Extract StcAutoProtocol class, fix autodetection

With the introduction of real abstract classes, it is not possible
anymore to instantiate StcBaseProtocol. Instead, extract some of the
code for autodetection into the new class StcAutoProtocol and use
that for autodetection.

stcgal/frontend.py

@@ -32,7 +32,10 @@ class StcGal:
 
     def __init__(self, opts):
         self.opts = opts
+        self.initialize_protocol(opts)
 
+    def initialize_protocol(self, opts):
+        """Initialize protocol backend"""
         if opts.protocol == "stc89":
             self.protocol = Stc89Protocol(opts.port, opts.handshake, opts.baud)
         elif opts.protocol == "stc12a":
@@ -50,8 +53,7 @@ class StcGal:
         elif opts.protocol == "usb15":
             self.protocol = StcUsb15Protocol()
         else:
-            self.protocol = StcBaseProtocol(opts.port, opts.handshake, opts.baud)
+            self.protocol = StcAutoProtocol(opts.port, opts.handshake, opts.baud)
-
         self.protocol.debug = opts.debug
 
     def emit_options(self, options):
@@ -133,14 +135,14 @@ class StcGal:
 
         try:
             self.protocol.connect(autoreset=self.opts.autoreset, resetcmd=self.opts.resetcmd)
-            if self.opts.protocol == "auto":
+            if isinstance(self.protocol, StcAutoProtocol):
                 if not self.protocol.protocol_name:
                     raise StcProtocolException("cannot detect protocol")
                 base_protocol = self.protocol
                 self.opts.protocol = self.protocol.protocol_name
                 print("Protocol detected: %s" % self.opts.protocol)
                 # recreate self.protocol with proper protocol class
-                self.__init__(self.opts)
+                self.initialize_protocol(self.opts)
             else:
                 base_protocol = None
 

stcgal/protocols.py

@@ -202,20 +202,6 @@ class StcBaseProtocol(ABC):
             mcu_name += "E" if self.status_packet[17] < 0x70 else "W"
             self.model = self.model._replace(name = mcu_name)
 
-        protocol_database = [("stc89", r"STC(89|90)(C|LE)\d"),
-                             ("stc12a", r"STC12(C|LE)\d052"),
-                             ("stc12b", r"STC12(C|LE)(52|56)"),
-                             ("stc12", r"(STC|IAP)(10|11|12)\D"),
-                             ("stc15a", r"(STC|IAP)15[FL][01]0\d(E|EA|)$"),
-                             ("stc15", r"(STC|IAP|IRC)15\D")]
-
-        for protocol_name, pattern in protocol_database:
-            if re.match(pattern, self.model.name):
-                self.protocol_name = protocol_name
-                break
-        else:
-            self.protocol_name = None
-
     def get_status_packet(self):
         """Read and decode status packet"""
 
@@ -318,7 +304,11 @@ class StcBaseProtocol(ABC):
         """Initialize options from status packet"""
         pass
 
-    def initialize(self, base_protocol = None):
+    def initialize(self, base_protocol=None):
+        """
+        Initialize from another instance. This is an alternative for calling
+        connect() and is used by protocol autodetection.
+        """
         if base_protocol:
             self.ser = base_protocol.ser
             self.ser.parity = self.PARITY
@@ -346,6 +336,39 @@ class StcBaseProtocol(ABC):
         print("Disconnected!")
 
 
+class StcAutoProtocol(StcBaseProtocol):
+    """
+    Protocol handler for autodetection of protocols. Does not implement full
+    functionality for any device class.
+    """
+
+    def initialize_model(self):
+        super().initialize_model()
+
+        protocol_database = [("stc89", r"STC(89|90)(C|LE)\d"),
+                             ("stc12a", r"STC12(C|LE)\d052"),
+                             ("stc12b", r"STC12(C|LE)(52|56)"),
+                             ("stc12", r"(STC|IAP)(10|11|12)\D"),
+                             ("stc15a", r"(STC|IAP)15[FL][01]0\d(E|EA|)$"),
+                             ("stc15", r"(STC|IAP|IRC)15\D")]
+
+        for protocol_name, pattern in protocol_database:
+            if re.match(pattern, self.model.name):
+                self.protocol_name = protocol_name
+                break
+        else:
+            self.protocol_name = None
+
+    def initialize_options(self, status_packet):
+        raise NotImplementedError
+
+    def initialize_status(self, status_packet):
+        raise NotImplementedError
+
+    def write_packet(self, packet_data):
+        raise NotImplementedError
+
+
 class Stc89Protocol(StcBaseProtocol):
     """Protocol handler for STC 89/90 series"""
 

test/test_program.py

@@ -133,4 +133,3 @@ class ProgramTests(unittest.TestCase):
             read_mock.side_effect = convert_to_bytes(test_data["responses"])
             gal = stcgal.frontend.StcGal(opts)
             self.assertEqual(gal.run(), 0)
-