add AbortableScanView function (#23245)

sdk/logical/storage.go

@@ -97,6 +97,40 @@ func ScanView(ctx context.Context, view ClearableView, cb func(path string)) err
 	return nil
 }
 
+// AbortableScanView is used to scan all the keys in a view iteratively,
+// but will abort the scan if cb returns false
+func AbortableScanView(ctx context.Context, view ClearableView, cb func(path string) (cont bool)) error {
+	frontier := []string{""}
+	for len(frontier) > 0 {
+		n := len(frontier)
+		current := frontier[n-1]
+		frontier = frontier[:n-1]
+
+		// List the contents
+		contents, err := view.List(ctx, current)
+		if err != nil {
+			return errwrap.Wrapf(fmt.Sprintf("list failed at path %q: {{err}}", current), err)
+		}
+
+		// Handle the contents in the directory
+		for _, c := range contents {
+			// Exit if the context has been canceled
+			if ctx.Err() != nil {
+				return ctx.Err()
+			}
+			fullPath := current + c
+			if strings.HasSuffix(c, "/") {
+				frontier = append(frontier, fullPath)
+			} else {
+				if !cb(fullPath) {
+					return nil
+				}
+			}
+		}
+	}
+	return nil
+}
+
 // CollectKeys is used to collect all the keys in a view
 func CollectKeys(ctx context.Context, view ClearableView) ([]string, error) {
 	return CollectKeysWithPrefix(ctx, view, "")