Feature/check latest version (#876)

* Log latest version information

include/openspace/engine/configuration.h

@@ -65,6 +65,7 @@ struct Configuration {
     };
     DocumentationInfo documentation;
 
+    std::string versionCheckUrl;
     bool useMultithreadedInitialization = false;
 
     struct LoadingScreen {

include/openspace/engine/globals.h

@@ -46,6 +46,7 @@ class RenderEngine;
 class ScreenSpaceRenderable;
 class SyncEngine;
 class TimeManager;
+class VersionChecker;
 class VirtualPropertyManager;
 struct WindowDelegate;
 namespace configuration { struct Configuration; }
@@ -81,6 +82,7 @@ RenderEngine& gRenderEngine();
 std::vector<std::unique_ptr<ScreenSpaceRenderable>>& gScreenspaceRenderables();
 SyncEngine& gSyncEngine();
 TimeManager& gTimeManager();
+VersionChecker& gVersionChecker();
 VirtualPropertyManager& gVirtualPropertyManager();
 WindowDelegate& gWindowDelegate();
 configuration::Configuration& gConfiguration();
@@ -112,6 +114,7 @@ static std::vector<std::unique_ptr<ScreenSpaceRenderable>>& screenSpaceRenderabl
     detail::gScreenspaceRenderables();
 static SyncEngine& syncEngine = detail::gSyncEngine();
 static TimeManager& timeManager = detail::gTimeManager();
+static VersionChecker& versionChecker = detail::gVersionChecker();
 static VirtualPropertyManager& virtualPropertyManager = detail::gVirtualPropertyManager();
 static WindowDelegate& windowDelegate = detail::gWindowDelegate();
 static configuration::Configuration& configuration = detail::gConfiguration();

include/openspace/engine/openspaceengine.h

@@ -28,6 +28,7 @@
 #include <openspace/properties/stringproperty.h>
 #include <openspace/util/keys.h>
 #include <openspace/util/mouse.h>
+#include <openspace/util/versionchecker.h>
 #include <ghoul/glm.h>
 #include <memory>
 #include <string>
@@ -109,6 +110,7 @@ private:
     std::unique_ptr<Scene> _scene;
     std::unique_ptr<AssetManager> _assetManager;
     std::unique_ptr<LoadingScreen> _loadingScreen;
+    std::unique_ptr<VersionChecker> _versionChecker;
 
     bool _hasScheduledAssetLoading = false;
     std::string _scheduledAssetPathToLoad;

include/openspace/util/versionchecker.h

@@ -0,0 +1,58 @@
+/*****************************************************************************************
+ *                                                                                       *
+ * OpenSpace                                                                             *
+ *                                                                                       *
+ * Copyright (c) 2014-2019                                                               *
+ *                                                                                       *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
+ * software and associated documentation files (the "Software"), to deal in the Software *
+ * without restriction, including without limitation the rights to use, copy, modify,    *
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to    *
+ * permit persons to whom the Software is furnished to do so, subject to the following   *
+ * conditions:                                                                           *
+ *                                                                                       *
+ * The above copyright notice and this permission notice shall be included in all copies *
+ * or substantial portions of the Software.                                              *
+ *                                                                                       *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   *
+ * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         *
+ * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT    *
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF  *
+ * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE  *
+ * OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                                         *
+ ****************************************************************************************/
+
+#ifndef __OPENSPACE_CORE___VERSIONCHECKER___H__
+#define __OPENSPACE_CORE___VERSIONCHECKER___H__
+
+#include <openspace/util/httprequest.h>
+#include <memory>
+#include <optional>
+#include <string>
+
+namespace openspace {
+
+
+class VersionChecker {
+public:
+    struct SemanticVersion {
+        int major;
+        int minor;
+        int patch;
+    };
+
+    void requestLatestVersion(const std::string& url);
+    bool hasLatestVersionInfo();
+    SemanticVersion latestVersion();
+
+private:
+    std::unique_ptr<AsyncHttpMemoryDownload> _request;
+    std::optional<SemanticVersion> _latestVersion;
+};
+
+bool operator<(const VersionChecker::SemanticVersion a,
+    const VersionChecker::SemanticVersion b);
+
+} // namespace openspace
+
+#endif // __OPENSPACE_CORE___VERSIONCHECKER___H__