Loading libunity only in Unity and Pantheon. #3053

Commit 296c800b39 introduced a regression which caused crashes
in some ArchLinux distros when attempting to load or use libunity.

Telegram/SourceFiles/platform/linux/linux_desktop_environment.cpp

@@ -0,0 +1,112 @@
+/*
+This file is part of Telegram Desktop,
+the official desktop version of Telegram messaging app, see https://telegram.org
+
+Telegram Desktop is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+It is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+In addition, as a special exception, the copyright holders give permission
+to link the code of portions of this program with the OpenSSL library.
+
+Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
+Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
+*/
+#include "stdafx.h"
+#include "platform/linux/linux_desktop_environment.h"
+
+namespace Platform {
+namespace DesktopEnvironment {
+namespace {
+
+QString GetEnv(const char *name) {
+	auto result = getenv(name);
+	return result ? QString::fromLatin1(result) : QString();
+}
+
+Type Compute() {
+	auto xdgCurrentDesktop = GetEnv("XDG_CURRENT_DESKTOP").toLower();
+	auto list = xdgCurrentDesktop.split(':', QString::SkipEmptyParts);
+	auto desktopSession = GetEnv("DESKTOP_SESSION").toLower();
+	auto kdeSession = GetEnv("KDE_SESSION_VERSION");
+
+	if (!list.isEmpty()) {
+		if (list.contains("unity")) {
+			// gnome-fallback sessions set XDG_CURRENT_DESKTOP to Unity
+			// DESKTOP_SESSION can be gnome-fallback or gnome-fallback-compiz
+			if (desktopSession.indexOf(qstr("gnome-fallback")) >= 0) {
+				return Type::Gnome;
+			}
+			return Type::Unity;
+		} else if (list.contains("xfce")) {
+			return Type::XFCE;
+		} else if (list.contains("pantheon")) {
+			return Type::Pantheon;
+		} else if (list.contains("gnome")) {
+			return Type::Gnome;
+		} else if (list.contains("kde")) {
+			if (kdeSession == qstr("5")) {
+				return Type::KDE5;
+			}
+			return Type::KDE4;
+		}
+	}
+
+	if (!desktopSession.isEmpty()) {
+		if (desktopSession == qstr("gnome") || desktopSession == qstr("mate")) {
+			return Type::Gnome;
+		} else if (desktopSession == qstr("kde4") || desktopSession == qstr("kde-plasma")) {
+			return Type::KDE4;
+		} else if (desktopSession == qstr("kde")) {
+			// This may mean KDE4 on newer systems, so we have to check.
+			if (!kdeSession.isEmpty()) {
+				return Type::KDE4;
+			}
+			return Type::KDE3;
+		} else if (desktopSession.indexOf(qstr("xfce")) >= 0 || desktopSession == qstr("xubuntu")) {
+			return Type::XFCE;
+		}
+	}
+
+	// Fall back on some older environment variables.
+	// Useful particularly in the DESKTOP_SESSION=default case.
+	if (!GetEnv("GNOME_DESKTOP_SESSION_ID").isEmpty()) {
+		return Type::Gnome;
+	} else if (!GetEnv("KDE_FULL_SESSION").isEmpty()) {
+		if (!kdeSession.isEmpty()) {
+			return Type::KDE4;
+		}
+		return Type::KDE3;
+	}
+
+	return Type::Other;
+}
+
+} // namespace
+
+// Thanks Chromium.
+Type Get() {
+	static const auto result = Compute();
+	return result;
+}
+
+bool TryQtTrayIcon() {
+	return !IsPantheon() && !IsGnome();
+}
+
+bool PreferAppIndicatorTrayIcon() {
+	return IsXFCE() || IsUnity();
+}
+
+bool TryUnityCounter() {
+	return IsUnity() || IsPantheon();
+}
+
+} // namespace DesktopEnvironment
+} // namespace Platform