[PATCH 2/2] MdePkg/BaseLib: Update internal LinkedList verifications.

[PATCH 2/2] MdePkg/BaseLib: Update internal LinkedList verifications.

[Marvin Häuser]

1) Replace InternalBaseLibIsNodeInList() with
   InternalBaseLibIsListValid().
   - The verification whether Node is within the doubly-linked List
     is now done by IsNodeInList().
   - Whether the list is valid is returned.

2) The comments within InsertHeadList() and InsertTailList() stated
   that it is checked whether Entry is not part of the doubly-linked
   list. This was not done as argument 3 of
   InternalBaseLibIsNodeInList() indicated whether the check is done,
   not whether to check if the node is or is not in the list. This
   has been fixed by using IsNodeInList() for the ASSERTs.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Marvin Haeuser <Marvin.Haeuser@outlook.com>
---
 MdePkg/Library/BaseLib/LinkedList.c | 79 +++++---------------
 1 file changed, 19 insertions(+), 60 deletions(-)

diff --git a/MdePkg/Library/BaseLib/LinkedList.c b/MdePkg/Library/BaseLib/LinkedList.c
index b364ae41c647..e3734fd85057 100644
--- a/MdePkg/Library/BaseLib/LinkedList.c
+++ b/MdePkg/Library/BaseLib/LinkedList.c
@@ -15,25 +15,15 @@
 #include "BaseLibInternals.h"
 
 /**
-  Worker function that locates the Node in the List.
-
-  By searching the List, finds the location of the Node in List. At the same time,
-  verifies the validity of this list.
+  Worker function that verifies the validity of this list.
 
   If List is NULL, then ASSERT().
   If List->ForwardLink is NULL, then ASSERT().
-  If List->backLink is NULL, then ASSERT().
-  If Node is NULL, then ASSERT().
-  If PcdVerifyNodeInList is TRUE and DoMembershipCheck is TRUE and Node 
-  is in not a member of List, then return FALSE
+  If List->BackLink is NULL, then ASSERT().
   If PcdMaximumLinkedListLength is not zero, and List contains more than
   PcdMaximumLinkedListLength nodes, then ASSERT().
 
   @param  List              A pointer to a node in a linked list.
-  @param  Node              A pointer to a node in a linked list.
-  @param  VerifyNodeInList  TRUE if a check should be made to see if Node is a 
-                            member of List.  FALSE if no membership test should 
-                            be performed.
 
   @retval   TRUE if PcdVerifyNodeInList is FALSE
   @retval   TRUE if DoMembershipCheck is FALSE
@@ -45,10 +35,8 @@
 **/
 BOOLEAN
 EFIAPI
-InternalBaseLibIsNodeInList (
-  IN CONST LIST_ENTRY  *List,
-  IN CONST LIST_ENTRY  *Node,
-  IN BOOLEAN           VerifyNodeInList
+InternalBaseLibIsListValid (
+  IN CONST LIST_ENTRY  *List
   )
 {
   UINTN             Count;
@@ -60,40 +48,11 @@ InternalBaseLibIsNodeInList (
   ASSERT (List != NULL);
   ASSERT (List->ForwardLink != NULL);
   ASSERT (List->BackLink != NULL);
-  ASSERT (Node != NULL);
-
-  Count = 0;
-  Ptr   = List;
-
-  if (FeaturePcdGet (PcdVerifyNodeInList) && VerifyNodeInList) {
-    //
-    // Check to see if Node is a member of List.  
-    // Exit early if the number of nodes in List >= PcdMaximumLinkedListLength
-    //
-    do {
-      Ptr = Ptr->ForwardLink;
-      if (PcdGet32 (PcdMaximumLinkedListLength) > 0) {
-        Count++;
-        //
-        // ASSERT() if the linked list is too long
-        //
-        ASSERT (Count < PcdGet32 (PcdMaximumLinkedListLength));
-
-        //
-        // Return if the linked list is too long
-        //
-        if (Count >= PcdGet32 (PcdMaximumLinkedListLength)) {
-          return (BOOLEAN)(Ptr == Node);
-        }
-      }
-    } while ((Ptr != List) && (Ptr != Node)); 
-
-    if (Ptr != Node) {
-      return FALSE;
-    }
-  }
 
   if (PcdGet32 (PcdMaximumLinkedListLength) > 0) {
+    Count = 0;
+    Ptr   = List;
+
     //
     // Count the total number of nodes in List.
     // Exit early if the number of nodes in List >= PcdMaximumLinkedListLength
@@ -104,9 +63,9 @@ InternalBaseLibIsNodeInList (
     } while ((Ptr != List) && (Count < PcdGet32 (PcdMaximumLinkedListLength)));
 
