the watch will be
removed and the read end of the pipe will be closed.
You are responsible for closing the write end of the pipe.
"""
pipe_rd, pipe_wr = os.pipe()
fcntl.fcntl(pipe_rd, fcntl.F_SETFL, os.O_NONBLOCK)
watch_handle = None
def cb():
data = os.read(pipe_rd, PIPE_BUFFER_READ_SIZE)
rval = callback(data)
if rval is False:
self.event_loop.remove_watch_file(watch_handle)
os.close(pipe_rd)
watch_handle = self.event_loop.watch_file(pipe_rd, cb)
self._watch_pipes[pipe_wr] = (watch_handle, pipe_rd)
return pipe_wr
def remove_watch_pipe(self, write_fd):
"""
Close the read end of the pipe and remove the watch created
by watch_pipe(). You are responsible for closing the write
end of the pipe.
Returns True if the watch pipe exists, False otherwise
"""
try:
watch_handle, pipe_rd = self._watch_pipes.pop(write_fd)
except KeyError:
return False
if not self.event_loop.remove_watch_file(watch_handle):
return False
os.close(pipe_rd)
return True
def watch_file(self, fd, callback):
"""
Call callback() when fd has some data to read. No parameters
are passed to callback.
Returns a handle that may be passed to remove_watch_file()
fd -- file descriptor to watch for input
callback -- function to call when input is available
"""
return self.event_loop.watch_file(fd, callback)
def remove_watch_file(self, handle):
"""
Remove a watch file.
Returns True if the watch file exists, False otherwise.
"""
return self.event_loop.remove_watch_file(handle)
def run(self):
"""
Start the main loop handling input events and updating
the screen. The loop will continue until an ExitMainLoop
exception is raised.
This function will call screen.run_wrapper() if screen.start()
has not already been called.
>>> w = _refl("widget") # _refl prints out function calls
>>> w.render_rval = "fake canvas" # *_rval is used for return values
>>> scr = _refl("screen")
>>> scr.get_input_descriptors_rval = [42]
>>> scr.get_cols_rows_rval = (20, 10)
>>> scr.started = True
>>> scr._urwid_signals = {}
>>> evl = _refl("event_loop")
>>> evl.enter_idle_rval = 1
>>> evl.watch_file_rval = 2
>>> ml = MainLoop(w, [], scr, event_loop=evl)
>>> ml.run() # doctest:+ELLIPSIS
screen.set_mouse_tracking()
screen.get_cols_rows()
widget.render((20, 10), focus=True)
screen.draw_screen((20, 10), 'fake canvas')
screen.get_input_descriptors()
event_loop.watch_file(42, <bound method ...>)
event_loop.enter_idle(<bound method ...>)
event_loop.run()
event_loop.remove_enter_idle(1)
event_loop.remove_watch_file(2)
>>> scr.started = False
>>> ml.run() # doctest:+ELLIPSIS
screen.run_wrapper(<bound method ...>)
"""
try:
if self.screen.started:
self._run()
else:
self.screen.run_wrapper(self._run)
except ExitMainLoop:
pass
def _run(self):
if self.handle_mouse:
self.screen.set_mouse_tracking()
if not hasattr(self.screen, 'get_input_descriptors'):
return self._run_screen_event_loop()
self.draw_screen()
fd_handles = []
def reset_input_descriptors(only_remove=False):
for handle in fd_handles:
self.event_loop.remove_watch_file(handle)
if only_remove:
return
fd_handles[:] = [
self.event_loop.watch_file(fd, self._update)
for fd in self.screen.get_input_descriptors()]
try:
signals.connect_signal(self.screen, INPUT_DESCRIPTORS_CHANGED,
reset_input_descriptors)
except NameError:
pass
# watch our input descriptors
reset_input_descriptors()
idle_handle = self.event_loop.enter_idle(self.entering_idle)
