summaryrefslogtreecommitdiff
path: root/src/rebar_erlc_compiler.erl
blob: 9bebefb2da991d469bdc3c35b0e36bf605886bf7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
%% ex: ts=4 sw=4 et
%% -------------------------------------------------------------------
%%
%% rebar: Erlang Build Tools
%%
%% Copyright (c) 2009, 2010 Dave Smith (dizzyd@dizzyd.com)
%%
%% Permission is hereby granted, free of charge, to any person obtaining a copy
%% of this software and associated documentation files (the "Software"), to deal
%% in the Software without restriction, including without limitation the rights
%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
%% copies of the Software, and to permit persons to whom the Software is
%% furnished to do so, subject to the following conditions:
%%
%% The above copyright notice and this permission notice shall be included in
%% all copies or substantial portions of the Software.
%%
%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
%% THE SOFTWARE.
%% -------------------------------------------------------------------
-module(rebar_erlc_compiler).

-export([compile/2,
         clean/2]).

%% for internal use only
-export([test_compile/3,
         info/2]).

-include("rebar.hrl").
-include_lib("stdlib/include/erl_compile.hrl").

-define(ERLCINFO_VSN, 1).
-define(ERLCINFO_FILE, "erlcinfo").
-type erlc_info_v() :: {digraph:vertex(), term()} | 'false'.
-type erlc_info_e() :: {digraph:vertex(), digraph:vertex()}.
-type erlc_info() :: {list(erlc_info_v()), list(erlc_info_e())}.
-record(erlcinfo,
        {
          vsn = ?ERLCINFO_VSN :: pos_integer(),
          info = {[], []} :: erlc_info()
        }).

-define(RE_PREFIX, "^[^._]").

-ifdef(namespaced_types).
%% digraph:graph() exists starting from Erlang 17.
-type rebar_digraph() :: digraph:graph().
-else.
%% digraph() has been obsoleted in Erlang 17 and deprecated in 18.
-type rebar_digraph() :: digraph().
-endif.

%% ===================================================================
%% Public API
%% ===================================================================

%% Supported configuration variables:
%%
%% * erl_opts - Erlang list of options passed to compile:file/2
%%              It is also possible to specify platform specific
%%              options by specifying a pair or a triplet where the
%%              first string is a regex that is checked against the
%%              string
%%
%%                OtpRelease ++ "-" ++ SysArch ++ "-" ++ Words.
%%
%%              where
%%
%%                OtpRelease = erlang:system_info(otp_release).
%%                SysArch = erlang:system_info(system_architecture).
%%                Words = integer_to_list(8 *
%%                            erlang:system_info({wordsize, external})).
%%
%%              E.g. to define HAVE_SENDFILE only on systems with
%%              sendfile(), to define BACKLOG on Linux/FreeBSD as 128,
%%              and to define 'old_inets' for R13 OTP release do:
%%
%%              {erl_opts, [{platform_define,
%%                           "(linux|solaris|freebsd|darwin)",
%%                           'HAVE_SENDFILE'},
%%                          {platform_define, "(linux|freebsd)",
%%                           'BACKLOG', 128},
%%                          {platform_define, "R13",
%%                           'old_inets'}]}.
%%

-spec compile(rebar_state:t(), file:name()) -> 'ok'.
compile(Config, Dir) ->
    rebar_base_compiler:run(Config,
                            check_files(rebar_state:get(
                                          Config, xrl_first_files, [])),
                            "src", ".xrl", "src", ".erl",
                            fun compile_xrl/3),
    rebar_base_compiler:run(Config,
                            check_files(rebar_state:get(
                                          Config, yrl_first_files, [])),
                            "src", ".yrl", "src", ".erl",
                            fun compile_yrl/3),
    rebar_base_compiler:run(Config,
                            check_files(rebar_state:get(
                                          Config, mib_first_files, [])),
                            "mibs", ".mib", "priv/mibs", ".bin",
                            fun compile_mib/3),
    doterl_compile(Config, Dir).

