fcl-db: bufdataset: Fix wrong initialization of OrgBufID in new blob buffer.

git-svn-id: trunk@24802 -

packages/fcl-db/src/base/bufdataset.pas

@@ -2266,25 +2266,26 @@ var r            : Integer;
 
 begin
   for r:=0 to length(FUpdateBuffer)-1 do
-   if assigned(FUpdateBuffer[r].OldValuesBuffer) then
+    if assigned(FUpdateBuffer[r].OldValuesBuffer) then
       FreeMem(FUpdateBuffer[r].OldValuesBuffer);
   SetLength(FUpdateBuffer,0);
 
   if assigned(FUpdateBlobBuffers) then for r:=0 to length(FUpdateBlobBuffers)-1 do
-   if assigned(FUpdateBlobBuffers[r]) then
-    begin
-    if FUpdateBlobBuffers[r]^.OrgBufID >= 0 then
+    if assigned(FUpdateBlobBuffers[r]) then
       begin
-      FreeBlobBuffer(FBlobBuffers[FUpdateBlobBuffers[r]^.OrgBufID]);
-      FBlobBuffers[FUpdateBlobBuffers[r]^.OrgBufID] :=FUpdateBlobBuffers[r];
-      end
-    else
-      begin
-      setlength(FBlobBuffers,length(FBlobBuffers)+1);
-      FUpdateBlobBuffers[r]^.OrgBufID := high(FBlobBuffers);
-      FBlobBuffers[high(FBlobBuffers)] := FUpdateBlobBuffers[r];
+      // update blob buffer is already referenced from record buffer (see InternalPost)
+      if FUpdateBlobBuffers[r]^.OrgBufID >= 0 then
+        begin
+        FreeBlobBuffer(FBlobBuffers[FUpdateBlobBuffers[r]^.OrgBufID]);
+        FBlobBuffers[FUpdateBlobBuffers[r]^.OrgBufID] := FUpdateBlobBuffers[r];
+        end
+      else
+        begin
+        setlength(FBlobBuffers,length(FBlobBuffers)+1);
+        FUpdateBlobBuffers[r]^.OrgBufID := high(FBlobBuffers);
+        FBlobBuffers[high(FBlobBuffers)] := FUpdateBlobBuffers[r];
+        end;
       end;
-    end;
   SetLength(FUpdateBlobBuffers,0);
 end;
 
@@ -2542,7 +2543,7 @@ begin
   setlength(FBlobBuffers,length(FBlobBuffers)+1);
   new(ABlobBuffer);
   fillbyte(ABlobBuffer^,sizeof(ABlobBuffer^),0);
-  ABlobBuffer^.OrgBufID := high(FUpdateBlobBuffers);
+  ABlobBuffer^.OrgBufID := high(FBlobBuffers);
   FBlobBuffers[high(FBlobBuffers)] := ABlobBuffer;
   result := ABlobBuffer;
 end;

packages/fcl-db/tests/testdbbasics.pas

@@ -1574,7 +1574,7 @@ procedure TTestBufDatasetDBBasics.TestMergeChangeLog;
 var
   ds: TCustomBufDataset;
   i: integer;
-  s: string;
+  s, FN: string;
 begin
   ds := DBConnector.GetNDataset(5) as TCustomBufDataset;
   with ds do
@@ -1604,6 +1604,27 @@ begin
     checkequals(fields[0].OldValue,23);
     checkequals(fields[1].OldValue,'hanged');
     end;
+
+  // Test handling of [Update]BlobBuffers in TBufDataset
+  ds := DBConnector.GetFieldDataset as TCustomBufDataset;
+  with ds do
+    begin
+    // Testing scenario: read some records, so blob data are added into FBlobBuffers,
+    // then update blob field, so element is added to FUpdateBlobBuffers, then read again some records
+    // so next elements are added to FBlobBuffers, then again update blob field
+    // DefaultBufferCount is 10
+    PacketRecords:=1;
+    Open;
+    FN := 'F'+FieldTypeNames[ftBlob];
+    First;     Edit; FieldByName(FN).AsString:='b01'; Post;
+    RecNo:=11; Edit; FieldByName(FN).AsString:='b11'; Post;
+    Next     ; Edit; FieldByName(FN).AsString:='b12'; Post;
+    Last;
+    MergeChangeLog;
+    First;     CheckEquals('b01', FieldByName(FN).AsString);
+    RecNo:=11; CheckEquals('b11', FieldByName(FN).AsString);
+    Next;      CheckEquals('b12', FieldByName(FN).AsString);
+    end;
 end;
 
 procedure TTestBufDatasetDBBasics.FTestXMLDatasetDefinition(ADataset: TDataset);