From 735fe5e20e722a2a98fea0da37a71b23c79ebb52 Mon Sep 17 00:00:00 2001
From: Charles Mita <charles.mita@diamond.ac.uk>
Date: Tue, 21 Jun 2016 10:48:50 +0100
Subject: [PATCH] Add writeable property to Method

Disallows __call__ if not set to true (true is the default value).
---
 malcolm/core/method.py                        | 11 ++++++++
 .../test_controllers/test_clientcontroller.py |  1 +
 tests/test_core/test_method.py                | 25 ++++++++++++++++++-
 3 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/malcolm/core/method.py b/malcolm/core/method.py
index c143a708d..fe0fc4396 100644
--- a/malcolm/core/method.py
+++ b/malcolm/core/method.py
@@ -16,6 +16,7 @@ def __init__(self, name, description):
         self.takes = None
         self.returns = None
         self.defaults = None
+        self.writeable = True
 
     def set_function(self, func):
         """Set the function to expose.
@@ -41,11 +42,19 @@ def set_function_returns(self, return_meta):
         """Set the return parameters for the method to validate against"""
         self.returns = return_meta
 
+    def set_writeable(self, writeable):
+        """Set writeable property to enable or disable calling method"""
+        self.writeable = writeable
+        self.on_changed([[["writeable"], writeable]])
+
     def __call__(self, *args, **kwargs):
         """Call the exposed function using regular keyword argument parameters.
         Will validate the output against provided return parameters.
         """
 
+        if not self.writeable:
+            raise ValueError("Can not call a method that is not writeable")
+
         # Assumes positional arguments represent arguments *before* any kw-args
         # in the ordered dictionary.
         for arg, arg_val in zip(self.takes.elements.keys(), args):
@@ -95,6 +104,7 @@ def to_dict(self):
         serialized["takes"] = self.takes.to_dict()
         serialized["defaults"] = self.defaults.copy()
         serialized["returns"] = self.returns.to_dict()
+        serialized["writeable"] = self.writeable
         return serialized
 
     @classmethod
@@ -110,6 +120,7 @@ def from_dict(cls, name, d):
         method.set_function_takes(takes, d["defaults"])
         returns = MapMeta.from_dict("returns", d["returns"])
         method.set_function_returns(returns)
+        method.writeable = d["writeable"]
         return method
 
     @classmethod
diff --git a/tests/test_controllers/test_clientcontroller.py b/tests/test_controllers/test_clientcontroller.py
index cd85586cb..2c3caee93 100644
--- a/tests/test_controllers/test_clientcontroller.py
+++ b/tests/test_controllers/test_clientcontroller.py
@@ -45,6 +45,7 @@ def setUp(self):
                     ),
                     required=["response"],
                 ),
+                writeable=True,
             ),
         )
 
diff --git a/tests/test_core/test_method.py b/tests/test_core/test_method.py
index 2f2ffcc31..fdb371a12 100644
--- a/tests/test_core/test_method.py
+++ b/tests/test_core/test_method.py
@@ -149,6 +149,23 @@ def test_handle_request_error(self):
         self.assertEquals(
             "Method test_method raised an error: Test error", response.message)
 
+    def test_not_writeable_stops_call(self):
+        m = Method("test_method", "test_description")
+        m.set_function(Mock())
+        m.set_writeable(False)
+        with self.assertRaises(ValueError,
+                msg="Can not call a method that is not writeable"):
+            m()
+
+    def test_set_writeable_notifies(self):
+        m = Method("test_method", "test_description")
+        m.on_changed = MagicMock(side_effect=m.on_changed)
+        m.set_writeable(False)
+        m.on_changed.assert_called_once_with([[["writeable"], False]])
+        m.on_changed.reset_mock()
+        m.set_writeable(True)
+        m.on_changed.assert_called_once_with([[["writeable"], True]])
+
     def test_to_dict_serialization(self):
         func = Mock(return_value={"out": "dummy"})
         defaults = {"in_attr": "default"}
@@ -158,15 +175,18 @@ def test_to_dict_serialization(self):
         return_meta = Mock(elements={"out": Mock()},
                            to_dict=Mock(
                                return_value=OrderedDict({"dict": "return"})))
+        writeable_mock = Mock()
         m = Method("test_method", "test_description")
         m.set_function(func)
         m.set_function_takes(args_meta, defaults)
         m.set_function_returns(return_meta)
+        m.set_writeable(writeable_mock)
         expected = OrderedDict()
         expected["description"] = "test_description"
         expected["takes"] = OrderedDict({"dict": "args"})
         expected["defaults"] = OrderedDict({"in_attr": "default"})
         expected["returns"] = OrderedDict({"dict": "return"})
+        expected["writeable"] = writeable_mock
         self.assertEquals(expected, m.to_dict())
 
     @patch("malcolm.core.method.MapMeta")
@@ -176,8 +196,10 @@ def test_from_dict_deserialize(self, mock_mapmeta):
         takes = dict(a=object(), b=object())
         returns = dict(c=object())
         defaults = dict(a=43)
+        writeable_mock = Mock()
         d = dict(description=description, takes=takes,
-                 returns=returns, defaults=defaults)
+                 returns=returns, defaults=defaults,
+                 writeable=writeable_mock)
         m = Method.from_dict(name, d)
         self.assertEqual(mock_mapmeta.from_dict.call_args_list, [
             call("takes", takes), call("returns", returns)])
@@ -185,6 +207,7 @@ def test_from_dict_deserialize(self, mock_mapmeta):
         self.assertEqual(m.takes, mock_mapmeta.from_dict.return_value)
         self.assertEqual(m.returns, mock_mapmeta.from_dict.return_value)
         self.assertEqual(m.defaults, defaults)
+        self.assertEquals(m.writeable, writeable_mock)
 
     @patch("malcolm.core.method.MapMeta")
     def test_takes_given_optional(self, map_meta_mock):