# Go..
self.event_loop.run()
# tidy up
self.event_loop.remove_enter_idle(idle_handle)
reset_input_descriptors(True)
signals.disconnect_signal(self.screen, INPUT_DESCRIPTORS_CHANGED,
reset_input_descriptors)
def _update(self, timeout=False):
"""
>>> w = _refl("widget")
>>> w.selectable_rval = True
>>> w.mouse_event_rval = True
>>> scr = _refl("screen")
>>> scr.get_cols_rows_rval = (15, 5)
>>> scr.get_input_nonblocking_rval = 1, ['y'], [121]
>>> evl = _refl("event_loop")
>>> ml = MainLoop(w, [], scr, event_loop=evl)
>>> ml._input_timeout = "old timeout"
>>> ml._update() # doctest:+ELLIPSIS
event_loop.remove_alarm('old timeout')
screen.get_input_nonblocking()
event_loop.alarm(1, <function ...>)
screen.get_cols_rows()
widget.selectable()
widget.keypress((15, 5), 'y')
>>> scr.get_input_nonblocking_rval = None, [("mouse press", 1, 5, 4)
... ], []
>>> ml._update()
screen.get_input_nonblocking()
widget.mouse_event((15, 5), 'mouse press', 1, 5, 4, focus=True)
>>> scr.get_input_nonblocking_rval = None, [], []
>>> ml._update()
screen.get_input_nonblocking()
"""
if self._input_timeout is not None and not timeout:
# cancel the timeout, something else triggered the update
self.event_loop.remove_alarm(self._input_timeout)
self._input_timeout = None
max_wait, keys, raw = self.screen.get_input_nonblocking()
if max_wait is not None:
# if get_input_nonblocking wants to be called back
# make sure it happens with an alarm
self._input_timeout = self.event_loop.alarm(max_wait,
lambda: self._update(timeout=True))
keys = self.input_filter(keys, raw)
if keys:
self.process_input(keys)
if 'window resize' in keys:
self.screen_size = None
def _run_screen_event_loop(self):
"""
This method is used when the screen does not support using
external event loops.
The alarms stored in the SelectEventLoop in self.event_loop
are modified by this method.
"""
next_alarm = None
while True:
self.draw_screen()
if not next_alarm and self.event_loop._alarms:
next_alarm = heapq.heappop(self.event_loop._alarms)
keys = None
while not keys:
if next_alarm:
sec = max(0, next_alarm[0] - time.time())
self.screen.set_input_timeouts(sec)
else:
self.screen.set_input_timeouts(None)
keys, raw = self.screen.get_input(True)
if not keys and next_alarm:
sec = next_alarm[0] - time.time()
if sec <= 0:
break
keys = self.input_filter(keys, raw)
if keys:
self.process_input(keys)
while next_alarm:
sec = next_alarm[0] - time.time()
if sec > 0:
break
tm, callback, user_data = next_alarm
callback(self, user_data)
if self._alarms:
next_alarm = heapq.heappop(self.event_loop._alarms)
else:
next_alarm = None
if 'window resize' in keys:
self.screen_size = None
def process_input(self, keys):
"""
This function will pass keyboard input and mouse events
to self.widget. This function is called automatically
from the run() method when there is input, but may also be
called to simulate input from the user.
keys -- list of input returned from self.screen.get_input()
Returns True if any key was handled by a widget or the
unhandled_input() method.
>>> w = _refl("widget")
>>> w.selectable_rval = True
>>> scr = _refl("screen")
>>> scr.get_cols_rows_rval = (10, 5)
>>> ml = MainLoop(w, [], scr)
>>> ml.process_input(['enter', ('mouse drag', 1, 14, 20)])
screen.get_cols_rows()
widget.selectable()
widget.keypress((10, 5), 'enter')
widget.mouse_event((10, 5), 'mouse drag', 1, 14, 20, focus=True)
True
"""
if not self.screen_size:
self.screen_size = self.screen.get_cols_rows()
something_handled = False
for k in keys:
if k == 'window resize':
continue
if is_mouse_event(k):
event, button, col, row = k
if self._topmost_widget.mouse_event(self.screen_size,
event, button, col, row, focus=True ):
k = None
elif self._topmost_widget.selectable():
k = self._topmost_widget.keypress(self.screen_size, k)
if k:
if command_map[k] == 'redraw screen':
self.screen.clear()
something_handled = True
else:
something_handled |= bool(self.unhandled_input(k))
else:
something_handled = True
return something_handled
def input_filter(self, keys, raw):
"""
This function is passed each all the input events and raw
keystroke values. These values are passed to the
input_filter function passed to the constructor. That
function must return a list of keys to be passed to the
widgets to handle. If no input_filter was defined this
implementation will return all the input events.
input -- keyboard or mouse input
"""
if self._input_filter:
return self._input_filter(keys, raw)
return keys
def unhandled_input(self, input):
"""
This function is called with any input that was not handled
by the widgets, and calls the unhandled_input function passed
to the constructor. If no unhandled_input was defined then
the input will be ignored.
input -- keyboard or mouse input
The unhandled_input method should return True if it handled
the input.
"""
if self._unhandled_input:
return self._unhandled_input(input)
def entering_idle(self):
"""
This function is called whenever the event loop is about
to enter the idle state. self.draw_screen() is called here
to update the screen if anything has changed.
"""
if self.screen.started:
self.draw_screen()
def draw_screen(self):
"""
Render the widgets and paint the screen. This function is
called automatically from run() but may be called additional
times if repainting is required without also processing input.
"""
if not self.screen_size:
self.screen_size = self.screen.get_cols_rows()
canvas = self._topmost_widget.render(self.screen_size, focus=True)
self.screen.draw_screen(self.screen_size, canvas)
class MainLoop(object):
"""
This is the standard main loop implementation for a single interactive
session.
