Add estimation of shuffle time

src/tool/tool_js_common.ml

@@ -92,6 +92,10 @@ let clear_content (e : #Dom.node Js.t) =
     ()
   done
 
+let clear_content_by_id id =
+  document##getElementById (Js.string id) >>== fun e ->
+  clear_content e
+
 let run_handler handler () =
   (try handler ()
    with e ->

src/tool/tool_js_shuffle.ml

@@ -24,28 +24,76 @@ open Serializable_j
 open Common
 open Tool_js_common
 
+let eta = ref 0
+
 let shuffle election ciphertexts =
   let election = Election.(get_group (of_string election)) in
   let module W = (val election) in
   let module E = Election.Make (W) (LwtJsRandom) in
   let ciphertexts = nh_ciphertexts_of_string E.G.read ciphertexts in
-  let%lwt shuffle = E.shuffle_ciphertexts ciphertexts in
-  Lwt.return (string_of_shuffle E.G.write shuffle)
+  let full_shuffle () =
+    let id =
+      if !eta > 0 then
+        let start = (new%js Js.date_now)##valueOf in
+        let stop = start +. float_of_int !eta *. 1000. in
+        let update () =
+          let now = (new%js Js.date_now)##valueOf in
+          let eta = max 0 (int_of_float (ceil ((stop -. now) /. 1000.))) in
+          clear_content_by_id "estimation";
+          set_content "estimation"
+            (Printf.sprintf "Estimated remaining time: %d second(s)" eta)
+        in
+        Some (Dom_html.window##setInterval (Js.wrap_callback update) 500.)
+      else
+        None
+    in
+    let%lwt shuffle = E.shuffle_ciphertexts ciphertexts in
+    let r = string_of_shuffle E.G.write shuffle in
+    let () =
+      match id with
+      | Some x ->
+         Dom_html.window##clearInterval x;
+         clear_content_by_id "estimation";
+      | None -> ()
+    in
+    Lwt.return r
+  in
+  let bench_shuffle () =
+    let n =
+      Array.fold_left (fun accu x -> accu + Array.length x) 0 ciphertexts
+    in
+    let%lwt x = LwtJsRandom.random E.G.q in
+    let start = new%js Js.date_now in
+    let _ = E.G.(g **~ x) in
+    let stop = new%js Js.date_now in
+    set_element_display "controls_div" "block";
+    set_element_display "wait_div" "none";
+    let delta = (stop##valueOf -. start##valueOf) /. 1000. in
+    (* cost is 11n+7 modpows, we add another n for the overhead *)
+    eta := int_of_float (ceil (delta *. float_of_int (12 * n + 7)));
+    clear_content_by_id "estimation";
+    set_content "estimation"
+      (Printf.sprintf "Estimated computation time: %d second(s)" !eta);
+    Lwt.return_unit
+  in
+  Lwt.async bench_shuffle;
+  full_shuffle
 
 let () =
   Lwt.async (fun () ->
       let%lwt _ = Lwt_js_events.onload () in
+      let uuid = List.assoc "uuid" (get_params ()) in
+      let open Lwt_xmlHttpRequest in
+      let%lwt election = get ("../elections/" ^ uuid ^ "/election.json") in
+      let%lwt ciphertexts = get ("../election/nh-ciphertexts?uuid=" ^ uuid) in
+      let full_shuffle = shuffle election.content ciphertexts.content in
       match Dom_html.getElementById_coerce "compute_shuffle" Dom_html.CoerceTo.button with
       | None -> Lwt.return_unit
       | Some btn ->
          let%lwt _ = Lwt_js_events.click btn in
          set_element_display "controls_div" "none";
          set_element_display "wait_div" "block";
-         let uuid = List.assoc "uuid" (get_params ()) in
-         let open Lwt_xmlHttpRequest in
-         let%lwt election = get ("../elections/" ^ uuid ^ "/election.json") in
-         let%lwt ciphertexts = get ("../election/nh-ciphertexts?uuid=" ^ uuid) in
-         let%lwt shuffle = shuffle election.content ciphertexts.content in
+         let%lwt shuffle = full_shuffle () in
          set_textarea "shuffle" shuffle;
          set_element_display "wait_div" "none";
          set_content "hash" (Platform.sha256_b64 shuffle);

src/web/web_templates.ml

@@ -2592,10 +2592,13 @@ let shuffle election token =
   let title = params.e_name ^ " — Shuffle" in
   let content = [
       div [pcdata "It is now time to shuffle encrypted ballots."];
-      div ~a:[a_id "controls_div"] [
+      div ~a:[a_id "estimation"] [
+          pcdata "Estimating computation time...";
+        ];
+      div ~a:[a_id "controls_div"; a_style "display: none;"] [
           button_no_value ~button_type:`Button ~a:[a_id "compute_shuffle"] [pcdata "Compute shuffle"];
         ];
-      div ~a:[a_id "wait_div"; a_style "display:none;"] [
+      div ~a:[a_id "wait_div"] [
           pcdata "Please wait... ";
           img ~src:(static "encrypting.gif") ~alt:"Loading..." ();
         ];

tests/test_scenario_3.py

@@ -6,7 +6,7 @@ import os
 import sys
 from distutils.util import strtobool
 from util.fake_sent_emails_manager import FakeSentEmailsManager
-from util.selenium_tools import wait_for_element_exists, wait_for_an_element_with_partial_link_text_exists, wait_for_element_exists_and_has_non_empty_attribute, wait_for_element_exists_and_contains_expected_text
+from util.selenium_tools import wait_for_element_exists, wait_for_an_element_with_partial_link_text_exists, wait_for_element_exists_and_has_non_empty_attribute, wait_for_element_exists_and_contains_expected_text, wait_for_element_visible
 from util.election_testing import console_log, remove_database_folder, wait_a_bit, build_css_selector_to_find_buttons_in_page_content_by_value, initialize_server, initialize_browser, verify_election_consistency, create_election_data_snapshot, delete_election_data_snapshot, log_in_as_administrator, log_out
 from util.election_test_base import BeleniosElectionTestBase
 import settings
@@ -82,7 +82,7 @@ class BeleniosTestElectionScenario1(BeleniosElectionTestBase):
         wait_a_bit()
 
         # She clicks on the "Compute shuffle" button
-        wait_for_element_exists(browser, "#compute_shuffle", settings.EXPLICIT_WAIT_TIMEOUT).click()
+        wait_for_element_visible(browser, "#compute_shuffle", settings.EXPLICIT_WAIT_TIMEOUT).click()
         wait_a_bit()
 
         # She waits for the "shuffle" textarea to be filled

tests/util/selenium_tools.py

@@ -143,6 +143,13 @@ def wait_for_element_exists(browser, css_selector, wait_duration=DEFAULT_WAIT_DU
     except Exception as e:
         raise Exception("Could not find expected DOM element '" + css_selector + "' until timeout of " + str(wait_duration) + " seconds") from e
 
+def wait_for_element_visible(browser, css_selector, wait_duration=DEFAULT_WAIT_DURATION):
+    try:
+        return WebDriverWait(browser, wait_duration).until(
+            EC.visibility_of_element_located((By.CSS_SELECTOR, css_selector))
+        )
+    except Exception as e:
+        raise Exception("Could not find expected visible DOM element '" + css_selector + "' until timeout of " + str(wait_duration) + " seconds") from e
 
 def wait_for_elements_exist(browser, css_selector, wait_duration=DEFAULT_WAIT_DURATION):
     try: