Meson: Flatten directory hierarchy

Keep tests/ and icons/ but put the rest into the toplevel.

The previous setup was so different from the rest of the bunch that
it regularly stuck out in maintenance tasks.

Change-Id: I69821be6268f69682353a388f6bb1fa343215303
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/mesonprojectmanager/mesonwrapper.cpp

@@ -0,0 +1,76 @@
+// Copyright (C) 2020 Alexis Jeandet.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#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