From afa4b98c4a8b1a78d976b8e4d106517ca3ee9d52 Mon Sep 17 00:00:00 2001
From: Toby Zerner <toby.zerner@gmail.com>
Date: Sat, 28 Mar 2015 12:13:19 +1030
Subject: [PATCH] Only get posts with registered types.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

This is so that if an extension adds a post type, and the database gets
populated with posts of that type, but then if the extension is
disabled, we wouldn’t want those posts to display because we would have
no knowledge about how to deal with/render them.
---
 src/Core/Models/Discussion.php           |  2 +-
 src/Core/Models/Post.php                 | 19 ++++++++
 src/Core/Models/RegisteredTypesScope.php | 55 ++++++++++++++++++++++++
 3 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 src/Core/Models/RegisteredTypesScope.php

diff --git a/src/Core/Models/Discussion.php b/src/Core/Models/Discussion.php
index a6a7aaa34..4211e755c 100755
--- a/src/Core/Models/Discussion.php
+++ b/src/Core/Models/Discussion.php
@@ -68,7 +68,7 @@ class Discussion extends Model
         static::deleted(function ($discussion) {
             $discussion->raise(new DiscussionWasDeleted($discussion));
 
-            $discussion->posts()->delete();
+            $discussion->posts()->allTypes()->delete();
             $discussion->readers()->detach();
         });
     }
diff --git a/src/Core/Models/Post.php b/src/Core/Models/Post.php
index c387331aa..1a48bc71b 100755
--- a/src/Core/Models/Post.php
+++ b/src/Core/Models/Post.php
@@ -65,6 +65,8 @@ class Post extends Model
         static::deleted(function ($post) {
             $post->raise(new PostWasDeleted($post));
         });
+
+        static::addGlobalScope(new RegisteredTypesScope);
     }
 
     /**
@@ -119,6 +121,18 @@ class Post extends Model
         return array_map('intval', $query->get(['id'])->fetch('id')->all());
     }
 
+    /**
+     * Get all posts, regardless of their type, by removing the
+     * `RegisteredTypesScope` global scope constraints applied on this model.
+     *
+     * @param \Illuminate\Database\Eloquent\Builder $query
+     * @return \Illuminate\Database\Eloquent\Builder
+     */
+    public function scopeAllTypes($query)
+    {
+        return $this->removeGlobalScopes($query);
+    }
+
     /**
      * Create a new model instance according to the post's type.
      *
@@ -155,4 +169,9 @@ class Post extends Model
     {
         static::$types[$type] = $class;
     }
+
+    public static function getTypes()
+    {
+        return static::$types;
+    }
 }
diff --git a/src/Core/Models/RegisteredTypesScope.php b/src/Core/Models/RegisteredTypesScope.php
new file mode 100644
index 000000000..007e08960
--- /dev/null
+++ b/src/Core/Models/RegisteredTypesScope.php
@@ -0,0 +1,55 @@
+<?php namespace Flarum\Core\Models;
+
+use Illuminate\Database\Eloquent\ScopeInterface;
+use Illuminate\Database\Eloquent\Builder;
+use Illuminate\Database\Eloquent\Model;
+
+class RegisteredTypesScope implements ScopeInterface
+{
+    /**
+     * Apply the scope to a given Eloquent query builder.
+     *
+     * @param  \Illuminate\Database\Eloquent\Builder  $builder
+     * @param  \Illuminate\Database\Eloquent\Model  $model
+     * @return void
+     */
+    public function apply(Builder $builder, Model $model)
+    {
+        $builder->whereIn('type', array_keys($model::getTypes()));
+    }
+
+    /**
+     * Remove the scope from the given Eloquent query builder.
+     *
+     * @param  \Illuminate\Database\Eloquent\Builder  $builder
+     * @param  \Illuminate\Database\Eloquent\Model  $model
+     * @return void
+     */
+    public function remove(Builder $builder, Model $model)
+    {
+        $query = $builder->getQuery();
+
+        foreach ((array) $query->wheres as $key => $where)
+        {
+            if ($this->isTypeConstraint($where))
+            {
+                unset($query->wheres[$key]);
+
+                $query->wheres = array_values($query->wheres);
+            }
+        }
+    }
+
+    /**
+     * Determine if the given where clause is a type constraint.
+     *
+     * @param  array   $where
+     * @param  string  $column
+     * @return bool
+     */
+    protected function isTypeConstraint(array $where)
+    {
+        return $where['type'] == 'In' && $where['column'] == 'type';
+    }
+
+}