-spec clean(rebar_state:t(), file:filename()) -> 'ok'.
clean(Config, _AppFile) ->
    MibFiles = rebar_utils:find_files("mibs", ?RE_PREFIX".*\\.mib\$"),
    MIBs = [filename:rootname(filename:basename(MIB)) || MIB <- MibFiles],
    rebar_file_utils:delete_each(
      [filename:join(["include",MIB++".hrl"]) || MIB <- MIBs]),
    lists:foreach(fun(F) -> ok = rebar_file_utils:rm_rf(F) end,
                  ["ebin/*.beam", "priv/mibs/*.bin"]),

    YrlFiles = rebar_utils:find_files("src", ?RE_PREFIX".*\\.[x|y]rl\$"),
    rebar_file_utils:delete_each(
      [ binary_to_list(iolist_to_binary(re:replace(F, "\\.[x|y]rl$", ".erl")))
        || F <- YrlFiles ]),

    %% Delete the build graph, if any
    rebar_file_utils:rm_rf(erlcinfo_file(Config)),

    %% Erlang compilation is recursive, so it's possible that we have a nested
    %% directory structure in ebin with .beam files within. As such, we want
    %% to scan whatever is left in the ebin/ directory for sub-dirs which
    %% satisfy our criteria.
    BeamFiles = rebar_utils:find_files("ebin", ?RE_PREFIX".*\\.beam\$"),
    rebar_file_utils:delete_each(BeamFiles),
    lists:foreach(fun(Dir) -> delete_dir(Dir, dirs(Dir)) end, dirs("ebin")),
    ok.

%% ===================================================================
%% .erl Compilation API (externally used by only eunit and qc)
%% ===================================================================

test_compile(Config, Cmd, OutDir) ->
    %% Obtain all the test modules for inclusion in the compile stage.
    TestErls = rebar_utils:find_files("test", ?RE_PREFIX".*\\.erl\$"),

    ErlOpts = rebar_utils:erl_opts(Config),
    {Config1, ErlOpts1} = test_compile_config_and_opts(Config, ErlOpts, Cmd),

    %% Copy source files to eunit dir for cover in case they are not directly
    %% in src but in a subdirectory of src. Cover only looks in cwd and ../src
    %% for source files. Also copy files from src_dirs.
    SrcDirs = rebar_utils:src_dirs(proplists:append_values(src_dirs, ErlOpts1)),
    SrcErls = lists:foldl(
                fun(Dir, Acc) ->
                        Files = rebar_utils:find_files(
                                  Dir, ?RE_PREFIX".*\\.erl\$"),
                        lists:append(Acc, Files)
                end, [], SrcDirs),

    %% If it is not the first time rebar eunit or rebar qc is executed,
    %% there will be source files already present in Dir. Since some
    %% SCMs (like Perforce) set the source files as being read only (unless
    %% they are checked out), we need to be sure that the files already
    %% present in Dir are writable before doing the copy. This is done
    %% here by removing any file that was already present before calling
    %% rebar_file_utils:cp_r.

    %% Get the full path to a file that was previously copied in OutDir
    ToCleanUp = fun(F, Acc) ->
                        F2 = filename:basename(F),
                        F3 = filename:join([OutDir, F2]),
                        case filelib:is_regular(F3) of
                            true -> [F3|Acc];
                            false -> Acc
                        end
                end,

    ok = rebar_file_utils:delete_each(lists:foldl(ToCleanUp, [], TestErls)),
    ok = rebar_file_utils:delete_each(lists:foldl(ToCleanUp, [], SrcErls)),

    ok = rebar_file_utils:cp_r(SrcErls ++ TestErls, OutDir),

    %% Compile erlang code to OutDir, using a tweaked config
    %% with appropriate defines for eunit, and include all the test modules
    %% as well.
    ok = doterl_compile(Config1, OutDir, TestErls, ErlOpts1),

    {ok, SrcErls}.

