[PATCH v2] MdeModulePkg/Library: Add HiiGetStringEx to UefiHiiLib for EDK2 Redfish

["Abner Chang" <abner.chang@hpe.com>]

Add HiiGetStringEx and leveraged by HiiGetString function to support
getting string with the best language in optionally. This avoids the
string in x-uefi language is misled to the language defined by
"PlatformLang" or the "Supported Languages". This change is introduced
to support x-uefi keyword language for configuring BIOS setting.

Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
Signed-off-by: Siyuan Fu <siyuan.fu@intel.com>
Signed-off-by: Fan Wang <fan.wang@intel.com>
Signed-off-by: Abner Chang <abner.chang@hpe.com>
Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Nickle Wang <nickle.wang@hpe.com>
---
 MdeModulePkg/Include/Library/HiiLib.h       | 41 +++++++++++-
 MdeModulePkg/Library/UefiHiiLib/HiiString.c | 73 ++++++++++++++++-----
 2 files changed, 96 insertions(+), 18 deletions(-)

diff --git a/MdeModulePkg/Include/Library/HiiLib.h b/MdeModulePkg/Include/Library/HiiLib.h
index c475cb74a1..66c654dcd3 100644
--- a/MdeModulePkg/Include/Library/HiiLib.h
+++ b/MdeModulePkg/Include/Library/HiiLib.h
@@ -1,7 +1,7 @@
 /** @file
   Public include file for the HII Library
 
-Copyright (c) 2007 - 2018, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2007 - 2021, Intel Corporation. All rights reserved.<BR>
 SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -152,8 +152,43 @@ HiiGetString (
   IN EFI_HII_HANDLE  HiiHandle,
   IN EFI_STRING_ID   StringId,
   IN CONST CHAR8     *Language  OPTIONAL
-  )
-;
+  );
+
+/**
+  Retrieves a string from a string package in a specific language.  If the language
+  is not specified, then a string from a string package in the current platform
+  language is retrieved.  If the string can not be retrieved using the specified
+  language or the current platform language, then the string is retrieved from
+  the string package in the first language the string package supports.  The
+  returned string is allocated using AllocatePool().  The caller is responsible
+  for freeing the allocated buffer using FreePool().
+
+  If HiiHandle is NULL, then ASSERT().
+  If StringId is 0, then ASSET.
+
+  @param[in]  HiiHandle         A handle that was previously registered in the HII Database.
+  @param[in]  StringId          The identifier of the string to retrieved from the string
+                                package associated with HiiHandle.
+  @param[in]  Language          The language of the string to retrieve.  If this parameter
+                                is NULL, then the current platform language is used.  The
+                                format of Language must follow the language format assumed
+                                the HII Database.
+  @param[in]  TryBestLanguage   If TRUE, try to get the best matching language from all
+                                supported languages.
+
+
+  @retval NULL   The string specified by StringId is not present in the string package.
+  @retval Other  The string was returned.
+
+**/
+EFI_STRING
+EFIAPI
+HiiGetStringEx (
+  IN EFI_HII_HANDLE  HiiHandle,
+  IN EFI_STRING_ID   StringId,
+  IN CONST CHAR8     *Language  OPTIONAL,
+  IN BOOLEAN         TryBestLanguage
+  );
 
 /**
   Retrieves a string from a string package named by GUID, in the specified language.
diff --git a/MdeModulePkg/Library/UefiHiiLib/HiiString.c b/MdeModulePkg/Library/UefiHiiLib/HiiString.c
index 95229f8a8c..f3c52ace56 100644
--- a/MdeModulePkg/Library/UefiHiiLib/HiiString.c
+++ b/MdeModulePkg/Library/UefiHiiLib/HiiString.c
@@ -1,7 +1,7 @@
 /** @file
   HII Library implementation that uses DXE protocols and services.
 
-  Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2006 - 2021, Intel Corporation. All rights reserved.<BR>
   SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -220,6 +220,44 @@ HiiGetString (
   IN EFI_STRING_ID   StringId,
   IN CONST CHAR8     *Language  OPTIONAL
   )
+{
+  return HiiGetStringEx (HiiHandle, StringId, Language, TRUE);
+}
+
+/**
+  Retrieves a string from a string package in a specific language.  If the language
+  is not specified, then a string from a string package in the current platform
+  language is retrieved.  If the string can not be retrieved using the specified
+  language or the current platform language, then the string is retrieved from
+  the string package in the first language the string package supports.  The
+  returned string is allocated using AllocatePool().  The caller is responsible
+  for freeing the allocated buffer using FreePool().
+
+  If HiiHandle is NULL, then ASSERT().
+  If StringId is 0, then ASSET.
+
+  @param[in]  HiiHandle         A handle that was previously registered in the HII Database.
+  @param[in]  StringId          The identifier of the string to retrieved from the string
+                                package associated with HiiHandle.
+  @param[in]  Language          The language of the string to retrieve.  If this parameter
+                                is NULL, then the current platform language is used.  The
+                                format of Language must follow the language format assumed
+                                the HII Database.
+  @param[in]  TryBestLanguage   If TRUE, try to get the best matching language from all
+                                supported languages.
+
+  @retval NULL   The string specified by StringId is not present in the string package.
+  @retval Other  The string was returned.
+
+**/
+EFI_STRING
+EFIAPI
+HiiGetStringEx (
+  IN EFI_HII_HANDLE  HiiHandle,
+  IN EFI_STRING_ID   StringId,
+  IN CONST CHAR8     *Language  OPTIONAL,
+  IN BOOLEAN         TryBestLanguage
+  )
 {
   EFI_STATUS  Status;
   UINTN       StringSize;
@@ -261,21 +299,26 @@ HiiGetString (
     Language = "";
   }
 
-  //
-  // Get the best matching language from SupportedLanguages
-  //
-  BestLanguage = GetBestLanguage (
-                   SupportedLanguages,
-                   FALSE,                                             // RFC 4646 mode
-                   Language,                                          // Highest priority
-                   PlatformLanguage != NULL ? PlatformLanguage : "",  // Next highest priority
-                   SupportedLanguages,                                // Lowest priority
-                   NULL
-                   );
-  if (BestLanguage == NULL) {
-    goto Error;
+  if (TryBestLanguage) {
+    //
+    // Get the best matching language from SupportedLanguages
+    //
+    BestLanguage = GetBestLanguage (
+                     SupportedLanguages,
+                     FALSE,                                             // RFC 4646 mode
+                     Language,                                          // Highest priority
+                     PlatformLanguage != NULL ? PlatformLanguage : "",  // Next highest priority
+                     SupportedLanguages,                                // Lowest priority
+                     NULL
+                     );
+    if (BestLanguage == NULL) {
+      goto Error;
+    }
+  } else {
+    BestLanguage = (CHAR8 *) Language;
   }
 
+
   //
   // Retrieve the size of the string in the string package for the BestLanguage
   //
@@ -337,7 +380,7 @@ Error:
   if (PlatformLanguage != NULL) {
     FreePool (PlatformLanguage);
   }
-  if (BestLanguage != NULL) {
+  if (TryBestLanguage && BestLanguage != NULL) {
     FreePool (BestLanguage);
   }
 
-- 
2.17.1