147 lines
3.8 KiB
Go
147 lines
3.8 KiB
Go
package tools
|
|
|
|
import (
|
|
"bytes"
|
|
"crypto/sha256"
|
|
"encoding/hex"
|
|
"hash"
|
|
"io"
|
|
"io/ioutil"
|
|
"os"
|
|
|
|
"github.com/git-lfs/git-lfs/errors"
|
|
"github.com/git-lfs/git-lfs/progress"
|
|
)
|
|
|
|
const (
|
|
// memoryBufferLimit is the number of bytes to buffer in memory before
|
|
// spooling the contents of an `io.Reader` in `Spool()` to a temporary
|
|
// file on disk.
|
|
memoryBufferLimit = 1024
|
|
)
|
|
|
|
// CopyWithCallback copies reader to writer while performing a progress callback
|
|
func CopyWithCallback(writer io.Writer, reader io.Reader, totalSize int64, cb progress.CopyCallback) (int64, error) {
|
|
if success, _ := CloneFile(writer, reader); success {
|
|
if cb != nil {
|
|
cb(totalSize, totalSize, 0)
|
|
}
|
|
return totalSize, nil
|
|
}
|
|
if cb == nil {
|
|
return io.Copy(writer, reader)
|
|
}
|
|
|
|
cbReader := &progress.CallbackReader{
|
|
C: cb,
|
|
TotalSize: totalSize,
|
|
Reader: reader,
|
|
}
|
|
return io.Copy(writer, cbReader)
|
|
}
|
|
|
|
// Get a new Hash instance of the type used to hash LFS content
|
|
func NewLfsContentHash() hash.Hash {
|
|
return sha256.New()
|
|
}
|
|
|
|
// HashingReader wraps a reader and calculates the hash of the data as it is read
|
|
type HashingReader struct {
|
|
reader io.Reader
|
|
hasher hash.Hash
|
|
}
|
|
|
|
func NewHashingReader(r io.Reader) *HashingReader {
|
|
return &HashingReader{r, NewLfsContentHash()}
|
|
}
|
|
|
|
func NewHashingReaderPreloadHash(r io.Reader, hash hash.Hash) *HashingReader {
|
|
return &HashingReader{r, hash}
|
|
}
|
|
|
|
func (r *HashingReader) Hash() string {
|
|
return hex.EncodeToString(r.hasher.Sum(nil))
|
|
}
|
|
|
|
func (r *HashingReader) Read(b []byte) (int, error) {
|
|
w, err := r.reader.Read(b)
|
|
if err == nil || err == io.EOF {
|
|
_, e := r.hasher.Write(b[0:w])
|
|
if e != nil && err == nil {
|
|
return w, e
|
|
}
|
|
}
|
|
|
|
return w, err
|
|
}
|
|
|
|
// RetriableReader wraps a error response of reader as RetriableError()
|
|
type RetriableReader struct {
|
|
reader io.Reader
|
|
}
|
|
|
|
func NewRetriableReader(r io.Reader) io.Reader {
|
|
return &RetriableReader{r}
|
|
}
|
|
|
|
func (r *RetriableReader) Read(b []byte) (int, error) {
|
|
n, err := r.reader.Read(b)
|
|
|
|
// EOF is a successful response as it is used to signal a graceful end
|
|
// of input c.f. https://git.io/v6riQ
|
|
//
|
|
// Otherwise, if the error is non-nil and already retriable (in the
|
|
// case that the underlying reader `r.reader` is itself a
|
|
// `*RetriableReader`, return the error wholesale:
|
|
if err == nil || err == io.EOF || errors.IsRetriableError(err) {
|
|
return n, err
|
|
}
|
|
|
|
return n, errors.NewRetriableError(err)
|
|
}
|
|
|
|
// Spool spools the contents from 'from' to 'to' by buffering the entire
|
|
// contents of 'from' into a temprorary buffer. That buffer is held in memory
|
|
// until the file grows to larger than 'memoryBufferLimit`, then the remaining
|
|
// contents are spooled to disk.
|
|
//
|
|
// The temporary file is cleaned up after the copy is complete.
|
|
//
|
|
// The number of bytes written to "to", as well as any error encountered are
|
|
// returned.
|
|
func Spool(to io.Writer, from io.Reader) (n int64, err error) {
|
|
// First, buffer up to `memoryBufferLimit` in memory.
|
|
buf := make([]byte, memoryBufferLimit)
|
|
if bn, err := from.Read(buf); err != nil && err != io.EOF {
|
|
return int64(bn), err
|
|
} else {
|
|
buf = buf[:bn]
|
|
}
|
|
|
|
var spool io.Reader = bytes.NewReader(buf)
|
|
if err != io.EOF {
|
|
// If we weren't at the end of the stream, create a temporary
|
|
// file, and spool the remaining contents there.
|
|
tmp, err := ioutil.TempFile("", "")
|
|
if err != nil {
|
|
return 0, errors.Wrap(err, "spool tmp")
|
|
}
|
|
defer os.Remove(tmp.Name())
|
|
|
|
if n, err = io.Copy(tmp, from); err != nil {
|
|
return n, errors.Wrap(err, "unable to spool")
|
|
}
|
|
|
|
if _, err = tmp.Seek(0, io.SeekStart); err != nil {
|
|
return 0, errors.Wrap(err, "unable to seek")
|
|
}
|
|
|
|
// The spooled contents will now be the concatenation of the
|
|
// contents we stored in memory, then the remainder of the
|
|
// contents on disk.
|
|
spool = io.MultiReader(spool, tmp)
|
|
}
|
|
|
|
return io.Copy(to, spool)
|
|
}
|