[ZPT] CVS: Zope/lib/python/ZTUtils - Tree.py:1.13

[Martijn Pieters]

Update of /cvs-repository/Zope/lib/python/ZTUtils
In directory cvs.zope.org:/tmp/cvs-serv4057/lib/python/ZTUtils

Modified Files:
	Tree.py 
Log Message:
New method setStateFunction for TreeMaker.

- Refactor tree method to allow callback function (set with
  setStateFunction) to influence node state.

- hasChildren now stores the result of getChildren in a local cache, which
  getChildren uses and clears on a subsequent call. This was needed to avoid
  generating the children list for open nodes twice.

- hasChildren now flattens its return value to a boolean; tree relies on
  this.


=== Zope/lib/python/ZTUtils/Tree.py 1.12 => 1.13 ===
--- Zope/lib/python/ZTUtils/Tree.py:1.12	Fri Oct  4 22:10:01 2002
+++ Zope/lib/python/ZTUtils/Tree.py	Sat Oct  5 17:24:03 2002
@@ -64,8 +64,11 @@
     _assume_children = 0
     _values_filter = None
     _values_function = None
+    _state_function = None
     _expand_root = 1
 
+    _cached_children = None
+
     def setChildAccess(self, attrname=_marker, filter=_marker,
                        function=_marker):
         '''Set the criteria for fetching child nodes.
@@ -120,6 +123,23 @@
         """
         self._assume_children = assume and True or False
 
+    def setStateFunction(self, function):
+        """Set the expansion state function.
+
+        This function will be called to determine if a node should be open or
+        collapsed, or should be treated as a leaf node. The function is passed
+        the current object, and the intended state for that object. It should
+        return the actual state the object should be in. State is encoded as an
+        integer, meaning:
+
+            -1: Node closed. Children will not be processed.
+             0: Leaf node, cannot be opened or closed, no children are
+                processed.
+             1: Node opened. Children will be processed as part of the tree.
+        
+        """
+        self._state_function = function
+
     def tree(self, root, expanded=None, subtree=0):
         '''Create a tree from root, with specified nodes expanded.
 
@@ -134,14 +154,17 @@
             # Assume a mapping
             expanded = expanded.has_key(node.id)
             child_exp = child_exp.get(node.id)
-        if expanded or (not subtree and self._expand_root):
-            children = self.getChildren(root)
-            if children:
-                node.state = 1 # expanded
-                for child in children:
-                    node._add_child(self.tree(child, child_exp, 1))
-        elif self.hasChildren(root):
-            node.state = -1 # collapsed
+
+        expanded = expanded or (not subtree and self._expand_root)
+        # Set state to 0 (leaf), 1 (opened), or -1 (closed)
+        state = self.hasChildren(root) and (expanded or -1)
+        if self._state_function is not None:
+            state = self._state_function(node.object, state)
+        node.state = state
+        if state > 0:
+            for child in self.getChildren(root):
+                node._add_child(self.tree(child, child_exp, 1))
+
         if not subtree:
             node.depth = 0
         return node
@@ -164,9 +187,18 @@
     def hasChildren(self, object):
         if self._assume_children:
             return 1
-        return self.getChildren(object)
+        # Cache generated children for a subsequent call to getChildren
+        self._cached_children = (object, self.getChildren(object))
+        return not not self._cached_children[1]
 
     def getChildren(self, object):
+        # Check and clear cache first
+        if self._cached_children is not None:
+            ob, children = self._cached_children
+            self._cached_children = None
+            if ob is object:
+                return children
+    
         if self._values_function is not None:
             return self._values_function(object)