aboutsummaryrefslogtreecommitdiff
path: root/scripts/ninjatool.py
blob: 627a1cab4570e2d266391611a616e8d7beaff63c (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
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
#! /bin/sh

# Python module for parsing and processing .ninja files.
#
# Author: Paolo Bonzini
#
# Copyright (C) 2019 Red Hat, Inc.


# We don't want to put "#! @PYTHON@" as the shebang and
# make the file executable, so instead we make this a
# Python/shell polyglot.  The first line below starts a
# multiline string literal for Python, while it is just
# ":" for bash.  The closing of the multiline string literal
# is never parsed by bash since it exits before.

'''':
case "$0" in
  /*) me=$0 ;;
  *) me=$(command -v "$0") ;;
esac
python="@PYTHON@"
case $python in
  @*) python=python3 ;;
esac
exec $python "$me" "$@"
exit 1
'''


from collections import namedtuple, defaultdict
import sys
import os
import re
import json
import argparse
import hashlib
import shutil


class InvalidArgumentError(Exception):
    pass

# faster version of os.path.normpath: do nothing unless there is a double
# slash or a "." or ".." component.  The filter does not have to be super
# precise, but it has to be fast.  os.path.normpath is the hottest function
# for ninja2make without this optimization!
if os.path.sep == '/':
    def normpath(path, _slow_re=re.compile('/[./]')):
        return os.path.normpath(path) if _slow_re.search(path) or path[0] == '.' else path
else:
    normpath = os.path.normpath


def sha1_text(text):
    return hashlib.sha1(text.encode()).hexdigest()

# ---- lexer and parser ----

PATH_RE = r"[^$\s:|]+|\$[$ :]|\$[a-zA-Z0-9_-]+|\$\{[a-zA-Z0-9_.-]+\}"

SIMPLE_PATH_RE = re.compile(r"^[^$\s:|]+$")
IDENT_RE = re.compile(r"[a-zA-Z0-9_.-]+$")
STRING_RE = re.compile(r"(" + PATH_RE + r"|[\s:|])(?:\r?\n)?|.")
TOPLEVEL_RE = re.compile(r"([=:#]|\|\|?|^ +|(?:" + PATH_RE + r")+)\s*|.")
VAR_RE=re.compile(r'\$\$|\$\{([^}]*)\}')

BUILD = 1
POOL = 2
RULE = 3
DEFAULT = 4
EQUALS = 5
COLON = 6
PIPE = 7
PIPE2 = 8
IDENT = 9
INCLUDE = 10
INDENT = 11
EOL = 12


class LexerError(Exception):
    pass


class ParseError(Exception):
    pass


class NinjaParserEvents(object):
    def __init__(self, parser):
        self.parser = parser

    def dollar_token(self, word, in_path=False):
        return '$$' if word == '$' else word

    def variable_expansion_token(self, varname):
        return '${%s}' % varname

    def variable(self, name, arg):
        pass

    def begin_file(self):
        pass

    def end_file(self):
        pass

    def end_scope(self):
        pass

    def begin_pool(self, name):
        pass

    def begin_rule(self, name):
        pass

    def begin_build(self, out, iout, rule, in_, iin, orderdep):
        pass

    def default(self, targets):
        pass


class NinjaParser(object):

    InputFile = namedtuple('InputFile', 'filename iter lineno')

    def __init__(self, filename, input):
        self.stack = []
        self.top = None
        self.iter = None
        self.lineno = None
        self.match_keyword = False
        self.push(filename, input)

    def file_changed(self):
        self.iter = self.top.iter
        self.lineno = self.top.lineno
        if self.top.filename is not None:
            os.chdir(os.path.dirname(self.top.filename) or '.')

