/
extractor.go
108 lines (94 loc) · 2.21 KB
/
extractor.go
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package tar
import (
"archive/tar"
"io"
"os"
fp "path/filepath"
"strings"
)
type Extractor struct {
Path string
}
func (te *Extractor) Extract(reader io.Reader) error {
tarReader := tar.NewReader(reader)
// Check if the output path already exists, so we know whether we should
// create our output with that name, or if we should put the output inside
// a preexisting directory
exists := true
pathIsDir := false
if stat, err := os.Stat(te.Path); err != nil && os.IsNotExist(err) {
exists = false
} else if err != nil {
return err
} else if stat.IsDir() {
pathIsDir = true
}
// files come recursively in order (i == 0 is root directory)
for i := 0; ; i++ {
header, err := tarReader.Next()
if err != nil && err != io.EOF {
return err
}
if header == nil || err == io.EOF {
break
}
if header.Typeflag == tar.TypeDir {
err = te.extractDir(header, i, exists)
if err != nil {
return err
}
continue
}
err = te.extractFile(header, tarReader, i, exists, pathIsDir)
if err != nil {
return err
}
}
return nil
}
func (te *Extractor) extractDir(h *tar.Header, depth int, exists bool) error {
pathElements := strings.Split(h.Name, "/")
if !exists {
pathElements = pathElements[1:]
}
path := fp.Join(pathElements...)
path = fp.Join(te.Path, path)
if depth == 0 {
// if this is the root root directory, use it as the output path for remaining files
te.Path = path
}
err := os.MkdirAll(path, 0755)
if err != nil {
return err
}
return nil
}
func (te *Extractor) extractFile(h *tar.Header, r *tar.Reader, depth int, exists bool, pathIsDir bool) error {
var path string
if depth == 0 {
// if depth is 0, this is the only file (we aren't 'ipfs get'ing a directory)
switch {
case exists && !pathIsDir:
return os.ErrExist
case exists && pathIsDir:
path = fp.Join(te.Path, h.Name)
case !exists:
path = te.Path
}
} else {
// we are outputting a directory, this file is inside of it
pathElements := strings.Split(h.Name, "/")[1:]
path = fp.Join(pathElements...)
path = fp.Join(te.Path, path)
}
file, err := os.Create(path)
if err != nil {
return err
}
defer file.Close()
_, err = io.Copy(file, r)
if err != nil {
return err
}
return nil
}