summaryrefslogtreecommitdiffstats
path: root/Modules/ExternalProject.cmake
blob: d6a6b7275a118f7de24da5cf31da6b5e4d144393 (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
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
#.rst:
# ExternalProject
# ---------------
#
# Create custom targets to build projects in external trees
#
# The ``ExternalProject_Add`` function creates a custom target to drive
# download, update/patch, configure, build, install and test steps of an
# external project:
#
# .. code-block:: cmake
#
#  ExternalProject_Add(<name>    # Name for custom target
#    [DEPENDS projects...]       # Targets on which the project depends
#    [PREFIX dir]                # Root dir for entire project
#    [LIST_SEPARATOR sep]        # Sep to be replaced by ; in cmd lines
#    [TMP_DIR dir]               # Directory to store temporary files
#    [STAMP_DIR dir]             # Directory to store step timestamps
#    [EXCLUDE_FROM_ALL 1]        # The "all" target does not depend on this
#   #--Download step--------------
#    [DOWNLOAD_NAME fname]       # File name to store (if not end of URL)
#    [DOWNLOAD_DIR dir]          # Directory to store downloaded files
#    [DOWNLOAD_COMMAND cmd...]   # Command to download source tree
#    [DOWNLOAD_NO_PROGRESS 1]    # Disable download progress reports
#    [CVS_REPOSITORY cvsroot]    # CVSROOT of CVS repository
#    [CVS_MODULE mod]            # Module to checkout from CVS repo
#    [CVS_TAG tag]               # Tag to checkout from CVS repo
#    [SVN_REPOSITORY url]        # URL of Subversion repo
#    [SVN_REVISION -r<rev>]      # Revision to checkout from Subversion repo
#    [SVN_USERNAME john ]        # Username for Subversion checkout and update
#    [SVN_PASSWORD doe ]         # Password for Subversion checkout and update
#    [SVN_TRUST_CERT 1 ]         # Trust the Subversion server site certificate
#    [GIT_REPOSITORY url]        # URL of git repo
#    [GIT_TAG tag]               # Git branch name, commit id or tag
#    [GIT_SUBMODULES modules...] # Git submodules that shall be updated, all if empty
#    [HG_REPOSITORY url]         # URL of mercurial repo
#    [HG_TAG tag]                # Mercurial branch name, commit id or tag
#    [URL /.../src.tgz]          # Full path or URL of source
#    [URL_HASH ALGO=value]       # Hash of file at URL
#    [URL_MD5 md5]               # Equivalent to URL_HASH MD5=md5
#    [TLS_VERIFY bool]           # Should certificate for https be checked
#    [TLS_CAINFO file]           # Path to a certificate authority file
#    [TIMEOUT seconds]           # Time allowed for file download operations
#   #--Update/Patch step----------
#    [UPDATE_COMMAND cmd...]     # Source work-tree update command
#    [PATCH_COMMAND cmd...]      # Command to patch downloaded source
#   #--Configure step-------------
#    [SOURCE_DIR dir]            # Source dir to be used for build
#    [CONFIGURE_COMMAND cmd...]  # Build tree configuration command
#    [CMAKE_COMMAND /.../cmake]  # Specify alternative cmake executable
#    [CMAKE_GENERATOR gen]       # Specify generator for native build
#    [CMAKE_GENERATOR_PLATFORM p] # Generator-specific platform name
#    [CMAKE_GENERATOR_TOOLSET t] # Generator-specific toolset name
#    [CMAKE_ARGS args...]        # Arguments to CMake command line
#    [CMAKE_CACHE_ARGS args...]  # Initial cache arguments, of the form -Dvar:string=on
#   #--Build step-----------------
#    [BINARY_DIR dir]            # Specify build dir location
#    [BUILD_COMMAND cmd...]      # Command to drive the native build
#    [BUILD_IN_SOURCE 1]         # Use source dir for build dir
#    [BUILD_ALWAYS 1]            # No stamp file, build step always runs
#   #--Install step---------------
#    [INSTALL_DIR dir]           # Installation prefix
#    [INSTALL_COMMAND cmd...]    # Command to drive install after build
#   #--Test step------------------
#    [TEST_BEFORE_INSTALL 1]     # Add test step executed before install step
#    [TEST_AFTER_INSTALL 1]      # Add test step executed after install step
#    [TEST_COMMAND cmd...]       # Command to drive test
#   #--Output logging-------------
#    [LOG_DOWNLOAD 1]            # Wrap download in script to log output
#    [LOG_UPDATE 1]              # Wrap update in script to log output
#    [LOG_CONFIGURE 1]           # Wrap configure in script to log output
#    [LOG_BUILD 1]               # Wrap build in script to log output
#    [LOG_TEST 1]                # Wrap test in script to log output
#    [LOG_INSTALL 1]             # Wrap install in script to log output
#   #--Custom targets-------------
#    [STEP_TARGETS st1 st2 ...]  # Generate custom targets for these steps
#    )
#
# The ``*_DIR`` options specify directories for the project, with default
# directories computed as follows.  If the ``PREFIX`` option is given to
# ``ExternalProject_Add()`` or the ``EP_PREFIX`` directory property is set,
# then an external project is built and installed under the specified prefix::
#
#  TMP_DIR      = <prefix>/tmp
#  STAMP_DIR    = <prefix>/src/<name>-stamp
#  DOWNLOAD_DIR = <prefix>/src
#  SOURCE_DIR   = <prefix>/src/<name>
#  BINARY_DIR   = <prefix>/src/<name>-build
#  INSTALL_DIR  = <prefix>
#
# Otherwise, if the ``EP_BASE`` directory property is set then components
# of an external project are stored under the specified base::
#
#  TMP_DIR      = <base>/tmp/<name>
#  STAMP_DIR    = <base>/Stamp/<name>
#  DOWNLOAD_DIR = <base>/Download/<name>
#  SOURCE_DIR   = <base>/Source/<name>
#  BINARY_DIR   = <base>/Build/<name>
#  INSTALL_DIR  = <base>/Install/<name>
#
# If no ``PREFIX``, ``EP_PREFIX``, or ``EP_BASE`` is specified then the
# default is to set ``PREFIX`` to ``<name>-prefix``.  Relative paths are
# interpreted with respect to the build directory corresponding to the
# source directory in which ``ExternalProject_Add`` is invoked.
#
# If ``SOURCE_DIR`` is explicitly set to an existing directory the project
# will be built from it.  Otherwise a download step must be specified
# using one of the ``DOWNLOAD_COMMAND``, ``CVS_*``, ``SVN_*``, or ``URL``
# options.  The ``URL`` option may refer locally to a directory or source
# tarball, or refer to a remote tarball (e.g. ``http://.../src.tgz``).
#
# The ``ExternalProject_Add_Step`` function adds a custom step to an
# external project:
#
# .. code-block:: cmake
#
#  ExternalProject_Add_Step(<name> <step> # Names of project and custom step
#    [COMMAND cmd...]        # Command line invoked by this step
#    [COMMENT "text..."]     # Text printed when step executes
#    [DEPENDEES steps...]    # Steps on which this step depends
#    [DEPENDERS steps...]    # Steps that depend on this step
#    [DEPENDS files...]      # Files on which this step depends
#    [ALWAYS 1]              # No stamp file, step always runs
#    [EXCLUDE_FROM_MAIN 1]   # Main target does not depend on this step
#    [WORKING_DIRECTORY dir] # Working directory for command
#    [LOG 1]                 # Wrap step in script to log output
#    )
#
# The command line, comment, and working directory of every standard and
# custom step is processed to replace tokens ``<SOURCE_DIR>``,
# ``<BINARY_DIR>``, ``<INSTALL_DIR>``, and ``<TMP_DIR>`` with
# corresponding property values.
#
# Any builtin step that specifies a ``<step>_COMMAND cmd...`` or custom
# step that specifies a ``COMMAND cmd...`` may specify additional command
# lines using the form ``COMMAND cmd...``.  At build time the commands
# will be executed in order and aborted if any one fails.  For example::
#
#  ... BUILD_COMMAND make COMMAND echo done ...
#
# specifies to run ``make`` and then ``echo done`` during the build step.
# Whether the current working directory is preserved between commands is
# not defined.  Behavior of shell operators like ``&&`` is not defined.
#
# The ``ExternalProject_Get_Property`` function retrieves external project
# target properties::
#
#  ExternalProject_Get_Property(<name> [prop1 [prop2 [...]]])
#
# It stores property values in variables of the same name.  Property
# names correspond to the keyword argument names of
# ``ExternalProject_Add``.
#
# The ``ExternalProject_Add_StepTargets`` function generates custom
# targets for the steps listed::
#
#  ExternalProject_Add_StepTargets(<name> [step1 [step2 [...]]])
#
# If ``STEP_TARGETS`` is set then ``ExternalProject_Add_StepTargets`` is
# automatically called at the end of matching calls to
# ``ExternalProject_Add_Step``.  Pass ``STEP_TARGETS`` explicitly to
# individual ``ExternalProject_Add`` calls, or implicitly to all
# ``ExternalProject_Add`` calls by setting the directory property
# ``EP_STEP_TARGETS``.
#
# If ``STEP_TARGETS`` is not set, clients may still manually call
# ``ExternalProject_Add_StepTargets`` after calling
# ``ExternalProject_Add`` or ``ExternalProject_Add_Step``.
#
# This functionality is provided to make it easy to drive the steps
# independently of each other by specifying targets on build command
# lines.  For example, you may be submitting to a sub-project based
# dashboard, where you want to drive the configure portion of the build,
# then submit to the dashboard, followed by the build portion, followed
# by tests.  If you invoke a custom target that depends on a step
# halfway through the step dependency chain, then all the previous steps
# will also run to ensure everything is up to date.
#
# For example, to drive configure, build and test steps independently
# for each ``ExternalProject_Add`` call in your project, write the following
# line prior to any ``ExternalProject_Add`` calls in your ``CMakeLists.txt``
# file::
#
#  set_property(DIRECTORY PROPERTY EP_STEP_TARGETS configure build test)

#=============================================================================
# Copyright 2008-2013 Kitware, Inc.
#
# Distributed under the OSI-approved BSD License (the "License");
# see accompanying file Copyright.txt for details.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
#=============================================================================
# (To distribute this file outside of CMake, substitute the full
#  License text for the above reference.)

# Pre-compute a regex to match documented keywords for each command.
math(EXPR _ep_documentation_line_count "${CMAKE_CURRENT_LIST_LINE} - 16")
file(STRINGS "${CMAKE_CURRENT_LIST_FILE}" lines
     LIMIT_COUNT ${_ep_documentation_line_count}
     REGEX "^#  (  \\[[A-Z0-9_]+ [^]]*\\] +#.*$|[A-Za-z0-9_]+\\()")
foreach(line IN LISTS lines)
  if("${line}" MATCHES "^#  ([A-Za-z0-9_]+)\\(")
    if(_ep_func)
      set(_ep_keywords_${_ep_func} "${_ep_keywords_${_ep_func}})$")
    endif()
    set(_ep_func "${CMAKE_MATCH_1}")
    #message("function [${_ep_func}]")
    set(_ep_keywords_${_ep_func} "^(")
    set(_ep_keyword_sep)
  else()
    string(REGEX REPLACE "^#    \\[([A-Z0-9_]+) .*" "\\1" _ep_key "${line}")
    #message("  keyword [${_ep_key}]")
    set(_ep_keywords_${_ep_func}
      "${_ep_keywords_${_ep_func}}${_ep_keyword_sep}${_ep_key}")
    set(_ep_keyword_sep "|")
  endif()
endforeach()
if(_ep_func)
  set(_ep_keywords_${_ep_func} "${_ep_keywords_${_ep_func}})$")
endif()

# Save regex matching supported hash algorithm names.
set(_ep_hash_algos "MD5|SHA1|SHA224|SHA256|SHA384|SHA512")
set(_ep_hash_regex "^(${_ep_hash_algos})=([0-9A-Fa-f]+)$")

function(_ep_parse_arguments f name ns args)
  # Transfer the arguments to this function into target properties for the
  # new custom target we just added so that we can set up all the build steps
  # correctly based on target properties.
  #
  # We loop through ARGN and consider the namespace starting with an
  # upper-case letter followed by at least two more upper-case letters,
  # numbers or underscores to be keywords.
  set(key)

  foreach(arg IN LISTS args)
    set(is_value 1)

    if(arg MATCHES "^[A-Z][A-Z0-9_][A-Z0-9_]+$" AND
        NOT (("x${arg}x" STREQUAL "x${key}x") AND ("x${key}x" STREQUAL "xCOMMANDx")) AND
        NOT arg MATCHES "^(TRUE|FALSE)$")
      if(_ep_keywords_${f} AND arg MATCHES "${_ep_keywords_${f}}")
        set(is_value 0)
      endif()
    endif()

    if(is_value)
      if(key)
        # Value
        if(NOT arg STREQUAL "")
          set_property(TARGET ${name} APPEND PROPERTY ${ns}${key} "${arg}")
        else()
          get_property(have_key TARGET ${name} PROPERTY ${ns}${key} SET)
          if(have_key)
            get_property(value TARGET ${name} PROPERTY ${ns}${key})
            set_property(TARGET ${name} PROPERTY ${ns}${key} "${value};${arg}")
          else()
            set_property(TARGET ${name} PROPERTY ${ns}${key} "${arg}")
          endif()
        endif()
      else()
        # Missing Keyword
        message(AUTHOR_WARNING "value '${arg}' with no previous keyword in ${f}")
      endif()
    else()
      set(key "${arg}")
    endif()
  endforeach()
endfunction()


define_property(DIRECTORY PROPERTY "EP_BASE" INHERITED
  BRIEF_DOCS "Base directory for External Project storage."
  FULL_DOCS
  "See documentation of the ExternalProject_Add() function in the "
  "ExternalProject module."
  )

define_property(DIRECTORY PROPERTY "EP_PREFIX" INHERITED
  BRIEF_DOCS "Top prefix for External Project storage."
  FULL_DOCS
  "See documentation of the ExternalProject_Add() function in the "
  "ExternalProject module."
  )

define_property(DIRECTORY PROPERTY "EP_STEP_TARGETS" INHERITED
  BRIEF_DOCS
  "List of ExternalProject steps that automatically get corresponding targets"
  FULL_DOCS
  "See documentation of the ExternalProject_Add_StepTargets() function in the "
  "ExternalProject module."
  )


function(_ep_write_gitclone_script script_filename source_dir git_EXECUTABLE git_repository git_tag git_submodules src_name work_dir gitclone_infofile gitclone_stampfile)
  file(WRITE ${script_filename}
"if(\"${git_tag}\" STREQUAL \"\")
  message(FATAL_ERROR \"Tag for git checkout should not be empty.\")
endif()

set(run 0)

if(\"${gitclone_infofile}\" IS_NEWER_THAN \"${gitclone_stampfile}\")
  set(run 1)
endif()

if(NOT run)
  message(STATUS \"Avoiding repeated git clone, stamp file is up to date: '${gitclone_stampfile}'\")
  return()
endif()

execute_process(
  COMMAND \${CMAKE_COMMAND} -E remove_directory \"${source_dir}\"
  RESULT_VARIABLE error_code
  )
if(error_code)
  message(FATAL_ERROR \"Failed to remove directory: '${source_dir}'\")
endif()

# try the clone 3 times incase there is an odd git clone issue
set(error_code 1)
set(number_of_tries 0)
while(error_code AND number_of_tries LESS 3)
  execute_process(
    COMMAND \"${git_EXECUTABLE}\" clone \"${git_repository}\" \"${src_name}\"
    WORKING_DIRECTORY \"${work_dir}\"
    RESULT_VARIABLE error_code
    )
  math(EXPR number_of_tries \"\${number_of_tries} + 1\")
endwhile()
if(number_of_tries GREATER 1)
  message(STATUS \"Had to git clone more than once:
          \${number_of_tries} times.\")
endif()
if(error_code)
  message(FATAL_ERROR \"Failed to clone repository: '${git_repository}'\")
endif()

execute_process(
  COMMAND \"${git_EXECUTABLE}\" checkout ${git_tag}
  WORKING_DIRECTORY \"${work_dir}/${src_name}\"
  RESULT_VARIABLE error_code
  )
if(error_code)
  message(FATAL_ERROR \"Failed to checkout tag: '${git_tag}'\")
endif()

execute_process(
  COMMAND \"${git_EXECUTABLE}\" submodule init
  WORKING_DIRECTORY \"${work_dir}/${src_name}\"
  RESULT_VARIABLE error_code
  )
if(error_code)
  message(FATAL_ERROR \"Failed to init submodules in: '${work_dir}/${src_name}'\")
endif()

execute_process(
  COMMAND \"${git_EXECUTABLE}\" submodule update --recursive ${git_submodules}
  WORKING_DIRECTORY \"${work_dir}/${src_name}\"
  RESULT_VARIABLE error_code
  )
if(error_code)
  message(FATAL_ERROR \"Failed to update submodules in: '${work_dir}/${src_name}'\")
endif()

# Complete success, update the script-last-run stamp file:
#
execute_process(
  COMMAND \${CMAKE_COMMAND} -E copy
    \"${gitclone_infofile}\"
    \"${gitclone_stampfile}\"
  WORKING_DIRECTORY \"${work_dir}/${src_name}\"
  RESULT_VARIABLE error_code
  )
if(error_code)
  message(FATAL_ERROR \"Failed to copy script-last-run stamp file: '${gitclone_stampfile}'\")
endif()

"
)

endfunction()

function(_ep_write_hgclone_script script_filename source_dir hg_EXECUTABLE hg_repository hg_tag src_name work_dir hgclone_infofile hgclone_stampfile)
  file(WRITE ${script_filename}
"if(\"${hg_tag}\" STREQUAL \"\")
  message(FATAL_ERROR \"Tag for hg checkout should not be empty.\")
endif()

set(run 0)

if(\"${hgclone_infofile}\" IS_NEWER_THAN \"${hgclone_stampfile}\")
  set(run 1)
endif()

if(NOT run)
  message(STATUS \"Avoiding repeated hg clone, stamp file is up to date: '${hgclone_stampfile}'\")
  return()
endif()

execute_process(
  COMMAND \${CMAKE_COMMAND} -E remove_directory \"${source_dir}\"
  RESULT_VARIABLE error_code
  )
if(error_code)
  message(FATAL_ERROR \"Failed to remove directory: '${source_dir}'\")
endif()

execute_process(
  COMMAND \"${hg_EXECUTABLE}\" clone \"${hg_repository}\" \"${src_name}\"
  WORKING_DIRECTORY \"${work_dir}\"
  RESULT_VARIABLE error_code
  )
if(error_code)
  message(FATAL_ERROR \"Failed to clone repository: '${hg_repository}'\")
endif()

execute_process(
  COMMAND \"${hg_EXECUTABLE}\" update ${hg_tag}
  WORKING_DIRECTORY \"${work_dir}/${src_name}\"
  RESULT_VARIABLE error_code
  )
if(error_code)
  message(FATAL_ERROR \"Failed to checkout tag: '${hg_tag}'\")
endif()

# Complete success, update the script-last-run stamp file:
#
execute_process(
  COMMAND \${CMAKE_COMMAND} -E copy
    \"${hgclone_infofile}\"
    \"${hgclone_stampfile}\"
  WORKING_DIRECTORY \"${work_dir}/${src_name}\"
  RESULT_VARIABLE error_code
  )
if(error_code)
  message(FATAL_ERROR \"Failed to copy script-last-run stamp file: '${hgclone_stampfile}'\")
endif()

"
)

endfunction()


function(_ep_write_gitupdate_script script_filename git_EXECUTABLE git_tag git_submodules git_repository work_dir)
  file(WRITE ${script_filename}
"if(\"${git_tag}\" STREQUAL \"\")
  message(FATAL_ERROR \"Tag for git checkout should not be empty.\")
endif()

execute_process(
  COMMAND \"${git_EXECUTABLE}\" rev-list --max-count=1 HEAD
  WORKING_DIRECTORY \"${work_dir}\"
  RESULT_VARIABLE error_code
  OUTPUT_VARIABLE head_sha
  OUTPUT_STRIP_TRAILING_WHITESPACE
  )
if(error_code)
  message(FATAL_ERROR \"Failed to get the hash for HEAD\")
endif()

execute_process(
  COMMAND \"${git_EXECUTABLE}\" show-ref ${git_tag}
  WORKING_DIRECTORY \"${work_dir}\"
  OUTPUT_VARIABLE show_ref_output
  )
# If a remote ref is asked for, which can possibly move around,
# we must always do a fetch and checkout.
if(\"\${show_ref_output}\" MATCHES \"remotes\")
  set(is_remote_ref 1)
else()
  set(is_remote_ref 0)
endif()

# Tag is in the form <remote>/<tag> (i.e. origin/master) we must strip
# the remote from the tag.
if(\"\${show_ref_output}\" MATCHES \"refs/remotes/${git_tag}\")
  string(REGEX MATCH \"^([^/]+)/(.+)$\" _unused \"${git_tag}\")
  set(git_remote \"\${CMAKE_MATCH_1}\")
  set(git_tag \"\${CMAKE_MATCH_2}\")
else()
  set(git_remote \"origin\")
  set(git_tag \"${git_tag}\")
endif()

# This will fail if the tag does not exist (it probably has not been fetched
# yet).
execute_process(
  COMMAND \"${git_EXECUTABLE}\" rev-list --max-count=1 ${git_tag}
  WORKING_DIRECTORY \"${work_dir}\"
  RESULT_VARIABLE error_code
  OUTPUT_VARIABLE tag_sha
  OUTPUT_STRIP_TRAILING_WHITESPACE
  )

# Is the hash checkout out that we want?
if(error_code OR is_remote_ref OR NOT (\"\${tag_sha}\" STREQUAL \"\${head_sha}\"))
  execute_process(
    COMMAND \"${git_EXECUTABLE}\" fetch
    WORKING_DIRECTORY \"${work_dir}\"
    RESULT_VARIABLE error_code
    )
  if(error_code)
    message(FATAL_ERROR \"Failed to fetch repository '${git_repository}'\")
  endif()

  if(is_remote_ref)
    # Check if stash is needed
    execute_process(
      COMMAND \"${git_EXECUTABLE}\" status --porcelain
      WORKING_DIRECTORY \"${work_dir}\"
      RESULT_VARIABLE error_code
      OUTPUT_VARIABLE repo_status
      )
    if(error_code)
      message(FATAL_ERROR \"Failed to get the status\")
    endif()
    string(LENGTH \"\${repo_status}\" need_stash)

    # If not in clean state, stash changes in order to be able to be able to
    # perform git pull --rebase
    if(need_stash)
      execute_process(
        COMMAND \"${git_EXECUTABLE}\" stash save --all --quiet
        WORKING_DIRECTORY \"${work_dir}\"
        RESULT_VARIABLE error_code
        )
      if(error_code)
        message(FATAL_ERROR \"Failed to stash changes\")
      endif()
    endif()

    # Pull changes from the remote branch
    execute_process(
      COMMAND \"${git_EXECUTABLE}\" rebase \${git_remote}/\${git_tag}
      WORKING_DIRECTORY \"${work_dir}\"
      RESULT_VARIABLE error_code
      )
    if(error_code)
      # Rebase failed: Restore previous state.
      execute_process(
        COMMAND \"${git_EXECUTABLE}\" rebase --abort
        WORKING_DIRECTORY \"${work_dir}\"
      )
      if(need_stash)
        execute_process(
          COMMAND \"${git_EXECUTABLE}\" stash pop --index --quiet
          WORKING_DIRECTORY \"${work_dir}\"
          )
      endif()
      message(FATAL_ERROR \"\\nFailed to rebase in: '${work_dir}/${src_name}'.\\nYou will have to resolve the conflicts manually\")
    endif()

    if(need_stash)
      execute_process(
        COMMAND \"${git_EXECUTABLE}\" stash pop --index --quiet
        WORKING_DIRECTORY \"${work_dir}\"
        RESULT_VARIABLE error_code
        )
      if(error_code)
        # Stash pop --index failed: Try again dropping the index
        execute_process(
          COMMAND \"${git_EXECUTABLE}\" reset --hard --quiet
          WORKING_DIRECTORY \"${work_dir}\"
          RESULT_VARIABLE error_code
          )
        execute_process(
          COMMAND \"${git_EXECUTABLE}\" stash pop --quiet
          WORKING_DIRECTORY \"${work_dir}\"
          RESULT_VARIABLE error_code
          )
        if(error_code)
          # Stash pop failed: Restore previous state.
          execute_process(
            COMMAND \"${git_EXECUTABLE}\" reset --hard --quiet \${head_sha}
            WORKING_DIRECTORY \"${work_dir}\"
          )
          execute_process(
            COMMAND \"${git_EXECUTABLE}\" stash pop --index --quiet
            WORKING_DIRECTORY \"${work_dir}\"
          )
          message(FATAL_ERROR \"\\nFailed to unstash changes in: '${work_dir}/${src_name}'.\\nYou will have to resolve the conflicts manually\")
        endif()
      endif()
    endif()
  else()
    execute_process(
      COMMAND \"${git_EXECUTABLE}\" checkout ${git_tag}
      WORKING_DIRECTORY \"${work_dir}\"
      RESULT_VARIABLE error_code
      )
    if(error_code)
      message(FATAL_ERROR \"Failed to checkout tag: '${git_tag}'\")
    endif()
  endif()

  execute_process(
    COMMAND \"${git_EXECUTABLE}\" submodule update --recursive ${git_submodules}
    WORKING_DIRECTORY \"${work_dir}/${src_name}\"
    RESULT_VARIABLE error_code
    )
  if(error_code)
    message(FATAL_ERROR \"Failed to update submodules in: '${work_dir}/${src_name}'\")
  endif()
endif()

"
)

endfunction(_ep_write_gitupdate_script)

function(_ep_write_downloadfile_script script_filename remote local timeout no_progress hash tls_verify tls_cainfo)
  if(timeout)
    set(timeout_args TIMEOUT ${timeout})
    set(timeout_msg "${timeout} seconds")
  else()
    set(timeout_args "# no TIMEOUT")
    set(timeout_msg "none")
  endif()

  if(no_progress)
    set(show_progress "")
  else()
    set(show_progress "SHOW_PROGRESS")
  endif()

  # check for curl globals in the project
  if(DEFINED CMAKE_TLS_VERIFY)
    set(tls_verify "set(CMAKE_TLS_VERIFY ${CMAKE_TLS_VERIFY})")
  endif()
  if(DEFINED CMAKE_TLS_CAINFO)
    set(tls_cainfo "set(CMAKE_TLS_CAINFO \"${CMAKE_TLS_CAINFO}\")")
  endif()

  # now check for curl locals so that the local values
  # will override the globals

  # check for tls_verify argument
  string(LENGTH "${tls_verify}" tls_verify_len)
  if(tls_verify_len GREATER 0)
    set(tls_verify "set(CMAKE_TLS_VERIFY ${tls_verify})")
  endif()
  # check for tls_cainfo argument
  string(LENGTH "${tls_cainfo}" tls_cainfo_len)
  if(tls_cainfo_len GREATER 0)
    set(tls_cainfo "set(CMAKE_TLS_CAINFO \"${tls_cainfo}\")")
  endif()

  file(WRITE ${script_filename}
"message(STATUS \"downloading...
     src='${remote}'
     dst='${local}'
     timeout='${timeout_msg}'\")

${tls_verify}
${tls_cainfo}

file(DOWNLOAD
  \"${remote}\"
  \"${local}\"
  ${show_progress}
  ${timeout_args}
  STATUS status
  LOG log)

list(GET status 0 status_code)
list(GET status 1 status_string)

if(NOT status_code EQUAL 0)
  message(FATAL_ERROR \"error: downloading '${remote}' failed
  status_code: \${status_code}
  status_string: \${status_string}
  log: \${log}
\")
endif()

message(STATUS \"downloading... done\")
"
)

endfunction()


function(_ep_write_verifyfile_script script_filename local hash retries download_script)
  if("${hash}" MATCHES "${_ep_hash_regex}")
    set(algo "${CMAKE_MATCH_1}")
    string(TOLOWER "${CMAKE_MATCH_2}" expect_value)
    set(script_content "set(expect_value \"${expect_value}\")
set(attempt 0)
set(succeeded 0)
while(\${attempt} LESS ${retries} OR \${attempt} EQUAL ${retries} AND NOT \${succeeded})
  file(${algo} \"\${file}\" actual_value)
  if(\"\${actual_value}\" STREQUAL \"\${expect_value}\")
    set(succeeded 1)
  elseif(\${attempt} LESS ${retries})
    message(STATUS \"${algo} hash of \${file}
does not match expected value
  expected: \${expect_value}
    actual: \${actual_value}
Retrying download.
\")
    file(REMOVE \"\${file}\")
    execute_process(COMMAND \${CMAKE_COMMAND} -P \"${download_script}\")
  endif()
  math(EXPR attempt \"\${attempt} + 1\")
endwhile()

if(\${succeeded})
  message(STATUS \"verifying file... done\")
else()
  message(FATAL_ERROR \"error: ${algo} hash of
  \${file}
does not match expected value
  expected: \${expect_value}
    actual: \${actual_value}
\")
endif()")
  else()
    set(script_content "message(STATUS \"verifying file... warning: did not verify file - no URL_HASH specified?\")")
  endif()
  file(WRITE ${script_filename} "set(file \"${local}\")
message(STATUS \"verifying file...
     file='\${file}'\")
${script_content}
")
endfunction()


function(_ep_write_extractfile_script script_filename name filename directory)
  set(args "")

  if(filename MATCHES "(\\.|=)(7z|tar\\.bz2|tar\\.gz|tar\\.xz|tbz2|tgz|txz|zip)$")
    set(args xfz)
  endif()

  if(filename MATCHES "(\\.|=)tar$")
    set(args xf)
  endif()

  if(args STREQUAL "")
    message(SEND_ERROR "error: do not know how to extract '${filename}' -- known types are .7z, .tar, .tar.bz2, .tar.gz, .tar.xz, .tbz2, .tgz, .txz and .zip")
    return()
  endif()

  file(WRITE ${script_filename}
"# Make file names absolute:
#
get_filename_component(filename \"${filename}\" ABSOLUTE)
get_filename_component(directory \"${directory}\" ABSOLUTE)

message(STATUS \"extracting...
     src='\${filename}'
     dst='\${directory}'\")

if(NOT EXISTS \"\${filename}\")
  message(FATAL_ERROR \"error: file to extract does not exist: '\${filename}'\")
endif()

# Prepare a space for extracting:
#
set(i 1234)
while(EXISTS \"\${directory}/../ex-${name}\${i}\")
  math(EXPR i \"\${i} + 1\")
endwhile()
set(ut_dir \"\${directory}/../ex-${name}\${i}\")
file(MAKE_DIRECTORY \"\${ut_dir}\")

# Extract it:
#
message(STATUS \"extracting... [tar ${args}]\")
execute_process(COMMAND \${CMAKE_COMMAND} -E tar ${args} \${filename}
  WORKING_DIRECTORY \${ut_dir}
  RESULT_VARIABLE rv)

if(NOT rv EQUAL 0)
  message(STATUS \"extracting... [error clean up]\")
  file(REMOVE_RECURSE \"\${ut_dir}\")
  message(FATAL_ERROR \"error: extract of '\${filename}' failed\")
endif()

# Analyze what came out of the tar file:
#
message(STATUS \"extracting... [analysis]\")
file(GLOB contents \"\${ut_dir}/*\")
list(LENGTH contents n)
if(NOT n EQUAL 1 OR NOT IS_DIRECTORY \"\${contents}\")
  set(contents \"\${ut_dir}\")
endif()

# Move \"the one\" directory to the final directory:
#
message(STATUS \"extracting... [rename]\")
file(REMOVE_RECURSE \${directory})
get_filename_component(contents \${contents} ABSOLUTE)
file(RENAME \${contents} \${directory})

# Clean up:
#
message(STATUS \"extracting... [clean up]\")
file(REMOVE_RECURSE \"\${ut_dir}\")

message(STATUS \"extracting... done\")
"
)

endfunction()


function(_ep_set_directories name)
  get_property(prefix TARGET ${name} PROPERTY _EP_PREFIX)
  if(NOT prefix)
    get_property(prefix DIRECTORY PROPERTY EP_PREFIX)
    if(NOT prefix)
      get_property(base DIRECTORY PROPERTY EP_BASE)
      if(NOT base)
        set(prefix "${name}-prefix")
      endif()
    endif()
  endif()
  if(prefix)
    set(tmp_default "${prefix}/tmp")
    set(download_default "${prefix}/src")
    set(source_default "${prefix}/src/${name}")
    set(binary_default "${prefix}/src/${name}-build")
    set(stamp_default "${prefix}/src/${name}-stamp")
    set(install_default "${prefix}")
  else()
    set(tmp_default "${base}/tmp/${name}")
    set(download_default "${base}/Download/${name}")
    set(source_default "${base}/Source/${name}")
    set(binary_default "${base}/Build/${name}")
    set(stamp_default "${base}/Stamp/${name}")
    set(install_default "${base}/Install/${name}")
  endif()
  get_property(build_in_source TARGET ${name} PROPERTY _EP_BUILD_IN_SOURCE)
  if(build_in_source)
    get_property(have_binary_dir TARGET ${name} PROPERTY _EP_BINARY_DIR SET)
    if(have_binary_dir)
      message(FATAL_ERROR
        "External project ${name} has both BINARY_DIR and BUILD_IN_SOURCE!")
    endif()
  endif()
  set(top "${CMAKE_CURRENT_BINARY_DIR}")
  set(places stamp download source binary install tmp)
  foreach(var ${places})
    string(TOUPPER "${var}" VAR)
    get_property(${var}_dir TARGET ${name} PROPERTY _EP_${VAR}_DIR)
    if(NOT ${var}_dir)
      set(${var}_dir "${${var}_default}")
    endif()
    if(NOT IS_ABSOLUTE "${${var}_dir}")
      get_filename_component(${var}_dir "${top}/${${var}_dir}" ABSOLUTE)
    endif()
    set_property(TARGET ${name} PROPERTY _EP_${VAR}_DIR "${${var}_dir}")
  endforeach()
  if(build_in_source)
    get_property(source_dir TARGET ${name} PROPERTY _EP_SOURCE_DIR)
    set_property(TARGET ${name} PROPERTY _EP_BINARY_DIR "${source_dir}")
  endif()

  # Make the directories at CMake configure time *and* add a custom command
  # to make them at build time. They need to exist at makefile generation
  # time for Borland make and wmake so that CMake may generate makefiles
  # with "cd C:\short\paths\with\no\spaces" commands in them.
  #
  # Additionally, the add_custom_command is still used in case somebody
  # removes one of the necessary directories and tries to rebuild without
  # re-running cmake.
  foreach(var ${places})
    string(TOUPPER "${var}" VAR)
    get_property(dir TARGET ${name} PROPERTY _EP_${VAR}_DIR)
    file(MAKE_DIRECTORY "${dir}")
    if(NOT EXISTS "${dir}")
      message(FATAL_ERROR "dir '${dir}' does not exist after file(MAKE_DIRECTORY)")
    endif()
  endforeach()
endfunction()


# IMPORTANT: this MUST be a macro and not a function because of the
# in-place replacements that occur in each ${var}
#
macro(_ep_replace_location_tags target_name)
  set(vars ${ARGN})
  foreach(var ${vars})
    if(${var})
      foreach(dir SOURCE_DIR BINARY_DIR INSTALL_DIR TMP_DIR)
        get_property(val TARGET ${target_name} PROPERTY _EP_${dir})
        string(REPLACE "<${dir}>" "${val}" ${var} "${${var}}")
      endforeach()
    endif()
  endforeach()
endmacro()


function(_ep_write_initial_cache target_name script_filename args)
  # Write out values into an initial cache, that will be passed to CMake with -C
  set(script_initial_cache "")
  set(regex "^([^:]+):([^=]+)=(.*)$")
  set(setArg "")
  foreach(line ${args})
    if("${line}" MATCHES "^-D(.*)")
      set(line "${CMAKE_MATCH_1}")
      if(setArg)
        # This is required to build up lists in variables, or complete an entry
        set(setArg "${setArg}${accumulator}\" CACHE ${type} \"Initial cache\" FORCE)")
        set(script_initial_cache "${script_initial_cache}\n${setArg}")
        set(accumulator "")
        set(setArg "")
      endif()
      if("${line}" MATCHES "${regex}")
        set(name "${CMAKE_MATCH_1}")
        set(type "${CMAKE_MATCH_2}")
        set(value "${CMAKE_MATCH_3}")
        set(setArg "set(${name} \"${value}")
      else()
        message(WARNING "Line '${line}' does not match regex. Ignoring.")
      endif()
    else()
      # Assume this is a list to append to the last var
      set(accumulator "${accumulator};${line}")
    endif()
  endforeach()
  # Catch the final line of the args
  if(setArg)
    set(setArg "${setArg}${accumulator}\" CACHE ${type} \"Initial cache\" FORCE)")
    set(script_initial_cache "${script_initial_cache}\n${setArg}")
  endif()
  # Replace location tags.
  _ep_replace_location_tags(${target_name} script_initial_cache)
  # Write out the initial cache file to the location specified.
  if(NOT EXISTS "${script_filename}.in")
    file(WRITE "${script_filename}.in" "\@script_initial_cache\@\n")
  endif()
  configure_file("${script_filename}.in" "${script_filename}")
endfunction()


function(ExternalProject_Get_Property name)
  foreach(var ${ARGN})
    string(TOUPPER "${var}" VAR)
    get_property(${var} TARGET ${name} PROPERTY _EP_${VAR})
    if(NOT ${var})
      message(FATAL_ERROR "External project \"${name}\" has no ${var}")
    endif()
    set(${var} "${${var}}" PARENT_SCOPE)
  endforeach()
endfunction()


function(_ep_get_configure_command_id name cfg_cmd_id_var)
  get_target_property(cmd ${name} _EP_CONFIGURE_COMMAND)

  if(cmd STREQUAL "")
    # Explicit empty string means no configure step for this project
    set(${cfg_cmd_id_var} "none" PARENT_SCOPE)
  else()
    if(NOT cmd)
      # Default is "use cmake":
      set(${cfg_cmd_id_var} "cmake" PARENT_SCOPE)
    else()
      # Otherwise we have to analyze the value:
      if(cmd MATCHES "^[^;]*/configure")
        set(${cfg_cmd_id_var} "configure" PARENT_SCOPE)
      elseif(cmd MATCHES "^[^;]*/cmake" AND NOT cmd MATCHES ";-[PE];")
        set(${cfg_cmd_id_var} "cmake" PARENT_SCOPE)
      elseif(cmd MATCHES "config")
        set(${cfg_cmd_id_var} "configure" PARENT_SCOPE)
      else()
        set(${cfg_cmd_id_var} "unknown:${cmd}" PARENT_SCOPE)
      endif()
    endif()
  endif()
endfunction()


function(_ep_get_build_command name step cmd_var)
  set(cmd "${${cmd_var}}")
  if(NOT cmd)
    set(args)
    _ep_get_configure_command_id(${name} cfg_cmd_id)
    if(cfg_cmd_id STREQUAL "cmake")
      # CMake project.  Select build command based on generator.
      get_target_property(cmake_generator ${name} _EP_CMAKE_GENERATOR)
      if("${CMAKE_GENERATOR}" MATCHES "Make" AND
         ("${cmake_generator}" MATCHES "Make" OR NOT cmake_generator))
        # The project uses the same Makefile generator.  Use recursive make.
        set(cmd "$(MAKE)")
        if(step STREQUAL "INSTALL")
          set(args install)
        endif()
        if(step STREQUAL "TEST")
          set(args test)
        endif()
      else()
        # Drive the project with "cmake --build".
        get_target_property(cmake_command ${name} _EP_CMAKE_COMMAND)
        if(cmake_command)
          set(cmd "${cmake_command}")
        else()
          set(cmd "${CMAKE_COMMAND}")
        endif()
        set(args --build ${binary_dir} --config ${CMAKE_CFG_INTDIR})
        if(step STREQUAL "INSTALL")
          list(APPEND args --target install)
        endif()
        # But for "TEST" drive the project with corresponding "ctest".
        if(step STREQUAL "TEST")
          string(REGEX REPLACE "^(.*/)cmake([^/]*)$" "\\1ctest\\2" cmd "${cmd}")
          set(args "")
        endif()
      endif()
    else()
      # Non-CMake project.  Guess "make" and "make install" and "make test".
      if("${CMAKE_GENERATOR}" MATCHES "Makefiles")
        # Try to get the parallel arguments
        set(cmd "$(MAKE)")
      else()
        set(cmd "make")
      endif()
      if(step STREQUAL "INSTALL")
        set(args install)
      endif()
      if(step STREQUAL "TEST")
        set(args test)
      endif()
    endif()

