github/skopeo
1
0
Fork 0
mirror of https://github.com/containers/skopeo.git synced 2025-09-03 07:35:02 +00:00
Code Issues Projects Releases Wiki Activity

Bump github.com/containers/storage from 1.35.0 to 1.36.0

Browse Source 
Bumps [github.com/containers/storage](https://github.com/containers/storage) from 1.35.0 to 1.36.0.
- [Release notes](https://github.com/containers/storage/releases)
- [Changelog](https://github.com/containers/storage/blob/main/docs/containers-storage-changes.md)
- [Commits](https://github.com/containers/storage/compare/v1.35.0...v1.36.0)

---
updated-dependencies:
- dependency-name: github.com/containers/storage
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
This commit is contained in:
dependabot[bot]
2021-09-13 08:31:20 +00:00
committed by GitHub
parent 47b808275d
commit a837fbe28b
58 changed files with 5256 additions and 4190 deletions
Download Patch File Download Diff File Expand all files Collapse all files

202
vendor/github.com/containerd/stargz-snapshotter/estargz/LICENSE generated vendored Normal file
View File

@@ -0,0 +1,202 @@
Apache License
Version 2.0, January 2004
http://www.apache.org/licenses/
TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
1. Definitions.
"License" shall mean the terms and conditions for use, reproduction,
and distribution as defined by Sections 1 through 9 of this document.
"Licensor" shall mean the copyright owner or entity authorized by
the copyright owner that is granting the License.
"Legal Entity" shall mean the union of the acting entity and all
other entities that control, are controlled by, or are under common
control with that entity. For the purposes of this definition,
"control" means (i) the power, direct or indirect, to cause the
direction or management of such entity, whether by contract or
otherwise, or (ii) ownership of fifty percent (50%) or more of the
outstanding shares, or (iii) beneficial ownership of such entity.
"You" (or "Your") shall mean an individual or Legal Entity
exercising permissions granted by this License.
"Source" form shall mean the preferred form for making modifications,
including but not limited to software source code, documentation
source, and configuration files.
"Object" form shall mean any form resulting from mechanical
transformation or translation of a Source form, including but
not limited to compiled object code, generated documentation,
and conversions to other media types.
"Work" shall mean the work of authorship, whether in Source or
Object form, made available under the License, as indicated by a
copyright notice that is included in or attached to the work
(an example is provided in the Appendix below).
"Derivative Works" shall mean any work, whether in Source or Object
form, that is based on (or derived from) the Work and for which the
editorial revisions, annotations, elaborations, or other modifications
represent, as a whole, an original work of authorship. For the purposes
of this License, Derivative Works shall not include works that remain
separable from, or merely link (or bind by name) to the interfaces of,
the Work and Derivative Works thereof.
"Contribution" shall mean any work of authorship, including
the original version of the Work and any modifications or additions
to that Work or Derivative Works thereof, that is intentionally
submitted to Licensor for inclusion in the Work by the copyright owner
or by an individual or Legal Entity authorized to submit on behalf of
the copyright owner. For the purposes of this definition, "submitted"
means any form of electronic, verbal, or written communication sent
to the Licensor or its representatives, including but not limited to
communication on electronic mailing lists, source code control systems,
and issue tracking systems that are managed by, or on behalf of, the
Licensor for the purpose of discussing and improving the Work, but
excluding communication that is conspicuously marked or otherwise
designated in writing by the copyright owner as "Not a Contribution."
"Contributor" shall mean Licensor and any individual or Legal Entity
on behalf of whom a Contribution has been received by Licensor and
subsequently incorporated within the Work.
2. Grant of Copyright License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
copyright license to reproduce, prepare Derivative Works of,
publicly display, publicly perform, sublicense, and distribute the
Work and such Derivative Works in Source or Object form.
3. Grant of Patent License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
(except as stated in this section) patent license to make, have made,
use, offer to sell, sell, import, and otherwise transfer the Work,
where such license applies only to those patent claims licensable
by such Contributor that are necessarily infringed by their
Contribution(s) alone or by combination of their Contribution(s)
with the Work to which such Contribution(s) was submitted. If You
institute patent litigation against any entity (including a
cross-claim or counterclaim in a lawsuit) alleging that the Work
or a Contribution incorporated within the Work constitutes direct
or contributory patent infringement, then any patent licenses
granted to You under this License for that Work shall terminate
as of the date such litigation is filed.
4. Redistribution. You may reproduce and distribute copies of the
Work or Derivative Works thereof in any medium, with or without
modifications, and in Source or Object form, provided that You
meet the following conditions:
(a) You must give any other recipients of the Work or
Derivative Works a copy of this License; and
(b) You must cause any modified files to carry prominent notices
stating that You changed the files; and
(c) You must retain, in the Source form of any Derivative Works
that You distribute, all copyright, patent, trademark, and
attribution notices from the Source form of the Work,
excluding those notices that do not pertain to any part of
the Derivative Works; and
(d) If the Work includes a "NOTICE" text file as part of its
distribution, then any Derivative Works that You distribute must
include a readable copy of the attribution notices contained
within such NOTICE file, excluding those notices that do not
pertain to any part of the Derivative Works, in at least one
of the following places: within a NOTICE text file distributed
as part of the Derivative Works; within the Source form or
documentation, if provided along with the Derivative Works; or,
within a display generated by the Derivative Works, if and
wherever such third-party notices normally appear. The contents
of the NOTICE file are for informational purposes only and
do not modify the License. You may add Your own attribution
notices within Derivative Works that You distribute, alongside
or as an addendum to the NOTICE text from the Work, provided
that such additional attribution notices cannot be construed
as modifying the License.
You may add Your own copyright statement to Your modifications and
may provide additional or different license terms and conditions
for use, reproduction, or distribution of Your modifications, or
for any such Derivative Works as a whole, provided Your use,
reproduction, and distribution of the Work otherwise complies with
the conditions stated in this License.
5. Submission of Contributions. Unless You explicitly state otherwise,
any Contribution intentionally submitted for inclusion in the Work
by You to the Licensor shall be under the terms and conditions of
this License, without any additional terms or conditions.
Notwithstanding the above, nothing herein shall supersede or modify
the terms of any separate license agreement you may have executed
with Licensor regarding such Contributions.
6. Trademarks. This License does not grant permission to use the trade
names, trademarks, service marks, or product names of the Licensor,
except as required for reasonable and customary use in describing the
origin of the Work and reproducing the content of the NOTICE file.
7. Disclaimer of Warranty. Unless required by applicable law or
agreed to in writing, Licensor provides the Work (and each
Contributor provides its Contributions) on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied, including, without limitation, any warranties or conditions
of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
PARTICULAR PURPOSE. You are solely responsible for determining the
appropriateness of using or redistributing the Work and assume any
risks associated with Your exercise of permissions under this License.
8. Limitation of Liability. In no event and under no legal theory,
whether in tort (including negligence), contract, or otherwise,
unless required by applicable law (such as deliberate and grossly
negligent acts) or agreed to in writing, shall any Contributor be
liable to You for damages, including any direct, indirect, special,
incidental, or consequential damages of any character arising as a
result of this License or out of the use or inability to use the
Work (including but not limited to damages for loss of goodwill,
work stoppage, computer failure or malfunction, or any and all
other commercial damages or losses), even if such Contributor
has been advised of the possibility of such damages.
9. Accepting Warranty or Additional Liability. While redistributing
the Work or Derivative Works thereof, You may choose to offer,
and charge a fee for, acceptance of support, warranty, indemnity,
or other liability obligations and/or rights consistent with this
License. However, in accepting such obligations, You may act only
on Your own behalf and on Your sole responsibility, not on behalf
of any other Contributor, and only if You agree to indemnify,
defend, and hold each Contributor harmless for any liability
incurred by, or claims asserted against, such Contributor by reason
of your accepting any such warranty or additional liability.
END OF TERMS AND CONDITIONS
APPENDIX: How to apply the Apache License to your work.
To apply the Apache License to your work, attach the following
boilerplate notice, with the fields enclosed by brackets "[]"
replaced with your own identifying information. (Don't include
the brackets!) The text should be enclosed in the appropriate
comment syntax for the file format. We also recommend that a
file or class name and description of purpose be included on the
same "printed page" as the copyright notice for easier
identification within third-party archives.
Copyright [yyyy] [name of copyright owner]
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.