%% ===================================================================
%% Internal functions
%% ===================================================================

info(help, compile) ->
    info_help("Build *.erl, *.yrl, *.xrl, and *.mib sources");
info(help, clean) ->
    info_help("Delete *.erl, *.yrl, *.xrl, and *.mib build results").

info_help(Description) ->
    ?CONSOLE(
       "~s.~n"
       "~n"
       "Valid rebar.config options:~n"
       "  ~p~n"
       "  ~p~n"
       "  ~p~n"
       "  ~p~n"
       "  ~p~n"
       "  ~p~n"
       "  ~p~n"
       "  ~p~n",
       [
        Description,
        {erl_opts, [no_debug_info,
                    {i, "myinclude"},
                    {src_dirs, ["src", "src2", "src3"]},
                    {platform_define,
                     "(linux|solaris|freebsd|darwin)", 'HAVE_SENDFILE'},
                    {platform_define, "(linux|freebsd)", 'BACKLOG', 128},
                    {platform_define, "R13", 'old_inets'}]},
        {erl_first_files, ["src/mymib1.erl", "src/mymib2.erl"]},
        {mib_opts, []},
        {mib_first_files, []},
        {xrl_opts, []},
        {xrl_first_files, []},
        {yrl_opts, []},
        {yrl_first_files, []}
       ]).

test_compile_config_and_opts(Config, ErlOpts, Cmd) ->
    {Config1, TriqOpts} = triq_opts(Config),
    {Config2, PropErOpts} = proper_opts(Config1),
    {Config3, EqcOpts} = eqc_opts(Config2),

    %% NOTE: For consistency, all *_first_files lists should be
    %% retrieved via rebar_state:get. Right now
    %% erl_first_files, eunit_first_files, and qc_first_files use
    %% rebar_state:get_list and are inherited, but xrl_first_files
    %% and yrl_first_files use rebar_state:get. Inheritance of
    %% *_first_files is questionable as the file would need to exist
    %% in all project directories for it to work.
    OptsAtom = list_to_atom(Cmd ++ "_compile_opts"),
    TestOpts = rebar_state:get_list(Config3, OptsAtom, []),
    Opts0 = [{d, 'TEST'}] ++
        ErlOpts ++ TestOpts ++ TriqOpts ++ PropErOpts ++ EqcOpts,
    Opts = [O || O <- Opts0, O =/= no_debug_info],
    Config4 = rebar_state:set(Config3, erl_opts, Opts),

    FirstFilesAtom = list_to_atom(Cmd ++ "_first_files"),
    FirstErls = rebar_state:get_list(Config4, FirstFilesAtom, []),
    Config5 = rebar_state:set(Config4, erl_first_files, FirstErls),
    {Config5, Opts}.

triq_opts(Config) ->
    {NewConfig, IsAvail} = is_lib_avail(Config, is_triq_avail, triq,
                                        "triq.hrl", "Triq"),
    Opts = define_if('TRIQ', IsAvail),
    {NewConfig, Opts}.

proper_opts(Config) ->
    {NewConfig, IsAvail} = is_lib_avail(Config, is_proper_avail, proper,
                                        "proper.hrl", "PropEr"),
    Opts = define_if('PROPER', IsAvail),
    {NewConfig, Opts}.

eqc_opts(Config) ->
    {NewConfig, IsAvail} = is_lib_avail(Config, is_eqc_avail, eqc,
                                        "eqc.hrl", "QuickCheck"),
    Opts = define_if('EQC', IsAvail),
    {NewConfig, Opts}.

define_if(Def, true) -> [{d, Def}];
define_if(_Def, false) -> [].

is_lib_avail(Config, DictKey, Mod, Hrl, Name) ->
    case rebar_state:get_xconf(Config, DictKey, undefined) of
        undefined ->
            IsAvail = case code:lib_dir(Mod, include) of
                          {error, bad_name} ->
                              false;
                          Dir ->
                              filelib:is_regular(filename:join(Dir, Hrl))
                      end,
            NewConfig = rebar_state:set_xconf(Config, DictKey, IsAvail),
            ?DEBUG("~s availability: ~p\n", [Name, IsAvail]),
            {NewConfig, IsAvail};
        IsAvail ->
            {Config, IsAvail}
    end.

