113 lines
2.6 KiB
Go
113 lines
2.6 KiB
Go
package wire
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import (
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"encoding/binary"
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"fmt"
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"io"
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"os"
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"time"
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)
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type SyncScanner interface {
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// ReadOctetString reads a 4-byte string.
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ReadOctetString() (string, error)
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ReadInt32() (int32, error)
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ReadFileMode() (os.FileMode, error)
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ReadTime() (time.Time, error)
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// Reads an octet length, followed by length bytes.
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ReadString() (string, error)
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// Reads an octet length, and returns a reader that will read length
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// bytes (see io.LimitReader). The returned reader should be fully
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// read before reading anything off the Scanner again.
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ReadBytes() (io.Reader, error)
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// Closes the underlying reader.
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Close() error
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}
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type realSyncScanner struct {
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io.Reader
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}
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func NewSyncScanner(r io.Reader) SyncScanner {
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return &realSyncScanner{r}
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}
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func RequireOctetString(s SyncScanner, expected string) error {
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actual, err := s.ReadOctetString()
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if err != nil {
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return fmt.Errorf("expected to read '%s', got err: %v", expected, err)
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}
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if actual != expected {
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return fmt.Errorf("expected to read '%s', got '%s'", expected, actual)
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}
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return nil
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}
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func (s *realSyncScanner) ReadOctetString() (string, error) {
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octet := make([]byte, 4)
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n, err := io.ReadFull(s.Reader, octet)
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if err != nil && err != io.ErrUnexpectedEOF {
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return "", err
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} else if err == io.ErrUnexpectedEOF {
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return "", incompleteMessage("octet", n, 4)
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}
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return string(octet), nil
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}
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func (s *realSyncScanner) ReadInt32() (int32, error) {
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var value int32
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err := binary.Read(s.Reader, binary.LittleEndian, &value)
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return value, err
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}
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func (s *realSyncScanner) ReadFileMode() (filemode os.FileMode, err error) {
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var value uint32
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err = binary.Read(s.Reader, binary.LittleEndian, &value)
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if err == nil {
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filemode = ParseFileModeFromAdb(value)
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}
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return
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}
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func (s *realSyncScanner) ReadTime() (time.Time, error) {
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seconds, err := s.ReadInt32()
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if err != nil {
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return time.Time{}, err
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}
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return time.Unix(int64(seconds), 0).UTC(), nil
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}
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func (s *realSyncScanner) ReadString() (string, error) {
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length, err := s.ReadInt32()
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if err != nil {
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return "", err
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}
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bytes := make([]byte, length)
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n, err := io.ReadFull(s.Reader, bytes)
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if err != nil && err != io.ErrUnexpectedEOF {
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return "", err
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} else if err == io.ErrUnexpectedEOF {
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return "", incompleteMessage("bytes", n, int(length))
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}
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return string(bytes), nil
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}
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func (s *realSyncScanner) ReadBytes() (io.Reader, error) {
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length, err := s.ReadInt32()
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if err != nil {
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return nil, err
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}
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return io.LimitReader(s.Reader, int64(length)), nil
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}
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func (s *realSyncScanner) Close() error {
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if closer, ok := s.Reader.(io.Closer); ok {
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return closer.Close()
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}
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return nil
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}
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