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/telegram/query/internal/cachedgen/_template/gen.tmpl

@@ -0,0 +1,119 @@
+{{ define "header" }}{{- /*gotype: go.mau.fi/mautrix-telegram/pkg/gotd/telegram/query/internal/cachedgen.Config*/ -}}
+// Code generated by itergen, DO NOT EDIT.
+
+package {{ $.Package }}
+
+import (
+    "context"
+    "sync/atomic"
+
+    "github.com/go-faster/errors"
+
+    "go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+)
+
+// No-op definition for keeping imports.
+var _ = context.Background()
+
+{{ range $query := $.Queries }}
+
+type inner{{ $query.Name }} struct {
+    // Last received hash.
+    hash  int64
+    // Last received result.
+	value *tg.{{ $query.ResultName }}
+}
+
+type {{ $query.Name }} struct {
+    {{- if $query.RequestParams }}
+    // Query to send.
+    req *tg.{{ $query.RequestName }}{{ end }}
+    // Result state.
+    last atomic.Value
+
+    // Reference to RPC client to make requests.
+	  raw *tg.Client
+}
+
+// New{{ $query.Name }} creates new {{ $query.Name }}.
+func New{{ $query.Name }}(raw *tg.Client, {{- if $query.RequestParams }}initial *tg.{{ $query.RequestName }}{{- end }}) *{{ $query.Name }} {
+    q := &{{ $query.Name }}{
+        {{- if $query.RequestParams }}
+        req: initial,{{ end }}
+        raw: raw,
+    }
+
+    return q
+}
+
+func (s *{{ $query.Name }}) store(v inner{{ $query.Name }}) {
+    s.last.Store(v)
+}
+
+func (s *{{ $query.Name }}) load() (inner{{ $query.Name }}, bool) {
+    v, ok := s.last.Load().(inner{{ $query.Name }})
+    return v, ok
+}
+
+// Value returns last received result.
+// NB: May be nil. Returned {{ $query.ResultName }} must not be mutated.
+func (s *{{ $query.Name }}) Value() *tg.{{ $query.ResultName }} {
+	inner, _ := s.load()
+	return inner.value
+}
+
+// Hash returns last received hash.
+func (s *{{ $query.Name }}) Hash() int64 {
+    inner, _ := s.load()
+    return inner.hash
+}
+
+// Get updates data if needed and returns it.
+func (s *{{ $query.Name }}) Get(ctx context.Context) (*tg.{{ $query.ResultName }}, error) {
+    if _, err := s.Fetch(ctx); err != nil {
+        return nil, err
+    }
+
+    return s.Value(), nil
+}
+
+// Fetch updates data if needed and returns true if data was modified.
+func (s *{{ $query.Name }}) Fetch(ctx context.Context) (bool, error) {
+    lastHash := s.Hash()
+
+    {{ if $query.RequestParams -}}
+    req := s.req
+    req.Hash = lastHash
+    {{- else -}}
+    req := lastHash
+    {{- end }}
+	result, err := s.raw.{{ $query.MethodName }}(ctx, req)
+	if err != nil {
+		return false, errors.Wrap(err, "execute {{ $query.MethodName }}")
+	}
+
+	switch variant := result.(type) {
+    case *tg.{{ $query.ResultName }}:
+        {{ if $query.ManualHash -}}
+        hash := s.computeHash(variant)
+        {{- else -}}
+        hash := variant.Hash
+        {{- end }}
+
+        s.store(inner{{ $query.Name }}{
+            hash: hash,
+            value: variant,
+        })
+        return true, nil
+	case *tg.{{ $query.NotModifiedName }}:
+		if lastHash == 0 {
+			return false, errors.Errorf("got unexpected %T result", result)
+		}
+        return false, nil
+	default:
+		return false, errors.Errorf("unexpected type %T", result)
+	}
+}
+{{ end }}
+
+{{ end }}