Update function comments HiiLibListPackageLists

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@5961 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Library/HiiLib/HiiLib.c

@@ -573,13 +573,49 @@ HiiLibExportPackageLists (
   return Status;
 }
 
+/**
+  
+  This function returns a list of the package handles of the   
+  specified type that are currently active in the HII database. The   
+  pseudo-type EFI_HII_PACKAGE_TYPE_ALL will cause all package   
+  handles to be listed.
 
+  If HandleBufferLength is NULL, then ASSERT.
+  If HandleBuffer is NULL, the ASSERT.
+  If PackageType is EFI_HII_PACKAGE_TYPE_GUID and PackageGuid is
+  NULL, then ASSERT.
+  If PackageType is not EFI_HII_PACKAGE_TYPE_GUID and PackageGuid is not
+  NULL, then ASSERT.
+  
+  
+  @param PackageType          Specifies the package type of the packages
+                              to list or EFI_HII_PACKAGE_TYPE_ALL for
+                              all packages to be listed.
+  
+  @param PackageGuid          If PackageType is
+                              EFI_HII_PACKAGE_TYPE_GUID, then this is
+                              the pointer to the GUID which must match
+                              the Guid field of
+                              EFI_HII_PACKAGE_GUID_HEADER. Otherwise, it
+                              must be NULL.
+  
+  @param HandleBufferLength   On output, the length of the handle buffer
+                              that is required for the handles found.
+
+  @param HandleBuffer         On output, an array of EFI_HII_HANDLE  instances returned.
+                              The caller is responcible to free this pointer allocated.
+
+  @retval EFI_SUCCESS           The matching handles are outputed successfully.
+                                HandleBufferLength is updated with the actual length.
+  @retval EFI_OUT_OF_RESOURCES  Not enough resource to complete the operation.
+  @retval EFI_NOT_FOUND         No matching handle could not be found in database.
+**/
 EFI_STATUS
 EFIAPI
 HiiLibListPackageLists (
   IN        UINT8                     PackageType,
   IN CONST  EFI_GUID                  *PackageGuid,
-  IN OUT    UINTN                     *HandleBufferLength,
+  OUT    UINTN                        *HandleBufferLength,
   OUT       EFI_HII_HANDLE            **HandleBuffer
   )
 {
@@ -591,6 +627,12 @@ HiiLibListPackageLists (
   *HandleBufferLength = 0;
   *HandleBuffer       = NULL;
 
+  if (PackageType == EFI_HII_PACKAGE_TYPE_GUID) {
+    ASSERT (PackageGuid != NULL);
+  } else {
+    ASSERT (PackageGuid == NULL);
+  }
+
   Status = mHiiDatabaseProt->ListPackageLists (
                             mHiiDatabaseProt,
                             PackageType,
@@ -600,7 +642,7 @@ HiiLibListPackageLists (
                             );
   if (EFI_ERROR (Status) && (Status != EFI_BUFFER_TOO_SMALL)) {
     //
-    // No packages is registered to UEFI HII Database, just return EFI_SUCCESS.
+    // No packages is registered to UEFI HII Database, just return.
     // 
     //
     return Status;