summaryrefslogtreecommitdiffstats
path: root/src/engine/SCons/Script/Main.py
blob: 36dc21e1e41007089f800f020930e4604c3bcc5c (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
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
"""SCons.Script

This file implements the main() function used by the scons script.

Architecturally, this *is* the scons script, and will likely only be
called from the external "scons" wrapper.  Consequently, anything here
should not be, or be considered, part of the build engine.  If it's
something that we expect other software to want to use, it should go in
some other module.  If it's specific to the "scons" script invocation,
it goes here.

"""

#
# __COPYRIGHT__
#
# 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.
#

__revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"

import SCons.compat

import os
import os.path
import string
import sys
import time
import traceback

# Strip the script directory from sys.path() so on case-insensitive
# (Windows) systems Python doesn't think that the "scons" script is the
# "SCons" package.  Replace it with our own version directory so, if
# if they're there, we pick up the right version of the build engine
# modules.
#sys.path = [os.path.join(sys.prefix,
#                         'lib',
#                         'scons-%d' % SCons.__version__)] + sys.path[1:]

import SCons.CacheDir
import SCons.Debug
import SCons.Defaults
import SCons.Environment
import SCons.Errors
import SCons.Job
import SCons.Node
import SCons.Node.FS
import SCons.SConf
import SCons.Script
import SCons.Taskmaster
import SCons.Util
import SCons.Warnings

#

class SConsPrintHelpException(Exception):
    pass

display = SCons.Util.display
progress_display = SCons.Util.DisplayEngine()

first_command_start = None
last_command_end = None

class Progressor:
    prev = ''
    count = 0
    target_string = '$TARGET'

    def __init__(self, obj, interval=1, file=None, overwrite=False):
        if file is None:
            file = sys.stdout

        self.obj = obj
        self.file = file
        self.interval = interval
        self.overwrite = overwrite

        if callable(obj):
            self.func = obj
        elif SCons.Util.is_List(obj):
            self.func = self.spinner
        elif string.find(obj, self.target_string) != -1:
            self.func = self.replace_string
        else:
            self.func = self.string

    def write(self, s):
        self.file.write(s)
        self.file.flush()
        self.prev = s

    def erase_previous(self):
        if self.prev:
            length = len(self.prev)
            if self.prev[-1] in ('\n', '\r'):
                length = length - 1
            self.write(' ' * length + '\r')
            self.prev = ''

    def spinner(self, node):
        self.write(self.obj[self.count % len(self.obj)])

    def string(self, node):
        self.write(self.obj)

    def replace_string(self, node):
        self.write(string.replace(self.obj, self.target_string, str(node)))

    def __call__(self, node):
        self.count = self.count + 1
        if (self.count % self.interval) == 0:
            if self.overwrite:
                self.erase_previous()
            self.func(node)

ProgressObject = SCons.Util.Null()

def Progress(*args, **kw):
    global ProgressObject
    ProgressObject = apply(Progressor, args, kw)

# Task control.
#
class BuildTask(SCons.Taskmaster.Task):
    """An SCons build task."""
    progress = ProgressObject

    def display(self, message):
        display('scons: ' + message)

    def prepare(self):
        self.progress(self.targets[0])
        return SCons.Taskmaster.Task.prepare(self)

    def execute(self):
        for target in self.targets:
            if target.get_state() == SCons.Node.up_to_date: 
                continue
            if target.has_builder() and not hasattr(target.builder, 'status'):
                if print_time:
                    start_time = time.time()
                    global first_command_start
                    if first_command_start is None:
                        first_command_start = start_time
                SCons.Taskmaster.Task.execute(self)
                if print_time:
                    global cumulative_command_time
                    global last_command_end
                    finish_time = time.time()
                    last_command_end = finish_time
                    cumulative_command_time = cumulative_command_time+finish_time-start_time
                    sys.stdout.write("Command execution time: %f seconds\n"%(finish_time-start_time))
                break
        else:
            if self.top and target.has_builder():
                display("scons: `%s' is up to date." % str(self.node))

    def do_failed(self, status=2):
        global exit_status
        if self.options.ignore_errors:
            SCons.Taskmaster.Task.executed(self)
        elif self.options.keep_going:
            SCons.Taskmaster.Task.fail_continue(self)
            exit_status = status
        else:
            SCons.Taskmaster.Task.fail_stop(self)
            exit_status = status
            
    def executed(self):
        t = self.targets[0]
        if self.top and not t.has_builder() and not t.side_effect:
            if not t.exists():
                sys.stderr.write("scons: *** Do not know how to make target `%s'." % t)
                if not self.options.keep_going:
                    sys.stderr.write("  Stop.")
                sys.stderr.write("\n")
                self.do_failed()
            else:
                print "scons: Nothing to be done for `%s'." % t
                SCons.Taskmaster.Task.executed(self)
        else:
            SCons.Taskmaster.Task.executed(self)

