libgo: update to Go1.10beta1

    
    Update the Go library to the 1.10beta1 release.
    
    Requires a few changes to the compiler for modifications to the map
    runtime code, and to handle some nowritebarrier cases in the runtime.
    
    Reviewed-on: https://go-review.googlesource.com/86455

gotools/:
	* Makefile.am (go_cmd_vet_files): New variable.
	(go_cmd_buildid_files, go_cmd_test2json_files): New variables.
	(s-zdefaultcc): Change from constants to functions.
	(noinst_PROGRAMS): Add vet, buildid, and test2json.
	(cgo$(EXEEXT)): Link against $(LIBGOTOOL).
	(vet$(EXEEXT)): New target.
	(buildid$(EXEEXT)): New target.
	(test2json$(EXEEXT)): New target.
	(install-exec-local): Install all $(noinst_PROGRAMS).
	(uninstall-local): Uninstasll all $(noinst_PROGRAMS).
	(check-go-tool): Depend on $(noinst_PROGRAMS).  Copy down
	objabi.go.
	(check-runtime): Depend on $(noinst_PROGRAMS).
	(check-cgo-test, check-carchive-test): Likewise.
	(check-vet): New target.
	(check): Depend on check-vet.  Look at cmd_vet-testlog.
	(.PHONY): Add check-vet.
	* Makefile.in: Rebuild.

From-SVN: r256365

2 files changed, 176 insertions, 38 deletions

diff --git a/libgo/go/encoding/hex/hex.go b/libgo/go/encoding/hex/hex.go
index 2768f1b..e4df6cb 100644
--- a/libgo/go/encoding/hex/hex.go
+++ b/libgo/go/encoding/hex/hex.go
@@ -31,7 +31,9 @@ func Encode(dst, src []byte) int {
 	return len(src) * 2
 }
 
-// ErrLength results from decoding an odd length slice.
+// ErrLength reports an attempt to decode an odd-length input
+// using Decode or DecodeString.
+// The stream-based Decoder returns io.ErrUnexpectedEOF instead of ErrLength.
 var ErrLength = errors.New("encoding/hex: odd length hex string")
 
 // InvalidByteError values describe errors resulting from an invalid byte in a hex string.
@@ -50,24 +52,30 @@ func DecodedLen(x int) int { return x / 2 }
 //
 // Decode expects that src contain only hexadecimal
 // characters and that src should have an even length.
+// If the input is malformed, Decode returns the number
+// of bytes decoded before the error.
 func Decode(dst, src []byte) (int, error) {
-	if len(src)%2 == 1 {
-		return 0, ErrLength
-	}
-
-	for i := 0; i < len(src)/2; i++ {
+	var i int
+	for i = 0; i < len(src)/2; i++ {
 		a, ok := fromHexChar(src[i*2])
 		if !ok {
-			return 0, InvalidByteError(src[i*2])
+			return i, InvalidByteError(src[i*2])
 		}
 		b, ok := fromHexChar(src[i*2+1])
 		if !ok {
-			return 0, InvalidByteError(src[i*2+1])
+			return i, InvalidByteError(src[i*2+1])
 		}
 		dst[i] = (a << 4) | b
 	}
-
-	return len(src) / 2, nil
+	if len(src)%2 == 1 {
+		// Check for invalid char before reporting bad length,
+		// since the invalid char (if present) is an earlier problem.
+		if _, ok := fromHexChar(src[i*2]); !ok {
+			return i, InvalidByteError(src[i*2])
+		}
+		return i, ErrLength
+	}
+	return i, nil
 }
 
 // fromHexChar converts a hex character into its value and a success flag.
@@ -92,14 +100,17 @@ func EncodeToString(src []byte) string {
 }
 
 // DecodeString returns the bytes represented by the hexadecimal string s.
+//
+// DecodeString expects that src contain only hexadecimal
+// characters and that src should have an even length.
+// If the input is malformed, DecodeString returns a string
+// containing the bytes decoded before the error.
 func DecodeString(s string) ([]byte, error) {
 	src := []byte(s)
-	dst := make([]byte, DecodedLen(len(src)))
-	_, err := Decode(dst, src)
-	if err != nil {
-		return nil, err
-	}
-	return dst, nil
+	// We can use the source slice itself as the destination
+	// because the decode loop increments by one and then the 'seen' byte is not used anymore.
+	n, err := Decode(src, src)
+	return src[:n], err
 }
 