     //
-    // ASSERT() if the linked list is too long
+    // return whether linked list is too long
     //
-    ASSERT (Count < PcdGet32 (PcdMaximumLinkedListLength));
+    return (BOOLEAN)(Count < PcdGet32 (PcdMaximumLinkedListLength));
   }
 
   return TRUE;
@@ -150,7 +109,7 @@ IsNodeInList (
   //
   // ASSERT List not too long
   //
-  ASSERT (InternalBaseLibIsNodeInList (ListHead, Entry, FALSE));
+  ASSERT (InternalBaseLibIsListValid (List));
 
   Count = 0;
   Ptr   = List;
@@ -242,7 +201,7 @@ InsertHeadList (
   //
   // ASSERT List not too long and Entry is not one of the nodes of List
   //
-  ASSERT (InternalBaseLibIsNodeInList (ListHead, Entry, FALSE));
+  ASSERT (!IsNodeInList (ListHead, Entry));
   
   Entry->ForwardLink = ListHead->ForwardLink;
   Entry->BackLink = ListHead;
@@ -283,7 +242,7 @@ InsertTailList (
   //
   // ASSERT List not too long and Entry is not one of the nodes of List
   //
-  ASSERT (InternalBaseLibIsNodeInList (ListHead, Entry, FALSE));
+  ASSERT (!IsNodeInList (ListHead, Entry));
   
   Entry->ForwardLink = ListHead;
   Entry->BackLink = ListHead->BackLink;
@@ -321,7 +280,7 @@ GetFirstNode (
   //
   // ASSERT List not too long
   //
-  ASSERT (InternalBaseLibIsNodeInList (List, List, FALSE));
+  ASSERT (InternalBaseLibIsListValid (List));
 
   return List->ForwardLink;
 }
@@ -357,7 +316,7 @@ GetNextNode (
   //
   // ASSERT List not too long and Node is one of the nodes of List
   //
-  ASSERT (InternalBaseLibIsNodeInList (List, Node, TRUE));
+  ASSERT (IsNodeInList (List, Node));
 
   return Node->ForwardLink;
 }
@@ -393,7 +352,7 @@ GetPreviousNode (
   //
   // ASSERT List not too long and Node is one of the nodes of List
   //
-  ASSERT (InternalBaseLibIsNodeInList (List, Node, TRUE));
+  ASSERT (IsNodeInList (List, Node));
  
   return Node->BackLink;
 }
@@ -426,7 +385,7 @@ IsListEmpty (
   //
   // ASSERT List not too long
   //
-  ASSERT (InternalBaseLibIsNodeInList (ListHead, ListHead, FALSE));
+  InternalBaseLibIsListValid (ListHead);
   
   return (BOOLEAN)(ListHead->ForwardLink == ListHead);
 }
@@ -467,7 +426,7 @@ IsNull (
   //
   // ASSERT List not too long and Node is one of the nodes of List
   //
-  ASSERT (InternalBaseLibIsNodeInList (List, Node, TRUE));
+  ASSERT (IsNodeInList (List, Node));
   
   return (BOOLEAN)(Node == List);
 }
@@ -505,7 +464,7 @@ IsNodeAtEnd (
   //
   // ASSERT List not too long and Node is one of the nodes of List
   //
-  ASSERT (InternalBaseLibIsNodeInList (List, Node, TRUE));
+  ASSERT (IsNodeInList (List, Node));
   
   return (BOOLEAN)(!IsNull (List, Node) && List->BackLink == Node);
 }
@@ -552,7 +511,7 @@ SwapListEntries (
   //
   // ASSERT Entry1 and Entry2 are in the same linked list
   //
-  ASSERT (InternalBaseLibIsNodeInList (FirstEntry, SecondEntry, TRUE));
+  ASSERT (IsNodeInList (FirstEntry, SecondEntry));
   
   //
   // Ptr is the node pointed to by FirstEntry->ForwardLink
-- 
2.12.2.windows.2