    def push(self, filename, input):
        if self.top:
            self.top.lineno = self.lineno
            self.top.iter = self.iter
            self.stack.append(self.top)
        self.top = self.InputFile(filename=filename or 'stdin',
                                  iter=self._tokens(input), lineno=0)
        self.file_changed()

    def pop(self):
        if len(self.stack):
            self.top = self.stack[-1]
            self.stack.pop()
            self.file_changed()
        else:
            self.top = self.iter = None

    def next_line(self, input):
        line = next(input).rstrip()
        self.lineno += 1
        while len(line) and line[-1] == '$':
            line = line[0:-1] + next(input).strip()
            self.lineno += 1
        return line

    def print_token(self, tok):
        if tok == EOL:
            return "end of line"
        if tok == BUILD:
            return '"build"'
        if tok == POOL:
            return '"pool"'
        if tok == RULE:
            return '"rule"'
        if tok == DEFAULT:
            return '"default"'
        if tok == EQUALS:
            return '"="'
        if tok == COLON:
            return '":"'
        if tok == PIPE:
            return '"|"'
        if tok == PIPE2:
            return '"||"'
        if tok == INCLUDE:
            return '"include"'
        if tok == IDENT:
            return 'identifier'
        return '"%s"' % tok

    def error(self, msg):
        raise LexerError("%s:%d: %s" % (self.stack[-1].filename, self.lineno, msg))

    def parse_error(self, msg):
        raise ParseError("%s:%d: %s" % (self.stack[-1].filename, self.lineno, msg))

    def expected(self, expected, tok):
        msg = "found %s, expected " % (self.print_token(tok), )
        for i, exp_tok in enumerate(expected):
            if i > 0:
                msg = msg + (' or ' if i == len(expected) - 1 else ', ')
            msg = msg + self.print_token(exp_tok)
        self.parse_error(msg)

    def _variable_tokens(self, value):
        for m in STRING_RE.finditer(value):
            match = m.group(1)
            if not match:
                self.error("unexpected '%s'" % (m.group(0), ))
            yield match

    def _tokens(self, input):
        while True:
            try:
                line = self.next_line(input)
            except StopIteration:
                return
            for m in TOPLEVEL_RE.finditer(line):
                match = m.group(1)
                if not match:
                    self.error("unexpected '%s'" % (m.group(0), ))
                if match == ':':
                    yield COLON
                    continue
                if match == '|':
                    yield PIPE
                    continue
                if match == '||':
                    yield PIPE2
                    continue
                if match[0] == ' ':
                    yield INDENT
                    continue
                if match[0] == '=':
                    yield EQUALS
                    value = line[m.start() + 1:].lstrip()
                    yield from self._variable_tokens(value)
                    break
                if match[0] == '#':
                    break

                # identifier
                if self.match_keyword:
                    if match == 'build':
                        yield BUILD
                        continue
                    if match == 'pool':
                        yield POOL
                        continue
                    if match == 'rule':
                        yield RULE
                        continue
                    if match == 'default':
                        yield DEFAULT
                        continue
                    if match == 'include':
                        filename = line[m.start() + 8:].strip()
                        self.push(filename, open(filename, 'r'))
                        break
                    if match == 'subninja':
                        self.error('subninja is not supported')
                yield match
            yield EOL

    def parse(self, events):
        global_var = True

        def look_for(*expected):
            # The last token in the token stream is always EOL.  This
            # is exploited to avoid catching StopIteration everywhere.
            tok = next(self.iter)
            if tok not in expected:
                self.expected(expected, tok)
            return tok

        def look_for_ident(*expected):
            tok = next(self.iter)
            if isinstance(tok, str):
                if not IDENT_RE.match(tok):
                    self.parse_error('variable expansion not allowed')
            elif tok not in expected:
                self.expected(expected + (IDENT,), tok)
            return tok

        def parse_assignment_rhs(gen, expected, in_path):
            tokens = []
            for tok in gen:
                if not isinstance(tok, str):
                    if tok in expected:
                        break
                    self.expected(expected + (IDENT,), tok)
                if tok[0] != '$':
                    tokens.append(tok)
                elif tok == '$ ' or tok == '$$' or tok == '$:':
                    tokens.append(events.dollar_token(tok[1], in_path))
                else:
                    var = tok[2:-1] if tok[1] == '{' else tok[1:]
                    tokens.append(events.variable_expansion_token(var))
            else:
                # gen must have raised StopIteration
                tok = None

