Make frame and text stream updates implicit (#2451)

lib/livebook_web/live/app_session_live.ex

@@ -410,11 +410,11 @@ defmodule LivebookWeb.AppSessionLive do
         changed_input_ids = Session.Data.changed_input_ids(data)
 
         for {{idx, frame}, cell} <- Notebook.find_frame_outputs(data.notebook, ref) do
+          input_views = input_views_for_cell(cell, data, changed_input_ids)
+
           send_update(LivebookWeb.Output.FrameComponent,
             id: "outputs-#{idx}-output",
-            outputs: frame.outputs,
+            event: {:update, update_type, frame.outputs, input_views}
-            update_type: update_type,
-            input_views: input_views_for_cell(cell, data, changed_input_ids)
           )
         end
 
@@ -432,7 +432,7 @@ defmodule LivebookWeb.AppSessionLive do
                 :markdown -> LivebookWeb.Output.MarkdownComponent
               end
 
-            send_update(module, id: "outputs-#{idx}-output", text: output.text)
+            send_update(module, id: "outputs-#{idx}-output", event: {:append, output.text})
             data_view
 
           _ ->

lib/livebook_web/live/output/frame_component.ex

@@ -7,19 +7,11 @@ defmodule LivebookWeb.Output.FrameComponent do
   end
 
   @impl true
-  def update(assigns, socket) do
+  def update(%{event: {:update, update_type, outputs, input_views}}, socket) do
-    {update_type, assigns} = Map.pop(assigns, :update_type, nil)
+    socket = assign(socket, input_views: input_views)
-    {outputs, assigns} = Map.pop!(assigns, :outputs)
-
-    socket = assign(socket, assigns)
-
-    socket = assign_new(socket, :num_outputs, fn -> length(outputs) end)
 
     socket =
       case update_type do
-        nil ->
-          stream(socket, :outputs, stream_items(outputs))
-
         :replace ->
           socket
           |> assign(num_outputs: length(outputs))
@@ -34,6 +26,17 @@ defmodule LivebookWeb.Output.FrameComponent do
     {:ok, socket}
   end
 
+  def update(assigns, socket) do
+    {outputs, assigns} = Map.pop!(assigns, :outputs)
+
+    socket = assign(socket, assigns)
+
+    socket = assign_new(socket, :num_outputs, fn -> length(outputs) end)
+    socket = stream(socket, :outputs, stream_items(outputs))
+
+    {:ok, socket}
+  end
+
   defp stream_items(outputs) do
     for {idx, output} <- Enum.reverse(outputs) do
       %{id: Integer.to_string(idx), idx: idx, output: output}

lib/livebook_web/live/output/markdown_component.ex

@@ -5,24 +5,34 @@ defmodule LivebookWeb.Output.MarkdownComponent do
   def mount(socket) do
     {:ok,
      socket
-     |> assign(allowed_uri_schemes: Livebook.Config.allowed_uri_schemes())
+     |> assign(allowed_uri_schemes: Livebook.Config.allowed_uri_schemes(), initialized: false)
      |> stream(:chunks, [])}
   end
 
   @impl true
+  def update(%{event: {:append, text}}, socket) do
+    {:ok, append_text(socket, text)}
+  end
+
   def update(assigns, socket) do
     {text, assigns} = Map.pop(assigns, :text)
-
     socket = assign(socket, assigns)
 
-    if text do
+    if socket.assigns.initialized do
-      chunk = %{id: Livebook.Utils.random_long_id(), text: text}
-      {:ok, stream_insert(socket, :chunks, chunk)}
-    else
       {:ok, socket}
+    else
+      {:ok,
+       socket
+       |> append_text(text)
+       |> assign(:initialized, true)}
     end
   end
 