    def failed(self):
        # Handle the failure of a build task.  The primary purpose here
        # is to display the various types of Errors and Exceptions
        # appropriately.
        status = 2
        exc_info = self.exc_info()
        try:
            t, e, tb = exc_info
        except ValueError:
            t, e = exc_info
            tb = None
        if t is None:
            # The Taskmaster didn't record an exception for this Task;
            # see if the sys module has one.
            t, e = sys.exc_info()[:2]

        def nodestring(n):
            if not SCons.Util.is_List(n):
                n = [ n ]
            return string.join(map(str, n), ', ')

        errfmt = "scons: *** [%s] %s\n"

        if t == SCons.Errors.BuildError:
            tname = nodestring(e.node)
            errstr = e.errstr
            if e.filename:
                errstr = e.filename + ': ' + errstr
            sys.stderr.write(errfmt % (tname, errstr))
        elif t == SCons.Errors.TaskmasterException:
            tname = nodestring(e.node)
            sys.stderr.write(errfmt % (tname, e.errstr))
            type, value, trace = e.exc_info
            traceback.print_exception(type, value, trace)
        elif t == SCons.Errors.ExplicitExit:
            status = e.status
            tname = nodestring(e.node)
            errstr = 'Explicit exit, status %s' % status
            sys.stderr.write(errfmt % (tname, errstr))
        else:
            if e is None:
                e = t
            s = str(e)
            if t == SCons.Errors.StopError and not self.options.keep_going:
                s = s + '  Stop.'
            sys.stderr.write("scons: *** %s\n" % s)

            if tb and print_stacktrace:
                sys.stderr.write("scons: internal stack trace:\n")
                traceback.print_tb(tb, file=sys.stderr)

        self.do_failed(status)

        self.exc_clear()

    def postprocess(self):
        if self.top:
            t = self.targets[0]
            for tp in self.options.tree_printers:
                tp.display(t)
            if self.options.debug_includes:
                tree = t.render_include_tree()
                if tree:
                    print
                    print tree
        SCons.Taskmaster.Task.postprocess(self)

    def make_ready(self):
        """Make a task ready for execution"""
        SCons.Taskmaster.Task.make_ready(self)
        if self.out_of_date and self.options.debug_explain:
            explanation = self.out_of_date[0].explain()
            if explanation:
                sys.stdout.write("scons: " + explanation)

class CleanTask(SCons.Taskmaster.Task):
    """An SCons clean task."""
    def dir_index(self, directory):
        dirname = lambda f, d=directory: os.path.join(d, f)
        files = map(dirname, os.listdir(directory))

        # os.listdir() isn't guaranteed to return files in any specific order,
        # but some of the test code expects sorted output.
        files.sort()
        return files

    def fs_delete(self, path, remove=1):
        try:
            if os.path.exists(path):
                if os.path.isfile(path):
                    if remove: os.unlink(path)
                    display("Removed " + path)
                elif os.path.isdir(path) and not os.path.islink(path):
                    # delete everything in the dir
                    for p in self.dir_index(path):
                        if os.path.isfile(p):
                            if remove: os.unlink(p)
                            display("Removed " + p)
                        else:
                            self.fs_delete(p, remove)
                    # then delete dir itself
                    if remove: os.rmdir(path)
                    display("Removed directory " + path)
        except (IOError, OSError), e:
            print "scons: Could not remove '%s':" % str(path), e.strerror

    def show(self):
        target = self.targets[0]
        if (target.has_builder() or target.side_effect) and not target.noclean:
            for t in self.targets:
                if not t.isdir():
                    display("Removed " + str(t))
        if SCons.Environment.CleanTargets.has_key(target):
            files = SCons.Environment.CleanTargets[target]
            for f in files:
                self.fs_delete(str(f), 0)

    def remove(self):
        target = self.targets[0]
        if (target.has_builder() or target.side_effect) and not target.noclean:
            for t in self.targets:
                try:
                    removed = t.remove()
                except OSError, e:
                    # An OSError may indicate something like a permissions
                    # issue, an IOError would indicate something like
                    # the file not existing.  In either case, print a
                    # message and keep going to try to remove as many
                    # targets aa possible.
                    print "scons: Could not remove '%s':" % str(t), e.strerror
                else:
                    if removed:
                        display("Removed " + str(t))
        if SCons.Environment.CleanTargets.has_key(target):
            files = SCons.Environment.CleanTargets[target]
            for f in files:
                self.fs_delete(str(f))

    execute = remove

    # We want the Taskmaster to update the Node states (and therefore
    # handle reference counts, etc.), but we don't want to call
    # back to the Node's post-build methods, which would do things
    # we don't want, like store .sconsign information.
    executed = SCons.Taskmaster.Task.executed_without_callbacks

