Rework telegram client lifecycle to hopefully fix not stopping issues (#112)

pkg/connector/future.go

@@ -0,0 +1,51 @@
+// mautrix-telegram - A Matrix-Telegram puppeting bridge.
+// Copyright (C) 2025 Automattic Inc.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+package connector
+
+import (
+	"context"
+	"sync"
+)
+
+type Future[T any] struct {
+	value T
+	err   error
+	ready chan struct{}
+	once  sync.Once
+}
+
+func NewFuture[T any]() *Future[T] {
+	return &Future[T]{
+		ready: make(chan struct{}),
+	}
+}
+
+func (f *Future[T]) Set(value T) {
+	f.once.Do(func() {
+		f.value = value
+		close(f.ready)
+	})
+}
+
+func (f *Future[T]) Get(ctx context.Context) (T, error) {
+	select {
+	case <-f.ready:
+		return f.value, nil
+	case <-ctx.Done():
+		return f.value, ctx.Err()
+	}
+}