628
vendor/github.com/containerd/stargz-snapshotter/estargz/build.go generated vendored Normal file
View File

@@ -0,0 +1,628 @@
/*
Copyright The containerd Authors.
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.
*/
/*
Copyright 2019 The Go Authors. All rights reserved.
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file.
*/
package estargz
import (
"archive/tar"
"bytes"
"compress/gzip"
"fmt"
"io"
"io/ioutil"
"os"
"path"
"runtime"
"strings"
"sync"
"github.com/containerd/stargz-snapshotter/estargz/errorutil"
"github.com/klauspost/compress/zstd"
digest "github.com/opencontainers/go-digest"
"github.com/pkg/errors"
"golang.org/x/sync/errgroup"
)
type options struct {
chunkSize int
compressionLevel int
prioritizedFiles []string
missedPrioritizedFiles *[]string
compression Compression
}
type Option func(o *options) error
// WithChunkSize option specifies the chunk size of eStargz blob to build.
func WithChunkSize(chunkSize int) Option {
return func(o *options) error {
o.chunkSize = chunkSize
return nil
}
}
// WithCompressionLevel option specifies the gzip compression level.
// The default is gzip.BestCompression.
// See also: https://godoc.org/compress/gzip#pkg-constants
func WithCompressionLevel(level int) Option {
return func(o *options) error {
o.compressionLevel = level
return nil
}
}
// WithPrioritizedFiles option specifies the list of prioritized files.
// These files must be complete paths that are absolute or relative to "/"
// For example, all of "foo/bar", "/foo/bar", "./foo/bar" and "../foo/bar"
// are treated as "/foo/bar".
func WithPrioritizedFiles(files []string) Option {
return func(o *options) error {
o.prioritizedFiles = files
return nil
}
}
// WithAllowPrioritizeNotFound makes Build continue the execution even if some
// of prioritized files specified by WithPrioritizedFiles option aren't found
// in the input tar. Instead, this records all missed file names to the passed
// slice.
func WithAllowPrioritizeNotFound(missedFiles *[]string) Option {
return func(o *options) error {
if missedFiles == nil {
return fmt.Errorf("WithAllowPrioritizeNotFound: slice must be passed")
}
o.missedPrioritizedFiles = missedFiles
return nil
}
}
// WithCompression specifies compression algorithm to be used.
// Default is gzip.
func WithCompression(compression Compression) Option {
return func(o *options) error {
o.compression = compression
return nil
}
}
// Blob is an eStargz blob.
type Blob struct {
io.ReadCloser
diffID digest.Digester
tocDigest digest.Digest
}
// DiffID returns the digest of uncompressed blob.
// It is only valid to call DiffID after Close.
func (b *Blob) DiffID() digest.Digest {
return b.diffID.Digest()
}
// TOCDigest returns the digest of uncompressed TOC JSON.
func (b *Blob) TOCDigest() digest.Digest {
return b.tocDigest
}
// Build builds an eStargz blob which is an extended version of stargz, from a blob (gzip, zstd
// or plain tar) passed through the argument. If there are some prioritized files are listed in
// the option, these files are grouped as "prioritized" and can be used for runtime optimization
// (e.g. prefetch). This function builds a blob in parallel, with dividing that blob into several
// (at least the number of runtime.GOMAXPROCS(0)) sub-blobs.
func Build(tarBlob *io.SectionReader, opt ...Option) (_ *Blob, rErr error) {
var opts options
opts.compressionLevel = gzip.BestCompression // BestCompression by default
for _, o := range opt {
if err := o(&opts); err != nil {
return nil, err
}
}
if opts.compression == nil {
opts.compression = newGzipCompressionWithLevel(opts.compressionLevel)
}
layerFiles := newTempFiles()
defer func() {
if rErr != nil {
if err := layerFiles.CleanupAll(); err != nil {
rErr = errors.Wrapf(rErr, "failed to cleanup tmp files: %v", err)
}
}
}()
tarBlob, err := decompressBlob(tarBlob, layerFiles)
if err != nil {
return nil, err
}
entries, err := sortEntries(tarBlob, opts.prioritizedFiles, opts.missedPrioritizedFiles)
if err != nil {
return nil, err
}
tarParts := divideEntries(entries, runtime.GOMAXPROCS(0))
writers := make([]*Writer, len(tarParts))
payloads := make([]*os.File, len(tarParts))
var mu sync.Mutex
var eg errgroup.Group
for i, parts := range tarParts {
i, parts := i, parts
// builds verifiable stargz sub-blobs
eg.Go(func() error {
esgzFile, err := layerFiles.TempFile("", "esgzdata")
if err != nil {
return err
}
sw := NewWriterWithCompressor(esgzFile, opts.compression)
sw.ChunkSize = opts.chunkSize
if err := sw.AppendTar(readerFromEntries(parts...)); err != nil {
return err
}
mu.Lock()
writers[i] = sw
payloads[i] = esgzFile
mu.Unlock()
return nil
})
}
if err := eg.Wait(); err != nil {
rErr = err
return nil, err
}
tocAndFooter, tocDgst, err := closeWithCombine(opts.compressionLevel, writers...)
if err != nil {
rErr = err
return nil, err
}
var rs []io.Reader
for _, p := range payloads {
fs, err := fileSectionReader(p)
if err != nil {
return nil, err
}
rs = append(rs, fs)
}
diffID := digest.Canonical.Digester()
pr, pw := io.Pipe()
go func() {
r, err := opts.compression.Reader(io.TeeReader(io.MultiReader(append(rs, tocAndFooter)...), pw))
if err != nil {
pw.CloseWithError(err)
return
}
defer r.Close()
if _, err := io.Copy(diffID.Hash(), r); err != nil {
pw.CloseWithError(err)
return
}
pw.Close()
}()
return &Blob{
ReadCloser: readCloser{
Reader: pr,
closeFunc: layerFiles.CleanupAll,
},
tocDigest: tocDgst,
diffID: diffID,
}, nil
}
// closeWithCombine takes unclosed Writers and close them. This also returns the
// toc that combined all Writers into.
// Writers doesn't write TOC and footer to the underlying writers so they can be
// combined into a single eStargz and tocAndFooter returned by this function can
// be appended at the tail of that combined blob.
func closeWithCombine(compressionLevel int, ws ...*Writer) (tocAndFooterR io.Reader, tocDgst digest.Digest, err error) {
if len(ws) == 0 {
return nil, "", fmt.Errorf("at least one writer must be passed")
}
for _, w := range ws {
if w.closed {
return nil, "", fmt.Errorf("writer must be unclosed")
}
defer func(w *Writer) { w.closed = true }(w)
if err := w.closeGz(); err != nil {
return nil, "", err
}
if err := w.bw.Flush(); err != nil {
return nil, "", err
}
}
var (
mtoc = new(JTOC)
currentOffset int64
)
mtoc.Version = ws[0].toc.Version
for _, w := range ws {
for _, e := range w.toc.Entries {
// Recalculate Offset of non-empty files/chunks
if (e.Type == "reg" && e.Size > 0) || e.Type == "chunk" {
e.Offset += currentOffset
}
mtoc.Entries = append(mtoc.Entries, e)
}
if w.toc.Version > mtoc.Version {
mtoc.Version = w.toc.Version
}
currentOffset += w.cw.n
}
return tocAndFooter(ws[0].compressor, mtoc, currentOffset)
}
func tocAndFooter(compressor Compressor, toc *JTOC, offset int64) (io.Reader, digest.Digest, error) {
buf := new(bytes.Buffer)
tocDigest, err := compressor.WriteTOCAndFooter(buf, offset, toc, nil)
if err != nil {
return nil, "", err
}
return buf, tocDigest, nil
}
// divideEntries divides passed entries to the parts at least the number specified by the
// argument.
func divideEntries(entries []*entry, minPartsNum int) (set [][]*entry) {
var estimatedSize int64
for _, e := range entries {
estimatedSize += e.header.Size
}
unitSize := estimatedSize / int64(minPartsNum)
var (
nextEnd = unitSize
offset int64
)
set = append(set, []*entry{})
for _, e := range entries {
set[len(set)-1] = append(set[len(set)-1], e)
offset += e.header.Size
if offset > nextEnd {
set = append(set, []*entry{})
nextEnd += unitSize
}
}
return
}
var errNotFound = errors.New("not found")
// sortEntries reads the specified tar blob and returns a list of tar entries.
// If some of prioritized files are specified, the list starts from these
// files with keeping the order specified by the argument.
func sortEntries(in io.ReaderAt, prioritized []string, missedPrioritized *[]string) ([]*entry, error) {
// Import tar file.
intar, err := importTar(in)
if err != nil {
return nil, errors.Wrap(err, "failed to sort")
}
// Sort the tar file respecting to the prioritized files list.
sorted := &tarFile{}
for _, l := range prioritized {
if err := moveRec(l, intar, sorted); err != nil {
if errors.Is(err, errNotFound) && missedPrioritized != nil {
*missedPrioritized = append(*missedPrioritized, l)
continue // allow not found
}
return nil, errors.Wrap(err, "failed to sort tar entries")
}
}
if len(prioritized) == 0 {
sorted.add(&entry{
header: &tar.Header{
Name: NoPrefetchLandmark,
Typeflag: tar.TypeReg,
Size: int64(len([]byte{landmarkContents})),
},
payload: bytes.NewReader([]byte{landmarkContents}),
})
} else {
sorted.add(&entry{
header: &tar.Header{
Name: PrefetchLandmark,
Typeflag: tar.TypeReg,
Size: int64(len([]byte{landmarkContents})),
},
payload: bytes.NewReader([]byte{landmarkContents}),
})
}
// Dump all entry and concatinate them.
return append(sorted.dump(), intar.dump()...), nil
}
// readerFromEntries returns a reader of tar archive that contains entries passed
// through the arguments.
func readerFromEntries(entries ...*entry) io.Reader {
pr, pw := io.Pipe()
go func() {
tw := tar.NewWriter(pw)
defer tw.Close()
for _, entry := range entries {
if err := tw.WriteHeader(entry.header); err != nil {
pw.CloseWithError(fmt.Errorf("Failed to write tar header: %v", err))
return
}
if _, err := io.Copy(tw, entry.payload); err != nil {
pw.CloseWithError(fmt.Errorf("Failed to write tar payload: %v", err))
return
}
}
pw.Close()
}()
return pr
}
func importTar(in io.ReaderAt) (*tarFile, error) {
tf := &tarFile{}
pw, err := newCountReader(in)
if err != nil {
return nil, errors.Wrap(err, "failed to make position watcher")
}
tr := tar.NewReader(pw)
// Walk through all nodes.
for {
// Fetch and parse next header.
h, err := tr.Next()
if err != nil {
if err == io.EOF {
break
} else {
return nil, errors.Wrap(err, "failed to parse tar file")
}
}
switch cleanEntryName(h.Name) {
case PrefetchLandmark, NoPrefetchLandmark:
// Ignore existing landmark
continue
}
// Add entry. If it already exists, replace it.
if _, ok := tf.get(h.Name); ok {
tf.remove(h.Name)
}
tf.add(&entry{
header: h,
payload: io.NewSectionReader(in, pw.currentPos(), h.Size),
})
}
return tf, nil
}
func moveRec(name string, in *tarFile, out *tarFile) error {
name = cleanEntryName(name)
if name == "" { // root directory. stop recursion.
if e, ok := in.get(name); ok {
// entry of the root directory exists. we should move it as well.
// this case will occur if tar entries are prefixed with "./", "/", etc.
out.add(e)
in.remove(name)
}
return nil
}
_, okIn := in.get(name)
_, okOut := out.get(name)
if !okIn && !okOut {
return errors.Wrapf(errNotFound, "file: %q", name)
}
parent, _ := path.Split(strings.TrimSuffix(name, "/"))
if err := moveRec(parent, in, out); err != nil {
return err
}
if e, ok := in.get(name); ok && e.header.Typeflag == tar.TypeLink {
if err := moveRec(e.header.Linkname, in, out); err != nil {
return err
}
}
if e, ok := in.get(name); ok {
out.add(e)
in.remove(name)
}
return nil
}
type entry struct {
header *tar.Header
payload io.ReadSeeker
}
type tarFile struct {
index map[string]*entry
stream []*entry
}
func (f *tarFile) add(e *entry) {
if f.index == nil {
f.index = make(map[string]*entry)
}
f.index[cleanEntryName(e.header.Name)] = e
f.stream = append(f.stream, e)
}
func (f *tarFile) remove(name string) {
name = cleanEntryName(name)
if f.index != nil {
delete(f.index, name)
}
var filtered []*entry
for _, e := range f.stream {
if cleanEntryName(e.header.Name) == name {
continue
}
filtered = append(filtered, e)
}
f.stream = filtered
}
func (f *tarFile) get(name string) (e *entry, ok bool) {
if f.index == nil {
return nil, false
}
e, ok = f.index[cleanEntryName(name)]
return
}
func (f *tarFile) dump() []*entry {
return f.stream
}
type readCloser struct {
io.Reader
closeFunc func() error
}
func (rc readCloser) Close() error {
return rc.closeFunc()
}
func fileSectionReader(file *os.File) (*io.SectionReader, error) {
info, err := file.Stat()
if err != nil {
return nil, err
}
return io.NewSectionReader(file, 0, info.Size()), nil
}
func newTempFiles() *tempFiles {
return &tempFiles{}
}
type tempFiles struct {
files []*os.File
filesMu sync.Mutex
}
func (tf *tempFiles) TempFile(dir, pattern string) (*os.File, error) {
f, err := ioutil.TempFile(dir, pattern)
if err != nil {
return nil, err
}
tf.filesMu.Lock()
tf.files = append(tf.files, f)
tf.filesMu.Unlock()
return f, nil
}
func (tf *tempFiles) CleanupAll() error {
tf.filesMu.Lock()
defer tf.filesMu.Unlock()
var allErr []error
for _, f := range tf.files {
if err := f.Close(); err != nil {
allErr = append(allErr, err)
}
if err := os.Remove(f.Name()); err != nil {
allErr = append(allErr, err)
}
}
tf.files = nil
return errorutil.Aggregate(allErr)
}
func newCountReader(r io.ReaderAt) (*countReader, error) {
pos := int64(0)
return &countReader{r: r, cPos: &pos}, nil
}
type countReader struct {
r io.ReaderAt
cPos *int64
mu sync.Mutex
}
func (cr *countReader) Read(p []byte) (int, error) {
cr.mu.Lock()
defer cr.mu.Unlock()
n, err := cr.r.ReadAt(p, *cr.cPos)
if err == nil {
*cr.cPos += int64(n)
}
return n, err
}
func (cr *countReader) Seek(offset int64, whence int) (int64, error) {
cr.mu.Lock()
defer cr.mu.Unlock()
switch whence {
default:
return 0, fmt.Errorf("Unknown whence: %v", whence)
case io.SeekStart:
case io.SeekCurrent:
offset += *cr.cPos
case io.SeekEnd:
return 0, fmt.Errorf("Unsupported whence: %v", whence)
}
if offset < 0 {
return 0, fmt.Errorf("invalid offset")
}
*cr.cPos = offset
return offset, nil
}
func (cr *countReader) currentPos() int64 {
cr.mu.Lock()
defer cr.mu.Unlock()
return *cr.cPos
}
func decompressBlob(org *io.SectionReader, tmp *tempFiles) (*io.SectionReader, error) {
if org.Size() < 4 {
return org, nil
}
src := make([]byte, 4)
if _, err := org.Read(src); err != nil && err != io.EOF {
return nil, err
}
var dR io.Reader
if bytes.Equal([]byte{0x1F, 0x8B, 0x08}, src[:3]) {
// gzip
dgR, err := gzip.NewReader(io.NewSectionReader(org, 0, org.Size()))
if err != nil {
return nil, err
}
defer dgR.Close()
dR = io.Reader(dgR)
} else if bytes.Equal([]byte{0x28, 0xb5, 0x2f, 0xfd}, src[:4]) {
// zstd
dzR, err := zstd.NewReader(io.NewSectionReader(org, 0, org.Size()))
if err != nil {
return nil, err
}
defer dzR.Close()
dR = io.Reader(dzR)
} else {
// uncompressed
return io.NewSectionReader(org, 0, org.Size()), nil
}
b, err := tmp.TempFile("", "uncompresseddata")
if err != nil {
return nil, err
}
if _, err := io.Copy(b, dR); err != nil {
return nil, err
}
return fileSectionReader(b)
}

