summaryrefslogtreecommitdiffstats
path: root/bitbake/lib/bb/runqueue.py
blob: c5f4380c8615419f8c2d1d76b6c6f7314cfbf6d4 (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
#!/usr/bin/env python
# ex:ts=4:sw=4:sts=4:et
# -*- tab-width: 4; c-basic-offset: 4; indent-tabs-mode: nil -*-
"""
BitBake 'RunQueue' implementation

Handles preparation and execution of a queue of tasks
"""

# Copyright (C) 2006-2007  Richard Purdie
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

from bb import msg, data, event, mkdirhier, utils
import bb, os, sys
import signal
import stat
import fcntl

class TaskFailure(Exception):
    """Exception raised when a task in a runqueue fails"""
    def __init__(self, x): 
        self.args = x


class RunQueueStats:
    """
    Holds statistics on the tasks handled by the associated runQueue
    """
    def __init__(self, total):
        self.completed = 0
        self.skipped = 0
        self.failed = 0
        self.active = 0
        self.total = total

    def taskFailed(self):
        self.active = self.active - 1
        self.failed = self.failed + 1

    def taskCompleted(self, number = 1):
        self.active = self.active - number
        self.completed = self.completed + number

    def taskSkipped(self, number = 1):
        self.active = self.active + number
        self.skipped = self.skipped + number

    def taskActive(self):
        self.active = self.active + 1

# These values indicate the next step due to be run in the 
# runQueue state machine
runQueuePrepare = 2
runQueueRunInit = 3
runQueueRunning = 4
runQueueFailed = 6
runQueueCleanUp = 7
runQueueComplete = 8
runQueueChildProcess = 9

class RunQueueScheduler:
    """
    Control the order tasks are scheduled in.
    """
    def __init__(self, runqueue):
        """
        The default scheduler just returns the first buildable task (the 
        priority map is sorted by task numer)
        """
        self.rq = runqueue
        numTasks = len(self.rq.runq_fnid)

        self.prio_map = []
        self.prio_map.extend(range(numTasks))

    def next(self):
        """
        Return the id of the first task we find that is buildable
        """
        for task1 in range(len(self.rq.runq_fnid)):
            task = self.prio_map[task1]
            if self.rq.runq_running[task] == 1:
                continue
            if self.rq.runq_buildable[task] == 1:
                return task

class RunQueueSchedulerSpeed(RunQueueScheduler):
    """
    A scheduler optimised for speed. The priority map is sorted by task weight,
    heavier weighted tasks (tasks needed by the most other tasks) are run first.
    """
    def __init__(self, runqueue):
        """
        The priority map is sorted by task weight.
        """
        from copy import deepcopy

        self.rq = runqueue

        sortweight = deepcopy(self.rq.runq_weight)
        sortweight.sort()
        copyweight = deepcopy(self.rq.runq_weight)
        self.prio_map = []

        for weight in sortweight:
            idx = copyweight.index(weight)
            self.prio_map.append(idx)
            copyweight[idx] = -1

        self.prio_map.reverse()

class RunQueueSchedulerCompletion(RunQueueSchedulerSpeed):
    """
    A scheduler optimised to complete .bb files are quickly as possible. The 
    priority map is sorted by task weight, but then reordered so once a given 
    .bb file starts to build, its completed as quickly as possible. This works
    well where disk space is at a premium and classes like OE's rm_work are in 
    force.
    """
    def __init__(self, runqueue):
        RunQueueSchedulerSpeed.__init__(self, runqueue)
        from copy import deepcopy

        #FIXME - whilst this groups all fnids together it does not reorder the
        #fnid groups optimally.
 
        basemap = deepcopy(self.prio_map)
        self.prio_map = []
        while (len(basemap) > 0):
            entry = basemap.pop(0)
            self.prio_map.append(entry)
            fnid = self.rq.runq_fnid[entry]
            todel = []
            for entry in basemap:
                entry_fnid = self.rq.runq_fnid[entry]
                if entry_fnid == fnid:
                    todel.append(basemap.index(entry))
                    self.prio_map.append(entry)
            todel.reverse()
            for idx in todel:
                del basemap[idx]

class RunQueue:
    """
    BitBake Run Queue implementation
    """
    def __init__(self, cooker, cfgData, dataCache, taskData, targets):
        self.reset_runqueue()
        self.cooker = cooker
        self.dataCache = dataCache
        self.taskData = taskData
        self.cfgData = cfgData
        self.targets = targets

        self.number_tasks = int(bb.data.getVar("BB_NUMBER_THREADS", cfgData, 1) or 1)
        self.multi_provider_whitelist = (bb.data.getVar("MULTI_PROVIDER_WHITELIST", cfgData, 1) or "").split()
        self.scheduler = bb.data.getVar("BB_SCHEDULER", cfgData, 1) or "speed"
        self.stamppolicy = bb.data.getVar("BB_STAMP_POLICY", cfgData, 1) or "perfile"
        self.stampwhitelist = bb.data.getVar("BB_STAMP_WHITELIST", cfgData, 1) or ""

    def reset_runqueue(self):
        self.runq_fnid = []
        self.runq_task = []
        self.runq_depends = []
        self.runq_revdeps = []
        self.state = runQueuePrepare

    def runq_depends_names(self, ids):
        import re
        ret = []
        for id in self.runq_depends[ids]:
            nam = os.path.basename(self.get_user_idstring(id))
            nam = re.sub("_[^,]*,", ",", nam)
            ret.extend([nam])
        return ret