            if tokens:
                # Fast path avoiding str.join()
                value = tokens[0] if len(tokens) == 1 else ''.join(tokens)
            else:
                value = None
            return value, tok

        def look_for_path(*expected):
            # paths in build rules are parsed one space-separated token
            # at a time and expanded
            token = next(self.iter)
            if not isinstance(token, str):
                return None, token
            # Fast path if there are no dollar and variable expansion
            if SIMPLE_PATH_RE.match(token):
                return token, None
            gen = self._variable_tokens(token)
            return parse_assignment_rhs(gen, expected, True)

        def parse_assignment(tok):
            name = tok
            assert isinstance(name, str)
            look_for(EQUALS)
            value, tok = parse_assignment_rhs(self.iter, (EOL,), False)
            assert tok == EOL
            events.variable(name, value)

        def parse_build():
            # parse outputs
            out = []
            iout = []
            while True:
                value, tok = look_for_path(COLON, PIPE)
                if value is None:
                    break
                out.append(value)
            if tok == PIPE:
                while True:
                    value, tok = look_for_path(COLON)
                    if value is None:
                        break
                    iout.append(value)

            # parse rule
            assert tok == COLON
            rule = look_for_ident()

            # parse inputs and dependencies
            in_ = []
            iin = []
            orderdep = []
            while True:
                value, tok = look_for_path(PIPE, PIPE2, EOL)
                if value is None:
                    break
                in_.append(value)
            if tok == PIPE:
                while True:
                    value, tok = look_for_path(PIPE2, EOL)
                    if value is None:
                        break
                    iin.append(value)
            if tok == PIPE2:
                while True:
                    value, tok = look_for_path(EOL)
                    if value is None:
                        break
                    orderdep.append(value)
            assert tok == EOL
            events.begin_build(out, iout, rule, in_, iin, orderdep)
            nonlocal global_var
            global_var = False

        def parse_pool():
            # pool declarations are ignored.  Just gobble all the variables
            ident = look_for_ident()
            look_for(EOL)
            events.begin_pool(ident)
            nonlocal global_var
            global_var = False

        def parse_rule():
            ident = look_for_ident()
            look_for(EOL)
            events.begin_rule(ident)
            nonlocal global_var
            global_var = False

        def parse_default():
            idents = []
            while True:
                ident = look_for_ident(EOL)
                if ident == EOL:
                    break
                idents.append(ident)
            events.default(idents)

        def parse_declaration(tok):
            if tok == EOL:
                return

            nonlocal global_var
            if tok == INDENT:
                if global_var:
                    self.parse_error('indented line outside rule or edge')
                tok = look_for_ident(EOL)
                if tok == EOL:
                    return
                parse_assignment(tok)
                return

            if not global_var:
                events.end_scope()
                global_var = True
            if tok == POOL:
                parse_pool()
            elif tok == BUILD:
                parse_build()
            elif tok == RULE:
                parse_rule()
            elif tok == DEFAULT:
                parse_default()
            elif isinstance(tok, str):
                parse_assignment(tok)
            else:
                self.expected((POOL, BUILD, RULE, INCLUDE, DEFAULT, IDENT), tok)

        events.begin_file()
        while self.iter:
            try:
                self.match_keyword = True
                token = next(self.iter)
                self.match_keyword = False
                parse_declaration(token)
            except StopIteration:
                self.pop()
        events.end_file()


# ---- variable handling ----

def expand(x, rule_vars=None, build_vars=None, global_vars=None):
    if x is None:
        return None
    changed = True
    have_dollar_replacement = False
    while changed:
        changed = False
        matches = list(VAR_RE.finditer(x))
        if not matches:
            break

