Modularize SearchEngine extensions

Summary:
Ref T9964. ApplicationSearch currently has a bunch of hard-coded `if ($object instanceof thing)` stuff.

Pull that out so it can live in extensions.

Test Plan:
 - Searched by spaces, subscribers, projects.

{F1023921}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9964

Differential Revision: https://secure.phabricator.com/D14764

src/__phutil_library_map__.php

@@ -2836,9 +2836,10 @@ phutil_register_library_map(array(
     'PhabricatorProjectUserFunctionDatasource' => 'applications/project/typeahead/PhabricatorProjectUserFunctionDatasource.php',
     'PhabricatorProjectViewController' => 'applications/project/controller/PhabricatorProjectViewController.php',
     'PhabricatorProjectWatchController' => 'applications/project/controller/PhabricatorProjectWatchController.php',
-    'PhabricatorProjectsEditEngineExtension' => 'applications/project/editor/PhabricatorProjectsEditEngineExtension.php',
+    'PhabricatorProjectsEditEngineExtension' => 'applications/project/engineextension/PhabricatorProjectsEditEngineExtension.php',
     'PhabricatorProjectsEditField' => 'applications/transactions/editfield/PhabricatorProjectsEditField.php',
     'PhabricatorProjectsPolicyRule' => 'applications/project/policyrule/PhabricatorProjectsPolicyRule.php',
+    'PhabricatorProjectsSearchEngineExtension' => 'applications/project/engineextension/PhabricatorProjectsSearchEngineExtension.php',
     'PhabricatorProtocolAdapter' => 'infrastructure/daemon/bot/adapter/PhabricatorProtocolAdapter.php',
     'PhabricatorPygmentSetupCheck' => 'applications/config/check/PhabricatorPygmentSetupCheck.php',
     'PhabricatorQuery' => 'infrastructure/query/PhabricatorQuery.php',
@@ -3132,12 +3133,13 @@ phutil_register_library_map(array(
     'PhabricatorSubscriptionsAddSubscribersHeraldAction' => 'applications/subscriptions/herald/PhabricatorSubscriptionsAddSubscribersHeraldAction.php',
     'PhabricatorSubscriptionsApplication' => 'applications/subscriptions/application/PhabricatorSubscriptionsApplication.php',
     'PhabricatorSubscriptionsEditController' => 'applications/subscriptions/controller/PhabricatorSubscriptionsEditController.php',
-    'PhabricatorSubscriptionsEditEngineExtension' => 'applications/subscriptions/editor/PhabricatorSubscriptionsEditEngineExtension.php',
+    'PhabricatorSubscriptionsEditEngineExtension' => 'applications/subscriptions/engineextension/PhabricatorSubscriptionsEditEngineExtension.php',
     'PhabricatorSubscriptionsEditor' => 'applications/subscriptions/editor/PhabricatorSubscriptionsEditor.php',
     'PhabricatorSubscriptionsHeraldAction' => 'applications/subscriptions/herald/PhabricatorSubscriptionsHeraldAction.php',
     'PhabricatorSubscriptionsListController' => 'applications/subscriptions/controller/PhabricatorSubscriptionsListController.php',
     'PhabricatorSubscriptionsRemoveSelfHeraldAction' => 'applications/subscriptions/herald/PhabricatorSubscriptionsRemoveSelfHeraldAction.php',
     'PhabricatorSubscriptionsRemoveSubscribersHeraldAction' => 'applications/subscriptions/herald/PhabricatorSubscriptionsRemoveSubscribersHeraldAction.php',
+    'PhabricatorSubscriptionsSearchEngineExtension' => 'applications/subscriptions/engineextension/PhabricatorSubscriptionsSearchEngineExtension.php',
     'PhabricatorSubscriptionsSubscribeEmailCommand' => 'applications/subscriptions/command/PhabricatorSubscriptionsSubscribeEmailCommand.php',
     'PhabricatorSubscriptionsSubscribersPolicyRule' => 'applications/subscriptions/policyrule/PhabricatorSubscriptionsSubscribersPolicyRule.php',
     'PhabricatorSubscriptionsTransactionController' => 'applications/subscriptions/controller/PhabricatorSubscriptionsTransactionController.php',
@@ -7104,6 +7106,7 @@ phutil_register_library_map(array(
     'PhabricatorProjectsEditEngineExtension' => 'PhabricatorEditEngineExtension',
     'PhabricatorProjectsEditField' => 'PhabricatorTokenizerEditField',
     'PhabricatorProjectsPolicyRule' => 'PhabricatorPolicyRule',
+    'PhabricatorProjectsSearchEngineExtension' => 'PhabricatorSearchEngineExtension',
     'PhabricatorProtocolAdapter' => 'Phobject',
     'PhabricatorPygmentSetupCheck' => 'PhabricatorSetupCheck',
     'PhabricatorQuery' => 'Phobject',
@@ -7459,6 +7462,7 @@ phutil_register_library_map(array(
     'PhabricatorSubscriptionsListController' => 'PhabricatorController',
     'PhabricatorSubscriptionsRemoveSelfHeraldAction' => 'PhabricatorSubscriptionsHeraldAction',
     'PhabricatorSubscriptionsRemoveSubscribersHeraldAction' => 'PhabricatorSubscriptionsHeraldAction',
+    'PhabricatorSubscriptionsSearchEngineExtension' => 'PhabricatorSearchEngineExtension',
     'PhabricatorSubscriptionsSubscribeEmailCommand' => 'MetaMTAEmailTransactionCommand',
     'PhabricatorSubscriptionsSubscribersPolicyRule' => 'PhabricatorPolicyRule',
     'PhabricatorSubscriptionsTransactionController' => 'PhabricatorController',

src/applications/project/engineextension/PhabricatorProjectsSearchEngineExtension.php

@@ -0,0 +1,51 @@
+<?php
+
+final class PhabricatorProjectsSearchEngineExtension
+  extends PhabricatorSearchEngineExtension {
+
+  const EXTENSIONKEY = 'projects';
+
+  public function isExtensionEnabled() {
+    return PhabricatorApplication::isClassInstalled(
+      'PhabricatorProjectApplication');
+  }
+
+  public function getExtensionName() {
+    return pht('Support for Projects');
+  }
+
+  public function getExtensionOrder() {
+    return 2000;
+  }
+
+  public function supportsObject($object) {
+    return ($object instanceof PhabricatorProjectInterface);
+  }
+
+  public function applyConstraintsToQuery(
+    $object,
+    $query,
+    PhabricatorSavedQuery $saved,
+    array $map) {
+
+    if (!empty($map['projectPHIDs'])) {
+      $query->withEdgeLogicConstraints(
+        PhabricatorProjectObjectHasProjectEdgeType::EDGECONST,
+        $map['projectPHIDs']);
+    }
+  }
+
+  public function getSearchFields($object) {
+    $fields = array();
+
+    $fields[] = id(new PhabricatorProjectSearchField())
+      ->setKey('projectPHIDs')
+      ->setConduitKey('projects')
+      ->setAliases(array('project', 'projects'))
+      ->setLabel(pht('Projects'));
+
+    return $fields;
+  }
+
+
+}

src/applications/search/engine/PhabricatorApplicationSearchEngine.php

@@ -19,7 +19,6 @@ abstract class PhabricatorApplicationSearchEngine extends Phobject {
   private $application;
   private $viewer;
   private $errors = array();
-  private $customFields = false;
   private $request;
   private $context;
   private $controller;
@@ -164,35 +163,9 @@ abstract class PhabricatorApplicationSearchEngine extends Phobject {
       return $query;
     }
 
-    if ($object instanceof PhabricatorSubscribableInterface) {
+    $extensions = $this->getEngineExtensions();
-      if (!empty($map['subscriberPHIDs'])) {
+    foreach ($extensions as $extension) {
-        $query->withEdgeLogicPHIDs(
+      $extension->applyConstraintsToQuery($object, $query, $saved, $map);
-          PhabricatorObjectHasSubscriberEdgeType::EDGECONST,
-          PhabricatorQueryConstraint::OPERATOR_OR,
-          $map['subscriberPHIDs']);
-      }
-    }
-
-    if ($object instanceof PhabricatorProjectInterface) {
-      if (!empty($map['projectPHIDs'])) {
-        $query->withEdgeLogicConstraints(
-          PhabricatorProjectObjectHasProjectEdgeType::EDGECONST,
-          $map['projectPHIDs']);
-      }
-    }
-
-    if ($object instanceof PhabricatorSpacesInterface) {
-      if (!empty($map['spacePHIDs'])) {
-        $query->withSpacePHIDs($map['spacePHIDs']);
-      } else {
-        // If the user doesn't search for objects in specific spaces, we
-        // default to "all active spaces you have permission to view".
-        $query->withSpaceIsArchived(false);
-      }
-    }
-
-    if ($object instanceof PhabricatorCustomFieldInterface) {
-      $this->applyCustomFieldsToQuery($query, $saved);
     }
 
     $order = $saved->getParameter('order');
@@ -272,34 +245,15 @@ abstract class PhabricatorApplicationSearchEngine extends Phobject {
 
     $object = $this->newResultObject();
     if ($object) {
-      if ($object instanceof PhabricatorSubscribableInterface) {
+      $extensions = $this->getEngineExtensions();
-        $fields[] = id(new PhabricatorSearchSubscribersField())
+      foreach ($extensions as $extension) {
-          ->setLabel(pht('Subscribers'))
+        $extension_fields = $extension->getSearchFields($object);
-          ->setKey('subscriberPHIDs')
+        foreach ($extension_fields as $extension_field) {
-          ->setAliases(array('subscriber', 'subscribers'));
+          $fields[] = $extension_field;
-      }
-
-      if ($object instanceof PhabricatorProjectInterface) {
-        $fields[] = id(new PhabricatorProjectSearchField())
-          ->setKey('projectPHIDs')
-          ->setAliases(array('project', 'projects'))
-          ->setLabel(pht('Projects'));
-      }
-
-      if ($object instanceof PhabricatorSpacesInterface) {
-        if (PhabricatorSpacesNamespaceQuery::getSpacesExist()) {
-          $fields[] = id(new PhabricatorSpacesSearchField())
-            ->setKey('spacePHIDs')
-            ->setAliases(array('space', 'spaces'))
-            ->setLabel(pht('Spaces'));
         }
       }
     }
 
-    foreach ($this->buildCustomFieldSearchFields() as $custom_field) {
-      $fields[] = $custom_field;
-    }
-
     $query = $this->newQuery();
     if ($query && $this->shouldShowOrderField()) {
       $orders = $query->getBuiltinOrders();
@@ -1089,89 +1043,6 @@ abstract class PhabricatorApplicationSearchEngine extends Phobject {
 /* -(  Application Search  )------------------------------------------------- */
 
 
-  /**
-   * Retrieve an object to use to define custom fields for this search.
-   *
-   * To integrate with custom fields, subclasses should override this method
-   * and return an instance of the application object which implements
-   * @{interface:PhabricatorCustomFieldInterface}.
-   *
-   * @return PhabricatorCustomFieldInterface|null Object with custom fields.
-   * @task appsearch
-   */
-  public function getCustomFieldObject() {
-    $object = $this->newResultObject();
-    if ($object instanceof PhabricatorCustomFieldInterface) {
-      return $object;
-    }
-    return null;
-  }
-
-
-  /**
-   * Get the custom fields for this search.
-   *
-   * @return PhabricatorCustomFieldList|null Custom fields, if this search
-   *   supports custom fields.
-   * @task appsearch
-   */
-  public function getCustomFieldList() {
-    if ($this->customFields === false) {
-      $object = $this->getCustomFieldObject();
-      if ($object) {
-        $fields = PhabricatorCustomField::getObjectFields(
-          $object,
-          PhabricatorCustomField::ROLE_APPLICATIONSEARCH);
-        $fields->setViewer($this->requireViewer());
-      } else {
-        $fields = null;
-      }
-      $this->customFields = $fields;
-    }
-    return $this->customFields;
-  }
-
-
-  /**
-   * Applies data from a saved query to an executable query.
-   *
-   * @param PhabricatorCursorPagedPolicyAwareQuery Query to constrain.
-   * @param PhabricatorSavedQuery Saved query to read.
-   * @return void
-   */
-  protected function applyCustomFieldsToQuery(
-    PhabricatorCursorPagedPolicyAwareQuery $query,
-    PhabricatorSavedQuery $saved) {
-
-    $list = $this->getCustomFieldList();
-    if (!$list) {
-      return;
-    }
-
-    foreach ($list->getFields() as $field) {
-      $value = $field->applyApplicationSearchConstraintToQuery(
-        $this,
-        $query,
-        $saved->getParameter('custom:'.$field->getFieldIndex()));
-    }
-  }
-
-  private function buildCustomFieldSearchFields() {
-    $list = $this->getCustomFieldList();
-    if (!$list) {
-      return array();
-    }
-
-    $fields = array();
-    foreach ($list->getFields() as $field) {
-      $fields[] = id(new PhabricatorSearchCustomFieldProxyField())
-        ->setSearchEngine($this)
-        ->setCustomField($field);
-    }
-
-    return $fields;
-  }
-
   public function getSearchFieldsForConduit() {
     $standard_fields = $this->buildSearchFields();
 