    def get_user_idstring(self, task):
        fn = self.taskData.fn_index[self.runq_fnid[task]]
        taskname = self.runq_task[task]
        return "%s, %s" % (fn, taskname)

    def get_task_id(self, fnid, taskname):
        for listid in range(len(self.runq_fnid)):
            if self.runq_fnid[listid] == fnid and self.runq_task[listid] == taskname:
                return listid
        return None

    def circular_depchains_handler(self, tasks):
        """
        Some tasks aren't buildable, likely due to circular dependency issues.
        Identify the circular dependencies and print them in a user readable format.
        """
        from copy import deepcopy

        valid_chains = []
        explored_deps = {}
        msgs = []

        def chain_reorder(chain):
            """
            Reorder a dependency chain so the lowest task id is first
            """
            lowest = 0
            new_chain = []
            for entry in range(len(chain)):
                if chain[entry] < chain[lowest]:
                    lowest = entry
            new_chain.extend(chain[lowest:])
            new_chain.extend(chain[:lowest])
            return new_chain

        def chain_compare_equal(chain1, chain2):
            """
            Compare two dependency chains and see if they're the same
            """
            if len(chain1) != len(chain2):
                return False
            for index in range(len(chain1)):
                if chain1[index] != chain2[index]:
                    return False
            return True
            
        def chain_array_contains(chain, chain_array):
            """
            Return True if chain_array contains chain
            """
            for ch in chain_array:
                if chain_compare_equal(ch, chain):
                    return True
            return False

        def find_chains(taskid, prev_chain):
            prev_chain.append(taskid)
            total_deps = []
            total_deps.extend(self.runq_revdeps[taskid])
            for revdep in self.runq_revdeps[taskid]:
                if revdep in prev_chain:
                    idx = prev_chain.index(revdep)
                    # To prevent duplicates, reorder the chain to start with the lowest taskid
                    # and search through an array of those we've already printed
                    chain = prev_chain[idx:]
                    new_chain = chain_reorder(chain)
                    if not chain_array_contains(new_chain, valid_chains):
                        valid_chains.append(new_chain)
                        msgs.append("Dependency loop #%d found:\n" % len(valid_chains))
                        for dep in new_chain:
                            msgs.append("  Task %s (%s) (dependent Tasks %s)\n" % (dep, self.get_user_idstring(dep), self.runq_depends_names(dep)))
                        msgs.append("\n")
                    if len(valid_chains) > 10:
                        msgs.append("Aborted dependency loops search after 10 matches.\n")
                        return msgs
                    continue
                scan = False
                if revdep not in explored_deps:
                    scan = True
                elif revdep in explored_deps[revdep]:
                    scan = True
                else:
                    for dep in prev_chain:
                        if dep in explored_deps[revdep]:
                            scan = True
                if scan:
                    find_chains(revdep, deepcopy(prev_chain))
                for dep in explored_deps[revdep]:
                    if dep not in total_deps:
                        total_deps.append(dep)

            explored_deps[taskid] = total_deps

        for task in tasks:
            find_chains(task, [])

        return msgs

    def calculate_task_weights(self, endpoints):
        """
        Calculate a number representing the "weight" of each task. Heavier weighted tasks 
        have more dependencies and hence should be executed sooner for maximum speed.

        This function also sanity checks the task list finding tasks that its not
        possible to execute due to circular dependencies.
        """

        numTasks = len(self.runq_fnid)
        weight = []
        deps_left = []
        task_done = []

        for listid in range(numTasks):
            task_done.append(False)
            weight.append(0)
            deps_left.append(len(self.runq_revdeps[listid]))

        for listid in endpoints:
            weight[listid] = 1
            task_done[listid] = True

        while 1:
            next_points = []
            for listid in endpoints:
                for revdep in self.runq_depends[listid]:
                    weight[revdep] = weight[revdep] + weight[listid]
                    deps_left[revdep] = deps_left[revdep] - 1
                    if deps_left[revdep] == 0:
                        next_points.append(revdep)
                        task_done[revdep] = True
            endpoints = next_points
            if len(next_points) == 0:
                break      

        # Circular dependency sanity check
        problem_tasks = []
        for task in range(numTasks):
            if task_done[task] is False or deps_left[task] != 0:
                problem_tasks.append(task)
                bb.msg.debug(2, bb.msg.domain.RunQueue, "Task %s (%s) is not buildable\n" % (task, self.get_user_idstring(task)))
                bb.msg.debug(2, bb.msg.domain.RunQueue, "(Complete marker was %s and the remaining dependency count was %s)\n\n" % (task_done[task], deps_left[task]))

        if problem_tasks:
            message = "Unbuildable tasks were found.\n"
            message = message + "These are usually caused by circular dependencies and any circular dependency chains found will be printed below. Increase the debug level to see a list of unbuildable tasks.\n\n"
            message = message + "Identifying dependency loops (this may take a short while)...\n"
            bb.msg.error(bb.msg.domain.RunQueue, message)

            msgs = self.circular_depchains_handler(problem_tasks)

            message = "\n"
            for msg in msgs:
                message = message + msg
            bb.msg.fatal(bb.msg.domain.RunQueue, message)

        return weight

    def prepare_runqueue(self):
        """
        Turn a set of taskData into a RunQueue and compute data needed 
        to optimise the execution order.
        """

        runq_build = []
        recursive_tdepends = {}
        runq_recrdepends = []
        tdepends_fnid = {}

        taskData = self.taskData

        if len(taskData.tasks_name) == 0:
            # Nothing to do
            return

        bb.msg.note(1, bb.msg.domain.RunQueue, "Preparing runqueue")