40
vendor/github.com/containerd/stargz-snapshotter/estargz/errorutil/errors.go generated vendored Normal file
View File

@@ -0,0 +1,40 @@
/*
Copyright The containerd Authors.
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 errorutil
import (
"errors"
"fmt"
"strings"
)
// Aggregate combines a list of errors into a single new error.
func Aggregate(errs []error) error {
switch len(errs) {
case 0:
return nil
case 1:
return errs[0]
default:
points := make([]string, len(errs)+1)
points[0] = fmt.Sprintf("%d error(s) occurred:", len(errs))
for i, err := range errs {
points[i+1] = fmt.Sprintf("* %s", err)
}
return errors.New(strings.Join(points, "\n\t"))
}
}

933
vendor/github.com/containerd/stargz-snapshotter/estargz/estargz.go generated vendored Normal file
View File

@@ -0,0 +1,933 @@
/*
Copyright The containerd Authors.
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.
*/
/*
Copyright 2019 The Go Authors. All rights reserved.
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file.
*/
package estargz
import (
"archive/tar"
"bufio"
"bytes"
"compress/gzip"
"crypto/sha256"
"fmt"
"hash"
"io"
"io/ioutil"
"os"
"path"
"sort"
"strings"
"sync"
"time"
"github.com/containerd/stargz-snapshotter/estargz/errorutil"
digest "github.com/opencontainers/go-digest"
"github.com/pkg/errors"
)
// A Reader permits random access reads from a stargz file.
type Reader struct {
sr *io.SectionReader
toc *JTOC
tocDigest digest.Digest
// m stores all non-chunk entries, keyed by name.
m map[string]*TOCEntry
// chunks stores all TOCEntry values for regular files that
// are split up. For a file with a single chunk, it's only
// stored in m.
chunks map[string][]*TOCEntry
decompressor Decompressor
}
type openOpts struct {
tocOffset int64
decompressors []Decompressor
telemetry *Telemetry
}
// OpenOption is an option used during opening the layer
type OpenOption func(o *openOpts) error
// WithTOCOffset option specifies the offset of TOC
func WithTOCOffset(tocOffset int64) OpenOption {
return func(o *openOpts) error {
o.tocOffset = tocOffset
return nil
}
}
// WithDecompressors option specifies decompressors to use.
// Default is gzip-based decompressor.
func WithDecompressors(decompressors ...Decompressor) OpenOption {
return func(o *openOpts) error {
o.decompressors = decompressors
return nil
}
}
// WithTelemetry option specifies the telemetry hooks
func WithTelemetry(telemetry *Telemetry) OpenOption {
return func(o *openOpts) error {
o.telemetry = telemetry
return nil
}
}
// A func which takes start time and records the diff
type MeasureLatencyHook func(time.Time)
// A struct which defines telemetry hooks. By implementing these hooks you should be able to record
// the latency metrics of the respective steps of estargz open operation. To be used with estargz.OpenWithTelemetry(...)
type Telemetry struct {
GetFooterLatency MeasureLatencyHook // measure time to get stargz footer (in milliseconds)
GetTocLatency MeasureLatencyHook // measure time to GET TOC JSON (in milliseconds)
DeserializeTocLatency MeasureLatencyHook // measure time to deserialize TOC JSON (in milliseconds)
}
// Open opens a stargz file for reading.
// The behaviour is configurable using options.
//
// Note that each entry name is normalized as the path that is relative to root.
func Open(sr *io.SectionReader, opt ...OpenOption) (*Reader, error) {
var opts openOpts
for _, o := range opt {
if err := o(&opts); err != nil {
return nil, err
}
}
gzipCompressors := []Decompressor{new(GzipDecompressor), new(legacyGzipDecompressor)}
decompressors := append(gzipCompressors, opts.decompressors...)
// Determine the size to fetch. Try to fetch as many bytes as possible.
fetchSize := maxFooterSize(sr.Size(), decompressors...)
if maybeTocOffset := opts.tocOffset; maybeTocOffset > fetchSize {
if maybeTocOffset > sr.Size() {
return nil, fmt.Errorf("blob size %d is smaller than the toc offset", sr.Size())
}
fetchSize = sr.Size() - maybeTocOffset
}
start := time.Now() // before getting layer footer
footer := make([]byte, fetchSize)
if _, err := sr.ReadAt(footer, sr.Size()-fetchSize); err != nil {
return nil, fmt.Errorf("error reading footer: %v", err)
}
if opts.telemetry != nil && opts.telemetry.GetFooterLatency != nil {
opts.telemetry.GetFooterLatency(start)
}
var allErr []error
var found bool
var r *Reader
for _, d := range decompressors {
fSize := d.FooterSize()
fOffset := positive(int64(len(footer)) - fSize)
maybeTocBytes := footer[:fOffset]
tocOffset, tocSize, err := d.ParseFooter(footer[fOffset:])
if err != nil {
allErr = append(allErr, err)
continue
}
if tocSize <= 0 {
tocSize = sr.Size() - tocOffset - fSize
}
if tocSize < int64(len(maybeTocBytes)) {
maybeTocBytes = maybeTocBytes[:tocSize]
}
r, err = parseTOC(d, sr, tocOffset, tocSize, maybeTocBytes, opts)
if err == nil {
found = true
break
}
allErr = append(allErr, err)
}
if !found {
return nil, errorutil.Aggregate(allErr)
}
if err := r.initFields(); err != nil {
return nil, fmt.Errorf("failed to initialize fields of entries: %v", err)
}
return r, nil
}
// OpenFooter extracts and parses footer from the given blob.
// only supports gzip-based eStargz.
func OpenFooter(sr *io.SectionReader) (tocOffset int64, footerSize int64, rErr error) {
if sr.Size() < FooterSize && sr.Size() < legacyFooterSize {
return 0, 0, fmt.Errorf("blob size %d is smaller than the footer size", sr.Size())
}
var footer [FooterSize]byte
if _, err := sr.ReadAt(footer[:], sr.Size()-FooterSize); err != nil {
return 0, 0, fmt.Errorf("error reading footer: %v", err)
}
var allErr []error
for _, d := range []Decompressor{new(GzipDecompressor), new(legacyGzipDecompressor)} {
fSize := d.FooterSize()
fOffset := positive(int64(len(footer)) - fSize)
tocOffset, _, err := d.ParseFooter(footer[fOffset:])
if err == nil {
return tocOffset, fSize, err
}
allErr = append(allErr, err)
}
return 0, 0, errorutil.Aggregate(allErr)
}
// initFields populates the Reader from r.toc after decoding it from
// JSON.
//
// Unexported fields are populated and TOCEntry fields that were
// implicit in the JSON are populated.
func (r *Reader) initFields() error {
r.m = make(map[string]*TOCEntry, len(r.toc.Entries))
r.chunks = make(map[string][]*TOCEntry)
var lastPath string
uname := map[int]string{}
gname := map[int]string{}
var lastRegEnt *TOCEntry
for _, ent := range r.toc.Entries {
ent.Name = cleanEntryName(ent.Name)
if ent.Type == "reg" {
lastRegEnt = ent
}
if ent.Type == "chunk" {
ent.Name = lastPath
r.chunks[ent.Name] = append(r.chunks[ent.Name], ent)
if ent.ChunkSize == 0 && lastRegEnt != nil {
ent.ChunkSize = lastRegEnt.Size - ent.ChunkOffset
}
} else {
lastPath = ent.Name
if ent.Uname != "" {
uname[ent.UID] = ent.Uname
} else {
ent.Uname = uname[ent.UID]
}
if ent.Gname != "" {
gname[ent.GID] = ent.Gname
} else {
ent.Gname = uname[ent.GID]
}
ent.modTime, _ = time.Parse(time.RFC3339, ent.ModTime3339)
if ent.Type == "dir" {
ent.NumLink++ // Parent dir links to this directory
}
r.m[ent.Name] = ent
}
if ent.Type == "reg" && ent.ChunkSize > 0 && ent.ChunkSize < ent.Size {
r.chunks[ent.Name] = make([]*TOCEntry, 0, ent.Size/ent.ChunkSize+1)
r.chunks[ent.Name] = append(r.chunks[ent.Name], ent)
}
if ent.ChunkSize == 0 && ent.Size != 0 {
ent.ChunkSize = ent.Size
}
}
// Populate children, add implicit directories:
for _, ent := range r.toc.Entries {
if ent.Type == "chunk" {
continue
}
// add "foo/":
// add "foo" child to "" (creating "" if necessary)
//
// add "foo/bar/":
// add "bar" child to "foo" (creating "foo" if necessary)
//
// add "foo/bar.txt":
// add "bar.txt" child to "foo" (creating "foo" if necessary)
//
// add "a/b/c/d/e/f.txt":
// create "a/b/c/d/e" node
// add "f.txt" child to "e"
name := ent.Name
pdirName := parentDir(name)
if name == pdirName {
// This entry and its parent are the same.
// Ignore this for avoiding infinite loop of the reference.
// The example case where this can occur is when tar contains the root
// directory itself (e.g. "./", "/").
continue
}
pdir := r.getOrCreateDir(pdirName)