        # Reverse the match so that expanding later matches does not
        # invalidate m.start()/m.end() for earlier ones.  Do not reduce $$ to $
        # until all variables are dealt with.
        for m in reversed(matches):
            name = m.group(1)
            if not name:
                have_dollar_replacement = True
                continue
            changed = True
            if build_vars and name in build_vars:
                value = build_vars[name]
            elif rule_vars and name in rule_vars:
                value = rule_vars[name]
            elif name in global_vars:
                value = global_vars[name]
            else:
                value = ''
            x = x[:m.start()] + value + x[m.end():]
    return x.replace('$$', '$') if have_dollar_replacement else x


class Scope(object):
    def __init__(self, events):
        self.events = events

    def on_left_scope(self):
        pass

    def on_variable(self, key, value):
        pass


class BuildScope(Scope):
    def __init__(self, events, out, iout, rule, in_, iin, orderdep, rule_vars):
        super().__init__(events)
        self.rule = rule
        self.out = [events.expand_and_normalize(x) for x in out]
        self.in_ = [events.expand_and_normalize(x) for x in in_]
        self.iin = [events.expand_and_normalize(x) for x in iin]
        self.orderdep = [events.expand_and_normalize(x) for x in orderdep]
        self.iout = [events.expand_and_normalize(x) for x in iout]
        self.rule_vars = rule_vars
        self.build_vars = dict()
        self._define_variable('out', ' '.join(self.out))
        self._define_variable('in', ' '.join(self.in_))

    def expand(self, x):
        return self.events.expand(x, self.rule_vars, self.build_vars)

    def on_left_scope(self):
        self.events.variable('out', self.build_vars['out'])
        self.events.variable('in', self.build_vars['in'])
        self.events.end_build(self, self.out, self.iout, self.rule, self.in_,
                              self.iin, self.orderdep)

    def _define_variable(self, key, value):
        # The value has been expanded already, quote it for further
        # expansion from rule variables
        value = value.replace('$', '$$')
        self.build_vars[key] = value

    def on_variable(self, key, value):
        # in and out are at the top of the lookup order and cannot
        # be overridden.  Also, unlike what the manual says, build
        # variables only lookup global variables.  They never lookup
        # rule variables, earlier build variables, or in/out.
        if key not in ('in', 'in_newline', 'out'):
            self._define_variable(key, self.events.expand(value))


class RuleScope(Scope):
    def __init__(self, events, name, vars_dict):
        super().__init__(events)
        self.name = name
        self.vars_dict = vars_dict
        self.generator = False

    def on_left_scope(self):
        self.events.end_rule(self, self.name)

    def on_variable(self, key, value):
        self.vars_dict[key] = value
        if key == 'generator':
            self.generator = True


class NinjaParserEventsWithVars(NinjaParserEvents):
    def __init__(self, parser):
        super().__init__(parser)
        self.rule_vars = defaultdict(lambda: dict())
        self.global_vars = dict()
        self.scope = None

    def variable(self, name, value):
        if self.scope:
            self.scope.on_variable(name, value)
        else:
            self.global_vars[name] = self.expand(value)

    def begin_build(self, out, iout, rule, in_, iin, orderdep):
        if rule != 'phony' and rule not in self.rule_vars:
            self.parser.parse_error("undefined rule '%s'" % rule)

        self.scope = BuildScope(self, out, iout, rule, in_, iin, orderdep, self.rule_vars[rule])

    def begin_pool(self, name):
        # pool declarations are ignored.  Just gobble all the variables
        self.scope = Scope(self)

    def begin_rule(self, name):
        if name in self.rule_vars:
            self.parser.parse_error("duplicate rule '%s'" % name)
        self.scope = RuleScope(self, name, self.rule_vars[name])

    def end_scope(self):
        self.scope.on_left_scope()
        self.scope = None

    # utility functions:

    def expand(self, x, rule_vars=None, build_vars=None):
        return expand(x, rule_vars, build_vars, self.global_vars)

    def expand_and_normalize(self, x):
        return normpath(self.expand(x))

