gcode: Keep reading input to check for M112 (emergency stop)

OctoPrint (and other software) will sometimes send additional commands
even if the previous command has not yet responded with an "ok".
Change the g-code input reading code to keep reading input so that an
M112 can be detected (and processed out-of-order).  To avoid the
extreme case where one writes an entire g-code file to the input
without any pacing, disable the input reading if more than 20 commands
are pending.

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

1 files changed, 26 insertions, 11 deletions

diff --git a/klippy/gcode.py b/klippy/gcode.py
index 5a7c50f2..38ff348a 100644
--- a/klippy/gcode.py
+++ b/klippy/gcode.py
@@ -24,6 +24,7 @@ class GCodeParser:
         if not self.is_fileinput:
             self.fd_handle = self.reactor.register_fd(self.fd, self.process_data)
         self.partial_input = ""
+        self.pending_commands = []
         self.bytes_read = 0
         self.input_log = collections.deque([], 50)
         # Command handling
@@ -172,31 +173,45 @@ class GCodeParser:
                     raise
             self.ack()
         self.need_ack = prev_need_ack
+    m112_r = re.compile('^(?:[nN][0-9]+)?\s*[mM]112(?:\s|$)')
     def process_data(self, eventtime):
+        # Read input, separate by newline, and add to pending_commands
         data = os.read(self.fd, 4096)
         self.input_log.append((eventtime, data))
         self.bytes_read += len(data)
         lines = data.split('\n')
         lines[0] = self.partial_input + lines[0]
         self.partial_input = lines.pop()
+        pending_commands = self.pending_commands
+        pending_commands.extend(lines)
+        # Check for M112 out-of-order
+        if ((len(pending_commands) > 1 or self.is_processing_data)
+            and len(pending_commands) < 20):
+            for line in lines:
+                if self.m112_r.match(line) is not None:
+                    self.cmd_M112({})
+        # Check if already processing data
         if self.is_processing_data:
-            if not self.is_fileinput and not lines:
-                return
-            self.reactor.unregister_fd(self.fd_handle)
-            self.fd_handle = None
-            if not self.is_fileinput and lines[0].strip().upper() == 'M112':
-                self.cmd_M112({})
-            while self.is_processing_data:
-                eventtime = self.reactor.pause(eventtime + 0.100)
-            self.fd_handle = self.reactor.register_fd(self.fd, self.process_data)
+            if len(pending_commands) >= 20 or not data:
+                # Stop reading input
+                self.reactor.unregister_fd(self.fd_handle)
+                self.fd_handle = None
+            return
+        # Process commands
         self.is_processing_data = True
-        self.process_commands(lines)
+        while pending_commands:
+            self.pending_commands = []
+            self.process_commands(pending_commands)
+            pending_commands = self.pending_commands
+        self.is_processing_data = False
+        # Reenable input reading if it was stopped
+        if self.fd_handle is None:
+            self.fd_handle = self.reactor.register_fd(self.fd, self.process_data)
         if not data and self.is_fileinput:
             self.motor_heater_off()
             if self.toolhead is not None:
                 self.toolhead.wait_moves()
             self.printer.request_exit()
-        self.is_processing_data = False
     def run_script(self, script):
         self.process_commands(script.split('\n'), need_ack=False)
     # Response handling