Use function to convert indices for text protocol

Use a proper function instead of left/midRef(index).toUtf8().size().

Makes it more clear what is happening and makes it easier when wayland
text protocol switches from byte-based to unicode character-based indices.

Also rename parameters of existing indexFromWayland() function to be the
same as in the new function.

Change-Id: Ie90abdcb264b74a024e96e041d5daf651920e9e4
Reviewed-by: Giulio Camuffo <giulio.camuffo@kdab.com>

4 files changed, 23 insertions, 17 deletions

diff --git a/src/client/qwaylandinputcontext.cpp b/src/client/qwaylandinputcontext.cpp
index f211780fd..af8e6f818 100644
--- a/src/client/qwaylandinputcontext.cpp
+++ b/src/client/qwaylandinputcontext.cpp
@@ -157,7 +157,7 @@ void QWaylandTextInput::updateState(Qt::InputMethodQueries queries, uint32_t fla
             anchor -= offset;
         }
 
-        set_surrounding_text(text, text.leftRef(cursor).toUtf8().size(), text.leftRef(anchor).toUtf8().size());
+        set_surrounding_text(text, QWaylandInputMethodEventBuilder::indexToWayland(text, cursor), QWaylandInputMethodEventBuilder::indexToWayland(text, anchor));
     }
 
     if (queries & Qt::ImHints) {
diff --git a/src/compositor/extensions/qwaylandtextinput.cpp b/src/compositor/extensions/qwaylandtextinput.cpp
index 2d317dcb0..530627641 100644
--- a/src/compositor/extensions/qwaylandtextinput.cpp
+++ b/src/compositor/extensions/qwaylandtextinput.cpp
@@ -157,8 +157,8 @@ void QWaylandTextInputPrivate::sendInputMethodEvent(QInputMethodEvent *event)
         if (event->replacementStart() <= 0 && (event->replacementLength() >= -event->replacementStart())) {
             const int selectionStart = qMin(currentState->cursorPosition, currentState->anchorPosition);
             const int selectionEnd = qMax(currentState->cursorPosition, currentState->anchorPosition);
-            const int before = currentState->surroundingText.midRef(selectionStart + event->replacementStart(), -event->replacementStart()).toUtf8().size();
-            const int after = currentState->surroundingText.midRef(selectionEnd, event->replacementLength() + event->replacementStart()).toUtf8().size();
+            const int before = QWaylandInputMethodEventBuilder::indexToWayland(currentState->surroundingText, -event->replacementStart(), selectionStart + event->replacementStart());
+            const int after = QWaylandInputMethodEventBuilder::indexToWayland(currentState->surroundingText, event->replacementLength() + event->replacementStart(), selectionEnd);
             send_delete_surrounding_text(focusResource->handle, before, after);
         } else {
             // TODO: Implement this case
@@ -175,8 +175,8 @@ void QWaylandTextInputPrivate::sendInputMethodEvent(QInputMethodEvent *event)
         if (attribute.type == QInputMethodEvent::Selection) {
             afterCommit.cursorPosition = attribute.start;
             afterCommit.anchorPosition = attribute.length;
-            int cursor = afterCommit.surroundingText.midRef(qMin(attribute.start, afterCommit.cursorPosition), qAbs(attribute.start - afterCommit.cursorPosition)).toUtf8().size();
-            int anchor = afterCommit.surroundingText.midRef(qMin(attribute.length, afterCommit.cursorPosition), qAbs(attribute.length - afterCommit.cursorPosition)).toUtf8().size();
+            int cursor = QWaylandInputMethodEventBuilder::indexToWayland(afterCommit.surroundingText, qAbs(attribute.start - afterCommit.cursorPosition), qMin(attribute.start, afterCommit.cursorPosition));
+            int anchor = QWaylandInputMethodEventBuilder::indexToWayland(afterCommit.surroundingText, qAbs(attribute.length - afterCommit.cursorPosition), qMin(attribute.length, afterCommit.cursorPosition));
             send_cursor_position(focusResource->handle,
                                  attribute.start < afterCommit.cursorPosition ? -cursor : cursor,
                                  attribute.length < afterCommit.cursorPosition ? -anchor : anchor);
@@ -185,11 +185,11 @@ void QWaylandTextInputPrivate::sendInputMethodEvent(QInputMethodEvent *event)
     send_commit_string(focusResource->handle, event->commitString());
     foreach (const QInputMethodEvent::Attribute &attribute, event->attributes()) {
         if (attribute.type == QInputMethodEvent::Cursor) {
-            int index = event->preeditString().leftRef(attribute.start).toUtf8().size();
+            int index = QWaylandInputMethodEventBuilder::indexToWayland(event->preeditString(), attribute.start);
             send_preedit_cursor(focusResource->handle, index);
         } else if (attribute.type == QInputMethodEvent::TextFormat) {
-            int start = currentState->surroundingText.leftRef(attribute.start).toUtf8().size();
-            int end = currentState->surroundingText.leftRef(attribute.start + attribute.length).toUtf8().size();
+            int start = QWaylandInputMethodEventBuilder::indexToWayland(currentState->surroundingText, attribute.start);
+            int end = QWaylandInputMethodEventBuilder::indexToWayland(currentState->surroundingText, attribute.start + attribute.length);
             // TODO add support for different stylesQWaylandTextInput
             send_preedit_styling(focusResource->handle, start, end - start, preedit_style_default);
         }
diff --git a/src/shared/qwaylandinputmethodeventbuilder.cpp b/src/shared/qwaylandinputmethodeventbuilder.cpp
index eb527c15a..fe93f5146 100644
--- a/src/shared/qwaylandinputmethodeventbuilder.cpp
+++ b/src/shared/qwaylandinputmethodeventbuilder.cpp
@@ -268,19 +268,24 @@ QWaylandInputMethodContentType QWaylandInputMethodContentType::convert(Qt::Input
     return QWaylandInputMethodContentType{hint, purpose};
 }
 