@@ -1302,24 +1173,37 @@ abstract class PhabricatorApplicationSearchEngine extends Phobject {
     return $specifications;
   }
 
-  private function getConduitFieldExtensions() {
+  private function getEngineExtensions() {
     $extensions = PhabricatorSearchEngineExtension::getAllEnabledExtensions();
-    $object = $this->newQuery()->newResultObject();
 
-    $field_extensions = array();
     foreach ($extensions as $key => $extension) {
-      $extension->setViewer($this->requireViewer());
+      $extension
+        ->setViewer($this->requireViewer())
+        ->setSearchEngine($this);
+    }
 
+    $object = $this->newResultObject();
+    foreach ($extensions as $key => $extension) {
       if (!$extension->supportsObject($object)) {
-        continue;
+        unset($extensions[$key]);
-      }
-
-      if ($extension->getFieldSpecificationsForConduit($object)) {
-        $field_extensions[$key] = $extension;
       }
     }
 
-    return $field_extensions;
+    return $extensions;
+  }
+
+
+  private function getConduitFieldExtensions() {
+    $extensions = $this->getEngineExtensions();
+    $object = $this->newResultObject();
+
+    foreach ($extensions as $key => $extension) {
+      if (!$extension->getFieldSpecificationsForConduit($object)) {
+        unset($extensions[$key]);
+      }
+    }
+
+    return $extensions;
   }
 
   private function setAutomaticConstraintsForConduit(

src/applications/search/engineextension/PhabricatorSearchEngineExtension.php

@@ -3,6 +3,7 @@
 abstract class PhabricatorSearchEngineExtension extends Phobject {
 
   private $viewer;
+  private $searchEngine;
 
   final public function getExtensionKey() {
     return $this->getPhobjectClassConstant('EXTENSIONKEY');
@@ -17,10 +18,36 @@ abstract class PhabricatorSearchEngineExtension extends Phobject {
     return $this->viewer;
   }
 
+  final public function setSearchEngine(
+    PhabricatorApplicationSearchEngine $engine) {
+    $this->searchEngine = $engine;
+    return $this;
+  }
+
+  final public function getSearchEngine() {
+    return $this->searchEngine;
+  }
+
   abstract public function isExtensionEnabled();
   abstract public function getExtensionName();
   abstract public function supportsObject($object);
 
+  public function getExtensionOrder() {
+    return 5000;
+  }
+
+  public function getSearchFields($object) {
+    return array();
+  }
+
+  public function applyConstraintsToQuery(
+    $object,
+    $query,
+    PhabricatorSavedQuery $saved,
+    array $map) {
+    return;
+  }
+
   public function getFieldSpecificationsForConduit($object) {
     return array();
   }
@@ -33,6 +60,7 @@ abstract class PhabricatorSearchEngineExtension extends Phobject {
     return id(new PhutilClassMapQuery())
       ->setAncestorClass(__CLASS__)
       ->setUniqueMethod('getExtensionKey')
+      ->setSortMethod('getExtensionOrder')
       ->execute();
   }
 

src/applications/search/engineextension/PhabricatorSearchEngineExtensionModule.php

@@ -19,6 +19,7 @@ final class PhabricatorSearchEngineExtensionModule
     $rows = array();
     foreach ($extensions as $extension) {
       $rows[] = array(
+        $extension->getExtensionOrder(),
         $extension->getExtensionKey(),
         get_class($extension),
         $extension->getExtensionName(),
@@ -31,6 +32,7 @@ final class PhabricatorSearchEngineExtensionModule
     $table = id(new AphrontTableView($rows))
       ->setHeaders(
         array(
+          pht('Order'),
           pht('Key'),
           pht('Class'),
           pht('Name'),
@@ -38,6 +40,7 @@ final class PhabricatorSearchEngineExtensionModule
         ))
       ->setColumnClasses(
         array(
+          null,
           null,
           null,
           'wide pri',

src/applications/spaces/engineextension/PhabricatorSpacesSearchEngineExtension.php

@@ -14,10 +14,43 @@ final class PhabricatorSpacesSearchEngineExtension
     return pht('Support for Spaces');
   }
 
+  public function getExtensionOrder() {
+    return 3000;
+  }
+
   public function supportsObject($object) {
     return ($object instanceof PhabricatorSpacesInterface);
   }
 
