From 8c7bc280bfae00561ef35bde14597ee372d24d17 Mon Sep 17 00:00:00 2001
From: Download-Fritz <download-fritz@outlook.com>
Date: Mon, 15 Jul 2019 09:16:53 +0200
Subject: [PATCH] OcDevicePathLib: Add deduplicate DP instance append API

---
 Include/Library/OcDevicePathLib.h         |  6 +++
 Library/OcDevicePathLib/OcDevicePathLib.c | 45 +++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/Include/Library/OcDevicePathLib.h b/Include/Library/OcDevicePathLib.h
index 956d0447..3d0a1c78 100755
--- a/Include/Library/OcDevicePathLib.h
+++ b/Include/Library/OcDevicePathLib.h
@@ -157,6 +157,12 @@ OcFileDevicePathNameLen (
   IN CONST FILEPATH_DEVICE_PATH  *FilePath
   );
 
+EFI_DEVICE_PATH_PROTOCOL *
+OcAppendDevicePathInstanceDedupe (
+  IN EFI_DEVICE_PATH_PROTOCOL        *DevicePath OPTIONAL,
+  IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathInstance OPTIONAL
+  );
+
 /**
   Fix Apple Boot Device Path to be compatible with conventional UEFI
   implementations.
diff --git a/Library/OcDevicePathLib/OcDevicePathLib.c b/Library/OcDevicePathLib/OcDevicePathLib.c
index f6122a0c..3a9ec4d5 100755
--- a/Library/OcDevicePathLib/OcDevicePathLib.c
+++ b/Library/OcDevicePathLib/OcDevicePathLib.c
@@ -735,3 +735,48 @@ OcFileDevicePathNameLen (
 
   return Len;
 }
+
+EFI_DEVICE_PATH_PROTOCOL *
+OcAppendDevicePathInstanceDedupe (
+  IN EFI_DEVICE_PATH_PROTOCOL        *DevicePath OPTIONAL,
+  IN CONST EFI_DEVICE_PATH_PROTOCOL  *DevicePathInstance OPTIONAL
+  )
+{
+  INTN                           CmpResult;
+
+  EFI_DEVICE_PATH_PROTOCOL       *DevPathWalker;
+  CONST EFI_DEVICE_PATH_PROTOCOL *CurrentInstance;
+
+  UINTN                          AppendInstanceSize;
+  UINTN                          CurrentInstanceSize;
+
+  if (DevicePath != NULL && DevicePathInstance != NULL) {
+    AppendInstanceSize = GetDevicePathSize (DevicePathInstance);
+    DevPathWalker = DevicePath;
+
+    while (TRUE) {
+      CurrentInstance = GetNextDevicePathInstance (
+                          &DevPathWalker,
+                          &CurrentInstanceSize
+                          );
+      if (CurrentInstance == NULL) {
+        break;
+      }
+
+      if (CurrentInstanceSize != AppendInstanceSize) {
+        continue;
+      }
+
+      CmpResult = CompareMem (
+                    CurrentInstance,
+                    DevicePathInstance,
+                    CurrentInstanceSize
+                    );
+      if (CmpResult == 0) {
+        return DuplicateDevicePath (DevicePath);
+      }
+    }
+  }
+
+  return AppendDevicePathInstance (DevicePath, DevicePathInstance);
+}