Re: [RestJsonStructureDxe PATCH v3 2/3] RedfishPkg/RestJsonStructureDxe: EFI REST JSON Structure Protocol

["Nickle Wang" <nickle.wang@hpe.com>]

Hi Abner,

I have comment for function RestJsonStructureUnload(). Please check my inline comment below.

Thanks,
Nickle

> -----Original Message-----
> From: Chang, Abner (HPS SW/FW Technologist) <abner.chang@hpe.com>
> Sent: Thursday, October 15, 2020 11:49 PM
> To: devel@edk2.groups.io
> Cc: Jiaxin Wu <jiaxin.wu@intel.com>; Siyuan Fu <siyuan.fu@intel.com>; Fan
> Wang <fan.wang@intel.com>; Jiewen Yao <jiewen.yao@intel.com>; Wang,
> Nickle (HPS SW) <nickle.wang@hpe.com>
> Subject: [RestJsonStructureDxe PATCH v3 2/3]
> RedfishPkg/RestJsonStructureDxe: EFI REST JSON Structure Protocol
> 
> Implementation of EFI_REST_JSON_STRUCTURE_PROTOCOL, refer to UEFI
> spec
> 2.8 Section 29.7.3 EFI REST JSON Resource to C Structure Converter.
> 
> Signed-off-by: Abner Chang <abner.chang@hpe.com>
> 
> Cc: Jiaxin Wu <jiaxin.wu@intel.com>
> Cc: Siyuan Fu <siyuan.fu@intel.com>
> Cc: Fan Wang <fan.wang@intel.com>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Nickle Wang <nickle.wang@hpe.com>
> ---
>  RedfishPkg/RedfishPkg.dsc                     |  11 +
>  .../RestJsonStructureDxe.c                    | 585 ++++++++++++++++++
>  .../RestJsonStructureDxe.inf                  |  40 ++
>  .../RestJsonStructureInternal.h               |  33 +
>  4 files changed, 669 insertions(+)
>  create mode 100644
> RedfishPkg/RestJsonStructureDxe/RestJsonStructureDxe.c
>  create mode 100644
> RedfishPkg/RestJsonStructureDxe/RestJsonStructureDxe.inf
>  create mode 100644
> RedfishPkg/RestJsonStructureDxe/RestJsonStructureInternal.h
> 
> diff --git a/RedfishPkg/RedfishPkg.dsc b/RedfishPkg/RedfishPkg.dsc
> index 8acadddefc..f0c6740fac 100644
> --- a/RedfishPkg/RedfishPkg.dsc
> +++ b/RedfishPkg/RedfishPkg.dsc
> @@ -38,3 +38,14 @@
> 
> DxeServicesTableLib|MdePkg/Library/DxeServicesTableLib/DxeServicesTabl
> eLib.inf
>    DxeServicesLib|MdePkg/Library/DxeServicesLib/DxeServicesLib.inf
> 
> ReportStatusCodeLib|MdeModulePkg/Library/DxeReportStatusCodeLib/Dx
> eReportStatusCodeLib.inf
> +
> +[LibraryClasses.ARM, LibraryClasses.AARCH64]
> +  #
> +  # This library provides the instrinsic functions generated by a given
> compiler.
> +  #
> +  NULL|ArmPkg/Library/CompilerIntrinsicsLib/CompilerIntrinsicsLib.inf
> +  NULL|MdePkg/Library/BaseStackCheckLib/BaseStackCheckLib.inf
> +  ArmSoftFloatLib|ArmPkg/Library/ArmSoftFloatLib/ArmSoftFloatLib.inf
> +
> +[Components]
> +  RedfishPkg/RestJsonStructureDxe/RestJsonStructureDxe.inf
> diff --git a/RedfishPkg/RestJsonStructureDxe/RestJsonStructureDxe.c
> b/RedfishPkg/RestJsonStructureDxe/RestJsonStructureDxe.c
> new file mode 100644
> index 0000000000..03fbecf993
> --- /dev/null
> +++ b/RedfishPkg/RestJsonStructureDxe/RestJsonStructureDxe.c
> @@ -0,0 +1,585 @@
> +/** @file
> +
> +  The implementation of EFI REST Resource JSON to C structure convertor
> +  Protocol.
