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package copy
import (
"encoding/base64"
"encoding/json"
"net/http"
"os"
"path/filepath"
"strings"
"time"
"github.com/pkg/errors"
)
// XDockerContainerPathStatHeader is the *key* in http headers pointing to the
// base64 encoded JSON payload of stating a path in a container.
const XDockerContainerPathStatHeader = "X-Docker-Container-Path-Stat"
// ENOENT mimics the stdlib's ENOENT and can be used to implement custom logic
// while preserving the user-visible error message.
var ENOENT = errors.New("No such file or directory")
// FileInfo describes a file or directory and is returned by
// (*CopyItem).Stat().
type FileInfo struct {
Name string `json:"name"`
Size int64 `json:"size"`
Mode os.FileMode `json:"mode"`
ModTime time.Time `json:"mtime"`
IsDir bool `json:"isDir"`
LinkTarget string `json:"linkTarget"`
}
// EncodeFileInfo serializes the specified FileInfo as a base64 encoded JSON
// payload. Intended for Docker compat.
func EncodeFileInfo(info *FileInfo) (string, error) {
buf, err := json.Marshal(&info)
if err != nil {
return "", errors.Wrap(err, "failed to serialize file stats")
}
return base64.URLEncoding.EncodeToString(buf), nil
}
// ExtractFileInfoFromHeader extracts a base64 encoded JSON payload of a
// FileInfo in the http header. If no such header entry is found, nil is
// returned. Intended for Docker compat.
func ExtractFileInfoFromHeader(header *http.Header) (*FileInfo, error) {
rawData := header.Get(XDockerContainerPathStatHeader)
if len(rawData) == 0 {
return nil, nil
}
info := FileInfo{}
base64Decoder := base64.NewDecoder(base64.URLEncoding, strings.NewReader(rawData))
if err := json.NewDecoder(base64Decoder).Decode(&info); err != nil {
return nil, err
}
return &info, nil
}
// ResolveHostPath resolves the specified, possibly relative, path on the host.
func ResolveHostPath(path string) (*FileInfo, error) {
resolvedHostPath, err := filepath.Abs(path)
if err != nil {
return nil, err
}
resolvedHostPath = PreserveBasePath(path, resolvedHostPath)
statInfo, err := os.Stat(resolvedHostPath)
if err != nil {
if os.IsNotExist(err) {
return nil, ENOENT
}
return nil, err
}
return &FileInfo{
Name: statInfo.Name(),
Size: statInfo.Size(),
Mode: statInfo.Mode(),
ModTime: statInfo.ModTime(),
IsDir: statInfo.IsDir(),
LinkTarget: resolvedHostPath,
}, nil
}
// PreserveBasePath makes sure that the original base path (e.g., "/" or "./")
// is preserved. The filepath API among tends to clean up a bit too much but
// we *must* preserve this data by all means.
func PreserveBasePath(original, resolved string) string {
// Handle "/"
if strings.HasSuffix(original, "/") {
if !strings.HasSuffix(resolved, "/") {
resolved += "/"
}
return resolved
}
// Handle "/."
if strings.HasSuffix(original, "/.") {
if strings.HasSuffix(resolved, "/") { // could be root!
resolved += "."
} else if !strings.HasSuffix(resolved, "/.") {
resolved += "/."
}
return resolved
}
return resolved
}
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