        # Step A - Work out a list of tasks to run
        #
        # Taskdata gives us a list of possible providers for every build and run
        # target ordered by priority. It also gives information on each of those 
        # providers.
        #
        # To create the actual list of tasks to execute we fix the list of 
        # providers and then resolve the dependencies into task IDs. This 
        # process is repeated for each type of dependency (tdepends, deptask, 
        # rdeptast, recrdeptask, idepends).

        def add_build_dependencies(depids, tasknames, depends):
            for depid in depids:
                # Won't be in build_targets if ASSUME_PROVIDED
                if depid not in taskData.build_targets:
                    continue
                depdata = taskData.build_targets[depid][0]
                if depdata is None:
                    continue
                dep = taskData.fn_index[depdata]
                for taskname in tasknames:
                    taskid = taskData.gettask_id(dep, taskname, False)
                    if taskid is not None:
                        depends.append(taskid)

        def add_runtime_dependencies(depids, tasknames, depends):
            for depid in depids:
                if depid not in taskData.run_targets:
                    continue
                depdata = taskData.run_targets[depid][0]
                if depdata is None:
                    continue
                dep = taskData.fn_index[depdata]
                for taskname in tasknames:
                    taskid = taskData.gettask_id(dep, taskname, False)
                    if taskid is not None:
                        depends.append(taskid)

        for task in range(len(taskData.tasks_name)):
            depends = []
            recrdepends = []
            fnid = taskData.tasks_fnid[task]
            fn = taskData.fn_index[fnid]
            task_deps = self.dataCache.task_deps[fn]

            bb.msg.debug(2, bb.msg.domain.RunQueue, "Processing %s:%s" %(fn, taskData.tasks_name[task]))

            if fnid not in taskData.failed_fnids:

                # Resolve task internal dependencies 
                #
                # e.g. addtask before X after Y
                depends = taskData.tasks_tdepends[task]

                # Resolve 'deptask' dependencies 
                #
                # e.g. do_sometask[deptask] = "do_someothertask"
                # (makes sure sometask runs after someothertask of all DEPENDS)
                if 'deptask' in task_deps and taskData.tasks_name[task] in task_deps['deptask']:
                    tasknames = task_deps['deptask'][taskData.tasks_name[task]].split()
                    add_build_dependencies(taskData.depids[fnid], tasknames, depends)

                # Resolve 'rdeptask' dependencies 
                #
                # e.g. do_sometask[rdeptask] = "do_someothertask"
                # (makes sure sometask runs after someothertask of all RDEPENDS)
                if 'rdeptask' in task_deps and taskData.tasks_name[task] in task_deps['rdeptask']:
                    taskname = task_deps['rdeptask'][taskData.tasks_name[task]]
                    add_runtime_dependencies(taskData.rdepids[fnid], [taskname], depends)

                # Resolve inter-task dependencies 
                #
                # e.g. do_sometask[depends] = "targetname:do_someothertask"
                # (makes sure sometask runs after targetname's someothertask)
                if fnid not in tdepends_fnid:
                    tdepends_fnid[fnid] = set()
                idepends = taskData.tasks_idepends[task]
                for (depid, idependtask) in idepends:
                    if depid in taskData.build_targets:
                        # Won't be in build_targets if ASSUME_PROVIDED
                        depdata = taskData.build_targets[depid][0]
                        if depdata is not None:
                            dep = taskData.fn_index[depdata]
                            taskid = taskData.gettask_id(dep, idependtask)
                            depends.append(taskid)
                            if depdata != fnid:
                                tdepends_fnid[fnid].add(taskid)


                # Resolve recursive 'recrdeptask' dependencies (A)
                #
                # e.g. do_sometask[recrdeptask] = "do_someothertask"
                # (makes sure sometask runs after someothertask of all DEPENDS, RDEPENDS and intertask dependencies, recursively)
                # We cover the recursive part of the dependencies below
                if 'recrdeptask' in task_deps and taskData.tasks_name[task] in task_deps['recrdeptask']:
                    for taskname in task_deps['recrdeptask'][taskData.tasks_name[task]].split():
                        recrdepends.append(taskname)
                        add_build_dependencies(taskData.depids[fnid], [taskname], depends)
                        add_runtime_dependencies(taskData.rdepids[fnid], [taskname], depends)

                # Rmove all self references
                if task in depends:
                    newdep = []
                    bb.msg.debug(2, bb.msg.domain.RunQueue, "Task %s (%s %s) contains self reference! %s" % (task, taskData.fn_index[taskData.tasks_fnid[task]], taskData.tasks_name[task], depends))
                    for dep in depends:
                       if task != dep:
                          newdep.append(dep)
                    depends = newdep

            self.runq_fnid.append(taskData.tasks_fnid[task])
            self.runq_task.append(taskData.tasks_name[task])
            self.runq_depends.append(set(depends))
            self.runq_revdeps.append(set())

            runq_build.append(0)
            runq_recrdepends.append(recrdepends)