> +
> +  (C) Copyright 2020 Hewlett Packard Enterprise Development LP<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#include <Uefi.h>
> +#include <Protocol/RestJsonStructure.h>
> +#include "RestJsonStructureInternal.h"
> +
> +LIST_ENTRY mRestJsonStructureList;
> +EFI_HANDLE mProtocolHandle;
> +
> +/**
> +  This function registers Restful resource interpreter for the
> +  specific schema.
> +
> +  @param[in]    This                     This is the
> EFI_REST_JSON_STRUCTURE_PROTOCOL instance.
> +  @param[in]    JsonStructureSupported   The type and version of REST JSON
> resource which this converter
> +                                         supports.
> +  @param[in]    ToStructure              The function to convert REST JSON
> resource to structure.
> +  @param[in]    ToJson                   The function to convert REST JSON structure
> to JSON in text format.
> +  @param[in]    DestroyStructure         Destroy REST JSON structure returned
> in ToStructure()  function.
> +
> +  @retval EFI_SUCCESS             Register successfully.
> +  @retval Others                  Fail to register.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +RestJsonStructureRegister (
> +  IN EFI_REST_JSON_STRUCTURE_PROTOCOL       *This,
> +  IN EFI_REST_JSON_STRUCTURE_SUPPORTED      *JsonStructureSupported,
> +  IN EFI_REST_JSON_STRUCTURE_TO_STRUCTURE   ToStructure,
> +  IN EFI_REST_JSON_STRUCTURE_TO_JSON        ToJson,
> +  IN EFI_REST_JSON_STRUCTURE_DESTORY_STRUCTURE DestroyStructure
> +)
> +{
> +  UINTN NumberOfNS;
> +  UINTN Index;
> +  LIST_ENTRY *ThisList;
> +  REST_JSON_STRUCTURE_INSTANCE *Instance;
> +  EFI_REST_JSON_RESOURCE_TYPE_IDENTIFIER *CloneSupportedInterpId;
> +  EFI_REST_JSON_STRUCTURE_SUPPORTED *ThisSupportedInterp;
> +
> +  if (This == NULL ||
> +      ToStructure == NULL ||
> +      ToJson == NULL ||
> +      DestroyStructure == NULL ||
> +      JsonStructureSupported == NULL
> +      ) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // Check how many name space interpreter can interpret.
> +  //
> +  ThisList = &JsonStructureSupported->NextSupportedRsrcInterp;
> +  NumberOfNS = 1;
> +  while (TRUE) {
> +    if (ThisList->ForwardLink == &JsonStructureSupported-
> >NextSupportedRsrcInterp) {
> +      break;
> +    } else {
> +      ThisList = ThisList->ForwardLink;
> +      NumberOfNS ++;
> +    }
> +  };
> +
> +  Instance =
> +    (REST_JSON_STRUCTURE_INSTANCE *)AllocateZeroPool (sizeof
> (REST_JSON_STRUCTURE_INSTANCE) + NumberOfNS * sizeof
> (EFI_REST_JSON_RESOURCE_TYPE_IDENTIFIER));
> +  if (Instance == NULL) {
> +    return EFI_OUT_OF_RESOURCES;
> +  }
> +  InitializeListHead (&Instance->NextRestJsonStructureInstance);
> +  Instance->NumberOfNameSpaceToConvert = NumberOfNS;
> +  Instance->SupportedRsrcIndentifier =
> (EFI_REST_JSON_RESOURCE_TYPE_IDENTIFIER
> *)((REST_JSON_STRUCTURE_INSTANCE *)Instance + 1);
> +  //
> +  // Copy supported resource identifer interpreter.
> +  //
> +  CloneSupportedInterpId = Instance->SupportedRsrcIndentifier;
> +  ThisSupportedInterp = JsonStructureSupported;
> +  for (Index = 0; Index < NumberOfNS; Index ++) {
> +    CopyMem ((VOID *)CloneSupportedInterpId, (VOID
> *)&ThisSupportedInterp->RestResourceInterp, sizeof
> (EFI_REST_JSON_RESOURCE_TYPE_IDENTIFIER));
> +    ThisSupportedInterp = (EFI_REST_JSON_STRUCTURE_SUPPORTED
> *)ThisSupportedInterp->NextSupportedRsrcInterp.ForwardLink;
> +    CloneSupportedInterpId ++;
> +  }
> +  Instance->JsonToStructure = ToStructure;
> +  Instance->StructureToJson = ToJson;
> +  Instance->DestroyStructure = DestroyStructure;
> +  InsertTailList (&mRestJsonStructureList, &Instance-
> >NextRestJsonStructureInstance);
> +  return EFI_SUCCESS;
> +}
> +
> +/**
> +  This function check if this interpreter instance support the given
> namesapce.
