/**
* 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++;
}
/**
* Same as {@link #restoreSelection()}, but if the selection is actually required to be explicitly
* set, transform its saved location with the given modifier.
*/
public void restoreSelection(DocOp modifier) {
savedSelectionDepth--;
if (editingConcerns != null && savedSelectionDepth == 0) {
try {
if (savedSelection != null) {
// selectionChangedInappropriately() only deals with selection boundaries. If we had
// a ranged selection, and we're in a browser where changing it internally matters,
// then just always restore the selection. This is safe to do w.r.t. IMEs because it's
// unlikely to have a ranged selection during an uncommitted IME state.
needToRestoreSelection |=
QuirksConstants.RANGED_SELECTION_AFFECTED_BY_INTERNAL_CHANGED
&& !savedSelection.isCollapsed();
if (needToRestoreSelection || selectionChangedInappropriately()) {
if (modifier != null) {
savedSelection = RangeHelper.applyModifier(savedSelection, modifier);
}
EditorStaticDeps.logger.trace().log("Restoring selection");
if (document.size() >= 4) {
editingConcerns.getSelectionHelper().setSelectionRange(savedSelection);
}
} else {
EditorStaticDeps.logger.trace().log("Not restoring selection");
}
}
} finally {
savedSelection = null;
savedSelectionAnchor = null;
savedSelectionAnchorTextNodelet = null;
savedSelectionAnchorOffset = 0;
savedSelectionFocus = null;
savedSelectionFocusTextNodelet = null;
savedSelectionFocusOffset = 0;
}
}
}