 // Dump returns a string that contains a hex dump of the given data. The format
@@ -112,6 +123,81 @@ func Dump(data []byte) string {
 	return buf.String()
 }
 
+// bufferSize is the number of hexadecimal characters to buffer in encoder and decoder.
+const bufferSize = 1024
+
+type encoder struct {
+	w   io.Writer
+	err error
+	out [bufferSize]byte // output buffer
+}
+
+// NewEncoder returns an io.Writer that writes lowercase hexadecimal characters to w.
+func NewEncoder(w io.Writer) io.Writer {
+	return &encoder{w: w}
+}
+
+func (e *encoder) Write(p []byte) (n int, err error) {
+	for len(p) > 0 && e.err == nil {
+		chunkSize := bufferSize / 2
+		if len(p) < chunkSize {
+			chunkSize = len(p)
+		}
+
+		var written int
+		encoded := Encode(e.out[:], p[:chunkSize])
+		written, e.err = e.w.Write(e.out[:encoded])
+		n += written / 2
+		p = p[chunkSize:]
+	}
+	return n, e.err
+}
+
+type decoder struct {
+	r   io.Reader
+	err error
+	in  []byte           // input buffer (encoded form)
+	arr [bufferSize]byte // backing array for in
+}
+
+// NewDecoder returns an io.Reader that decodes hexadecimal characters from r.
+// NewDecoder expects that r contain only an even number of hexadecimal characters.
+func NewDecoder(r io.Reader) io.Reader {
+	return &decoder{r: r}
+}
+
+func (d *decoder) Read(p []byte) (n int, err error) {
+	// Fill internal buffer with sufficient bytes to decode
+	if len(d.in) < 2 && d.err == nil {
+		var numCopy, numRead int
+		numCopy = copy(d.arr[:], d.in) // Copies either 0 or 1 bytes
+		numRead, d.err = d.r.Read(d.arr[numCopy:])
+		d.in = d.arr[:numCopy+numRead]
+		if d.err == io.EOF && len(d.in)%2 != 0 {
+			if _, ok := fromHexChar(d.in[len(d.in)-1]); !ok {
+				d.err = InvalidByteError(d.in[len(d.in)-1])
+			} else {
+				d.err = io.ErrUnexpectedEOF
+			}
+		}
+	}
+
+	// Decode internal buffer into output buffer
+	if numAvail := len(d.in) / 2; len(p) > numAvail {
+		p = p[:numAvail]
+	}
+	numDec, err := Decode(p, d.in[:len(p)*2])
+	d.in = d.in[2*numDec:]
+	if err != nil {
+		d.in, d.err = nil, err // Decode error; discard input remainder
+	}
+
+	if len(d.in) < 2 {
+		return numDec, d.err // Only expose errors when buffer fully consumed
+	}
+	return numDec, nil
+}
+
 // Dumper returns a WriteCloser that writes a hex dump of all written data to
 // w. The format of the dump matches the output of `hexdump -C` on the command
 // line.
diff --git a/libgo/go/encoding/hex/hex_test.go b/libgo/go/encoding/hex/hex_test.go
index 64dabbd..b6bab21 100644
--- a/libgo/go/encoding/hex/hex_test.go
+++ b/libgo/go/encoding/hex/hex_test.go
@@ -7,6 +7,9 @@ package hex
 import (
 	"bytes"
 	"fmt"
+	"io"
+	"io/ioutil"
+	"strings"
 	"testing"
 )
 
@@ -75,37 +78,86 @@ func TestDecodeString(t *testing.T) {
 	}
 }
 
-type errTest struct {
+var errTests = []struct {
 	in  string
-	err string
+	out string
+	err error
+}{
+	{"", "", nil},
+	{"0", "", ErrLength},
+	{"zd4aa", "", InvalidByteError('z')},
+	{"d4aaz", "\xd4\xaa", InvalidByteError('z')},
+	{"30313", "01", ErrLength},
+	{"0g", "", InvalidByteError('g')},
+	{"00gg", "\x00", InvalidByteError('g')},
+	{"0\x01", "", InvalidByteError('\x01')},
+	{"ffeed", "\xff\xee", ErrLength},
 }
 