:param widget: the topmost widget used for painting the screen, stored as
:attr:`widget` and may be modified. Must be a box widget.
:type widget: widget instance
:param palette: initial palette for screen
:type palette: iterable of palette entries
:param screen: screen to use, default is a new :class:`raw_display.Screen`
instance; stored as :attr:`screen`
:type screen: display module screen instance
:param handle_mouse: ``True`` to ask :attr:`.screen` to process mouse events
:type handle_mouse: bool
:param input_filter: a function to filter input before sending it to
:attr:`.widget`, called from :meth:`.input_filter`
:type input_filter: callable
:param unhandled_input: a function called when input is not handled by
:attr:`.widget`, called from :meth:`.unhandled_input`
:type unhandled_input: callable
:param event_loop: if :attr:`.screen` supports external an event loop it may be
given here, default is a new :class:`SelectEventLoop` instance;
stored as :attr:`.event_loop`
:type event_loop: event loop instance
:param pop_ups: `True` to wrap :attr:`.widget` with a :class:`PopUpTarget`
instance to allow any widget to open a pop-up anywhere on the screen
:type pop_ups: boolean
.. attribute:: screen
The screen object this main loop uses for screen updates and reading input
.. attribute:: event_loop
The event loop object this main loop uses for waiting on alarms and IO
"""
def __init__(self,
widget,
palette=(),
screen=None,
handle_mouse=True,
input_filter=None,
unhandled_input=None,
event_loop=None,
pop_ups=False):
self._widget = widget
self.handle_mouse = handle_mouse
self.pop_ups = pop_ups # triggers property setting side-effect
if not screen:
from urwid import raw_display
screen = raw_display.Screen()
if palette:
screen.register_palette(palette)
self.screen = screen
self.screen_size = None
self._unhandled_input = unhandled_input
self._input_filter = input_filter
if not hasattr(screen,
'get_input_descriptors') and event_loop is not None:
raise NotImplementedError(
"screen object passed "
"%r does not support external event loops" % (screen, ))
if event_loop is None:
event_loop = SelectEventLoop()
self.event_loop = event_loop
self._input_timeout = None
self._watch_pipes = {}
def _set_widget(self, widget):
self._widget = widget
if self.pop_ups:
self._topmost_widget.original_widget = self._widget
else:
self._topmost_widget = self._widget
widget = property(lambda self: self._widget,
_set_widget,
doc="""
Property for the topmost widget used to draw the screen.
This must be a box widget.
""")
def _set_pop_ups(self, pop_ups):
self._pop_ups = pop_ups
if pop_ups:
self._topmost_widget = PopUpTarget(self._widget)
else:
self._topmost_widget = self._widget
pop_ups = property(lambda self: self._pop_ups, _set_pop_ups)
def set_alarm_in(self, sec, callback, user_data=None):
"""
Schedule an alarm in *sec* seconds that will call *callback* from the
within the :meth:`run` method.
:param sec: seconds until alarm
:type sec: float
:param callback: function to call with two parameters: this main loop
object and *user_data*
:type callback: callable
"""
def cb():
callback(self, user_data)
return self.event_loop.alarm(sec, cb)
def set_alarm_at(self, tm, callback, user_data=None):
"""
Schedule an alarm at *tm* time that will call *callback* from the
within the :meth:`run` function. Returns a handle that may be passed to
:meth:`remove_alarm`.
:param tm: time to call callback e.g. ``time.time() + 5``
:type tm: float
:param callback: function to call with two parameters: this main loop
object and *user_data*
:type callback: callable
"""
def cb():
callback(self, user_data)
return self.event_loop.alarm(tm - time.time(), cb)
def remove_alarm(self, handle):
"""
Remove an alarm. Return ``True`` if *handle* was found, ``False``
otherwise.
"""
return self.event_loop.remove_alarm(handle)
def watch_pipe(self, callback):
"""
Create a pipe for use by a subprocess or thread to trigger a callback
in the process/thread running the main loop.
:param callback: function taking one parameter to call from within
the process/thread running the main loop
:type callback: callable
This method returns a file descriptor attached to the write end of a
pipe. The read end of the pipe is added to the list of files
:attr:`event_loop` is watching. When data is written to the pipe the
callback function will be called and passed a single value containing
data read from the pipe.
This method may be used any time you want to update widgets from
another thread or subprocess.
Data may be written to the returned file descriptor with
``os.write(fd, data)``. Ensure that data is less than 512 bytes (or 4K
on Linux) so that the callback will be triggered just once with the
complete value of data passed in.
If the callback returns ``False`` then the watch will be removed from
:attr:`event_loop` and the read end of the pipe will be closed. You
are responsible for closing the write end of the pipe with
``os.close(fd)``.
