Add the ability to ignore types to FaviconURLFinder, and ignore SVG favicons

Shared/Favicons/FaviconDownloader.swift

@@ -208,7 +208,9 @@ private extension FaviconDownloader {
 			return
 		}
 
-		FaviconURLFinder.findFaviconURLs(homePageURL) { (faviconURLs) in
+		let ignoredTypes = [kUTTypeScalableVectorGraphics as String]
+
+		FaviconURLFinder.findFaviconURLs(with: homePageURL, ignoredTypes: ignoredTypes) { (faviconURLs) in
 			var defaultFaviconURL: String? = nil
 
 			if let scheme = url.scheme, let host = url.host {

Shared/Favicons/FaviconURLFinder.swift

@@ -13,15 +13,50 @@ import RSParser
 
 struct FaviconURLFinder {
 
-	static func findFaviconURLs(_ homePageURL: String, _ completion: @escaping ([String]?) -> Void) {
+	/// Finds favicon URLs in a web page.
+	/// - Parameters:
+	///   - homePageURL: The page to search.
+	///   - ignoredTypes: An array of uniform type identifiers to ignore.
+	///   - completion: A closure called when the links have been found.
+	///   - urls: An array of favicon URLs as strings.
+	static func findFaviconURLs(with homePageURL: String, ignoredTypes ignoredTypes: [String]? = nil, _ completion: @escaping (_ urls:[String]?) -> Void) {
 
 		guard let _ = URL(string: homePageURL) else {
 			completion(nil)
 			return
 		}
 
+		var ignoredMimeTypes = [String]()
+		var ignoredExtensions = [String]()
+
+		if let ignoredTypes = ignoredTypes {
+			for type in ignoredTypes {
+				if let mimeTypes = UTTypeCopyAllTagsWithClass(type as CFString, kUTTagClassMIMEType)?.takeRetainedValue() {
+					ignoredMimeTypes.append(contentsOf: mimeTypes as! [String])
+				}
+				if let extensions = UTTypeCopyAllTagsWithClass(type as CFString, kUTTagClassFilenameExtension)?.takeRetainedValue() {
+					ignoredExtensions.append(contentsOf: extensions as! [String])
+				}
+			}
+		}
+
+		// If the favicon has an explicit type, check that for an ignored type; otherwise, check the file extension.
 		HTMLMetadataDownloader.downloadMetadata(for: homePageURL) { (htmlMetadata) in
-			completion(htmlMetadata?.faviconLinks)
+			let faviconURLs = htmlMetadata?.faviconLinks.filter({ (faviconLink) -> Bool in
+				if faviconLink.type != nil {
+					if ignoredMimeTypes.contains(faviconLink.type) {
+						return false
+					}
+				} else {
+					if let url = URL(string: faviconLink.urlString!), ignoredExtensions.contains(url.pathExtension) {
+						return false
+					}
+				}
+
+				return true
+			}).map { $0.urlString! }
+
+			completion(faviconURLs)
 		}
 	}
 }