[PATCH V3] MdeModulePkg/DxeCore: Fixed Interface returned by CoreOpenProtocol

[Amit Kumar <amit.ak@samsung.com>]

Change Since v2:
1) Modified to use EFI_ERROR to get status code

Change since v1:
1) Fixed typo protocal to protocol
2) Fixed coding style

Modified source code to update Interface as per spec.
1) In case of Protocol is un-supported, interface should be returned NULL.
2) In case of any error, interface should not be modified.
3) In case of Test Protocol, interface is optional.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Amit Kumar <amit.ak@samsung.com>
---
 MdeModulePkg/Core/Dxe/Hand/Handle.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/MdeModulePkg/Core/Dxe/Hand/Handle.c b/MdeModulePkg/Core/Dxe/Hand/Handle.c
index 1c25521..6de300f 100644
--- a/MdeModulePkg/Core/Dxe/Hand/Handle.c
+++ b/MdeModulePkg/Core/Dxe/Hand/Handle.c
@@ -1004,12 +1004,8 @@ CoreOpenProtocol (
   //
   // Check for invalid Interface
   //
-  if (Attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL) {
-    if (Interface == NULL) {
-      return EFI_INVALID_PARAMETER;
-    } else {
-      *Interface = NULL;
-    }
+  if ((Attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL) && (Interface == NULL)) {
+    return EFI_INVALID_PARAMETER;
   }
 
   //
@@ -1073,15 +1069,11 @@ CoreOpenProtocol (
   Prot = CoreGetProtocolInterface (UserHandle, Protocol);
   if (Prot == NULL) {
     Status = EFI_UNSUPPORTED;
+    // Return NULL Interface if Unsupported Protocol
+    *Interface = NULL;
     goto Done;
   }
 
-  //
-  // This is the protocol interface entry for this protocol
-  //
-  if (Attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL) {
-    *Interface = Prot->Interface;
-  }
   Status = EFI_SUCCESS;
 
   ByDriver        = FALSE;
@@ -1175,6 +1167,14 @@ CoreOpenProtocol (
   }
 
 Done:
+
+  //
+  // This is the protocol interface entry for this protocol.
+  // In case of any Error, Interface should not be updated as per spec.
+  //
+  if (!EFI_ERROR (Status) && Attributes != EFI_OPEN_PROTOCOL_TEST_PROTOCOL) {
+    *Interface = Prot->Interface;
+  }
   //
   // Done. Release the database lock are return
   //
-- 
1.9.1