        #
        # Build a list of recursive cumulative dependencies for each fnid
        # We do this by fnid, since if A depends on some task in B
        # we're interested in later tasks B's fnid might have but B itself 
        # doesn't depend on
        #
        # Algorithm is O(tasks) + O(tasks)*O(fnids)
        #
        reccumdepends = {}
        for task in range(len(self.runq_fnid)):
            fnid = self.runq_fnid[task]
            if fnid not in reccumdepends:
                if fnid in tdepends_fnid:
                    reccumdepends[fnid] = tdepends_fnid[fnid]
                else:
                    reccumdepends[fnid] = set()
            reccumdepends[fnid].update(self.runq_depends[task])
        for task in range(len(self.runq_fnid)):
            taskfnid = self.runq_fnid[task]
            for fnid in reccumdepends:
                if task in reccumdepends[fnid]:
                    reccumdepends[fnid].add(task)
                    if taskfnid in reccumdepends:
                        reccumdepends[fnid].update(reccumdepends[taskfnid])


        # Resolve recursive 'recrdeptask' dependencies (B)
        #
        # e.g. do_sometask[recrdeptask] = "do_someothertask"
        # (makes sure sometask runs after someothertask of all DEPENDS, RDEPENDS and intertask dependencies, recursively)
        for task in range(len(self.runq_fnid)):
            if len(runq_recrdepends[task]) > 0:
                taskfnid = self.runq_fnid[task]
                for dep in reccumdepends[taskfnid]:
                    # Ignore self references 
                    if dep == task:
                        continue
                    for taskname in runq_recrdepends[task]:
                        if taskData.tasks_name[dep] == taskname:
                            self.runq_depends[task].add(dep)

        # Step B - Mark all active tasks
        #
        # Start with the tasks we were asked to run and mark all dependencies
        # as active too. If the task is to be 'forced', clear its stamp. Once
        # all active tasks are marked, prune the ones we don't need.

        bb.msg.note(2, bb.msg.domain.RunQueue, "Marking Active Tasks")

        def mark_active(listid, depth):
            """
            Mark an item as active along with its depends
            (calls itself recursively)
            """

            if runq_build[listid] == 1:
                return

            runq_build[listid] = 1

            depends = self.runq_depends[listid]
            for depend in depends:
                mark_active(depend, depth+1)

        self.target_pairs = []
        for target in self.targets:
            targetid = taskData.getbuild_id(target[0])

            if targetid not in taskData.build_targets:
                continue

            if targetid in taskData.failed_deps:
                continue

            fnid = taskData.build_targets[targetid][0]
            fn = taskData.fn_index[fnid]
            self.target_pairs.append((fn, target[1]))

            # Remove stamps for targets if force mode active
            if self.cooker.configuration.force:
                bb.msg.note(2, bb.msg.domain.RunQueue, "Remove stamp %s, %s" % (target[1], fn))
                bb.build.del_stamp(target[1], self.dataCache, fn)

            if fnid in taskData.failed_fnids:
                continue

            if target[1] not in taskData.tasks_lookup[fnid]:
                bb.msg.fatal(bb.msg.domain.RunQueue, "Task %s does not exist for target %s" % (target[1], target[0]))

            listid = taskData.tasks_lookup[fnid][target[1]]

            mark_active(listid, 1)

        # Step C - Prune all inactive tasks
        #
        # Once all active tasks are marked, prune the ones we don't need.

        maps = []
        delcount = 0
        for listid in range(len(self.runq_fnid)):
            if runq_build[listid-delcount] == 1:
                maps.append(listid-delcount)
            else:
                del self.runq_fnid[listid-delcount]
                del self.runq_task[listid-delcount]
                del self.runq_depends[listid-delcount]
                del runq_build[listid-delcount]
                del self.runq_revdeps[listid-delcount]
                delcount = delcount + 1
                maps.append(-1)

        #
        # Step D - Sanity checks and computation
        #

        # Check to make sure we still have tasks to run
        if len(self.runq_fnid) == 0:
            if not taskData.abort:
                bb.msg.fatal(bb.msg.domain.RunQueue, "All buildable tasks have been run but the build is incomplete (--continue mode). Errors for the tasks that failed will have been printed above.")
            else:
                bb.msg.fatal(bb.msg.domain.RunQueue, "No active tasks and not in --continue mode?! Please report this bug.")

        bb.msg.note(2, bb.msg.domain.RunQueue, "Pruned %s inactive tasks, %s left" % (delcount, len(self.runq_fnid)))

        # Remap the dependencies to account for the deleted tasks
        # Check we didn't delete a task we depend on
        for listid in range(len(self.runq_fnid)):
            newdeps = []
            origdeps = self.runq_depends[listid]
            for origdep in origdeps:
                if maps[origdep] == -1:
                    bb.msg.fatal(bb.msg.domain.RunQueue, "Invalid mapping - Should never happen!")
                newdeps.append(maps[origdep])
            self.runq_depends[listid] = set(newdeps)

        bb.msg.note(2, bb.msg.domain.RunQueue, "Assign Weightings")

        # Generate a list of reverse dependencies to ease future calculations
        for listid in range(len(self.runq_fnid)):
            for dep in self.runq_depends[listid]:
                self.runq_revdeps[dep].add(listid)

