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/cmd/mtprint/printer.go

@@ -0,0 +1,130 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+
+	"github.com/go-faster/errors"
+	"github.com/k0kubun/pp/v3"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/mt"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/proto/codec"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tdp"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tmap"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/transport"
+)
+
+// Object is abstraction for TL schema object.
+type Object interface {
+	bin.Object
+	tdp.Object
+}
+
+// Formatter formats given bin.Object and prints it to io.Writer.
+type Formatter interface {
+	Format(w io.Writer, i Object) error
+}
+
+// FormatterFunc is functional adapter for Formatter.
+type FormatterFunc func(w io.Writer, i Object) error
+
+// Format implements Formatter.
+func (f FormatterFunc) Format(w io.Writer, i Object) error {
+	return f(w, i)
+}
+
+func formats(name string) Formatter {
+	switch name {
+	case "json":
+		return FormatterFunc(func(w io.Writer, i Object) error {
+			e := json.NewEncoder(w)
+			e.SetIndent("", "\t")
+			return e.Encode(i)
+		})
+	case "pp":
+		return FormatterFunc(func(w io.Writer, i Object) error {
+			_, err := pp.Fprintln(w, i)
+			return err
+		})
+	case "tdp":
+		return FormatterFunc(func(w io.Writer, i Object) error {
+			_, err := io.WriteString(w, tdp.Format(i))
+			return err
+		})
+	default: // "go" format
+		return FormatterFunc(func(w io.Writer, i Object) error {
+			_, err := fmt.Fprintln(w, i)
+			return err
+		})
+	}
+}
+
+// Printer decodes messages from given reader and prints is using Formatter.
+type Printer struct {
+	src    io.Reader
+	codec  transport.Codec
+	format Formatter
+}
+
+// NewPrinter creates new Printer.
+// If format is nil, "go" format will be used.
+// If c is nil, codec.Intermediate will be use.
+func NewPrinter(src io.Reader, format Formatter, c transport.Codec) Printer {
+	if c == nil {
+		c = codec.Intermediate{}
+	}
+	if format == nil {
+		format = formats("go")
+	}
+	return Printer{
+		src:    src,
+		codec:  c,
+		format: format,
+	}
+}
+
+// Print prints decoded messages to output.
+func (p Printer) Print(output io.Writer) error {
+	b := &bin.Buffer{}
+
+	m := tmap.NewConstructor(
+		tg.TypesConstructorMap(),
+		mt.TypesConstructorMap(),
+	)
+	for {
+		b.Reset()
+		if err := p.codec.Read(p.src, b); err != nil {
+			if errors.Is(err, io.EOF) {
+				return nil
+			}
+
+			return err
+		}
+
+		id, err := b.PeekID()
+		if err != nil {
+			return err
+		}
+
+		obj := m.New(id)
+		if obj == nil {
+			return errors.Errorf("find type %#x", id)
+		}
+
+		v, ok := obj.(Object)
+		if !ok {
+			return errors.Errorf("unexpected type %T", obj)
+		}
+
+		if err := v.Decode(b); err != nil {
+			return err
+		}
+
+		if err := p.format.Format(output, v); err != nil {
+			return err
+		}
+	}
+}