Fix incomplete local hashes.

Fixes #533

fs/hash.go

@@ -117,8 +117,9 @@ func hashToMultiWriter(h map[HashType]hash.Hash) io.Writer {
 // A MultiHasher will construct various hashes on
 // all incoming writes.
 type MultiHasher struct {
-	io.Writer
-	h map[HashType]hash.Hash // Hashes
+	w    io.Writer
+	size int64
+	h    map[HashType]hash.Hash // Hashes
 }
 
 // NewMultiHasher will return a hash writer that will write all
@@ -138,10 +139,16 @@ func NewMultiHasherTypes(set HashSet) (*MultiHasher, error) {
 	if err != nil {
 		return nil, err
 	}
-	m := MultiHasher{h: hashers, Writer: hashToMultiWriter(hashers)}
+	m := MultiHasher{h: hashers, w: hashToMultiWriter(hashers)}
 	return &m, nil
 }
 
+func (m *MultiHasher) Write(p []byte) (n int, err error) {
+	n, err = m.w.Write(p)
+	m.size += int64(n)
+	return n, err
+}
+
 // Sums returns the sums of all accumulated hashes as hex encoded
 // strings.
 func (m *MultiHasher) Sums() map[HashType]string {
@@ -152,6 +159,11 @@ func (m *MultiHasher) Sums() map[HashType]string {
 	return dst
 }
 
+// Size returns the number of bytes written
+func (m *MultiHasher) Size() int64 {
+	return m.size
+}
+
 // A HashSet Indicates one or more hash types.
 type HashSet int
 

local/local.go

@@ -566,13 +566,13 @@ func (file *localOpenFile) Read(p []byte) (n int, err error) {
 	return
 }
 
-// Close the object and update the md5sum
+// Close the object and update the hashes
 func (file *localOpenFile) Close() (err error) {
 	err = file.in.Close()
 	if err == nil {
-		file.o.hashes = file.hash.Sums()
-	} else {
-		file.o.hashes = nil
+		if file.hash.Size() == file.o.Size() {
+			file.o.hashes = file.hash.Sums()
+		}
 	}
 	return err
 }