From 7132666a635be4f6722427264dacbbaa99be7fe8 Mon Sep 17 00:00:00 2001
From: ferdymercury <ferdymercury@users.noreply.github.com>
Date: Fri, 28 Feb 2025 10:36:55 +0100
Subject: [PATCH] [core] AddBefore/After/At option variant, as with
 Add/First/Last

Fixes https://its.cern.ch/jira/browse/ROOT-9288
---
 core/cont/inc/TList.h   |   5 ++
 core/cont/src/TList.cxx | 133 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 138 insertions(+)

diff --git a/core/cont/inc/TList.h b/core/cont/inc/TList.h
index a86af707c175c..47903a107e355 100644
--- a/core/cont/inc/TList.h
+++ b/core/cont/inc/TList.h
@@ -85,10 +85,15 @@ friend  class TListIter;
    void              AddLast(TObject *obj) override;
    virtual void      AddLast(TObject *obj, Option_t *opt);
    void              AddAt(TObject *obj, Int_t idx) override;
+   void              AddAt(TObject *obj, Int_t idx, Option_t *option);
    void              AddAfter(const TObject *after, TObject *obj) override;
    virtual void      AddAfter(TObjLink *after, TObject *obj);
+   void              AddAfter(const TObject *after, TObject *obj, Option_t *option);
+   void              AddAfter(TObjLink *after, TObject *obj, Option_t *option);
    void              AddBefore(const TObject *before, TObject *obj) override;
    virtual void      AddBefore(TObjLink *before, TObject *obj);
+   void              AddBefore(const TObject *before, TObject *obj, Option_t *option);
+   void              AddBefore(TObjLink *before, TObject *obj, Option_t *option);
    TObject  *Remove(TObject *obj) override;
    virtual TObject  *Remove(TObjLink *lnk);
    TObject          *Remove(const TObjLinkPtr_t &lnk) { return Remove(lnk.get()); }
diff --git a/core/cont/src/TList.cxx b/core/cont/src/TList.cxx
index 30a4b69628d62..23f58ac42f7cd 100644
--- a/core/cont/src/TList.cxx
+++ b/core/cont/src/TList.cxx
@@ -298,6 +298,116 @@ void TList::AddAfter(TObjLink *after, TObject *obj)
    }
 }
 
+////////////////////////////////////////////////////////////////////////////////
+/// Insert object before object before in the list, with options.
+
+void TList::AddBefore(const TObject *before, TObject *obj, Option_t *option)
+{
+   R__COLLECTION_WRITE_GUARD();
+   
+   if (IsArgNull("AddBefore", obj)) return;
+   
+   R__COLLECTION_WRITE_LOCKGUARD(ROOT::gCoreMutex);
+   
+   if (!before)
+      TList::AddFirst(obj, option);
+   else {
+      Int_t    idx;
+      TObjLink *t = FindLink(before, idx);
+      if (!t) {
+         Error("AddBefore", "before not found, object not added");
+         return;
+      }
+      if (t == fFirst.get())
+         TList::AddFirst(obj, option);
+      else {
+         NewOptLink(obj, option, t->fPrev.lock());
+         fSize++;
+         Changed();
+      }
+   }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/// Insert object before the specified ObjLink object. If before = 0 then add
+/// to the head of the list. An ObjLink can be obtained by looping over a list
+/// using the above describe iterator method 3. Options can be specified.
+
+void TList::AddBefore(TObjLink *before, TObject *obj, Option_t *option)
+{
+   R__COLLECTION_WRITE_GUARD();
+   
+   if (IsArgNull("AddBefore", obj)) return;
+   
+   if (!before)
+      TList::AddFirst(obj, option);
+   else {
+      if (before == fFirst.get())
+         TList::AddFirst(obj, option);
+      else {
+         NewOptLink(obj, option, before->fPrev.lock());
+         fSize++;
+         Changed();
+      }
+   }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/// Insert object after object after in the list, with options.
+
+void TList::AddAfter(const TObject *after, TObject *obj, Option_t *option)
+{
+   R__COLLECTION_WRITE_GUARD();
+   
+   if (IsArgNull("AddAfter", obj)) return;
+   
+   R__COLLECTION_WRITE_LOCKGUARD(ROOT::gCoreMutex);
+   
+   if (!after)
+      TList::AddLast(obj, option);
+   else {
+      Int_t    idx;
+      TObjLink *t = FindLink(after, idx);
+      if (!t) {
+         Error("AddAfter", "after not found, object not added");
+         return;
+      }
+      if (t == fLast.get())
+         TList::AddLast(obj, option);
+      else {
+         NewOptLink(obj, option, t->shared_from_this());
+         fSize++;
+         Changed();
+      }
+   }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+/// Insert object after the specified ObjLink object. If after = 0 then add
+/// to the tail of the list. An ObjLink can be obtained by looping over a list
+/// using the above describe iterator method 3. Options can be specified.
+
+void TList::AddAfter(TObjLink *after, TObject *obj, Option_t *option)
+{
+   R__COLLECTION_WRITE_GUARD();
+   
+   if (IsArgNull("AddAfter", obj)) return;
+   
+   R__COLLECTION_WRITE_LOCKGUARD(ROOT::gCoreMutex);
+   
+   if (!after)
+      TList::AddLast(obj, option);
+   else {
+      if (after == fLast.get())
+         TList::AddLast(obj, option);
+      else {
+         NewOptLink(obj, option, after->shared_from_this());
+         fSize++;
+         Changed();
+      }
+   }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 /// Insert object at position idx in the list.
 
@@ -321,6 +431,29 @@ void TList::AddAt(TObject *obj, Int_t idx)
    }
 }
 
+////////////////////////////////////////////////////////////////////////////////
+/// Insert object at position idx in the list, with options.
+
+void TList::AddAt(TObject *obj, Int_t idx, Option_t *option)
+{
+   R__COLLECTION_WRITE_GUARD();
+   
+   if (IsArgNull("AddAt", obj)) return;
+   
+   R__COLLECTION_WRITE_LOCKGUARD(ROOT::gCoreMutex);
+   
+   TObjLink *lnk = LinkAt(idx);
+   if (!lnk)
+      TList::AddLast(obj, option);
+   else if (lnk == fFirst.get())
+      TList::AddFirst(obj, option);
+   else {
+      NewOptLink(obj, option, lnk->fPrev.lock());
+      fSize++;
+      Changed();
+   }
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 /// Returns the object after object obj. Obj is found using the
 /// object's IsEqual() method.  Returns 0 if obj is last in list.