"""
pipe_rd, pipe_wr = os.pipe()
fcntl.fcntl(pipe_rd, fcntl.F_SETFL, os.O_NONBLOCK)
watch_handle = None
def cb():
data = os.read(pipe_rd, PIPE_BUFFER_READ_SIZE)
rval = callback(data)
if rval is False:
self.event_loop.remove_watch_file(watch_handle)
os.close(pipe_rd)
watch_handle = self.event_loop.watch_file(pipe_rd, cb)
self._watch_pipes[pipe_wr] = (watch_handle, pipe_rd)
return pipe_wr
def remove_watch_pipe(self, write_fd):
"""
Close the read end of the pipe and remove the watch created by
:meth:`watch_pipe`. You are responsible for closing the write end of
the pipe.
Returns ``True`` if the watch pipe exists, ``False`` otherwise
"""
try:
watch_handle, pipe_rd = self._watch_pipes.pop(write_fd)
except KeyError:
return False
if not self.event_loop.remove_watch_file(watch_handle):
return False
os.close(pipe_rd)
return True
def watch_file(self, fd, callback):
"""
Call *callback* when *fd* has some data to read. No parameters are
passed to callback.
Returns a handle that may be passed to :meth:`remove_watch_file`.
"""
return self.event_loop.watch_file(fd, callback)
def remove_watch_file(self, handle):
"""
Remove a watch file. Returns ``True`` if the watch file
exists, ``False`` otherwise.
"""
return self.event_loop.remove_watch_file(handle)
def run(self):
"""
Start the main loop handling input events and updating the screen. The
loop will continue until an :exc:`ExitMainLoop` exception is raised.
This method will use :attr:`screen`'s run_wrapper() method if
:attr:`screen`'s start() method has not already been called.
"""
try:
if self.screen.started:
self._run()
else:
self.screen.run_wrapper(self._run)
except ExitMainLoop:
pass
def _test_run(self):
"""
>>> w = _refl("widget") # _refl prints out function calls
>>> w.render_rval = "fake canvas" # *_rval is used for return values
>>> scr = _refl("screen")
>>> scr.get_input_descriptors_rval = [42]
>>> scr.get_cols_rows_rval = (20, 10)
>>> scr.started = True
>>> scr._urwid_signals = {}
>>> evl = _refl("event_loop")
>>> evl.enter_idle_rval = 1
>>> evl.watch_file_rval = 2
>>> ml = MainLoop(w, [], scr, event_loop=evl)
>>> ml.run() # doctest:+ELLIPSIS
screen.set_mouse_tracking()
screen.get_cols_rows()
widget.render((20, 10), focus=True)
screen.draw_screen((20, 10), 'fake canvas')
screen.get_input_descriptors()
event_loop.watch_file(42, <bound method ...>)
event_loop.enter_idle(<bound method ...>)
event_loop.run()
event_loop.remove_enter_idle(1)
event_loop.remove_watch_file(2)
>>> scr.started = False
>>> ml.run() # doctest:+ELLIPSIS
screen.run_wrapper(<bound method ...>)
"""
def _run(self):
if self.handle_mouse:
self.screen.set_mouse_tracking()
if not hasattr(self.screen, 'get_input_descriptors'):
return self._run_screen_event_loop()
self.draw_screen()
fd_handles = []
def reset_input_descriptors(only_remove=False):
for handle in fd_handles:
self.event_loop.remove_watch_file(handle)
if only_remove:
del fd_handles[:]
else:
fd_handles[:] = [
self.event_loop.watch_file(fd, self._update)
for fd in self.screen.get_input_descriptors()
]
if not fd_handles and self._input_timeout is not None:
self.event_loop.remove_alarm(self._input_timeout)
try:
signals.connect_signal(self.screen, INPUT_DESCRIPTORS_CHANGED,
reset_input_descriptors)
except NameError:
pass
# watch our input descriptors
reset_input_descriptors()
idle_handle = self.event_loop.enter_idle(self.entering_idle)
