vendor

vendor/github.com/cavaliercoder/go-cpio/header.go

@@ -0,0 +1,152 @@
+package cpio
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"time"
+)
+
+// Mode constants from the cpio spec.
+const (
+	ModeSetuid     = 04000   // Set uid
+	ModeSetgid     = 02000   // Set gid
+	ModeSticky     = 01000   // Save text (sticky bit)
+	ModeDir        = 040000  // Directory
+	ModeNamedPipe  = 010000  // FIFO
+	ModeRegular    = 0100000 // Regular file
+	ModeSymlink    = 0120000 // Symbolic link
+	ModeDevice     = 060000  // Block special file
+	ModeCharDevice = 020000  // Character special file
+	ModeSocket     = 0140000 // Socket
+
+	ModeType = 0170000 // Mask for the type bits
+	ModePerm = 0777    // Unix permission bits
+)
+
+const (
+	// headerEOF is the value of the filename of the last header in a CPIO archive.
+	headerEOF = "TRAILER!!!"
+)
+
+var (
+	ErrHeader = errors.New("cpio: invalid cpio header")
+)
+
+// A FileMode represents a file's mode and permission bits.
+type FileMode int64
+
+func (m FileMode) String() string {
+	return fmt.Sprintf("%#o", m)
+}
+
+// IsDir reports whether m describes a directory. That is, it tests for the
+// ModeDir bit being set in m.
+func (m FileMode) IsDir() bool {
+	return m&ModeDir != 0
+}
+
+// IsRegular reports whether m describes a regular file. That is, it tests for
+// the ModeRegular bit being set in m.
+func (m FileMode) IsRegular() bool {
+	return m&^ModePerm == ModeRegular
+}
+
+// Perm returns the Unix permission bits in m.
+func (m FileMode) Perm() FileMode {
+	return m & ModePerm
+}
+
+// Checksum is the sum of all bytes	in the file data. This sum is computed
+// treating all bytes as unsigned values and using unsigned arithmetic. Only
+// the least-significant 32 bits of the sum are stored. Use NewHash to compute
+// the actual checksum of an archived file.
+type Checksum uint32
+
+func (c Checksum) String() string {
+	return fmt.Sprintf("%08X", uint32(c))
+}
+
+// A Header represents a single header in a CPIO archive.
+type Header struct {
+	DeviceID int
+	Inode    int64     // inode number
+	Mode     FileMode  // permission and mode bits
+	UID      int       // user id of the owner
+	GID      int       // group id of the owner
+	Links    int       // number of inbound links
+	ModTime  time.Time // modified time
+	Size     int64     // size in bytes
+	Name     string    // filename
+	Linkname string    // target name of link
+	Checksum Checksum  // computed checksum
+
+	pad int64 // bytes to pad before next header
+}
+
+// FileInfo returns an os.FileInfo for the Header.
+func (h *Header) FileInfo() os.FileInfo {
+	return headerFileInfo{h}
+}
+
+// FileInfoHeader creates a partially-populated Header from fi.
+// If fi describes a symlink, FileInfoHeader records link as the link target.
+// If fi describes a directory, a slash is appended to the name.
+// 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.
+func FileInfoHeader(fi os.FileInfo, link string) (*Header, error) {
+	if fi == nil {
+		return nil, errors.New("cpio: FileInfo is nil")
+	}
+
+	if sys, ok := fi.Sys().(*Header); ok {
+		// This FileInfo came from a Header (not the OS). Return a copy of the
+		// original Header.
+		h := &Header{}
+		*h = *sys
+		return h, nil
+	}
+
+	fm := fi.Mode()
+	h := &Header{
+		Name:    fi.Name(),
+		Mode:    FileMode(fi.Mode().Perm()), // or'd with Mode* constants later
+		ModTime: fi.ModTime(),
+		Size:    fi.Size(),
+	}
+
+	switch {
+	case fm.IsRegular():
+		h.Mode |= ModeRegular
+	case fi.IsDir():
+		h.Mode |= ModeDir
+		h.Name += "/"
+	case fm&os.ModeSymlink != 0:
+		h.Mode |= ModeSymlink
+		h.Linkname = link
+	case fm&os.ModeDevice != 0:
+		if fm&os.ModeCharDevice != 0 {
+			h.Mode |= ModeCharDevice
+		} else {
+			h.Mode |= ModeDevice
+		}
+	case fm&os.ModeNamedPipe != 0:
+		h.Mode |= ModeNamedPipe
+	case fm&os.ModeSocket != 0:
+		h.Mode |= ModeSocket
+	default:
+		return nil, fmt.Errorf("cpio: unknown file mode %v", fm)
+	}
+	if fm&os.ModeSetuid != 0 {
+		h.Mode |= ModeSetuid
+	}
+	if fm&os.ModeSetgid != 0 {
+		h.Mode |= ModeSetgid
+	}
+	if fm&os.ModeSticky != 0 {
+		h.Mode |= ModeSticky
+	}
+
+	return h, nil
+}