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package remotecontext // import "github.com/docker/docker/builder/remotecontext"
import (
"os"
"sync"
"github.com/docker/docker/pkg/containerfs"
iradix "github.com/hashicorp/go-immutable-radix"
digest "github.com/opencontainers/go-digest"
"github.com/pkg/errors"
"github.com/tonistiigi/fsutil"
)
type hashed interface {
Digest() digest.Digest
}
// CachableSource is a source that contains cache records for its contents
type CachableSource struct {
mu sync.Mutex
root containerfs.ContainerFS
tree *iradix.Tree
txn *iradix.Txn
}
// NewCachableSource creates new CachableSource
func NewCachableSource(root string) *CachableSource {
ts := &CachableSource{
tree: iradix.New(),
root: containerfs.NewLocalContainerFS(root),
}
return ts
}
// MarshalBinary marshals current cache information to a byte array
func (cs *CachableSource) MarshalBinary() ([]byte, error) {
b := TarsumBackup{Hashes: make(map[string]string)}
root := cs.getRoot()
root.Walk(func(k []byte, v interface{}) bool {
b.Hashes[string(k)] = v.(*fileInfo).sum
return false
})
return b.Marshal()
}
// UnmarshalBinary decodes cache information for presented byte array
func (cs *CachableSource) UnmarshalBinary(data []byte) error {
var b TarsumBackup
if err := b.Unmarshal(data); err != nil {
return err
}
txn := iradix.New().Txn()
for p, v := range b.Hashes {
txn.Insert([]byte(p), &fileInfo{sum: v})
}
cs.mu.Lock()
defer cs.mu.Unlock()
cs.tree = txn.Commit()
return nil
}
// Scan rescans the cache information from the file system
func (cs *CachableSource) Scan() error {
lc, err := NewLazySource(cs.root)
if err != nil {
return err
}
txn := iradix.New().Txn()
err = cs.root.Walk(cs.root.Path(), func(path string, info os.FileInfo, err error) error {
if err != nil {
return errors.Wrapf(err, "failed to walk %s", path)
}
rel, err := Rel(cs.root, path)
if err != nil {
return err
}
h, err := lc.Hash(rel)
if err != nil {
return err
}
txn.Insert([]byte(rel), &fileInfo{sum: h})
return nil
})
if err != nil {
return err
}
cs.mu.Lock()
defer cs.mu.Unlock()
cs.tree = txn.Commit()
return nil
}
// HandleChange notifies the source about a modification operation
func (cs *CachableSource) HandleChange(kind fsutil.ChangeKind, p string, fi os.FileInfo, err error) (retErr error) {
cs.mu.Lock()
if cs.txn == nil {
cs.txn = cs.tree.Txn()
}
if kind == fsutil.ChangeKindDelete {
cs.txn.Delete([]byte(p))
cs.mu.Unlock()
return
}
h, ok := fi.(hashed)
if !ok {
cs.mu.Unlock()
return errors.Errorf("invalid fileinfo: %s", p)
}
hfi := &fileInfo{
sum: h.Digest().Hex(),
}
cs.txn.Insert([]byte(p), hfi)
cs.mu.Unlock()
return nil
}
func (cs *CachableSource) getRoot() *iradix.Node {
cs.mu.Lock()
if cs.txn != nil {
cs.tree = cs.txn.Commit()
cs.txn = nil
}
t := cs.tree
cs.mu.Unlock()
return t.Root()
}
// Close closes the source
func (cs *CachableSource) Close() error {
return nil
}
// Hash returns a hash for a single file in the source
func (cs *CachableSource) Hash(path string) (string, error) {
n := cs.getRoot()
// TODO: check this for symlinks
v, ok := n.Get([]byte(path))
if !ok {
return path, nil
}
return v.(*fileInfo).sum, nil
}
// Root returns a root directory for the source
func (cs *CachableSource) Root() containerfs.ContainerFS {
return cs.root
}
type fileInfo struct {
sum string
}
func (fi *fileInfo) Hash() string {
return fi.sum
}
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