    # Have the taskmaster arrange to "execute" all of the targets, because
    # we'll figure out ourselves (in remove() or show() above) whether
    # anything really needs to be done.
    make_ready = SCons.Taskmaster.Task.make_ready_all

    def prepare(self):
        pass

class QuestionTask(SCons.Taskmaster.Task):
    """An SCons task for the -q (question) option."""
    def prepare(self):
        pass
    
    def execute(self):
        if self.targets[0].get_state() != SCons.Node.up_to_date or \
           (self.top and not self.targets[0].exists()):
            global exit_status
            exit_status = 1
            self.tm.stop()

    def executed(self):
        pass


class TreePrinter:
    def __init__(self, derived=False, prune=False, status=False):
        self.derived = derived
        self.prune = prune
        self.status = status
    def get_all_children(self, node):
        return node.all_children()
    def get_derived_children(self, node):
        children = node.all_children(None)
        return filter(lambda x: x.has_builder(), children)
    def display(self, t):
        if self.derived:
            func = self.get_derived_children
        else:
            func = self.get_all_children
        s = self.status and 2 or 0
        SCons.Util.print_tree(t, func, prune=self.prune, showtags=s)


# Global variables

print_objects = 0
print_memoizer = 0
print_stacktrace = 0
print_time = 0
sconscript_time = 0
cumulative_command_time = 0
exit_status = 0 # exit status, assume success by default
num_jobs = None
delayed_warnings = []

class FakeOptionParser:
    """
    A do-nothing option parser, used for the initial OptionsParser variable.

    During normal SCons operation, the OptionsParser is created right
    away by the main() function.  Certain tests scripts however, can
    introspect on different Tool modules, the initialization of which
    can try to add a new, local option to an otherwise uninitialized
    OptionsParser object.  This allows that introspection to happen
    without blowing up.

    """
    class FakeOptionValues:
        def __getattr__(self, attr):
            return None
    values = FakeOptionValues()
    def add_local_option(self, *args, **kw):
        pass

OptionsParser = FakeOptionParser()

def AddOption(*args, **kw):
    if not kw.has_key('default'):
        kw['default'] = None
    result = apply(OptionsParser.add_local_option, args, kw)
    return result

def GetOption(name):
    return getattr(OptionsParser.values, name)

def SetOption(name, value):
    return OptionsParser.values.set_option(name, value)

#
class Stats:
    def __init__(self):
        self.stats = []
        self.labels = []
        self.append = self.do_nothing
        self.print_stats = self.do_nothing
    def enable(self, outfp):
        self.outfp = outfp
        self.append = self.do_append
        self.print_stats = self.do_print
    def do_nothing(self, *args, **kw):
        pass

class CountStats(Stats):
    def do_append(self, label):
        self.labels.append(label)
        self.stats.append(SCons.Debug.fetchLoggedInstances())
    def do_print(self):
        stats_table = {}
        for s in self.stats:
            for n in map(lambda t: t[0], s):
                stats_table[n] = [0, 0, 0, 0]
        i = 0
        for s in self.stats:
            for n, c in s:
                stats_table[n][i] = c
            i = i + 1
        keys = stats_table.keys()
        keys.sort()
        self.outfp.write("Object counts:\n")
        pre = ["   "]
        post = ["   %s\n"]
        l = len(self.stats)
        fmt1 = string.join(pre + [' %7s']*l + post, '')
        fmt2 = string.join(pre + [' %7d']*l + post, '')
        labels = self.labels[:l]
        labels.append(("", "Class"))
        self.outfp.write(fmt1 % tuple(map(lambda x: x[0], labels)))
        self.outfp.write(fmt1 % tuple(map(lambda x: x[1], labels)))
        for k in keys:
            r = stats_table[k][:l] + [k]
            self.outfp.write(fmt2 % tuple(r))

count_stats = CountStats()

class MemStats(Stats):
    def do_append(self, label):
        self.labels.append(label)
        self.stats.append(SCons.Debug.memory())
    def do_print(self):
        fmt = 'Memory %-32s %12d\n'
        for label, stats in map(None, self.labels, self.stats):
            self.outfp.write(fmt % (label, stats))

memory_stats = MemStats()

# utility functions

def _scons_syntax_error(e):
    """Handle syntax errors. Print out a message and show where the error
    occurred.
    """
    etype, value, tb = sys.exc_info()
    lines = traceback.format_exception_only(etype, value)
    for line in lines:
        sys.stderr.write(line+'\n')
    sys.exit(2)

def find_deepest_user_frame(tb):
    """
    Find the deepest stack frame that is not part of SCons.

