Create wallpaper caching and add namespace

src/mac-desktop.h

@@ -8,5 +8,8 @@
 
 #include <string>
 
-bool ChangeBackground(std::string imageURL);
+namespace MacDesktop {
-bool ResetBackground();
+	void CacheCurrentBackground();
+	bool ChangeBackground(std::string imageURL);
+	bool ResetBackground();
+}

src/mac-desktop.mm

@@ -10,16 +10,25 @@
 #import <Foundation/Foundation.h>
 #import <AppKit/AppKit.h>
 
-bool ChangeBackground(std::string imageURL) {
+NSURL *originalBackground;
+NSDictionary<NSWorkspaceDesktopImageOptionKey, id> *originalOptions;
+
+NSScreen *mainscreen = [NSScreen mainScreen];
+NSWorkspace *sharedworkspace = [NSWorkspace sharedWorkspace];
+
+void MacDesktop::CacheCurrentBackground() {
+	originalBackground = [sharedworkspace desktopImageURLForScreen:mainscreen];
+	originalOptions = [sharedworkspace desktopImageOptionsForScreen:mainscreen];
+}
+
+bool MacDesktop::ChangeBackground(std::string imageURL) {
 	NSURL *URL = [NSURL fileURLWithPath:@(imageURL.c_str())];
-	NSScreen *mainscreen = [NSScreen mainScreen];
-	NSWorkspace *sharedworkspace = [NSWorkspace sharedWorkspace];
 
 	BOOL success = [sharedworkspace setDesktopImageURL:[URL absoluteURL] forScreen:mainscreen options:[sharedworkspace desktopImageOptionsForScreen:mainscreen] error:nil];
 	return (bool)success;
 }
 
-bool ResetBackground() {
+bool MacDesktop::ResetBackground() {
-	// XXX Implement me!
+	BOOL success = [sharedworkspace setDesktopImageURL:originalBackground forScreen:mainscreen options:originalOptions error:nil];
-	return false;
+	return (bool)success;
 }