Meson build plugin initial support

Most basic project management is implemented:
- Project config/build
- Build options accessible to user
- Lists most build targets
- Meson and Ninja added to kit setup
- Basic project file tree with files known by Meson
- Some basic meson and ninja process output parsing
- Some project templates

Missing features, that will come later:
- Configurable project tree layout
- Locators for Meson
- Build importer
- Access to Machine files for better user fine tuning
- ...

Fixes: QTCREATORBUG-18117
Change-Id: I2811e71562c113fb0fc6b6177bcf0698fa71ef63
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/mesonprojectmanager/project/buildoptions/optionsmodel/arrayoptionlineedit.cpp

@@ -0,0 +1,88 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Alexis Jeandet.
+** 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 "arrayoptionlineedit.h"
+namespace MesonProjectManager {
+namespace Internal {
+ArrayOptionLineEdit::ArrayOptionLineEdit(QWidget *parent)
+    : QPlainTextEdit(parent)
+{
+    m_highLighter = new RegexHighlighter(this);
+    m_highLighter->setDocument(this->document());
+    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    setLineWrapMode(QPlainTextEdit::NoWrap);
+    QFontMetrics metrics(this->font());
+    int lineHeight = metrics.lineSpacing();
+    this->setFixedHeight(lineHeight * 1.5);
+}
+
+QStringList ArrayOptionLineEdit::options()
+{
+    return m_highLighter->options(this->toPlainText());
+}
+
+void ArrayOptionLineEdit::keyPressEvent(QKeyEvent *e)
+{
+    if (e->key() != Qt::Key_Return)
+        return QPlainTextEdit::keyPressEvent(e);
+    e->accept();
+}
+
+RegexHighlighter::RegexHighlighter(QWidget *parent)
+    : QSyntaxHighlighter(parent)
+{
+    m_format.setUnderlineStyle(QTextCharFormat::SingleUnderline);
+    m_format.setUnderlineColor(QColor(180, 180, 180));
+    m_format.setBackground(QBrush(QColor(180, 180, 230, 80)));
+}
+
+QStringList RegexHighlighter::options(const QString &text)
+{
+    QRegularExpressionMatchIterator i = m_regex.globalMatch(text);
+    QStringList op;
+    while (i.hasNext()) {
+        QRegularExpressionMatch match = i.next();
+        for (int j = 1; j <= match.lastCapturedIndex(); j++) {
+            auto str = match.captured(j);
+            if (!str.isEmpty())
+                op.push_back(str);
+        }
+    }
+    return op;
+}
+
+void RegexHighlighter::highlightBlock(const QString &text)
+{
+    QRegularExpressionMatchIterator i = m_regex.globalMatch(text);
+    while (i.hasNext()) {
+        QRegularExpressionMatch match = i.next();
+        for (int j = 1; j <= match.lastCapturedIndex(); j++) {
+            setFormat(match.capturedStart(j), match.capturedLength(j), m_format);
+        }
+    }
+}
+} // namespace Internal
+} // namespace MesonProjectManager