    Input is a "pre-processed" stack trace in the form
    returned by traceback.extract_tb() or traceback.extract_stack()
    """
    
    tb.reverse()

    # find the deepest traceback frame that is not part
    # of SCons:
    for frame in tb:
        filename = frame[0]
        if string.find(filename, os.sep+'SCons'+os.sep) == -1:
            return frame
    return tb[0]

def _scons_user_error(e):
    """Handle user errors. Print out a message and a description of the
    error, along with the line number and routine where it occured. 
    The file and line number will be the deepest stack frame that is
    not part of SCons itself.
    """
    global print_stacktrace
    etype, value, tb = sys.exc_info()
    if print_stacktrace:
        traceback.print_exception(etype, value, tb)
    filename, lineno, routine, dummy = find_deepest_user_frame(traceback.extract_tb(tb))
    sys.stderr.write("\nscons: *** %s\n" % value)
    sys.stderr.write('File "%s", line %d, in %s\n' % (filename, lineno, routine))
    sys.exit(2)

def _scons_user_warning(e):
    """Handle user warnings. Print out a message and a description of
    the warning, along with the line number and routine where it occured.
    The file and line number will be the deepest stack frame that is
    not part of SCons itself.
    """
    etype, value, tb = sys.exc_info()
    filename, lineno, routine, dummy = find_deepest_user_frame(traceback.extract_tb(tb))
    sys.stderr.write("\nscons: warning: %s\n" % e)
    sys.stderr.write('File "%s", line %d, in %s\n' % (filename, lineno, routine))

def _scons_internal_warning(e):
    """Slightly different from _scons_user_warning in that we use the
    *current call stack* rather than sys.exc_info() to get our stack trace.
    This is used by the warnings framework to print warnings."""
    filename, lineno, routine, dummy = find_deepest_user_frame(traceback.extract_stack())
    sys.stderr.write("\nscons: warning: %s\n" % e[0])
    sys.stderr.write('File "%s", line %d, in %s\n' % (filename, lineno, routine))

def _scons_internal_error():
    """Handle all errors but user errors. Print out a message telling
    the user what to do in this case and print a normal trace.
    """
    print 'internal error'
    traceback.print_exc()
    sys.exit(2)

def _setup_warn(arg):
    """The --warn option.  An argument to this option
    should be of the form <warning-class> or no-<warning-class>.
    The warning class is munged in order to get an actual class
    name from the SCons.Warnings module to enable or disable.
    The supplied <warning-class> is split on hyphens, each element
    is captialized, then smushed back together.  Then the string
    "SCons.Warnings." is added to the front and "Warning" is added
    to the back to get the fully qualified class name.

    For example, --warn=deprecated will enable the
    SCons.Warnings.DeprecatedWarning class.

    --warn=no-dependency will disable the
    SCons.Warnings.DependencyWarning class.

    As a special case, --warn=all and --warn=no-all
    will enable or disable (respectively) the base
    class of all warnings, which is SCons.Warning.Warning."""

    elems = string.split(string.lower(arg), '-')
    enable = 1
    if elems[0] == 'no':
        enable = 0
        del elems[0]

    if len(elems) == 1 and elems[0] == 'all':
        class_name = "Warning"
    else:
        def _capitalize(s):
            if s[:5] == "scons":
                return "SCons" + s[5:]
            else:
                return string.capitalize(s)
        class_name = string.join(map(_capitalize, elems), '') + "Warning"
    try:
        clazz = getattr(SCons.Warnings, class_name)
    except AttributeError:
        sys.stderr.write("No warning type: '%s'\n" % arg)
    else:
        if enable:
            SCons.Warnings.enableWarningClass(clazz)
        else:
            SCons.Warnings.suppressWarningClass(clazz)

def _SConstruct_exists(dirname='', repositories=[]):
    """This function checks that an SConstruct file exists in a directory.
    If so, it returns the path of the file. By default, it checks the
    current directory.
    """
    for file in ['SConstruct', 'Sconstruct', 'sconstruct']:
        sfile = os.path.join(dirname, file)
        if os.path.isfile(sfile):
            return sfile
        if not os.path.isabs(sfile):
            for rep in repositories:
                if os.path.isfile(os.path.join(rep, sfile)):
                    return sfile
    return None

def _set_debug_values(options):
    global print_memoizer, print_objects, print_stacktrace, print_time

    debug_values = options.debug

    if "count" in debug_values:
        # All of the object counts are within "if __debug__:" blocks,
        # which get stripped when running optimized (with python -O or
        # from compiled *.pyo files).  Provide a warning if __debug__ is
        # stripped, so it doesn't just look like --debug=count is broken.
        enable_count = False
        if __debug__: enable_count = True
        if enable_count:
            count_stats.enable(sys.stdout)
        else:
            msg = "--debug=count is not supported when running SCons\n" + \
                  "\twith the python -O option or optimized (.pyo) modules."
            SCons.Warnings.warn(SCons.Warnings.NoObjectCountWarning, msg)
    if "dtree" in debug_values:
        options.tree_printers.append(TreePrinter(derived=True))
    options.debug_explain = ("explain" in debug_values)
    if "findlibs" in debug_values:
        SCons.Scanner.Prog.print_find_libs = "findlibs"
    options.debug_includes = ("includes" in debug_values)
    print_memoizer = ("memoizer" in debug_values)
    if "memory" in debug_values:
        memory_stats.enable(sys.stdout)
    print_objects = ("objects" in debug_values)
    if "presub" in debug_values:
        SCons.Action.print_actions_presub = 1
    if "stacktrace" in debug_values:
        print_stacktrace = 1
    if "stree" in debug_values:
        options.tree_printers.append(TreePrinter(status=True))
    if "time" in debug_values:
        print_time = 1
    if "tree" in debug_values:
        options.tree_printers.append(TreePrinter())