ent.NumLink++ // at least one name(ent.Name) references this entry.
if ent.Type == "hardlink" {
if org, ok := r.m[cleanEntryName(ent.LinkName)]; ok {
org.NumLink++ // original entry is referenced by this ent.Name.
ent = org
} else {
return fmt.Errorf("%q is a hardlink but the linkname %q isn't found", ent.Name, ent.LinkName)
}
}
pdir.addChild(path.Base(name), ent)
}
lastOffset := r.sr.Size()
for i := len(r.toc.Entries) - 1; i >= 0; i-- {
e := r.toc.Entries[i]
if e.isDataType() {
e.nextOffset = lastOffset
}
if e.Offset != 0 {
lastOffset = e.Offset
}
}
return nil
}
func parentDir(p string) string {
dir, _ := path.Split(p)
return strings.TrimSuffix(dir, "/")
}
func (r *Reader) getOrCreateDir(d string) *TOCEntry {
e, ok := r.m[d]
if !ok {
e = &TOCEntry{
Name: d,
Type: "dir",
Mode: 0755,
NumLink: 2, // The directory itself(.) and the parent link to this directory.
}
r.m[d] = e
if d != "" {
pdir := r.getOrCreateDir(parentDir(d))
pdir.addChild(path.Base(d), e)
}
}
return e
}
// VerifyTOC checks that the TOC JSON in the passed blob matches the
// passed digests and that the TOC JSON contains digests for all chunks
// contained in the blob. If the verification succceeds, this function
// returns TOCEntryVerifier which holds all chunk digests in the stargz blob.
func (r *Reader) VerifyTOC(tocDigest digest.Digest) (TOCEntryVerifier, error) {
// Verify the digest of TOC JSON
if r.tocDigest != tocDigest {
return nil, fmt.Errorf("invalid TOC JSON %q; want %q", r.tocDigest, tocDigest)
}
chunkDigestMap := make(map[int64]digest.Digest) // map from chunk offset to the chunk digest
regDigestMap := make(map[int64]digest.Digest) // map from chunk offset to the reg file digest
var chunkDigestMapIncomplete bool
var regDigestMapIncomplete bool
var containsChunk bool
for _, e := range r.toc.Entries {
if e.Type != "reg" && e.Type != "chunk" {
continue
}
// offset must be unique in stargz blob
_, dOK := chunkDigestMap[e.Offset]
_, rOK := regDigestMap[e.Offset]
if dOK || rOK {
return nil, fmt.Errorf("offset %d found twice", e.Offset)
}
if e.Type == "reg" {
if e.Size == 0 {
continue // ignores empty file
}
// record the digest of regular file payload
if e.Digest != "" {
d, err := digest.Parse(e.Digest)
if err != nil {
return nil, errors.Wrapf(err,
"failed to parse regular file digest %q", e.Digest)
}
regDigestMap[e.Offset] = d
} else {
regDigestMapIncomplete = true
}
} else {
containsChunk = true // this layer contains "chunk" entries.
}
// "reg" also can contain ChunkDigest (e.g. when "reg" is the first entry of
// chunked file)
if e.ChunkDigest != "" {
d, err := digest.Parse(e.ChunkDigest)
if err != nil {
return nil, errors.Wrapf(err,
"failed to parse chunk digest %q", e.ChunkDigest)
}
chunkDigestMap[e.Offset] = d
} else {
chunkDigestMapIncomplete = true
}
}
if chunkDigestMapIncomplete {
// Though some chunk digests are not found, if this layer doesn't contain
// "chunk"s and all digest of "reg" files are recorded, we can use them instead.
if !containsChunk && !regDigestMapIncomplete {
return &verifier{digestMap: regDigestMap}, nil
}
return nil, fmt.Errorf("some ChunkDigest not found in TOC JSON")
}
return &verifier{digestMap: chunkDigestMap}, nil
}
// verifier is an implementation of TOCEntryVerifier which holds verifiers keyed by
// offset of the chunk.
type verifier struct {
digestMap map[int64]digest.Digest
digestMapMu sync.Mutex
}
// Verifier returns a content verifier specified by TOCEntry.
func (v *verifier) Verifier(ce *TOCEntry) (digest.Verifier, error) {
v.digestMapMu.Lock()
defer v.digestMapMu.Unlock()
d, ok := v.digestMap[ce.Offset]
if !ok {
return nil, fmt.Errorf("verifier for offset=%d,size=%d hasn't been registered",
ce.Offset, ce.ChunkSize)
}
return d.Verifier(), nil
}
// ChunkEntryForOffset returns the TOCEntry containing the byte of the
// named file at the given offset within the file.
// Name must be absolute path or one that is relative to root.
func (r *Reader) ChunkEntryForOffset(name string, offset int64) (e *TOCEntry, ok bool) {
name = cleanEntryName(name)
e, ok = r.Lookup(name)
if !ok || !e.isDataType() {
return nil, false
}
ents := r.chunks[name]
if len(ents) < 2 {
if offset >= e.ChunkSize {
return nil, false
}
return e, true
}
i := sort.Search(len(ents), func(i int) bool {
e := ents[i]
return e.ChunkOffset >= offset || (offset > e.ChunkOffset && offset < e.ChunkOffset+e.ChunkSize)
})
if i == len(ents) {
return nil, false
}
return ents[i], true
}
// Lookup returns the Table of Contents entry for the given path.
//
// To get the root directory, use the empty string.
// Path must be absolute path or one that is relative to root.
func (r *Reader) Lookup(path string) (e *TOCEntry, ok bool) {
path = cleanEntryName(path)
if r == nil {
return
}
e, ok = r.m[path]
if ok && e.Type == "hardlink" {
e, ok = r.m[e.LinkName]
}
return
}
// OpenFile returns the reader of the specified file payload.
//
// Name must be absolute path or one that is relative to root.
func (r *Reader) OpenFile(name string) (*io.SectionReader, error) {
name = cleanEntryName(name)
ent, ok := r.Lookup(name)
if !ok {
// TODO: come up with some error plan. This is lazy:
return nil, &os.PathError{
Path: name,
Op: "OpenFile",
Err: os.ErrNotExist,
}
}
if ent.Type != "reg" {
return nil, &os.PathError{
Path: name,
Op: "OpenFile",
Err: errors.New("not a regular file"),
}
}
fr := &fileReader{
r: r,
size: ent.Size,
ents: r.getChunks(ent),
}
return io.NewSectionReader(fr, 0, fr.size), nil
}
func (r *Reader) getChunks(ent *TOCEntry) []*TOCEntry {
if ents, ok := r.chunks[ent.Name]; ok {
return ents
}
return []*TOCEntry{ent}
}
type fileReader struct {
r *Reader
size int64
ents []*TOCEntry // 1 or more reg/chunk entries
}
func (fr *fileReader) ReadAt(p []byte, off int64) (n int, err error) {
if off >= fr.size {
return 0, io.EOF
}
if off < 0 {
return 0, errors.New("invalid offset")
}
var i int
if len(fr.ents) > 1 {
i = sort.Search(len(fr.ents), func(i int) bool {
return fr.ents[i].ChunkOffset >= off
})
if i == len(fr.ents) {
i = len(fr.ents) - 1
}
}
ent := fr.ents[i]
if ent.ChunkOffset > off {
if i == 0 {
return 0, errors.New("internal error; first chunk offset is non-zero")
}
ent = fr.ents[i-1]
}
// If ent is a chunk of a large file, adjust the ReadAt
// offset by the chunk's offset.
off -= ent.ChunkOffset
finalEnt := fr.ents[len(fr.ents)-1]
compressedOff := ent.Offset
// compressedBytesRemain is the number of compressed bytes in this
// file remaining, over 1+ chunks.
compressedBytesRemain := finalEnt.NextOffset() - compressedOff
sr := io.NewSectionReader(fr.r.sr, compressedOff, compressedBytesRemain)
const maxRead = 2 << 20
var bufSize = maxRead
if compressedBytesRemain < maxRead {
bufSize = int(compressedBytesRemain)
}
br := bufio.NewReaderSize(sr, bufSize)
if _, err := br.Peek(bufSize); err != nil {
return 0, fmt.Errorf("fileReader.ReadAt.peek: %v", err)
}
dr, err := fr.r.decompressor.Reader(br)
if err != nil {
return 0, fmt.Errorf("fileReader.ReadAt.decompressor.Reader: %v", err)
}
defer dr.Close()
if n, err := io.CopyN(ioutil.Discard, dr, off); n != off || err != nil {
return 0, fmt.Errorf("discard of %d bytes = %v, %v", off, n, err)
}
return io.ReadFull(dr, p)
}
// A Writer writes stargz files.
//
// Use NewWriter to create a new Writer.
type Writer struct {
bw *bufio.Writer
cw *countWriter
toc *JTOC
diffHash hash.Hash // SHA-256 of uncompressed tar
closed bool
gz io.WriteCloser
lastUsername map[int]string
lastGroupname map[int]string
compressor Compressor
// ChunkSize optionally controls the maximum number of bytes
// of data of a regular file that can be written in one gzip
// stream before a new gzip stream is started.
// Zero means to use a default, currently 4 MiB.
ChunkSize int
}
// currentCompressionWriter writes to the current w.gz field, which can
// change throughout writing a tar entry.
//
// Additionally, it updates w's SHA-256 of the uncompressed bytes
// of the tar file.
type currentCompressionWriter struct{ w *Writer }
func (ccw currentCompressionWriter) Write(p []byte) (int, error) {