# Go..
self.event_loop.run()
# tidy up
self.event_loop.remove_enter_idle(idle_handle)
reset_input_descriptors(True)
signals.disconnect_signal(self.screen, INPUT_DESCRIPTORS_CHANGED,
reset_input_descriptors)
def _update(self, timeout=False):
"""
>>> w = _refl("widget")
>>> w.selectable_rval = True
>>> w.mouse_event_rval = True
>>> scr = _refl("screen")
>>> scr.get_cols_rows_rval = (15, 5)
>>> scr.get_input_nonblocking_rval = 1, ['y'], [121]
>>> evl = _refl("event_loop")
>>> ml = MainLoop(w, [], scr, event_loop=evl)
>>> ml._input_timeout = "old timeout"
>>> ml._update() # doctest:+ELLIPSIS
event_loop.remove_alarm('old timeout')
screen.get_input_nonblocking()
event_loop.alarm(1, <function ...>)
screen.get_cols_rows()
widget.selectable()
widget.keypress((15, 5), 'y')
>>> scr.get_input_nonblocking_rval = None, [("mouse press", 1, 5, 4)
... ], []
>>> ml._update()
screen.get_input_nonblocking()
widget.mouse_event((15, 5), 'mouse press', 1, 5, 4, focus=True)
>>> scr.get_input_nonblocking_rval = None, [], []
>>> ml._update()
screen.get_input_nonblocking()
"""
if self._input_timeout is not None and not timeout:
# cancel the timeout, something else triggered the update
self.event_loop.remove_alarm(self._input_timeout)
self._input_timeout = None
max_wait, keys, raw = self.screen.get_input_nonblocking()
if max_wait is not None:
# if get_input_nonblocking wants to be called back
# make sure it happens with an alarm
self._input_timeout = self.event_loop.alarm(
max_wait, lambda: self._update(timeout=True))
keys = self.input_filter(keys, raw)
if keys:
self.process_input(keys)
if 'window resize' in keys:
self.screen_size = None
def _run_screen_event_loop(self):
"""
This method is used when the screen does not support using
external event loops.
The alarms stored in the SelectEventLoop in :attr:`event_loop`
are modified by this method.
"""
next_alarm = None
while True:
self.draw_screen()
if not next_alarm and self.event_loop._alarms:
next_alarm = heapq.heappop(self.event_loop._alarms)
keys = None
while not keys:
if next_alarm:
sec = max(0, next_alarm[0] - time.time())
self.screen.set_input_timeouts(sec)
else:
self.screen.set_input_timeouts(None)
keys, raw = self.screen.get_input(True)
if not keys and next_alarm:
sec = next_alarm[0] - time.time()
if sec <= 0:
break
keys = self.input_filter(keys, raw)
if keys:
self.process_input(keys)
while next_alarm:
sec = next_alarm[0] - time.time()
if sec > 0:
break
tm, callback = next_alarm
callback()
if self.event_loop._alarms:
next_alarm = heapq.heappop(self.event_loop._alarms)
else:
next_alarm = None
if 'window resize' in keys:
self.screen_size = None
def _test_run_screen_event_loop(self):
"""
>>> w = _refl("widget")
>>> scr = _refl("screen")
>>> scr.get_cols_rows_rval = (10, 5)
>>> scr.get_input_rval = [], []
>>> ml = MainLoop(w, screen=scr)
>>> def stop_now(loop, data):
... raise ExitMainLoop()
>>> handle = ml.set_alarm_in(0, stop_now)
>>> try:
... ml._run_screen_event_loop()
... except ExitMainLoop:
... pass
screen.get_cols_rows()
widget.render((10, 5), focus=True)
screen.draw_screen((10, 5), None)
screen.set_input_timeouts(0)
screen.get_input(True)
"""
def process_input(self, keys):
"""
This method will pass keyboard input and mouse events to :attr:`widget`.
This method is called automatically from the :meth:`run` method when
there is input, but may also be called to simulate input from the user.
*keys* is a list of input returned from :attr:`screen`'s get_input()
or get_input_nonblocking() methods.
Returns ``True`` if any key was handled by a widget or the
:meth:`unhandled_input` method.
"""
if not self.screen_size:
self.screen_size = self.screen.get_cols_rows()
something_handled = False
for k in keys:
if k == 'window resize':
continue
if is_mouse_event(k):
event, button, col, row = k
if self._topmost_widget.mouse_event(self.screen_size,
event,
button,
col,
row,
focus=True):
k = None
elif self._topmost_widget.selectable():
k = self._topmost_widget.keypress(self.screen_size, k)
if k:
if command_map[k] == REDRAW_SCREEN:
self.screen.clear()
something_handled = True
else:
something_handled |= bool(self.unhandled_input(k))
else:
something_handled = True
return something_handled
def _test_process_input(self):
"""
>>> w = _refl("widget")
>>> w.selectable_rval = True
>>> scr = _refl("screen")
>>> scr.get_cols_rows_rval = (10, 5)
>>> ml = MainLoop(w, [], scr)
>>> ml.process_input(['enter', ('mouse drag', 1, 14, 20)])
screen.get_cols_rows()
widget.selectable()
widget.keypress((10, 5), 'enter')
widget.mouse_event((10, 5), 'mouse drag', 1, 14, 20, focus=True)
True
"""
def input_filter(self, keys, raw):
"""
This function is passed each all the input events and raw keystroke
values. These values are passed to the *input_filter* function
passed to the constructor. That function must return a list of keys to
be passed to the widgets to handle. If no *input_filter* was
defined this implementation will return all the input events.
