move: log parsers

logparser/v5/pipe/logcount.go

@@ -0,0 +1,36 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+package pipe
+
+import "fmt"
+
+// logCount counts the yielded records.
+type logCount struct {
+	Iterator
+	n int
+}
+
+// Each yields to the inner iterator while counting the records.
+// Reports the record number on an error.
+func (lc *logCount) Each(yield func(Record)) error {
+	err := lc.Iterator.Each(func(r Record) {
+		lc.n++
+		yield(r)
+	})
+
+	if err != nil {
+		// lc.n+1: iterator.each won't call yield on err
+		return fmt.Errorf("record %d: %v", lc.n+1, err)
+	}
+	return nil
+}
+
+// count returns the last read record number.
+func (lc *logCount) count() int {
+	return lc.n
+}