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package pktline_test
import (
"bytes"
"errors"
"fmt"
"io"
"strings"
"github.com/go-git/go-git/v5/plumbing/format/pktline"
. "gopkg.in/check.v1"
)
type SuiteScanner struct{}
var _ = Suite(&SuiteScanner{})
func (s *SuiteScanner) TestInvalid(c *C) {
for _, test := range [...]string{
"0001", "0002", "0003", "0004",
"0001asdfsadf", "0004foo",
"fff5", "ffff",
"gorka",
"0", "003",
" 5a", "5 a", "5 \n",
"-001", "-000",
} {
r := strings.NewReader(test)
sc := pktline.NewScanner(r)
_ = sc.Scan()
c.Assert(sc.Err(), ErrorMatches, pktline.ErrInvalidPktLen.Error(),
Commentf("data = %q", test))
}
}
func (s *SuiteScanner) TestDecodeOversizePktLines(c *C) {
for _, test := range [...]string{
"fff1" + strings.Repeat("a", 0xfff1),
"fff2" + strings.Repeat("a", 0xfff2),
"fff3" + strings.Repeat("a", 0xfff3),
"fff4" + strings.Repeat("a", 0xfff4),
} {
r := strings.NewReader(test)
sc := pktline.NewScanner(r)
_ = sc.Scan()
c.Assert(sc.Err(), IsNil)
}
}
func (s *SuiteScanner) TestEmptyReader(c *C) {
r := strings.NewReader("")
sc := pktline.NewScanner(r)
hasPayload := sc.Scan()
c.Assert(hasPayload, Equals, false)
c.Assert(sc.Err(), Equals, nil)
}
func (s *SuiteScanner) TestFlush(c *C) {
var buf bytes.Buffer
e := pktline.NewEncoder(&buf)
err := e.Flush()
c.Assert(err, IsNil)
sc := pktline.NewScanner(&buf)
c.Assert(sc.Scan(), Equals, true)
payload := sc.Bytes()
c.Assert(len(payload), Equals, 0)
}
func (s *SuiteScanner) TestPktLineTooShort(c *C) {
r := strings.NewReader("010cfoobar")
sc := pktline.NewScanner(r)
c.Assert(sc.Scan(), Equals, false)
c.Assert(sc.Err(), ErrorMatches, "unexpected EOF")
}
func (s *SuiteScanner) TestScanAndPayload(c *C) {
for _, test := range [...]string{
"a",
"a\n",
strings.Repeat("a", 100),
strings.Repeat("a", 100) + "\n",
strings.Repeat("\x00", 100),
strings.Repeat("\x00", 100) + "\n",
strings.Repeat("a", pktline.MaxPayloadSize),
strings.Repeat("a", pktline.MaxPayloadSize-1) + "\n",
} {
var buf bytes.Buffer
e := pktline.NewEncoder(&buf)
err := e.EncodeString(test)
c.Assert(err, IsNil,
Commentf("input len=%x, contents=%.10q\n", len(test), test))
sc := pktline.NewScanner(&buf)
c.Assert(sc.Scan(), Equals, true,
Commentf("test = %.20q...", test))
obtained := sc.Bytes()
c.Assert(obtained, DeepEquals, []byte(test),
Commentf("in = %.20q out = %.20q", test, string(obtained)))
}
}
func (s *SuiteScanner) TestSkip(c *C) {
for _, test := range [...]struct {
input []string
n int
expected []byte
}{
{
input: []string{
"first",
"second",
"third"},
n: 1,
expected: []byte("second"),
},
{
input: []string{
"first",
"second",
"third"},
n: 2,
expected: []byte("third"),
},
} {
var buf bytes.Buffer
e := pktline.NewEncoder(&buf)
err := e.EncodeString(test.input...)
c.Assert(err, IsNil)
sc := pktline.NewScanner(&buf)
for i := 0; i < test.n; i++ {
c.Assert(sc.Scan(), Equals, true,
Commentf("scan error = %s", sc.Err()))
}
c.Assert(sc.Scan(), Equals, true,
Commentf("scan error = %s", sc.Err()))
obtained := sc.Bytes()
c.Assert(obtained, DeepEquals, test.expected,
Commentf("\nin = %.20q\nout = %.20q\nexp = %.20q",
test.input, obtained, test.expected))
}
}
func (s *SuiteScanner) TestEOF(c *C) {
var buf bytes.Buffer
e := pktline.NewEncoder(&buf)
err := e.EncodeString("first", "second")
c.Assert(err, IsNil)
sc := pktline.NewScanner(&buf)
for sc.Scan() {
}
c.Assert(sc.Err(), IsNil)
}
type mockReader struct{}
func (r *mockReader) Read([]byte) (int, error) { return 0, errors.New("foo") }
func (s *SuiteScanner) TestInternalReadError(c *C) {
sc := pktline.NewScanner(&mockReader{})
c.Assert(sc.Scan(), Equals, false)
c.Assert(sc.Err(), ErrorMatches, "foo")
}
// A section are several non flush-pkt lines followed by a flush-pkt, which
// how the git protocol sends long messages.
func (s *SuiteScanner) TestReadSomeSections(c *C) {
nSections := 2
nLines := 4
data := sectionsExample(c, nSections, nLines)
sc := pktline.NewScanner(data)
sectionCounter := 0
lineCounter := 0
for sc.Scan() {
if len(sc.Bytes()) == 0 {
sectionCounter++
}
lineCounter++
}
c.Assert(sc.Err(), IsNil)
c.Assert(sectionCounter, Equals, nSections)
c.Assert(lineCounter, Equals, (1+nLines)*nSections)
}
// returns nSection sections, each of them with nLines pkt-lines (not
// counting the flush-pkt:
//
// 0009 0.0\n
// 0009 0.1\n
// ...
// 0000
// and so on
func sectionsExample(c *C, nSections, nLines int) io.Reader {
var buf bytes.Buffer
e := pktline.NewEncoder(&buf)
for section := 0; section < nSections; section++ {
ss := []string{}
for line := 0; line < nLines; line++ {
line := fmt.Sprintf(" %d.%d\n", section, line)
ss = append(ss, line)
}
err := e.EncodeString(ss...)
c.Assert(err, IsNil)
err = e.Flush()
c.Assert(err, IsNil)
}
return &buf
}
func ExampleScanner() {
// A reader is needed as input.
input := strings.NewReader("000ahello\n" +
"000bworld!\n" +
"0000",
)
// Create the scanner...
s := pktline.NewScanner(input)
// and scan every pkt-line found in the input.
for s.Scan() {
payload := s.Bytes()
if len(payload) == 0 { // zero sized payloads correspond to flush-pkts.
fmt.Println("FLUSH-PKT DETECTED")
} else { // otherwise, you will be able to access the full payload.
fmt.Printf("PAYLOAD = %q\n", string(payload))
}
}
// this will catch any error when reading from the input, if any.
if s.Err() != nil {
fmt.Println(s.Err())
}
// Output:
// PAYLOAD = "hello\n"
// PAYLOAD = "world!\n"
// FLUSH-PKT DETECTED
}
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