feat: pipeline to create a full mac app

lib/bds/mac_bundle/dylibs.ex

@@ -0,0 +1,158 @@
+defmodule BDS.MacBundle.Dylibs do
+  @moduledoc """
+  Makes the bundled Elixir release self-contained on macOS by relocating the
+  non-system dynamic libraries the wxWidgets NIF (`wxe_driver.so`) links against.
+
+  Erlang's `:wx` driver is built against the wxWidgets dylibs of whatever host
+  produced the OTP install (typically Homebrew under `/opt/homebrew`), so a
+  release copied to a clean Mac would fail to load `:wx`. We copy every external
+  dylib (and its transitive deps) into `Contents/Frameworks/`, then rewrite the
+  install names with `install_name_tool` to `@executable_path/../Frameworks/...`.
+
+  The `otool`/`install_name_tool` parsing and argument building are pure so they
+  can be unit-tested; `bundle/2` performs the actual filesystem + tool work.
+  """
+
+  # Homebrew prefixes whose libraries must be copied into the bundle. Anything
+  # under /usr/lib or /System is part of macOS and stays referenced in place;
+  # @rpath/@executable_path/@loader_path are already relocatable.
+  @external_prefixes ["/opt/homebrew", "/usr/local"]
+
+  @doc "Parse `otool -L` output into the ordered list of dependency paths."
+  @spec parse_otool(String.t()) :: [String.t()]
+  def parse_otool(output) when is_binary(output) do
+    output
+    |> String.split("\n", trim: true)
+    # The first line is the inspected file ("path:"), not a dependency.
+    |> Enum.filter(&String.starts_with?(&1, "\t"))
+    |> Enum.map(fn line ->
+      line
+      |> String.trim()
+      |> String.replace(~r/\s+\(compatibility version.*\)$/, "")
+      |> String.trim()
+    end)
+  end
+
+  @doc "True when a dylib path must be copied into the bundle (Homebrew/local)."
+  @spec external?(String.t()) :: boolean()
+  def external?(path) when is_binary(path) do
+    Enum.any?(@external_prefixes, &String.starts_with?(path, &1))
+  end
+
+  @doc "install_name_tool args to set a dylib's own id."
+  @spec id_args(String.t(), String.t()) :: [String.t()]
+  def id_args(dylib_path, new_id), do: ["-id", new_id, dylib_path]
+
+  @doc """
+  install_name_tool args to rewrite zero or more dependency install names on a
+  binary. Returns `[]` when there are no changes so callers can skip the tool.
+  """
+  @spec change_args(String.t(), [{String.t(), String.t()}]) :: [String.t()]
+  def change_args(_binary, []), do: []
+
+  def change_args(binary, changes) when is_list(changes) do
+    Enum.flat_map(changes, fn {old, new} -> ["-change", old, new] end) ++ [binary]
+  end
+
+  @doc """
+  Copy every external dylib reachable from `nif_path` into `frameworks_dir` and
+  rewrite all install names (in the NIF and the copied dylibs) to point inside
+  the bundle. Returns `{:ok, copied_paths}`.
+
+  References are made `@loader_path`-relative so they resolve against the binary
+  that triggers the load — independent of where the host process executable
+  lives (the release runs `beam.smp`, not the bundle launcher) and without any
+  `DYLD_*` env reliance:
+
+    * the NIF references each dylib as `<nif_loader_prefix>/<basename>`, where
+      `nif_loader_prefix` is the `@loader_path/../…/Frameworks` path from the
+      NIF's directory to `frameworks_dir`;
+    * the copied dylibs live together, so they reference each other (and their
+      own id) as `@loader_path/<basename>`.
+  """
+  @spec bundle(String.t(), String.t(), String.t()) ::
+          {:ok, [String.t()]} | {:error, term()}
+  def bundle(nif_path, frameworks_dir, nif_loader_prefix) do
+    File.mkdir_p!(frameworks_dir)
+
+    with {:ok, {_seen, externals}} <- collect(nif_path, MapSet.new(), []) do
+      copied =
+        externals
+        |> Enum.reverse()
+        |> Enum.map(fn src ->
+          dest = Path.join(frameworks_dir, Path.basename(src))
+          File.cp!(src, dest)
+          File.chmod!(dest, 0o644)
+          {src, dest}
+        end)
+
+      with :ok <- rewrite(nif_path, copied, nif_loader_prefix),
+           :ok <- rewrite_each(copied) do
+        {:ok, Enum.map(copied, &elem(&1, 1))}
+      end
+    end
+  end
+
+  # Depth-first transitive collection of external dependency paths. Returns
+  # `{:ok, {seen, acc}}` where `acc` is the reverse-discovery-order path list.
+  defp collect(binary, seen, acc) do
+    case otool(binary) do
+      {:ok, deps} ->
+        deps
+        |> Enum.filter(&external?/1)
+        |> Enum.reject(&MapSet.member?(seen, &1))
+        |> Enum.reduce_while({:ok, {seen, acc}}, fn dep, {:ok, {seen_acc, list_acc}} ->
+          seen_acc = MapSet.put(seen_acc, dep)
+
+          case collect(dep, seen_acc, [dep | list_acc]) do
+            {:ok, _} = ok -> {:cont, ok}
+            error -> {:halt, error}
+          end
+        end)
+
+      error ->
+        error
+    end
+  end
+
+  defp rewrite(binary, copied, prefix) do
+    changes =
+      Enum.map(copied, fn {src, dest} ->
+        {src, prefix <> "/" <> Path.basename(dest)}
+      end)
+
+    case change_args(binary, changes) do
+      [] -> :ok
+      args -> run("install_name_tool", args)
+    end
+  end
+
+  # Copied dylibs share Frameworks/, so they reference each other (and their own
+  # id) relative to their own location with @loader_path.
+  defp rewrite_each(copied) do
+    Enum.reduce_while(copied, :ok, fn {_src, dest}, _acc ->
+      base = Path.basename(dest)
+
+      with :ok <- run("install_name_tool", id_args(dest, "@loader_path/" <> base)),
+           :ok <- rewrite(dest, copied, "@loader_path") do
+        {:cont, :ok}
+      else
+        error -> {:halt, error}
+      end
+    end)
+  end
+
+  defp otool(path) do
+    case System.cmd("otool", ["-L", path], stderr_to_stdout: true) do
+      {out, 0} -> {:ok, parse_otool(out)}
+      {out, status} -> {:error, {:otool_failed, status, out}}
+    end
+  end
+
+  defp run(cmd, args) do
+    case System.cmd(cmd, args, stderr_to_stdout: true) do
+      {_out, 0} -> :ok
+      {out, status} -> {:error, {:command_failed, cmd, status, out}}
+    end
+  end
+end