    # Use user-specified arguments instead of default arguments, if any.
    get_property(have_args TARGET ${name} PROPERTY _EP_${step}_ARGS SET)
    if(have_args)
      get_target_property(args ${name} _EP_${step}_ARGS)
    endif()

    list(APPEND cmd ${args})
  endif()

  set(${cmd_var} "${cmd}" PARENT_SCOPE)
endfunction()

function(_ep_write_log_script name step cmd_var)
  ExternalProject_Get_Property(${name} stamp_dir)
  set(command "${${cmd_var}}")

  set(make "")
  set(code_cygpath_make "")
  if("${command}" MATCHES "^\\$\\(MAKE\\)")
    # GNU make recognizes the string "$(MAKE)" as recursive make, so
    # ensure that it appears directly in the makefile.
    string(REGEX REPLACE "^\\$\\(MAKE\\)" "\${make}" command "${command}")
    set(make "-Dmake=$(MAKE)")

    if(WIN32 AND NOT CYGWIN)
      set(code_cygpath_make "
if(\${make} MATCHES \"^/\")
  execute_process(
    COMMAND cygpath -w \${make}
    OUTPUT_VARIABLE cygpath_make
    ERROR_VARIABLE cygpath_make
    RESULT_VARIABLE cygpath_error
    OUTPUT_STRIP_TRAILING_WHITESPACE
  )
  if(NOT cygpath_error)
    set(make \${cygpath_make})
  endif()
endif()
")
    endif()
  endif()

  set(config "")
  if("${CMAKE_CFG_INTDIR}" MATCHES "^\\$")
    string(REPLACE "${CMAKE_CFG_INTDIR}" "\${config}" command "${command}")
    set(config "-Dconfig=${CMAKE_CFG_INTDIR}")
  endif()

  # Wrap multiple 'COMMAND' lines up into a second-level wrapper
  # script so all output can be sent to one log file.
  if("${command}" MATCHES ";COMMAND;")
    set(code_execute_process "
${code_cygpath_make}
execute_process(COMMAND \${command} RESULT_VARIABLE result)
if(result)
  set(msg \"Command failed (\${result}):\\n\")
  foreach(arg IN LISTS command)
    set(msg \"\${msg} '\${arg}'\")
  endforeach()
  message(FATAL_ERROR \"\${msg}\")
endif()
")
    set(code "")
    set(cmd "")
    set(sep "")
    foreach(arg IN LISTS command)
      if("x${arg}" STREQUAL "xCOMMAND")
        set(code "${code}set(command \"${cmd}\")${code_execute_process}")
        set(cmd "")
        set(sep "")
      else()
        set(cmd "${cmd}${sep}${arg}")
        set(sep ";")
      endif()
    endforeach()
    set(code "${code}set(command \"${cmd}\")${code_execute_process}")
    file(WRITE ${stamp_dir}/${name}-${step}-impl.cmake "${code}")
    set(command ${CMAKE_COMMAND} "-Dmake=\${make}" "-Dconfig=\${config}" -P ${stamp_dir}/${name}-${step}-impl.cmake)
  endif()

  # Wrap the command in a script to log output to files.
  set(script ${stamp_dir}/${name}-${step}.cmake)
  set(logbase ${stamp_dir}/${name}-${step})
  file(WRITE ${script} "
${code_cygpath_make}
set(command \"${command}\")
execute_process(
  COMMAND \${command}
  RESULT_VARIABLE result
  OUTPUT_FILE \"${logbase}-out.log\"
  ERROR_FILE \"${logbase}-err.log\"
  )
if(result)
  set(msg \"Command failed: \${result}\\n\")
  foreach(arg IN LISTS command)
    set(msg \"\${msg} '\${arg}'\")
  endforeach()
  set(msg \"\${msg}\\nSee also\\n  ${logbase}-*.log\\n\")
  message(FATAL_ERROR \"\${msg}\")
else()
  set(msg \"${name} ${step} command succeeded.  See also ${logbase}-*.log\\n\")
  message(STATUS \"\${msg}\")
endif()
")
  set(command ${CMAKE_COMMAND} ${make} ${config} -P ${script})
  set(${cmd_var} "${command}" PARENT_SCOPE)
endfunction()

# This module used to use "/${CMAKE_CFG_INTDIR}" directly and produced
# makefiles with "/./" in paths for custom command dependencies. Which
# resulted in problems with parallel make -j invocations.
#
# This function was added so that the suffix (search below for ${cfgdir}) is
# only set to "/${CMAKE_CFG_INTDIR}" when ${CMAKE_CFG_INTDIR} is not going to
# be "." (multi-configuration build systems like Visual Studio and Xcode...)
#
function(_ep_get_configuration_subdir_suffix suffix_var)
  set(suffix "")
  if(CMAKE_CONFIGURATION_TYPES)
    set(suffix "/${CMAKE_CFG_INTDIR}")
  endif()
  set(${suffix_var} "${suffix}" PARENT_SCOPE)
endfunction()


function(_ep_get_step_stampfile name step stampfile_var)
  ExternalProject_Get_Property(${name} stamp_dir)

  _ep_get_configuration_subdir_suffix(cfgdir)
  set(stampfile "${stamp_dir}${cfgdir}/${name}-${step}")

  set(${stampfile_var} "${stampfile}" PARENT_SCOPE)
endfunction()


function(ExternalProject_Add_StepTargets name)
  set(steps ${ARGN})

  foreach(step ${steps})
    _ep_get_step_stampfile(${name} ${step} stamp_file)
    add_custom_target(${name}-${step}
      DEPENDS ${stamp_file})
    set_property(TARGET ${name}-${step} PROPERTY LABELS ${name})
    set_property(TARGET ${name}-${step} PROPERTY FOLDER "ExternalProjectTargets/${name}")

    # Depend on other external projects (target-level).
    get_property(deps TARGET ${name} PROPERTY _EP_DEPENDS)
    foreach(arg IN LISTS deps)
      add_dependencies(${name}-${step} ${arg})
    endforeach()
  endforeach()
endfunction()


function(ExternalProject_Add_Step name step)
  set(cmf_dir ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles)
  _ep_get_configuration_subdir_suffix(cfgdir)

  set(complete_stamp_file "${cmf_dir}${cfgdir}/${name}-complete")
  _ep_get_step_stampfile(${name} ${step} stamp_file)

  _ep_parse_arguments(ExternalProject_Add_Step
                      ${name} _EP_${step}_ "${ARGN}")

  get_property(exclude_from_main TARGET ${name} PROPERTY _EP_${step}_EXCLUDE_FROM_MAIN)
  if(NOT exclude_from_main)
    add_custom_command(APPEND
      OUTPUT ${complete_stamp_file}
      DEPENDS ${stamp_file}
      )
  endif()

  # Steps depending on this step.
  get_property(dependers TARGET ${name} PROPERTY _EP_${step}_DEPENDERS)
  foreach(depender IN LISTS dependers)
    _ep_get_step_stampfile(${name} ${depender} depender_stamp_file)
    add_custom_command(APPEND
      OUTPUT ${depender_stamp_file}
      DEPENDS ${stamp_file}
      )
  endforeach()

  # Dependencies on files.
  get_property(depends TARGET ${name} PROPERTY _EP_${step}_DEPENDS)

  # Dependencies on steps.
  get_property(dependees TARGET ${name} PROPERTY _EP_${step}_DEPENDEES)
  foreach(dependee IN LISTS dependees)
    _ep_get_step_stampfile(${name} ${dependee} dependee_stamp_file)
    list(APPEND depends ${dependee_stamp_file})
  endforeach()