-var errTests = []errTest{
-	{"0", "encoding/hex: odd length hex string"},
-	{"0g", "encoding/hex: invalid byte: U+0067 'g'"},
-	{"00gg", "encoding/hex: invalid byte: U+0067 'g'"},
-	{"0\x01", "encoding/hex: invalid byte: U+0001"},
+func TestDecodeErr(t *testing.T) {
+	for _, tt := range errTests {
+		out := make([]byte, len(tt.in)+10)
+		n, err := Decode(out, []byte(tt.in))
+		if string(out[:n]) != tt.out || err != tt.err {
+			t.Errorf("Decode(%q) = %q, %v, want %q, %v", tt.in, string(out[:n]), err, tt.out, tt.err)
+		}
+	}
 }
 
-func TestInvalidErr(t *testing.T) {
-	for i, test := range errTests {
-		dst := make([]byte, DecodedLen(len(test.in)))
-		_, err := Decode(dst, []byte(test.in))
-		if err == nil {
-			t.Errorf("#%d: expected error; got none", i)
-		} else if err.Error() != test.err {
-			t.Errorf("#%d: got: %v want: %v", i, err, test.err)
+func TestDecodeStringErr(t *testing.T) {
+	for _, tt := range errTests {
+		out, err := DecodeString(tt.in)
+		if string(out) != tt.out || err != tt.err {
+			t.Errorf("DecodeString(%q) = %q, %v, want %q, %v", tt.in, out, err, tt.out, tt.err)
+		}
+	}
+}
+
+func TestEncoderDecoder(t *testing.T) {
+	for _, multiplier := range []int{1, 128, 192} {
+		for _, test := range encDecTests {
+			input := bytes.Repeat(test.dec, multiplier)
+			output := strings.Repeat(test.enc, multiplier)
+
+			var buf bytes.Buffer
+			enc := NewEncoder(&buf)
+			r := struct{ io.Reader }{bytes.NewReader(input)} // io.Reader only; not io.WriterTo
+			if n, err := io.CopyBuffer(enc, r, make([]byte, 7)); n != int64(len(input)) || err != nil {
+				t.Errorf("encoder.Write(%q*%d) = (%d, %v), want (%d, nil)", test.dec, multiplier, n, err, len(input))
+				continue
+			}
+
+			if encDst := buf.String(); encDst != output {
+				t.Errorf("buf(%q*%d) = %v, want %v", test.dec, multiplier, encDst, output)
+				continue
+			}
+
+			dec := NewDecoder(&buf)
+			var decBuf bytes.Buffer
+			w := struct{ io.Writer }{&decBuf} // io.Writer only; not io.ReaderFrom
+			if _, err := io.CopyBuffer(w, dec, make([]byte, 7)); err != nil || decBuf.Len() != len(input) {
+				t.Errorf("decoder.Read(%q*%d) = (%d, %v), want (%d, nil)", test.enc, multiplier, decBuf.Len(), err, len(input))
+			}
+
+			if !bytes.Equal(decBuf.Bytes(), input) {
+				t.Errorf("decBuf(%q*%d) = %v, want %v", test.dec, multiplier, decBuf.Bytes(), input)
+				continue
+			}
 		}
 	}
 }
 
-func TestInvalidStringErr(t *testing.T) {
-	for i, test := range errTests {
-		_, err := DecodeString(test.in)
-		if err == nil {
-			t.Errorf("#%d: expected error; got none", i)
-		} else if err.Error() != test.err {
-			t.Errorf("#%d: got: %v want: %v", i, err, test.err)
+func TestDecoderErr(t *testing.T) {
+	for _, tt := range errTests {
+		dec := NewDecoder(strings.NewReader(tt.in))
+		out, err := ioutil.ReadAll(dec)
+		wantErr := tt.err
+		// Decoder is reading from stream, so it reports io.ErrUnexpectedEOF instead of ErrLength.
+		if wantErr == ErrLength {
+			wantErr = io.ErrUnexpectedEOF
+		}
+		if string(out) != tt.out || err != wantErr {
+			t.Errorf("NewDecoder(%q) = %q, %v, want %q, %v", tt.in, out, err, tt.out, wantErr)
 		}
 	}
 }