"""
if self._input_filter:
return self._input_filter(keys, raw)
return keys
def unhandled_input(self, input):
"""
This function is called with any input that was not handled by the
widgets, and calls the *unhandled_input* function passed to the
constructor. If no *unhandled_input* was defined then the input
will be ignored.
*input* is the keyboard or mouse input.
The *unhandled_input* function should return ``True`` if it handled
the input.
"""
if self._unhandled_input:
return self._unhandled_input(input)
def entering_idle(self):
"""
This method is called whenever the event loop is about to enter the
idle state. :meth:`draw_screen` is called here to update the
screen when anything has changed.
"""
if self.screen.started:
self.draw_screen()
def draw_screen(self):
"""
Render the widgets and paint the screen. This method is called
automatically from :meth:`entering_idle`.
If you modify the widgets displayed outside of handling input or
responding to an alarm you will need to call this method yourself
to repaint the screen.
"""
if not self.screen_size:
self.screen_size = self.screen.get_cols_rows()
canvas = self._topmost_widget.render(self.screen_size, focus=True)
self.screen.draw_screen(self.screen_size, canvas)
class MainLoop(object):
def __init__(self,
widget,
palette=[],
screen=None,
handle_mouse=True,
input_filter=None,
unhandled_input=None,
event_loop=None,
pop_ups=False):
"""
Simple main loop implementation.
widget -- topmost widget used for painting the screen,
stored as self.widget and may be modified
palette -- initial palette for screen
screen -- screen object or None to use raw_display.Screen,
stored as self.screen
handle_mouse -- True to process mouse events, passed to
self.screen
input_filter -- a function to filter input before sending
it to self.widget, called from self.input_filter
unhandled_input -- a function called when input is not
handled by self.widget, called from self.unhandled_input
event_loop -- if screen supports external an event loop it
may be given here, or leave as None to use
SelectEventLoop, stored as self.event_loop
pop_ups -- True to wrap self.widget with a PopUpTarget
instance to allow any widget to open a pop-up anywhere on
the screen
This is the standard main loop implementation with a single
screen.
The widget passed must be a box widget.
"""
self._widget = widget
self.handle_mouse = handle_mouse
self.pop_ups = pop_ups # triggers property setting side-effect
if not screen:
from urwid import raw_display
screen = raw_display.Screen()
if palette:
screen.register_palette(palette)
self.screen = screen
self.screen_size = None
self._unhandled_input = unhandled_input
self._input_filter = input_filter
if not hasattr(screen,
'get_input_descriptors') and event_loop is not None:
raise NotImplementedError(
"screen object passed "
"%r does not support external event loops" % (screen, ))
if event_loop is None:
event_loop = SelectEventLoop()
self.event_loop = event_loop
self._input_timeout = None
self._watch_pipes = {}
def _set_widget(self, widget):
self._widget = widget
if self.pop_ups:
self._topmost_widget.original_widget = self._widget
else:
self._topmost_widget = self._widget
widget = property(lambda self: self._widget, _set_widget)
def _set_pop_ups(self, pop_ups):
self._pop_ups = pop_ups
if pop_ups:
self._topmost_widget = PopUpTarget(self._widget)
else:
self._topmost_widget = self._widget
pop_ups = property(lambda self: self._pop_ups, _set_pop_ups)
def set_alarm_in(self, sec, callback, user_data=None):
"""
Schedule an alarm in sec seconds that will call
callback(main_loop, user_data) from the within the run()
function.
sec -- floating point seconds until alarm
callback -- callback(main_loop, user_data) callback function
user_data -- object to pass to callback
"""
def cb():
callback(self, user_data)
return self.event_loop.alarm(sec, cb)
def set_alarm_at(self, tm, callback, user_data=None):
"""
Schedule at tm time that will call
callback(main_loop, user_data) from the within the run()
function.
Returns a handle that may be passed to remove_alarm()
tm -- floating point local time of alarm
callback -- callback(main_loop, user_data) callback function
user_data -- object to pass to callback
"""
def cb():
callback(self, user_data)
return self.event_loop.alarm(tm - time.time(), cb)
def remove_alarm(self, handle):
"""
Remove an alarm.
Return True if the handle was found, False otherwise.
"""
return self.event_loop.remove_alarm(handle)
def watch_pipe(self, callback):
"""
Create a pipe for use by a subprocess or thread to trigger
a callback in the process/thread running the MainLoop.
callback -- function to call MainLoop.run thread/process
This function returns a file descriptor attached to the
write end of a pipe. The read end of the pipe is added to
the list of files the event loop is watching. When
data is written to the pipe the callback function will be
called and passed a single value containing data read.
This method should be used any time you want to update
widgets from another thread or subprocess.
Data may be written to the returned file descriptor with
os.write(fd, data). Ensure that data is less than 512
bytes (or 4K on Linux) so that the callback will be
triggered just once with the complete value of data
passed in.
