upload: add new optional argument designating an upload size limit

lib/pleroma/upload.ex

@@ -4,12 +4,21 @@ defmodule Pleroma.Upload do
   @storage_backend Application.get_env(:pleroma, Pleroma.Upload)
                    |> Keyword.fetch!(:uploader)
 
-  def store(%Plug.Upload{} = file, should_dedupe) do
+  def check_file_size(path, nil), do: true
+
+  def check_file_size(path, size_limit) do
+    {:ok, %{size: size}} = File.stat(path)
+    size <= size_limit
+  end
+
+  def store(file, should_dedupe, size_limit \\ nil)
+
+  def store(%Plug.Upload{} = file, should_dedupe, size_limit) do
     content_type = get_content_type(file.path)
 
-    uuid = get_uuid(file, should_dedupe)
+    with uuid <- get_uuid(file, should_dedupe),
-    name = get_name(file, uuid, content_type, should_dedupe)
+         name <- get_name(file, uuid, content_type, should_dedupe),
-
+         true <- check_file_size(file.path, size_limit) do
       strip_exif_data(content_type, file.path)
 
       {:ok, url_path} =
@@ -26,16 +35,18 @@ def store(%Plug.Upload{} = file, should_dedupe) do
         ],
         "name" => name
       }
+    else
+      _e -> nil
+    end
   end
 
-  def store(%{"img" => "data:image/" <> image_data}, should_dedupe) do
+  def store(%{"img" => "data:image/" <> image_data}, should_dedupe, size_limit) do
     parsed = Regex.named_captures(~r/(?<filetype>jpeg|png|gif);base64,(?<data>.*)/, image_data)
     data = Base.decode64!(parsed["data"], ignore: :whitespace)
 
-    tmp_path = tempfile_for_image(data)
+    with tmp_path <- tempfile_for_image(data),
-
+         uuid <- UUID.generate(),
-    uuid = UUID.generate()
+         true <- check_file_size(tmp_path, size_limit) do
-
       content_type = get_content_type(tmp_path)
       strip_exif_data(content_type, tmp_path)
 
@@ -46,7 +57,8 @@ def store(%{"img" => "data:image/" <> image_data}, should_dedupe) do
           content_type
         )
 
-    {:ok, url_path} = @storage_backend.put_file(name, uuid, tmp_path, content_type, should_dedupe)
+      {:ok, url_path} =
+        @storage_backend.put_file(name, uuid, tmp_path, content_type, should_dedupe)
 
       %{
         "type" => "Image",
@@ -59,6 +71,9 @@ def store(%{"img" => "data:image/" <> image_data}, should_dedupe) do
         ],
         "name" => name
       }
+    else
+      _e -> nil
+    end
   end
 
   @doc """