docker-plugin: fix daemon state

Changed daemon state to actually check the docker runtime to determine
if its available or not.

Change-Id: I9e183658dfc7c34e229aec2a332cf303793284e5
Reviewed-by: hjk <hjk@qt.io>

src/plugins/docker/dockerapi.h

@@ -0,0 +1,68 @@
+/****************************************************************************
+**
+** Copyright (C) 2022 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.
+**
+****************************************************************************/
+
+#pragma once
+
+#include <QMutex>
+#include <QObject>
+
+#include <utils/filepath.h>
+#include <utils/guard.h>
+#include <utils/optional.h>
+
+namespace Docker {
+namespace Internal {
+
+class DockerApi : public QObject
+{
+    Q_OBJECT
+
+public:
+    DockerApi();
+
+    static DockerApi *instance();
+
+    bool canConnect();
+    void checkCanConnect();
+    static void recheckDockerDaemon();
+
+signals:
+    void dockerDaemonAvailableChanged();
+
+public:
+    Utils::optional<bool> dockerDaemonAvailable();
+    static Utils::optional<bool> isDockerDaemonAvailable();
+
+private:
+    Utils::FilePath findDockerClient();
+
+private:
+    Utils::FilePath m_dockerExecutable;
+    Utils::optional<bool> m_dockerDaemonAvailable;
+    QMutex m_daemonCheckGuard;
+};
+
+} // namespace Internal
+} // namespace Docker