def _create_path(plist):
    path = '.'
    for d in plist:
        if os.path.isabs(d):
            path = d
        else:
            path = path + '/' + d
    return path

def _load_site_scons_dir(topdir, site_dir_name=None):
    """Load the site_scons dir under topdir.
    Adds site_scons to sys.path, imports site_scons/site_init.py,
    and adds site_scons/site_tools to default toolpath."""
    if site_dir_name:
        err_if_not_found = True       # user specified: err if missing
    else:
        site_dir_name = "site_scons"
        err_if_not_found = False
        
    site_dir = os.path.join(topdir.path, site_dir_name)
    if not os.path.exists(site_dir):
        if err_if_not_found:
            raise SCons.Errors.UserError, "site dir %s not found."%site_dir
        return

    site_init_filename = "site_init.py"
    site_init_modname = "site_init"
    site_tools_dirname = "site_tools"
    sys.path = [os.path.abspath(site_dir)] + sys.path
    site_init_file = os.path.join(site_dir, site_init_filename)
    site_tools_dir = os.path.join(site_dir, site_tools_dirname)
    if os.path.exists(site_init_file):
        import imp
        try:
            fp, pathname, description = imp.find_module(site_init_modname,
                                                        [site_dir])
            try:
                imp.load_module(site_init_modname, fp, pathname, description)
            finally:
                if fp:
                    fp.close()
        except ImportError, e:
            sys.stderr.write("Can't import site init file '%s': %s\n"%(site_init_file, e))
            raise
        except Exception, e:
            sys.stderr.write("Site init file '%s' raised exception: %s\n"%(site_init_file, e))
            raise
    if os.path.exists(site_tools_dir):
        SCons.Tool.DefaultToolpath.append(os.path.abspath(site_tools_dir))

def version_string(label, module):
    version = module.__version__
    build = module.__build__
    if build:
        if build[0] != '.':
            build = '.' + build
        version = version + build
    fmt = "\t%s: v%s, %s, by %s on %s\n"
    return fmt % (label,
                  version,
                  module.__date__,
                  module.__developer__,
                  module.__buildsys__)

def _main(parser):
    global exit_status

    options = parser.values

    # Here's where everything really happens.

    # First order of business:  set up default warnings and then
    # handle the user's warning options, so that we can issue (or
    # suppress) appropriate warnings about anything that might happen,
    # as configured by the user.

    default_warnings = [ SCons.Warnings.CorruptSConsignWarning,
                         SCons.Warnings.DeprecatedWarning,
                         SCons.Warnings.DuplicateEnvironmentWarning,
                         SCons.Warnings.MissingSConscriptWarning,
                         SCons.Warnings.NoMD5ModuleWarning,
                         SCons.Warnings.NoMetaclassSupportWarning,
                         SCons.Warnings.NoObjectCountWarning,
                         SCons.Warnings.NoParallelSupportWarning,
                         SCons.Warnings.MisleadingKeywordsWarning, ]
    for warning in default_warnings:
        SCons.Warnings.enableWarningClass(warning)
    SCons.Warnings._warningOut = _scons_internal_warning
    if options.warn:
        _setup_warn(options.warn)

    # Now that we have the warnings configuration set up, we can actually
    # issue (or suppress) any warnings about warning-worthy things that
    # occurred while the command-line options were getting parsed.
    try:
        dw = options.delayed_warnings
    except AttributeError:
        pass
    else:
        delayed_warnings.extend(dw)
    for warning_type, message in delayed_warnings:
        SCons.Warnings.warn(warning_type, message)

    if options.diskcheck:
        SCons.Node.FS.set_diskcheck(options.diskcheck)

    # Next, we want to create the FS object that represents the outside
    # world's file system, as that's central to a lot of initialization.
    # To do this, however, we need to be in the directory from which we
    # want to start everything, which means first handling any relevant
    # options that might cause us to chdir somewhere (-C, -D, -U, -u).
    if options.directory:
        cdir = _create_path(options.directory)
        try:
            os.chdir(cdir)
        except OSError:
            sys.stderr.write("Could not change directory to %s\n" % cdir)

    target_top = None
    if options.climb_up:
        target_top = '.'  # directory to prepend to targets
        script_dir = os.getcwd()  # location of script
        while script_dir and not _SConstruct_exists(script_dir, options.repository):
            script_dir, last_part = os.path.split(script_dir)
            if last_part:
                target_top = os.path.join(last_part, target_top)
            else:
                script_dir = ''
        if script_dir:
            display("scons: Entering directory `%s'" % script_dir)
            os.chdir(script_dir)

