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lib/credo/code/module.ex

defmodule Credo.Code.Module do
@moduledoc """
This module provides helper functions to analyse modules, return the defined
funcions or module attributes.
"""
alias Credo.Code
alias Credo.Code.Block
@def_ops [:def, :defp, :defmacro]
@doc "Reads an attribute from a module's `ast`"
def attribute(ast, attr_name) do
case Credo.Code.postwalk(ast, &find_attribute(&1, &2, attr_name), {:error, nil}) do
{:ok, value} -> value
error -> error
end
end
@doc "Returns the function/macro count for the given module's AST"
def def_count(nil), do: 0
def def_count({:defmodule, _, _arguments} = ast) do
ast
|> Code.postwalk(&traverse_mod/2)
|> Enum.count
end
@doc "Returns the arity of the given function definition `ast`"
for op <- @def_ops do
def def_arity({unquote(op) = op, _, [{:when, _, fun_ast}, _]}) do
def_arity({op, nil, fun_ast})
end
def def_arity({unquote(op), _, [{_fun_name, _, arguments}, _]}) when is_list(arguments) do
Enum.count(arguments)
end
def def_arity({unquote(op), _, [{_fun_name, _, _}, _]}), do: 0
end
def def_arity(_), do: nil
@doc "Returns the name of the function/macro defined in the given `ast`"
for op <- @def_ops do
def def_name({unquote(op) = op, _, [{:when, _, fun_ast}, _]}) do
def_name({op, nil, fun_ast})
end
def def_name({unquote(op), _, [{fun_name, _, _arguments}, _]}) when is_atom(fun_name) do
fun_name
end
end
def def_name(_), do: nil
@doc "Returns the {fun_name, op} tuple of the function/macro defined in the given `ast`"
for op <- @def_ops do
def def_name_with_op({unquote(op) = op, _, _} = ast) do
{ast |> def_name, op}
end
def def_name_with_op({unquote(op) = op, _, _} = ast, arity) do
if ast |> def_arity() == arity do
{ast |> def_name, op}
else
nil
end
end
end
def def_name_with_op(_), do: nil
@doc "Returns the name of the functions/macros for the given module's `ast`"
def def_names(nil), do: []
def def_names({:defmodule, _, _arguments} = ast) do
ast
|> Code.postwalk(&traverse_mod/2)
|> Enum.map(&def_name/1)
|> Enum.uniq
end
@doc "Returns the name of the functions/macros for the given module's `ast`"
def def_names_with_op(nil), do: []
def def_names_with_op({:defmodule, _, _arguments} = ast) do
ast
|> Code.postwalk(&traverse_mod/2)
|> Enum.map(&def_name_with_op/1)
|> Enum.uniq
end
@doc "Returns the name of the functions/macros for the given module's `ast` if it has the given `arity`."
def def_names_with_op(nil, _arity), do: []
def def_names_with_op({:defmodule, _, _arguments} = ast, arity) do
ast
|> Code.postwalk(&traverse_mod/2)
|> Enum.map(&def_name_with_op(&1, arity))
|> Enum.reject(&is_nil/1)
|> Enum.uniq
end
@doc "Returns the list of modules used in a given module source code (dependent modules)"
def modules({:defmodule, _, _arguments} = ast) do
ast
|> Code.postwalk(&find_dependent_modules/2)
|> Enum.uniq
end
@doc "Returns the list of aliases defined in a given module source code"
def aliases({:defmodule, _, _arguments} = ast) do
ast
|> Credo.Code.postwalk(&find_aliases/2)
|> Enum.uniq
end
#
# PRIVATE STUFF
#
# Single alias
defp find_aliases({:alias, _, [{:__aliases__, _, mod_list}]} = ast, aliases) do
module_names = mod_list |> Credo.Code.Name.full |> List.wrap
{ast, aliases ++ module_names}
end
# Multi alias
defp find_aliases({:alias, _, [{{:., _, [{:__aliases__, _, mod_list}, :{}]}, _, multi_mod_list}]} = ast, aliases) do
module_names =
multi_mod_list
|> Enum.map(fn(tuple) ->
[Credo.Code.Name.full(mod_list), Credo.Code.Name.full(tuple)] |> Credo.Code.Name.full
end)
{ast, aliases ++ module_names}
end
defp find_aliases(ast, aliases) do
{ast, aliases}
end
defp find_attribute({:@, _meta, arguments} = ast, tuple, attribute_name) do
case arguments |> List.first do
{^attribute_name, _meta, [value]} -> {:ok, value}
_ -> {ast, tuple}
end
end
defp find_attribute(ast, tuple, _name) do
{ast, tuple}
end
# exclude module name
defp find_dependent_modules({:defmodule, _, [{:__aliases__, _, mod_list}, _do_block]} = ast, modules) do
module_names = mod_list |> Credo.Code.Name.full |> List.wrap
{ast, modules -- module_names}
end
# single alias
defp find_dependent_modules({:alias, _, [{:__aliases__, _, mod_list}]} = ast, aliases) do
module_names = mod_list |> Credo.Code.Name.full |> List.wrap
{ast, aliases -- module_names}
end
# multi alias
defp find_dependent_modules({:alias, _, [{{:., _, [{:__aliases__, _, mod_list}, :{}]}, _, multi_mod_list}]} = ast, modules) do
module_names =
multi_mod_list
|> Enum.flat_map(fn(tuple) ->
[Credo.Code.Name.full(mod_list), Credo.Code.Name.full(tuple)]
end)
{ast, modules -- module_names}
end
defp find_dependent_modules({:__aliases__, _, mod_list} = ast, modules) do
module_names = mod_list |> Credo.Code.Name.full |> List.wrap
{ast, modules ++ module_names}
end
defp find_dependent_modules(ast, modules) do
{ast, modules}
end
for op <- @def_ops do
defp traverse_mod({:@, _, [{unquote(op), _, arguments} = ast]}, defs) when is_list(arguments) do
{ast, defs -- [ast]}
end
defp traverse_mod({unquote(op), _, arguments} = ast, defs) when is_list(arguments) do
{ast, defs ++ [ast]}
end
end
defp traverse_mod(ast, defs) do
{ast, defs}
end
# TODO: write unit test
def name({:defmodule, _, [{:__aliases__, _, name_list}, _]}) do
Enum.join(name_list, ".")
end
def name(_), do: nil
# TODO: write unit test
def exception?({:defmodule, _, [{:__aliases__, _, _name_list}, arguments]}) do
arguments
|> Block.calls_in_do_block
|> Enum.any?(&defexception?/1)
end
def exception?(_), do: nil
defp defexception?({:defexception, _, _}), do: true
defp defexception?(_), do: false
end