    # extra events not present in the superclass:

    def end_build(self, scope, out, iout, rule, in_, iin, orderdep):
        pass

    def end_rule(self, scope, name):
        pass


# ---- test client that just prints back whatever it parsed  ----

class Writer(NinjaParserEvents):
    ARGS = argparse.ArgumentParser(description='Rewrite input build.ninja to stdout.')

    def __init__(self, output, parser, args):
        super().__init__(parser)
        self.output = output
        self.indent = ''
        self.had_vars = False

    def dollar_token(self, word, in_path=False):
        return '$' + word

    def print(self, *args, **kwargs):
        if len(args):
            self.output.write(self.indent)
        print(*args, **kwargs, file=self.output)

    def variable(self, name, value):
        self.print('%s = %s' % (name, value))
        self.had_vars = True

    def begin_scope(self):
        self.indent = '  '
        self.had_vars = False

    def end_scope(self):
        if self.had_vars:
            self.print()
        self.indent = ''
        self.had_vars = False

    def begin_pool(self, name):
        self.print('pool %s' % name)
        self.begin_scope()

    def begin_rule(self, name):
        self.print('rule %s' % name)
        self.begin_scope()

    def begin_build(self, outputs, implicit_outputs, rule, inputs, implicit, order_only):
        all_outputs = list(outputs)
        all_inputs = list(inputs)

        if implicit:
            all_inputs.append('|')
            all_inputs.extend(implicit)
        if order_only:
            all_inputs.append('||')
            all_inputs.extend(order_only)
        if implicit_outputs:
            all_outputs.append('|')
            all_outputs.extend(implicit_outputs)

        self.print('build %s: %s' % (' '.join(all_outputs),
                                     ' '.join([rule] + all_inputs)))
        self.begin_scope()

    def default(self, targets):
        self.print('default %s' % ' '.join(targets))


# ---- emit compile_commands.json ----

class Compdb(NinjaParserEventsWithVars):
    ARGS = argparse.ArgumentParser(description='Emit compile_commands.json.')
    ARGS.add_argument('rules', nargs='*',
                      help='The ninja rules to emit compilation commands for.')

    def __init__(self, output, parser, args):
        super().__init__(parser)
        self.output = output
        self.rules = args.rules
        self.sep = ''

    def begin_file(self):
        self.output.write('[')
        self.directory = os.getcwd()

    def print_entry(self, **entry):
        entry['directory'] = self.directory
        self.output.write(self.sep + json.dumps(entry))
        self.sep = ',\n'

    def begin_build(self, out, iout, rule, in_, iin, orderdep):
        if in_ and rule in self.rules:
            super().begin_build(out, iout, rule, in_, iin, orderdep)
        else:
            self.scope = Scope(self)

    def end_build(self, scope, out, iout, rule, in_, iin, orderdep):
        self.print_entry(command=scope.expand('${command}'), file=in_[0])

    def end_file(self):
        self.output.write(']\n')


# ---- clean output files ----

class Clean(NinjaParserEventsWithVars):
    ARGS = argparse.ArgumentParser(description='Remove output build files.')
    ARGS.add_argument('-g', dest='generator', action='store_true',
                      help='clean generated files too')

    def __init__(self, output, parser, args):
        super().__init__(parser)
        self.dry_run = args.dry_run
        self.verbose = args.verbose or args.dry_run
        self.generator = args.generator

    def begin_file(self):
        print('Cleaning... ', end=(None if self.verbose else ''), flush=True)
        self.cnt = 0

    def end_file(self):
        print('%d files' % self.cnt)

    def do_clean(self, *files):
        for f in files:
            if self.dry_run:
                if os.path.exists(f):
                    self.cnt += 1
                    print('Would remove ' + f)
                    continue
            else:
                try:
                    if os.path.isdir(f):
                        shutil.rmtree(f)
                    else:
                        os.unlink(f)
                    self.cnt += 1
                    if self.verbose:
                        print('Removed ' + f)
                except FileNotFoundError:
                    pass