> +
> +  @param[in]    This                EFI_REST_JSON_STRUCTURE_PROTOCOL
> instance.
> +  @param[in]    InterpreterInstance REST_JSON_STRUCTURE_INSTANCE
> +  @param[in]    RsrcTypeIdentifier  Resource type identifier.
> +  @param[in]    ResourceRaw         Given Restful resource.
> +  @param[out]   RestJSonHeader      Property interpreted from given
> ResourceRaw.
> +
> +  @retval EFI_SUCCESS
> +  @retval Others.
> +
> +**/
> +EFI_STATUS
> +InterpreterInstanceToStruct (
> +  IN EFI_REST_JSON_STRUCTURE_PROTOCOL         *This,
> +  IN REST_JSON_STRUCTURE_INSTANCE             *InterpreterInstance,
> +  IN EFI_REST_JSON_RESOURCE_TYPE_IDENTIFIER   *RsrcTypeIdentifier
> OPTIONAL,
> +  IN CHAR8                                    *ResourceRaw,
> +  OUT EFI_REST_JSON_STRUCTURE_HEADER          **RestJSonHeader
> + )
> +{
> +  UINTN Index;
> +  EFI_STATUS Status;
> +  EFI_REST_JSON_RESOURCE_TYPE_IDENTIFIER *ThisSupportedRsrcTypeId;
> +
> +  if (This == NULL ||
> +      InterpreterInstance == NULL ||
> +      ResourceRaw == NULL ||
> +      RestJSonHeader == NULL
> +      ) {
> +      return EFI_INVALID_PARAMETER;
> +  }
> +
> +  Status = EFI_UNSUPPORTED;
> +  if (RsrcTypeIdentifier == NULL) {
> +    //
> +    // No resource type identifier, send to intepreter anyway.
> +    // Interpreter may recognize this resource.
> +    //
> +    Status = InterpreterInstance->JsonToStructure (
> +                This,
> +                NULL,
> +                ResourceRaw,
> +                RestJSonHeader
> +                );
> +  } else {
> +    //
> +    // Check if the namesapce and version is supported by this interpreter.
> +    //
> +    ThisSupportedRsrcTypeId = InterpreterInstance-
> >SupportedRsrcIndentifier;
> +    for (Index = 0; Index < InterpreterInstance-
> >NumberOfNameSpaceToConvert; Index ++){
> +      if (AsciiStrCmp (
> +            RsrcTypeIdentifier->NameSpace.ResourceTypeName,
> +            ThisSupportedRsrcTypeId->NameSpace.ResourceTypeName) == 0){
> +        if ((RsrcTypeIdentifier->NameSpace.MajorVersion == NULL) &&
> +            (RsrcTypeIdentifier->NameSpace.MinorVersion == NULL) &&
> +            (RsrcTypeIdentifier->NameSpace.ErrataVersion == NULL)
> +            ) {
> +          //
> +          // Don't check version of this resource type identifier.
> +          //
> +          Status = InterpreterInstance->JsonToStructure (
> +                      This,
> +                      RsrcTypeIdentifier,
> +                      ResourceRaw,
> +                      RestJSonHeader
> +                      );
> +          break;
> +        } else {
> +          //
> +          // Check version.
> +          //
> +          if ((AsciiStrCmp (
> +                RsrcTypeIdentifier->NameSpace.MajorVersion,
> +                ThisSupportedRsrcTypeId->NameSpace.MajorVersion) == 0) &&
> +              (AsciiStrCmp (
> +                RsrcTypeIdentifier->NameSpace.MinorVersion,
> +                ThisSupportedRsrcTypeId->NameSpace.MinorVersion) == 0) &&
> +              (AsciiStrCmp (
> +                RsrcTypeIdentifier->NameSpace.ErrataVersion,
> +                ThisSupportedRsrcTypeId->NameSpace.ErrataVersion) == 0)) {
> +            Status = InterpreterInstance->JsonToStructure (
> +                      This,
> +                      RsrcTypeIdentifier,
> +                      ResourceRaw,
> +                      RestJSonHeader
> +                      );
> +            break;
> +          }
> +        }
> +      }
> +      ThisSupportedRsrcTypeId ++;
> +    }
> +  }
> +  return Status;
> +}
> +/**
> +  This function converts JSON C structure to JSON property.