If the callback returns False then the watch will be
removed and the read end of the pipe will be closed.
You are responsible for closing the write end of the pipe.
"""
pipe_rd, pipe_wr = os.pipe()
fcntl.fcntl(pipe_rd, fcntl.F_SETFL, os.O_NONBLOCK)
watch_handle = None
def cb():
data = os.read(pipe_rd, PIPE_BUFFER_READ_SIZE)
rval = callback(data)
if rval is False:
self.event_loop.remove_watch_file(watch_handle)
os.close(pipe_rd)
watch_handle = self.event_loop.watch_file(pipe_rd, cb)
self._watch_pipes[pipe_wr] = (watch_handle, pipe_rd)
return pipe_wr
def remove_watch_pipe(self, write_fd):
"""
Close the read end of the pipe and remove the watch created
by watch_pipe(). You are responsible for closing the write
end of the pipe.
Returns True if the watch pipe exists, False otherwise
"""
try:
watch_handle, pipe_rd = self._watch_pipes.remove(write_fd)
except KeyError:
return False
if not self.event_loop.remove_watch_file(watch_handle):
return False
os.close(pipe_rd)
return True
def watch_file(self, fd, callback):
"""
Call callback() when fd has some data to read. No parameters
are passed to callback.
Returns a handle that may be passed to remove_watch_file()
fd -- file descriptor to watch for input
callback -- function to call when input is available
"""
return self.event_loop.watch_file(fd, callback)
def remove_watch_file(self, handle):
"""
Remove a watch file.
Returns True if the watch file exists, False otherwise.
"""
return self.event_loop.remove_watch_file(handle)
def run(self):
"""
Start the main loop handling input events and updating
the screen. The loop will continue until an ExitMainLoop
exception is raised.
This function will call screen.run_wrapper() if screen.start()
has not already been called.
>>> w = _refl("widget") # _refl prints out function calls
>>> w.render_rval = "fake canvas" # *_rval is used for return values
>>> scr = _refl("screen")
>>> scr.get_input_descriptors_rval = [42]
>>> scr.get_cols_rows_rval = (20, 10)
>>> scr.started = True
>>> scr._urwid_signals = {}
>>> evl = _refl("event_loop")
>>> evl.enter_idle_rval = 1
>>> evl.watch_file_rval = 2
>>> ml = MainLoop(w, [], scr, event_loop=evl)
>>> ml.run() # doctest:+ELLIPSIS
screen.set_mouse_tracking()
screen.get_cols_rows()
widget.render((20, 10), focus=True)
screen.draw_screen((20, 10), 'fake canvas')
screen.get_input_descriptors()
event_loop.watch_file(42, <bound method ...>)
event_loop.enter_idle(<bound method ...>)
event_loop.run()
event_loop.remove_enter_idle(1)
event_loop.remove_watch_file(2)
>>> scr.started = False
>>> ml.run() # doctest:+ELLIPSIS
screen.run_wrapper(<bound method ...>)
"""
try:
if self.screen.started:
self._run()
else:
self.screen.run_wrapper(self._run)
except ExitMainLoop:
pass
def _run(self):
if self.handle_mouse:
self.screen.set_mouse_tracking()
if not hasattr(self.screen, 'get_input_descriptors'):
return self._run_screen_event_loop()
self.draw_screen()
fd_handles = []
def reset_input_descriptors(only_remove=False):
for handle in fd_handles:
self.event_loop.remove_watch_file(handle)
if only_remove:
return
fd_handles[:] = [
self.event_loop.watch_file(fd, self._update)
for fd in self.screen.get_input_descriptors()
]
try:
signals.connect_signal(self.screen, INPUT_DESCRIPTORS_CHANGED,
reset_input_descriptors)
except NameError:
pass
# watch our input descriptors
reset_input_descriptors()
idle_handle = self.event_loop.enter_idle(self.entering_idle)