        # Identify tasks at the end of dependency chains
        # Error on circular dependency loops (length two)
        endpoints = []
        for listid in range(len(self.runq_fnid)):
            revdeps = self.runq_revdeps[listid]
            if len(revdeps) == 0:
                endpoints.append(listid)
            for dep in revdeps:
                if dep in self.runq_depends[listid]:
                    #self.dump_data(taskData)
                    bb.msg.fatal(bb.msg.domain.RunQueue, "Task %s (%s) has circular dependency on %s (%s)" % (taskData.fn_index[self.runq_fnid[dep]], self.runq_task[dep] , taskData.fn_index[self.runq_fnid[listid]], self.runq_task[listid]))

        bb.msg.note(2, bb.msg.domain.RunQueue, "Compute totals (have %s endpoint(s))" % len(endpoints))

        # Calculate task weights 
        # Check of higher length circular dependencies
        self.runq_weight = self.calculate_task_weights(endpoints)

        # Decide what order to execute the tasks in, pick a scheduler
        #self.sched = RunQueueScheduler(self)
        if self.scheduler == "completion":
            self.sched = RunQueueSchedulerCompletion(self)
        else:
            self.sched = RunQueueSchedulerSpeed(self)

        # Sanity Check - Check for multiple tasks building the same provider
        prov_list = {}
        seen_fn = []
        for task in range(len(self.runq_fnid)):
            fn = taskData.fn_index[self.runq_fnid[task]]
            if fn in seen_fn:
                continue
            seen_fn.append(fn)
            for prov in self.dataCache.fn_provides[fn]:
                if prov not in prov_list:
                    prov_list[prov] = [fn]
                elif fn not in prov_list[prov]: 
                    prov_list[prov].append(fn)
        error = False
        for prov in prov_list:
            if len(prov_list[prov]) > 1 and prov not in self.multi_provider_whitelist:
                error = True
                bb.msg.error(bb.msg.domain.RunQueue, "Multiple .bb files are due to be built which each provide %s (%s).\n This usually means one provides something the other doesn't and should." % (prov, " ".join(prov_list[prov])))
        #if error:
        #    bb.msg.fatal(bb.msg.domain.RunQueue, "Corrupted metadata configuration detected, aborting...")


        # Create a whitelist usable by the stamp checks
        stampfnwhitelist = []
        for entry in self.stampwhitelist.split():
            entryid = self.taskData.getbuild_id(entry)
            if entryid not in self.taskData.build_targets:
                continue
            fnid = self.taskData.build_targets[entryid][0]
            fn = self.taskData.fn_index[fnid]
            stampfnwhitelist.append(fn)
        self.stampfnwhitelist = stampfnwhitelist

        #self.dump_data(taskData)

        self.state = runQueueRunInit

    def check_stamps(self):
        unchecked = {}
        current = []
        notcurrent = []
        buildable = []

        if self.stamppolicy == "perfile":
            fulldeptree = False
        else:
            fulldeptree = True
            stampwhitelist = []
            if self.stamppolicy == "whitelist":
                stampwhitelist = self.self.stampfnwhitelist

        for task in range(len(self.runq_fnid)):
            unchecked[task] = ""
            if len(self.runq_depends[task]) == 0:
                buildable.append(task)

        def check_buildable(self, task, buildable):
             for revdep in self.runq_revdeps[task]:
                alldeps = 1
                for dep in self.runq_depends[revdep]:
                    if dep in unchecked:
                        alldeps = 0
                if alldeps == 1:
                    if revdep in unchecked:
                        buildable.append(revdep)

        for task in range(len(self.runq_fnid)):
            if task not in unchecked:
                continue
            fn = self.taskData.fn_index[self.runq_fnid[task]]
            taskname = self.runq_task[task]
            stampfile = "%s.%s" % (self.dataCache.stamp[fn], taskname)
            # If the stamp is missing its not current
            if not os.access(stampfile, os.F_OK):
                del unchecked[task]
                notcurrent.append(task)
                check_buildable(self, task, buildable)
                continue
            # If its a 'nostamp' task, it's not current
            taskdep = self.dataCache.task_deps[fn]
            if 'nostamp' in taskdep and task in taskdep['nostamp']:
                del unchecked[task]
                notcurrent.append(task)
                check_buildable(self, task, buildable)
                continue

        while (len(buildable) > 0):
            nextbuildable = []
            for task in buildable:
                if task in unchecked:
                    fn = self.taskData.fn_index[self.runq_fnid[task]]
                    taskname = self.runq_task[task]
                    stampfile = "%s.%s" % (self.dataCache.stamp[fn], taskname)
                    iscurrent = True

                    t1 = os.stat(stampfile)[stat.ST_MTIME]
                    for dep in self.runq_depends[task]:
                        if iscurrent:
                            fn2 = self.taskData.fn_index[self.runq_fnid[dep]]
                            taskname2 = self.runq_task[dep]
                            stampfile2 = "%s.%s" % (self.dataCache.stamp[fn2], taskname2)
                            if fn == fn2 or (fulldeptree and fn2 not in stampwhitelist):
                                if dep in notcurrent:
                                    iscurrent = False
                                else:
                                    t2 = os.stat(stampfile2)[stat.ST_MTIME]
                                    if t1 < t2:
                                        iscurrent = False
                    del unchecked[task]
                    if iscurrent:
                        current.append(task)
                    else:
                        notcurrent.append(task)

                check_buildable(self, task, nextbuildable)

            buildable = nextbuildable

        #for task in range(len(self.runq_fnid)):
        #    fn = self.taskData.fn_index[self.runq_fnid[task]]
        #    taskname = self.runq_task[task]
        #    print "%s %s.%s" % (task, taskname, fn)

        #print "Unchecked: %s" % unchecked
        #print "Current: %s" % current
        #print "Not current: %s" % notcurrent

        if len(unchecked) > 0:
            bb.fatal("check_stamps fatal internal error")
        return current

    def check_stamp_task(self, task):

        if self.stamppolicy == "perfile":
            fulldeptree = False
        else:
            fulldeptree = True
            stampwhitelist = []
            if self.stamppolicy == "whitelist":
                stampwhitelist = self.stampfnwhitelist

        fn = self.taskData.fn_index[self.runq_fnid[task]]
        taskname = self.runq_task[task]
        stampfile = "%s.%s" % (self.dataCache.stamp[fn], taskname)
        # If the stamp is missing its not current
        if not os.access(stampfile, os.F_OK):
            bb.msg.debug(2, bb.msg.domain.RunQueue, "Stampfile %s not available\n" % stampfile)
            return False
        # If its a 'nostamp' task, it's not current
        taskdep = self.dataCache.task_deps[fn]
        if 'nostamp' in taskdep and taskname in taskdep['nostamp']:
            bb.msg.debug(2, bb.msg.domain.RunQueue, "%s.%s is nostamp\n" % (fn, taskname))
            return False

        iscurrent = True
        t1 =  os.stat(stampfile)[stat.ST_MTIME]
        for dep in self.runq_depends[task]:
            if iscurrent:
                fn2 = self.taskData.fn_index[self.runq_fnid[dep]]
                taskname2 = self.runq_task[dep]
                stampfile2 = "%s.%s" % (self.dataCache.stamp[fn2], taskname2)
                if fn == fn2 or (fulldeptree and fn2 not in stampwhitelist):
                    try:
                        t2 = os.stat(stampfile2)[stat.ST_MTIME]
                        if t1 < t2:
                            bb.msg.debug(2, bb.msg.domain.RunQueue, "Stampfile %s < %s" % (stampfile,stampfile2))
                            iscurrent = False
                    except:
                        bb.msg.debug(2, bb.msg.domain.RunQueue, "Exception reading %s for %s" % (stampfile2 ,stampfile))
                        iscurrent = False

        return iscurrent

    def execute_runqueue(self):
        """
        Run the tasks in a queue prepared by prepare_runqueue
        Upon failure, optionally try to recover the build using any alternate providers
        (if the abort on failure configuration option isn't set)
        """

        if self.state is runQueuePrepare:
            self.prepare_runqueue()

        if self.state is runQueueRunInit:
            bb.msg.note(1, bb.msg.domain.RunQueue, "Executing runqueue")
            self.execute_runqueue_initVars()

        if self.state is runQueueRunning:
            self.execute_runqueue_internal()

        if self.state is runQueueCleanUp:
            self.finish_runqueue()

        if self.state is runQueueFailed:
            if not self.taskData.tryaltconfigs:
                raise bb.runqueue.TaskFailure(self.failed_fnids)
            for fnid in self.failed_fnids:
                self.taskData.fail_fnid(fnid)
            self.reset_runqueue()

        if self.state is runQueueComplete:
            # All done
            bb.msg.note(1, bb.msg.domain.RunQueue, "Tasks Summary: Attempted %d tasks of which %d didn't need to be rerun and %d failed." % (self.stats.completed, self.stats.skipped, self.stats.failed))
            return False

        if self.state is runQueueChildProcess:
            print "Child process"
            return False

        # Loop
        return True

    def execute_runqueue_initVars(self):

        self.stats = RunQueueStats(len(self.runq_fnid))

        self.runq_buildable = []
        self.runq_running = []
        self.runq_complete = []
        self.build_pids = {}
        self.build_pipes = {}
        self.failed_fnids = []

        # Mark initial buildable tasks
        for task in range(self.stats.total):
            self.runq_running.append(0)
            self.runq_complete.append(0)
            if len(self.runq_depends[task]) == 0:
                self.runq_buildable.append(1)
            else:
                self.runq_buildable.append(0)

        self.state = runQueueRunning

        event.fire(bb.event.StampUpdate(self.target_pairs, self.dataCache.stamp), self.cfgData)

    def task_complete(self, task):
        """
        Mark a task as completed
        Look at the reverse dependencies and mark any task with 
        completed dependencies as buildable
        """
        self.runq_complete[task] = 1
        for revdep in self.runq_revdeps[task]:
            if self.runq_running[revdep] == 1:
                continue
            if self.runq_buildable[revdep] == 1:
                continue
            alldeps = 1
            for dep in self.runq_depends[revdep]:
                if self.runq_complete[dep] != 1:
                    alldeps = 0
            if alldeps == 1:
                self.runq_buildable[revdep] = 1
                fn = self.taskData.fn_index[self.runq_fnid[revdep]]
                taskname = self.runq_task[revdep]
                bb.msg.debug(1, bb.msg.domain.RunQueue, "Marking task %s (%s, %s) as buildable" % (revdep, fn, taskname))