-spec doterl_compile(rebar_state:t(), file:filename()) -> 'ok'.
doterl_compile(Config, Dir) ->
    ErlOpts = rebar_utils:erl_opts(Config),
    doterl_compile(Config, Dir, [], ErlOpts).

doterl_compile(Config, Dir, MoreSources, ErlOpts) ->
    OutDir = filename:join(Dir, "ebin"),
    ErlFirstFilesConf = rebar_state:get(Config, erl_first_modules, []),
    ?DEBUG("erl_opts ~p~n", [ErlOpts]),
    %% Support the src_dirs option allowing multiple directories to
    %% contain erlang source. This might be used, for example, should
    %% eunit tests be separated from the core application source.
    SrcDirs = lists:map(fun(X) ->
                                filename:join(Dir, X)
                        end, rebar_utils:src_dirs(proplists:append_values(src_dirs, ErlOpts))),
    AllErlFiles = gather_src(SrcDirs, []) ++ MoreSources,
    %% NOTE: If and when erl_first_files is not inherited anymore
    %% (rebar_state:get instead of rebar_state:get_list), consider
    %% logging a warning message for any file listed in erl_first_files which
    %% wasn't found via gather_src.
    {ErlFirstFiles, RestErls} =
        lists:partition(
          fun(Source) ->
                  lists:member(list_to_atom(filename:basename(Source, ".erl")), ErlFirstFilesConf)
          end, AllErlFiles),
    %% Make sure that ebin/ exists and is on the path
    ok = filelib:ensure_dir(filename:join([Dir, "ebin", "dummy.beam"])),
    CurrPath = code:get_path(),
    true = code:add_path(filename:absname(filename:join(Dir, "ebin"))),
    OutDir1 = proplists:get_value(outdir, ErlOpts, OutDir),
    G = init_erlcinfo(Config, AllErlFiles),
    %% Split RestErls so that files which are depended on are treated
    %% like erl_first_files.
    {OtherFirstErls, OtherErls} =
        lists:partition(
          fun(F) ->
                  Children = get_children(G, F),
                  log_files(?FMT("Files dependent on ~s", [F]), Children),

                  case erls(Children) of
                      [] ->
                          %% There are no files dependent on this file.
                          false;
                      _ ->
                          %% There are some files dependent on the file.
                          %% Thus the file has higher priority
                          %% and should be compiled in the first place.
                          true
                  end
          end, RestErls),
    %% Dependencies of OtherFirstErls that must be compiled first.
    OtherFirstErlsDeps = lists:flatmap(
                           fun(Erl) -> erls(get_parents(G, Erl)) end,
                           OtherFirstErls),
    %% NOTE: In case the way we retrieve OtherFirstErlsDeps or merge
    %% it with OtherFirstErls does not result in the correct compile
    %% priorities, or the method in use proves to be too slow for
    %% certain projects, consider using a more elaborate method (maybe
    %% digraph_utils) or alternatively getting and compiling the .erl
    %% parents of an individual Source in internal_erl_compile. By not
    %% handling this in internal_erl_compile, we also avoid extra
    %% needs_compile/2 calls.
    FirstErls = ErlFirstFiles ++ uo_merge(OtherFirstErlsDeps, OtherFirstErls),
    ?DEBUG("Files to compile first: ~p~n", [FirstErls]),
    rebar_base_compiler:run(
      Config, FirstErls, OtherErls,
      fun(S, C) ->
              internal_erl_compile(C, Dir, S, OutDir1, ErlOpts, G)
      end),
    true = code:set_path(CurrPath),
    ok.

%%
%% Return all .erl files from a list of files
%%
erls(Files) ->
    [Erl || Erl <- Files, filename:extension(Erl) =:= ".erl"].

%%
%% Return a list without duplicates while preserving order
%%
ulist(L) ->
    ulist(L, []).

ulist([H|T], Acc) ->
    case lists:member(H, T) of
        true ->
            ulist(T, Acc);
        false ->
            ulist(T, [H|Acc])
    end;
ulist([], Acc) ->
    lists:reverse(Acc).