> +
> +  @param[in]    This                 EFI_REST_JSON_STRUCTURE_PROTOCOL
> instance.
> +  @param[in]    InterpreterInstance  REST_JSON_STRUCTURE_INSTANCE
> +  @param[in]    RestJSonHeader       Resource type identifier.
> +  @param[out]   ResourceRaw          Output in JSON text format.
> +
> +  @retval EFI_SUCCESS
> +  @retval Others.
> +
> +**/
> +EFI_STATUS
> +InterpreterEfiStructToInstance (
> +  IN EFI_REST_JSON_STRUCTURE_PROTOCOL   *This,
> +  IN REST_JSON_STRUCTURE_INSTANCE       *InterpreterInstance,
> +  IN EFI_REST_JSON_STRUCTURE_HEADER     *RestJSonHeader,
> +  OUT CHAR8 **ResourceRaw
> +)
> +{
> +  UINTN Index;
> +  EFI_STATUS Status;
> +  EFI_REST_JSON_RESOURCE_TYPE_IDENTIFIER *ThisSupportedRsrcTypeId;
> +  EFI_REST_JSON_RESOURCE_TYPE_IDENTIFIER *RsrcTypeIdentifier;
> +
> +  if (This == NULL ||
> +      InterpreterInstance == NULL ||
> +      RestJSonHeader == NULL ||
> +      ResourceRaw == NULL
> +      ) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +  RsrcTypeIdentifier = &RestJSonHeader->JsonRsrcIdentifier;
> +  if (RsrcTypeIdentifier == NULL ||
> +      RsrcTypeIdentifier->NameSpace.ResourceTypeName == NULL ||
> +      RsrcTypeIdentifier->NameSpace.MajorVersion == NULL ||
> +      RsrcTypeIdentifier->NameSpace.MinorVersion == NULL ||
> +      RsrcTypeIdentifier->NameSpace.ErrataVersion == NULL
> +      ) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  //
> +  // Check if the namesapce and version is supported by this interpreter.
> +  //
> +  Status = EFI_UNSUPPORTED;
> +  ThisSupportedRsrcTypeId = InterpreterInstance-
> >SupportedRsrcIndentifier;
> +  for (Index = 0; Index < InterpreterInstance-
> >NumberOfNameSpaceToConvert; Index ++){
> +    if (AsciiStrCmp (
> +          RsrcTypeIdentifier->NameSpace.ResourceTypeName,
> +          ThisSupportedRsrcTypeId->NameSpace.ResourceTypeName) == 0){
> +      //
> +      // Check version.
> +      //
> +      if ((AsciiStrCmp (
> +            RsrcTypeIdentifier->NameSpace.MajorVersion,
> +            ThisSupportedRsrcTypeId->NameSpace.MajorVersion) == 0) &&
> +          (AsciiStrCmp (
> +            RsrcTypeIdentifier->NameSpace.MinorVersion,
> +            ThisSupportedRsrcTypeId->NameSpace.MinorVersion) == 0) &&
> +          (AsciiStrCmp (
> +            RsrcTypeIdentifier->NameSpace.ErrataVersion,
> +            ThisSupportedRsrcTypeId->NameSpace.ErrataVersion) == 0)) {
> +        Status = InterpreterInstance->StructureToJson (
> +                  This,
> +                  RestJSonHeader,
> +                  ResourceRaw
> +                  );
> +        break;
> +      }
> +    }
> +    ThisSupportedRsrcTypeId ++;
> +  }
> +  return Status;
> +}
> +
> +/**
> +  This function destory REST property structure.
> +
> +  @param[in]    This                 EFI_REST_JSON_STRUCTURE_PROTOCOL
> instance.
