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signed_file.go
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/
signed_file.go
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package signer
import (
"io"
"sync"
)
// nolint:gochecknoglobals // set a pool as global var
var signedFilePool = sync.Pool{New: func() interface{} {
return &SignedFile{
rc: nil,
size: 0,
bs: nil,
buf: [CommonSignChunkSize64K]byte{},
}
}}
type SignedFile struct {
rc io.ReadSeekCloser
size int64
bs *BlobSign
buf [CommonSignChunkSize64K]byte
}
func NewSignedFile(fd io.ReadSeekCloser, fsize uint64, bs *BlobSign) *SignedFile {
sf := signedFilePool.Get().(*SignedFile)
sf.rc = fd
sf.bs = bs
sf.size = int64(fsize)
return sf
}
func (f *SignedFile) Seek(offset int64, whence int) (int64, error) {
return f.rc.Seek(offset, whence)
}
func (f *SignedFile) Read(p []byte) (n int, err error) {
offset, err := f.rc.Seek(0, io.SeekCurrent)
if err != nil {
return 0, err
}
droppedSize := offset % int64(CommonSignChunkSize64K)
if _, err := f.rc.Seek(offset-droppedSize, io.SeekStart); err != nil {
return n, err
}
bufSize := len(p)
for n < bufSize {
fn, err := f.rc.Read(f.buf[:])
if err != nil && err != io.EOF {
return n, err
} else if err == io.EOF {
break
} else if fn != CommonSignChunkSize64K {
return n, ErrSignIncomplete
}
desSign := f.bs.Get(offset / CommonSignChunkSize64K)
if desSign != signCRC(f.buf[:]) {
return n, ErrSignCrc
}
cn := copy(p[n:], f.buf[droppedSize:])
offset += int64(cn)
n += cn
if _, err := f.rc.Seek(offset, io.SeekStart); err != nil {
return n, err
}
if offset >= f.size {
n -= int(offset - f.size)
return n, io.EOF
}
droppedSize = 0
}
return n, err
}
// Close will return this SignedFile to pool, after calling close, this SignedFile should never be used again.
func (f *SignedFile) Close() error {
err := f.rc.Close()
f.rc = nil
f.bs = nil
f.size = 0
signedFilePool.Put(f)
return err
}