    # Now that we're in the top-level SConstruct directory, go ahead
    # and initialize the FS object that represents the file system,
    # and make it the build engine default.
    fs = SCons.Node.FS.get_default_fs()

    for rep in options.repository:
        fs.Repository(rep)

    # Now that we have the FS object, the next order of business is to
    # check for an SConstruct file (or other specified config file).
    # If there isn't one, we can bail before doing any more work.
    scripts = []
    if options.file:
        scripts.extend(options.file)
    if not scripts:
        sfile = _SConstruct_exists(repositories=options.repository)
        if sfile:
            scripts.append(sfile)

    if not scripts:
        if options.help:
            # There's no SConstruct, but they specified -h.
            # Give them the options usage now, before we fail
            # trying to read a non-existent SConstruct file.
            raise SConsPrintHelpException
        raise SCons.Errors.UserError, "No SConstruct file found."

    if scripts[0] == "-":
        d = fs.getcwd()
    else:
        d = fs.File(scripts[0]).dir
    fs.set_SConstruct_dir(d)

    _set_debug_values(options)
    SCons.Node.implicit_cache = options.implicit_cache
    SCons.Node.implicit_deps_changed = options.implicit_deps_changed
    SCons.Node.implicit_deps_unchanged = options.implicit_deps_unchanged
    if options.no_exec:
        SCons.SConf.dryrun = 1
        SCons.Action.execute_actions = None
        CleanTask.execute = CleanTask.show
    if options.question:
        SCons.SConf.dryrun = 1
    if options.clean or options.help:
        # If they're cleaning targets or have asked for help, replace
        # the whole SCons.SConf module with a Null object so that the
        # Configure() calls when reading the SConscript files don't
        # actually do anything.
        SCons.SConf.SConf = SCons.Util.Null
    SCons.SConf.SetCacheMode(options.config)
    SCons.SConf.SetProgressDisplay(progress_display)

    if options.no_progress or options.silent:
        progress_display.set_mode(0)
    if options.silent:
        display.set_mode(0)
    if options.silent:
        SCons.Action.print_actions = None

    if options.cache_disable:
        SCons.CacheDir.CacheDir = SCons.Util.Null()
    if options.cache_debug:
        SCons.CacheDir.cache_debug = options.cache_debug
    if options.cache_force:
        SCons.CacheDir.cache_force = True
    if options.cache_show:
        SCons.CacheDir.cache_show = True

    if options.site_dir:
        _load_site_scons_dir(d, options.site_dir)
    elif not options.no_site_dir:
        _load_site_scons_dir(d)
        
    if options.include_dir:
        sys.path = options.include_dir + sys.path

    # That should cover (most of) the options.  Next, set up the variables
    # that hold command-line arguments, so the SConscript files that we
    # read and execute have access to them.
    targets = []
    xmit_args = []
    for a in parser.largs:
        if a[0] == '-':
            continue
        if '=' in a:
            xmit_args.append(a)
        else:
            targets.append(a)
    SCons.Script._Add_Targets(targets + parser.rargs)
    SCons.Script._Add_Arguments(xmit_args)

    sys.stdout = SCons.Util.Unbuffered(sys.stdout)

    memory_stats.append('before reading SConscript files:')
    count_stats.append(('pre-', 'read'))

    # And here's where we (finally) read the SConscript files.

    progress_display("scons: Reading SConscript files ...")

    start_time = time.time()
    try:
        for script in scripts:
            SCons.Script._SConscript._SConscript(fs, script)
    except SCons.Errors.StopError, e:
        # We had problems reading an SConscript file, such as it
        # couldn't be copied in to the BuildDir.  Since we're just
        # reading SConscript files and haven't started building
        # things yet, stop regardless of whether they used -i or -k
        # or anything else.
        sys.stderr.write("scons: *** %s  Stop.\n" % e)
        exit_status = 2
        sys.exit(exit_status)
    global sconscript_time
    sconscript_time = time.time() - start_time

    progress_display("scons: done reading SConscript files.")

    memory_stats.append('after reading SConscript files:')
    count_stats.append(('post-', 'read'))

    if not options.help:
        SCons.SConf.CreateConfigHBuilder(SCons.Defaults.DefaultEnvironment())

    # Now re-parse the command-line options (any to the left of a '--'
    # argument, that is) with any user-defined command-line options that
    # the SConscript files may have added to the parser object.  This will
    # emit the appropriate error message and exit if any unknown option
    # was specified on the command line.