> +  @param[in]    InterpreterInstance  REST_JSON_STRUCTURE_INSTANCE
> +  @param[in]    RestJSonHeader       Property interpreted from given
> ResourceRaw.
> +
> +  @retval EFI_SUCCESS
> +  @retval Others.
> +
> +**/
> +EFI_STATUS
> +InterpreterInstanceDestoryJsonStruct (
> +  IN EFI_REST_JSON_STRUCTURE_PROTOCOL       *This,
> +  IN REST_JSON_STRUCTURE_INSTANCE           *InterpreterInstance,
> +  IN EFI_REST_JSON_STRUCTURE_HEADER         *RestJSonHeader
> + )
> +{
> +  UINTN Index;
> +  EFI_STATUS Status;
> +  EFI_REST_JSON_RESOURCE_TYPE_IDENTIFIER *ThisSupportedRsrcTypeId;
> +
> +  if (This == NULL ||
> +      InterpreterInstance == NULL ||
> +      RestJSonHeader == NULL
> +      ) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  Status = EFI_UNSUPPORTED;
> +  //
> +  // Check if the namesapce and version is supported by this interpreter.
> +  //
> +  ThisSupportedRsrcTypeId = InterpreterInstance-
> >SupportedRsrcIndentifier;
> +  for (Index = 0; Index < InterpreterInstance-
> >NumberOfNameSpaceToConvert; Index ++){
> +    if (AsciiStrCmp (
> +          RestJSonHeader->JsonRsrcIdentifier.NameSpace.ResourceTypeName,
> +          ThisSupportedRsrcTypeId->NameSpace.ResourceTypeName) == 0) {
> +      if ((RestJSonHeader->JsonRsrcIdentifier.NameSpace.MajorVersion ==
> NULL) &&
> +          (RestJSonHeader->JsonRsrcIdentifier.NameSpace.MinorVersion ==
> NULL) &&
> +          (RestJSonHeader->JsonRsrcIdentifier.NameSpace.ErrataVersion ==
> NULL)
> +          ) {
> +        //
> +        // Don't check version of this resource type identifier.
> +        //
> +        Status = InterpreterInstance->DestroyStructure (
> +                    This,
> +                    RestJSonHeader
> +                    );
> +        break;
> +      } else {
> +        //
> +        // Check version.
> +        //
> +        if ((AsciiStrCmp (
> +              RestJSonHeader->JsonRsrcIdentifier.NameSpace.MajorVersion,
> +              ThisSupportedRsrcTypeId->NameSpace.MajorVersion) == 0) &&
> +            (AsciiStrCmp (
> +              RestJSonHeader->JsonRsrcIdentifier.NameSpace.MinorVersion,
> +              ThisSupportedRsrcTypeId->NameSpace.MinorVersion) == 0) &&
> +            (AsciiStrCmp (
> +              RestJSonHeader->JsonRsrcIdentifier.NameSpace.ErrataVersion,
> +              ThisSupportedRsrcTypeId->NameSpace.ErrataVersion) == 0)) {
> +          Status = InterpreterInstance->DestroyStructure (
> +                    This,
> +                    RestJSonHeader
> +                    );
> +          break;
> +        }
> +      }
> +    }
> +    ThisSupportedRsrcTypeId ++;
> +  }
> +  return Status;
> +}
> +
> +/**
> +  This function translates the given JSON text to JSON C Structure.
> +
> +  @param[in]    This                EFI_REST_JSON_STRUCTURE_PROTOCOL
> instance.
> +  @param[in]    RsrcTypeIdentifier  Resource type identifier.
> +  @param[in]    ResourceJsonText    Given Restful resource.
> +  @param[out]   JsonStructure       Property interpreted from given
> ResourceRaw.