+  defp append_text(socket, text) do
+    chunk = %{id: Livebook.Utils.random_long_id(), text: text}
+    stream_insert(socket, :chunks, chunk)
+  end
+
   @impl true
   def render(assigns) do
     ~H"""

lib/livebook_web/live/output/plain_text_component.ex

@@ -3,23 +3,36 @@ defmodule LivebookWeb.Output.PlainTextComponent do
 
   @impl true
   def mount(socket) do
-    {:ok, stream(socket, :chunks, [])}
+    {:ok,
+     socket
+     |> assign(initialized: false)
+     |> stream(:chunks, [])}
   end
 
   @impl true
+  def update(%{event: {:append, text}}, socket) do
+    {:ok, append_text(socket, text)}
+  end
+
   def update(assigns, socket) do
     {text, assigns} = Map.pop(assigns, :text)
-
     socket = assign(socket, assigns)
 
-    if text do
+    if socket.assigns.initialized do
-      chunk = %{id: Livebook.Utils.random_long_id(), text: text}
-      {:ok, stream_insert(socket, :chunks, chunk)}
-    else
       {:ok, socket}
+    else
+      {:ok,
+       socket
+       |> append_text(text)
+       |> assign(:initialized, true)}
     end
   end
 
+  defp append_text(socket, text) do
+    chunk = %{id: Livebook.Utils.random_long_id(), text: text}
+    stream_insert(socket, :chunks, chunk)
+  end
+
   @impl true
   def render(assigns) do
     ~H"""

lib/livebook_web/live/output/terminal_text_component.ex

@@ -5,16 +5,30 @@ defmodule LivebookWeb.Output.TerminalTextComponent do
   def mount(socket) do
     {:ok,
      socket
-     |> assign(modifiers: [], last_line: nil, last_html_line: nil)
+     |> assign(modifiers: [], last_line: nil, last_html_line: nil, initialized: false)
      |> stream(:html_lines, [])}
   end
 
   @impl true
+  def update(%{event: {:append, text}}, socket) do
+    {:ok, append_text(socket, text)}
+  end
+
   def update(assigns, socket) do
     {text, assigns} = Map.pop(assigns, :text)
     socket = assign(socket, assigns)
 
-    if text do
+    if socket.assigns.initialized do
+      {:ok, socket}
+    else
+      {:ok,
+       socket
+       |> append_text(text)
+       |> assign(:initialized, true)}
+    end
+  end
+
+  defp append_text(socket, text) do
     text = (socket.assigns.last_line || "") <> text
 
     text = Livebook.Notebook.normalize_terminal_text(text)
@@ -35,15 +49,11 @@ defmodule LivebookWeb.Output.TerminalTextComponent do
 
     socket = stream(socket, :html_lines, stream_items)
 
-      {:ok,
     assign(socket,
       last_html_line: last_html_line,
       last_line: last_line,
       modifiers: modifiers
-       )}
+    )
-    else
-      {:ok, socket}
-    end
   end
 
   @impl true

lib/livebook_web/live/session_live.ex

@@ -2923,14 +2923,14 @@ defmodule LivebookWeb.SessionLive do
         changed_input_ids = Session.Data.changed_input_ids(data)
 
         for {{idx, frame}, cell} <- Notebook.find_frame_outputs(data.notebook, ref) do
-          send_update(LivebookWeb.Output.FrameComponent,
-            id: "outputs-#{idx}-output",
-            outputs: frame.outputs,
-            update_type: update_type,
           # Note that we are not updating data_view to avoid re-render,
           # but any change that causes frame to re-render will update
           # data_view first
-            input_views: input_views_for_cell(cell, data, changed_input_ids)
+          input_views = input_views_for_cell(cell, data, changed_input_ids)
+
+          send_update(LivebookWeb.Output.FrameComponent,
+            id: "outputs-#{idx}-output",
+            event: {:update, update_type, frame.outputs, input_views}
           )
         end
 
@@ -2948,7 +2948,7 @@ defmodule LivebookWeb.SessionLive do
                 :markdown -> LivebookWeb.Output.MarkdownComponent
               end
 
-            send_update(module, id: "outputs-#{idx}-output", text: output.text)
+            send_update(module, id: "outputs-#{idx}-output", event: {:append, output.text})
             data_view
 
           _ ->