Bump to Buildah 1.16.0-dev in upstream

Bump Buildah to v1.16.0-dev in the upstream branch
of Podman.  This will allow us to get a number of new
issues into the upstream branch for use.  The version of
Buildah will need to be bumped to v1.16.0 and then
vendored into Podman before we release Podman v2.0

Signed-off-by: TomSweeneyRedHat <tsweeney@redhat.com>

vendor/github.com/containers/buildah/digester.go

@@ -1,63 +1,255 @@
 package buildah
 
 import (
+	"archive/tar"
+	"fmt"
 	"hash"
-	"strings"
+	"io"
+	"sync"
 
 	digest "github.com/opencontainers/go-digest"
+	"github.com/pkg/errors"
 )
 
-type singleDigester struct {
-	digester digest.Digester
-	prefix   string
+type digester interface {
+	io.WriteCloser
+	ContentType() string
+	Digest() digest.Digest
+}
+
+// A simple digester just digests its content as-is.
+type simpleDigester struct {
+	digester    digest.Digester
+	hasher      hash.Hash
+	contentType string
+}
+
+func newSimpleDigester(contentType string) digester {
+	finalDigester := digest.Canonical.Digester()
+	return &simpleDigester{
+		digester:    finalDigester,
+		hasher:      finalDigester.Hash(),
+		contentType: contentType,
+	}
+}
+
+func (s *simpleDigester) ContentType() string {
+	return s.contentType
+}
+
+func (s *simpleDigester) Write(p []byte) (int, error) {
+	return s.hasher.Write(p)
+}
+
+func (s *simpleDigester) Close() error {
+	return nil
+}
+
+func (s *simpleDigester) Digest() digest.Digest {
+	return s.digester.Digest()
+}
+
+// A tarFilterer passes a tarball through to an io.WriteCloser, potentially
+// modifying headers as it goes.
+type tarFilterer struct {
+	wg         sync.WaitGroup
+	pipeWriter *io.PipeWriter
+	closedLock sync.Mutex
+	closed     bool
+	err        error
+}
+
+func (t *tarFilterer) Write(p []byte) (int, error) {
+	return t.pipeWriter.Write(p)
+}
+
+func (t *tarFilterer) Close() error {
+	t.closedLock.Lock()
+	if t.closed {
+		t.closedLock.Unlock()
+		return errors.Errorf("tar filter is already closed")
+	}
+	t.closed = true
+	t.closedLock.Unlock()
+	err := t.pipeWriter.Close()
+	t.wg.Wait()
+	if err != nil {
+		return errors.Wrapf(err, "error closing filter pipe")
+	}
+	return t.err
+}
+
+// newTarFilterer passes one or more tar archives through to an io.WriteCloser
+// as a single archive, potentially calling filter to modify headers and
+// contents as it goes.
+func newTarFilterer(writeCloser io.WriteCloser, filter func(hdr *tar.Header) (skip, replaceContents bool, replacementContents io.Reader)) io.WriteCloser {
+	pipeReader, pipeWriter := io.Pipe()
+	tarWriter := tar.NewWriter(writeCloser)
+	filterer := &tarFilterer{
+		pipeWriter: pipeWriter,
+	}
+	filterer.wg.Add(1)
+	go func() {
+		filterer.closedLock.Lock()
+		closed := filterer.closed
+		filterer.closedLock.Unlock()
+		for !closed {
+			tarReader := tar.NewReader(pipeReader)
+			hdr, err := tarReader.Next()
+			for err == nil {
+				var skip, replaceContents bool
+				var replacementContents io.Reader
+				if filter != nil {
+					skip, replaceContents, replacementContents = filter(hdr)
+				}
+				if !skip {
+					err = tarWriter.WriteHeader(hdr)
+					if err != nil {
+						err = errors.Wrapf(err, "error filtering tar header for %q", hdr.Name)
+						break
+					}
+					if hdr.Size != 0 {
+						var n int64
+						var copyErr error
+						if replaceContents {
+							n, copyErr = io.CopyN(tarWriter, replacementContents, hdr.Size)
+						} else {
+							n, copyErr = io.Copy(tarWriter, tarReader)
+						}
+						if copyErr != nil {
+							err = errors.Wrapf(copyErr, "error copying content for %q", hdr.Name)
+							break
+						}
+						if n != hdr.Size {
+							err = errors.Errorf("error filtering content for %q: expected %d bytes, got %d bytes", hdr.Name, hdr.Size, n)
+							break
+						}
+					}
+				}
+				hdr, err = tarReader.Next()
+			}
+			if err != io.EOF {
+				filterer.err = errors.Wrapf(err, "error reading tar archive")
+				break
+			}
+			filterer.closedLock.Lock()
+			closed = filterer.closed
+			filterer.closedLock.Unlock()
+		}
+		pipeReader.Close()
+		tarWriter.Close()
+		writeCloser.Close()
+		filterer.wg.Done()
+	}()
+	return filterer
+}
+
+// A tar digester digests an archive, modifying the headers it digests by
+// calling a specified function to potentially modify the header that it's
+// about to write.
+type tarDigester struct {
+	isOpen      bool
+	nested      digester
+	tarFilterer io.WriteCloser
+}
+
+func newTarDigester(contentType string) digester {
+	nested := newSimpleDigester(contentType)
+	digester := &tarDigester{
+		isOpen:      true,
+		nested:      nested,
+		tarFilterer: nested,
+	}
+	return digester
+}
+
+func (t *tarDigester) ContentType() string {
+	return t.nested.ContentType()
+}
+
+func (t *tarDigester) Digest() digest.Digest {
+	return t.nested.Digest()
+}
+
+func (t *tarDigester) Write(p []byte) (int, error) {
+	return t.tarFilterer.Write(p)
+}
+
+func (t *tarDigester) Close() error {
+	if t.isOpen {
+		t.isOpen = false
+		return t.tarFilterer.Close()
+	}
+	return nil
 }
 
