NEW Linkfield ownership

_config.php

@@ -5,5 +5,4 @@
 
 // Avoid creating global variables
 call_user_func(function () {
-
 });

_config/config.yml

@@ -21,3 +21,7 @@ SilverStripe\CMS\Forms\AnchorSelectorField:
 SilverStripe\LinkField\Form\FormFactory:
   extensions:
     - SilverStripe\LinkField\Extensions\FormFactoryExtension
+
+SilverStripe\ORM\DataObject:
+  extensions:
+    - SilverStripe\LinkField\Extensions\DataObjectExtension

src/Extensions/DataObjectExtension.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace SilverStripe\LinkField\Extensions;
+
+use SilverStripe\ORM\DataExtension;
+use SilverStripe\LinkField\Models\Link;
+use SilverStripe\LinkField\Models\LinkArea;
+
+class DataObjectExtension extends DataExtension
+{
+    public function onAfterWrite(): void
+    {
+        // Using onAfterWrite instead of onBeforeWrite to ensure that $this->owner->ID is not zero when creating new objects
+        parent::onAfterWrite();
+        foreach ($this->owner->hasOne() as $relation => $relationClassName) {
+            $relationField = $relation . 'ID';
+            $relationID = $this->owner->$relationField;
+            if (!$relationID) {
+                continue;
+            }
+            if (!is_a($relationClassName, Link::class, true) && !is_a($relationClassName, LinkArea::class, true)) {
+                continue;
+            }
+            // skip for the has_one:LinkArea relation on Link
+            if (is_a($this->owner, Link::class) && $relation === 'LinkArea') {
+                continue;
+            }
+            $relationObj = $relationClassName::get()->byID($relationID);
+            if ($relationObj === null) {
+                // could throw an Exception here, though not sure how if user would be able to fix it
+                continue;
+            }
+            $doWrite = false;
+            if ($relationObj->OwnerID !== $this->owner->ID) {
+                $relationObj->OwnerID = $this->owner->ID;
+                $doWrite = true;
+            }
+            if ($relationObj->OwnerClassName !== $this->owner->ClassName) {
+                $relationObj->OwnerClassName = $this->owner->ClassName;
+                $doWrite = true;
+            }
+            if ($doWrite) {
+                $relationObj->write();
+            }
+        }
+    }
+}

src/Extensions/LinkObjectExtension.php

@@ -0,0 +1,65 @@
+<?php
+
+namespace SilverStripe\LinkField\Extensions;
+
+use SilverStripe\ORM\DataExtension;
+use SilverStripe\ORM\DataObject;
+
+/**
+ * This is only intended to be added to Link and LinkArea
+ * Implemented as an extension rather than base class so it doesn't create an extra base table that needs to be joined
+ */
+class LinkObjectExtension extends DataExtension
+{
+    private static array $db = [
+        'OwnerID' => 'Int',
+        'OwnerClassName' => 'Varchar',
+    ];
+
+    public function canView($member = null)
+    {
+        return $this->canCheck('canView', $member);
+    }
+
+    public function canCreate($member = null)
+    {
+        return $this->canCheck('canCreate', $member);
+    }
+
+    public function canEdit($member = null)
+    {
+        return $this->canCheck('canEdit', $member);
+    }
+
+    public function canDelete($member = null)
+    {
+        return $this->canCheck('canDelete', $member);
+    }
+
+    private function canCheck(string $canMethod, $member)
+    {
+        if (!$member) {
+            $member = Security::getCurrentUser();
+        }
+        $extended = $this->extendedCan($canMethod, $member);
+        if ($extended !== null) {
+            return $extended;
+        }
+        $owner = $this->getOwningDataObject();
+        if ($owner) {
+            return $owner->$canMethod($member);
+        }
+        return parent::$canMethod($member);
+    }
+
+    private function getOwningDataObject(): ?DataObject
+    {
+        // method is not called getOwner() because of existing Extension::getOwner() method
+        $ownerID = $this->owner->OwnerID;
+        $ownerClassName = $this->owner->OwnerClassName;
+        if ($ownerID === 0 || $ownerClassName === '') {
+            return null;
+        }
+        return $ownerClassName::get()->byID($ownerID);
+    }
+}

src/Models/Link.php

@@ -16,6 +16,9 @@
 use SilverStripe\ORM\DataObject;
 use SilverStripe\ORM\FieldType\DBHTMLText;
 use SilverStripe\View\Requirements;
+use SilverStripe\LinkField\Extensions\LinkObjectExtension;
+use SilverStripe\Versioned\Versioned;
+use SilverStripe\LinkField\Models\LinkArea;
 
 /**
  * A Link Data Object. This class should be a subclass, and you should never directly interact with a plain Link
@@ -33,6 +36,15 @@ class Link extends DataObject implements JsonData, Type
         'OpenInNew' => 'Boolean',
     ];
 
+    private static array $has_one = [
+        'LinkArea' => LinkArea::class
+    ];
+
+    private static array $extensions = [
+        Versioned::class,
+        LinkObjectExtension::class,
+    ];
+
     /**
      * In-memory only property used to change link type
      * This case is relevant for CMS edit form which doesn't use React driven UI

src/Models/LinkArea.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace SilverStripe\LinkField\Models;
+
+use SilverStripe\LinkField\Models\Link;
+use SilverStripe\LinkField\Extensions\LinkObjectExtension;
+use SilverStripe\ORM\DataObject;
+use SilverStripe\Versioned\Versioned;
+
+class LinkArea extends DataObject
+{
+    private static $table_name = 'LinkField_LinkArea';
+
+    private static array $has_many = [
+        'Links' => Link::class,
+    ];
+
+    private static array $owns = [
+        'Links',
+    ];
+
+    private static array $cascade_deletes = [
+        'Links',
+    ];
+
+    private static array $cascade_duplicates = [
+        'Links',
+    ];
+
+    private static array $extensions = [
+        Versioned::class,
+        LinkObjectExtension::class,
+    ];
+}