Fixes: shift+arrow key selection with MTextEdit

RevBy: Pekka Vuorela
Details: selecting just a single character with shift+arrow key didn't work
because MInputContext::update() was called due to smartMoveCursor() ->
moveCursor() -> updateMicroFocus() and at that time edit mode wasn't yet
EditModeSelect and therefore query for selected text returned nothing.
updateMicroFocus() wasn't called again after setting the mode either and just
adding that would have resulted to unnecessary update() calls, so a mechanism
to suppress actual updateMicroFocus() calls was introduced and that was used
to ensure just one updateMicroFocus() call after moving the cursor and
setting the mode.

1 files changed, 47 insertions, 14 deletions

diff --git a/src/corelib/widgets/mtextedit.cpp b/src/corelib/widgets/mtextedit.cpp
index 1d8e688d..6cfc24bc 100755
--- a/src/corelib/widgets/mtextedit.cpp
+++ b/src/corelib/widgets/mtextedit.cpp
@@ -302,7 +302,9 @@ MTextEditPrivate::MTextEditPrivate()
       completer(0),
       registeredToolbarId(-1),
       editActive(false),
-      omitInputMethodEvents(false)
+      omitInputMethodEvents(false),
+      updateMicroFocusDisabled(0),
+      pendingMicroFocusUpdate(false)
 {
 }
 
@@ -374,7 +376,7 @@ bool MTextEditPrivate::moveCursor(QTextCursor::MoveOperation moveOp,
     result = cursor()->movePosition(moveOp, moveMode, n);
     if (result) {
         q->model()->updateCursor();
-        q->updateMicroFocus();
+        updateMicroFocus();
         emit q->cursorPositionChanged();
     }
 
@@ -788,7 +790,7 @@ void MTextEditPrivate::commitPreedit()
     }
 
     setMode(MTextEditModel::EditModeBasic);
-    q->updateMicroFocus();
+    updateMicroFocus();
 
     if (q->hasFocus()) {
         // make sure the committed preedit doesn't get left on the input context
@@ -1212,7 +1214,7 @@ void MTextEditPrivate::_q_confirmCompletion(const QString &completion)
     QObject::disconnect(q, SIGNAL(textChanged()), completer, SLOT(complete()));
     emit q->textChanged();
     QObject::connect(q, SIGNAL(textChanged()), completer, SLOT(complete()));
-    q->updateMicroFocus();
+    updateMicroFocus();
 }
 
 bool MTextEditPrivate::copy()
@@ -1240,6 +1242,34 @@ QString MTextEditPrivate::replaceLineBreaks(QString text, QChar replacement)
     return text;
 }
 
+void MTextEditPrivate::disableUpdateMicroFocus()
+{
+    ++updateMicroFocusDisabled;
+}
+
+void MTextEditPrivate::enableUpdateMicroFocus(bool flush)
+{
+    Q_Q(MTextEdit);
+    Q_ASSERT(updateMicroFocusDisabled);
+    if ((--updateMicroFocusDisabled == 0) && pendingMicroFocusUpdate && flush) {
+        q->updateMicroFocus();
+    }
+    pendingMicroFocusUpdate = false;
+}
+
+void MTextEditPrivate::updateMicroFocus()
+{
+    Q_Q(MTextEdit);
+
+    if (updateMicroFocusDisabled <= 0) {
+        q->updateMicroFocus();
+        pendingMicroFocusUpdate = false;
+    } else {
+        pendingMicroFocusUpdate = true;
+    }
+}
+
+
 ///////////////////////////////////////////////
 // Actual class implementation
 
@@ -1357,7 +1387,7 @@ void MTextEdit::setSelection(int start, int length, bool useBoundaries)
 
     model()->updateCursor();
 
-    updateMicroFocus();
+    d->updateMicroFocus();
 
     emit selectionChanged();
 
@@ -1439,6 +1469,7 @@ void MTextEdit::keyPressEvent(QKeyEvent *event)
             d->smartMoveCursor(moveDirection, QTextCursor::MoveAnchor, 1);
         } else if (event->modifiers() == Qt::ShiftModifier
                    &&  (textInteractionFlags() & Qt::TextSelectableByKeyboard)) {
+            d->disableUpdateMicroFocus();
             const bool moved = d->smartMoveCursor(moveDirection, QTextCursor::KeepAnchor, 1);
             if (!wasSelecting && d->cursor()->hasSelection()) { // first character was selected
                 d->setMode(MTextEditModel::EditModeSelect);
@@ -1449,7 +1480,9 @@ void MTextEdit::keyPressEvent(QKeyEvent *event)
             }
             if (moved) {
                 emit selectionChanged();
+                d->updateMicroFocus();
             }
+            d->enableUpdateMicroFocus(true);
         }
         event->accept();
         return;
@@ -1577,7 +1610,7 @@ void MTextEdit::keyPressEvent(QKeyEvent *event)
         }
 
         model()->updateCursor();
-        updateMicroFocus();
+        d->updateMicroFocus();
         emit textChanged();
         emit cursorPositionChanged();
 
@@ -1700,7 +1733,7 @@ bool MTextEdit::insert(const QString &text)
     // either something was inserted or something was deleted, or both
     if (insertionSuccess || wasSelecting) {
         emit textChanged();
-        updateMicroFocus();
+        d->updateMicroFocus();
     }
 
     return insertionSuccess;
@@ -1751,7 +1784,7 @@ bool MTextEdit::setText(const QString &text)
 
     // only avoid signaling if empty before and after
     if (!((document()->characterCount() == 0) && wasEmpty)) {
-        updateMicroFocus();
+        d->updateMicroFocus();
         emit textChanged();
     }
 
@@ -1899,7 +1932,7 @@ void MTextEdit::handleMouseRelease(int eventCursorPosition, QGraphicsSceneMouseE
     }
 
     if (cursorPosition() != cursorPositionBefore) {
-        updateMicroFocus();
+        d->updateMicroFocus();
     }
 }
 
@@ -1988,7 +2021,7 @@ void MTextEdit::paste()
     if (changed) {
         emit textChanged();
         emit cursorPositionChanged();
-        updateMicroFocus();
+        d->updateMicroFocus();
     } else {
         mDebug("MTextEdit") << __PRETTY_FUNCTION__ << "paste failed";
         emit pasteFailed();
@@ -2021,7 +2054,7 @@ void MTextEdit::cut()
         emit selectionChanged();
         emit textChanged();
         emit cursorPositionChanged();
-        updateMicroFocus();
+        d->updateMicroFocus();
     }
 }
 
@@ -2121,7 +2154,7 @@ void MTextEdit::inputMethodEvent(QInputMethodEvent *event)
     }
 
     if (changed) {
-        updateMicroFocus();
+        d->updateMicroFocus();
         emit textChanged();
         emit cursorPositionChanged();
     }
@@ -2406,7 +2439,7 @@ void MTextEdit::deselect()
         d->setMode(MTextEditModel::EditModeBasic);
         model()->updateCursor();
         d->sendCopyAvailable(false);
-        updateMicroFocus();
+        d->updateMicroFocus();
         emit selectionChanged();
     }
 }
@@ -2581,7 +2614,7 @@ void MTextEdit::setCompleter(MCompleter *completer)
         setInputMethodAutoCapitalizationEnabled(false);
 
         if (hasFocus()) {
-            updateMicroFocus();
+            d->updateMicroFocus();
             connect(d->completer, SIGNAL(confirmed(QString, QModelIndex)),
                     this, SLOT(_q_confirmCompletion(QString)));
         }