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moby--moby/archive/changes.go
2013-11-08 02:48:52 +00:00

230 lines
5 KiB
Go

package archive
import (
"fmt"
"os"
"path/filepath"
"strings"
"syscall"
)
type ChangeType int
const (
ChangeModify = iota
ChangeAdd
ChangeDelete
)
type Change struct {
Path string
Kind ChangeType
}
func (change *Change) String() string {
var kind string
switch change.Kind {
case ChangeModify:
kind = "C"
case ChangeAdd:
kind = "A"
case ChangeDelete:
kind = "D"
}
return fmt.Sprintf("%s %s", kind, change.Path)
}
func Changes(layers []string, rw string) ([]Change, error) {
var changes []Change
err := filepath.Walk(rw, func(path string, f os.FileInfo, err error) error {
if err != nil {
return err
}
// Rebase path
path, err = filepath.Rel(rw, path)
if err != nil {
return err
}
path = filepath.Join("/", path)
// Skip root
if path == "/" {
return nil
}
// Skip AUFS metadata
if matched, err := filepath.Match("/.wh..wh.*", path); err != nil || matched {
return err
}
change := Change{
Path: path,
}
// Find out what kind of modification happened
file := filepath.Base(path)
// If there is a whiteout, then the file was removed
if strings.HasPrefix(file, ".wh.") {
originalFile := file[len(".wh."):]
change.Path = filepath.Join(filepath.Dir(path), originalFile)
change.Kind = ChangeDelete
} else {
// Otherwise, the file was added
change.Kind = ChangeAdd
// ...Unless it already existed in a top layer, in which case, it's a modification
for _, layer := range layers {
stat, err := os.Stat(filepath.Join(layer, path))
if err != nil && !os.IsNotExist(err) {
return err
}
if err == nil {
// The file existed in the top layer, so that's a modification
// However, if it's a directory, maybe it wasn't actually modified.
// If you modify /foo/bar/baz, then /foo will be part of the changed files only because it's the parent of bar
if stat.IsDir() && f.IsDir() {
if f.Size() == stat.Size() && f.Mode() == stat.Mode() && f.ModTime() == stat.ModTime() {
// Both directories are the same, don't record the change
return nil
}
}
change.Kind = ChangeModify
break
}
}
}
// Record change
changes = append(changes, change)
return nil
})
if err != nil && !os.IsNotExist(err) {
return nil, err
}
return changes, nil
}
func ChangesDirs(newDir, oldDir string) ([]Change, error) {
var changes []Change
err := filepath.Walk(newDir, func(newPath string, f os.FileInfo, err error) error {
if err != nil {
return err
}
var newStat syscall.Stat_t
err = syscall.Lstat(newPath, &newStat)
if err != nil {
return err
}
// Rebase path
relPath, err := filepath.Rel(newDir, newPath)
if err != nil {
return err
}
relPath = filepath.Join("/", relPath)
// Skip root
if relPath == "/" || relPath == "/.docker-id" {
return nil
}
change := Change{
Path: relPath,
}
oldPath := filepath.Join(oldDir, relPath)
var oldStat = &syscall.Stat_t{}
err = syscall.Lstat(oldPath, oldStat)
if err != nil {
if !os.IsNotExist(err) {
return err
}
oldStat = nil
}
if oldStat == nil {
change.Kind = ChangeAdd
changes = append(changes, change)
} else {
if oldStat.Ino != newStat.Ino ||
oldStat.Mode != newStat.Mode ||
oldStat.Uid != newStat.Uid ||
oldStat.Gid != newStat.Gid ||
oldStat.Rdev != newStat.Rdev ||
oldStat.Size != newStat.Size ||
oldStat.Blocks != newStat.Blocks ||
oldStat.Mtim != newStat.Mtim ||
oldStat.Ctim != newStat.Ctim {
change.Kind = ChangeModify
changes = append(changes, change)
}
}
return nil
})
if err != nil {
return nil, err
}
err = filepath.Walk(oldDir, func(oldPath string, f os.FileInfo, err error) error {
if err != nil {
return err
}
// Rebase path
relPath, err := filepath.Rel(oldDir, oldPath)
if err != nil {
return err
}
relPath = filepath.Join("/", relPath)
// Skip root
if relPath == "/" {
return nil
}
change := Change{
Path: relPath,
}
newPath := filepath.Join(newDir, relPath)
var newStat = &syscall.Stat_t{}
err = syscall.Lstat(newPath, newStat)
if err != nil && os.IsNotExist(err) {
change.Kind = ChangeDelete
changes = append(changes, change)
}
return nil
})
if err != nil {
return nil, err
}
return changes, nil
}
func ExportChanges(root, rw string) (Archive, error) {
changes, err := ChangesDirs(root, rw)
if err != nil {
return nil, err
}
files := make([]string, 0)
deletions := make([]string, 0)
for _, change := range changes {
if change.Kind == ChangeModify || change.Kind == ChangeAdd {
files = append(files, change.Path)
}
if change.Kind == ChangeDelete {
base := filepath.Base(change.Path)
dir := filepath.Dir(change.Path)
deletions = append(deletions, filepath.Join(dir, ".wh."+base))
}
}
return TarFilter(root, Uncompressed, files, false, deletions)
}