 // CompositeDigester can compute a digest over multiple items.
 type CompositeDigester struct {
-	digesters []singleDigester
+	digesters []digester
+	closer    io.Closer
+}
+
+// closeOpenDigester closes an open sub-digester, if we have one.
+func (c *CompositeDigester) closeOpenDigester() {
+	if c.closer != nil {
+		c.closer.Close()
+		c.closer = nil
+	}
 }
 
 // Restart clears all state, so that the composite digester can start over.
 func (c *CompositeDigester) Restart() {
+	c.closeOpenDigester()
 	c.digesters = nil
 }
 
-// Start starts recording the digest for a new item.  The caller should call
-// Hash() immediately after to retrieve the new io.Writer.
-func (c *CompositeDigester) Start(prefix string) {
-	prefix = strings.TrimSuffix(prefix, ":")
-	c.digesters = append(c.digesters, singleDigester{digester: digest.Canonical.Digester(), prefix: prefix})
+// Start starts recording the digest for a new item ("", "file", or "dir").
+// The caller should call Hash() immediately after to retrieve the new
+// io.WriteCloser.
+func (c *CompositeDigester) Start(contentType string) {
+	c.closeOpenDigester()
+	switch contentType {
+	case "":
+		c.digesters = append(c.digesters, newSimpleDigester(""))
+	case "file", "dir":
+		digester := newTarDigester(contentType)
+		c.closer = digester
+		c.digesters = append(c.digesters, digester)
+	default:
+		panic(fmt.Sprintf(`unrecognized content type: expected "", "file", or "dir", got %q`, contentType))
+	}
 }
 
 // Hash returns the hasher for the current item.
-func (c *CompositeDigester) Hash() hash.Hash {
+func (c *CompositeDigester) Hash() io.WriteCloser {
 	num := len(c.digesters)
 	if num == 0 {
 		return nil
 	}
-	return c.digesters[num-1].digester.Hash()
+	return c.digesters[num-1]
 }
 
-// Digest returns the prefix and a composite digest over everything that's been
-// digested.
+// Digest returns the content type and a composite digest over everything
+// that's been digested.
 func (c *CompositeDigester) Digest() (string, digest.Digest) {
+	c.closeOpenDigester()
 	num := len(c.digesters)
 	switch num {
 	case 0:
 		return "", ""
 	case 1:
-		return c.digesters[0].prefix, c.digesters[0].digester.Digest()
+		return c.digesters[0].ContentType(), c.digesters[0].Digest()
 	default:
 		content := ""
 		for i, digester := range c.digesters {
 			if i > 0 {
 				content += ","
 			}
-			prefix := digester.prefix
-			if digester.prefix != "" {
-				digester.prefix += ":"
+			contentType := digester.ContentType()
+			if contentType != "" {
+				contentType += ":"
 			}
-			content += prefix + digester.digester.Digest().Encoded()
+			content += contentType + digester.Digest().Encoded()
 		}
 		return "multi", digest.Canonical.FromString(content)
 	}