Permanent folders changes

ui/base/models/tree_node_iterator.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_BASE_MODELS_TREE_NODE_ITERATOR_H_
 #define UI_BASE_MODELS_TREE_NODE_ITERATOR_H_
 #pragma once
 
 #include <stack>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 
 namespace ui {
 
 // Iterator that iterates over the descendants of a node. The iteration does
 // not include the node itself, only the descendants. The following illustrates
 // typical usage:
 // while (iterator.has_next()) {
 //   Node* node = iterator.Next();
 //   // do something with node.
 // }
 template <class NodeType>
 class TreeNodeIterator {
  public:
-  explicit TreeNodeIterator(NodeType* node) {
+  // This contructor accepts an optional filter function |prune| which could be
+  // used to prune complete branches of the tree. The filter function will be
+  // evaluated on each of the tree node and if it evaluate to true this node and

[sky, 2011/10/14 19:50:23]

'each of the tree node' -> 'each tree node' or 'each of the tree nodes'
evaluate -> evaluates
'this node' -> 'the node'

[noyau (Ping after 24h), 2011/10/17 12:42:48]

Done.

+  // all its descendants will be skipped by the iterator.
+  explicit TreeNodeIterator(NodeType* node, bool (*prune)(NodeType*))

[sky, 2011/10/14 19:50:23]

remove explicit

[noyau (Ping after 24h), 2011/10/17 12:42:48]

Done.

+      : prune_(prune) {
+    int index;

[sky, 2011/10/14 19:50:23]

set index to 0 rather than in the for loop.

[noyau (Ping after 24h), 2011/10/17 12:42:48]

Done.

+
+    for (index = 0; index < node->child_count(); ++index)

[sky, 2011/10/14 19:50:23]

Add a comment as to what this for and if are doing.

[noyau (Ping after 24h), 2011/10/17 12:42:48]

Done.

+      if (!prune || !prune(node->GetChild(index)))
+        break;
+
+    if (index < node->child_count())
+      positions_.push(Position<NodeType>(node, index));
+  }
+
+  explicit TreeNodeIterator(NodeType* node) : prune_(NULL) {
     if (!node->empty())
       positions_.push(Position<NodeType>(node, 0));
   }
 
   // Returns true if there are more descendants.
   bool has_next() const { return !positions_.empty(); }
 
   // Returns the next descendant.
   NodeType* Next() {
     if (!has_next()) {
       NOTREACHED();
       return NULL;
     }
 
     NodeType* result = positions_.top().node->GetChild(positions_.top().index);
 
     // Make sure we don't attempt to visit result again.
     positions_.top().index++;
 
     // Iterate over result's children.
     positions_.push(Position<NodeType>(result, 0));
 
     // Advance to next position.
-    while (!positions_.empty() && positions_.top().index >=
-           positions_.top().node->child_count()) {
-      positions_.pop();
+    while (!positions_.empty()) {
+      if (positions_.top().index >= positions_.top().node->child_count())
+        positions_.pop(); // This position is all processed.
+      else if (prune_ &&
+          prune_(positions_.top().node->GetChild(positions_.top().index)))
+        positions_.top().index++;  // Prune the branch.
+      else
+        break;  // We are positioned at the next item to be processed;
     }
 
     return result;
   }
 
  private:
   template <class PositionNodeType>
   struct Position {
     Position(PositionNodeType* node, int index) : node(node), index(index) {}
     Position() : node(NULL), index(-1) {}
 
     PositionNodeType* node;
     int index;
   };
 
   std::stack<Position<NodeType> > positions_;
+  bool (*prune_)(NodeType*);
 
   DISALLOW_COPY_AND_ASSIGN(TreeNodeIterator);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_MODELS_TREE_NODE_ITERATOR_H_