Defines the Nerves package platform behaviour

This behaviour is implemented on a module that would be used to construct an artifact for a nerves package. Nerves packages are prioritized to be compiled before any other dependencies, therefore, a package platform is useful for constructing host tools to be used during the elixir compile phase.

You can implement both Nerves.Package.Platform and Nerves.Artifact.BuildRunner in the same module with the using macro.

Here is a simple example that touches a file in the Artifact.build_path

defmodule SystemPlatform do
  use Nerves.Package.Platform

  def bootstrap(_pkg) do
    System.put_env("NERVES_BOOTSTRAP_SYSTEM", "1")
    :ok
  end

  def build(pkg, _toolchain, _opts) do
    build_path = Artifact.build_path(pkg)
    File.rm_rf!(build_path)
    File.mkdir_p!(build_path)

    build_path
    |> Path.join("file")
    |> File.touch()

    {:ok, build_path}
  end

  def build_path_link(pkg) do
    Artifact.build_path(pkg)
  end

  def archive(pkg, _toolchain, _opts) do
    build_path = Artifact.build_path(pkg)
    name = Artifact.download_name(pkg) <> Artifact.ext(pkg)
    Nerves.Utils.File.tar(build_path, name)
    {:ok, Path.join(File.cwd!, name)}
  end

  def clean(pkg) do
    Artifact.build_path(pkg)
    |> File.rm_rf()
  end
end