1 files changed, 69 insertions, 0 deletions
diff --git a/pkg/v1/remote/progress.go b/pkg/v1/remote/progress.go
new file mode 100644
index 0000000..1f43963
--- /dev/null
+++ b/pkg/v1/remote/progress.go
@@ -0,0 +1,69 @@
+// Copyright 2022 Google LLC All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package remote
+
+import (
+	"io"
+	"sync"
+	"sync/atomic"
+
+	v1 "github.com/google/go-containerregistry/pkg/v1"
+)
+
+type progress struct {
+	sync.Mutex
+	updates    chan<- v1.Update
+	lastUpdate *v1.Update
+}
+
+func (p *progress) total(delta int64) {
+	atomic.AddInt64(&p.lastUpdate.Total, delta)
+}
+
+func (p *progress) complete(delta int64) {
+	p.Lock()
+	defer p.Unlock()
+	p.updates <- v1.Update{
+		Total:    p.lastUpdate.Total,
+		Complete: atomic.AddInt64(&p.lastUpdate.Complete, delta),
+	}
+}
+
+func (p *progress) err(err error) error {
+	if err != nil && p.updates != nil {
+		p.updates <- v1.Update{Error: err}
+	}
+	return err
+}
+
+type progressReader struct {
+	rc io.ReadCloser
+
+	count    *int64 // number of bytes this reader has read, to support resetting on retry.
+	progress *progress
+}
+
+func (r *progressReader) Read(b []byte) (int, error) {
+	n, err := r.rc.Read(b)
+	if err != nil {
+		return n, err
+	}
+	atomic.AddInt64(r.count, int64(n))
+	// TODO: warn/debug log if sending takes too long, or if sending is blocked while context is canceled.
+	r.progress.complete(int64(n))
+	return n, nil
+}
+
+func (r *progressReader) Close() error { return r.rc.Close() }