[core] Add new type of ChoiceParam that changes dynamically according to other values

Add new type of ChoiceParam that changes dynamically according to other
values.

When value of an attribute is changed onAttributeChanged is called,
allowing to have unique reaction within node files.

Also add of callDesc function to be able to have other functions such as
onNodeCreated at creation of node.

meshroom/core/attribute.py

@@ -7,7 +7,7 @@ import weakref
 import types
 import logging
 
-from collections.abc import Sequence
+from collections.abc import Iterable, Sequence
 from string import Template
 from meshroom.common import BaseObject, Property, Variant, Signal, ListModel, DictModel, Slot
 from meshroom.core import desc, hashValue
@@ -29,6 +29,8 @@ def attributeFactory(description, value, isOutput, node, root=None, parent=None)
         cls = GroupAttribute
     elif isinstance(description, desc.ListAttribute):
         cls = ListAttribute
+    elif isinstance(description, desc.ChoiceParam):
+        cls = ChoiceParam
     else:
         cls = Attribute
     attr = cls(node, description, isOutput, root, parent)
@@ -170,6 +172,9 @@ class Attribute(BaseObject):
             return
         self._validValue = value
 
+    def validateValue(self, value):
+        return self.desc.validateValue(value)
+
     def _get_value(self):
         if self.isLink:
             return self.getLinkParam().value
@@ -185,8 +190,10 @@ class Attribute(BaseObject):
         else:
             # if we set a new value, we use the attribute descriptor validator to check the validity of the value
             # and apply some conversion if needed
-            convertedValue = self.desc.validateValue(value)
+            convertedValue = self.validateValue(value)
             self._value = convertedValue
+
+        self.node.onAttributeChanged(self)
         # Request graph update when input parameter value is set
         # and parent node belongs to a graph
         # Output attributes value are set internally during the update process,
@@ -392,6 +399,43 @@ def raiseIfLink(func):
     return wrapper
 
 
+class ChoiceParam(Attribute):
+
+    def __init__(self, node, attributeDesc, isOutput, root=None, parent=None):
+        super(ChoiceParam, self).__init__(node, attributeDesc, isOutput, root, parent)
+        self._values = None
+
+    def getValues(self):
+        return self._values if self._values is not None else self.desc._values
+
+    def conformValue(self, val):
+        """ Conform 'val' to the correct type and check for its validity """
+        return self.desc._valueType(val)
+
+    def validateValue(self, value):
+        if self.desc.exclusive:
+            return self.conformValue(value)
+
+        if isinstance(value, str):
+            value = value.split(',')
+
+        if not isinstance(value, Iterable):
+            raise ValueError('Non exclusive ChoiceParam value should be iterable (param:{}, value:{}, type:{})'.format(self.name, value, type(value)))
+        return [self.conformValue(v) for v in value]
+
+    def setValues(self, values):
+        if values == self._values:
+            return
+        self._values = values
+        self.valuesChanged.emit()
+
+    def __len__(self):
+        return len(self.getValues())
+
+    valuesChanged = Signal()
+    values = Property(Variant, getValues, setValues, notify=valuesChanged)
+
+
 class ListAttribute(Attribute):
 
     def __init__(self, node, attributeDesc, isOutput, root=None, parent=None):
@@ -567,7 +611,7 @@ class GroupAttribute(Attribute):
                 raise AttributeError(key)
 
     def _set_value(self, exportedValue):
-        value = self.desc.validateValue(exportedValue)
+        value = self.validateValue(exportedValue)
         if isinstance(value, dict):
             # set individual child attribute values
             for key, v in value.items():
@@ -581,7 +625,7 @@ class GroupAttribute(Attribute):
             raise AttributeError("Failed to set on GroupAttribute: {}".format(str(value)))
 
     def upgradeValue(self, exportedValue):
-        value = self.desc.validateValue(exportedValue)
+        value = self.validateValue(exportedValue)
         if isinstance(value, dict):
             # set individual child attribute values
             for key, v in value.items():