use exif-terminator

vendor/github.com/dsoprea/go-utility/v2/filesystem/graceful_copy.go

@@ -0,0 +1,54 @@
+package rifs
+
+import (
+	"fmt"
+	"io"
+)
+
+const (
+	defaultCopyBufferSize = 1024 * 1024
+)
+
+// GracefulCopy willcopy while enduring lesser normal issues.
+//
+// - We'll ignore EOF if the read byte-count is more than zero. Only an EOF when
+//   zero bytes were read will terminate the loop.
+//
+// - Ignore short-writes. If less bytes were written than the bytes that were
+//   given, we'll keep trying until done.
+func GracefulCopy(w io.Writer, r io.Reader, buffer []byte) (copyCount int, err error) {
+	if buffer == nil {
+		buffer = make([]byte, defaultCopyBufferSize)
+	}
+
+	for {
+		readCount, err := r.Read(buffer)
+		if err != nil {
+			if err != io.EOF {
+				err = fmt.Errorf("read error: %s", err.Error())
+				return 0, err
+			}
+
+			// Only break on EOF if no bytes were actually read.
+			if readCount == 0 {
+				break
+			}
+		}
+
+		writeBuffer := buffer[:readCount]
+
+		for len(writeBuffer) > 0 {
+			writtenCount, err := w.Write(writeBuffer)
+			if err != nil {
+				err = fmt.Errorf("write error: %s", err.Error())
+				return 0, err
+			}
+
+			writeBuffer = writeBuffer[writtenCount:]
+		}
+
+		copyCount += readCount
+	}
+
+	return copyCount, nil
+}