    parser.preserve_unknown_options = False
    parser.parse_args(parser.largs, options)

    if options.help:
        help_text = SCons.Script.help_text
        if help_text is None:
            # They specified -h, but there was no Help() inside the
            # SConscript files.  Give them the options usage.
            raise SConsPrintHelpException
        else:
            print help_text
            print "Use scons -H for help about command-line options."
        exit_status = 0
        return

    # Change directory to the top-level SConstruct directory, then tell
    # the Node.FS subsystem that we're all done reading the SConscript
    # files and calling Repository() and BuildDir() and changing
    # directories and the like, so it can go ahead and start memoizing
    # the string values of file system nodes.

    fs.chdir(fs.Top)

    SCons.Node.FS.save_strings(1)

    # Now that we've read the SConscripts we can set the options
    # that are SConscript settable:
    SCons.Node.implicit_cache = options.implicit_cache
    SCons.Node.FS.set_duplicate(options.duplicate)
    fs.set_max_drift(options.max_drift)

    lookup_top = None
    if targets or SCons.Script.BUILD_TARGETS != SCons.Script._build_plus_default:
        # They specified targets on the command line or modified
        # BUILD_TARGETS in the SConscript file(s), so if they used -u,
        # -U or -D, we have to look up targets relative to the top,
        # but we build whatever they specified.
        if target_top:
            lookup_top = fs.Dir(target_top)
            target_top = None

        targets = SCons.Script.BUILD_TARGETS
    else:
        # There are no targets specified on the command line,
        # so if they used -u, -U or -D, we may have to restrict
        # what actually gets built.
        d = None
        if target_top:
            if options.climb_up == 1:
                # -u, local directory and below
                target_top = fs.Dir(target_top)
                lookup_top = target_top
            elif options.climb_up == 2:
                # -D, all Default() targets
                target_top = None
                lookup_top = None
            elif options.climb_up == 3:
                # -U, local SConscript Default() targets
                target_top = fs.Dir(target_top)
                def check_dir(x, target_top=target_top):
                    if hasattr(x, 'cwd') and not x.cwd is None:
                        cwd = x.cwd.srcnode()
                        return cwd == target_top
                    else:
                        # x doesn't have a cwd, so it's either not a target,
                        # or not a file, so go ahead and keep it as a default
                        # target and let the engine sort it out:
                        return 1                
                d = filter(check_dir, SCons.Script.DEFAULT_TARGETS)
                SCons.Script.DEFAULT_TARGETS[:] = d
                target_top = None
                lookup_top = None

        targets = SCons.Script._Get_Default_Targets(d, fs)

    if not targets:
        sys.stderr.write("scons: *** No targets specified and no Default() targets found.  Stop.\n")
        sys.exit(2)

    def Entry(x, ltop=lookup_top, ttop=target_top, fs=fs):
        if isinstance(x, SCons.Node.Node):
            node = x
        else:
            node = None
            # Why would ltop be None? Unfortunately this happens.
            if ltop == None: ltop = ''
            # Curdir becomes important when SCons is called with -u, -C,
            # or similar option that changes directory, and so the paths
            # of targets given on the command line need to be adjusted.
            curdir = os.path.join(os.getcwd(), str(ltop))
            for lookup in SCons.Node.arg2nodes_lookups:
                node = lookup(x, curdir=curdir)
                if node != None:
                    break
            if node is None:
                node = fs.Entry(x, directory=ltop, create=1)
        if ttop and not node.is_under(ttop):
            if isinstance(node, SCons.Node.FS.Dir) and ttop.is_under(node):
                node = ttop
            else:
                node = None
        return node

    nodes = filter(None, map(Entry, targets))

    task_class = BuildTask      # default action is to build targets
    opening_message = "Building targets ..."
    closing_message = "done building targets."
    if options.keep_going:
        failure_message = "done building targets (errors occurred during build)."
    else:
        failure_message = "building terminated because of errors."
    if options.question:
        task_class = QuestionTask
    try:
        if options.clean:
            task_class = CleanTask
            opening_message = "Cleaning targets ..."
            closing_message = "done cleaning targets."
            if options.keep_going:
                closing_message = "done cleaning targets (errors occurred during clean)."
            else:
                failure_message = "cleaning terminated because of errors."
    except AttributeError:
        pass

    task_class.progress = ProgressObject

    if options.random:
        def order(dependencies):
            """Randomize the dependencies."""
            import random
            # This is cribbed from the implementation of
            # random.shuffle() in Python 2.X.
            d = dependencies
            for i in xrange(len(d)-1, 0, -1):
                j = int(random.random() * (i+1))
                d[i], d[j] = d[j], d[i]
            return d
    else:
        def order(dependencies):
            """Leave the order of dependencies alone."""
            return dependencies

    progress_display("scons: " + opening_message)
    if options.taskmastertrace_file == '-':
        tmtrace = sys.stdout
    elif options.taskmastertrace_file:
        tmtrace = open(options.taskmastertrace_file, 'wb')
    else:
        tmtrace = None
    taskmaster = SCons.Taskmaster.Taskmaster(nodes, task_class, order, tmtrace)

