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/mesonprojectnodes.cpp

@@ -0,0 +1,61 @@
+// 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 "mesonprojectnodes.h"
+
+#include "mesonbuildconfiguration.h"
+#include "mesonbuildsystem.h"
+#include "mesonpluginconstants.h"
+
+#include <projectexplorer/project.h>
+#include <projectexplorer/target.h>
+
+namespace MesonProjectManager {
+namespace Internal {
+
+MesonProjectNode::MesonProjectNode(const Utils::FilePath &directory)
+    : ProjectExplorer::ProjectNode{directory}
+{
+    setPriority(Node::DefaultProjectPriority + 1000);
+    setIcon(Constants::Icons::MESON);
+    setListInProject(false);
+}
+
+MesonFileNode::MesonFileNode(const Utils::FilePath &file)
+    : ProjectExplorer::ProjectNode{file}
+{
+    setIcon(ProjectExplorer::DirectoryIcon(Constants::Icons::MESON));
+    setListInProject(true);
+}
+
+MesonTargetNode::MesonTargetNode(const Utils::FilePath &directory, const QString &name)
+    : ProjectExplorer::ProjectNode{directory}
+    , m_name{name}
+{
+    setPriority(Node::DefaultProjectPriority + 900);
+    setIcon(":/projectexplorer/images/build.png");
+    setListInProject(false);
+    setShowWhenEmpty(true);
+    setProductType(ProjectExplorer::ProductType::Other);
+}
+
+void MesonTargetNode::build()
+{
+    ProjectExplorer::Project *p = getProject();
+    ProjectExplorer::Target *t = p ? p->activeTarget() : nullptr;
+    if (t)
+        static_cast<MesonBuildSystem *>(t->buildSystem())->mesonBuildConfiguration()->build(m_name);
+}
+
+QString MesonTargetNode::tooltip() const
+{
+    return {};
+}
+
+QString MesonTargetNode::buildKey() const
+{
+    return m_name;
+}
+
+} // namespace Internal
+} // namespace MesonProjectManager