[ui] first basic debugging UI + elementary commands

* nodes as a ListView (right click to delete a node)
* editable attributes 
* undo/redo for adding/removing nodes and attribute edition

meshroom/ui/commands.py

@@ -0,0 +1,97 @@
+from PySide2 import QtWidgets
+from meshroom.processGraph.graph import Node
+
+
+class UndoCommand(QtWidgets.QUndoCommand):
+    def __init__(self, parent=None):
+        super(UndoCommand, self).__init__(parent)
+        self._enabled = True
+
+    def setEnabled(self, enabled):
+        self._enabled = enabled
+
+    def redo(self):
+        if not self._enabled:
+            return
+        self.redoImpl()
+
+    def undo(self):
+        if not self._enabled:
+            return
+        self.undoImpl()
+
+    def redoImpl(self) -> bool:
+        pass
+
+    def undoImpl(self) -> bool:
+        pass
+
+
+class UndoStack(QtWidgets.QUndoStack):
+    def __init__(self, parent=None):
+        super(UndoStack, self).__init__(parent)
+
+    def tryAndPush(self, command: UndoCommand):
+        if command.redoImpl():
+            command.setEnabled(False)
+            self.push(command)  # takes ownership
+            command.setEnabled(True)
+            return True
+        else:
+            return False
+
+
+class GraphCommand(UndoCommand):
+    def __init__(self, graph, parent=None):
+        super(GraphCommand, self).__init__(parent)
+        self.graph = graph
+
+
+class AddNodeCommand(GraphCommand):
+    def __init__(self, graph, nodeType, parent=None):
+        super(AddNodeCommand, self).__init__(graph, parent)
+        self.nodeType = nodeType
+        self.node = None
+
+    def redoImpl(self):
+        self.node = self.graph.addNewNode(self.nodeType)
+        self.setText("Add Node {}".format(self.node.getName()))
+        return True
+
+    def undoImpl(self):
+        self.graph.removeNode(self.node.getName())
+        self.node = None
+
+
+class RemoveNodeCommand(GraphCommand):
+    def __init__(self, graph, node, parent=None):
+        super(RemoveNodeCommand, self).__init__(graph, parent)
+        self.nodeDesc = node.toDict()
+        self.nodeName = node.getName()
+        self.setText("Remove Node {}".format(self.nodeName))
+
+    def redoImpl(self):
+        self.graph.removeNode(self.nodeName)
+        return True
+
+    def undoImpl(self):
+        node = self.graph.addNode(Node(nodeDesc=self.nodeDesc["nodeType"],
+                                       parent=self.graph, **self.nodeDesc["attributes"]
+                                       ), self.nodeName)
+        assert (node.getName() == self.nodeName)
+
+
+class SetAttributeCommand(GraphCommand):
+    def __init__(self, graph, attribute, value, parent=None):
+        super(SetAttributeCommand, self).__init__(graph, parent)
+        self.nodeName = attribute.node.getName()
+        self.attrName = attribute.getName()
+        self.value = value
+        self.oldValue = attribute.getValue()
+
+    def redoImpl(self):
+        self.graph.node(self.nodeName).attribute(self.attrName).setValue(self.value)
+        return True
+
+    def undoImpl(self):
+        self.graph.node(self.nodeName).attribute(self.attrName).setValue(self.oldValue)