Recalculate checksum on data change

ref #240
AdaCore · Aug 26, 2020 · dc93516 · dc93516
1 parent 8bc06c6
commit dc93516
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Showing 2 changed files with 30 additions and 7 deletions.
diff --git a/rflx/pyrflx/typevalue.py b/rflx/pyrflx/typevalue.py
@@ -835,9 +835,9 @@ def check_outgoing_condition_satisfied() -> None:
         if checksum_calculation:
             self._preset_fields(field_name)
             for checksum in self._checksums.values():
-                if not self._fields[checksum.field_name].set and self._is_checksum_settable(
-                    checksum
-                ):
+                if (
+                    not self._fields[checksum.field_name].set or checksum.calculated
+                ) and self._is_checksum_settable(checksum):
                     self._set_checksum(checksum)
 
     def _preset_fields(self, fld: str) -> None:
@@ -886,7 +886,7 @@ def set_checksum_function(self, checksums: Dict[str, Callable]) -> None:
                 )
             for field_name, checksum in self._checksums.items():
                 if field_name == checksum_field_name:
-                    checksum.set_checksum_function(checksum_function)
+                    checksum.function = checksum_function
                 else:
                     raise KeyError(
                         f"cannot set checksum function: field {checksum_field_name} "
@@ -951,6 +951,7 @@ def valid_path(value_range: ValueRange) -> bool:
 
     def _set_checksum(self, checksum: "MessageValue.Checksum") -> None:
         self._fields[checksum.field_name].typeval.assign(0)
+        checksum.calculated = True
         checksum_value = self._calculate_checksum(checksum)
         self.set(checksum.field_name, checksum_value, False)
 
@@ -1128,6 +1129,7 @@ class Checksum:
         def __init__(self, field_name: str, parameters: Sequence[Expr]):
             self.field_name = field_name
             self.function: Optional[Callable] = None
+            self.calculated = False
 
             @dataclass
             class ExpressionTuple:
@@ -1139,9 +1141,6 @@ class ExpressionTuple:
                 assert isinstance(expr, (ValueRange, Attribute, Variable))
                 self.parameters.append(ExpressionTuple(expr))
 
-        def set_checksum_function(self, function: Callable) -> None:
-            self.function = function
-
     @dataclass
     class Field(Base):
         typeval: TypeValue

diff --git a/tests/test_pyrflx.py b/tests/test_pyrflx.py
@@ -1565,6 +1565,30 @@ def test_checksum_auto_icmp(icmp_checksum: MessageValue) -> None:
     icmp_checksum.set("Data", test_data)
     assert icmp_checksum.get("Checksum") == 12824
     assert icmp_checksum.bytestring == b"\x08\x00\x32\x18\x00\x05\x00\x01" + test_data
+    assert icmp_checksum.valid_message
+
+
+def test_checksum_auto_icmp_change_field(icmp_checksum: MessageValue) -> None:
+    test_data = (
+        b"\x47\xb4\x67\x5e\x00\x00\x00\x00"
+        b"\x4a\xfc\x0d\x00\x00\x00\x00\x00\x10\x11\x12\x13\x14\x15\x16\x17"
+        b"\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f\x20\x21\x22\x23\x24\x25\x26\x27"
+        b"\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f\x30\x31\x32\x33\x34\x35\x36\x37"
+    )
+    icmp_checksum.set_checksum_function({"Checksum": icmp_checksum_function})
+    icmp_checksum.set("Tag", "Echo_Request")
+    icmp_checksum.set("Code_Zero", 0)
+    icmp_checksum.set("Identifier", 5)
+    icmp_checksum.set("Sequence_Number", 1)
+    icmp_checksum.set("Data", test_data)
+    assert icmp_checksum.get("Checksum") == 12824
+    assert icmp_checksum.bytestring == b"\x08\x00\x32\x18\x00\x05\x00\x01" + test_data
+    assert icmp_checksum.valid_message
+    icmp_checksum.set("Sequence_Number", 2)
+    icmp_checksum.set("Data", test_data)
+    assert icmp_checksum.get("Checksum") == 12823
+    assert icmp_checksum.bytestring == b"\x08\x00\x32\x17\x00\x05\x00\x02" + test_data
+    assert icmp_checksum.valid_message
 
 
 def test_checksum_parse_icmp(icmp_checksum: MessageValue) -> None: