When importing events, delete events which have been removed on the other end

Summary: Ref T10747. If stuff has been deleted on the other calendar, delete it on ours.

Test Plan:
Imported with deletion, saw deletions:

{F1889689}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10747

Differential Revision: https://secure.phabricator.com/D16768

src/__phutil_library_map__.php

@@ -2111,6 +2111,7 @@ phutil_register_library_map(array(
     'PhabricatorCalendarImport' => 'applications/calendar/storage/PhabricatorCalendarImport.php',
     'PhabricatorCalendarImportDefaultLogType' => 'applications/calendar/importlog/PhabricatorCalendarImportDefaultLogType.php',
     'PhabricatorCalendarImportDeleteController' => 'applications/calendar/controller/PhabricatorCalendarImportDeleteController.php',
+    'PhabricatorCalendarImportDeleteLogType' => 'applications/calendar/importlog/PhabricatorCalendarImportDeleteLogType.php',
     'PhabricatorCalendarImportDeleteTransaction' => 'applications/calendar/xaction/PhabricatorCalendarImportDeleteTransaction.php',
     'PhabricatorCalendarImportDisableController' => 'applications/calendar/controller/PhabricatorCalendarImportDisableController.php',
     'PhabricatorCalendarImportDisableTransaction' => 'applications/calendar/xaction/PhabricatorCalendarImportDisableTransaction.php',
@@ -6965,6 +6966,7 @@ phutil_register_library_map(array(
     ),
     'PhabricatorCalendarImportDefaultLogType' => 'PhabricatorCalendarImportLogType',
     'PhabricatorCalendarImportDeleteController' => 'PhabricatorCalendarController',
+    'PhabricatorCalendarImportDeleteLogType' => 'PhabricatorCalendarImportLogType',
     'PhabricatorCalendarImportDeleteTransaction' => 'PhabricatorCalendarImportTransactionType',
     'PhabricatorCalendarImportDisableController' => 'PhabricatorCalendarController',
     'PhabricatorCalendarImportDisableTransaction' => 'PhabricatorCalendarImportTransactionType',

src/applications/calendar/import/PhabricatorCalendarImportEngine.php

@@ -409,10 +409,28 @@ abstract class PhabricatorCalendarImportEngine
         array());
     }
 
-    // TODO: When the source is a subscription-based ICS file or some other
-    // similar source, we should load all events from the source here and
-    // destroy the ones we didn't update. These are events that have been
-    // deleted.
+    // Delete any events which are no longer present in the source.
+    $updated_events = mpull($update_map, null, 'getPHID');
+    $source_events = id(new PhabricatorCalendarEventQuery())
+      ->setViewer($viewer)
+      ->withImportSourcePHIDs(array($import->getPHID()))
+      ->execute();
+
+    $engine = new PhabricatorDestructionEngine();
+    foreach ($source_events as $source_event) {
+      if (isset($updated_events[$source_event->getPHID()])) {
+        // We imported and updated this event, so keep it around.
+        continue;
+      }
+
+      $import->newLogMessage(
+        PhabricatorCalendarImportDeleteLogType::LOGTYPE,
+        array(
+          'name' => $source_event->getName(),
+        ));
+
+      $engine->destroyObject($source_event);
+    }
   }
 
   private function getFullNodeUID(PhutilCalendarEventNode $node) {

src/applications/calendar/importlog/PhabricatorCalendarImportDeleteLogType.php

@@ -0,0 +1,34 @@
+<?php
+
+final class PhabricatorCalendarImportDeleteLogType
+  extends PhabricatorCalendarImportLogType {
+
+  const LOGTYPE = 'delete';
+
+  public function getDisplayType(
+    PhabricatorUser $viewer,
+    PhabricatorCalendarImportLog $log) {
+    return pht('Deleted Event');
+  }
+
+  public function getDisplayDescription(
+    PhabricatorUser $viewer,
+    PhabricatorCalendarImportLog $log) {
+    return pht(
+      'Deleted event "%s" which is no longer present in the source.',
+      $log->getParameter('name'));
+  }
+
+  public function getDisplayIcon(
+    PhabricatorUser $viewer,
+    PhabricatorCalendarImportLog $log) {
+    return 'fa-times';
+  }
+
+  public function getDisplayColor(
+    PhabricatorUser $viewer,
+    PhabricatorCalendarImportLog $log) {
+    return 'grey';
+  }
+
+}