Bug 1883888 [wpt PR 44943] - Name unhandledrejection event correctly, a=testonly
[gecko.git] / accessible / base / TextUpdater.cpp
blob29f8ac11f31797c9ae45b752a1f532e7c31a7a49
1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* This Source Code Form is subject to the terms of the Mozilla Public
3 * License, v. 2.0. If a copy of the MPL was not distributed with this
4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 #include "TextUpdater.h"
8 #include "CacheConstants.h"
9 #include "DocAccessible-inl.h"
10 #include "TextLeafAccessible.h"
11 #include <algorithm>
13 using namespace mozilla::a11y;
15 void TextUpdater::Run(DocAccessible* aDocument, TextLeafAccessible* aTextLeaf,
16 const nsAString& aNewText) {
17 NS_ASSERTION(aTextLeaf, "No text leaf accessible?");
19 const nsString& oldText = aTextLeaf->Text();
20 uint32_t oldLen = oldText.Length(), newLen = aNewText.Length();
21 uint32_t minLen = std::min(oldLen, newLen);
23 // Skip coinciding begin substrings.
24 uint32_t skipStart = 0;
25 for (; skipStart < minLen; skipStart++) {
26 if (aNewText[skipStart] != oldText[skipStart]) break;
29 // The text was changed. Do update.
30 if (skipStart != minLen || oldLen != newLen) {
31 TextUpdater updater(aDocument, aTextLeaf);
32 updater.DoUpdate(aNewText, oldText, skipStart);
33 aDocument->QueueCacheUpdate(aTextLeaf, CacheDomain::Text);
37 void TextUpdater::DoUpdate(const nsAString& aNewText, const nsAString& aOldText,
38 uint32_t aSkipStart) {
39 LocalAccessible* parent = mTextLeaf->LocalParent();
40 if (!parent) return;
42 mHyperText = parent->AsHyperText();
43 if (!mHyperText) {
44 MOZ_ASSERT_UNREACHABLE("Text leaf parent is not hypertext!");
45 return;
48 // Get the text leaf accessible offset and invalidate cached offsets after it.
49 mTextOffset = mHyperText->GetChildOffset(mTextLeaf, true);
50 NS_ASSERTION(mTextOffset != -1, "Text leaf hasn't offset within hyper text!");
52 // Don't bother diffing if the hypertext isn't editable. Diffing non-editable
53 // text can lead to weird screen reader results with live regions, e.g.,
54 // changing "text" to "testing" might read the diff "s ing" when we'd really
55 // just like to hear "testing."
56 if (!mHyperText->IsEditable()) {
57 // Fire text change event for removal.
58 RefPtr<AccEvent> textRemoveEvent =
59 new AccTextChangeEvent(mHyperText, mTextOffset, aOldText, false);
60 mDocument->FireDelayedEvent(textRemoveEvent);
62 // Fire text change event for insertion if there's text to insert.
63 if (!aNewText.IsEmpty()) {
64 RefPtr<AccEvent> textInsertEvent =
65 new AccTextChangeEvent(mHyperText, mTextOffset, aNewText, true);
66 mDocument->FireDelayedEvent(textInsertEvent);
69 mDocument->MaybeNotifyOfValueChange(mHyperText);
71 // Update the text.
72 mTextLeaf->SetText(aNewText);
73 return;
76 uint32_t oldLen = aOldText.Length(), newLen = aNewText.Length();
77 uint32_t minLen = std::min(oldLen, newLen);
79 // Trim coinciding substrings from the end.
80 uint32_t skipEnd = 0;
81 while (minLen - skipEnd > aSkipStart &&
82 aNewText[newLen - skipEnd - 1] == aOldText[oldLen - skipEnd - 1]) {
83 skipEnd++;
86 uint32_t strLen1 = oldLen - aSkipStart - skipEnd;
87 uint32_t strLen2 = newLen - aSkipStart - skipEnd;
89 const nsAString& str1 = Substring(aOldText, aSkipStart, strLen1);
90 const nsAString& str2 = Substring(aNewText, aSkipStart, strLen2);
92 // Increase offset of the text leaf on skipped characters amount.
93 mTextOffset += aSkipStart;
95 // It could be single insertion or removal or the case of long strings. Do not
96 // calculate the difference between long strings and prefer to fire pair of
97 // insert/remove events as the old string was replaced on the new one.
98 if (strLen1 == 0 || strLen2 == 0 || strLen1 > kMaxStrLen ||
99 strLen2 > kMaxStrLen) {
100 if (strLen1 > 0) {
101 // Fire text change event for removal.