    def end_build(self, scope, out, iout, rule, in_, iin, orderdep):
        if rule == 'phony':
            return
        if self.generator:
            rspfile = scope.expand('${rspfile}')
            if rspfile:
                self.do_clean(rspfile)
        if self.generator or not scope.expand('${generator}'):
            self.do_clean(*out, *iout)
            depfile = scope.expand('${depfile}')
            if depfile:
                self.do_clean(depfile)


# ---- convert build.ninja to makefile ----

class Ninja2Make(NinjaParserEventsWithVars):
    ARGS = argparse.ArgumentParser(description='Convert build.ninja to a Makefile.')
    ARGS.add_argument('--clean', dest='emit_clean', action='store_true',
                      help='Emit clean/distclean rules.')
    ARGS.add_argument('--doublecolon', action='store_true',
                      help='Emit double-colon rules for phony targets.')
    ARGS.add_argument('--omit', metavar='TARGET', nargs='+',
                      help='Targets to omit.')

    def __init__(self, output, parser, args):
        super().__init__(parser)
        self.output = output

        self.emit_clean = args.emit_clean
        self.doublecolon = args.doublecolon
        self.omit = set(args.omit)

        if self.emit_clean:
            self.omit.update(['clean', 'distclean'])

        # Lists of targets are kept in memory and emitted only at the
        # end because appending is really inefficient in GNU make.
        # We only do it when it's O(#rules) or O(#variables), but
        # never when it could be O(#targets).
        self.depfiles = list()
        self.rspfiles = list()
        self.build_vars = defaultdict(lambda: dict())
        self.rule_targets = defaultdict(lambda: list())
        self.stamp_targets = defaultdict(lambda: list())
        self.all_outs = set()
        self.all_ins = set()
        self.all_phony = set()
        self.seen_default = False

    def print(self, *args, **kwargs):
        print(*args, **kwargs, file=self.output)

    def dollar_token(self, word, in_path=False):
        if in_path and word == ' ':
            self.parser.parse_error('Make does not support spaces in filenames')
        return '$$' if word == '$' else word

    def print_phony(self, outs, ins):
        targets = ' '.join(outs).replace('$', '$$')
        deps = ' '.join(ins).replace('$', '$$')
        deps = deps.strip()
        if self.doublecolon:
            self.print(targets + '::' + (' ' if deps else '') + deps + ';@:')
        else:
            self.print(targets + ':' + (' ' if deps else '') + deps)
        self.all_phony.update(outs)

    def begin_file(self):
        self.print(r'# This is an automatically generated file, and it shows.')
        self.print(r'ninja-default:')
        self.print(r'.PHONY: ninja-default ninja-clean ninja-distclean')
        if self.emit_clean:
            self.print(r'ninja-clean:: ninja-clean-start; $(if $V,,@)rm -f ${ninja-depfiles}')
            self.print(r'ninja-clean-start:; $(if $V,,@echo Cleaning...)')
            self.print(r'ninja-distclean:: clean; $(if $V,,@)rm -f ${ninja-rspfiles}')
            self.print(r'.PHONY: ninja-clean-start')
            self.print_phony(['clean'], ['ninja-clean'])
            self.print_phony(['distclean'], ['ninja-distclean'])
        self.print(r'vpath')
        self.print(r'NULL :=')
        self.print(r'SPACE := ${NULL} #')
        self.print(r'MAKEFLAGS += -rR')
        self.print(r'define NEWLINE')
        self.print(r'')
        self.print(r'endef')
        self.print(r'.var.in_newline = $(subst $(SPACE),$(NEWLINE),${.var.in})')
        self.print(r"ninja-command = $(if $V,,$(if ${.var.description},@printf '%s\n' '$(subst ','\'',${.var.description})' && ))${.var.command}")
        self.print(r"ninja-command-restat = $(if $V,,$(if ${.var.description},@printf '%s\n' '$(subst ','\'',${.var.description})' && ))${.var.command} && if test -e $(firstword ${.var.out}); then printf '%s\n' ${.var.out} > $@; fi")