ccw.w.diffHash.Write(p)
return ccw.w.gz.Write(p)
}
func (w *Writer) chunkSize() int {
if w.ChunkSize <= 0 {
return 4 << 20
}
return w.ChunkSize
}
// NewWriter returns a new stargz writer (gzip-based) writing to w.
//
// The writer must be closed to write its trailing table of contents.
func NewWriter(w io.Writer) *Writer {
return NewWriterLevel(w, gzip.BestCompression)
}
// NewWriterLevel returns a new stargz writer (gzip-based) writing to w.
// The compression level is configurable.
//
// The writer must be closed to write its trailing table of contents.
func NewWriterLevel(w io.Writer, compressionLevel int) *Writer {
return NewWriterWithCompressor(w, NewGzipCompressorWithLevel(compressionLevel))
}
// NewWriterLevel returns a new stargz writer writing to w.
// The compression method is configurable.
//
// The writer must be closed to write its trailing table of contents.
func NewWriterWithCompressor(w io.Writer, c Compressor) *Writer {
bw := bufio.NewWriter(w)
cw := &countWriter{w: bw}
return &Writer{
bw: bw,
cw: cw,
toc: &JTOC{Version: 1},
diffHash: sha256.New(),
compressor: c,
}
}
// Close writes the stargz's table of contents and flushes all the
// buffers, returning any error.
func (w *Writer) Close() (digest.Digest, error) {
if w.closed {
return "", nil
}
defer func() { w.closed = true }()
if err := w.closeGz(); err != nil {
return "", err
}
// Write the TOC index and footer.
tocDigest, err := w.compressor.WriteTOCAndFooter(w.cw, w.cw.n, w.toc, w.diffHash)
if err != nil {
return "", err
}
if err := w.bw.Flush(); err != nil {
return "", err
}
return tocDigest, nil
}
func (w *Writer) closeGz() error {
if w.closed {
return errors.New("write on closed Writer")
}
if w.gz != nil {
if err := w.gz.Close(); err != nil {
return err
}
w.gz = nil
}
return nil
}
// nameIfChanged returns name, unless it was the already the value of (*mp)[id],
// in which case it returns the empty string.
func (w *Writer) nameIfChanged(mp *map[int]string, id int, name string) string {
if name == "" {
return ""
}
if *mp == nil {
*mp = make(map[int]string)
}
if (*mp)[id] == name {
return ""
}
(*mp)[id] = name
return name
}
func (w *Writer) condOpenGz() (err error) {
if w.gz == nil {
w.gz, err = w.compressor.Writer(w.cw)
}
return
}
// AppendTar reads the tar or tar.gz file from r and appends
// each of its contents to w.
//
// The input r can optionally be gzip compressed but the output will
// always be gzip compressed.
func (w *Writer) AppendTar(r io.Reader) error {
br := bufio.NewReader(r)
var tr *tar.Reader
if isGzip(br) {
// NewReader can't fail if isGzip returned true.
zr, _ := gzip.NewReader(br)
tr = tar.NewReader(zr)
} else {
tr = tar.NewReader(br)
}
for {
h, err := tr.Next()
if err == io.EOF {
break
}
if err != nil {
return fmt.Errorf("error reading from source tar: tar.Reader.Next: %v", err)
}
if h.Name == TOCTarName {
// It is possible for a layer to be "stargzified" twice during the
// distribution lifecycle. So we reserve "TOCTarName" here to avoid
// duplicated entries in the resulting layer.
continue
}
xattrs := make(map[string][]byte)
const xattrPAXRecordsPrefix = "SCHILY.xattr."
if h.PAXRecords != nil {
for k, v := range h.PAXRecords {
if strings.HasPrefix(k, xattrPAXRecordsPrefix) {
xattrs[k[len(xattrPAXRecordsPrefix):]] = []byte(v)
}
}
}
ent := &TOCEntry{
Name: h.Name,
Mode: h.Mode,
UID: h.Uid,
GID: h.Gid,
Uname: w.nameIfChanged(&w.lastUsername, h.Uid, h.Uname),
Gname: w.nameIfChanged(&w.lastGroupname, h.Gid, h.Gname),
ModTime3339: formatModtime(h.ModTime),
Xattrs: xattrs,
}
if err := w.condOpenGz(); err != nil {
return err
}
tw := tar.NewWriter(currentCompressionWriter{w})
if err := tw.WriteHeader(h); err != nil {
return err
}
switch h.Typeflag {
case tar.TypeLink:
ent.Type = "hardlink"
ent.LinkName = h.Linkname
case tar.TypeSymlink:
ent.Type = "symlink"
ent.LinkName = h.Linkname
case tar.TypeDir:
ent.Type = "dir"
case tar.TypeReg:
ent.Type = "reg"
ent.Size = h.Size
case tar.TypeChar:
ent.Type = "char"
ent.DevMajor = int(h.Devmajor)
ent.DevMinor = int(h.Devminor)
case tar.TypeBlock:
ent.Type = "block"
ent.DevMajor = int(h.Devmajor)
ent.DevMinor = int(h.Devminor)
case tar.TypeFifo:
ent.Type = "fifo"
default:
return fmt.Errorf("unsupported input tar entry %q", h.Typeflag)
}
// We need to keep a reference to the TOC entry for regular files, so that we
// can fill the digest later.
var regFileEntry *TOCEntry
var payloadDigest digest.Digester
if h.Typeflag == tar.TypeReg {
regFileEntry = ent
payloadDigest = digest.Canonical.Digester()
}
if h.Typeflag == tar.TypeReg && ent.Size > 0 {
var written int64
totalSize := ent.Size // save it before we destroy ent
tee := io.TeeReader(tr, payloadDigest.Hash())
for written < totalSize {
if err := w.closeGz(); err != nil {
return err
}
chunkSize := int64(w.chunkSize())
remain := totalSize - written
if remain < chunkSize {
chunkSize = remain
} else {
ent.ChunkSize = chunkSize
}
ent.Offset = w.cw.n
ent.ChunkOffset = written
chunkDigest := digest.Canonical.Digester()
if err := w.condOpenGz(); err != nil {
return err
}
teeChunk := io.TeeReader(tee, chunkDigest.Hash())
if _, err := io.CopyN(tw, teeChunk, chunkSize); err != nil {
return fmt.Errorf("error copying %q: %v", h.Name, err)
}
ent.ChunkDigest = chunkDigest.Digest().String()
w.toc.Entries = append(w.toc.Entries, ent)
written += chunkSize
ent = &TOCEntry{
Name: h.Name,
Type: "chunk",
}
}
} else {
w.toc.Entries = append(w.toc.Entries, ent)
}
if payloadDigest != nil {
regFileEntry.Digest = payloadDigest.Digest().String()
}
if err := tw.Flush(); err != nil {
return err
}
}
return nil
}
// DiffID returns the SHA-256 of the uncompressed tar bytes.
// It is only valid to call DiffID after Close.
func (w *Writer) DiffID() string {
return fmt.Sprintf("sha256:%x", w.diffHash.Sum(nil))
}
func maxFooterSize(blobSize int64, decompressors ...Decompressor) (res int64) {
for _, d := range decompressors {
if s := d.FooterSize(); res < s && s <= blobSize {
res = s
}
}
return
}
func parseTOC(d Decompressor, sr *io.SectionReader, tocOff, tocSize int64, tocBytes []byte, opts openOpts) (*Reader, error) {
if len(tocBytes) > 0 {
start := time.Now()
toc, tocDgst, err := d.ParseTOC(bytes.NewReader(tocBytes))
if err == nil {
if opts.telemetry != nil && opts.telemetry.DeserializeTocLatency != nil {
opts.telemetry.DeserializeTocLatency(start)
}
return &Reader{
sr: sr,
toc: toc,
tocDigest: tocDgst,
decompressor: d,
}, nil
}
}
start := time.Now()
tocBytes = make([]byte, tocSize)
if _, err := sr.ReadAt(tocBytes, tocOff); err != nil {
return nil, fmt.Errorf("error reading %d byte TOC targz: %v", len(tocBytes), err)
}
if opts.telemetry != nil && opts.telemetry.GetTocLatency != nil {
opts.telemetry.GetTocLatency(start)
}
start = time.Now()
toc, tocDgst, err := d.ParseTOC(bytes.NewReader(tocBytes))
if err != nil {
return nil, err
}
if opts.telemetry != nil && opts.telemetry.DeserializeTocLatency != nil {
opts.telemetry.DeserializeTocLatency(start)
}
return &Reader{
sr: sr,
toc: toc,
tocDigest: tocDgst,
decompressor: d,
}, nil
}
func formatModtime(t time.Time) string {
if t.IsZero() || t.Unix() == 0 {
return ""
}
return t.UTC().Round(time.Second).Format(time.RFC3339)
}
func cleanEntryName(name string) string {
// Use path.Clean to consistently deal with path separators across platforms.
return strings.TrimPrefix(path.Clean("/"+name), "/")
}
// countWriter counts how many bytes have been written to its wrapped
// io.Writer.
type countWriter struct {
w io.Writer
n int64
}
func (cw *countWriter) Write(p []byte) (n int, err error) {
n, err = cw.w.Write(p)
cw.n += int64(n)
return
}
// isGzip reports whether br is positioned right before an upcoming gzip stream.
// It does not consume any bytes from br.
func isGzip(br *bufio.Reader) bool {
const (
gzipID1 = 0x1f
gzipID2 = 0x8b
gzipDeflate = 8
)
peek, _ := br.Peek(3)
return len(peek) >= 3 && peek[0] == gzipID1 && peek[1] == gzipID2 && peek[2] == gzipDeflate
}
func positive(n int64) int64 {
if n < 0 {
return 0
}
return n
}

