FollowingRelationship storage & performance optimizations (state turned ecto_enum-driven integer, reorganized indices etc.).

lib/pleroma/following_relationship.ex

@@ -13,7 +13,7 @@ defmodule Pleroma.FollowingRelationship do
   alias Pleroma.User
 
   schema "following_relationships" do
-    field(:state, :string, default: "accept")
+    field(:state, FollowingRelationshipStateEnum, default: :follow_pending)
 
     belongs_to(:follower, User, type: CompatType)
     belongs_to(:following, User, type: CompatType)
@@ -27,6 +27,19 @@ defmodule Pleroma.FollowingRelationship do
     |> put_assoc(:follower, attrs.follower)
     |> put_assoc(:following, attrs.following)
     |> validate_required([:state, :follower, :following])
+    |> unique_constraint(:follower_id,
+      name: :following_relationships_follower_id_following_id_index
+    )
+    |> validate_not_self_relationship()
+  end
+
+  def state_to_enum(state) when is_binary(state) do
+    case state do
+      "pending" -> :follow_pending
+      "accept" -> :follow_accept
+      "reject" -> :follow_reject
+      _ -> raise "State is not convertible to FollowingRelationshipStateEnum: #{state}"
+    end
   end
 
   def get(%User{} = follower, %User{} = following) do
@@ -35,7 +48,7 @@ defmodule Pleroma.FollowingRelationship do
     |> Repo.one()
   end
 
-  def update(follower, following, "reject"), do: unfollow(follower, following)
+  def update(follower, following, :follow_reject), do: unfollow(follower, following)
 
   def update(%User{} = follower, %User{} = following, state) do
     case get(follower, following) do
@@ -50,7 +63,7 @@ defmodule Pleroma.FollowingRelationship do
     end
   end
 
-  def follow(%User{} = follower, %User{} = following, state \\ "accept") do
+  def follow(%User{} = follower, %User{} = following, state \\ :follow_accept) do
     %__MODULE__{}
     |> changeset(%{follower: follower, following: following, state: state})
     |> Repo.insert(on_conflict: :nothing)
@@ -80,7 +93,7 @@ defmodule Pleroma.FollowingRelationship do
   def get_follow_requests(%User{id: id}) do
     __MODULE__
     |> join(:inner, [r], f in assoc(r, :follower))
-    |> where([r], r.state == "pending")
+    |> where([r], r.state == ^:follow_pending)
     |> where([r], r.following_id == ^id)
     |> select([r, f], f)
     |> Repo.all()
@@ -88,7 +101,7 @@ defmodule Pleroma.FollowingRelationship do
 
   def following?(%User{id: follower_id}, %User{id: followed_id}) do
     __MODULE__
-    |> where(follower_id: ^follower_id, following_id: ^followed_id, state: "accept")
+    |> where(follower_id: ^follower_id, following_id: ^followed_id, state: ^:follow_accept)
     |> Repo.exists?()
   end
 
@@ -97,7 +110,7 @@ defmodule Pleroma.FollowingRelationship do
       __MODULE__
       |> join(:inner, [r], u in User, on: r.following_id == u.id)
       |> where([r], r.follower_id == ^user.id)
-      |> where([r], r.state == "accept")
+      |> where([r], r.state == ^:follow_accept)
       |> select([r, u], u.follower_address)
       |> Repo.all()
 
@@ -157,4 +170,22 @@ defmodule Pleroma.FollowingRelationship do
       fr -> fr.follower_id == follower.id and fr.following_id == following.id
     end)
   end
+
+  defp validate_not_self_relationship(%Ecto.Changeset{} = changeset) do
+    changeset
+    |> validate_change(:following_id, fn _, following_id ->
+      if following_id == get_field(changeset, :follower_id) do
+        [target_id: "can't be equal to follower_id"]
+      else
+        []
+      end
+    end)
+    |> validate_change(:follower_id, fn _, follower_id ->
+      if follower_id == get_field(changeset, :following_id) do
+        [source_id: "can't be equal to following_id"]
+      else
+        []
+      end
+    end)
+  end
 end