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// Copyright 2015 The appc 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 aci
import (
"archive/tar"
"io"
"os"
"path/filepath"
"github.com/appc/spec/pkg/tarheader"
)
// TarHeaderWalkFunc is the type of the function which allows setting tar
// headers or filtering out tar entries when building an ACI. It will be
// applied to every entry in the tar file.
//
// If true is returned, the entry will be included in the final ACI; if false,
// the entry will not be included.
type TarHeaderWalkFunc func(hdr *tar.Header) bool
// BuildWalker creates a filepath.WalkFunc that walks over the given root
// (which should represent an ACI layout on disk) and adds the files in the
// rootfs/ subdirectory to the given ArchiveWriter
func BuildWalker(root string, aw ArchiveWriter, cb TarHeaderWalkFunc) filepath.WalkFunc {
// cache of inode -> filepath, used to leverage hard links in the archive
inos := map[uint64]string{}
return func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
relpath, err := filepath.Rel(root, path)
if err != nil {
return err
}
if relpath == "." {
return nil
}
if relpath == ManifestFile {
// ignore; this will be written by the archive writer
// TODO(jonboulle): does this make sense? maybe just remove from archivewriter?
return nil
}
link := ""
var r io.Reader
switch info.Mode() & os.ModeType {
case os.ModeSocket:
return nil
case os.ModeNamedPipe:
case os.ModeCharDevice:
case os.ModeDevice:
case os.ModeDir:
case os.ModeSymlink:
target, err := os.Readlink(path)
if err != nil {
return err
}
link = target
default:
file, err := os.Open(path)
if err != nil {
return err
}
defer file.Close()
r = file
}
hdr, err := tar.FileInfoHeader(info, link)
if err != nil {
panic(err)
}
// Because os.FileInfo's Name method returns only the base
// name of the file it describes, it may be necessary to
// modify the Name field of the returned header to provide the
// full path name of the file.
hdr.Name = relpath
tarheader.Populate(hdr, info, inos)
// If the file is a hard link to a file we've already seen, we
// don't need the contents
if hdr.Typeflag == tar.TypeLink {
hdr.Size = 0
r = nil
}
if cb != nil {
if !cb(hdr) {
return nil
}
}
if err := aw.AddFile(hdr, r); err != nil {
return err
}
return nil
}
}
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