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/tdjson/decoder.go

@@ -0,0 +1,198 @@
+package tdjson
+
+import (
+	"encoding/base64"
+	"encoding/hex"
+
+	"github.com/go-faster/errors"
+	"github.com/go-faster/jx"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+)
+
+// Decoder is a simple wrapper around jx.Decoder to conform TL type system.
+type Decoder struct {
+	*jx.Decoder
+}
+
+// Obj calls f for every key in object, using byte slice as key.
+//
+// The key value is valid only until f is not returned.
+func (b Decoder) Obj(cb func(d Decoder, key []byte) error) error {
+	return b.Decoder.ObjBytes(func(d *jx.Decoder, key []byte) error {
+		return cb(Decoder{Decoder: d}, key)
+	})
+}
+
+// Arr decodes array and invokes callback on each array element.
+func (b Decoder) Arr(cb func(d Decoder) error) error {
+	return b.Decoder.Arr(func(d *jx.Decoder) error {
+		return cb(Decoder{Decoder: d})
+	})
+}
+
+// ID deserializes given typeID.
+func (b Decoder) ID() (string, error) {
+	return b.Decoder.Str()
+}
+
+// FindTypeID tries to find @type field or returns error.
+func (b Decoder) FindTypeID() (string, error) {
+	var (
+		found bool
+		typ   string
+	)
+	if err := b.Decoder.Capture(func(d *jx.Decoder) error {
+		return d.ObjBytes(func(d *jx.Decoder, key []byte) error {
+			if found || string(key) != TypeField {
+				return d.Skip()
+			}
+
+			t, err := d.Str()
+			if err != nil {
+				return err
+			}
+			typ = t
+			found = true
+			return nil
+		})
+	}); err != nil {
+		return "", err
+	}
+	if !found {
+		return "", ErrTypeIDNotFound
+	}
+	return typ, nil
+}
+
+// ConsumeID deserializes given typeID.
+func (b Decoder) ConsumeID(id string) error {
+	v, err := b.Decoder.Str()
+	if err != nil {
+		return err
+	}
+	if v != id {
+		return NewUnexpectedID(id)
+	}
+	return nil
+}
+
+// Int deserializes signed 32-bit integer.
+func (b Decoder) Int() (int, error) {
+	return b.Decoder.Int()
+}
+
+// Bool deserializes boolean.
+func (b Decoder) Bool() (bool, error) {
+	return b.Decoder.Bool()
+}
+
+// Uint16 deserializes unsigned 16-bit integer.
+func (b Decoder) Uint16() (uint16, error) {
+	v, err := b.Decoder.UInt32()
+	if err != nil {
+		return 0, err
+	}
+	return uint16(v), nil
+}
+
+// Int32 deserializes signed 32-bit integer.
+func (b Decoder) Int32() (int32, error) {
+	return b.Decoder.Int32()
+}
+
+// Uint32 deserializes unsigned 32-bit integer.
+func (b Decoder) Uint32() (uint32, error) {
+	return b.Decoder.UInt32()
+}
+
+// Int53 deserializes int53.
+func (b Decoder) Int53() (int64, error) {
+	return b.Decoder.Int64()
+}
+
+// Long deserializes int64.
+func (b Decoder) Long() (int64, error) {
+	n, err := b.Decoder.Num()
+	if err != nil {
+		return 0, err
+	}
+	return n.Int64()
+}
+
+// Uint64 deserializes unsigned 64-bit integer.
+func (b Decoder) Uint64() (uint64, error) {
+	return b.Decoder.UInt64()
+}
+
+// Double deserializes 64-bit floating point.
+func (b Decoder) Double() (float64, error) {
+	return b.Decoder.Float64()
+}
+
+// Int128 deserializes 128-bit signed integer.
+func (b Decoder) Int128() (bin.Int128, error) {
+	// FIXME(tdakkota): neither TDLib API not Telegram API has no Int128/Int256 fields
+	// 	so this encoding may incorrect.
+	v, err := b.Decoder.Str()
+	if err != nil {
+		return bin.Int128{}, err
+	}
+
+	var result bin.Int128
+	if l := hex.DecodedLen(len(v)); l != len(result) {
+		return bin.Int128{}, errors.Wrapf(err, "invalid length %d", l)
+	}
+
+	if _, err := hex.Decode(result[:], []byte(v)); err != nil {
+		return bin.Int128{}, err
+	}
+
+	return result, nil
+}
+
+// Int256 deserializes 256-bit signed integer.
+func (b Decoder) Int256() (bin.Int256, error) {
+	// FIXME(tdakkota): neither TDLib API not Telegram API has no Int128/Int256 fields
+	// 	so this encoding may incorrect.
+	v, err := b.Decoder.StrBytes()
+	if err != nil {
+		return bin.Int256{}, err
+	}
+
+	var result bin.Int256
+	if l := hex.DecodedLen(len(v)); l != len(result) {
+		return bin.Int256{}, errors.Wrapf(err, "invalid length %d", l)
+	}
+
+	if _, err := hex.Decode(result[:], v); err != nil {
+		return bin.Int256{}, err
+	}
+
+	return result, nil
+}
+
+// String deserializes bare string.
+func (b Decoder) String() (string, error) {
+	return b.Decoder.Str()
+}
+
+// Bytes deserializes bare byte string.
+func (b Decoder) Bytes() ([]byte, error) {
+	// See https://core.telegram.org/tdlib/docs/td__json__client_8h.html
+	//
+	// ... fields of bytes type are base64 encoded and then stored as String ...
+	enc := base64.RawStdEncoding
+
+	v, err := b.Decoder.StrBytes()
+	if err != nil {
+		return nil, err
+	}
+
+	result := make([]byte, enc.DecodedLen(len(v)))
+	if _, err := enc.Decode(result, v); err != nil {
+		return nil, err
+	}
+
+	return result, nil
+}