goadb/wire/sync_scanner.go
2015-07-12 00:37:58 -07:00

116 lines
3.3 KiB
Go

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