10
vendor/github.com/containerd/stargz-snapshotter/estargz/go.mod generated vendored Normal file
View File

@@ -0,0 +1,10 @@
module github.com/containerd/stargz-snapshotter/estargz
go 1.16
require (
github.com/klauspost/compress v1.13.5
github.com/opencontainers/go-digest v1.0.0
github.com/pkg/errors v0.9.1
golang.org/x/sync v0.0.0-20201207232520-09787c993a3a
)

8
vendor/github.com/containerd/stargz-snapshotter/estargz/go.sum generated vendored Normal file
View File

@@ -0,0 +1,8 @@
github.com/klauspost/compress v1.13.5 h1:9O69jUPDcsT9fEm74W92rZL9FQY7rCdaXVneq+yyzl4=
github.com/klauspost/compress v1.13.5/go.mod h1:/3/Vjq9QcHkK5uEr5lBEmyoZ1iFhe47etQ6QUkpK6sk=
github.com/opencontainers/go-digest v1.0.0 h1:apOUWs51W5PlhuyGyz9FCeeBIOUDA/6nW8Oi/yOhh5U=
github.com/opencontainers/go-digest v1.0.0/go.mod h1:0JzlMkj0TRzQZfJkVvzbP0HBR3IKzErnv2BNG4W4MAM=
github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
golang.org/x/sync v0.0.0-20201207232520-09787c993a3a h1:DcqTD9SDLc+1P/r1EmRBwnVsrOwW+kk2vWf9n+1sGhs=
golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=

216
vendor/github.com/containerd/stargz-snapshotter/estargz/gzip.go generated vendored Normal file
View File

