Fix bug in DataHub where it would skip the first record in a set when a filter is being used. Also add comments and update source code logic to make it easier to understand and maintain.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11008 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 63 insertions, 52 deletions

diff --git a/IntelFrameworkModulePkg/Universal/DataHubDxe/DataHub.c b/IntelFrameworkModulePkg/Universal/DataHubDxe/DataHub.c
index dad529bd38..e4dfa29d69 100644
--- a/IntelFrameworkModulePkg/Universal/DataHubDxe/DataHub.c
+++ b/IntelFrameworkModulePkg/Universal/DataHubDxe/DataHub.c
@@ -286,85 +286,96 @@ DataHubGetNextRecord (
   DATA_HUB_INSTANCE       *Private;

   DATA_HUB_FILTER_DRIVER  *FilterDriver;

   UINT64                  ClassFilter;

-  UINT64                  FilterMonotonicCount;

 

   Private               = DATA_HUB_INSTANCE_FROM_THIS (This);

 

   FilterDriver          = NULL;

-  FilterMonotonicCount  = 0;

   ClassFilter = EFI_DATA_RECORD_CLASS_DEBUG |

     EFI_DATA_RECORD_CLASS_ERROR |

     EFI_DATA_RECORD_CLASS_DATA |

     EFI_DATA_RECORD_CLASS_PROGRESS_CODE;

 

-  if (FilterDriverEvent != NULL) {

-    //

-    // For events the beginning is the last unread record. This info is

-    // stored in the instance structure, so we must look up the event

-    // to get the data.

-    //

-    FilterDriver = FindFilterDriverByEvent (

-                    &Private->FilterDriverListHead,

-                    *FilterDriverEvent

-                    );

-    if (FilterDriver == NULL) {

-      return EFI_INVALID_PARAMETER;

+  //

+  // If FilterDriverEvent is NULL, then return the next record

+  //

+  if (FilterDriverEvent == NULL) {

+    *Record = GetNextDataRecord (&Private->DataListHead, ClassFilter, MonotonicCount);

+    if (*Record == NULL) {

+      return EFI_NOT_FOUND;

     }

-    //

-    // Use the Class filter the event was created with.

-    //

-    ClassFilter = FilterDriver->ClassFilter;

+    return EFI_SUCCESS;

+  }

+    

+  //

+  // For events the beginning is the last unread record. This info is

+  // stored in the instance structure, so we must look up the event

+  // to get the data.

+  //

+  FilterDriver = FindFilterDriverByEvent (

+                  &Private->FilterDriverListHead,

+                  *FilterDriverEvent

+                  );

+  if (FilterDriver == NULL) {

+    return EFI_INVALID_PARAMETER;

+  }

+  //

+  // Use the Class filter the event was created with.

+  //

+  ClassFilter = FilterDriver->ClassFilter;

 

-    if (*MonotonicCount == 0) {

+  //

+  // Retrieve the next record or the first record.

+  //   

+  if (*MonotonicCount != 0 || FilterDriver->GetNextMonotonicCount == 0) { 

+    *Record = GetNextDataRecord (&Private->DataListHead, ClassFilter, MonotonicCount);

+    if (*Record == NULL) {

+      return EFI_NOT_FOUND;

+    }

+    

+    if (*MonotonicCount != 0) {

       //

-      // Use the MTC from the Filter Driver.

+      // If this was not the last record then update the count associated with the filter 

       //

-      FilterMonotonicCount = FilterDriver->GetNextMonotonicCount;

-       

+      FilterDriver->GetNextMonotonicCount = *MonotonicCount;

+    } else {

       //

-      // The GetNextMonotonicCount field remembers the last value from the previous time.

-      // But we already processed this vaule, so we need to find the next one.

+      // Save the MonotonicCount of the last record which has been read

       //

-      *Record = GetNextDataRecord (&Private->DataListHead, ClassFilter, &FilterMonotonicCount);

-      if (FilterMonotonicCount != 0) {

-        *MonotonicCount = FilterMonotonicCount;

-      }

-      

-      if ((FilterDriver->GetNextMonotonicCount != 0) && (FilterMonotonicCount == 0)) {

-        //

-        // If there is no new record to get exit now.

-        //

-        *MonotonicCount = 0;

-        return EFI_NOT_FOUND;

-      }

+      FilterDriver->GetNextMonotonicCount = (*Record)->LogMonotonicCount;

     }

+    return EFI_SUCCESS;

   }

+  

   //

-  // Return the record

+  // This is a request to read the first record that has not been read yet.  

+  // Set MonotoicCount to the last record successfuly read

+  //

+  *MonotonicCount = FilterDriver->GetNextMonotonicCount;

+  

+  //

+  // Retrieve the last record successfuly read again, but do not return it since

+  // it has already been returned before.

   //

   *Record = GetNextDataRecord (&Private->DataListHead, ClassFilter, MonotonicCount);

   if (*Record == NULL) {

     return EFI_NOT_FOUND;

   }

-

-  if (FilterDriver != NULL) {

+  

+  if (*MonotonicCount != 0) {

     //

-    // If we have a filter driver update the records that have been read.

-    // If MonotonicCount is zero No more reacords left.

+    // Update the count associated with the filter 

     //

-    if (*MonotonicCount == 0) {

-      //

-      // Save the current Record MonotonicCount.

-      //

-      FilterDriver->GetNextMonotonicCount = (*Record)->LogMonotonicCount;

-    } else {

-      //

-      // Point to next undread record

-      //

-      FilterDriver->GetNextMonotonicCount = *MonotonicCount;

+    FilterDriver->GetNextMonotonicCount = *MonotonicCount;

+

+    //

+    // Retrieve the record after the last record successfuly read 

+    //  

+    *Record = GetNextDataRecord (&Private->DataListHead, ClassFilter, MonotonicCount);

+    if (*Record == NULL) {

+      return EFI_NOT_FOUND;

     }

   }

-

+  

   return EFI_SUCCESS;

 }