> +
> +  @retval EFI_SUCCESS
> +  @retval Others.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +RestJsonStructureToStruct (
> +  IN EFI_REST_JSON_STRUCTURE_PROTOCOL       *This,
> +  IN EFI_REST_JSON_RESOURCE_TYPE_IDENTIFIER *RsrcTypeIdentifier
> OPTIONAL,
> +  IN CHAR8                                  *ResourceJsonText,
> +  OUT EFI_REST_JSON_STRUCTURE_HEADER        **JsonStructure
> +)
> +{
> +  EFI_STATUS Status;
> +  REST_JSON_STRUCTURE_INSTANCE *Instance;
> +
> +  if (This == NULL ||
> +      ResourceJsonText == NULL ||
> +      JsonStructure == NULL
> +    ) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (IsListEmpty (&mRestJsonStructureList)) {
> +    return EFI_UNSUPPORTED;
> +  }
> +  Status = EFI_SUCCESS;
> +  Instance = (REST_JSON_STRUCTURE_INSTANCE *)GetFirstNode
> (&mRestJsonStructureList);
> +  while (TRUE) {
> +    Status = InterpreterInstanceToStruct (
> +                This,
> +                Instance,
> +                RsrcTypeIdentifier,
> +                ResourceJsonText,
> +                JsonStructure
> +              );
> +    if (!EFI_ERROR (Status)) {
> +      break;
> +    }
> +    if (IsNodeAtEnd(&mRestJsonStructureList, &Instance-
> >NextRestJsonStructureInstance)) {
> +      Status = EFI_UNSUPPORTED;
> +      break;
> +    }
> +    Instance = (REST_JSON_STRUCTURE_INSTANCE *)GetNextNode
> (&mRestJsonStructureList, &Instance->NextRestJsonStructureInstance);
> +  };
> +  return Status;
> +}
> +
> +/**
> +  This function destory REST property EFI structure which returned in
> +  JsonToStructure().
> +
> +  @param[in]    This            EFI_REST_JSON_STRUCTURE_PROTOCOL instance.
> +  @param[in]    RestJSonHeader  Property to destory.
> +
> +  @retval EFI_SUCCESS
> +  @retval Others
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +RestJsonStructureDestroyStruct (
> +  IN EFI_REST_JSON_STRUCTURE_PROTOCOL *This,
> +  IN EFI_REST_JSON_STRUCTURE_HEADER  *RestJSonHeader
> +)
> +{
> +  EFI_STATUS Status;
> +  REST_JSON_STRUCTURE_INSTANCE *Instance;
> +
> +  if (This == NULL || RestJSonHeader == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (IsListEmpty (&mRestJsonStructureList)) {
> +    return EFI_UNSUPPORTED;
> +  }
> +  Status = EFI_SUCCESS;
> +  Instance = (REST_JSON_STRUCTURE_INSTANCE *)GetFirstNode
> (&mRestJsonStructureList);
> +  while (TRUE) {
> +    Status = InterpreterInstanceDestoryJsonStruct (
> +                This,
> +                Instance,
> +                RestJSonHeader
> +              );
> +    if (!EFI_ERROR (Status)) {
> +      break;
> +    }
> +    if (IsNodeAtEnd(&mRestJsonStructureList, &Instance-
> >NextRestJsonStructureInstance)) {
> +      Status = EFI_UNSUPPORTED;
> +      break;
> +    }
> +    Instance = (REST_JSON_STRUCTURE_INSTANCE *)GetNextNode
> (&mRestJsonStructureList, &Instance->NextRestJsonStructureInstance);
> +  };
> +  return Status;
> +}
> +
> +/**
> +  This function translates the given JSON C Structure to JSON text.
> +
> +  @param[in]    This            EFI_REST_JSON_STRUCTURE_PROTOCOL instance.
> +  @param[in]    RestJSonHeader  Given Restful resource.
> +  @param[out]   ResourceRaw     Resource in RESTfuls service oriented.
