FancyLineEdit: Add camel case navigation

Use it for search and replace functions as well as for Locator.

The camel case navigation can be switched on / off with
the existing menu Options > Text Editor > Behavior >
Enable Build-in camel case navigation.

Fixes: QTCREATORBUG-21140
Change-Id: I3f2dcafff231366b3c8f08c14514dd8940cca2a0
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

1 files changed, 341 insertions, 0 deletions

diff --git a/src/libs/utils/camelcasecursor.cpp b/src/libs/utils/camelcasecursor.cpp
new file mode 100644
index 0000000000..65e69bd70b
--- /dev/null
+++ b/src/libs/utils/camelcasecursor.cpp
@@ -0,0 +1,341 @@
+/**************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Copyright (C) 2019 Andre Hartmann <aha_1980@gmx.de>
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include "camelcasecursor.h"
+
+#include <QLineEdit>
+#include <QPlainTextEdit>
+
+template<typename C, typename E>
+bool moveCursor(C *cursor, E *edit, QTextCursor::MoveOperation direction, QTextCursor::MoveMode mode);
+
+template<>
+bool moveCursor(QTextCursor *cursor, QPlainTextEdit *, QTextCursor::MoveOperation direction,
+                QTextCursor::MoveMode mode)
+{
+    return cursor->movePosition(direction, mode);
+}
+
+template<typename C>
+bool moveCursor(C *, QLineEdit *edit, QTextCursor::MoveOperation direction, QTextCursor::MoveMode mode)
+{
+    bool mark = (mode == QTextCursor::KeepAnchor);
+    switch (direction) {
+    case QTextCursor::Left:
+        edit->cursorBackward(mark);
+        break;
+    case QTextCursor::WordLeft:
+        edit->cursorWordBackward(mark);
+        break;
+    case QTextCursor::Right:
+        edit->cursorForward(mark);
+        break;
+    case QTextCursor::WordRight:
+        edit->cursorWordForward(mark);
+        break;
+    default:
+        return false;
+    }
+    return edit->cursorPosition() > 0 && edit->cursorPosition() < edit->text().size();
+}
+
+template<typename C, typename E>
+QChar charUnderCursor(C *cursor, E *edit);
+
+template<>
+QChar charUnderCursor(QTextCursor *cursor, QPlainTextEdit *edit)
+{
+    return edit->document()->characterAt(cursor->position());
+}
+
+template<typename C>
+QChar charUnderCursor(C *, QLineEdit *edit)
+{
+    const int pos = edit->cursorPosition();
+    if (pos < 0 || pos >= edit->text().length())
+        return QChar::Null;
+
+    return edit->text().at(pos);
+};
+
+template<typename C, typename E>
+int position(C *cursor, E *edit);
+
+template<>
+int position(QTextCursor *cursor, QPlainTextEdit *)
+{
+    return cursor->position();
+}
+
+template<typename C>
+int position(C *, QLineEdit *edit)
+{
+    return edit->cursorPosition();
+}
+
+enum class Input {
+    Upper,
+    Lower,
+    Underscore,
+    Space,
+    Other
+};
+
+template<typename C, typename E>
+bool camelCaseLeft(C *cursor, E *edit, QTextCursor::MoveMode mode)
+{
+    int state = 0;
+
+    if (!moveCursor(cursor, edit, QTextCursor::Left, mode))
+        return false;
+
+    for (;;) {
+        QChar c = charUnderCursor(cursor, edit);
+        Input input = Input::Other;
+        if (c.isUpper())
+            input = Input::Upper;
+        else if (c.isLower() || c.isDigit())
+            input = Input::Lower;
+        else if (c == '_')
+            input = Input::Underscore;
+        else if (c.isSpace() && c != QChar::ParagraphSeparator)
+            input = Input::Space;
+        else
+            input = Input::Other;
+
+        switch (state) {
+        case 0:
+            switch (input) {
+            case Input::Upper:
+                state = 1;
+                break;
+            case Input::Lower:
+                state = 2;
+                break;
+            case Input::Underscore:
+                state = 3;
+                break;
+            case Input::Space:
+                state = 4;
+                break;
+            default:
+                moveCursor(cursor, edit, QTextCursor::Right, mode);
+                return moveCursor(cursor, edit, QTextCursor::WordLeft, mode);
+            }
+            break;
+        case 1:
+            switch (input) {
+            case Input::Upper:
+                break;
+            default:
+                return moveCursor(cursor, edit, QTextCursor::Right, mode);
+                return true;
+            }
+            break;
+        case 2:
+            switch (input) {
+            case Input::Upper:
+                return true;
+            case Input::Lower:
+                break;
+            default:
+                return moveCursor(cursor, edit, QTextCursor::Right, mode);
+                return true;
+            }
+            break;
+        case 3:
+            switch (input) {
+            case Input::Underscore:
+                break;
+            case Input::Upper:
+                state = 1;
+                break;
+            case Input::Lower:
+                state = 2;
+                break;
+            default:
+                moveCursor(cursor, edit, QTextCursor::Right, mode);
+                return true;
+            }
+            break;
+        case 4:
+            switch (input) {
+            case Input::Space:
+                break;
+            case Input::Upper:
+                state = 1;
+                break;
+            case Input::Lower:
+                state = 2;
+                break;
+            case Input::Underscore:
+                state = 3;
+                break;
+            default:
+                return moveCursor(cursor, edit, QTextCursor::Right, mode);
+                if (position(cursor, edit) == 0)
+                    return true;
+                return moveCursor(cursor, edit, QTextCursor::WordLeft, mode);
+            }
+        }
+
+        if (!moveCursor(cursor, edit, QTextCursor::Left, mode))
+            return true;
+    }
+}
+
+template<typename C, typename E>
+bool camelCaseRight(C *cursor, E *edit, QTextCursor::MoveMode mark)
+{
+    int state = 0;
+
+    for (;;) {
+        QChar c = charUnderCursor(cursor, edit);
+        Input input = Input::Other;
+        if (c.isUpper())
+            input = Input::Upper;
+        else if (c.isLower() || c.isDigit())
+            input = Input::Lower;
+        else if (c == '_')
+            input = Input::Underscore;
+        else if (c.isSpace() && c != QChar::ParagraphSeparator)
+            input = Input::Space;
+        else
+            input = Input::Other;
+
+        switch (state) {
+        case 0:
+            switch (input) {
+            case Input::Upper:
+                state = 4;
+                break;
+            case Input::Lower:
+                state = 1;
+                break;
+            case Input::Underscore:
+                state = 6;
+                break;
+            default:
+                return moveCursor(cursor, edit, QTextCursor::WordRight, mark);
+            }
+            break;
+        case 1:
+            switch (input) {
+            case Input::Upper:
+                return true;
+            case Input::Lower:
+                break;
+            case Input::Underscore:
+                state = 6;
+                break;
+            case Input::Space:
+                state = 7;
+                break;
+            default:
+                return true;
+            }
+            break;
+        case 2:
+            switch (input) {
+            case Input::Upper:
+                break;
+            case Input::Lower:
+                moveCursor(cursor, edit, QTextCursor::Left, mark);
+                return true;
+            case Input::Underscore:
+                state = 6;
+                break;
+            case Input::Space:
+                state = 7;
+                break;
+            default:
+                return true;
+            }
+            break;
+        case 4:
+            switch (input) {
+            case Input::Upper:
+                state = 2;
+                break;
+            case Input::Lower:
+                state = 1;
+                break;
+            case Input::Underscore:
+                state = 6;
+                break;
+            case Input::Space:
+                state = 7;
+                break;
+            default:
+                return true;
+            }
+            break;
+        case 6:
+            switch (input) {
+            case Input::Underscore:
+                break;
+            case Input::Space:
+                state = 7;
+                break;
+            default:
+                return true;
+            }
+            break;
+        case 7:
+            switch (input) {
+            case Input::Space:
+                break;
+            default:
+                return true;
+            }
+            break;
+        }
+        if (!moveCursor(cursor, edit, QTextCursor::Right, mark))
+            return false;
+    }
+}
+
+bool CamelCaseCursor::left(QTextCursor *cursor, QPlainTextEdit *edit, QTextCursor::MoveMode mode)
+{
+    return camelCaseLeft(cursor, edit, mode);
+}
+
+bool CamelCaseCursor::left(QLineEdit *edit, QTextCursor::MoveMode mode)
+{
+    QTextCursor temp;
+    return camelCaseLeft(&temp, edit, mode);
+}
+
+bool CamelCaseCursor::right(QTextCursor *cursor, QPlainTextEdit *edit, QTextCursor::MoveMode mode)
+{
+    return camelCaseRight(cursor, edit, mode);
+}
+
+bool CamelCaseCursor::right(QLineEdit *edit, QTextCursor::MoveMode mode)
+{
+    QTextCursor temp;
+    return camelCaseRight(&temp, edit, mode);
+}