bootstrap

#!/usr/bin/env escript
%% -*- mode: erlang;erlang-indent-level: 4;indent-tabs-mode: nil -*-
%% ex: ft=erlang ts=4 sw=4 et

main(_Args) ->
    %% Fetch and build deps required to build rebar3
    BaseDeps = [{providers, []}
               ,{getopt, []}
               ,{erlware_commons, ["ec_dictionary.erl", "ec_vsn.erl"]}],
    Deps = get_deps(),
    [fetch_and_compile(Dep, Deps) || Dep <- BaseDeps],

    %% Build rebar3 modules with compile:file
    bootstrap_rebar3(),

    %% Build rebar.app from rebar.app.src
    {ok, App} = rebar_app_info:new(rebar, "3.0.0", filename:absname("_build/default/lib/rebar/")),
    rebar_otp_app:compile(rebar_state:new(), App),

    %% Because we are compiling files that are loaded already we want to silence
    %% not_purged errors in rebar_erlc_compiler:opts_changed/1
    error_logger:tty(false),

    setup_env(),
    os:putenv("REBAR_PROFILE", "bootstrap"),
    {ok, State} = rebar3:run(["compile"]),
    reset_env(),
    os:putenv("REBAR_PROFILE", ""),

    DepsPaths = rebar_state:code_paths(State, all_deps),
    code:add_pathsa(DepsPaths),

    rebar3:run(["clean", "-a"]),
    rebar3:run(["escriptize"]),

    %% Done with compile, can turn back on error logger
    error_logger:tty(true),

    %% Finally, update executable perms for our script on *nix,
    %%  or write out script files on win32.
    ec_file:copy("_build/default/bin/rebar3", "./rebar3"),
    case os:type() of
        {unix,_} ->
            [] = os:cmd("chmod u+x rebar3"),
            ok;
        {win32,_} ->
            write_windows_scripts(),
            ok;
        _ ->
            ok
    end.

fetch_and_compile({Name, ErlFirstFiles}, Deps) ->
    {Name, _, Repo} = lists:keyfind(Name, 1, Deps),
    ok = fetch(Repo, Name),
    compile(Name, ErlFirstFiles).

fetch({git, Url, Source}, App) ->
    Dir = filename:join([filename:absname("_build/default/lib/"), App]),
    case filelib:is_dir(Dir) of
        true ->
            true = code:add_path(filename:join(Dir, "ebin")),
            ok;
        false ->
            fetch_source(Dir, Url, Source),
            ok
    end.

fetch_source(Dir, Url, {ref, Ref}) ->
    ok = filelib:ensure_dir(Dir),
    os:cmd(io_lib:format("git clone ~s ~s", [Url, Dir])),
    {ok, Cwd} = file:get_cwd(),
    file:set_cwd(Dir),
    os:cmd(io_lib:format("git checkout -q ~s", [Ref])),
    file:set_cwd(Cwd);
fetch_source(Dir, Url, {_, Branch}) ->
    ok = filelib:ensure_dir(Dir),
    os:cmd(io_lib:format("git clone ~s ~s -b ~s --single-branch",
                         [Url, Dir, Branch])).

compile(App, FirstFiles) ->
    Dir = filename:join(filename:absname("_build/default/lib/"), App),
    filelib:ensure_dir(filename:join([Dir, "ebin", "dummy.beam"])),
    code:add_path(filename:join(Dir, "ebin")),
    FirstFilesPaths = [filename:join([Dir, "src", Module]) || Module <- FirstFiles],
    Sources = FirstFilesPaths ++ filelib:wildcard(filename:join([Dir, "src", "*.erl"])),
    [compile_file(X, [{i, filename:join(Dir, "include")}
                     ,{outdir,  filename:join(Dir, "ebin")}
                     ,return | additional_defines()]) || X <- Sources].

compile_file(File, Opts) ->
    case compile:file(File, Opts) of
        {ok, _Mod} ->
            ok;
        {ok, _Mod, []} ->
            ok;
        {ok, _Mod, Ws} ->
            io:format("~s~n", [format_warnings(File, Ws)]),
            halt(1);
        {error, Es, Ws} ->
            io:format("~s ~s~n", [format_errors(File, Es), format_warnings(File, Ws)]),
            halt(1)
    end.

bootstrap_rebar3() ->
    filelib:ensure_dir("_build/default/lib/rebar/ebin/dummy.beam"),
    code:add_path("_build/default/lib/rebar/ebin/"),
    file:make_symlink(filename:absname("src"), filename:absname("_build/default/lib/rebar/src")),
    Sources = ["src/rebar_resource.erl" | filelib:wildcard("src/*.erl")],
    [compile_file(X, [{outdir, "_build/default/lib/rebar/ebin/"}
                     ,return | additional_defines()]) || X <- Sources],
    code:add_patha(filename:absname("_build/default/lib/rebar/ebin")).