  # The command to run.
  get_property(command TARGET ${name} PROPERTY _EP_${step}_COMMAND)
  if(command)
    set(comment "Performing ${step} step for '${name}'")
  else()
    set(comment "No ${step} step for '${name}'")
  endif()
  get_property(work_dir TARGET ${name} PROPERTY _EP_${step}_WORKING_DIRECTORY)

  # Replace list separators.
  get_property(sep TARGET ${name} PROPERTY _EP_LIST_SEPARATOR)
  if(sep AND command)
    string(REPLACE "${sep}" "\\;" command "${command}")
  endif()

  # Replace location tags.
  _ep_replace_location_tags(${name} comment command work_dir)

  # Custom comment?
  get_property(comment_set TARGET ${name} PROPERTY _EP_${step}_COMMENT SET)
  if(comment_set)
    get_property(comment TARGET ${name} PROPERTY _EP_${step}_COMMENT)
  endif()

  # Run every time?
  get_property(always TARGET ${name} PROPERTY _EP_${step}_ALWAYS)
  if(always)
    set_property(SOURCE ${stamp_file} PROPERTY SYMBOLIC 1)
    set(touch)
  else()
    set(touch ${CMAKE_COMMAND} -E touch ${stamp_file})
  endif()

  # Wrap with log script?
  get_property(log TARGET ${name} PROPERTY _EP_${step}_LOG)
  if(command AND log)
    _ep_write_log_script(${name} ${step} command)
  endif()

  add_custom_command(
    OUTPUT ${stamp_file}
    COMMENT ${comment}
    COMMAND ${command}
    COMMAND ${touch}
    DEPENDS ${depends}
    WORKING_DIRECTORY ${work_dir}
    VERBATIM
    )

  # Add custom "step target"?
  get_property(step_targets TARGET ${name} PROPERTY _EP_STEP_TARGETS)
  if(NOT step_targets)
    get_property(step_targets DIRECTORY PROPERTY EP_STEP_TARGETS)
  endif()
  foreach(st ${step_targets})
    if("${st}" STREQUAL "${step}")
      ExternalProject_Add_StepTargets(${name} ${step})
      break()
    endif()
  endforeach()
endfunction()


function(_ep_add_mkdir_command name)
  ExternalProject_Get_Property(${name}
    source_dir binary_dir install_dir stamp_dir download_dir tmp_dir)

  _ep_get_configuration_subdir_suffix(cfgdir)

  ExternalProject_Add_Step(${name} mkdir
    COMMENT "Creating directories for '${name}'"
    COMMAND ${CMAKE_COMMAND} -E make_directory ${source_dir}
    COMMAND ${CMAKE_COMMAND} -E make_directory ${binary_dir}
    COMMAND ${CMAKE_COMMAND} -E make_directory ${install_dir}
    COMMAND ${CMAKE_COMMAND} -E make_directory ${tmp_dir}
    COMMAND ${CMAKE_COMMAND} -E make_directory ${stamp_dir}${cfgdir}
    COMMAND ${CMAKE_COMMAND} -E make_directory ${download_dir}
    )
endfunction()


function(_ep_get_git_version git_EXECUTABLE git_version_var)
  if(git_EXECUTABLE)
    execute_process(
      COMMAND "${git_EXECUTABLE}" --version
      OUTPUT_VARIABLE ov
      ERROR_VARIABLE ev
      OUTPUT_STRIP_TRAILING_WHITESPACE
      )
    string(REGEX REPLACE "^git version (.+)$" "\\1" version "${ov}")
    set(${git_version_var} "${version}" PARENT_SCOPE)
  endif()
endfunction()


function(_ep_is_dir_empty dir empty_var)
  file(GLOB gr "${dir}/*")
  if("${gr}" STREQUAL "")
    set(${empty_var} 1 PARENT_SCOPE)
  else()
    set(${empty_var} 0 PARENT_SCOPE)
  endif()
endfunction()


function(_ep_add_download_command name)
  ExternalProject_Get_Property(${name} source_dir stamp_dir download_dir tmp_dir)

  get_property(cmd_set TARGET ${name} PROPERTY _EP_DOWNLOAD_COMMAND SET)
  get_property(cmd TARGET ${name} PROPERTY _EP_DOWNLOAD_COMMAND)
  get_property(cvs_repository TARGET ${name} PROPERTY _EP_CVS_REPOSITORY)
  get_property(svn_repository TARGET ${name} PROPERTY _EP_SVN_REPOSITORY)
  get_property(git_repository TARGET ${name} PROPERTY _EP_GIT_REPOSITORY)
  get_property(hg_repository  TARGET ${name} PROPERTY _EP_HG_REPOSITORY )
  get_property(url TARGET ${name} PROPERTY _EP_URL)
  get_property(fname TARGET ${name} PROPERTY _EP_DOWNLOAD_NAME)

  # TODO: Perhaps file:// should be copied to download dir before extraction.
  string(REGEX REPLACE "^file://" "" url "${url}")

  set(depends)
  set(comment)
  set(work_dir)

  if(cmd_set)
    set(work_dir ${download_dir})
  elseif(cvs_repository)
    find_package(CVS QUIET)
    if(NOT CVS_EXECUTABLE)
      message(FATAL_ERROR "error: could not find cvs for checkout of ${name}")
    endif()

    get_target_property(cvs_module ${name} _EP_CVS_MODULE)
    if(NOT cvs_module)
      message(FATAL_ERROR "error: no CVS_MODULE")
    endif()

    get_property(cvs_tag TARGET ${name} PROPERTY _EP_CVS_TAG)

    set(repository ${cvs_repository})
    set(module ${cvs_module})
    set(tag ${cvs_tag})
    configure_file(
      "${CMAKE_ROOT}/Modules/RepositoryInfo.txt.in"
      "${stamp_dir}/${name}-cvsinfo.txt"
      @ONLY
      )

    get_filename_component(src_name "${source_dir}" NAME)
    get_filename_component(work_dir "${source_dir}" PATH)
    set(comment "Performing download step (CVS checkout) for '${name}'")
    set(cmd ${CVS_EXECUTABLE} -d ${cvs_repository} -q co ${cvs_tag} -d ${src_name} ${cvs_module})
    list(APPEND depends ${stamp_dir}/${name}-cvsinfo.txt)
  elseif(svn_repository)
    find_package(Subversion QUIET)
    if(NOT Subversion_SVN_EXECUTABLE)
      message(FATAL_ERROR "error: could not find svn for checkout of ${name}")
    endif()

    get_property(svn_revision TARGET ${name} PROPERTY _EP_SVN_REVISION)
    get_property(svn_username TARGET ${name} PROPERTY _EP_SVN_USERNAME)
    get_property(svn_password TARGET ${name} PROPERTY _EP_SVN_PASSWORD)
    get_property(svn_trust_cert TARGET ${name} PROPERTY _EP_SVN_TRUST_CERT)

    set(repository "${svn_repository} user=${svn_username} password=${svn_password}")
    set(module)
    set(tag ${svn_revision})
    configure_file(
      "${CMAKE_ROOT}/Modules/RepositoryInfo.txt.in"
      "${stamp_dir}/${name}-svninfo.txt"
      @ONLY
      )

    get_filename_component(src_name "${source_dir}" NAME)
    get_filename_component(work_dir "${source_dir}" PATH)
    set(comment "Performing download step (SVN checkout) for '${name}'")
    set(svn_user_pw_args "")
    if(DEFINED svn_username)
      set(svn_user_pw_args ${svn_user_pw_args} "--username=${svn_username}")
    endif()
    if(DEFINED svn_password)
      set(svn_user_pw_args ${svn_user_pw_args} "--password=${svn_password}")
    endif()
    if(svn_trust_cert)
      set(svn_trust_cert_args --trust-server-cert)
    endif()
    set(cmd ${Subversion_SVN_EXECUTABLE} co ${svn_repository} ${svn_revision}
      --non-interactive ${svn_trust_cert_args} ${svn_user_pw_args} ${src_name})
    list(APPEND depends ${stamp_dir}/${name}-svninfo.txt)
  elseif(git_repository)
    find_package(Git QUIET)
    if(NOT GIT_EXECUTABLE)
      message(FATAL_ERROR "error: could not find git for clone of ${name}")
    endif()

