TextEditor: move convenience from texteditor to utils

Allows to use this header without texteditor dependency.

Change-Id: I706f42799c3ea42473a716fa9ef9f3cfbef6fdd4
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/libs/utils/textutils.cpp

@@ -0,0 +1,125 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** 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 "textutils.h"
+
+#include <QTextDocument>
+#include <QTextBlock>
+#include <QTextCursor>
+
+namespace Utils {
+namespace Text {
+
+bool convertPosition(const QTextDocument *document, int pos, int *line, int *column)
+{
+    QTextBlock block = document->findBlock(pos);
+    if (!block.isValid()) {
+        (*line) = -1;
+        (*column) = -1;
+        return false;
+    } else {
+        (*line) = block.blockNumber() + 1;
+        (*column) = pos - block.position();
+        return true;
+    }
+}
+
+QString textAt(QTextCursor tc, int pos, int length)
+{
+    if (pos < 0)
+        pos = 0;
+    tc.movePosition(QTextCursor::End);
+    if (pos + length > tc.position())
+        length = tc.position() - pos;
+
+    tc.setPosition(pos);
+    tc.setPosition(pos + length, QTextCursor::KeepAnchor);
+
+    // selectedText() returns U+2029 (PARAGRAPH SEPARATOR) instead of newline
+    return tc.selectedText().replace(QChar::ParagraphSeparator, QLatin1Char('\n'));
+}
+
+QTextCursor selectAt(QTextCursor textCursor, uint line, uint column, uint length)
+{
+    if (line < 1)
+        line = 1;
+
+    if (column < 1)
+        column = 1;
+
+    textCursor.setPosition(0);
+    textCursor.movePosition(QTextCursor::NextBlock, QTextCursor::MoveAnchor, line - 1);
+    textCursor.movePosition(QTextCursor::NextCharacter,QTextCursor::MoveAnchor, column  + length - 1 );
+
+    textCursor.movePosition(QTextCursor::PreviousCharacter,QTextCursor::KeepAnchor, length);
+
+    return textCursor;
+}
+
+QTextCursor flippedCursor(const QTextCursor &cursor)
+{
+    QTextCursor flipped = cursor;
+    flipped.clearSelection();
+    flipped.setPosition(cursor.anchor(), QTextCursor::KeepAnchor);
+    return flipped;
+}
+
+static bool isValidIdentifierChar(const QChar &c)
+{
+    return c.isLetter()
+        || c.isNumber()
+        || c == QLatin1Char('_')
+        || c.isHighSurrogate()
+        || c.isLowSurrogate();
+}
+
+static bool isAfterOperatorKeyword(QTextCursor cursor)
+{
+    cursor.movePosition(QTextCursor::PreviousWord);
+    cursor.movePosition(QTextCursor::EndOfWord, QTextCursor::KeepAnchor);
+    return cursor.selectedText() == "operator";
+}
+
+QTextCursor wordStartCursor(const QTextCursor &textCursor)
+{
+    const int originalPosition = textCursor.position();
+    QTextCursor cursor(textCursor);
+    cursor.movePosition(QTextCursor::StartOfWord);
+    const int wordStartPosition = cursor.position();
+
+    if (originalPosition == wordStartPosition) {
+        // Cursor is not on an identifier, check whether we are right after one.
+        const QChar c = textCursor.document()->characterAt(originalPosition - 1);
+        if (isValidIdentifierChar(c))
+            cursor.movePosition(QTextCursor::PreviousWord);
+    }
+    if (isAfterOperatorKeyword(cursor))
+        cursor.movePosition(QTextCursor::PreviousWord);
+
+    return cursor;
+}
+
+} // Text
+} // Utils