    # Let the BuildTask objects get at the options to respond to the
    # various print_* settings, tree_printer list, etc.
    BuildTask.options = options

    global num_jobs
    num_jobs = options.num_jobs
    jobs = SCons.Job.Jobs(num_jobs, taskmaster)
    if num_jobs > 1 and jobs.num_jobs == 1:
        msg = "parallel builds are unsupported by this version of Python;\n" + \
              "\tignoring -j or num_jobs option.\n"
        SCons.Warnings.warn(SCons.Warnings.NoParallelSupportWarning, msg)

    memory_stats.append('before building targets:')
    count_stats.append(('pre-', 'build'))

    try:
        jobs.run()
    finally:
        jobs.cleanup()
        if exit_status:
            progress_display("scons: " + failure_message)
        else:
            progress_display("scons: " + closing_message)
        if not options.no_exec:
            SCons.SConsign.write()

    memory_stats.append('after building targets:')
    count_stats.append(('post-', 'build'))

def _exec_main(parser, values):
    sconsflags = os.environ.get('SCONSFLAGS', '')
    all_args = string.split(sconsflags) + sys.argv[1:]

    options, args = parser.parse_args(all_args, values)

    if type(options.debug) == type([]) and "pdb" in options.debug:
        import pdb
        pdb.Pdb().runcall(_main, parser)
    elif options.profile_file:
        from profile import Profile

        # Some versions of Python 2.4 shipped a profiler that had the
        # wrong 'c_exception' entry in its dispatch table.  Make sure
        # we have the right one.  (This may put an unnecessary entry
        # in the table in earlier versions of Python, but its presence
        # shouldn't hurt anything).
        try:
            dispatch = Profile.dispatch
        except AttributeError:
            pass
        else:
            dispatch['c_exception'] = Profile.trace_dispatch_return

        prof = Profile()
        try:
            prof.runcall(_main, parser)
        except SConsPrintHelpException, e:
            prof.dump_stats(options.profile_file)
            raise e
        except SystemExit:
            pass
        prof.dump_stats(options.profile_file)
    else:
        _main(parser)

def main():
    global OptionsParser
    global exit_status
    global first_command_start

    parts = ["SCons by Steven Knight et al.:\n"]
    try:
        parts.append(version_string("script", __main__))
    except KeyboardInterrupt:
        raise
    except:
        # On Windows there is no scons.py, so there is no
        # __main__.__version__, hence there is no script version.
        pass 
    parts.append(version_string("engine", SCons))
    parts.append("__COPYRIGHT__")
    version = string.join(parts, '')

    import SConsOptions
    parser = SConsOptions.Parser(version)
    values = SConsOptions.SConsValues(parser.get_default_values())

    OptionsParser = parser
    
    try:
        _exec_main(parser, values)
    except SystemExit, s:
        if s:
            exit_status = s
    except KeyboardInterrupt:
        print "Build interrupted."
        sys.exit(2)
    except SyntaxError, e:
        _scons_syntax_error(e)
    except SCons.Errors.InternalError:
        _scons_internal_error()
    except SCons.Errors.UserError, e:
        _scons_user_error(e)
    except SConsPrintHelpException:
        parser.print_help()
        exit_status = 0
    except:
        # An exception here is likely a builtin Python exception Python
        # code in an SConscript file.  Show them precisely what the
        # problem was and where it happened.
        SCons.Script._SConscript.SConscript_exception()
        sys.exit(2)

    memory_stats.print_stats()
    count_stats.print_stats()

    if print_objects:
        SCons.Debug.listLoggedInstances('*')
        #SCons.Debug.dumpLoggedInstances('*')

    if print_memoizer:
        SCons.Memoize.Dump("Memoizer (memory cache) hits and misses:")

    # Dump any development debug info that may have been enabled.
    # These are purely for internal debugging during development, so
    # there's no need to control them with --debug= options; they're
    # controlled by changing the source code.
    SCons.Debug.dump_caller_counts()
    SCons.Taskmaster.dump_stats()

    if print_time:
        total_time = time.time() - SCons.Script.start_time
        if num_jobs == 1:
            ct = cumulative_command_time
        else:
            if last_command_end is None or first_command_start is None:
                ct = 0.0
            else:
                ct = last_command_end - first_command_start
        scons_time = total_time - sconscript_time - ct
        print "Total build time: %f seconds"%total_time
        print "Total SConscript file execution time: %f seconds"%sconscript_time
        print "Total SCons execution time: %f seconds"%scons_time
        print "Total command execution time: %f seconds"%ct

    sys.exit(exit_status)