protocol: implement the message to wait for the end of pen data

This pushes the CRC fetching into the messages, making the caller code more
generic.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

tuhi/protocol.py

@@ -119,6 +119,7 @@ class Interactions(enum.Enum):
     AVAILABLE_FILES_COUNT = enum.auto()
     DOWNLOAD_OLDEST_FILE = enum.auto()
     DELETE_OLDEST_FILE = enum.auto()
+    WAIT_FOR_END_READ = enum.auto()
     REGISTER_PRESS_BUTTON = enum.auto()
     REGISTER_WAIT_FOR_BUTTON = enum.auto()
     REGISTER_COMPLETE = enum.auto()
@@ -1134,6 +1135,62 @@ class MsgDownloadOldestFile(Msg):
             raise UnexpectedDataError(reply)
 
 
+class MsgWaitForEndRead(Msg):
+    '''
+    .. attribute:: crc
+
+        The checksum provided for the (out of band) pen data.
+    '''
+    interaction = Interactions.WAIT_FOR_END_READ
+    requires_request = False
+    opcode = 0x00  # unused
+    protocol = ProtocolVersion.ANY
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(timeout=5, *args, **kwargs)
+
+    def _handle_reply(self, reply):
+        if reply.opcode == 0xc8:
+            if reply[0] != 0xed:
+                raise UnexpectedDataError(reply, 'Expected c8 ed')
+            pass  # nothing to do here
+        elif reply.opcode == 0xc9:
+            self.crc = int(binascii.hexlify(bytes(reply)), 16)
+        else:
+            raise UnexpectedReply(reply)
+
+    def execute(self):
+        # This is a double-reply , once c8, then c9
+        super().execute()
+        super().execute()
+        return self
+
+
+class MsgWaitForEndReadSlate(Msg):
+    '''
+    .. attribute:: crc
+
+        The checksum provided for the (out of band) pen data.
+    '''
+    interaction = Interactions.WAIT_FOR_END_READ
+    requires_request = False
+    opcode = 0x00  # unused
+    protocol = ProtocolVersion.SLATE
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(timeout=5, *args, **kwargs)
+
+    def _handle_reply(self, reply):
+        if reply.opcode == 0xc8:
+            if reply[0] != 0xed:
+                raise UnexpectedDataError(reply, 'Expected c8 ed')
+            crc = reply[1:]
+            crc.reverse()
+            self.crc = int(binascii.hexlify(bytes(crc)), 16)
+        else:
+            raise UnexpectedReply(reply)
+
+
 class MsgDeleteOldestFile(Msg):
     interaction = Interactions.DELETE_OLDEST_FILE
     opcode = 0xca

tuhi/wacom.py

@@ -633,17 +633,21 @@ class WacomProtocolBase(WacomProtocolLowLevelComm):
 
         return data
 
-    def wait_for_end_read(self):
-        data = self.wait_nordic_unless_pen_data(0xc8, 5)
-        if data[0] != 0xed:
-            raise WacomException(f'unexpected answer: {data[0]:02x}')
-        data = self.wait_nordic_data(0xc9, 5)
-        crc = data
-        crc = int(binascii.hexlify(bytes(crc)), 16)
+    def wait_for_end_read(self, timeout=5):
+        msg = None
+        while True:
+            try:
+                msg = self.p.execute(Interactions.WAIT_FOR_END_READ)
+                break
+            except WacomTimeoutException as e:
+                # if we're still reading pen data, try again
+                if time.time() - self._last_pen_data_time > timeout:
+                    raise e
+
         pen_data = self.pen_data_buffer
         self.pen_data_buffer = []
-        if crc != binascii.crc32(bytes(pen_data)):
-            logger.error("CRCs don't match")
+        if msg.crc != binascii.crc32(bytes(pen_data)):
+            raise UnexpectedDataError(pen_data, message='CRCs do not match')
         return pen_data
 
     def retrieve_data(self):
@@ -857,19 +861,6 @@ class WacomProtocolSlate(WacomProtocolSpark):
             else:
                 raise e
 
-    def wait_for_end_read(self):
-        data = self.wait_nordic_unless_pen_data(0xc8, timeout=5)
-        if data[0] != 0xed:
-            raise WacomException(f'unexpected answer: {data[0]:02x}')
-        crc = data[1:]
-        crc.reverse()
-        crc = int(binascii.hexlify(bytes(crc)), 16)
-        pen_data = self.pen_data_buffer
-        self.pen_data_buffer = []
-        if crc != binascii.crc32(bytes(pen_data)):
-            raise UnexpectedDataError(pen_data, message='CRCs do not match')
-        return pen_data
-
 
 class WacomProtocolIntuosPro(WacomProtocolSlate):
     '''