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Bug 626660 - cache rendered text on a11y side, r=davidb, f=marcoz, a=betaN

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This commit is contained in:
Alexander Surkov
2011-01-31 23:53:09 +08:00
parent 4adb03f73f
commit 908cde77e7
17 changed files with 389 additions and 160 deletions
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327
accessible/src/base/NotificationController.cpp
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@@ -36,16 +36,15 @@
*
* ***** END LICENSE BLOCK ***** */
#include "nsEventShell.h"
#include "nsAccUtils.h"
#include "nsCoreUtils.h"
#include "nsDocAccessible.h"
#include "NotificationController.h"
#include "nsAccessibilityService.h"
#include "nsAccUtils.h"
#include "nsCoreUtils.h"
#include "nsDocAccessible.h"
#include "nsEventShell.h"
#include "nsTextAccessible.h"
////////////////////////////////////////////////////////////////////////////////
// NotificationCollector
@@ -574,6 +573,290 @@ NotificationController::CreateTextChangeEventFor(AccMutationEvent* aEvent)
aEvent->mIsFromUserInput ? eFromUserInput : eNoUserInput);
}
////////////////////////////////////////////////////////////////////////////////
// Notification controller: text leaf accessible text update
/**
* Used to find a difference between old and new text and fire text change
* events.
*/
class TextUpdater
{
public:
TextUpdater(nsDocAccessible* aDocument, nsTextAccessible* aTextLeaf) :
mDocument(aDocument), mTextLeaf(aTextLeaf) { }
~TextUpdater() { mDocument = nsnull; mTextLeaf = nsnull; }
/**
* Update text of the text leaf accessible, fire text change events for its
* container hypertext accessible.
*/
void Run(const nsAString& aNewText);
private:
TextUpdater();
TextUpdater(const TextUpdater&);
TextUpdater& operator = (const TextUpdater&);
/**
* Fire text change events based on difference between strings.
*/
void FindDiffNFireEvents(const nsDependentSubstring& aStr1,
const nsDependentSubstring& aStr2,
PRUint32** aMatrix,
PRUint32 aStartOffset);
/**
* Change type used to describe the diff between strings.
*/
enum ChangeType {
eNoChange,
eInsertion,
eRemoval,
eSubstitution
};
/**
* Helper to fire text change events.
*/
inline void MayFireEvent(nsAString* aInsertedText, nsAString* aRemovedText,
PRUint32 aOffset, ChangeType* aChange)
{
if (*aChange == eNoChange)
return;
if (*aChange == eRemoval || *aChange == eSubstitution) {
FireEvent(*aRemovedText, aOffset, PR_FALSE);
aRemovedText->Truncate();
}
if (*aChange == eInsertion || *aChange == eSubstitution) {
FireEvent(*aInsertedText, aOffset, PR_TRUE);
aInsertedText->Truncate();
}
*aChange = eNoChange;
}
/**
* Fire text change event.
*/
void FireEvent(const nsAString& aModText, PRUint32 aOffset, PRBool aType);
private:
nsDocAccessible* mDocument;
nsTextAccessible* mTextLeaf;
};
void
TextUpdater::Run(const nsAString& aNewText)
{
NS_ASSERTION(mTextLeaf, "No text leaf accessible?");
const nsString& oldText = mTextLeaf->Text();
PRUint32 oldLen = oldText.Length(), newLen = aNewText.Length();
PRUint32 minLen = oldLen < newLen ? oldLen : newLen;
// Skip coinciding begin substrings.
PRUint32 skipIdx = 0;
for (; skipIdx < minLen; skipIdx++) {
if (aNewText[skipIdx] != oldText[skipIdx])
break;
}
// No change, text append or removal to/from the end.
if (skipIdx == minLen) {
if (oldLen == newLen)
return;
// If text has been appended to the end, fire text inserted event.
if (oldLen < newLen) {
FireEvent(Substring(aNewText, oldLen), oldLen, PR_TRUE);
mTextLeaf->SetText(aNewText);
return;
}
// Text has been removed from the end, fire text removed event.
