This merge request implements the `httpapi.dll` `HttpResponseSendEntityBody` function and associated tests. API documentation was written by me by paraphrasing/re-writing what I had read for the function from the MSDN documentation. I am adding this function to enable the remote API component of the Space Engineers Dedicated Server.
Implementation notes: - I mainly copied the relevant portion of `HttpSendHttpResponse` for `HttpResponseSendEntityBody`. - I updated the `http_response` struct to add a field `response_flags` - This field tracks the flags passed in to `HttpSendHttpResponse` and `HttpResponseSendEntityBody`. - This was needed because the clean-up steps in `http.sys` need to be skipped when `HTTP_SEND_RESPONSE_FLAG_MORE_DATA` is set. - I updated `HttpSendHttpResponse` to handle the `HTTP_SEND_RESPONSE_FLAG_MORE_DATA` flag by omitting the `Content-Length` header and setting the `response_flags` field in the `response` object passed to `http.sys`. - The `Content-Length` header is omitted by the Windows implementation and thus I omitted it here for conformance purposes. - I updated `http_send_response` in `http.sys` to skip the connection clean up steps if the `HTTP_SEND_RESPONSE_FLAG_MORE_DATA` flag was set. This works for both `HttpSendHttpResponse` and `HttpResponseSendEntityBody` as either could set the flag to continue to send more data. - It is not 100% clear to me what the cleanup steps are doing. In particular, I am uncertain what lines 1011-1016 and 1023-1027 are doing, but based on context it seemed appropriate to keep them with the other connection cleanup steps.
For testing, I duplicated the existing `HttpSendHttpResponse` test but modified it to set the `HTTP_SEND_RESPONSE_FLAG_MORE_DATA` flag and then followed up with a call to `HttpResponseSendEntityBody` with new data. The validation ensures that data from both the initial response and follow up response are contained in the final response obtained via `recv()`. On Windows 11 this happens immediately without any delay, but in Wine I had to add a `Sleep(100)` to give enough time for the follow up response to be received in the socket buffer by the time the `recv()` call was made in the test. I could have looped the `recv()` call to collect all of the response, but that felt more complicated than adding a minor delay. The tests were verified against Windows 11 Pro (build 22621.3880).