ClangFormat: Refactor indenter to allow ClangFormat unit-tests

We do not build texteditor files in unit-tests so some tricks
were required to make ClangFormatIndenter available.

First simple unit-test proofs it builds and runs.

Change-Id: I81d5ea099bd27fd1c1ed8b5b7877299dcc62a67f
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/plugins/texteditor/textindenter.cpp

@@ -0,0 +1,114 @@
+/****************************************************************************
+**
+** 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 "textindenter.h"
+
+#include <QTextDocument>
+#include <QTextCursor>
+
+using namespace TextEditor;
+
+TextIndenter::TextIndenter(QTextDocument *doc)
+    : Indenter(doc)
+{}
+
+TextIndenter::~TextIndenter() = default;
+
+IndentationForBlock TextIndenter::indentationForBlocks(const QVector<QTextBlock> &blocks,
+                                                       const TabSettings &tabSettings)
+{
+    IndentationForBlock ret;
+    for (QTextBlock block : blocks)
+        ret.insert(block.blockNumber(), indentFor(block, tabSettings));
+    return ret;
+}
+
+void TextIndenter::indentBlock(const QTextBlock &block,
+                               const QChar &typedChar,
+                               const TabSettings &tabSettings)
+{
+    Q_UNUSED(typedChar);
+    const int indent = indentFor(block, tabSettings);
+    if (indent < 0)
+        return;
+    tabSettings.indentLine(block, indent);
+}
+
+void TextIndenter::indent(const QTextCursor &cursor,
+                          const QChar &typedChar,
+                          const TabSettings &tabSettings)
+{
+    if (cursor.hasSelection()) {
+        QTextBlock block = m_doc->findBlock(cursor.selectionStart());
+        const QTextBlock end = m_doc->findBlock(cursor.selectionEnd()).next();
+        do {
+            indentBlock(block, typedChar, tabSettings);
+            block = block.next();
+        } while (block.isValid() && block != end);
+    } else {
+        indentBlock(cursor.block(), typedChar, tabSettings);
+    }
+}
+
+void TextIndenter::reindent(const QTextCursor &cursor, const TabSettings &tabSettings)
+{
+    if (cursor.hasSelection()) {
+        QTextBlock block = m_doc->findBlock(cursor.selectionStart());
+        const QTextBlock end = m_doc->findBlock(cursor.selectionEnd()).next();
+
+        // skip empty blocks
+        while (block.isValid() && block != end) {
+            QString bt = block.text();
+            if (tabSettings.firstNonSpace(bt) < bt.size())
+                break;
+            indentBlock(block, QChar::Null, tabSettings);
+            block = block.next();
+        }
+
+        int previousIndentation = tabSettings.indentationColumn(block.text());
+        indentBlock(block, QChar::Null, tabSettings);
+        int currentIndentation = tabSettings.indentationColumn(block.text());
+        int delta = currentIndentation - previousIndentation;
+
+        block = block.next();
+        while (block.isValid() && block != end) {
+            tabSettings.reindentLine(block, delta);
+            block = block.next();
+        }
+    } else {
+        indentBlock(cursor.block(), QChar::Null, tabSettings);
+    }
+}
+
+Replacements TextIndenter::format(const QTextCursor &cursor, const TabSettings &tabSettings)
+{
+    indent(cursor, QChar::Null, tabSettings);
+    return Replacements();
+}
+
+Utils::optional<TabSettings> TextIndenter::tabSettings() const
+{
+    return Utils::optional<TabSettings>();
+}