-int QWaylandInputMethodEventBuilder::indexFromWayland(const QString &str, int utf8Index, int baseIndex)
+int QWaylandInputMethodEventBuilder::indexFromWayland(const QString &text, int length, int base)
 {
-    if (utf8Index == 0)
-        return baseIndex;
+    if (length == 0)
+        return base;
 
-    if (utf8Index < 0) {
-        const QByteArray &utf8 = str.leftRef(baseIndex).toUtf8();
-        return QString::fromUtf8(utf8.left(qMax(utf8.length() + utf8Index, 0))).length();
+    if (length < 0) {
+        const QByteArray &utf8 = text.leftRef(base).toUtf8();
+        return QString::fromUtf8(utf8.left(qMax(utf8.length() + length, 0))).length();
     } else {
-        const QByteArray &utf8 = str.midRef(baseIndex).toUtf8();
-        return QString::fromUtf8(utf8.left(utf8Index)).length() + baseIndex;
+        const QByteArray &utf8 = text.midRef(base).toUtf8();
+        return QString::fromUtf8(utf8.left(length)).length() + base;
     }
 }
 
+int QWaylandInputMethodEventBuilder::indexToWayland(const QString &text, int length, int base)
+{
+    return text.midRef(base, length).toUtf8().size();
+}
+
 QT_END_NAMESPACE
 
diff --git a/src/shared/qwaylandinputmethodeventbuilder.h b/src/shared/qwaylandinputmethodeventbuilder.h
index 188a6a94b..3912afc04 100644
--- a/src/shared/qwaylandinputmethodeventbuilder.h
+++ b/src/shared/qwaylandinputmethodeventbuilder.h
@@ -61,7 +61,8 @@ public:
     QInputMethodEvent buildCommit(const QString &text);
     QInputMethodEvent buildPreedit(const QString &text);
 
-    static int indexFromWayland(const QString &str, int utf8Index, int baseIndex = 0);
+    static int indexFromWayland(const QString &text, int length, int base = 0);
+    static int indexToWayland(const QString &text, int length, int base = 0);
 private:
     QPair<int, int> replacementForDeleteSurrounding();