# Go..
self.event_loop.run()
# tidy up
self.event_loop.remove_enter_idle(idle_handle)
reset_input_descriptors(True)
signals.disconnect_signal(self.screen, INPUT_DESCRIPTORS_CHANGED,
reset_input_descriptors)
def _update(self, timeout=False):
"""
>>> w = _refl("widget")
>>> w.selectable_rval = True
>>> w.mouse_event_rval = True
>>> scr = _refl("screen")
>>> scr.get_cols_rows_rval = (15, 5)
>>> scr.get_input_nonblocking_rval = 1, ['y'], [121]
>>> evl = _refl("event_loop")
>>> ml = MainLoop(w, [], scr, event_loop=evl)
>>> ml._input_timeout = "old timeout"
>>> ml._update() # doctest:+ELLIPSIS
event_loop.remove_alarm('old timeout')
screen.get_input_nonblocking()
event_loop.alarm(1, <function ...>)
screen.get_cols_rows()
widget.selectable()
widget.keypress((15, 5), 'y')
>>> scr.get_input_nonblocking_rval = None, [("mouse press", 1, 5, 4)
... ], []
>>> ml._update()
screen.get_input_nonblocking()
widget.mouse_event((15, 5), 'mouse press', 1, 5, 4, focus=True)
>>> scr.get_input_nonblocking_rval = None, [], []
>>> ml._update()
screen.get_input_nonblocking()
"""
if self._input_timeout is not None and not timeout:
# cancel the timeout, something else triggered the update
self.event_loop.remove_alarm(self._input_timeout)
self._input_timeout = None
max_wait, keys, raw = self.screen.get_input_nonblocking()
if max_wait is not None:
# if get_input_nonblocking wants to be called back
# make sure it happens with an alarm
self._input_timeout = self.event_loop.alarm(
max_wait, lambda: self._update(timeout=True))
keys = self.input_filter(keys, raw)
if keys:
self.process_input(keys)
if 'window resize' in keys:
self.screen_size = None
def _run_screen_event_loop(self):
"""
This method is used when the screen does not support using
external event loops.
The alarms stored in the SelectEventLoop in self.event_loop
are modified by this method.
"""
next_alarm = None
while True:
self.draw_screen()
if not next_alarm and self.event_loop._alarms:
next_alarm = heapq.heappop(self.event_loop._alarms)
keys = None
while not keys:
if next_alarm:
sec = max(0, next_alarm[0] - time.time())
self.screen.set_input_timeouts(sec)
else:
self.screen.set_input_timeouts(None)
keys, raw = self.screen.get_input(True)
if not keys and next_alarm:
sec = next_alarm[0] - time.time()
if sec <= 0:
break
keys = self.input_filter(keys, raw)
if keys:
self.process_input(keys)
while next_alarm:
sec = next_alarm[0] - time.time()
if sec > 0:
break
tm, callback, user_data = next_alarm
callback(self, user_data)
if self._alarms:
next_alarm = heapq.heappop(self.event_loop._alarms)
else:
next_alarm = None
if 'window resize' in keys:
self.screen_size = None
def process_input(self, keys):
"""
This function will pass keyboard input and mouse events
to self.widget. This function is called automatically
from the run() method when there is input, but may also be
called to simulate input from the user.
keys -- list of input returned from self.screen.get_input()
Returns True if any key was handled by a widget or the
unhandled_input() method.
>>> w = _refl("widget")
>>> w.selectable_rval = True
>>> scr = _refl("screen")
>>> scr.get_cols_rows_rval = (10, 5)
>>> ml = MainLoop(w, [], scr)
>>> ml.process_input(['enter', ('mouse drag', 1, 14, 20)])
screen.get_cols_rows()
widget.selectable()
widget.keypress((10, 5), 'enter')
widget.mouse_event((10, 5), 'mouse drag', 1, 14, 20, focus=True)
True
"""
if not self.screen_size:
self.screen_size = self.screen.get_cols_rows()
something_handled = False
for k in keys:
if is_mouse_event(k):
event, button, col, row = k
if self._topmost_widget.mouse_event(self.screen_size,
event,
button,
col,
row,
focus=True):
k = None
elif self._topmost_widget.selectable():
k = self._topmost_widget.keypress(self.screen_size, k)
if k:
if command_map[k] == 'redraw screen':
self.screen.clear()
something_handled = True
else:
something_handled |= bool(self.unhandled_input(k))
else:
something_handled = True
return something_handled
def input_filter(self, keys, raw):
"""
This function is passed each all the input events and raw
keystroke values. These values are passed to the
input_filter function passed to the constructor. That
function must return a list of keys to be passed to the
widgets to handle. If no input_filter was defined this
implementation will return all the input events.
input -- keyboard or mouse input
"""
if self._input_filter:
return self._input_filter(keys, raw)
return keys
def unhandled_input(self, input):
"""
This function is called with any input that was not handled
by the widgets, and calls the unhandled_input function passed
to the constructor. If no unhandled_input was defined then
the input will be ignored.
input -- keyboard or mouse input
The unhandled_input method should return True if it handled
the input.
"""
if self._unhandled_input:
return self._unhandled_input(input)
def entering_idle(self):
"""
This function is called whenever the event loop is about
to enter the idle state. self.draw_screen() is called here
to update the screen if anything has changed.
"""
if self.screen.started:
self.draw_screen()
def draw_screen(self):
"""
Renter the widgets and paint the screen. This function is
called automatically from run() but may be called additional
times if repainting is required without also processing input.
"""
if not self.screen_size:
self.screen_size = self.screen.get_cols_rows()
canvas = self._topmost_widget.render(self.screen_size, focus=True)
self.screen.draw_screen(self.screen_size, canvas)