When an invalid zip file is found, instead of ignoring it silently, log

a warning message

Author: hkalexling

src/library.cr

@@ -61,9 +61,9 @@ end
 
 class Title
 	JSON.mapping dir: String, entries: Array(Entry), title: String,
-		id: String, encoded_title: String, mtime: Time
+		id: String, encoded_title: String, mtime: Time, logger: MLogger
 
-	def initialize(dir : String, storage)
+	def initialize(dir : String, storage, @logger : MLogger)
 		@dir = dir
 		@id = storage.get_id @dir, true
 		@title = File.basename dir
@@ -91,6 +91,8 @@ class Title
 			file.close
 			return true
 		rescue
+			@logger.warn "File #{path} is corrupted or is not a valid zip "\
+				"archive. Ignoring it."
 			return false
 		end
 	end
@@ -200,7 +202,7 @@ class Library
 		end
 		@titles = (Dir.entries @dir)
 			.select { |path| File.directory? File.join @dir, path }
-			.map { |path| Title.new File.join(@dir, path), @storage }
+			.map { |path| Title.new File.join(@dir, path), @storage, @logger }
 			.select { |title| !title.entries.empty? }
 			.sort { |a, b| a.title <=> b.title }
 		@logger.debug "Scan completed"