Json: keep item order when renaming key & make sure to truncate file on save

Author: ollydev

Source/simba.json.pas

@@ -229,10 +229,31 @@ procedure TSimbaJSONItemHelper.SetAsUnicodeString(AValue: UnicodeString);
 end;
 
 procedure TSimbaJSONItemHelper.SetKey(Index: Integer; AValue: String);
+var
+  Items: array of record
+    Key: TJSONStringType;
+    Value: TJSONData;
+  end;
+  I: Integer;
 begin
   CheckIsObject();
+  if (Index < 0) or (Index >= TJSONObject(Self).Count) then
+    SimbaException('Index %d is out of range', [Index]);
+
+  // not ideal since FPC doesn't provide access to FHashList but should be fine
+  // no new objects are made, just rehashing
+  SetLength(Items, TJSONObject(Self).Count);
+  I := High(Items); // looping down probs more efficent for deletes
+  while (TJSONObject(Self).Count > 0) do
+  begin
+    Items[I].Key   := TJSONObject(Self).Names[I];
+    Items[I].Value := TJSONObject(Self).Extract(I);
+    Dec(I);
+  end;
 
-  TJSONObject(Self).Add(AValue, TJSONObject(Self).Extract(Index));
+  Items[Index].Key := AValue;
+  for I := 0 to High(Items) do
+    TJSONObject(Self).Add(Items[I].Key, Items[I].Value);
 end;
 
 procedure TSimbaJSONItemHelper.Add(AKey: String; Value: TSimbaJSONItem);
@@ -461,7 +482,7 @@ procedure TSimbaJSONItemHelper.Save(FileName: String; Options: EJSONFormatOption
   else
     Stream := TFileStream.Create(FileName, fmCreate);
   try
-    Stream.Write(Text[1], Length(Text));
+    Stream.Size := Stream.Write(Text[1], Length(Text));
   finally
     Stream.Free();
   end;

Tests/json.simba

@@ -58,8 +58,13 @@ begin
     '  "obj" : {}'                          + LINE_SEP +
     '}'
   );
-  json.Key[0] := 'text';
-  Assert(json.Has('text', EJSONType.STR));
+
+  Assert(json.key[0] = 'str');
+  Assert(json.key[4] = 'arr');
+  json.Key[0] := 'str_but_renamed';
+  json.Key[4] := 'arr_but_renamed';
+  Assert(json.key[0] = 'str_but_renamed');
+  Assert(json.key[4] = 'arr_but_renamed');
 end;
 
 procedure TestParseArray;