/**
* Enter a block where the selection will be preserved against the adverse effects of dom
* mutation.
*
* <p>Must be balanced with a call to either {@link #restoreSelection()} or {@link
* #restoreSelection(DocOp)}
*
* <p>Code that mutates the HTML dom must be guarded by calls to save and restore.
*/
public void saveSelection() {
if (editingConcerns != null && savedSelectionDepth == 0) {
needToRestoreSelection = false;
SelectionHelper helper = editingConcerns.getSelectionHelper();
// Sometimes the document is not in an editing context, in which
// case there is no selection helper.
if (helper != null) {
FocusedPointRange<Node> htmlSelection = NativeSelectionUtil.get();
if (htmlSelection != null) {
savedSelectionAnchor = htmlSelection.getAnchor();
if (savedSelectionAnchor.isInTextNode()) {
savedSelectionAnchorTextNodelet = savedSelectionAnchor.getContainer().cast();
savedSelectionAnchorOffset = savedSelectionAnchor.getTextOffset();
}
savedSelectionFocus = htmlSelection.getFocus();
if (savedSelectionFocus.isInTextNode()) {
savedSelectionFocusTextNodelet = savedSelectionFocus.getContainer().cast();
savedSelectionFocusOffset = savedSelectionFocus.getTextOffset();
}
savedSelection = helper.getSelectionRange();
}
}
}
savedSelectionDepth++;
}
/**
* Checks if the selection has been removed, or is somewhere where we are not expecting it to be.
*/
private boolean selectionChangedInappropriately() {
// The selection got lost. We need to restore it
if (!NativeSelectionUtil.selectionExists()) {
return true;
}
NativeSelectionUtil.cacheClear();
FocusedPointRange<Node> htmlSelection = NativeSelectionUtil.get();
Point<Node> newAnchor = htmlSelection.getAnchor();
if (savedSelectionAnchor.isInTextNode()) {
if (savedSelectionAnchorTextNodelet != newAnchor.getContainer()
|| savedSelectionAnchorOffset != newAnchor.getTextOffset()) {
return true;
}
} else {
if (savedSelectionAnchor.getContainer() != newAnchor.getContainer()) {
return true;
}
}
Point<Node> newFocus = htmlSelection.getFocus();
if (savedSelectionFocus.isInTextNode()) {
if (savedSelectionFocusTextNodelet != newFocus.getContainer()
|| savedSelectionFocusOffset != newFocus.getTextOffset()) {
return true;
}
} else {
if (savedSelectionFocus.getContainer() != newFocus.getContainer()) {
return true;
}
}
return false;
}