@@ -0,0 +1,216 @@
/*
Copyright The containerd Authors.
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.
*/
/*
Copyright 2019 The Go Authors. All rights reserved.
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file.
*/
package estargz
import (
"archive/tar"
"bytes"
"compress/gzip"
"encoding/binary"
"encoding/json"
"fmt"
"hash"
"io"
"strconv"
digest "github.com/opencontainers/go-digest"
"github.com/pkg/errors"
)
type gzipCompression struct {
*gzipCompressor
*GzipDecompressor
}
func newGzipCompressionWithLevel(level int) Compression {
return &gzipCompression{
&gzipCompressor{level},
&GzipDecompressor{},
}
}
func NewGzipCompressorWithLevel(level int) Compressor {
return &gzipCompressor{level}
}
type gzipCompressor struct {
compressionLevel int
}
func (gc *gzipCompressor) Writer(w io.Writer) (io.WriteCloser, error) {
return gzip.NewWriterLevel(w, gc.compressionLevel)
}
func (gc *gzipCompressor) WriteTOCAndFooter(w io.Writer, off int64, toc *JTOC, diffHash hash.Hash) (digest.Digest, error) {
tocJSON, err := json.MarshalIndent(toc, "", "\t")
if err != nil {
return "", err
}
gz, _ := gzip.NewWriterLevel(w, gc.compressionLevel)
gw := io.Writer(gz)
if diffHash != nil {
gw = io.MultiWriter(gz, diffHash)
}
tw := tar.NewWriter(gw)
if err := tw.WriteHeader(&tar.Header{
Typeflag: tar.TypeReg,
Name: TOCTarName,
Size: int64(len(tocJSON)),
}); err != nil {
return "", err
}
if _, err := tw.Write(tocJSON); err != nil {
return "", err
}
if err := tw.Close(); err != nil {
return "", err
}
if err := gz.Close(); err != nil {
return "", err
}
if _, err := w.Write(gzipFooterBytes(off)); err != nil {
return "", err
}
return digest.FromBytes(tocJSON), nil
}
// gzipFooterBytes returns the 51 bytes footer.
func gzipFooterBytes(tocOff int64) []byte {
buf := bytes.NewBuffer(make([]byte, 0, FooterSize))
gz, _ := gzip.NewWriterLevel(buf, gzip.NoCompression) // MUST be NoCompression to keep 51 bytes
// Extra header indicating the offset of TOCJSON
// https://tools.ietf.org/html/rfc1952#section-2.3.1.1
header := make([]byte, 4)
header[0], header[1] = 'S', 'G'
subfield := fmt.Sprintf("%016xSTARGZ", tocOff)
binary.LittleEndian.PutUint16(header[2:4], uint16(len(subfield))) // little-endian per RFC1952
gz.Header.Extra = append(header, []byte(subfield)...)
gz.Close()
if buf.Len() != FooterSize {
panic(fmt.Sprintf("footer buffer = %d, not %d", buf.Len(), FooterSize))
}
return buf.Bytes()
}
type GzipDecompressor struct{}
func (gz *GzipDecompressor) Reader(r io.Reader) (io.ReadCloser, error) {
return gzip.NewReader(r)
}
func (gz *GzipDecompressor) ParseTOC(r io.Reader) (toc *JTOC, tocDgst digest.Digest, err error) {
return parseTOCEStargz(r)
}
func (gz *GzipDecompressor) ParseFooter(p []byte) (tocOffset, tocSize int64, err error) {
if len(p) != FooterSize {
return 0, 0, fmt.Errorf("invalid length %d cannot be parsed", len(p))
}
zr, err := gzip.NewReader(bytes.NewReader(p))
if err != nil {
return 0, 0, err
}
defer zr.Close()
extra := zr.Header.Extra
si1, si2, subfieldlen, subfield := extra[0], extra[1], extra[2:4], extra[4:]
if si1 != 'S' || si2 != 'G' {
return 0, 0, fmt.Errorf("invalid subfield IDs: %q, %q; want E, S", si1, si2)
}
if slen := binary.LittleEndian.Uint16(subfieldlen); slen != uint16(16+len("STARGZ")) {
return 0, 0, fmt.Errorf("invalid length of subfield %d; want %d", slen, 16+len("STARGZ"))
}
if string(subfield[16:]) != "STARGZ" {
return 0, 0, fmt.Errorf("STARGZ magic string must be included in the footer subfield")
}
tocOffset, err = strconv.ParseInt(string(subfield[:16]), 16, 64)
if err != nil {
return 0, 0, errors.Wrapf(err, "legacy: failed to parse toc offset")
}
return tocOffset, 0, nil
}
func (gz *GzipDecompressor) FooterSize() int64 {
return FooterSize
}
type legacyGzipDecompressor struct{}
func (gz *legacyGzipDecompressor) Reader(r io.Reader) (io.ReadCloser, error) {
return gzip.NewReader(r)
}
func (gz *legacyGzipDecompressor) ParseTOC(r io.Reader) (toc *JTOC, tocDgst digest.Digest, err error) {
return parseTOCEStargz(r)
}
func (gz *legacyGzipDecompressor) ParseFooter(p []byte) (tocOffset, tocSize int64, err error) {
if len(p) != legacyFooterSize {
return 0, 0, fmt.Errorf("legacy: invalid length %d cannot be parsed", len(p))
}
zr, err := gzip.NewReader(bytes.NewReader(p))
if err != nil {
return 0, 0, errors.Wrapf(err, "legacy: failed to get footer gzip reader")
}
defer zr.Close()
extra := zr.Header.Extra
if len(extra) != 16+len("STARGZ") {
return 0, 0, fmt.Errorf("legacy: invalid stargz's extra field size")
}
if string(extra[16:]) != "STARGZ" {
return 0, 0, fmt.Errorf("legacy: magic string STARGZ not found")
}
tocOffset, err = strconv.ParseInt(string(extra[:16]), 16, 64)
if err != nil {
return 0, 0, errors.Wrapf(err, "legacy: failed to parse toc offset")
}
return tocOffset, 0, nil
}
func (gz *legacyGzipDecompressor) FooterSize() int64 {
return legacyFooterSize
}
func parseTOCEStargz(r io.Reader) (toc *JTOC, tocDgst digest.Digest, err error) {
zr, err := gzip.NewReader(r)
if err != nil {
return nil, "", fmt.Errorf("malformed TOC gzip header: %v", err)
}
defer zr.Close()
zr.Multistream(false)
tr := tar.NewReader(zr)
h, err := tr.Next()
if err != nil {
return nil, "", fmt.Errorf("failed to find tar header in TOC gzip stream: %v", err)
}
if h.Name != TOCTarName {
return nil, "", fmt.Errorf("TOC tar entry had name %q; expected %q", h.Name, TOCTarName)
}
dgstr := digest.Canonical.Digester()
toc = new(JTOC)
if err := json.NewDecoder(io.TeeReader(tr, dgstr.Hash())).Decode(&toc); err != nil {
return nil, "", fmt.Errorf("error decoding TOC JSON: %v", err)
}
return toc, dgstr.Digest(), nil
}

1933
vendor/github.com/containerd/stargz-snapshotter/estargz/testutil.go generated vendored Normal file
View File

File diff suppressed because it is too large Load Diff

314
vendor/github.com/containerd/stargz-snapshotter/estargz/types.go generated vendored Normal file
View File

