Cache icon bodies and components

lib/heroicons/icon_cache.ex

@@ -1,8 +1,64 @@
 defmodule Heroicons.IconCache do
-
   @doc "Get's an icon's body from the filesystem"
-  # TODO implement ETS-based caching & benchmark
-  def icon_body(path) do
+  use GenServer
+
+  @name __MODULE__
+
+  def start_link(_), do: GenServer.start_link(__MODULE__, [], name: @name)
+
+  def fetch_component(path) do
+    case :ets.lookup(@name.Components, path) do
+      [{^path, component}] ->
+        component
+
+      [] ->
+        GenServer.call(@name, {:cache_component, path})
+    end
+  end
+
+  def fetch_body(path) do
+    case :ets.lookup(@name, path) do
+      [{^path, body}] ->
+        body
+
+      [] ->
+        GenServer.call(@name, {:cache_body, path})
+    end
+  end
+
+  def init(_) do
+    :ets.new(@name, [:set, :protected, :named_table])
+    :ets.new(@name.Components, [:set, :protected, :named_table])
+
+    {:ok, []}
+  end
+
+  def handle_call({:cache_body, path}, _ref, state) do
+    body = read_body(path)
+
+    :ets.insert_new(@name, {path, body})
+
+    {:reply, body, 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
     icon = File.read!(path)
 
     <<"<svg ", body::binary>> = icon