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

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

> -----Original Message-----
> From: Wang, Nickle (HPS SW)
> Sent: Thursday, October 29, 2020 2:58 PM
> To: Chang, Abner (HPS SW/FW Technologist) <abner.chang@hpe.com>;
> 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>
> Subject: RE: [RestJsonStructureDxe PATCH v3 2/3]
> RedfishPkg/RestJsonStructureDxe: EFI REST JSON Structure Protocol
> 
> 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.
[Chang, Abner] 
Thanks for catching this. That issue is fixed in V4 (just sent) of patches set.

Abner

> 
> > +  //
> > +  // 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