added custom buffer size error handling

pkg/fs/discard.go

@@ -0,0 +1,60 @@
+// Copyright (C) 2022 Marius Schellenberger
+
+package fs
+
+import (
+	"io"
+	"sync"
+)
+
+var Discard io.Writer = discard{}
+
+type discard struct{}
+
+var _ io.ReaderFrom = discard{}
+
+func (discard) Write(p []byte) (int, error) {
+	return len(p), nil
+}
+
+func (discard) WriteString(s string) (int, error) {
+	return len(s), nil
+}
+
+const DefaultBufferSize = 8192
+
+var blackHolePool = sync.Pool{
+	New: func() any {
+		b := make([]byte, DefaultBufferSize)
+		return &b
+	},
+}
+
+func SetBufferSize(size int) bool {
+	if size < 0 || size == DefaultBufferSize {
+		return false
+	}
+	blackHolePool = sync.Pool{
+		New: func() any {
+			b := make([]byte, size)
+			return &b
+		},
+	}
+	return true
+}
+
+func (discard) ReadFrom(r io.Reader) (n int64, err error) {
+	bufp := blackHolePool.Get().(*[]byte)
+	readSize := 0
+	for {
+		readSize, err = r.Read(*bufp)
+		n += int64(readSize)
+		if err != nil {
+			blackHolePool.Put(bufp)
+			if err == io.EOF {
+				return n, nil
+			}
+			return
+		}
+	}
+}