> +
> +  @retval EFI_SUCCESS
> +  @retval Others             Fail to remove the entry
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +RestJsonStructureToJson (
> +  IN EFI_REST_JSON_STRUCTURE_PROTOCOL *This,
> +  IN EFI_REST_JSON_STRUCTURE_HEADER *RestJSonHeader,
> +  OUT CHAR8 **ResourceRaw
> +)
> +{
> +  EFI_STATUS Status;
> +  REST_JSON_STRUCTURE_INSTANCE *Instance;
> +
> +  if (This == NULL || RestJSonHeader == NULL || ResourceRaw == NULL) {
> +    return EFI_INVALID_PARAMETER;
> +  }
> +
> +  if (IsListEmpty (&mRestJsonStructureList)) {
> +    return EFI_UNSUPPORTED;
> +  }
> +  Status = EFI_SUCCESS;
> +  Instance = (REST_JSON_STRUCTURE_INSTANCE *)GetFirstNode
> (&mRestJsonStructureList);
> +  while (TRUE) {
> +    Status = InterpreterEfiStructToInstance (
> +                This,
> +                Instance,
> +                RestJSonHeader,
> +                ResourceRaw
> +              );
> +    if (!EFI_ERROR (Status)) {
> +      break;
> +    }
> +    if (IsNodeAtEnd(&mRestJsonStructureList, &Instance-
> >NextRestJsonStructureInstance)) {
> +      Status = EFI_UNSUPPORTED;
> +      break;
> +    }
> +    Instance = (REST_JSON_STRUCTURE_INSTANCE *)GetNextNode
> (&mRestJsonStructureList, &Instance->NextRestJsonStructureInstance);
> +  };
> +  return Status;
> +}
> +
> +EFI_REST_JSON_STRUCTURE_PROTOCOL mRestJsonStructureProtocol = {
> +  RestJsonStructureRegister,
> +  RestJsonStructureToStruct,
> +  RestJsonStructureToJson,
> +  RestJsonStructureDestroyStruct
> +};
> +
> +/**
> +  This is the declaration of an EFI image entry point.
> +
> +  @param  ImageHandle           The firmware allocated handle for the UEFI
> image.
> +  @param  SystemTable           A pointer to the EFI System Table.
> +
> +  @retval EFI_SUCCESS           The operation completed successfully.
> +  @retval Others                An unexpected error occurred.
> +**/
> +EFI_STATUS
> +EFIAPI
> +RestJsonStructureEntryPoint (
> +  IN EFI_HANDLE        ImageHandle,
> +  IN EFI_SYSTEM_TABLE  *SystemTable
> +  )
> +{
> +  EFI_STATUS Status;
> +
> +  InitializeListHead (&mRestJsonStructureList);
> +  //
> +  // Install the Restful Resource Interpreter Protocol.
> +  //
> +  mProtocolHandle = NULL;
> +  Status = gBS->InstallProtocolInterface (
> +                  &mProtocolHandle,
> +                  &gEfiRestJsonStructureProtocolGuid,
> +                  EFI_NATIVE_INTERFACE,
> +                  (VOID *)&mRestJsonStructureProtocol
> +                  );
> +  return Status;
> +}
> +
> +/**
> +  This is the unload handle for Redfish discover module.
> +
> +  Disconnect the driver specified by ImageHandle from all the devices in the
> handle database.
> +  Uninstall all the protocols installed in the driver entry point.
> +
> +  @param[in] ImageHandle           The drivers' driver image.
> +
> +  @retval    EFI_SUCCESS           The image is unloaded.
> +  @retval    Others                Failed to unload the image.
> +
> +**/
> +EFI_STATUS
> +EFIAPI
> +RestJsonStructureUnload (
> +  IN EFI_HANDLE ImageHandle
> +  )
> +{
> +  EFI_STATUS Status;
> +  REST_JSON_STRUCTURE_INSTANCE *Instance;
> +  REST_JSON_STRUCTURE_INSTANCE *NextInstance;
> +
> +  if (IsListEmpty (&mRestJsonStructureList)) {
> +    return EFI_SUCCESS;
> +  }
We still need to uninstall REST Json Structure Protocol when list is empty, right? The protocol is installed on driver entry when list is empty. 

> +  //
> +  // Free memory of REST_JSON_STRUCTURE_INSTANCE instance.
> +  //
> +  Instance = (REST_JSON_STRUCTURE_INSTANCE *)GetFirstNode
> (&mRestJsonStructureList);
> +  do {
> +    NextInstance = NULL;
> +    if (!IsNodeAtEnd(&mRestJsonStructureList, &Instance-
> >NextRestJsonStructureInstance)) {
> +      NextInstance = (REST_JSON_STRUCTURE_INSTANCE *)GetNextNode
> (&mRestJsonStructureList, &Instance->NextRestJsonStructureInstance);
> +    }
> +    FreePool ((VOID *)Instance);
> +    Instance = NextInstance;
> +  } while (Instance != NULL);
> +
> +  Status = gBS->UninstallProtocolInterface (
> +                  mProtocolHandle,
> +                  &gEfiRestJsonStructureProtocolGuid,
> +                  (VOID *)&mRestJsonStructureProtocol
> +                  );
> +  return Status;
> +}
> diff --git a/RedfishPkg/RestJsonStructureDxe/RestJsonStructureDxe.inf
> b/RedfishPkg/RestJsonStructureDxe/RestJsonStructureDxe.inf
> new file mode 100644
> index 0000000000..2ab1e3bc45
> --- /dev/null
> +++ b/RedfishPkg/RestJsonStructureDxe/RestJsonStructureDxe.inf
> @@ -0,0 +1,40 @@
> +## @file
> +# Implementation of EFI REST JSON Structure Protocol.