    def end_file(self):
        def natural_sort_key(s, _nsre=re.compile('([0-9]+)')):
            return [int(text) if text.isdigit() else text.lower()
                    for text in _nsre.split(s)]

        self.print()
        self.print('ninja-outputdirs :=')
        for rule in self.rule_vars:
            if rule == 'phony':
                continue
            self.print('ninja-targets-%s := %s' % (rule, ' '.join(self.rule_targets[rule])))
            self.print('ninja-stamp-%s := %s' % (rule, ' '.join(self.stamp_targets[rule])))
            self.print('ninja-outputdirs += $(sort $(dir ${ninja-targets-%s}))' % rule)
            self.print()
        self.print('dummy := $(shell mkdir -p . $(sort $(ninja-outputdirs)))')
        self.print('ninja-depfiles :=' + ' '.join(self.depfiles))
        self.print('ninja-rspfiles :=' + ' '.join(self.rspfiles))
        self.print('-include ${ninja-depfiles}')
        self.print()
        for targets in self.build_vars:
            for name, value in self.build_vars[targets].items():
                self.print('%s: private .var.%s := %s' %
                           (targets, name, value.replace('$', '$$')))
            self.print()
        if not self.seen_default:
            default_targets = sorted(self.all_outs - self.all_ins, key=natural_sort_key)
            self.print('ninja-default: ' + ' '.join(default_targets))

        # This is a hack...  Meson declares input meson.build files as
        # phony, because Ninja does not have an equivalent of Make's
        # "path/to/file:" declaration that ignores "path/to/file" even
        # if it is absent.  However, Makefile.ninja wants to depend on
        # build.ninja, which in turn depends on these phony targets which
        # would cause Makefile.ninja to be rebuilt in a loop.
        phony_targets = sorted(self.all_phony - self.all_ins, key=natural_sort_key)
        self.print('.PHONY: ' + ' '.join(phony_targets))

    def variable(self, name, value):
        super().variable(name, value)
        if self.scope is None:
            self.global_vars[name] = self.expand(value)
            self.print('.var.%s := %s' % (name, self.global_vars[name]))

    def begin_build(self, out, iout, rule, in_, iin, orderdep):
        if any(x in self.omit for x in out):
            self.scope = Scope(self)
            return

        super().begin_build(out, iout, rule, in_, iin, orderdep)
        self.current_targets = ' '.join(self.scope.out + self.scope.iout).replace('$', '$$')

    def end_build(self, scope, out, iout, rule, in_, iin, orderdep):
        self.rule_targets[rule] += self.scope.out
        self.rule_targets[rule] += self.scope.iout

        self.all_outs.update(self.scope.iout)
        self.all_outs.update(self.scope.out)
        self.all_ins.update(self.scope.in_)
        self.all_ins.update(self.scope.iin)

        targets = self.current_targets
        self.current_targets = None
        if rule == 'phony':
            # Phony rules treat order-only dependencies as normal deps
            self.print_phony(out + iout, in_ + iin + orderdep)
            return

        inputs = ' '.join(in_ + iin).replace('$', '$$')
        orderonly = ' '.join(orderdep).replace('$', '$$')

        rspfile = scope.expand('${rspfile}')
        if rspfile:
            rspfile_content = scope.expand('${rspfile_content}')
            with open(rspfile, 'w') as f:
                f.write(rspfile_content)
            inputs += ' ' + rspfile
            self.rspfiles.append(rspfile)

        restat = 'restat' in self.scope.build_vars or 'restat' in self.rule_vars[rule]
        depfile = scope.expand('${depfile}')
        build_vars = {
            'command': scope.expand('${command}'),
            'description': scope.expand('${description}'),
            'out': scope.expand('${out}')
        }