102 RefPtr<AccEvent> textRemoveEvent =
103 new AccTextChangeEvent(mHyperText, mTextOffset, str1, false);
104 mDocument->FireDelayedEvent(textRemoveEvent);
107 if (strLen2 > 0) {
108 // Fire text change event for insertion.
109 RefPtr<AccEvent> textInsertEvent =
110 new AccTextChangeEvent(mHyperText, mTextOffset, str2, true);
111 mDocument->FireDelayedEvent(textInsertEvent);
114 mDocument->MaybeNotifyOfValueChange(mHyperText);
116 // Update the text.
117 mTextLeaf->SetText(aNewText);
118 return;
121 // Otherwise find the difference between strings and fire events.
122 // Note: we can skip initial and final coinciding characters since they don't
123 // affect the Levenshtein distance.
125 // Compute the flat structured matrix need to compute the difference.
126 uint32_t len1 = strLen1 + 1, len2 = strLen2 + 1;
127 uint32_t* entries = new uint32_t[len1 * len2];
129 for (uint32_t colIdx = 0; colIdx < len1; colIdx++) entries[colIdx] = colIdx;
131 uint32_t* row = entries;
132 for (uint32_t rowIdx = 1; rowIdx < len2; rowIdx++) {
133 uint32_t* prevRow = row;
134 row += len1;
135 row[0] = rowIdx;
136 for (uint32_t colIdx = 1; colIdx < len1; colIdx++) {
137 if (str1[colIdx - 1] != str2[rowIdx - 1]) {
138 uint32_t left = row[colIdx - 1];
139 uint32_t up = prevRow[colIdx];
140 uint32_t upleft = prevRow[colIdx - 1];
141 row[colIdx] = std::min(upleft, std::min(left, up)) + 1;
142 } else {
143 row[colIdx] = prevRow[colIdx - 1];
148 // Compute events based on the difference.
149 nsTArray<RefPtr<AccEvent> > events;
150 ComputeTextChangeEvents(str1, str2, entries, events);
152 delete[] entries;
154 // Fire events.
155 for (int32_t idx = events.Length() - 1; idx >= 0; idx--) {
156 mDocument->FireDelayedEvent(events[idx]);
159 mDocument->MaybeNotifyOfValueChange(mHyperText);
161 // Update the text.
162 mTextLeaf->SetText(aNewText);
165 void TextUpdater::ComputeTextChangeEvents(
166 const nsAString& aStr1, const nsAString& aStr2, uint32_t* aEntries,
167 nsTArray<RefPtr<AccEvent> >& aEvents) {
168 int32_t colIdx = aStr1.Length(), rowIdx = aStr2.Length();
170 // Point at which strings last matched.
171 int32_t colEnd = colIdx;
172 int32_t rowEnd = rowIdx;
174 int32_t colLen = colEnd + 1;
175 uint32_t* row = aEntries + rowIdx * colLen;
176 uint32_t dist = row[colIdx]; // current Levenshtein distance
177 while (rowIdx && colIdx) { // stop when we can't move diagonally
178 if (aStr1[colIdx - 1] == aStr2[rowIdx - 1]) { // match
179 if (rowIdx < rowEnd) { // deal with any pending insertion
180 FireInsertEvent(Substring(aStr2, rowIdx, rowEnd - rowIdx), rowIdx,
181 aEvents);
183 if (colIdx < colEnd) { // deal with any pending deletion
184 FireDeleteEvent(Substring(aStr1, colIdx, colEnd - colIdx), rowIdx,
185 aEvents);
188 colEnd = --colIdx; // reset the match point
189 rowEnd = --rowIdx;
190 row -= colLen;
191 continue;
193 --dist;
194 if (dist == row[colIdx - 1 - colLen]) { // substitution
195 --colIdx;
196 --rowIdx;
197 row -= colLen;
198 continue;
200 if (dist == row[colIdx - colLen]) { // insertion
201 --rowIdx;
202 row -= colLen;
203 continue;
205 if (dist == row[colIdx - 1]) { // deletion
206 --colIdx;
207 continue;
209 MOZ_ASSERT_UNREACHABLE("huh?");
210 return;
213 if (rowEnd) FireInsertEvent(Substring(aStr2, 0, rowEnd), 0, aEvents);
214 if (colEnd) FireDeleteEvent(Substring(aStr1, 0, colEnd), 0, aEvents);