> +#
> +#  (C) Copyright 2020 Hewlett Packard Enterprise Development LP<BR>
> +#  SPDX-License-Identifier: BSD-2-Clause-Patent
> +#
> +##
> +
> +[Defines]
> +  INF_VERSION               = 0x00010005
> +  BASE_NAME                 = RestJsonStructureDxe
> +  FILE_GUID                 = 83FAAFBF-FC4B-469F-892A-798E66A6F50A
> +  MODULE_TYPE               = DXE_DRIVER
> +  VERSION_STRING            = 1.0
> +  ENTRY_POINT               = RestJsonStructureEntryPoint
> +  UNLOAD_IMAGE              = RestJsonStructureUnload
> +
> +[Packages]
> +  MdePkg/MdePkg.dec
> +  MdeModulePkg/MdeModulePkg.dec
> +  RedfishPkg/RedfishPkg.dec
> +
> +[Sources]
> +  RestJsonStructureDxe.c
> +  RestJsonStructureInternal.h
> +
> +[LibraryClasses]
> +  BaseLib
> +  BaseMemoryLib
> +  MemoryAllocationLib
> +  UefiBootServicesTableLib
> +  UefiDriverEntryPoint
> +  UefiLib
> +
> +[Protocols]
> +  gEfiRestJsonStructureProtocolGuid    ## Producing
> +
> +[Depex]
> +  TRUE
> +
> diff --git a/RedfishPkg/RestJsonStructureDxe/RestJsonStructureInternal.h
> b/RedfishPkg/RestJsonStructureDxe/RestJsonStructureInternal.h
> new file mode 100644
> index 0000000000..e8a3408404
> --- /dev/null
> +++ b/RedfishPkg/RestJsonStructureDxe/RestJsonStructureInternal.h
> @@ -0,0 +1,33 @@
> +/** @file
> +  The internal definitions of EFI REST Resource JSON to C structure convertor
> +  Protocol.
> +
> +  (C) Copyright 2020 Hewlett Packard Enterprise Development LP<BR>
> +
> +  SPDX-License-Identifier: BSD-2-Clause-Patent
> +
> +**/
> +
> +#ifndef EFI_REST_JSON_STRUCTURE_INTERNAL_H_
> +#define EFI_REST_JSON_STRUCTURE_INTERNAL_H_
> +
> +#include <Library/BaseLib.h>
> +#include <Library/UefiLib.h>
> +#include <Library/UefiBootServicesTableLib.h>
> +#include <Library/UefiDriverEntryPoint.h>
> +#include <Library/BaseMemoryLib.h>
> +#include <Library/MemoryAllocationLib.h>
> +
> +///
> +/// Internal structure to maintain the information of JSON to
> +/// C structure convertor.
> +///
> +typedef struct _REST_JSON_STRUCTURE_INSTANCE {
> +  LIST_ENTRY NextRestJsonStructureInstance;  ///< Next convertor instance
> +  UINTN NumberOfNameSpaceToConvert;          ///< Number of resource
> type this convertor supports.
> +  EFI_REST_JSON_RESOURCE_TYPE_IDENTIFIER
> *SupportedRsrcIndentifier; ///< The resource type linklist
> +  EFI_REST_JSON_STRUCTURE_TO_STRUCTURE        JsonToStructure;
> ///< JSON to C structure function
> +  EFI_REST_JSON_STRUCTURE_TO_JSON             StructureToJson;          ///< C
> structure to JSON function
> +  EFI_REST_JSON_STRUCTURE_DESTORY_STRUCTURE   DestroyStructure;
> ///< Destory C struture function.
> +} REST_JSON_STRUCTURE_INSTANCE;
> +#endif
> --
> 2.17.1