Add book matchers for missing files / missing cover image

cmd/liber/list.go

@@ -26,6 +26,8 @@ func (c *listCommand) Usage() string {
     +incomplete
     +invalid
     +source:<SOURCE>
+    +nofiles
+    +missingcover
 
 `
 }
@@ -44,6 +46,21 @@ func matchSource(source string) func(*liber.Book) bool {
 	}
 }
 
+func matchNoFiles(db *liber.Database) func(*liber.Book) bool {
+	return func(book *liber.Book) bool {
+		f, _ := db.GetBookFiles(book.Id)
+		return len(f) == 0
+	}
+}
+
+func matchMissingCover(book *liber.Book) bool {
+	if book.CoverPath == "" {
+		return true
+	}
+	_, err := os.Stat(book.CoverPath)
+	return err != nil && os.IsNotExist(err)
+}
+
 func matchIncomplete(book *liber.Book) bool {
 	return (book.Metadata != nil && book.Metadata.Complete())
 }
@@ -56,7 +73,7 @@ func matchAll(_ *liber.Book) bool {
 	return true
 }
 
-func (c *listCommand) parseTag(tag string) (func(*liber.Book) bool, error) {
+func (c *listCommand) parseTag(db *liber.Database, tag string) (func(*liber.Book) bool, error) {
 	if strings.HasPrefix(tag, "+source:") {
 		return matchSource(tag[7:]), nil
 	}
@@ -68,6 +85,10 @@ func (c *listCommand) parseTag(tag string) (func(*liber.Book) bool, error) {
 		return matchIncomplete, nil
 	case "+invalid":
 		return matchInvalid, nil
+	case "+nofiles":
+		return matchNoFiles(db), nil
+	case "+missingcover":
+		return matchMissingCover, nil
 	default:
 		return nil, fmt.Errorf("unknown tag '%s'", tag)
 	}
@@ -84,7 +105,7 @@ func (c *listCommand) Execute(ctx context.Context, f *flag.FlagSet, _ ...interfa
 
 	var matchFuncs []func(*liber.Book) bool
 	for _, arg := range f.Args() {
-		f, err := c.parseTag(arg)
+		f, err := c.parseTag(db, arg)
 		if err != nil {
 			log.Printf("error: %v", err)
 			return subcommands.ExitUsageError