X-Git-Url: https://git.squeep.com/?a=blobdiff_plain;f=lib%2Fpleroma%2Fpagination.ex;h=d43a96cd2ee4bcfef30d9570722c59e7fd730b89;hb=027714b519cca63ac943369d0bcc9534ba448a80;hp=7c864deef8feb05b79d8001bba03389c94e77294;hpb=1b4c4d29a3bff0d316162b6a71b1e7ca0ff12647;p=akkoma

diff --git a/lib/pleroma/pagination.ex b/lib/pleroma/pagination.ex
index 7c864deef..d43a96cd2 100644
--- a/lib/pleroma/pagination.ex
+++ b/lib/pleroma/pagination.ex
@@ -1,3 +1,7 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2020 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
 defmodule Pleroma.Pagination do
   @moduledoc """
   Implements Mastodon-compatible pagination.
@@ -8,24 +12,72 @@ defmodule Pleroma.Pagination do
 
   alias Pleroma.Repo
 
+  @type type :: :keyset | :offset
+
   @default_limit 20
+  @max_limit 40
+  @page_keys ["max_id", "min_id", "limit", "since_id", "order"]
+
+  def page_keys, do: @page_keys
+
+  @spec fetch_paginated(Ecto.Query.t(), map(), type(), atom() | nil) :: [Ecto.Schema.t()]
+  def fetch_paginated(query, params, type \\ :keyset, table_binding \\ nil)
+
+  def fetch_paginated(query, %{"total" => true} = params, :keyset, table_binding) do
+    total = Repo.aggregate(query, :count, :id)
+
+    %{
+      total: total,
+      items: fetch_paginated(query, Map.drop(params, ["total"]), :keyset, table_binding)
+    }
+  end
 
-  def fetch_paginated(query, params) do
+  def fetch_paginated(query, params, :keyset, table_binding) do
     options = cast_params(params)
 
     query
-    |> paginate(options)
+    |> paginate(options, :keyset, table_binding)
     |> Repo.all()
     |> enforce_order(options)
   end
 
-  def paginate(query, options) do
+  def fetch_paginated(query, %{"total" => true} = params, :offset, table_binding) do
+    total =
+      query
+      |> Ecto.Query.exclude(:left_join)
+      |> Repo.aggregate(:count, :id)
+
+    %{
+      total: total,
+      items: fetch_paginated(query, Map.drop(params, ["total"]), :offset, table_binding)
+    }
+  end
+
+  def fetch_paginated(query, params, :offset, table_binding) do
+    options = cast_params(params)
+
     query
-    |> restrict(:min_id, options)
-    |> restrict(:since_id, options)
-    |> restrict(:max_id, options)
-    |> restrict(:order, options)
-    |> restrict(:limit, options)
+    |> paginate(options, :offset, table_binding)
+    |> Repo.all()
+  end
+
+  @spec paginate(Ecto.Query.t(), map(), type(), atom() | nil) :: [Ecto.Schema.t()]
+  def paginate(query, options, method \\ :keyset, table_binding \\ nil)
+
+  def paginate(query, options, :keyset, table_binding) do
+    query
+    |> restrict(:min_id, options, table_binding)
+    |> restrict(:since_id, options, table_binding)
+    |> restrict(:max_id, options, table_binding)
+    |> restrict(:order, options, table_binding)
+    |> restrict(:limit, options, table_binding)
+  end
+
+  def paginate(query, options, :offset, table_binding) do
+    query
+    |> restrict(:order, options, table_binding)
+    |> restrict(:offset, options, table_binding)
+    |> restrict(:limit, options, table_binding)
   end
 
   defp cast_params(params) do
@@ -33,41 +85,67 @@ defmodule Pleroma.Pagination do
       min_id: :string,
       since_id: :string,
       max_id: :string,
-      limit: :integer
+      offset: :integer,
+      limit: :integer,
+      skip_order: :boolean
     }
 
+    params =
+      Enum.reduce(params, %{}, fn
+        {key, _value}, acc when is_atom(key) -> Map.drop(acc, [key])
+        {key, value}, acc -> Map.put(acc, key, value)
+      end)
+
     changeset = cast({%{}, param_types}, params, Map.keys(param_types))
     changeset.changes
   end
 
-  defp restrict(query, :min_id, %{min_id: min_id}) do
-    where(query, [q], q.id > ^min_id)
+  defp restrict(query, :min_id, %{min_id: min_id}, table_binding) do
+    where(query, [{q, table_position(query, table_binding)}], q.id > ^min_id)
+  end
+
+  defp restrict(query, :since_id, %{since_id: since_id}, table_binding) do
+    where(query, [{q, table_position(query, table_binding)}], q.id > ^since_id)
   end
 
-  defp restrict(query, :since_id, %{since_id: since_id}) do
-    where(query, [q], q.id > ^since_id)
+  defp restrict(query, :max_id, %{max_id: max_id}, table_binding) do
+    where(query, [{q, table_position(query, table_binding)}], q.id < ^max_id)
   end
 
-  defp restrict(query, :max_id, %{max_id: max_id}) do
-    where(query, [q], q.id < ^max_id)
+  defp restrict(query, :order, %{skip_order: true}, _), do: query
+
+  defp restrict(query, :order, %{min_id: _}, table_binding) do
+    order_by(
+      query,
+      [{u, table_position(query, table_binding)}],
+      fragment("? asc nulls last", u.id)
+    )
   end
 
-  defp restrict(query, :order, %{min_id: _}) do
-    order_by(query, [u], fragment("? asc nulls last", u.id))
+  defp restrict(query, :order, _options, table_binding) do
+    order_by(
+      query,
+      [{u, table_position(query, table_binding)}],
+      fragment("? desc nulls last", u.id)
+    )
   end
 
-  defp restrict(query, :order, _options) do
-    order_by(query, [u], fragment("? desc nulls last", u.id))
+  defp restrict(query, :offset, %{offset: offset}, _table_binding) do
+    offset(query, ^offset)
   end
 
-  defp restrict(query, :limit, options) do
-    limit = Map.get(options, :limit, @default_limit)
+  defp restrict(query, :limit, options, _table_binding) do
+    limit =
+      case Map.get(options, :limit, @default_limit) do
+        limit when limit < @max_limit -> limit
+        _ -> @max_limit
+      end
 
     query
     |> limit(^limit)
   end
 
-  defp restrict(query, _, _), do: query
+  defp restrict(query, _, _, _), do: query
 
   defp enforce_order(result, %{min_id: _}) do
     result
@@ -75,4 +153,10 @@ defmodule Pleroma.Pagination do
   end
 
   defp enforce_order(result, _), do: result
+
+  defp table_position(%Ecto.Query{} = query, binding_name) do
+    Map.get(query.aliases, binding_name, 0)
+  end
+
+  defp table_position(_, _), do: 0
 end