    def task_fail(self, task, exitcode):
        """
        Called when a task has failed
        Updates the state engine with the failure
        """
        bb.msg.error(bb.msg.domain.RunQueue, "Task %s (%s) failed with %s" % (task, self.get_user_idstring(task), exitcode))
        self.stats.taskFailed()
        fnid = self.runq_fnid[task]
        self.failed_fnids.append(fnid)
        bb.event.fire(runQueueTaskFailed(task, self.stats, self), self.cfgData)
        if self.taskData.abort:
            self.state = runQueueCleanUp

    def execute_runqueue_internal(self):
        """
        Run the tasks in a queue prepared by prepare_runqueue
        """

        if self.stats.total == 0:
            # nothing to do
            self.state = runQueueCleanUp

        while True:
            task = None
            if self.stats.active < self.number_tasks:
                task = self.sched.next()
            if task is not None:
                fn = self.taskData.fn_index[self.runq_fnid[task]]

                taskname = self.runq_task[task]
                if self.check_stamp_task(task):
                    bb.msg.debug(2, bb.msg.domain.RunQueue, "Stamp current task %s (%s)" % (task, self.get_user_idstring(task)))
                    self.runq_running[task] = 1
                    self.runq_buildable[task] = 1
                    self.task_complete(task)
                    self.stats.taskCompleted()
                    self.stats.taskSkipped()
                    continue

                sys.stdout.flush()
                sys.stderr.flush()
                try:
                    pipein, pipeout = os.pipe()
                    pid = os.fork() 
                except OSError, e: 
                    bb.msg.fatal(bb.msg.domain.RunQueue, "fork failed: %d (%s)" % (e.errno, e.strerror))
                if pid == 0:
                    os.close(pipein)
                    # Save out the PID so that the event can include it the
                    # events
                    bb.event.worker_pid = os.getpid()
                    bb.event.worker_pipe = pipeout

                    self.state = runQueueChildProcess
                    # Make the child the process group leader
                    os.setpgid(0, 0)
                    # No stdin
                    newsi = os.open('/dev/null', os.O_RDWR)
                    os.dup2(newsi, sys.stdin.fileno())
                    # Stdout to a logfile
                    #logout = data.expand("${TMPDIR}/log/stdout.%s" % os.getpid(), self.cfgData, True)
                    #mkdirhier(os.path.dirname(logout))
                    #newso = open(logout, 'w')
                    #os.dup2(newso.fileno(), sys.stdout.fileno())
                    #os.dup2(newso.fileno(), sys.stderr.fileno())

                    bb.event.fire(runQueueTaskStarted(task, self.stats, self), self.cfgData)
                    bb.msg.note(1, bb.msg.domain.RunQueue,
                                "Running task %d of %d (ID: %s, %s)" % (self.stats.completed + self.stats.active + 1,
                                                                        self.stats.total,
                                                                        task,
                                                                        self.get_user_idstring(task)))

                    bb.data.setVar("__RUNQUEUE_DO_NOT_USE_EXTERNALLY", self, self.cooker.configuration.data)
                    bb.data.setVar("__RUNQUEUE_DO_NOT_USE_EXTERNALLY2", fn, self.cooker.configuration.data)
                    try:
                        self.cooker.tryBuild(fn, taskname[3:])
                    except bb.build.EventException:
                        bb.msg.error(bb.msg.domain.Build, "Build of " + fn + " " + taskname + " failed")
                        os._exit(1)
                    except:
                        bb.msg.error(bb.msg.domain.Build, "Build of " + fn + " " + taskname + " failed")
                        os._exit(1)
                    os._exit(0)

                self.build_pids[pid] = task
                self.build_pipes[pid] = runQueuePipe(pipein, pipeout, self.cfgData)
                self.runq_running[task] = 1
                self.stats.taskActive()
                if self.stats.active < self.number_tasks:
                    continue

            for pipe in self.build_pipes:
                self.build_pipes[pipe].read()

            if self.stats.active > 0:
                result = os.waitpid(-1, os.WNOHANG)
                if result[0] is 0 and result[1] is 0:
                    return
                task = self.build_pids[result[0]]
                del self.build_pids[result[0]]
                self.build_pipes[result[0]].close()
                del self.build_pipes[result[0]]
                if result[1] != 0:
                    self.task_fail(task, result[1])
                    return
                self.task_complete(task)
                self.stats.taskCompleted()
                bb.event.fire(runQueueTaskCompleted(task, self.stats, self), self.cfgData)
                continue

            if len(self.failed_fnids) != 0:
                self.state = runQueueFailed
                return

            # Sanity Checks
            for task in range(self.stats.total):
                if self.runq_buildable[task] == 0:
                    bb.msg.error(bb.msg.domain.RunQueue, "Task %s never buildable!" % task)
                if self.runq_running[task] == 0:
                    bb.msg.error(bb.msg.domain.RunQueue, "Task %s never ran!" % task)
                if self.runq_complete[task] == 0:
                    bb.msg.error(bb.msg.domain.RunQueue, "Task %s never completed!" % task)
            self.state = runQueueComplete
            return

    def finish_runqueue_now(self):
        bb.msg.note(1, bb.msg.domain.RunQueue, "Sending SIGINT to remaining %s tasks" % self.stats.active)
        for k, v in self.build_pids.iteritems():
             try:
                 os.kill(-k, signal.SIGINT)
             except:
                 pass
        for pipe in self.build_pipes:
            self.build_pipes[pipe].read()

    def finish_runqueue(self, now = False):
        self.state = runQueueCleanUp

        for pipe in self.build_pipes:
            self.build_pipes[pipe].read()