FireEvent(Substring(oldText, newLen), newLen, PR_FALSE);
mTextLeaf->SetText(aNewText);
return;
}
// Trim coinciding substrings from the end.
PRUint32 endIdx = minLen;
if (oldLen < newLen) {
PRUint32 delta = newLen - oldLen;
for (; endIdx > skipIdx; endIdx--) {
if (aNewText[endIdx + delta] != oldText[endIdx])
break;
}
} else {
PRUint32 delta = oldLen - newLen;
for (; endIdx > skipIdx; endIdx--) {
if (aNewText[endIdx] != oldText[endIdx + delta])
break;
}
}
PRUint32 oldEndIdx = oldLen - minLen + endIdx;
PRUint32 newEndIdx = newLen - minLen + endIdx;
// Find the difference starting from start character, we can skip initial and
// final coinciding characters since they don't affect on the Levenshtein
// distance.
const nsDependentSubstring& str1 =
Substring(oldText, skipIdx, oldEndIdx - skipIdx);
const nsDependentSubstring& str2 =
Substring(aNewText, skipIdx, newEndIdx - skipIdx);
// Compute the matrix.
PRUint32 len1 = str1.Length() + 1, len2 = str2.Length() + 1;
PRUint32** matrix = new PRUint32*[len1];
for (PRUint32 i = 0; i < len1; i++)
matrix[i] = new PRUint32[len2];
matrix[0][0] = 0;
for (PRUint32 i = 1; i < len1; i++)
matrix[i][0] = i;
for (PRUint32 j = 1; j < len2; j++)
matrix[0][j] = j;
for (PRUint32 i = 1; i < len1; i++) {
for (PRUint32 j = 1; j < len2; j++) {
if (str1[i - 1] != str2[j - 1]) {
PRUint32 left = matrix[i - 1][j];
PRUint32 up = matrix[i][j - 1];
PRUint32 upleft = matrix[i - 1][j - 1];
matrix[i][j] =
(left < up ? (upleft < left ? upleft : left) :
(upleft < up ? upleft : up)) + 1;
} else {
matrix[i][j] = matrix[i - 1][j - 1];
}
}
}
FindDiffNFireEvents(str1, str2, matrix, skipIdx);
for (PRUint32 i = 0; i < len1; i++)
delete[] matrix[i];
delete[] matrix;
mTextLeaf->SetText(aNewText);
}
void
TextUpdater::FindDiffNFireEvents(const nsDependentSubstring& aStr1,
const nsDependentSubstring& aStr2,
PRUint32** aMatrix,
PRUint32 aStartOffset)
{
// Find the difference.
ChangeType change = eNoChange;
nsAutoString insertedText;
nsAutoString removedText;
PRUint32 offset = 0;
PRInt32 i = aStr1.Length(), j = aStr2.Length();
while (i >= 0 && j >= 0) {
if (aMatrix[i][j] == 0) {
MayFireEvent(&insertedText, &removedText, offset + aStartOffset, &change);
return;
}
// move up left
if (i >= 1 && j >= 1) {
// no change
if (aStr1[i - 1] == aStr2[j - 1]) {
MayFireEvent(&insertedText, &removedText, offset + aStartOffset, &change);
i--; j--;
continue;
}
// substitution
if (aMatrix[i][j] == aMatrix[i - 1][j - 1] + 1) {
if (change != eSubstitution)
MayFireEvent(&insertedText, &removedText, offset + aStartOffset, &change);
offset = j - 1;
insertedText.Append(aStr1[i - 1]);
removedText.Append(aStr2[offset]);
change = eSubstitution;
i--; j--;
continue;
}
}
// move up, insertion
if (j >= 1 && aMatrix[i][j] == aMatrix[i][j - 1] + 1) {
if (change != eInsertion)
MayFireEvent(&insertedText, &removedText, offset + aStartOffset, &change);
offset = j - 1;
insertedText.Insert(aStr2[offset], 0);
change = eInsertion;
j--;
continue;
}
// move left, removal
if (i >= 1 && aMatrix[i][j] == aMatrix[i - 1][j] + 1) {
if (change != eRemoval) {
MayFireEvent(&insertedText, &removedText, offset + aStartOffset, &change);
offset = j;
}
removedText.Insert(aStr1[i - 1], 0);
change = eRemoval;
i--;
continue;
}
NS_NOTREACHED("Huh?");
return;
}
MayFireEvent(&insertedText, &removedText, offset + aStartOffset, &change);
}
void
TextUpdater::FireEvent(const nsAString& aModText, PRUint32 aOffset,
PRBool aIsInserted)
{
nsAccessible* parent = mTextLeaf->GetParent();
NS_ASSERTION(parent, "No parent for text leaf!");
nsHyperTextAccessible* hyperText = parent->AsHyperText();
NS_ASSERTION(hyperText, "Text leaf parnet is not hyper text!");
PRInt32 textLeafOffset = hyperText->GetChildOffset(mTextLeaf, PR_TRUE);
NS_ASSERTION(textLeafOffset != -1,
"Text leaf hasn't offset within hyper text!");
// Fire text change event.