setup_env() ->
    %% We don't need or want relx providers loaded yet
    application:load(rebar),
    {ok, Providers} = application:get_env(rebar, providers),
    Providers1 = Providers -- [rebar_prv_release,
                               rebar_prv_tar],
    application:set_env(rebar, providers, Providers1).

reset_env() ->
    %% Reset the env so we get all providers
    application:unset_env(rebar, providers),
    application:unload(rebar),
    application:load(rebar).

write_windows_scripts() ->
    CmdScript=
        "@echo off\r\n"
        "setlocal\r\n"
        "set rebarscript=%~f0\r\n"
        "escript.exe \"%rebarscript:.cmd=%\" %*\r\n",
    ok = file:write_file("rebar3.cmd", CmdScript).

get_deps() ->
    case file:consult("rebar.lock") of
        {ok, [Deps]} ->
            [{binary_to_atom(Name, utf8), "", Source} || {Name, Source, _Level} <- Deps];
        _ ->
            {ok, Config} = file:consult("rebar.config"),
            proplists:get_value(deps, Config)
    end.

format_errors(Source, Errors) ->
    format_errors(Source, "", Errors).

format_warnings(Source, Warnings) ->
    format_warnings(Source, Warnings, []).

format_warnings(Source, Warnings, Opts) ->
    Prefix = case lists:member(warnings_as_errors, Opts) of
                 true -> "";
                 false -> "Warning: "
             end,
    format_errors(Source, Prefix, Warnings).

format_errors(_MainSource, Extra, Errors) ->
    [begin
         [format_error(Source, Extra, Desc) || Desc <- Descs]
     end
     || {Source, Descs} <- Errors].

format_error(AbsSource, Extra, {{Line, Column}, Mod, Desc}) ->
    ErrorDesc = Mod:format_error(Desc),
    io_lib:format("~s:~w:~w: ~s~s~n", [AbsSource, Line, Column, Extra, ErrorDesc]);
format_error(AbsSource, Extra, {Line, Mod, Desc}) ->
    ErrorDesc = Mod:format_error(Desc),
    io_lib:format("~s:~w: ~s~s~n", [AbsSource, Line, Extra, ErrorDesc]);
format_error(AbsSource, Extra, {Mod, Desc}) ->
    ErrorDesc = Mod:format_error(Desc),
    io_lib:format("~s: ~s~s~n", [AbsSource, Extra, ErrorDesc]).

additional_defines() ->
    [{d, D} || {Re, D} <- [{"^[0-9]+", namespaced_types}, {"^R1[4|5]", deprecated_crypto}], is_otp_release(Re)].

is_otp_release(ArchRegex) ->
    case re:run(otp_release(), ArchRegex, [{capture, none}]) of
        match ->
            true;
        nomatch ->
            false
    end.

otp_release() ->
    otp_release1(erlang:system_info(otp_release)).

%% If OTP <= R16, otp_release is already what we want.
otp_release1([$R,N|_]=Rel) when is_integer(N) ->
    Rel;
%% If OTP >= 17.x, erlang:system_info(otp_release) returns just the
%% major version number, we have to read the full version from
%% a file. See http://www.erlang.org/doc/system_principles/versions.html
%% Read vsn string from the 'OTP_VERSION' file and return as list without
%% the "\n".
otp_release1(Rel) ->
    File = filename:join([code:root_dir(), "releases", Rel, "OTP_VERSION"]),
    {ok, Vsn} = file:read_file(File),

    %% It's fine to rely on the binary module here because we can
    %% be sure that it's available when the otp_release string does
    %% not begin with $R.
    Size = byte_size(Vsn),
    %% The shortest vsn string consists of at least two digits
    %% followed by "\n". Therefore, it's safe to assume Size >= 3.
    case binary:part(Vsn, {Size, -3}) of
        <<"**\n">> ->
            %% The OTP documentation mentions that a system patched
            %% using the otp_patch_apply tool available to licensed
            %% customers will leave a '**' suffix in the version as a
            %% flag saying the system consists of application versions
            %% from multiple OTP versions. We ignore this flag and
            %% drop the suffix, given for all intents and purposes, we
            %% cannot obtain relevant information from it as far as
            %% tooling is concerned.
            binary:bin_to_list(Vsn, {0, Size - 3});
        _ ->
            binary:bin_to_list(Vsn, {0, Size - 1})
    end.