        if now:
            self.finish_runqueue_now()
        try:
            while self.stats.active > 0:
                bb.event.fire(runQueueExitWait(self.stats.active), self.cfgData)
                #bb.msg.note(1, bb.msg.domain.RunQueue, "Waiting for %s active tasks to finish" % self.stats.active)
                #tasknum = 1
                #for k, v in self.build_pids.iteritems():
                #    bb.msg.note(1, bb.msg.domain.RunQueue, "%s: %s (pid %s)" % (tasknum, self.get_user_idstring(v), k))
                #    tasknum = tasknum + 1
                result = os.waitpid(-1, os.WNOHANG)
                if result[0] is 0 and result[1] is 0:
                    return
                task = self.build_pids[result[0]]
                del self.build_pids[result[0]]
                self.build_pipes[result[0]].close()
                del self.build_pipes[result[0]]
                if result[1] != 0:
                    self.task_fail(task, result[1])
                else:
                    self.stats.taskCompleted()
                    bb.event.fire(runQueueTaskCompleted(task, self.stats, self), self.cfgData)
        except:
            self.finish_runqueue_now()
            raise

        if len(self.failed_fnids) != 0:
            self.state = runQueueFailed
            return

        self.state = runQueueComplete
        return

    def dump_data(self, taskQueue):
        """
        Dump some debug information on the internal data structures
        """
        bb.msg.debug(3, bb.msg.domain.RunQueue, "run_tasks:")
        for task in range(len(self.runq_task)):
                bb.msg.debug(3, bb.msg.domain.RunQueue, " (%s)%s - %s: %s   Deps %s RevDeps %s" % (task, 
                        taskQueue.fn_index[self.runq_fnid[task]], 
                        self.runq_task[task], 
                        self.runq_weight[task], 
                        self.runq_depends[task], 
                        self.runq_revdeps[task]))

        bb.msg.debug(3, bb.msg.domain.RunQueue, "sorted_tasks:")
        for task1 in range(len(self.runq_task)):
            if task1 in self.prio_map:
                task = self.prio_map[task1]
                bb.msg.debug(3, bb.msg.domain.RunQueue, " (%s)%s - %s: %s   Deps %s RevDeps %s" % (task, 
                        taskQueue.fn_index[self.runq_fnid[task]], 
                        self.runq_task[task], 
                        self.runq_weight[task], 
                        self.runq_depends[task], 
                        self.runq_revdeps[task]))


class TaskFailure(Exception):
    """
    Exception raised when a task in a runqueue fails
    """
    def __init__(self, x): 
        self.args = x


class runQueueExitWait(bb.event.Event):
    """
    Event when waiting for task processes to exit
    """

    def __init__(self, remain):
        self.remain = remain
        self.message = "Waiting for %s active tasks to finish" % remain
        bb.event.Event.__init__(self)

class runQueueEvent(bb.event.Event):
    """
    Base runQueue event class
    """
    def __init__(self, task, stats, rq):
        self.taskid = task
        self.taskstring = rq.get_user_idstring(task)
        self.stats = stats
        bb.event.Event.__init__(self)

class runQueueTaskStarted(runQueueEvent):
    """
    Event notifing a task was started
    """
    def __init__(self, task, stats, rq):
        runQueueEvent.__init__(self, task, stats, rq)
        self.message = "Running task %s (%d of %d) (%s)" % (task, stats.completed + stats.active + 1, self.stats.total, self.taskstring)

class runQueueTaskFailed(runQueueEvent):
    """
    Event notifing a task failed
    """
    def __init__(self, task, stats, rq):
        runQueueEvent.__init__(self, task, stats, rq)
        self.message = "Task %s failed (%s)" % (task, self.taskstring)

class runQueueTaskCompleted(runQueueEvent):
    """
    Event notifing a task completed
    """
    def __init__(self, task, stats, rq):
        runQueueEvent.__init__(self, task, stats, rq)
        self.message = "Task %s completed (%s)" % (task, self.taskstring)

def check_stamp_fn(fn, taskname, d):
    rq = bb.data.getVar("__RUNQUEUE_DO_NOT_USE_EXTERNALLY", d)
    fn = bb.data.getVar("__RUNQUEUE_DO_NOT_USE_EXTERNALLY2", d)
    fnid = rq.taskData.getfn_id(fn)
    taskid = rq.get_task_id(fnid, taskname)
    if taskid is not None:
        return rq.check_stamp_task(taskid)
    return None

class runQueuePipe():
    """
    Abstraction for a pipe between a worker thread and the server
    """
    def __init__(self, pipein, pipeout, d):
        self.fd = pipein
        os.close(pipeout)
        fcntl.fcntl(self.fd, fcntl.F_SETFL, fcntl.fcntl(self.fd, fcntl.F_GETFL) | os.O_NONBLOCK)
        self.queue = ""
        self.d = d

    def read(self):
        start = len(self.queue)
        try:
            self.queue = self.queue + os.read(self.fd, 1024)
        except OSError:
            pass
        end = len(self.queue)
        index = self.queue.find("</event>")
        while index != -1:
            bb.event.fire_from_worker(self.queue[:index+8], self.d)
            self.queue = self.queue[index+8:]
            index = self.queue.find("</event>")
        return (end > start)

    def close(self):
        while self.read():
            continue
        if len(self.queue) > 0:
            print "Warning, worker left partial message"
        os.close(self.fd)