idle_timeout: Move timeout handling from toolhead.py to new extras module

Move the "motor_off_timeout" tracking to a new module in the extras/
directory.  This makes it easier to customize the idle timeout
behavior.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/extras/idle_timeout.py

@@ -0,0 +1,48 @@
+# Support for disabling the printer on an idle timeout
+#
+# Copyright (C) 2018  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+
+DEFAULT_IDLE_GCODE = """
+M84
+"""
+
+class IdleTimeout:
+    def __init__(self, config):
+        self.printer = config.get_printer()
+        self.toolhead = None
+        self.last_timeout = 0.
+        self.idle_timeout = config.getfloat('timeout', 600., above=0.)
+        self.idle_script = config.get('gcode', DEFAULT_IDLE_GCODE)
+    def printer_state(self, state):
+        if state == 'ready':
+            self.toolhead = self.printer.lookup_object('toolhead')
+            reactor = self.printer.get_reactor()
+            reactor.register_timer(self.timeout_handler, reactor.NOW)
+    def run_idle_script(self):
+        gcode = self.printer.lookup_object('gcode')
+        for line in self.idle_script.split('\n'):
+            try:
+                res = gcode.process_batch(line)
+            except:
+                break
+            if not res:
+                # Raced with incoming g-code commands
+                return
+        self.last_timeout = self.toolhead.get_last_move_time()
+    def timeout_handler(self, eventtime):
+        info = self.toolhead.get_status(eventtime)
+        print_time = info['print_time']
+        status = info['status']
+        if print_time <= self.last_timeout or status == 'Printing':
+            return eventtime + self.idle_timeout
+        estimated_print_time = info['estimated_print_time']
+        elapsed_time = estimated_print_time - print_time
+        if elapsed_time < self.idle_timeout:
+            return eventtime + self.idle_timeout - elapsed_time
+        self.run_idle_script()
+        return eventtime + 1.
+
+def load_config(config):
+    return IdleTimeout(config)