1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/accessibility/ax_tree_update_util.h"
#include "ui/accessibility/ax_tree_update.h"
namespace ui {
// Two tree updates can be merged into one if the second one
// doesn't clear a subtree, doesn't have new tree data, and
// doesn't have a new root id - in other words the second tree
// update consists of only changes to nodes.
bool AXTreeUpdatesCanBeMerged(const AXTreeUpdate& u1, const AXTreeUpdate& u2) {
if (u2.node_id_to_clear)
return false;
if (u2.has_tree_data && u2.tree_data != u1.tree_data)
return false;
if (u2.root_id != u1.root_id)
return false;
return true;
}
bool MergeAXTreeUpdates(const std::vector<AXTreeUpdate>& src,
std::vector<AXTreeUpdate>* dst) {
size_t merge_count = 0;
for (size_t i = 1; i < src.size(); i++) {
if (AXTreeUpdatesCanBeMerged(src[i - 1], src[i]))
merge_count++;
}
// Doing a single merge isn't necessarily worth it because
// copying the tree updates takes time too so the total
// savings is less. But two more more merges is probably
// worth the overhead of copying.
if (merge_count < 2)
return false;
dst->resize(src.size() - merge_count);
(*dst)[0] = src[0];
size_t dst_index = 0;
for (size_t i = 1; i < src.size(); i++) {
if (AXTreeUpdatesCanBeMerged(src[i - 1], src[i])) {
std::vector<AXNodeData>& dst_nodes = (*dst)[dst_index].nodes;
const std::vector<AXNodeData>& src_nodes = src[i].nodes;
dst_nodes.insert(dst_nodes.end(), src_nodes.begin(), src_nodes.end());
} else {
dst_index++;
(*dst)[dst_index] = src[i];
}
}
return true;
}
} // namespace ui
|
