alcove

#!/usr/bin/env escript

%%%
%%% Generate the alcove.erl file
%%%
main([]) ->
    ModuleName = "alcove_proto",
    Proto = "c_src/alcove_call.proto",
    main([ModuleName, Proto]);

main([ModuleName, Proto]) ->
    Module = erl_syntax:attribute(
            erl_syntax:atom(module),
            [erl_syntax:atom(ModuleName)]
            ),
    Includes = includes(["alcove.hrl"]),

    % Type specs
    Specs = erl_syntax:comment(["%__SPECS__%%"]),

    % Any hardcoded functions will be included here
    Static = erl_syntax:comment(["%__STATIC__%%"]),

    % Generate the list of exports
    Comment_static = erl_syntax:comment([" Static functions"]),
    Exports_static = erl_syntax:attribute(erl_syntax:atom(export), [
                erl_syntax:list([
                    erl_syntax:arity_qualifier(erl_syntax:atom(Fun), erl_syntax:integer(Arity))
                        || {Fun, Arity} <- static_exports() ])
                ]),

    Comment_gen = erl_syntax:comment([" Generated functions"]),
    Exports_gen = erl_syntax:attribute(erl_syntax:atom(export), [
                erl_syntax:list([
                    erl_syntax:arity_qualifier(erl_syntax:atom(calls), erl_syntax:integer(0))
                ])]),

    Body = erl_syntax:list([ erl_syntax:atom(N) || {N,_} <- proto(Proto) ]),
    Clause = erl_syntax:clause([], [], [Body]),
    Fun = [erl_syntax:function(erl_syntax:atom("calls"), [Clause])],

    Code0 = erl_prettypr:format(erl_syntax:form_list(lists:flatten([
                license(),
                Module,
                Includes,

                Specs,

                Comment_static,
                Exports_static,

                Comment_gen,
                Exports_gen,

                Static,
                Fun
            ]))),

    Code = lists:foldl(fun({Marker, Generated}, Text) ->
                re:replace(Text, Marker, Generated)
        end,
        Code0,
        [
            {"%%__STATIC__%%", static()},
            {"%%__SPECS__%%", specs()}
        ]),

    io:format("~s~n", [Code]).

% List the supported alcove API functions
proto(Proto) ->
    {ok, Bin} = file:read_file(Proto),
    Fun = binary:split(Bin, <<"\n">>, [trim,global]),
    call_to_fun(Fun, []).

call_to_fun([], Acc) ->
    lists:reverse(Acc);
call_to_fun([H|T], Acc) ->
    [Fun, Arity] = binary:split(H, <<"/">>),
    call_to_fun(T, [{binary_to_list(Fun), b2i(Arity)}|Acc]).

b2i(N) when is_binary(N) ->
    list_to_integer(binary_to_list(N)).

static_exports() ->
    [{call,1},{will_return,1}].

static() ->
    [ static({Fun, Arity}) || {Fun, Arity} <- static_exports() ].

static({call,1}) ->
"
call(Call) when is_atom(Call) ->
    lookup(Call, calls(), 0).

lookup(Call, [Call|_], N) ->
    N;
lookup(Call, [_|Calls], N) ->
    lookup(Call, Calls, N+1).
";

static({will_return,1}) ->
"
will_return(execve) -> false;
will_return(execvp) -> false;
will_return(exit) -> false;
will_return(fexecve) -> false;
will_return(_) -> true.
".

includes(Header) ->
    [ erl_syntax:attribute(erl_syntax:atom(include), [erl_syntax:string(N)]) || N <- Header ].

% FIXME hack for hard coding typespecs
specs() ->
"".

license() ->
    {{Year,_,_},{_,_,_}} = calendar:universal_time(),

    Date = integer_to_list(Year),

    License = [
" Copyright (c) " ++ Date ++ ", Michael Santos <michael.santos@gmail.com>",
" Permission to use, copy, modify, and/or distribute this software for any",
" purpose with or without fee is hereby granted, provided that the above",
" copyright notice and this permission notice appear in all copies.",
"",
" THE SOFTWARE IS PROVIDED \"AS IS\" AND THE AUTHOR DISCLAIMS ALL WARRANTIES",
" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF",
" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR",
" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES",
" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN",
" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF",
" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE."],

    erl_syntax:comment(License).