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Side by Side Diff: ui/base/models/tree_node_iterator.h

Issue 8759017: BookmarkModel cleanup. synced_node is now mobile_node and I'm nuking (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: Merge to trunk fix sync_integration_tests and extension test Created 9 years ago
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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be 2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file. 3 // found in the LICENSE file.
4 4
5 #ifndef UI_BASE_MODELS_TREE_NODE_ITERATOR_H_ 5 #ifndef UI_BASE_MODELS_TREE_NODE_ITERATOR_H_
6 #define UI_BASE_MODELS_TREE_NODE_ITERATOR_H_ 6 #define UI_BASE_MODELS_TREE_NODE_ITERATOR_H_
7 #pragma once 7 #pragma once
8 8
9 #include <stack> 9 #include <stack>
10 10
11 #include "base/basictypes.h" 11 #include "base/basictypes.h"
12 #include "base/logging.h" 12 #include "base/logging.h"
13 13
14 namespace ui { 14 namespace ui {
15 15
16 // Iterator that iterates over the descendants of a node. The iteration does 16 // Iterator that iterates over the descendants of a node. The iteration does
17 // not include the node itself, only the descendants. The following illustrates 17 // not include the node itself, only the descendants. The following illustrates
18 // typical usage: 18 // typical usage:
19 // while (iterator.has_next()) { 19 // while (iterator.has_next()) {
20 // Node* node = iterator.Next(); 20 // Node* node = iterator.Next();
21 // // do something with node. 21 // // do something with node.
22 // } 22 // }
23 template <class NodeType> 23 template <class NodeType>
24 class TreeNodeIterator { 24 class TreeNodeIterator {
25 public: 25 public:
26 // This contructor accepts an optional filter function |prune| which could be 26 explicit TreeNodeIterator(NodeType* node) {
27 // used to prune complete branches of the tree. The filter function will be
28 // evaluated on each tree node and if it evaluates to true the node and all
29 // its descendants will be skipped by the iterator.
30 TreeNodeIterator(NodeType* node, bool (*prune)(NodeType*))
31 : prune_(prune) {
32 int index = 0;
33
34 // Move forward through the children list until the first non prunable node.
35 // This is to satisfy the iterator invariant that the current index in the
36 // Position at the top of the _positions list must point to a node the
37 // iterator will be returning.
38 for (; index < node->child_count(); ++index)
39 if (!prune || !prune(node->GetChild(index)))
40 break;
41
42 if (index < node->child_count())
43 positions_.push(Position<NodeType>(node, index));
44 }
45
46 explicit TreeNodeIterator(NodeType* node) : prune_(NULL) {
47 if (!node->empty()) 27 if (!node->empty())
48 positions_.push(Position<NodeType>(node, 0)); 28 positions_.push(Position<NodeType>(node, 0));
49 } 29 }
50 30
51 // Returns true if there are more descendants. 31 // Returns true if there are more descendants.
52 bool has_next() const { return !positions_.empty(); } 32 bool has_next() const { return !positions_.empty(); }
53 33
54 // Returns the next descendant. 34 // Returns the next descendant.
55 NodeType* Next() { 35 NodeType* Next() {
56 if (!has_next()) { 36 if (!has_next()) {
57 NOTREACHED(); 37 NOTREACHED();
58 return NULL; 38 return NULL;
59 } 39 }
60 40
61 // There must always be a valid node in the current Position index. 41 // There must always be a valid node in the current Position index.
62 NodeType* result = positions_.top().node->GetChild(positions_.top().index); 42 NodeType* result = positions_.top().node->GetChild(positions_.top().index);
63 43
64 // Make sure we don't attempt to visit result again. 44 // Make sure we don't attempt to visit result again.
65 positions_.top().index++; 45 positions_.top().index++;
66 46
67 // Iterate over result's children. 47 // Iterate over result's children.
68 positions_.push(Position<NodeType>(result, 0)); 48 positions_.push(Position<NodeType>(result, 0));
69 49
70 // Advance to next valid node by skipping over the pruned nodes and the 50 while (!positions_.empty() &&
71 // empty Positions. At the end of this loop two cases are possible: 51 positions_.top().index >= positions_.top().node->child_count()) {
72 // - the current index of the top() Position points to a valid node 52 positions_.pop(); // This Position is all processed, move to the next.
73 // - the _position list is empty, the iterator has_next() will return false.
74 while (!positions_.empty()) {
75 if (positions_.top().index >= positions_.top().node->child_count())
76 positions_.pop(); // This Position is all processed, move to the next.
77 else if (prune_ &&
78 prune_(positions_.top().node->GetChild(positions_.top().index)))
79 positions_.top().index++; // Prune the branch.
80 else
81 break; // Now positioned at the next node to be returned.
82 } 53 }
83 54
84 return result; 55 return result;
85 } 56 }
86 57
87 private: 58 private:
88 template <class PositionNodeType> 59 template <class PositionNodeType>
89 struct Position { 60 struct Position {
90 Position(PositionNodeType* node, int index) : node(node), index(index) {} 61 Position(PositionNodeType* node, int index) : node(node), index(index) {}
91 Position() : node(NULL), index(-1) {} 62 Position() : node(NULL), index(-1) {}
92 63
93 PositionNodeType* node; 64 PositionNodeType* node;
94 int index; 65 int index;
95 }; 66 };
96 67
97 std::stack<Position<NodeType> > positions_; 68 std::stack<Position<NodeType> > positions_;
98 bool (*prune_)(NodeType*);
99 69
100 DISALLOW_COPY_AND_ASSIGN(TreeNodeIterator); 70 DISALLOW_COPY_AND_ASSIGN(TreeNodeIterator);
101 }; 71 };
102 72
103 } // namespace ui 73 } // namespace ui
104 74
105 #endif // UI_BASE_MODELS_TREE_NODE_ITERATOR_H_ 75 #endif // UI_BASE_MODELS_TREE_NODE_ITERATOR_H_
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