# -*- coding: utf-8 -*-
#
# Copyright © 2019 Simon Forman
#
# This file is part of Thun
#
# Thun is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Thun is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Thun. If not see <http://www.gnu.org/licenses/>.
#
'''
Core
=====================
The core module defines a bunch of system-wide "constants" (some colors
and PyGame event groups), the message classes for Oberon-style message
passing, a "world" class that holds the main context for the system, and
a mainloop class that manages the, uh, main loop (the PyGame event queue.)
'''
from sys import stderr
from traceback import format_exc
import pygame
from joy.joy import run
from joy.utils.stack import stack_to_string
COMMITTER = 'Joy <auto-commit@example.com>'
BLACK = FOREGROUND = 0, 0, 0
GREY = 127, 127, 127
WHITE = BACKGROUND = 255, 255, 255
BLUE = 100, 100, 255
GREEN = 70, 200, 70
MOUSE_EVENTS = frozenset({
pygame.MOUSEMOTION,
pygame.MOUSEBUTTONDOWN,
pygame.MOUSEBUTTONUP
})
'PyGame mouse events.'
ARROW_KEYS = frozenset({
pygame.K_UP,
pygame.K_DOWN,
pygame.K_LEFT,
pygame.K_RIGHT
})
'PyGame arrow key events.'
TASK_EVENTS = tuple(range(pygame.USEREVENT, pygame.NUMEVENTS))
'Keep track of all possible task events.'
AVAILABLE_TASK_EVENTS = set(TASK_EVENTS)
'Task IDs that have not been assigned to a task.'
ALLOWED_EVENTS = [pygame.QUIT, pygame.KEYUP, pygame.KEYDOWN]
ALLOWED_EVENTS.extend(MOUSE_EVENTS)
ALLOWED_EVENTS.extend(TASK_EVENTS)
'Event "mask" for PyGame event queue, we are only interested in these event types.'
ERROR = -1
PENDING = 0
SUCCESS = 1
# 'Message status codes... dunno if this is a good idea or not...
[docs]class Message(object):
'''Message base class. Contains ``sender`` field.'''
def __init__(self, sender):
self.sender = sender
[docs]class CommandMessage(Message):
'''For commands, adds ``command`` field.'''
def __init__(self, sender, command):
Message.__init__(self, sender)
self.command = command
[docs]class ModifyMessage(Message):
'''
For when resources are modified, adds ``subject`` and ``details``
fields.
'''
def __init__(self, sender, subject, **details):
Message.__init__(self, sender)
self.subject = subject
self.details = details
[docs]class OpenMessage(Message):
'''
For when resources are modified, adds ``name``, content_id``,
``status``, and ``traceback`` fields.
'''
def __init__(self, sender, name):
Message.__init__(self, sender)
self.name = name
self.content_id = self.thing = None
self.status = PENDING
self.traceback = None
[docs]class PersistMessage(Message):
'''
For when resources are modified, adds ``content_id`` and ``details``
fields.
'''
def __init__(self, sender, content_id, **details):
Message.__init__(self, sender)
self.content_id = content_id
self.details = details
[docs]class ShutdownMessage(Message):
'''Signals that the system is shutting down.'''
# Joy Interpreter & Context
[docs]class World(object):
'''
This object contains the system context, the stack, dictionary, a
reference to the display broadcast method, and the log.
'''
def __init__(self, stack_id, stack_holder, dictionary, notify, log):
self.stack_holder = stack_holder
self.dictionary = dictionary
self.notify = notify
self.stack_id = stack_id
self.log = log.lines
self.log_id = log.content_id
[docs] def handle(self, message):
'''
Deal with updates to the stack and commands.
'''
if (isinstance(message, ModifyMessage)
and message.subject is self.stack_holder
):
self._log_lines('', '%s <-' % self.format_stack())
if not isinstance(message, CommandMessage):
return
c, s, d = message.command, self.stack_holder[0], self.dictionary
self._log_lines('', '-> %s' % (c,))
self.stack_holder[0], _, self.dictionary = run(c, s, d)
mm = ModifyMessage(self, self.stack_holder, content_id=self.stack_id)
self.notify(mm)
def _log_lines(self, *lines):
self.log.extend(lines)
self.notify(ModifyMessage(self, self.log, content_id=self.log_id))
def format_stack(self):
try:
return stack_to_string(self.stack_holder[0])
except:
print >> stderr, format_exc()
return str(self.stack_holder[0])
[docs]def push(sender, item, notify, stack_name='stack.pickle'):
'''
Helper function to push an item onto the system stack with message.
'''
om = OpenMessage(sender, stack_name)
notify(om)
if om.status == SUCCESS:
om.thing[0] = item, om.thing[0]
notify(ModifyMessage(sender, om.thing, content_id=om.content_id))
return om.status
[docs]def open_viewer_on_string(sender, content, notify):
'''
Helper function to open a text viewer on a string.
Typically used to show tracebacks.
'''
push(sender, content, notify)
notify(CommandMessage(sender, 'good_viewer_location open_viewer'))
# main loop
[docs]class TheLoop(object):
'''
The main loop manages tasks and the PyGame event queue
and framerate clock.
'''
FRAME_RATE = 24
def __init__(self, display, clock):
self.display = display
self.clock = clock
self.tasks = {}
self.running = False
[docs] def install_task(self, F, milliseconds):
'''
Install a task to run every so many milliseconds.
'''
try:
task_event_id = AVAILABLE_TASK_EVENTS.pop()
except KeyError:
raise RuntimeError('out of task ids')
self.tasks[task_event_id] = F
pygame.time.set_timer(task_event_id, milliseconds)
return task_event_id
[docs] def remove_task(self, task_event_id):
'''
Remove an installed task.
'''
assert task_event_id in self.tasks, repr(task_event_id)
pygame.time.set_timer(task_event_id, 0)
del self.tasks[task_event_id]
AVAILABLE_TASK_EVENTS.add(task_event_id)
def __del__(self):
# Best effort to cancel all running tasks.
for task_event_id in self.tasks:
pygame.time.set_timer(task_event_id, 0)
[docs] def run_task(self, task_event_id):
'''
Give a task its time to shine.
'''
task = self.tasks[task_event_id]
try:
task()
except:
traceback = format_exc()
self.remove_task(task_event_id)
print >> stderr, traceback
print >> stderr, 'TASK removed due to ERROR', task
open_viewer_on_string(self, traceback, self.display.broadcast)
[docs] def loop(self):
'''
The actual main loop machinery.
Maintain a ``running`` flag, pump the PyGame event queue and
handle the events (dispatching to the display), tick the clock.
When the loop is exited (by clicking the window close button or
pressing the ``escape`` key) it broadcasts a ``ShutdownMessage``.
'''
self.running = True
while self.running:
for event in pygame.event.get():
if event.type == pygame.QUIT:
self.running = False
elif event.type == pygame.KEYUP and event.key == pygame.K_ESCAPE:
self.running = False
elif event.type in self.tasks:
self.run_task(event.type)
else:
self.display.dispatch_event(event)
pygame.display.update()
self.clock.tick(self.FRAME_RATE)
self.display.broadcast(ShutdownMessage(self))