rename all remaining packages to internal/ (#12418)

This is to ensure that there are no projects
that try to import `minio/minio/pkg` into
their own repo. Any such common packages should
go to `https://github.com/minio/pkg`

internal/ioutil/wait_pipe.go

@@ -0,0 +1,64 @@
+// Copyright (c) 2015-2021 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package ioutil
+
+import (
+	"io"
+	"sync"
+)
+
+// PipeWriter is similar to io.PipeWriter with wait group
+type PipeWriter struct {
+	*io.PipeWriter
+	done func()
+}
+
+// CloseWithError close with supplied error the writer end.
+func (w *PipeWriter) CloseWithError(err error) error {
+	err = w.PipeWriter.CloseWithError(err)
+	w.done()
+	return err
+}
+
+// PipeReader is similar to io.PipeReader with wait group
+type PipeReader struct {
+	*io.PipeReader
+	wait func()
+}
+
+// CloseWithError close with supplied error the reader end
+func (r *PipeReader) CloseWithError(err error) error {
+	err = r.PipeReader.CloseWithError(err)
+	r.wait()
+	return err
+}
+
+// WaitPipe implements wait-group backend io.Pipe to provide
+// synchronization between read() end with write() end.
+func WaitPipe() (*PipeReader, *PipeWriter) {
+	r, w := io.Pipe()
+	var wg sync.WaitGroup
+	wg.Add(1)
+	return &PipeReader{
+			PipeReader: r,
+			wait:       wg.Wait,
+		}, &PipeWriter{
+			PipeWriter: w,
+			done:       wg.Done,
+		}
+}