%%
%% Merge two lists without duplicates while preserving order
%%
uo_merge(L1, L2) ->
    lists:foldl(fun(E, Acc) -> u_add_element(E, Acc) end, ulist(L1), L2).

u_add_element(Elem, [Elem|_]=Set) -> Set;
u_add_element(Elem, [E1|Set])     -> [E1|u_add_element(Elem, Set)];
u_add_element(Elem, [])           -> [Elem].

-spec include_path(file:filename(),
                   rebar_state:t()) -> [file:filename(), ...].
include_path(Source, Config) ->
    ErlOpts = rebar_state:get(Config, erl_opts, []),
    Dir = filename:join(lists:droplast(filename:split(filename:dirname(Source)))),
    lists:usort([filename:join(Dir, "include"), filename:dirname(Source)]
                ++ proplists:get_all_values(i, ErlOpts)).

-spec needs_compile(file:filename(), file:filename(),
                    [string()]) -> boolean().
needs_compile(Source, Target, Parents) ->
    TargetLastMod = filelib:last_modified(Target),
    lists:any(fun(I) -> TargetLastMod < filelib:last_modified(I) end,
              [Source] ++ Parents).

check_erlcinfo(_Config, #erlcinfo{vsn=?ERLCINFO_VSN}) ->
    ok;
check_erlcinfo(Config, #erlcinfo{vsn=Vsn}) ->
    ?ABORT("~s file version is incompatible. expected: ~b got: ~b~n",
           [erlcinfo_file(Config), ?ERLCINFO_VSN, Vsn]);
check_erlcinfo(Config, _) ->
    ?ABORT("~s file is invalid. Please delete before next run.~n",
           [erlcinfo_file(Config)]).

erlcinfo_file(_Config) ->
    filename:join([rebar_utils:get_cwd(), ".rebar", ?ERLCINFO_FILE]).

init_erlcinfo(Config, Erls) ->
    G = restore_erlcinfo(Config),
    %% Get a unique list of dirs based on the source files' locations.
    %% This is used for finding files in sub dirs of the configured
    %% src_dirs. For example, src/sub_dir/foo.erl.
    Dirs = sets:to_list(lists:foldl(
                          fun(Erl, Acc) ->
                                  Dir = filename:dirname(Erl),
                                  sets:add_element(Dir, Acc)
                          end, sets:new(), Erls)),
    Updates = [update_erlcinfo(G, Erl, include_path(Erl, Config) ++ Dirs)
               || Erl <- Erls],
    Modified = lists:member(modified, Updates),
    ok = store_erlcinfo(G, Config, Modified),
    G.

update_erlcinfo(G, Source, Dirs) ->
    case digraph:vertex(G, Source) of
        {_, LastUpdated} ->
            case filelib:last_modified(Source) of
                0 ->
                    %% The file doesn't exist anymore,
                    %% erase it from the graph.
                    %% All the edges will be erased automatically.
                    digraph:del_vertex(G, Source),
                    modified;
                LastModified when LastUpdated < LastModified ->
                    modify_erlcinfo(G, Source, Dirs),
                    modified;
                _ ->
                    unmodified
            end;
        false ->
            modify_erlcinfo(G, Source, Dirs),
            modified
    end.

modify_erlcinfo(G, Source, Dirs) ->
    {ok, Fd} = file:open(Source, [read]),
    Incls = parse_attrs(Fd, []),
    AbsIncls = expand_file_names(Incls, Dirs),
    ok = file:close(Fd),
    LastUpdated = {date(), time()},
    digraph:add_vertex(G, Source, LastUpdated),
    lists:foreach(
      fun(Incl) ->
              update_erlcinfo(G, Incl, Dirs),
              digraph:add_edge(G, Source, Incl)
      end, AbsIncls).

