From 0726bf67819cab62336819faabfe6756d75a03a3 Mon Sep 17 00:00:00 2001
From: Max Veytsman <maxim@ontoillogical.com>
Date: Fri, 2 Sep 2022 21:01:48 -0400
Subject: [PATCH] Optimize Phoenix Component caching

---
 lib/heroicons/cache.ex     | 55 ++++++++++----------------------------
 lib/heroicons/generator.ex | 37 +++++++++++++++++++------
 2 files changed, 43 insertions(+), 49 deletions(-)

diff --git a/lib/heroicons/cache.ex b/lib/heroicons/cache.ex
index c7b85a0..7e83689 100644
--- a/lib/heroicons/cache.ex
+++ b/lib/heroicons/cache.ex
@@ -12,69 +12,42 @@ defmodule Heroicons.Cache do
   @doc false
   def start_link(_), do: GenServer.start_link(__MODULE__, [], name: @name)
 
-  @doc "Fetch a pre-compiled Phoenix Component from the cache or disk, given a `path`"
-  def fetch_component(path) do
-    case :ets.lookup(@name.Components, path) do
-      [{^path, component}] ->
-        component
-
-      [] ->
-        GenServer.call(@name, {:cache_component, path})
-    end
-  end
-
-  @doc "Fetch a icon's body from the cache or disk, given a `path`"
-  def fetch_body(path) do
+  @doc "Fetch a icon's body and fingerprint from the cache or disk, given a `path`"
+  def fetch_icon(path) do
     case :ets.lookup(@name, path) do
-      [{^path, body}] ->
-        body
+      [{^path, icon_body, fingerprint}] ->
+        {icon_body, fingerprint}
 
       [] ->
-        GenServer.call(@name, {:cache_body, path})
+        GenServer.call(@name, {:cache_icon, path})
     end
   end
 
   @impl true
   def init(_) do
     :ets.new(@name, [:set, :protected, :named_table])
-    :ets.new(@name.Components, [:set, :protected, :named_table])
 
     {:ok, []}
   end
 
   @impl true
-  def handle_call({:cache_body, path}, _ref, state) do
-    body = read_body(path)
+  def handle_call({:cache_icon, path}, _ref, state) do
+    {icon_body, fingerprint} = read_icon(path)
 
-    :ets.insert_new(@name, {path, body})
+    :ets.insert_new(@name, {path, icon_body, fingerprint})
 
-    {:reply, body, state}
+    {:reply, {icon_body, fingerprint}, state}
   end
 
-  def handle_call({:cache_component, path}, _ref, state) do
-    body = read_body(path)
-
-    component =
-      EEx.compile_string("<svg {@attrs}" <> body,
-        engine: Phoenix.LiveView.HTMLEngine,
-        file: __ENV__.file,
-        line: __ENV__.line + 1,
-        module: __ENV__.module,
-        indentation: 0
-      )
-
-    :ets.insert_new(@name.Components, {path, component})
-
-    {:reply, component, state}
-  end
-
-  defp read_body(path) do
+  defp read_icon(path) do
     icon =
       Path.join(:code.priv_dir(:heroicons), path)
       |> File.read!()
 
-    <<"<svg ", body::binary>> = icon
+    <<"<svg", icon_body::binary>> = icon
 
-    body
+    <<fingerprint::8*16>> = :erlang.md5(icon)
+
+    {icon_body, fingerprint}
   end
 end
diff --git a/lib/heroicons/generator.ex b/lib/heroicons/generator.ex
index b921fd5..34bd170 100644
--- a/lib/heroicons/generator.ex
+++ b/lib/heroicons/generator.ex
@@ -71,13 +71,33 @@ defmodule Heroicons.Generator do
     attrs = @assigns_to_attrs_mod.assigns_to_attributes(assigns)
     assigns = @assign_mod.assign(assigns, :attrs, attrs)
 
-    {component, _binding} =
-      Code.eval_quoted(
-        Heroicons.Cache.fetch_component(path),
-        assigns: assigns
-      )
+    dynamic = fn track_changes? ->
+      changed =
+        case assigns do
+          %{__changed__: changed} when track_changes? -> changed
+          _ -> nil
+        end
 
-    component
+      attrs =
+        case Phoenix.LiveView.Engine.changed_assign?(changed, :attrs) do
+          true -> elem(Phoenix.HTML.attributes_escape(assigns.attrs), 1)
+          false -> nil
+        end
+
+      [attrs]
+    end
+
+    {icon_body, fingerprint} = Heroicons.Cache.fetch_icon(path)
+
+    %Phoenix.LiveView.Rendered{
+      static: [
+        "<svg",
+        icon_body
+      ],
+      dynamic: dynamic,
+      fingerprint: fingerprint,
+      root: true
+    }
   end
 
   @doc false
@@ -92,12 +112,13 @@ defmodule Heroicons.Generator do
         {:safe, [?\s, safe_k, ?=, ?", safe_v, ?"]}
       end
 
+    {icon_body, _fingerprint} = Heroicons.Cache.fetch_icon(path)
+
     {:safe,
      [
        "<svg",
        Phoenix.HTML.Safe.to_iodata(attrs),
-       " ",
-       Heroicons.Cache.fetch_body(path)
+       icon_body
      ]}
   end
 end