        if restat and not depfile:
            if len(out) == 1:
                stamp = out[0] + '.stamp'
            else:
                stamp = '%s@%s.stamp' % (rule, sha1_text(targets)[0:11])
            self.print('%s: %s; @:' % (targets, stamp))
            self.print('%s: %s | %s; ${ninja-command-restat}' % (stamp, inputs, orderonly))
            self.rule_targets[rule].append(stamp)
            self.stamp_targets[rule].append(stamp)
            self.build_vars[stamp] = build_vars
        else:
            self.print('%s: %s | %s; ${ninja-command}' % (targets, inputs, orderonly))
            self.build_vars[targets] = build_vars
            if depfile:
                self.depfiles.append(depfile)

    def end_rule(self, scope, name):
        # Note that the generator pseudo-variable could also be attached
        # to a build block rather than a rule.  This is not handled here
        # in order to reduce the number of "rm" invocations.  However,
        # "ninjatool.py -t clean" does that correctly.
        target = 'distclean' if scope.generator else 'clean'
        self.print('ninja-%s:: ; $(if $V,,@)rm -f ${ninja-stamp-%s}' % (target, name))
        if self.emit_clean:
            self.print('ninja-%s:: ; $(if $V,,@)rm -rf ${ninja-targets-%s}' % (target, name))

    def default(self, targets):
        self.print("ninja-default: " + ' '.join(targets))
        self.seen_default = True


# ---- command line parsing ----

# we cannot use subparsers because tools are chosen through the "-t"
# option.

class ToolAction(argparse.Action):
    def __init__(self, option_strings, dest, choices, metavar='TOOL', nargs=None, **kwargs):
        if nargs is not None:
            raise ValueError("nargs not allowed")
        super().__init__(option_strings, dest, required=True, choices=choices,
                         metavar=metavar, **kwargs)

    def __call__(self, parser, namespace, value, option_string):
        tool = self.choices[value]
        setattr(namespace, self.dest, tool)
        tool.ARGS.prog = '%s %s %s' % (parser.prog, option_string, value)


class ToolHelpAction(argparse.Action):
    def __init__(self, option_strings, dest, nargs=None, **kwargs):
        if nargs is not None:
            raise ValueError("nargs not allowed")
        super().__init__(option_strings, dest, nargs=0, **kwargs)

    def __call__(self, parser, namespace, values, option_string=None):
        if namespace.tool:
            namespace.tool.ARGS.print_help()
        else:
            parser.print_help()
        parser.exit()


tools = {
    'test': Writer,
    'ninja2make': Ninja2Make,
    'compdb': Compdb,
    'clean': Clean,
}

parser = argparse.ArgumentParser(description='Process and transform build.ninja files.',
                                 add_help=False)
parser.add_argument('-C', metavar='DIR', dest='dir', default='.',
                    help='change to DIR before doing anything else')
parser.add_argument('-f', metavar='FILE', dest='file', default='build.ninja',
                    help='specify input build file [default=build.ninja]')
parser.add_argument('-n', dest='dry_run', action='store_true',
                    help='do not actually do anything')
parser.add_argument('-v', dest='verbose', action='store_true',
                    help='be more verbose')

parser.add_argument('-t', dest='tool', choices=tools, action=ToolAction,
                    help='choose the tool to run')
parser.add_argument('-h', '--help', action=ToolHelpAction,
                    help='show this help message and exit')

if len(sys.argv) >= 2 and sys.argv[1] == '--version':
    print('1.8')
    sys.exit(0)

args, tool_args = parser.parse_known_args()
args.tool.ARGS.parse_args(tool_args, args)

os.chdir(args.dir)
with open(args.file, 'r') as f:
    parser = NinjaParser(args.file, f)
    try:
        events = args.tool(sys.stdout, parser, args)
    except InvalidArgumentError as e:
        parser.error(str(e))
    parser.parse(events)