restore_erlcinfo(Config) ->
    File = erlcinfo_file(Config),
    G = digraph:new(),
    case file:read_file(File) of
        {ok, Data} ->
            try binary_to_term(Data) of
                Erlcinfo ->
                    ok = check_erlcinfo(Config, Erlcinfo),
                    #erlcinfo{info=ErlcInfo} = Erlcinfo,
                    {Vs, Es} = ErlcInfo,
                    lists:foreach(
                      fun({V, LastUpdated}) ->
                              digraph:add_vertex(G, V, LastUpdated)
                      end, Vs),
                    lists:foreach(
                      fun({V1, V2}) ->
                              digraph:add_edge(G, V1, V2)
                      end, Es)
            catch
                error:badarg ->
                    ?ERROR(
                       "Failed (binary_to_term) to restore rebar info file."
                       " Discard file.~n", []),
                    ok
            end;
        _Err ->
            ok
    end,
    G.

store_erlcinfo(_G, _Config, _Modified = false) ->
    ok;
store_erlcinfo(G, Config, _Modified) ->
    Vs = lists:map(
           fun(V) ->
                   digraph:vertex(G, V)
           end, digraph:vertices(G)),
    Es = lists:flatmap(
           fun({V, _}) ->
                   lists:map(
                     fun(E) ->
                             {_, V1, V2, _} = digraph:edge(G, E),
                             {V1, V2}
                     end, digraph:out_edges(G, V))
           end, Vs),
    File = erlcinfo_file(Config),
    ok = filelib:ensure_dir(File),
    Data = term_to_binary(#erlcinfo{info={Vs, Es}}, [{compressed, 9}]),
    file:write_file(File, Data).

%% NOTE: If, for example, one of the entries in Files, refers to
%% gen_server.erl, that entry will be dropped. It is dropped because
%% such an entry usually refers to the beam file, and we don't pass a
%% list of OTP src dirs for finding gen_server.erl's full path. Also,
%% if gen_server.erl was modified, it's not rebar's task to compile a
%% new version of the beam file. Therefore, it's reasonable to drop
%% such entries. Also see process_attr(behaviour, Form, Includes).
-spec expand_file_names([file:filename()],
                        [file:filename()]) -> [file:filename()].
expand_file_names(Files, Dirs) ->
    %% We check if Files exist by itself or within the directories
    %% listed in Dirs.
    %% Return the list of files matched.
    lists:flatmap(
      fun(Incl) ->
              case filelib:is_regular(Incl) of
                  true ->
                      [Incl];
                  false ->
                      lists:flatmap(
                        fun(Dir) ->
                                FullPath = filename:join(Dir, Incl),
                                case filelib:is_regular(FullPath) of
                                    true ->
                                        [FullPath];
                                    false ->
                                        []
                                end
                        end, Dirs)
              end
      end, Files).

-spec get_parents(rebar_digraph(), file:filename()) -> [file:filename()].
get_parents(G, Source) ->
    %% Return all files which the Source depends upon.
    digraph_utils:reachable_neighbours([Source], G).

-spec get_children(rebar_digraph(), file:filename()) -> [file:filename()].
get_children(G, Source) ->
    %% Return all files dependent on the Source.
    digraph_utils:reaching_neighbours([Source], G).

-spec internal_erl_compile(rebar_state:t(), file:filename(), file:filename(),
                           file:filename(), list(),
                           rebar_digraph()) -> 'ok' | 'skipped'.
internal_erl_compile(Config, Dir, Source, OutDir, ErlOpts, G) ->
    %% Determine the target name and includes list by inspecting the source file
    Module = filename:basename(Source, ".erl"),
    Parents = get_parents(G, Source),
    log_files(?FMT("Dependencies of ~s", [Source]), Parents),

    %% Construct the target filename
    Target = filename:join([OutDir | string:tokens(Module, ".")]) ++ ".beam",
    ok = filelib:ensure_dir(Target),

    %% If the file needs compilation, based on last mod date of includes or
    %% the target
    case needs_compile(Source, Target, Parents) of
        true ->
            Opts = [{outdir, filename:dirname(Target)}] ++
                ErlOpts ++ [{i, filename:join(Dir, "include")}, return],
            case compile:file(Source, Opts) of
                {ok, _Mod} ->
                    ok;
                {ok, _Mod, Ws} ->
                    rebar_base_compiler:ok_tuple(Config, Source, Ws);
                {error, Es, Ws} ->
                    rebar_base_compiler:error_tuple(Config, Source,
                                                    Es, Ws, Opts)
            end;
        false ->
            skipped
    end.

