move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/session/tdesktop/file_test.go

@@ -0,0 +1,146 @@
+package tdesktop
+
+import (
+	"bytes"
+	"encoding/binary"
+	"io"
+	"io/fs"
+	"testing"
+	"testing/fstest"
+
+	"github.com/stretchr/testify/require"
+)
+
+var (
+	testBytes = bytes.Repeat([]byte("abcd"), 4)
+	zeros     = make([]byte, 32)
+)
+
+func Test_open(t *testing.T) {
+	b := bytes.NewBuffer(nil)
+	if err := writeFile(b, testBytes, [4]byte{}); err != nil {
+		t.Fatal(err)
+	}
+
+	tests := []struct {
+		name     string
+		fs       fs.FS
+		fileName string
+		wantErr  bool
+	}{
+		{"Empty", fstest.MapFS{}, "testfile", true},
+		{"SkipInvalidLength", fstest.MapFS{
+			// open should skip first file and read next
+			"testfile0": &fstest.MapFile{
+				Data: zeros[:4],
+			},
+			"testfile1": &fstest.MapFile{
+				Data: b.Bytes(),
+			},
+		}, "testfile", false},
+		{"SkipInvalidMagic", fstest.MapFS{
+			// open should skip first file and read next
+			"testfile0": &fstest.MapFile{
+				Data: zeros,
+			},
+			"testfile1": &fstest.MapFile{
+				Data: b.Bytes(),
+			},
+		}, "testfile", false},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			a := require.New(t)
+			if _, err := open(tt.fs, tt.fileName); tt.wantErr {
+				a.Error(err)
+			} else {
+				a.NoError(err)
+			}
+		})
+	}
+}
+
+func Test_fromFile(t *testing.T) {
+	justBytes := func(data []byte, datas ...[]byte) func() io.Reader {
+		return func() (r io.Reader) {
+			r = bytes.NewReader(data)
+			for _, d := range datas {
+				r = io.MultiReader(r, bytes.NewReader(d))
+			}
+			return r
+		}
+	}
+
+	tests := []struct {
+		name    string
+		data    func() io.Reader
+		wantErr bool
+	}{
+		{"Empty", justBytes(nil), true},
+		{"InvalidMagic", justBytes(zeros), true},
+		{"InvalidLength", justBytes(tdesktopFileMagic[:], zeros[:8]), true},
+		{"InvalidHash", justBytes(tdesktopFileMagic[:], zeros), true},
+		{"WriteFile", func() io.Reader {
+			b := bytes.NewBuffer(nil)
+			if err := writeFile(b, testBytes, [4]byte{}); err != nil {
+				t.Fatal(err)
+			}
+			return b
+		}, false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			a := require.New(t)
+			if r, err := fromFile(tt.data()); tt.wantErr {
+				a.Error(err)
+			} else {
+				a.NoError(err)
+				a.Equal(testBytes, r.data)
+			}
+		})
+	}
+}
+
+func Test_telegramFileHash(t *testing.T) {
+	data := bytes.Repeat([]byte{'a'}, 100)
+	expected := [16]uint8{
+		0xa8, 0xa9, 0xa1, 0x38,
+		0xcf, 0x32, 0x37, 0xa9,
+		0x4b, 0x78, 0xd0, 0x2d,
+		0x03, 0xe0, 0x16, 0x81,
+	}
+	require.Equal(t, expected, telegramFileHash(data, [4]byte{0, 0, 0, 1}))
+}
+
+func Test_readArray(t *testing.T) {
+	var validData bytes.Buffer
+	if err := writeArray(&validData, testBytes, binary.LittleEndian); err != nil {
+		t.Fatal(err)
+	}
+
+	tests := []struct {
+		name    string
+		data    []byte
+		expect  []byte
+		order   binary.ByteOrder
+		wantErr bool
+	}{
+		{"LengthEOF", nil, nil, binary.LittleEndian, true},
+		{"DataEOF", []byte{255, 0, 0, 0}, nil, binary.LittleEndian, true},
+		{"OK", validData.Bytes(), testBytes, binary.LittleEndian, false},
+		{"0xffffffff", []byte{0xff, 0xff, 0xff, 0xff}, nil, binary.LittleEndian, false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			a := require.New(t)
+			if data, n, err := readArray(tt.data, tt.order); tt.wantErr {
+				a.Error(err)
+			} else {
+				a.NoError(err)
+				a.Equal(len(tt.expect)+4, n)
+				a.Equal(tt.expect, data)
+			}
+		})
+	}
+}