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lib/phoenix/code_reloader/server.ex

# The GenServer used by the CodeReloader.
defmodule Phoenix.CodeReloader.Server do
@moduledoc false
use GenServer
require Logger
alias Phoenix.CodeReloader.Proxy
def start_link(app, root, paths, opts \\ []) do
GenServer.start_link(__MODULE__, {app, root, paths}, opts)
end
def reload!(endpoint) do
children = Supervisor.which_children(endpoint)
case List.keyfind(children, __MODULE__, 0) do
{__MODULE__, pid, _, _} ->
GenServer.call(pid, :reload!, :infinity)
_ ->
raise "Code reloader was invoked for #{inspect endpoint} but no code reloader " <>
"server was started. Be sure to move `plug Phoenix.CodeReloader` inside " <>
"a `if code_reloading? do` block in your endpoint"
end
end
## Callbacks
def init({app, root, paths}) do
{:ok, {app, root, paths}}
end
def handle_call(:reload!, from, {app, root, paths} = state) do
froms = all_waiting([from])
reply = mix_compile(Code.ensure_loaded(Mix.Task), app, root, paths)
Enum.each(froms, &GenServer.reply(&1, reply))
{:noreply, state}
end
defp all_waiting(acc) do
receive do
{:"$gen_call", from, :reload!} -> all_waiting([from | acc])
after
0 -> acc
end
end
defp mix_compile({:error, _reason}, _, _, _) do
Logger.error "If you want to use the code reload plug in production or " <>
"inside an escript, add :mix to your list of dependencies or " <>
"disable code reloading"
:ok
end
defp mix_compile({:module, Mix.Task}, app, root, paths) do
if Mix.Project.umbrella? do
Mix.Project.in_project(app, root, fn _ -> mix_compile(paths) end)
else
mix_compile(paths)
end
end
defp mix_compile(paths) do
reloadable_paths = Enum.flat_map(paths, &["--elixirc-paths", &1])
Mix.Task.reenable "compile.phoenix"
Mix.Task.reenable "compile.elixir"
{res, out} =
proxy_io(fn ->
try do
Mix.Task.run "compile.phoenix"
Mix.Task.run "compile.elixir", reloadable_paths
catch
_, _ -> :error
end
end)
cond do
:error in res -> {:error, out}
:ok in res -> :ok
true -> :noop
end
end
defp proxy_io(fun) do
original_gl = Process.group_leader
{:ok, proxy_gl} = Proxy.start()
Process.group_leader(self(), proxy_gl)
try do
res = fun.()
{List.wrap(res), Proxy.stop(proxy_gl)}
after
Process.group_leader(self(), original_gl)
Process.exit(proxy_gl, :kill)
end
end
end