Move ChanPeeker into blobref pkg. Need it elsewhere.

lib/go/camli/blobref/chanpeek.go

@@ -0,0 +1,60 @@
+/*
+Copyright 2011 Google Inc.
+
+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 blobref
+
+// TODO: use Generics if/when available
+type ChanPeeker struct {
+	Ch     <-chan SizedBlobRef
+
+	// A channel should either have a peek value or be closed:
+	peek   *SizedBlobRef
+	closed bool
+}
+
+func (cp *ChanPeeker) Peek() *SizedBlobRef {
+	if cp.closed {
+		return nil
+	}
+	if cp.peek != nil {
+		return cp.peek
+	}
+	v, ok := <-cp.Ch
+	if !ok {
+		cp.closed = true
+		return nil
+	}
+	cp.peek = &v
+	return cp.peek
+}
+
+func (cp *ChanPeeker) Closed() bool {
+	cp.Peek()
+	return cp.closed
+}
+
+func (cp *ChanPeeker) Take() *SizedBlobRef {
+	v := cp.Peek()
+	cp.peek = nil
+	return v
+}
+
+func (cp *ChanPeeker) ConsumeAll() {
+	for !cp.Closed() {
+		cp.Take()
+	}
+}
+

lib/go/camli/client/sync.go

@@ -20,35 +20,6 @@ import (
 	"camli/blobref"
 )
 
-// TODO: use Generics if/when available
-type chanPeeker struct {
-	ch     chan blobref.SizedBlobRef
-	peek   *blobref.SizedBlobRef
-	Closed bool
-}
-
-func (cp *chanPeeker) Peek() *blobref.SizedBlobRef {
-	if cp.Closed {
-		return nil
-	}
-	if cp.peek != nil {
-		return cp.peek
-	}
-	v, ok := <-cp.ch
-	if !ok {
-		cp.Closed = true
-		return nil
-	}
-	cp.peek = &v
-	return cp.peek
-}
-
-func (cp *chanPeeker) Take() *blobref.SizedBlobRef {
-	v := cp.Peek()
-	cp.peek = nil
-	return v
-}
-
 // ListMissingDestinationBlobs reads from 'srcch' and 'dstch' (sorted
 // enumerations of blobs from two blob servers) and sends to
 // 'destMissing' any blobs which appear on the source but not at the
@@ -56,8 +27,8 @@ func (cp *chanPeeker) Take() *blobref.SizedBlobRef {
 func ListMissingDestinationBlobs(destMissing, srcch, dstch chan blobref.SizedBlobRef) {
 	defer close(destMissing)
 
-	src := &chanPeeker{ch: srcch}
-	dst := &chanPeeker{ch: dstch}
+	src := &blobref.ChanPeeker{Ch: srcch}
+	dst := &blobref.ChanPeeker{Ch: dstch}
 
 	for src.Peek() != nil {
 		// If the destination has reached its end, anything