BACKENDS: Add base support for system dialogs

3 files changed, 92 insertions, 0 deletions

diff --git a/common/dialogs.h b/common/dialogs.h
new file mode 100644
index 0000000000..70c4837aa5
--- /dev/null
+++ b/common/dialogs.h
@@ -0,0 +1,60 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program 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 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef COMMON_DIALOG_MANAGER_H
+#define COMMON_DIALOG_MANAGER_H
+
+#include "common/scummsys.h"
+#include "common/str.h"
+
+#if defined(USE_SYSDIALOGS)
+
+namespace Common {
+
+/**
+ * The DialogManager allows GUI code to interact with native system dialogs.
+ */
+class DialogManager {
+public:
+	/**
+	 * Values representing the user response to a dialog
+	 */
+	enum DialogResult {
+		kDialogError = -1,	///< Dialog couldn't be displayed
+		kDialogCancel = 0,	///< User cancelled the dialog (Cancel/No/Close buttons)
+		kDialogOk = 1		///< User confirmed the dialog (OK/Yes buttons)
+	};
+
+	DialogManager() {}
+	virtual ~DialogManager() {}
+
+	/**
+	 * Displays a dialog for selecting a file or folder.
+	 */
+	virtual DialogResult showFileBrowser() { return kDialogError; }
+};
+
+} // End of namespace Common
+
+#endif
+
+#endif // COMMON_DIALOG_MANAGER_H
diff --git a/common/system.cpp b/common/system.cpp
index c8023c8ec2..93cf98c08e 100644
--- a/common/system.cpp
+++ b/common/system.cpp
@@ -29,6 +29,7 @@
 #include "common/str.h"
 #include "common/taskbar.h"
 #include "common/updates.h"
+#include "common/dialogs.h"
 #include "common/textconsole.h"
 
 #include "backends/audiocd/default/default-audiocd.h"
@@ -48,6 +49,9 @@ OSystem::OSystem() {
 #if defined(USE_UPDATES)
 	_updateManager = nullptr;
 #endif
+#if defined(USE_SYSDIALOGS)
+	_dialogManager = nullptr;
+#endif
 	_fsFactory = nullptr;
 	_backendInitialized = false;
 }
@@ -72,6 +76,11 @@ OSystem::~OSystem() {
 	_updateManager = nullptr;
 #endif
 
+#if defined(USE_SYSDIALOGS)
+	delete _dialogManager;
+	_dialogManager = nullptr;
+#endif
+
 	delete _savefileManager;
 	_savefileManager = nullptr;
 
diff --git a/common/system.h b/common/system.h
index 405d6a90a8..01d436e5df 100644
--- a/common/system.h
+++ b/common/system.h
@@ -49,6 +49,9 @@ class TaskbarManager;
 #if defined(USE_UPDATES)
 class UpdateManager;
 #endif
+#if defined(USE_SYSDIALOGS)
+class DialogManager;
+#endif
 class TimerManager;
 class SeekableReadStream;
 class WriteStream;
@@ -179,6 +182,15 @@ protected:
 	Common::UpdateManager *_updateManager;
 #endif
 
+#if defined(USE_SYSDIALOGS)
+	/**
+	 * No default value is provided for _dialogManager by OSystem.
+	 *
+	 * @note _dialogManager is deleted by the OSystem destructor.
+	 */
+	Common::DialogManager *_dialogManager;
+#endif
+
 	/**
 	 * No default value is provided for _fsFactory by OSystem.
 	 *
@@ -1305,6 +1317,17 @@ public:
 	}
 #endif
 
+#if defined(USE_SYSDIALOGS)
+	/**
+	 * Returns the DialogManager, used to handle system dialogs.
+	 *
+	 * @return the DialogManager for the current architecture
+	 */
+	virtual Common::DialogManager *getDialogManager() {
+		return _dialogManager;
+	}
+#endif
+
 	/**
 	 * Returns the FilesystemFactory object, depending on the current architecture.
 	 *