From 9beaeef3d228290e3f62879c85d2170107cc057b Mon Sep 17 00:00:00 2001
From: Veronika Rovnik <veronikarovnik@gmail.com>
Date: Tue, 6 Feb 2024 22:47:18 +0100
Subject: [PATCH] gh-682 Issue 682: add ```List::insert_after```

---
 src/internal_modules/roc_core/list.h        | 29 +++++++++++++++-----
 src/tests/roc_core/test_list_operations.cpp | 30 +++++++++++++++++++--
 2 files changed, 51 insertions(+), 8 deletions(-)

diff --git a/src/internal_modules/roc_core/list.h b/src/internal_modules/roc_core/list.h
index 7cd4b5817..d13ed780c 100644
--- a/src/internal_modules/roc_core/list.h
+++ b/src/internal_modules/roc_core/list.h
@@ -149,7 +149,7 @@ class List : public NonCopyable<> {
         if (size_ == 0) {
             insert_(element, NULL);
         } else {
-            insert_(element, container_of_(head_.next));
+            insert_(element, head_.next);
         }
     }
 
@@ -205,7 +205,26 @@ class List : public NonCopyable<> {
     //!  @p element should not be member of any list.
     //!  @p before should be member of this list or NULL.
     void insert_before(T& element, T& before) {
-        insert_(element, &before);
+        insert_(element, before.list_node_data());
+    }
+
+    //! Insert element into list.
+    //!
+    //! @remarks
+    //!  - inserts @p element after @p after
+    //!  - acquires ownership of @p element
+    //!
+    //! @pre
+    //!  @p element should not be member of any list.
+    //!  @p after should be member of this list.
+    void insert_after(T& element, T& after) {
+        ListNode::ListNodeData* data_after = after.list_node_data();
+
+        if (data_after->next == &head_) {
+            insert_(element, NULL);
+        } else {
+            insert_(element, data_after->next);
+        }
     }
 
     //! Remove element from list.
@@ -242,13 +261,11 @@ class List : public NonCopyable<> {
         }
     }
 
-    void insert_(T& element, T* before) {
+    void insert_(T& element, ListNode::ListNodeData* data_before) {
         ListNode::ListNodeData* data_new = element.list_node_data();
         check_is_member_(data_new, NULL);
 
-        ListNode::ListNodeData* data_before;
-        if (before != NULL) {
-            data_before = before->list_node_data();
+        if (data_before != NULL) {
             check_is_member_(data_before, this);
         } else {
             data_before = &head_;
diff --git a/src/tests/roc_core/test_list_operations.cpp b/src/tests/roc_core/test_list_operations.cpp
index dd9bd8bdc..194911bf8 100644
--- a/src/tests/roc_core/test_list_operations.cpp
+++ b/src/tests/roc_core/test_list_operations.cpp
@@ -167,7 +167,7 @@ TEST(list_operations, push_front_many) {
     CHECK(!list.is_empty());
 }
 
-TEST(list_operations, insert_front) {
+TEST(list_operations, insert_before_front) {
     list.push_back(objects[0]);
     list.insert_before(objects[1], *list.front());
 
@@ -178,7 +178,7 @@ TEST(list_operations, insert_front) {
     CHECK(!list.is_empty());
 }
 
-TEST(list_operations, insert_middle) {
+TEST(list_operations, insert_before_middle) {
     list.push_back(objects[0]);
     list.push_back(objects[1]);
 
@@ -193,6 +193,32 @@ TEST(list_operations, insert_middle) {
     POINTERS_EQUAL(&objects[2], list.nextof(*list.front()));
 }
 
+TEST(list_operations, insert_after_back) {
+    list.push_back(objects[0]);
+    list.insert_after(objects[1], *list.back());
+
+    POINTERS_EQUAL(&objects[0], list.front());
+    POINTERS_EQUAL(&objects[1], list.back());
+
+    LONGS_EQUAL(2, list.size());
+    CHECK(!list.is_empty());
+}
+
+TEST(list_operations, insert_after_middle) {
+    list.push_back(objects[0]);
+    list.push_back(objects[1]);
+
+    list.insert_after(objects[2], objects[0]);
+
+    POINTERS_EQUAL(&objects[0], list.front());
+    POINTERS_EQUAL(&objects[1], list.back());
+
+    LONGS_EQUAL(3, list.size());
+    CHECK(!list.is_empty());
+
+    POINTERS_EQUAL(&objects[2], list.nextof(*list.front()));
+}
+
 TEST(list_operations, remove_front) {
     for (size_t i = 0; i < NumObjects; ++i) {
         list.push_back(objects[i]);