[edk2-devel] [PATCH v2 1/7] MdePkg/BaseLib: Add linked list iteration macros

[Michael Kubacki]

From: Michael Kubacki <michael.kubacki at microsoft.com>

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1959

The macros EFI_LIST_FOR_EACH and EFI_LIST_FOR_EACH_SAFE have been
duplicated across several drivers. These macros have proven useful and
established a commonly used pattern for linked list iteration.

This change defines the macros in BaseLib.h alongside other generic linked
list macros and functions.

Cc: Dandan Bi <dandan.bi at intel.com>
Cc: Hao A Wu <hao.a.wu at intel.com>
Cc: Jian J Wang <jian.j.wang at intel.com>
Cc: Liming Gao <liming.gao at intel.com>
Cc: Michael D Kinney <michael.d.kinney at intel.com>
Cc: Sean Brogan <sean.brogan at microsoft.com>
Signed-off-by: Michael Kubacki <michael.kubacki at microsoft.com>
Reviewed-by: Guomin Jiang <guomin.jiang at intel.com>
---
 MdePkg/Include/Library/BaseLib.h | 27 ++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/MdePkg/Include/Library/BaseLib.h b/MdePkg/Include/Library/BaseLib.h
index ecadff8b235e..d066f1be2495 100644
--- a/MdePkg/Include/Library/BaseLib.h
+++ b/MdePkg/Include/Library/BaseLib.h
@@ -4,6 +4,7 @@
 
 Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
 Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
+Copyright (c) Microsoft Corporation.<BR>
 SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -2972,6 +2973,32 @@ PathCleanUpDirectories(
 **/
 #define INITIALIZE_LIST_HEAD_VARIABLE(ListHead)  {&(ListHead), &(ListHead)}
 
+/**
+  Iterates over each node in a doubly linked list using each node's forward link.
+
+  @param  Entry     A pointer to a list node used as a loop cursor during iteration
+  @param  ListHead  The head node of the doubly linked list
+
+**/
+#define BASE_LIST_FOR_EACH(Entry, ListHead)    \
+  for(Entry = (ListHead)->ForwardLink; Entry != (ListHead); Entry = Entry->ForwardLink)
+
+/**
+  Iterates over each node in a doubly linked list using each node's forward link
+  with safety against node removal.
+
+  This macro uses NextEntry to temporarily store the next list node so the node
+  pointed to by Entry may be deleted in the current loop iteration step and
+  iteration can continue from the node pointed to by NextEntry.
+
+  @param  Entry     A pointer to a list node used as a loop cursor during iteration
+  @param  NextEntry A pointer to a list node used to temporarily store the next node
+  @param  ListHead  The head node of the doubly linked list
+
+**/
+#define BASE_LIST_FOR_EACH_SAFE(Entry, NextEntry, ListHead)            \
+  for(Entry = (ListHead)->ForwardLink, NextEntry = Entry->ForwardLink;\
+      Entry != (ListHead); Entry = NextEntry, NextEntry = Entry->ForwardLink)
 
 /**
   Checks whether FirstEntry and SecondEntry are part of the same doubly-linked
-- 
2.16.3.windows.1


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