Support export engine extensions and implement an extension for custom fields

Summary:
Depends on D18953. Ref T13049. Allow applications and infrastructure to supplement exportable fields for objects.

Then, implement an extension for custom fields. Only a couple field types (int, string) are supported for now.

Test Plan: Added some custom fields to Users, populated them, exported users. Saw custom fields in the export.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13049

Differential Revision: https://secure.phabricator.com/D18954

src/__phutil_library_map__.php

@@ -2583,6 +2583,7 @@ phutil_register_library_map(array(
     'PhabricatorCustomFieldEditEngineExtension' => 'infrastructure/customfield/engineextension/PhabricatorCustomFieldEditEngineExtension.php',
     'PhabricatorCustomFieldEditField' => 'infrastructure/customfield/editor/PhabricatorCustomFieldEditField.php',
     'PhabricatorCustomFieldEditType' => 'infrastructure/customfield/editor/PhabricatorCustomFieldEditType.php',
+    'PhabricatorCustomFieldExportEngineExtension' => 'infrastructure/export/PhabricatorCustomFieldExportEngineExtension.php',
     'PhabricatorCustomFieldFulltextEngineExtension' => 'infrastructure/customfield/engineextension/PhabricatorCustomFieldFulltextEngineExtension.php',
     'PhabricatorCustomFieldHeraldAction' => 'infrastructure/customfield/herald/PhabricatorCustomFieldHeraldAction.php',
     'PhabricatorCustomFieldHeraldActionGroup' => 'infrastructure/customfield/herald/PhabricatorCustomFieldHeraldActionGroup.php',
@@ -2847,6 +2848,7 @@ phutil_register_library_map(array(
     'PhabricatorEventType' => 'infrastructure/events/constant/PhabricatorEventType.php',
     'PhabricatorExampleEventListener' => 'infrastructure/events/PhabricatorExampleEventListener.php',
     'PhabricatorExecFutureFileUploadSource' => 'applications/files/uploadsource/PhabricatorExecFutureFileUploadSource.php',
+    'PhabricatorExportEngineExtension' => 'infrastructure/export/PhabricatorExportEngineExtension.php',
     'PhabricatorExportField' => 'infrastructure/export/PhabricatorExportField.php',
     'PhabricatorExportFormat' => 'infrastructure/export/PhabricatorExportFormat.php',
     'PhabricatorExtendedPolicyInterface' => 'applications/policy/interface/PhabricatorExtendedPolicyInterface.php',
@@ -7991,6 +7993,7 @@ phutil_register_library_map(array(
     'PhabricatorCustomFieldEditEngineExtension' => 'PhabricatorEditEngineExtension',
     'PhabricatorCustomFieldEditField' => 'PhabricatorEditField',
     'PhabricatorCustomFieldEditType' => 'PhabricatorEditType',
+    'PhabricatorCustomFieldExportEngineExtension' => 'PhabricatorExportEngineExtension',
     'PhabricatorCustomFieldFulltextEngineExtension' => 'PhabricatorFulltextEngineExtension',
     'PhabricatorCustomFieldHeraldAction' => 'HeraldAction',
     'PhabricatorCustomFieldHeraldActionGroup' => 'HeraldActionGroup',
@@ -8280,6 +8283,7 @@ phutil_register_library_map(array(
     'PhabricatorEventType' => 'PhutilEventType',
     'PhabricatorExampleEventListener' => 'PhabricatorEventListener',
     'PhabricatorExecFutureFileUploadSource' => 'PhabricatorFileUploadSource',
+    'PhabricatorExportEngineExtension' => 'Phobject',
     'PhabricatorExportField' => 'Phobject',
     'PhabricatorExportFormat' => 'Phobject',
     'PhabricatorExtendingPhabricatorConfigOptions' => 'PhabricatorApplicationConfigOptions',

src/applications/search/engine/PhabricatorApplicationSearchEngine.php

@@ -1483,6 +1483,26 @@ abstract class PhabricatorApplicationSearchEngine extends Phobject {
       $fields[$key] = $export_field;
     }
 
+    $extensions = $this->newExportExtensions();
+    foreach ($extensions as $extension) {
+      $extension_fields = $extension->newExportFields();
+      foreach ($extension_fields as $extension_field) {
+        $key = $extension_field->getKey();
+
+        if (isset($fields[$key])) {
+          throw new Exception(
+            pht(
+              'Export engine extension ("%s") defines an export field with '.
+              'a key ("%s") that collides with another field. Each field '.
+              'must have a unique key.',
+              get_class($extension_field),
+              $key));
+        }
+
+        $fields[$key] = $extension_field;
+      }
+    }
+
     return $fields;
   }
 
@@ -1514,6 +1534,25 @@ abstract class PhabricatorApplicationSearchEngine extends Phobject {
       $maps[$ii] += $export_data[$ii];
     }
 
+    $extensions = $this->newExportExtensions();
+    foreach ($extensions as $extension) {
+      $extension_data = $extension->newExportData($objects);
+      $extension_data = array_values($extension_data);
+      if (count($export_data) !== count($objects)) {
+        throw new Exception(
+          pht(
+            'Export engine extension ("%s") exported the wrong number of '.
+            'objects, expected %s but got %s.',
+            get_class($extension),
+            phutil_count($objects),
+            phutil_count($export_data)));
+      }
+
+      for ($ii = 0; $ii < $n; $ii++) {
+        $maps[$ii] += $extension_data[$ii];
+      }
+    }
+
     return $maps;
   }
 
@@ -1525,4 +1564,23 @@ abstract class PhabricatorApplicationSearchEngine extends Phobject {
     throw new PhutilMethodNotImplementedException();
   }
 
+  private function newExportExtensions() {
+    $object = $this->newResultObject();
+    $viewer = $this->requireViewer();
+
+    $extensions = PhabricatorExportEngineExtension::getAllExtensions();
+
+    $supported = array();
+    foreach ($extensions as $extension) {
+      $extension = clone $extension;
+      $extension->setViewer($viewer);
+
+      if ($extension->supportsObject($object)) {
+        $supported[] = $extension;
+      }
+    }
+
+    return $supported;
+  }
+
 }

src/infrastructure/customfield/field/PhabricatorCustomField.php

@@ -35,6 +35,7 @@ abstract class PhabricatorCustomField extends Phobject {
   const ROLE_HERALD                   = 'herald';
   const ROLE_EDITENGINE = 'EditEngine';
   const ROLE_HERALDACTION = 'herald.action';
+  const ROLE_EXPORT = 'export';
 
 
 /* -(  Building Applications with Custom Fields  )--------------------------- */
@@ -299,6 +300,8 @@ abstract class PhabricatorCustomField extends Phobject {
       case self::ROLE_EDITENGINE:
         return $this->shouldAppearInEditView() ||
                $this->shouldAppearInEditEngine();
+      case self::ROLE_EXPORT:
+        return $this->shouldAppearInDataExport();
       case self::ROLE_DEFAULT:
         return true;
       default:
@@ -1362,6 +1365,46 @@ abstract class PhabricatorCustomField extends Phobject {
   }
 
 
+/* -(  Data Export  )-------------------------------------------------------- */
+
+
+  public function shouldAppearInDataExport() {
+    if ($this->proxy) {
+      return $this->proxy->shouldAppearInDataExport();
+    }
+
+    try {
+      $this->newExportFieldType();
+      return true;
+    } catch (PhabricatorCustomFieldImplementationIncompleteException $ex) {
+      return false;
+    }
+  }
+
+  public function newExportField() {
+    if ($this->proxy) {
+      return $this->proxy->newExportField();
+    }
+
+    return $this->newExportFieldType()
+      ->setLabel($this->getFieldName());
+  }
+
+  public function newExportData() {
+    if ($this->proxy) {
+      return $this->proxy->newExportData();
+    }
+    throw new PhabricatorCustomFieldImplementationIncompleteException($this);
+  }
+
+  protected function newExportFieldType() {
+    if ($this->proxy) {
+      return $this->proxy->newExportFieldType();
+    }
+    throw new PhabricatorCustomFieldImplementationIncompleteException($this);
+  }
+
+
 /* -(  Conduit  )------------------------------------------------------------ */
 
 

src/infrastructure/customfield/standard/PhabricatorStandardCustomField.php

@@ -496,5 +496,8 @@ abstract class PhabricatorStandardCustomField
     return $this->getFieldValue();
   }
 
+  public function newExportData() {
+    return $this->getFieldValue();
+  }
 
 }

src/infrastructure/customfield/standard/PhabricatorStandardCustomFieldInt.php

@@ -124,4 +124,8 @@ final class PhabricatorStandardCustomFieldInt
     return new ConduitIntParameterType();
   }
 
+  protected function newExportFieldType() {
+    return new PhabricatorIntExportField();
+  }
+
 }

src/infrastructure/customfield/standard/PhabricatorStandardCustomFieldText.php

@@ -76,4 +76,8 @@ final class PhabricatorStandardCustomFieldText
     return new ConduitStringParameterType();
   }
 
+  protected function newExportFieldType() {
+    return new PhabricatorStringExportField();
+  }
+
 }

src/infrastructure/export/PhabricatorCustomFieldExportEngineExtension.php

@@ -0,0 +1,86 @@
+<?php
+
+final class PhabricatorCustomFieldExportEngineExtension
+  extends PhabricatorExportEngineExtension {
+
+  const EXTENSIONKEY = 'custom-field';
+
+  private $object;
+
+  public function supportsObject($object) {
+    $this->object = $object;
+    return ($object instanceof PhabricatorCustomFieldInterface);
+  }
+
+  public function newExportFields() {
+    $prototype = $this->object;
+
+    $fields = $this->newCustomFields($prototype);
+
+    $results = array();
+    foreach ($fields as $field) {
+      $field_key = $field->getModernFieldKey();
+
+      $results[] = $field->newExportField()
+         ->setKey($field_key);
+    }
+
+    return $results;
+  }
+
+  public function newExportData(array $objects) {
+    $viewer = $this->getViewer();
+
+    $field_map = array();
+    foreach ($objects as $object) {
+      $object_phid = $object->getPHID();
+
+      $fields = PhabricatorCustomField::getObjectFields(
+        $object,
+        PhabricatorCustomField::ROLE_EXPORT);
+
+      $fields
+        ->setViewer($viewer)
+        ->readFieldsFromObject($object);
+
+      $field_map[$object_phid] = $fields;
+    }
+
+    $all_fields = array();
+    foreach ($field_map as $field_list) {
+      foreach ($field_list->getFields() as $field) {
+        $all_fields[] = $field;
+      }
+    }
+
+    id(new PhabricatorCustomFieldStorageQuery())
+      ->addFields($all_fields)
+      ->execute();
+
+    $results = array();
+    foreach ($objects as $object) {
+      $object_phid = $object->getPHID();
+      $object_fields = $field_map[$object_phid];
+
+      $map = array();
+      foreach ($object_fields->getFields() as $field) {
+        $key = $field->getModernFieldKey();
+        $map[$key] = $field->newExportData();
+      }
+
+      $results[] = $map;
+    }
+
+    return $results;
+  }
+
+  private function newCustomFields($object) {
+    $fields = PhabricatorCustomField::getObjectFields(
+      $object,
+      PhabricatorCustomField::ROLE_EXPORT);
+    $fields->setViewer($this->getViewer());
+
+    return $fields->getFields();
+  }
+
+}

src/infrastructure/export/PhabricatorExportEngineExtension.php

@@ -0,0 +1,31 @@
+<?php
+
+abstract class PhabricatorExportEngineExtension extends Phobject {
+
+  private $viewer;
+
+  final public function getExtensionKey() {
+    return $this->getPhobjectClassConstant('EXTENSIONKEY');
+  }
+
+  final public function setViewer($viewer) {
+    $this->viewer = $viewer;
+    return $this;
+  }
+
+  final public function getViewer() {
+    return $this->viewer;
+  }
+
+  abstract public function supportsObject($object);
+  abstract public function newExportFields();
+  abstract public function newExportData(array $objects);
+
+  final public static function getAllExtensions() {
+    return id(new PhutilClassMapQuery())
+      ->setAncestorClass(__CLASS__)
+      ->setUniqueMethod('getExtensionKey')
+      ->execute();
+  }
+
+}