defmodule ElixirScript.Beam do

@moduledoc false

@doc """

Takes a module and finds the expanded AST

from the debug info inside the beam file.

For protocols, this will return a list of

all the protocol implementations

"""

@spec debug_info(atom) :: {:ok | :error, map | binary}

def debug_info(module)

#Replace some modules with ElixirScript versions

def debug_info(module) when module in [String, Agent] do

case debug_info(Module.concat(ElixirScript, module)) do

{:ok, info} ->

{:ok, Map.put(info, :module, module)}

e ->

e

end

end

def debug_info(module) when is_atom(module) do

#TODO: Get modified date from _beam_path to check for cached version?

with {_, beam, _beam_path} <- :code.get_object_code(module),

{:ok, {^module, [debug_info: {:debug_info_v1, backend, data}]}} <- :beam_lib.chunks(beam, [:debug_info]),

{:ok, {^module, attribute_info}} = :beam_lib.chunks(beam, [:attributes]) do

if Keyword.get(attribute_info[:attributes], :protocol) do

get_protocol_implementations(module)

else

backend.debug_info(:elixir_v1, module, data, [])

end

else

:error ->

{:error, "Unknown module"}

{:error,:beam_lib,{:unknown_chunk,"non_existing.beam",:debug_info}} ->

{:error, "Unsupported version of Erlang"}

{:error,:beam_lib,{:missing_chunk, _ , _}} ->

{:error, "Debug info not available"}

{:error,:beam_lib,{:file_error,"non_existing.beam",:enoent}} ->

{:error, "Debug info not available"}

end

end

defp get_protocol_implementations(module) do

implementations = module

|> Protocol.extract_impls(:code.get_path())

|> Enum.map(fn(x) -> Module.concat([module, x]) end)

|> Enum.map(fn(x) ->

case debug_info(x) do

{:ok, info} ->

{x, info}

_ ->

raise "Unable to compile protocol implementation #{inspect x}"

end

end)

{:ok, module, implementations}

end

end