prevents users from deleting already deleted/moved phriction documents

Summary:
Deps D5198 since it uses a constant from D5198

accidentalbigdiff

I sure doubled the size of this file ^^

Could be that I added unserious business.

Test Plan:
Created a page. Had it open in two browser windows. Deleted in one. This is the second attempt:

{F34458}

Reviewers: epriestley, btrahan

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5202

src/applications/phriction/controller/PhrictionDeleteController.php

@@ -21,15 +21,47 @@ final class PhrictionDeleteController extends PhrictionController {
       return new Aphront404Response();
     }
 
+    $error_view = null;
+    $disallowed_states = array(
+      PhrictionDocumentStatus::STATUS_DELETED, // Stupid
+      PhrictionDocumentStatus::STATUS_MOVED, // Makes no sense
+    );
+    if (in_array($document->getStatus(), $disallowed_states)) {
+      $is_serious =
+        PhabricatorEnv::getEnvConfig('phabricator.serious-business');
+
+      if ($is_serious) {
+        $e_text = pht('An already moved or deleted document can not be '.
+          'deleted');
+      } else {
+        $e_text = pht('I\'m not sure if you got the notice, but you can\'t '.
+          'delete an already deleted or moved document.');
+      }
+
+      $error_view = new AphrontErrorView();
+      $error_view->setSeverity(AphrontErrorView::SEVERITY_ERROR);
+      $error_view->setTitle(pht('Can not delete page'));
+      $error_view->appendChild($e_text);
+
+      $error_view = $error_view->render();
+    }
+
     $document_uri = PhrictionDocument::getSlugURI($document->getSlug());
 
-    if ($request->isFormPost()) {
+    if (!$error_view && $request->isFormPost()) {
         $editor = id(PhrictionDocumentEditor::newForSlug($document->getSlug()))
           ->setActor($user)
           ->delete();
         return id(new AphrontRedirectResponse())->setURI($document_uri);
     }
 
+    if ($error_view) {
+      $dialog = id(new AphrontDialogView())
+        ->setUser($user)
+        ->setTitle(pht('Error!'))
+        ->appendChild($error_view)
+        ->addCancelButton($document_uri);
+    } else {
       $dialog = id(new AphrontDialogView())
         ->setUser($user)
         ->setTitle(pht('Delete document?'))
@@ -38,6 +70,7 @@ final class PhrictionDeleteController extends PhrictionController {
           'reverting to a previous version.'))
         ->addSubmitButton(pht('Delete'))
         ->addCancelButton($document_uri);
+    }
 
     return id(new AphrontDialogResponse())->setDialog($dialog);
   }