nsRefPtr<AccEvent> textChangeEvent =
new AccTextChangeEvent(hyperText, textLeafOffset + aOffset, aModText,
aIsInserted);
mDocument->FireDelayedAccessibleEvent(textChangeEvent);
// Fire value change event.
if (hyperText->Role() == nsIAccessibleRole::ROLE_ENTRY) {
nsRefPtr<AccEvent> valueChangeEvent =
new AccEvent(nsIAccessibleEvent::EVENT_VALUE_CHANGE, hyperText,
eAutoDetect, AccEvent::eRemoveDupes);
mDocument->FireDelayedAccessibleEvent(valueChangeEvent);
}
}
PLDHashOperator
NotificationController::TextEnumerator(nsCOMPtrHashKey<nsIContent>* aEntry,
void* aUserArg)
@@ -601,12 +884,12 @@ NotificationController::TextEnumerator(nsCOMPtrHashKey<nsIContent>* aEntry,
nsIContent* containerElm = containerNode->IsElement() ?
containerNode->AsElement() : nsnull;
nsAutoString renderedText;
textFrame->GetRenderedText(&renderedText);
nsAutoString text;
textFrame->GetRenderedText(&text);
// Remove text accessible if rendered text is empty.
if (textAcc) {
if (renderedText.IsEmpty()) {
if (text.IsEmpty()) {
#ifdef DEBUG_NOTIFICATIONS
PRUint32 index = containerNode->IndexOf(textNode);
@@ -624,13 +907,36 @@ NotificationController::TextEnumerator(nsCOMPtrHashKey<nsIContent>* aEntry,
#endif
document->ContentRemoved(containerElm, textNode);
return PL_DHASH_NEXT;
}
// Update text of the accessible and fire text change events.
#ifdef DEBUG_TEXTCHANGE
PRUint32 index = containerNode->IndexOf(textNode);
nsCAutoString tag;
nsCAutoString id;
if (containerElm) {
containerElm->Tag()->ToUTF8String(tag);
nsIAtom* atomid = containerElm->GetID();
if (atomid)
atomid->ToUTF8String(id);
}
printf("\ntext may be changed: container: %s@id='%s', index in container: %d, old text '%s', new text: '%s'\n\n",
tag.get(), id.get(), index,
NS_ConvertUTF16toUTF8(textAcc->AsTextLeaf()->Text()).get(),
NS_ConvertUTF16toUTF8(text).get());
#endif
TextUpdater updater(document, textAcc->AsTextLeaf());
updater.Run(text);
return PL_DHASH_NEXT;
}
// Append an accessible if rendered text is not empty.
if (!renderedText.IsEmpty()) {
if (!text.IsEmpty()) {
#ifdef DEBUG_NOTIFICATIONS
PRUint32 index = containerNode->IndexOf(textNode);
@@ -722,3 +1028,4 @@ NotificationController::ContentInsertion::Process()
mContainer = nsnull;
mInsertedContent.Clear();
}