-spec compile_mib(file:filename(), file:filename(),
                  rebar_state:t()) -> 'ok'.
compile_mib(Source, Target, Config) ->
    ok = rebar_utils:ensure_dir(Target),
    ok = rebar_utils:ensure_dir(filename:join("include", "dummy.hrl")),
    Opts = [{outdir, "priv/mibs"}, {i, ["priv/mibs"]}] ++
        rebar_state:get(Config, mib_opts, []),
    case snmpc:compile(Source, Opts) of
        {ok, _} ->
            Mib = filename:rootname(Target),
            MibToHrlOpts =
                case proplists:get_value(verbosity, Opts, undefined) of
                    undefined ->
                        #options{specific = []};
                    Verbosity ->
                        #options{specific = [{verbosity, Verbosity}]}
                end,
            ok = snmpc:mib_to_hrl(Mib, Mib, MibToHrlOpts),
            Hrl_filename = Mib ++ ".hrl",
            rebar_file_utils:mv(Hrl_filename, "include"),
            ok;
        {error, compilation_failed} ->
            ?FAIL
    end.

-spec compile_xrl(file:filename(), file:filename(),
                  rebar_state:t()) -> 'ok'.
compile_xrl(Source, Target, Config) ->
    Opts = [{scannerfile, Target} | rebar_state:get(Config, xrl_opts, [])],
    compile_xrl_yrl(Config, Source, Target, Opts, leex).

-spec compile_yrl(file:filename(), file:filename(),
                  rebar_state:t()) -> 'ok'.
compile_yrl(Source, Target, Config) ->
    Opts = [{parserfile, Target} | rebar_state:get(Config, yrl_opts, [])],
    compile_xrl_yrl(Config, Source, Target, Opts, yecc).

-spec compile_xrl_yrl(rebar_state:t(), file:filename(),
                      file:filename(), list(), module()) -> 'ok'.
compile_xrl_yrl(Config, Source, Target, Opts, Mod) ->
    case needs_compile(Source, Target, []) of
        true ->
            case Mod:file(Source, Opts ++ [{return, true}]) of
                {ok, _} ->
                    ok;
                {ok, _Mod, Ws} ->
                    rebar_base_compiler:ok_tuple(Config, Source, Ws);
                {error, Es, Ws} ->
                    rebar_base_compiler:error_tuple(Config, Source,
                                                    Es, Ws, Opts)
            end;
        false ->
            skipped
    end.

gather_src([], Srcs) ->
    Srcs;
gather_src([Dir|Rest], Srcs) ->
    gather_src(
      Rest, Srcs ++ rebar_utils:find_files(Dir, ?RE_PREFIX".*\\.erl\$")).

-spec dirs(file:filename()) -> [file:filename()].
dirs(Dir) ->
    [F || F <- filelib:wildcard(filename:join([Dir, "*"])), filelib:is_dir(F)].

-spec delete_dir(file:filename(), [string()]) -> 'ok' | {'error', atom()}.
delete_dir(Dir, []) ->
    file:del_dir(Dir);
delete_dir(Dir, Subdirs) ->
    lists:foreach(fun(D) -> delete_dir(D, dirs(D)) end, Subdirs),
    file:del_dir(Dir).

parse_attrs(Fd, Includes) ->
    case io:parse_erl_form(Fd, "") of
        {ok, Form, _Line} ->
            case erl_syntax:type(Form) of
                attribute ->
                    NewIncludes = process_attr(Form, Includes),
                    parse_attrs(Fd, NewIncludes);
                _ ->
                    parse_attrs(Fd, Includes)
            end;
        {eof, _} ->
            Includes;
        _Err ->
            parse_attrs(Fd, Includes)
    end.

