1 files changed, 68 insertions, 0 deletions
diff --git a/internal/util/fns.go b/internal/util/fns.go
new file mode 100644
index 000000000..53f5ebeed
--- /dev/null
+++ b/internal/util/fns.go
@@ -0,0 +1,68 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// 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 <http://www.gnu.org/licenses/>.
+
+package util
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+
+	"codeberg.org/gruf/go-errors/v2"
+)
+
+// Must executes 'fn' repeatedly until
+// it successfully returns without panic.
+func Must(fn func()) {
+	if fn == nil {
+		panic("nil func")
+	}
+	for !func() (done bool) {
+		defer func() {
+			if r := recover(); r != nil {
+				// Gather calling func frames.
+				pcs := make([]uintptr, 10)
+				n := runtime.Callers(3, pcs)
+				i := runtime.CallersFrames(pcs[:n])
+				c := gatherFrames(i, n)
+
+				const msg = "recovered panic: %v\n\n%s\n"
+				fmt.Fprintf(os.Stderr, msg, r, c.String())
+			}
+		}()
+		fn()
+		done = true
+		return
+	}() { //nolint
+	}
+}
+
+// gatherFrames collates runtime frames from a frame iterator.
+func gatherFrames(iter *runtime.Frames, n int) errors.Callers {
+	if iter == nil {
+		return nil
+	}
+	frames := make([]runtime.Frame, 0, n)
+	for {
+		f, ok := iter.Next()
+		if !ok {
+			break
+		}
+		frames = append(frames, f)
+	}
+	return frames
+}