public function handleRequest(AphrontRequest $request)
 {
     $response = $this->loadDiffusionContext();
     if ($response) {
         return $response;
     }
     $viewer = $this->getViewer();
     $drequest = $this->getDiffusionRequest();
     if (!$request->isAjax()) {
         // This request came out of the dropdown menu, either "View Standalone"
         // or "View Raw File".
         $view = $request->getStr('view');
         if ($view == 'r') {
             $uri = $drequest->generateURI(array('action' => 'browse', 'params' => array('view' => 'raw')));
         } else {
             $uri = $drequest->generateURI(array('action' => 'change'));
         }
         return id(new AphrontRedirectResponse())->setURI($uri);
     }
     $data = $this->callConduitWithDiffusionRequest('diffusion.diffquery', array('commit' => $drequest->getCommit(), 'path' => $drequest->getPath()));
     $drequest->updateSymbolicCommit($data['effectiveCommit']);
     $raw_changes = ArcanistDiffChange::newFromConduit($data['changes']);
     $diff = DifferentialDiff::newEphemeralFromRawChanges($raw_changes);
     $changesets = $diff->getChangesets();
     $changeset = reset($changesets);
     if (!$changeset) {
         return new Aphront404Response();
     }
     $parser = new DifferentialChangesetParser();
     $parser->setUser($viewer);
     $parser->setChangeset($changeset);
     $parser->setRenderingReference($drequest->generateURI(array('action' => 'rendering-ref')));
     $parser->readParametersFromRequest($request);
     $coverage = $drequest->loadCoverage();
     if ($coverage) {
         $parser->setCoverage($coverage);
     }
     $commit = $drequest->loadCommit();
     $pquery = new DiffusionPathIDQuery(array($changeset->getFilename()));
     $ids = $pquery->loadPathIDs();
     $path_id = $ids[$changeset->getFilename()];
     $parser->setLeftSideCommentMapping($path_id, false);
     $parser->setRightSideCommentMapping($path_id, true);
     $parser->setCanMarkDone($commit->getAuthorPHID() && $viewer->getPHID() == $commit->getAuthorPHID());
     $parser->setObjectOwnerPHID($commit->getAuthorPHID());
     $parser->setWhitespaceMode(DifferentialChangesetParser::WHITESPACE_SHOW_ALL);
     $inlines = PhabricatorAuditInlineComment::loadDraftAndPublishedComments($viewer, $commit->getPHID(), $path_id);
     if ($inlines) {
         foreach ($inlines as $inline) {
             $parser->parseInlineComment($inline);
         }
         $phids = mpull($inlines, 'getAuthorPHID');
         $handles = $this->loadViewerHandles($phids);
         $parser->setHandles($handles);
     }
     $engine = new PhabricatorMarkupEngine();
     $engine->setViewer($viewer);
     foreach ($inlines as $inline) {
         $engine->addObject($inline, PhabricatorInlineCommentInterface::MARKUP_FIELD_BODY);
     }
     $engine->process();
     $parser->setMarkupEngine($engine);
     $spec = $request->getStr('range');
     list($range_s, $range_e, $mask) = DifferentialChangesetParser::parseRangeSpecification($spec);
     $parser->setRange($range_s, $range_e);
     $parser->setMask($mask);
     return id(new PhabricatorChangesetResponse())->setRenderedChangeset($parser->renderChangeset())->setUndoTemplates($parser->getRenderer()->renderUndoTemplates());
 }