feat: QLOPML extension

QLOPML/PreviewViewController.m

@@ -0,0 +1,27 @@
+#import "PreviewViewController.h"
+#import <Quartz/Quartz.h>
+#import <WebKit/WebKit.h>
+#include "opml-lib.h"
+
+@interface PreviewViewController () <QLPreviewingController>
+@end
+
+@implementation PreviewViewController
+
+- (NSString *)nibName {
+	return @"PreviewViewController";
+}
+
+- (void)preparePreviewOfFileAtURL:(NSURL *)url completionHandler:(void (^)(NSError * _Nullable))handler {
+	NSData *data = generateHTMLData(url, [NSBundle mainBundle], NO);
+	// sure, we could use `WKWebView`, but that requires the `com.apple.security.network.client` entitlement
+	WebView *web = [[WebView alloc] initWithFrame:self.view.bounds];
+	web.autoresizingMask = NSViewWidthSizable | NSViewHeightSizable;
+	[self.view addSubview:web];
+//	[web.mainFrame loadHTMLString:html baseURL:nil];
+	[web.mainFrame loadData:data MIMEType:@"text/html" textEncodingName:@"UTF-8" baseURL:nil];
+	handler(nil);
+}
+
+@end
+