+  public function getSearchFields($object) {
+    $fields = array();
+
+    if (PhabricatorSpacesNamespaceQuery::getSpacesExist()) {
+      $fields[] = id(new PhabricatorSpacesSearchField())
+        ->setKey('spacePHIDs')
+        ->setConduitKey('spaces')
+        ->setAliases(array('space', 'spaces'))
+        ->setLabel(pht('Spaces'));
+    }
+
+    return $fields;
+  }
+
+  public function applyConstraintsToQuery(
+    $object,
+    $query,
+    PhabricatorSavedQuery $saved,
+    array $map) {
+
+    if (!empty($map['spacePHIDs'])) {
+      $query->withSpacePHIDs($map['spacePHIDs']);
+    } else {
+      // If the user doesn't search for objects in specific spaces, we
+      // default to "all active spaces you have permission to view".
+      $query->withSpaceIsArchived(false);
+    }
+  }
+
   public function getFieldSpecificationsForConduit($object) {
     return array(
       'spacePHID' => array(

src/applications/subscriptions/engineextension/PhabricatorSubscriptionsEditEngineExtension.php

@@ -34,8 +34,6 @@ final class PhabricatorSubscriptionsEditEngineExtension
       $sub_phids = PhabricatorSubscribersQuery::loadSubscribersForPHID(
         $object_phid);
     } else {
-      // TODO: Allow applications to provide default subscribers? Maniphest
-      // does this at a minimum.
       $sub_phids = array();
     }
 

src/applications/subscriptions/engineextension/PhabricatorSubscriptionsSearchEngineExtension.php

@@ -0,0 +1,52 @@
+<?php
+
+final class PhabricatorSubscriptionsSearchEngineExtension
+  extends PhabricatorSearchEngineExtension {
+
+  const EXTENSIONKEY = 'subscriptions';
+
+  public function isExtensionEnabled() {
+    return PhabricatorApplication::isClassInstalled(
+      'PhabricatorSubscriptionsApplication');
+  }
+
+  public function getExtensionName() {
+    return pht('Support for Subscriptions');
+  }
+
+  public function getExtensionOrder() {
+    return 1000;
+  }
+
+  public function supportsObject($object) {
+    return ($object instanceof PhabricatorSubscribableInterface);
+  }
+
+  public function applyConstraintsToQuery(
+    $object,
+    $query,
+    PhabricatorSavedQuery $saved,
+    array $map) {
+
+    if (!empty($map['subscriberPHIDs'])) {
+      $query->withEdgeLogicPHIDs(
+        PhabricatorObjectHasSubscriberEdgeType::EDGECONST,
+        PhabricatorQueryConstraint::OPERATOR_OR,
+        $map['subscriberPHIDs']);
+    }
+  }
+
+  public function getSearchFields($object) {
+    $fields = array();
+
+    $fields[] = id(new PhabricatorSearchSubscribersField())
+      ->setLabel(pht('Subscribers'))
+      ->setKey('subscriberPHIDs')
+      ->setConduitKey('subscribers')
+      ->setAliases(array('subscriber', 'subscribers'));
+
+    return $fields;
+  }
+
+
+}

src/infrastructure/customfield/engineextension/PhabricatorCustomFieldSearchEngineExtension.php

@@ -17,6 +17,50 @@ final class PhabricatorCustomFieldSearchEngineExtension
     return ($object instanceof PhabricatorCustomFieldInterface);
   }
 
+  public function getExtensionOrder() {
+    return 9000;
+  }
+
+  public function getSearchFields($object) {
+    $engine = $this->getSearchEngine();
+    $custom_fields = $this->getCustomFields($object);
+
+    $fields = array();
+    foreach ($custom_fields as $field) {
+      $fields[] = id(new PhabricatorSearchCustomFieldProxyField())
+        ->setSearchEngine($engine)
+        ->setCustomField($field);
+    }
+
+    return $fields;
+  }
+
+  public function applyConstraintsToQuery(
+    $object,
+    $query,
+    PhabricatorSavedQuery $saved,
+    array $map) {
+
+    $engine = $this->getSearchEngine();
+    $fields = $this->getCustomFields($object);
+
+    foreach ($fields as $field) {
+      $field->applyApplicationSearchConstraintToQuery(
+        $engine,
+        $query,
+        $saved->getParameter('custom:'.$field->getFieldIndex()));
+    }
+  }
+
+  private function getCustomFields($object) {
+    $fields = PhabricatorCustomField::getObjectFields(
+      $object,
+      PhabricatorCustomField::ROLE_APPLICATIONSEARCH);
+    $fields->setViewer($this->getViewer());
+
+    return $fields->getFields();
+  }
+
   public function getFieldSpecificationsForConduit($object) {
     $fields = PhabricatorCustomField::getObjectFields(
       $object,