@@ -0,0 +1,314 @@
/*
Copyright The containerd Authors.
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.
*/
/*
Copyright 2019 The Go Authors. All rights reserved.
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file.
*/
package estargz
import (
"archive/tar"
"hash"
"io"
"os"
"path"
"time"
digest "github.com/opencontainers/go-digest"
)
const (
// TOCTarName is the name of the JSON file in the tar archive in the
// table of contents gzip stream.
TOCTarName = "stargz.index.json"
// FooterSize is the number of bytes in the footer
//
// The footer is an empty gzip stream with no compression and an Extra
// header of the form "%016xSTARGZ", where the 64 bit hex-encoded
// number is the offset to the gzip stream of JSON TOC.
//
// 51 comes from:
//
// 10 bytes gzip header
// 2 bytes XLEN (length of Extra field) = 26 (4 bytes header + 16 hex digits + len("STARGZ"))
// 2 bytes Extra: SI1 = 'S', SI2 = 'G'
// 2 bytes Extra: LEN = 22 (16 hex digits + len("STARGZ"))
// 22 bytes Extra: subfield = fmt.Sprintf("%016xSTARGZ", offsetOfTOC)
// 5 bytes flate header
// 8 bytes gzip footer
// (End of the eStargz blob)
//
// NOTE: For Extra fields, subfield IDs SI1='S' SI2='G' is used for eStargz.
FooterSize = 51
// legacyFooterSize is the number of bytes in the legacy stargz footer.
//
// 47 comes from:
//
// 10 byte gzip header +
// 2 byte (LE16) length of extra, encoding 22 (16 hex digits + len("STARGZ")) == "\x16\x00" +
// 22 bytes of extra (fmt.Sprintf("%016xSTARGZ", tocGzipOffset))
// 5 byte flate header
// 8 byte gzip footer (two little endian uint32s: digest, size)
legacyFooterSize = 47
// TOCJSONDigestAnnotation is an annotation for an image layer. This stores the
// digest of the TOC JSON.
// This annotation is valid only when it is specified in `.[]layers.annotations`
// of an image manifest.
TOCJSONDigestAnnotation = "containerd.io/snapshot/stargz/toc.digest"
// StoreUncompressedSizeAnnotation is an additional annotation key for eStargz to enable lazy
// pulling on containers/storage. Stargz Store is required to expose the layer's uncompressed size
// to the runtime but current OCI image doesn't ship this information by default. So we store this
// to the special annotation.
StoreUncompressedSizeAnnotation = "io.containers.estargz.uncompressed-size"
// PrefetchLandmark is a file entry which indicates the end position of
// prefetch in the stargz file.
PrefetchLandmark = ".prefetch.landmark"
// NoPrefetchLandmark is a file entry which indicates that no prefetch should
// occur in the stargz file.
NoPrefetchLandmark = ".no.prefetch.landmark"
landmarkContents = 0xf
)
// JTOC is the JSON-serialized table of contents index of the files in the stargz file.
type JTOC struct {
Version int `json:"version"`
Entries []*TOCEntry `json:"entries"`
}
// TOCEntry is an entry in the stargz file's TOC (Table of Contents).
type TOCEntry struct {
// Name is the tar entry's name. It is the complete path
// stored in the tar file, not just the base name.
Name string `json:"name"`
// Type is one of "dir", "reg", "symlink", "hardlink", "char",
// "block", "fifo", or "chunk".
// The "chunk" type is used for regular file data chunks past the first
// TOCEntry; the 2nd chunk and on have only Type ("chunk"), Offset,
// ChunkOffset, and ChunkSize populated.
Type string `json:"type"`
// Size, for regular files, is the logical size of the file.
Size int64 `json:"size,omitempty"`
// ModTime3339 is the modification time of the tar entry. Empty
// means zero or unknown. Otherwise it's in UTC RFC3339
// format. Use the ModTime method to access the time.Time value.
ModTime3339 string `json:"modtime,omitempty"`
modTime time.Time
// LinkName, for symlinks and hardlinks, is the link target.
LinkName string `json:"linkName,omitempty"`
// Mode is the permission and mode bits.
Mode int64 `json:"mode,omitempty"`
// UID is the user ID of the owner.
UID int `json:"uid,omitempty"`
// GID is the group ID of the owner.
GID int `json:"gid,omitempty"`
// Uname is the username of the owner.
//
// In the serialized JSON, this field may only be present for
// the first entry with the same UID.
Uname string `json:"userName,omitempty"`
// Gname is the group name of the owner.
//
// In the serialized JSON, this field may only be present for
// the first entry with the same GID.
Gname string `json:"groupName,omitempty"`
// Offset, for regular files, provides the offset in the
// stargz file to the file's data bytes. See ChunkOffset and
// ChunkSize.
Offset int64 `json:"offset,omitempty"`
nextOffset int64 // the Offset of the next entry with a non-zero Offset
// DevMajor is the major device number for "char" and "block" types.
DevMajor int `json:"devMajor,omitempty"`
// DevMinor is the major device number for "char" and "block" types.
DevMinor int `json:"devMinor,omitempty"`
// NumLink is the number of entry names pointing to this entry.
// Zero means one name references this entry.
NumLink int
// Xattrs are the extended attribute for the entry.
Xattrs map[string][]byte `json:"xattrs,omitempty"`
// Digest stores the OCI checksum for regular files payload.
// It has the form "sha256:abcdef01234....".
Digest string `json:"digest,omitempty"`
// ChunkOffset is non-zero if this is a chunk of a large,
// regular file. If so, the Offset is where the gzip header of
// ChunkSize bytes at ChunkOffset in Name begin.
//
// In serialized form, a "chunkSize" JSON field of zero means
// that the chunk goes to the end of the file. After reading
// from the stargz TOC, though, the ChunkSize is initialized
// to a non-zero file for when Type is either "reg" or
// "chunk".
ChunkOffset int64 `json:"chunkOffset,omitempty"`
ChunkSize int64 `json:"chunkSize,omitempty"`
// ChunkDigest stores an OCI digest of the chunk. This must be formed
// as "sha256:0123abcd...".
ChunkDigest string `json:"chunkDigest,omitempty"`
children map[string]*TOCEntry
}
// ModTime returns the entry's modification time.
func (e *TOCEntry) ModTime() time.Time { return e.modTime }
// NextOffset returns the position (relative to the start of the
// stargz file) of the next gzip boundary after e.Offset.
func (e *TOCEntry) NextOffset() int64 { return e.nextOffset }
func (e *TOCEntry) addChild(baseName string, child *TOCEntry) {
if e.children == nil {
e.children = make(map[string]*TOCEntry)
}
if child.Type == "dir" {
e.NumLink++ // Entry ".." in the subdirectory links to this directory
}
e.children[baseName] = child
}
// isDataType reports whether TOCEntry is a regular file or chunk (something that
// contains regular file data).
func (e *TOCEntry) isDataType() bool { return e.Type == "reg" || e.Type == "chunk" }
// Stat returns a FileInfo value representing e.
func (e *TOCEntry) Stat() os.FileInfo { return fileInfo{e} }
// ForeachChild calls f for each child item. If f returns false, iteration ends.
// If e is not a directory, f is not called.
func (e *TOCEntry) ForeachChild(f func(baseName string, ent *TOCEntry) bool) {
for name, ent := range e.children {
if !f(name, ent) {
return
}
}
}
// LookupChild returns the directory e's child by its base name.
func (e *TOCEntry) LookupChild(baseName string) (child *TOCEntry, ok bool) {
child, ok = e.children[baseName]
return
}
// fileInfo implements os.FileInfo using the wrapped *TOCEntry.
type fileInfo struct{ e *TOCEntry }
var _ os.FileInfo = fileInfo{}
func (fi fileInfo) Name() string { return path.Base(fi.e.Name) }
func (fi fileInfo) IsDir() bool { return fi.e.Type == "dir" }
func (fi fileInfo) Size() int64 { return fi.e.Size }
func (fi fileInfo) ModTime() time.Time { return fi.e.ModTime() }
func (fi fileInfo) Sys() interface{} { return fi.e }
func (fi fileInfo) Mode() (m os.FileMode) {
// TOCEntry.Mode is tar.Header.Mode so we can understand the these bits using `tar` pkg.
m = (&tar.Header{Mode: fi.e.Mode}).FileInfo().Mode() &
(os.ModePerm | os.ModeSetuid | os.ModeSetgid | os.ModeSticky)
switch fi.e.Type {
case "dir":
m |= os.ModeDir
case "symlink":
m |= os.ModeSymlink
case "char":
m |= os.ModeDevice | os.ModeCharDevice
case "block":
m |= os.ModeDevice
case "fifo":
m |= os.ModeNamedPipe
}
return m
}
// TOCEntryVerifier holds verifiers that are usable for verifying chunks contained
// in a eStargz blob.
type TOCEntryVerifier interface {
// Verifier provides a content verifier that can be used for verifying the
// contents of the specified TOCEntry.
Verifier(ce *TOCEntry) (digest.Verifier, error)
}
// Compression provides the compression helper to be used creating and parsing eStargz.
// This package provides gzip-based Compression by default, but any compression
// algorithm (e.g. zstd) can be used as long as it implements Compression.
type Compression interface {
Compressor
Decompressor
}
// Compressor represents the helper mothods to be used for creating eStargz.
type Compressor interface {
// Writer returns WriteCloser to be used for writing a chunk to eStargz.
// Everytime a chunk is written, the WriteCloser is closed and Writer is
// called again for writing the next chunk.
Writer(w io.Writer) (io.WriteCloser, error)
// WriteTOCAndFooter is called to write JTOC to the passed Writer.
// diffHash calculates the DiffID (uncompressed sha256 hash) of the blob
// WriteTOCAndFooter can optionally write anything that affects DiffID calculation
// (e.g. uncompressed TOC JSON).
//
// This function returns tocDgst that represents the digest of TOC that will be used
// to verify this blob when it's parsed.
WriteTOCAndFooter(w io.Writer, off int64, toc *JTOC, diffHash hash.Hash) (tocDgst digest.Digest, err error)
}
// Deompressor represents the helper mothods to be used for parsing eStargz.
type Decompressor interface {
// Reader returns ReadCloser to be used for decompressing file payload.
Reader(r io.Reader) (io.ReadCloser, error)
// FooterSize returns the size of the footer of this blob.
FooterSize() int64
// ParseFooter parses the footer and returns the offset and (compressed) size of TOC.
//
// Here, tocSize is optional. If tocSize <= 0, it's by default the size of the range
// from tocOffset until the beginning of the footer (blob size - tocOff - FooterSize).
ParseFooter(p []byte) (tocOffset, tocSize int64, err error)
// ParseTOC parses TOC from the passed reader. The reader provides the partial contents
// of the underlying blob that has the range specified by ParseFooter method.
//
// This function returns tocDgst that represents the digest of TOC that will be used
// to verify this blob. This must match to the value returned from
// Compressor.WriteTOCAndFooter that is used when creating this blob.
ParseTOC(r io.Reader) (toc *JTOC, tocDgst digest.Digest, err error)
}