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/exewrappers/mesonwrapper.cpp

@@ -0,0 +1,96 @@
+/****************************************************************************
+**
+** 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 "mesonwrapper.h"
+#include "utils/algorithm.h"
+#include "utils/qtcassert.h"
+#include <QUuid>
+
+namespace {
+template<typename First>
+void impl_option_cat(QStringList &list, const First &first)
+{
+    list.append(first);
+}
+
+template<typename First, typename... T>
+void impl_option_cat(QStringList &list, const First &first, const T &... args)
+{
+    impl_option_cat(list, first);
+    impl_option_cat(list, args...);
+}
+
+template<typename... T>
+QStringList options_cat(const T &... args)
+{
+    QStringList result;
+    impl_option_cat(result, args...);
+    return result;
+}
+
+} // namespace
+namespace MesonProjectManager {
+namespace Internal {
+
+Command MesonWrapper::setup(const Utils::FilePath &sourceDirectory,
+                            const Utils::FilePath &buildDirectory,
+                            const QStringList &options) const
+{
+    return {m_exe,
+            sourceDirectory,
+            options_cat("setup", options, sourceDirectory.toString(), buildDirectory.toString())};
+}
+
+Command MesonWrapper::configure(const Utils::FilePath &sourceDirectory,
+                                const Utils::FilePath &buildDirectory,
+                                const QStringList &options) const
+{
+    if (!isSetup(buildDirectory))
+        return setup(sourceDirectory, buildDirectory, options);
+    return {m_exe, buildDirectory, options_cat("configure", options, buildDirectory.toString())};
+}
+
+Command MesonWrapper::regenerate(const Utils::FilePath &sourceDirectory,
+                                 const Utils::FilePath &buildDirectory) const
+{
+    return {m_exe,
+            buildDirectory,
+            options_cat("--internal",
+                        "regenerate",
+                        sourceDirectory.toString(),
+                        buildDirectory.toString(),
+                        "--backend",
+                        "ninja")};
+}
+
+Command MesonWrapper::introspect(const Utils::FilePath &sourceDirectory) const
+{
+    return {m_exe,
+            sourceDirectory,
+            {"introspect", "--all", QString("%1/meson.build").arg(sourceDirectory.toString())}};
+}
+
+} // namespace Internal
+} // namespace MesonProjectManager