From fb8396518921eb5ab5bc413674f56f76f92d2daa Mon Sep 17 00:00:00 2001
From: Leo Antunes <leo@costela.net>
Date: Wed, 7 Feb 2024 12:07:48 +0100
Subject: [PATCH] feat: add experimental iterator

---
 iterator.go   | 41 +++++++++++++++++++++++++++++++++++++++++
 pagination.go | 20 ++++++++++++--------
 2 files changed, 53 insertions(+), 8 deletions(-)
 create mode 100644 iterator.go

diff --git a/iterator.go b/iterator.go
new file mode 100644
index 000000000..914864767
--- /dev/null
+++ b/iterator.go
@@ -0,0 +1,41 @@
+//go:build go1.22 && goexperiment.rangefunc
+// +build go1.22,goexperiment.rangefunc
+
+package gitlab
+
+import (
+	"iter"
+)
+
+// PageIterator is an EXPERIMENTAL iterator as defined in the "rangefunc" experiment for go 1.22.
+// See https://go.dev/wiki/RangefuncExperiment for more details.
+//
+// It can be used as:
+//
+//	for user, err := range gitlab.PageIterator(gl.Users.List, nil) {
+//		if err != nil {
+//			// handle error
+//		}
+//		// process individual user
+//	}
+func PageIterator[O, T any](f Paginatable[O, T], opt *O, optFunc ...RequestOptionFunc) iter.Seq2[*T, error] {
+	return func(yield func(*T, error) bool) {
+		nextLink := ""
+		for {
+			page, resp, err := f(opt, append(optFunc, WithKeysetPaginationParameters(nextLink))...)
+			if err != nil {
+				yield(nil, err)
+				return
+			}
+			for _, p := range page {
+				if !yield(p, nil) {
+					return
+				}
+			}
+			if resp.NextLink == "" {
+				break
+			}
+			nextLink = resp.NextLink
+		}
+	}
+}
diff --git a/pagination.go b/pagination.go
index 0bfb0f561..910afc559 100644
--- a/pagination.go
+++ b/pagination.go
@@ -6,18 +6,22 @@ package gitlab
 //
 // It is also possible to specify additional pagination parameters:
 //
-//	mrs, err := gitlab.AllPages(gl.MergeRequests.ListMergeRequests, &gitlab.ListMergeRequestsOptions{
-//		ListOptions: gitlab.ListOptions{
-//			PerPage:    100,
-//			Pagination: "keyset",
-//			OrderBy:    "created_at",
+//	mrs, err := gitlab.AllPages(
+//		gl.MergeRequests.ListMergeRequests,
+//		&gitlab.ListMergeRequestsOptions{
+//			ListOptions: gitlab.ListOptions{
+//				PerPage:    100,
+//				Pagination: "keyset",
+//				OrderBy:    "created_at",
+//			},
 //		},
-//	})
-func AllPages[O, T any](f Paginatable[O, T], opt *O) ([]*T, error) {
+//		gitlab.WithContext(ctx),
+//	)
+func AllPages[O, T any](f Paginatable[O, T], opt *O, optFunc ...RequestOptionFunc) ([]*T, error) {
 	all := make([]*T, 0)
 	nextLink := ""
 	for {
-		page, resp, err := f(opt, WithKeysetPaginationParameters(nextLink))
+		page, resp, err := f(opt, append(optFunc, WithKeysetPaginationParameters(nextLink))...)
 		if err != nil {
 			return nil, err
 		}