zoneminder/web/js/table-helpers.js

'use strict';

// Helpers shared by the bootstrap-table views (events, console, log, frames,
// reports, snapshots, watch). Loaded as a plain browser script before the view
// scripts (web/skins/classic/includes/functions.php), so the functions below are
// globals by the time any of them runs. Also CommonJS-exported for node unit
// tests (tests/js/table-helpers.test.js).

// The icons the bootstrap-table top-right toolbar is built with. Every view
// that makes a table passes these to bootstrapTable(), so they have to exist
// before the view scripts run. They used to live in skin.js, which the footer
// loads last of all: a client that never got that far -- a crawler that stops
// short, an aborted load -- ran the view's ready handler against an undefined
// icons and threw.
var icons = {
  paginationSwitchDown: 'fa-caret-square-o-down',
  paginationSwitchUp: 'fa-caret-square-o-up',
  export: 'fa-download',
  refresh: 'fa-retweet',
  autoRefresh: 'fa-clock-o',
  advancedSearchIcon: 'fa-chevron-down',
  toggleOff: 'fa-toggle-off',
  toggleOn: 'fa-toggle-on',
  columns: 'fa-th-list',
  fullscreen: 'fa-arrows-alt',
  detailOpen: 'fa-plus',
  detailClose: 'fa-minus'
};

// Tables whose ajax request was skipped because the page was hidden, waiting to
// be refreshed once it is shown again.
const tablesPendingVisibility = [];

// Decide whether to skip a bootstrap-table ajax request because the page is
// hidden. Returns true when the caller should return without issuing it.
//
// Skipping alone is not enough. Bootstrap-table calls its ajax function on init
// as well as on refresh, and a skipped request is never re-issued, so the table
// renders "No matching records found" over a result it never asked for. Nothing
// brings it back and the user has to refresh by hand (issue #5026). Recording
// the table here means it is refreshed the moment the page becomes visible.
//
// A page can be hidden for the whole of its load - opened in a background tab,
// restored, or simply behind another window - so this is not only about a tab
// the user switched away from later.
function deferTableRequestWhileHidden(table) {
  if (document.visibilityState !== 'hidden') return false;
  table.bootstrapTable('hideLoading');
  // A table can be deferred repeatedly (init, then auto-refresh ticks) and only
  // needs refreshing once.
  if (tablesPendingVisibility.indexOf(table) === -1) {
    tablesPendingVisibility.push(table);
  }
  return true;
}

// Refresh every table whose request was skipped while hidden. The auth hash we
// were holding may have expired during the hide, so wait for a confirmed one
// rather than have every deferred table 403 (auth-helpers.js). whenAuthFresh is
// absent under node; refresh directly there.
function refreshTablesPendingVisibility() {
  if (document.visibilityState === 'hidden') return;
  // Drain before refreshing: refresh() calls the ajax function synchronously,
  // which would otherwise re-add the table while we are still iterating.
  const tables = tablesPendingVisibility.splice(0, tablesPendingVisibility.length);
  // Nothing was deferred, so there is nothing to authenticate for. This handler
  // is bound on every classic page including the unauthenticated ones, and
  // whenAuthFresh() can send a probe, so becoming visible must stay a no-op
  // when there is no work.
  if (!tables.length) return;
  const refresh = function() {
    for (let i = 0; i < tables.length; i++) {
      tables[i].bootstrapTable('refresh');
    }
  };
  if (typeof whenAuthFresh === 'function') {
    whenAuthFresh(refresh);
  } else {
    refresh();
  }
}

if (typeof document !== 'undefined' && document.addEventListener) {
  document.addEventListener('visibilitychange', refreshTablesPendingVisibility);
}

if (typeof module !== 'undefined' && module.exports) {
  module.exports = {
    icons,
    deferTableRequestWhileHidden,
    refreshTablesPendingVisibility,
    tablesPendingVisibility,
  };
}