FEATURE: Create upload_references table (#16146)

This table holds associations between uploads and other models. This can be used to prevent removing uploads that are still in use.

* DEV: Create upload_references
* DEV: Use UploadReference instead of PostUpload
* DEV: Use UploadReference for SiteSetting
* DEV: Use UploadReference for Badge
* DEV: Use UploadReference for Category
* DEV: Use UploadReference for CustomEmoji
* DEV: Use UploadReference for Group
* DEV: Use UploadReference for ThemeField
* DEV: Use UploadReference for ThemeSetting
* DEV: Use UploadReference for User
* DEV: Use UploadReference for UserAvatar
* DEV: Use UploadReference for UserExport
* DEV: Use UploadReference for UserProfile
* DEV: Add method to extract uploads from raw text
* DEV: Use UploadReference for Draft
* DEV: Use UploadReference for ReviewableQueuedPost
* DEV: Use UploadReference for UserProfile's bio_raw
* DEV: Do not copy user uploads to upload references
* DEV: Copy post uploads again after deploy
* DEV: Use created_at and updated_at from uploads table
* FIX: Check if upload site setting is empty
* DEV: Copy user uploads to upload references
* DEV: Make upload extraction less strict

app/models/upload.rb

@@ -20,13 +20,11 @@ class Upload < ActiveRecord::Base
     Post.unscoped { super }
   end
 
-  has_many :post_uploads, dependent: :destroy
-  has_many :posts, through: :post_uploads
-
   has_many :post_hotlinked_media, dependent: :destroy, class_name: "PostHotlinkedMedia"
-
   has_many :optimized_images, dependent: :destroy
   has_many :user_uploads, dependent: :destroy
+  has_many :upload_references, dependent: :destroy
+  has_many :posts, through: :upload_references, source: :target, source_type: 'Post'
   has_many :topic_thumbnails
 
   attr_accessor :for_group_message
@@ -87,43 +85,9 @@ class Upload < ActiveRecord::Base
   end
 
   def self.with_no_non_post_relations
-    scope = self
-      .joins(<<~SQL)
-        LEFT JOIN site_settings ss
-        ON NULLIF(ss.value, '')::integer = uploads.id
-        AND ss.data_type = #{SiteSettings::TypeSupervisor.types[:upload].to_i}
-      SQL
-      .where("ss.value IS NULL")
-      .joins("LEFT JOIN users u ON u.uploaded_avatar_id = uploads.id")
-      .where("u.uploaded_avatar_id IS NULL")
-      .joins("LEFT JOIN user_avatars ua ON ua.gravatar_upload_id = uploads.id OR ua.custom_upload_id = uploads.id")
-      .where("ua.gravatar_upload_id IS NULL AND ua.custom_upload_id IS NULL")
-      .joins("LEFT JOIN user_profiles up ON up.profile_background_upload_id = uploads.id OR up.card_background_upload_id = uploads.id")
-      .where("up.profile_background_upload_id IS NULL AND up.card_background_upload_id IS NULL")
-      .joins("LEFT JOIN categories c ON c.uploaded_logo_id = uploads.id OR c.uploaded_background_id = uploads.id")
-      .where("c.uploaded_logo_id IS NULL AND c.uploaded_background_id IS NULL")
-      .joins("LEFT JOIN custom_emojis ce ON ce.upload_id = uploads.id")
-      .where("ce.upload_id IS NULL")
-      .joins("LEFT JOIN theme_fields tf ON tf.upload_id = uploads.id")
-      .where("tf.upload_id IS NULL")
-      .joins("LEFT JOIN user_exports ue ON ue.upload_id = uploads.id")
-      .where("ue.upload_id IS NULL")
-      .joins("LEFT JOIN groups g ON g.flair_upload_id = uploads.id")
-      .where("g.flair_upload_id IS NULL")
-      .joins("LEFT JOIN badges b ON b.image_upload_id = uploads.id")
-      .where("b.image_upload_id IS NULL")
-      .joins(<<~SQL)
-        LEFT JOIN theme_settings ts
-        ON NULLIF(ts.value, '')::integer = uploads.id
-        AND ts.data_type = #{ThemeSetting.types[:upload].to_i}
-      SQL
-      .where("ts.value IS NULL")
-
-    if SiteSetting.selectable_avatars.present?
-      scope = scope.where.not(id: SiteSetting.selectable_avatars.map(&:id))
-    end
-
-    scope
+    self
+      .joins("LEFT JOIN upload_references ur ON ur.upload_id = uploads.id AND ur.target_type != 'Post'")
+      .where("ur.upload_id IS NULL")
   end
 
   def to_s
@@ -542,6 +506,22 @@ class Upload < ActiveRecord::Base
     problems
   end
 
+  def self.extract_upload_ids(raw)
+    return [] if raw.blank?
+
+    sha1s = []
+
+    raw.scan(/\/(\h{40})/).each do |match|
+      sha1s << match[0]
+    end
+
+    raw.scan(/\/([a-zA-Z0-9]{27})/).each do |match|
+      sha1s << Upload.sha1_from_base62_encoded(match[0])
+    end
+
+    Upload.where(sha1: sha1s.uniq).pluck(:id)
+  end
+
   private
 
   def short_url_basename