process_attr(Form, Includes) ->
    try
        AttrName = erl_syntax:atom_value(erl_syntax:attribute_name(Form)),
        process_attr(AttrName, Form, Includes)
    catch _:_ ->
            %% TODO: We should probably try to be more specific here
            %% and not suppress all errors.
            Includes
    end.

process_attr(import, Form, Includes) ->
    case erl_syntax_lib:analyze_import_attribute(Form) of
        {Mod, _Funs} ->
            [atom_to_list(Mod) ++ ".erl"|Includes];
        Mod ->
            [atom_to_list(Mod) ++ ".erl"|Includes]
    end;
process_attr(file, Form, Includes) ->
    {File, _} = erl_syntax_lib:analyze_file_attribute(Form),
    [File|Includes];
process_attr(include, Form, Includes) ->
    [FileNode] = erl_syntax:attribute_arguments(Form),
    File = erl_syntax:string_value(FileNode),
    [File|Includes];
process_attr(include_lib, Form, Includes) ->
    [FileNode] = erl_syntax:attribute_arguments(Form),
    RawFile = erl_syntax:string_value(FileNode),
    File = maybe_expand_include_lib_path(RawFile),
    [File|Includes];
process_attr(behaviour, Form, Includes) ->
    [FileNode] = erl_syntax:attribute_arguments(Form),
    File = erl_syntax:atom_name(FileNode) ++ ".erl",
    [File|Includes];
process_attr(compile, Form, Includes) ->
    [Arg] = erl_syntax:attribute_arguments(Form),
    case erl_syntax:concrete(Arg) of
        {parse_transform, Mod} ->
            [atom_to_list(Mod) ++ ".erl"|Includes];
        {core_transform, Mod} ->
            [atom_to_list(Mod) ++ ".erl"|Includes];
        L when is_list(L) ->
            lists:foldl(
              fun({parse_transform, M}, Acc) ->
                      [atom_to_list(M) ++ ".erl"|Acc];
                 ({core_transform, M}, Acc) ->
                      [atom_to_list(M) ++ ".erl"|Acc];
                 (_, Acc) ->
                      Acc
              end, Includes, L)
    end.

%% Given the filename from an include_lib attribute, if the path
%% exists, return unmodified, or else get the absolute ERL_LIBS
%% path.
maybe_expand_include_lib_path(File) ->
    case filelib:is_regular(File) of
        true ->
            File;
        false ->
            expand_include_lib_path(File)
    end.

%% Given a path like "stdlib/include/erl_compile.hrl", return
%% "OTP_INSTALL_DIR/lib/erlang/lib/stdlib-x.y.z/include/erl_compile.hrl".
%% Usually a simple [Lib, SubDir, File1] = filename:split(File) should
%% work, but to not crash when an unusual include_lib path is used,
%% utilize more elaborate logic.
expand_include_lib_path(File) ->
    File1 = filename:basename(File),
    Split = filename:split(filename:dirname(File)),
    Lib = hd(Split),
    SubDir = filename:join(tl(Split)),
    Dir = code:lib_dir(list_to_atom(Lib), list_to_atom(SubDir)),
    filename:join(Dir, File1).

%%
%% Ensure all files in a list are present and abort if one is missing
%%
-spec check_files([file:filename()]) -> [file:filename()].
check_files(FileList) ->
    [check_file(F) || F <- FileList].

check_file(File) ->
    case filelib:is_regular(File) of
        false -> ?ABORT("File ~p is missing, aborting\n", [File]);
        true -> File
    end.

%% Print prefix followed by list of files. If the list is empty, print
%% on the same line, otherwise use a separate line.
log_files(Prefix, Files) ->
    case Files of
        [] ->
            ?DEBUG("~s: ~p~n", [Prefix, Files]);
        _ ->
            ?DEBUG("~s:~n~p~n", [Prefix, Files])
    end.