Snippets: Track begin of first selection

Since in the snippets overlay the selections are created with
ExpandBegin the interest is mostly in detecting when the first one
moved to the left (for example, when an undo is performed right
after inserting the snippet). However, this tracking doesn't need
to necessarily be associated with that flag.

src/plugins/texteditor/basetexteditor.cpp

@@ -670,10 +670,7 @@ void BaseTextEditor::editorContentsChange(int position, int charsRemoved, int ch
     if (d->m_snippetOverlay->isVisible()) {
         QTextCursor cursor = textCursor();
         cursor.setPosition(position);
-        if (!d->m_snippetOverlay->hasCursorInSelection(cursor)) {
-            d->m_snippetOverlay->hide();
-            d->m_snippetOverlay->clear();
-        }
+        d->snippetCheckCursor(cursor);
     }
 
     if (doc->isRedoAvailable())
@@ -2455,7 +2452,8 @@ bool BaseTextEditorPrivate::snippetCheckCursor(const QTextCursor &cursor)
     QTextCursor end = cursor;
     end.setPosition(cursor.selectionEnd());
     if (!m_snippetOverlay->hasCursorInSelection(start)
-        || !m_snippetOverlay->hasCursorInSelection(end)) {
+        || !m_snippetOverlay->hasCursorInSelection(end)
+        || m_snippetOverlay->hasFirstSelectionBeginMoved()) {
         m_snippetOverlay->setVisible(false);
         m_snippetOverlay->clear();
         return false;

src/plugins/texteditor/texteditoroverlay.cpp

@@ -43,6 +43,7 @@ TextEditorOverlay::TextEditorOverlay(BaseTextEditor *editor) :
     m_borderWidth(1),
     m_dropShadowWidth(2),
     m_alpha(true),
+    m_firstSelectionOriginalBegin(-1),
     m_editor(editor),
     m_viewport(editor->viewport())
 {
@@ -69,6 +70,7 @@ void TextEditorOverlay::clear()
     if (m_selections.isEmpty())
         return;
     m_selections.clear();
+    m_firstSelectionOriginalBegin = -1;
     update();
 }
 
@@ -94,13 +96,16 @@ void TextEditorOverlay::addOverlaySelection(int begin, int end,
         }
     }
 
-
     if (overlaySelectionFlags & LockSize)
         selection.m_fixedLength = (end - begin);
 
-
     selection.m_dropShadow = (overlaySelectionFlags & DropShadow);
 
+    if (m_selections.isEmpty())
+        m_firstSelectionOriginalBegin = begin;
+    else if (begin < m_firstSelectionOriginalBegin)
+        qWarning() << "overlay selections not in order";
+
     m_selections.append(selection);
     update();
 }
@@ -525,3 +530,10 @@ void TextEditorOverlay::updateEquivalentSelections(const QTextCursor &cursor)
         }
     }
 }
+
+bool TextEditorOverlay::hasFirstSelectionBeginMoved() const
+{
+    if (m_firstSelectionOriginalBegin == -1 || m_selections.isEmpty())
+        return false;
+    return m_selections.at(0).m_cursor_begin.position() != m_firstSelectionOriginalBegin;
+}

src/plugins/texteditor/texteditoroverlay.h

@@ -101,6 +101,8 @@ public:
     void mapEquivalentSelections();
     void updateEquivalentSelections(const QTextCursor &cursor);
 
+    bool hasFirstSelectionBeginMoved() const;
+
 private:
     QPainterPath createSelectionPath(const QTextCursor &begin, const QTextCursor &end, const QRect& clip);
     void paintSelection(QPainter *painter, const OverlaySelection &selection);
@@ -113,6 +115,7 @@ private:
     int m_borderWidth;
     int m_dropShadowWidth;
     bool m_alpha;
+    int m_firstSelectionOriginalBegin;
     BaseTextEditor *m_editor;
     QWidget *m_viewport;
     QList<OverlaySelection> m_selections;