    # The git submodule update '--recursive' flag requires git >= v1.6.5
    #
    _ep_get_git_version("${GIT_EXECUTABLE}" git_version)
    if(git_version VERSION_LESS 1.6.5)
      message(FATAL_ERROR "error: git version 1.6.5 or later required for 'git submodule update --recursive': git_version='${git_version}'")
    endif()

    get_property(git_tag TARGET ${name} PROPERTY _EP_GIT_TAG)
    if(NOT git_tag)
      set(git_tag "master")
    endif()
    get_property(git_submodules TARGET ${name} PROPERTY _EP_GIT_SUBMODULES)

    # For the download step, and the git clone operation, only the repository
    # should be recorded in a configured RepositoryInfo file. If the repo
    # changes, the clone script should be run again. But if only the tag
    # changes, avoid running the clone script again. Let the 'always' running
    # update step checkout the new tag.
    #
    set(repository ${git_repository})
    set(module)
    set(tag)
    configure_file(
      "${CMAKE_ROOT}/Modules/RepositoryInfo.txt.in"
      "${stamp_dir}/${name}-gitinfo.txt"
      @ONLY
      )

    get_filename_component(src_name "${source_dir}" NAME)
    get_filename_component(work_dir "${source_dir}" PATH)

    # Since git clone doesn't succeed if the non-empty source_dir exists,
    # create a cmake script to invoke as download command.
    # The script will delete the source directory and then call git clone.
    #
    _ep_write_gitclone_script(${tmp_dir}/${name}-gitclone.cmake ${source_dir}
      ${GIT_EXECUTABLE} ${git_repository} ${git_tag} "${git_submodules}" ${src_name} ${work_dir}
      ${stamp_dir}/${name}-gitinfo.txt ${stamp_dir}/${name}-gitclone-lastrun.txt
      )
    set(comment "Performing download step (git clone) for '${name}'")
    set(cmd ${CMAKE_COMMAND} -P ${tmp_dir}/${name}-gitclone.cmake)
    list(APPEND depends ${stamp_dir}/${name}-gitinfo.txt)
  elseif(hg_repository)
    find_package(Hg QUIET)
    if(NOT HG_EXECUTABLE)
      message(FATAL_ERROR "error: could not find hg for clone of ${name}")
    endif()

    get_property(hg_tag TARGET ${name} PROPERTY _EP_HG_TAG)
    if(NOT hg_tag)
      set(hg_tag "tip")
    endif()

    # For the download step, and the hg clone operation, only the repository
    # should be recorded in a configured RepositoryInfo file. If the repo
    # changes, the clone script should be run again. But if only the tag
    # changes, avoid running the clone script again. Let the 'always' running
    # update step checkout the new tag.
    #
    set(repository ${hg_repository})
    set(module)
    set(tag)
    configure_file(
      "${CMAKE_ROOT}/Modules/RepositoryInfo.txt.in"
      "${stamp_dir}/${name}-hginfo.txt"
      @ONLY
      )

    get_filename_component(src_name "${source_dir}" NAME)
    get_filename_component(work_dir "${source_dir}" PATH)

    # Since hg clone doesn't succeed if the non-empty source_dir exists,
    # create a cmake script to invoke as download command.
    # The script will delete the source directory and then call hg clone.
    #
    _ep_write_hgclone_script(${tmp_dir}/${name}-hgclone.cmake ${source_dir}
      ${HG_EXECUTABLE} ${hg_repository} ${hg_tag} ${src_name} ${work_dir}
      ${stamp_dir}/${name}-hginfo.txt ${stamp_dir}/${name}-hgclone-lastrun.txt
      )
    set(comment "Performing download step (hg clone) for '${name}'")
    set(cmd ${CMAKE_COMMAND} -P ${tmp_dir}/${name}-hgclone.cmake)
    list(APPEND depends ${stamp_dir}/${name}-hginfo.txt)
  elseif(url)
    get_filename_component(work_dir "${source_dir}" PATH)
    get_property(hash TARGET ${name} PROPERTY _EP_URL_HASH)
    if(hash AND NOT "${hash}" MATCHES "${_ep_hash_regex}")
      message(FATAL_ERROR "URL_HASH is set to\n  ${hash}\n"
        "but must be ALGO=value where ALGO is\n  ${_ep_hash_algos}\n"
        "and value is a hex string.")
    endif()
    get_property(md5 TARGET ${name} PROPERTY _EP_URL_MD5)
    if(md5 AND NOT "MD5=${md5}" MATCHES "${_ep_hash_regex}")
      message(FATAL_ERROR "URL_MD5 is set to\n  ${md5}\nbut must be a hex string.")
    endif()
    if(md5 AND NOT hash)
      set(hash "MD5=${md5}")
    endif()
    set(repository "external project URL")
    set(module "${url}")
    set(tag "${hash}")
    set(retries 0)
    set(download_script "")
    configure_file(
      "${CMAKE_ROOT}/Modules/RepositoryInfo.txt.in"
      "${stamp_dir}/${name}-urlinfo.txt"
      @ONLY
      )
    list(APPEND depends ${stamp_dir}/${name}-urlinfo.txt)
    if(IS_DIRECTORY "${url}")
      get_filename_component(abs_dir "${url}" ABSOLUTE)
      set(comment "Performing download step (DIR copy) for '${name}'")
      set(cmd   ${CMAKE_COMMAND} -E remove_directory ${source_dir}
        COMMAND ${CMAKE_COMMAND} -E copy_directory ${abs_dir} ${source_dir})
    else()
      if("${url}" MATCHES "^[a-z]+://")
        # TODO: Should download and extraction be different steps?
        if("x${fname}" STREQUAL "x")
          string(REGEX MATCH "[^/\\?]*$" fname "${url}")
        endif()
        if(NOT "${fname}" MATCHES "(\\.|=)(7z|tar|tar\\.bz2|tar\\.gz|tar\\.xz|tbz2|tgz|txz|zip)$")
          string(REGEX MATCH "([^/\\?]+(\\.|=)(7z|tar|tar\\.bz2|tar\\.gz|tar\\.xz|tbz2|tgz|txz|zip))/.*$" match_result "${url}")
          set(fname "${CMAKE_MATCH_1}")
        endif()
        if(NOT "${fname}" MATCHES "(\\.|=)(7z|tar|tar\\.bz2|tar\\.gz|tar\\.xz|tbz2|tgz|txz|zip)$")
          message(FATAL_ERROR "Could not extract tarball filename from url:\n  ${url}")
        endif()
        string(REPLACE ";" "-" fname "${fname}")
        set(file ${download_dir}/${fname})
        get_property(timeout TARGET ${name} PROPERTY _EP_TIMEOUT)
        get_property(no_progress TARGET ${name} PROPERTY _EP_DOWNLOAD_NO_PROGRESS)
        get_property(tls_verify TARGET ${name} PROPERTY _EP_TLS_VERIFY)
        get_property(tls_cainfo TARGET ${name} PROPERTY _EP_TLS_CAINFO)
        set(download_script "${stamp_dir}/download-${name}.cmake")
        _ep_write_downloadfile_script("${download_script}" "${url}" "${file}" "${timeout}" "${no_progress}" "${hash}" "${tls_verify}" "${tls_cainfo}")
        set(cmd ${CMAKE_COMMAND} -P "${download_script}"
          COMMAND)
        set(retries 3)
        set(comment "Performing download step (download, verify and extract) for '${name}'")
      else()
        set(file "${url}")
        set(comment "Performing download step (verify and extract) for '${name}'")
      endif()
      _ep_write_verifyfile_script("${stamp_dir}/verify-${name}.cmake" "${file}" "${hash}" "${retries}" "${download_script}")
      list(APPEND cmd ${CMAKE_COMMAND} -P ${stamp_dir}/verify-${name}.cmake
        COMMAND)
      _ep_write_extractfile_script("${stamp_dir}/extract-${name}.cmake" "${name}" "${file}" "${source_dir}")
      list(APPEND cmd ${CMAKE_COMMAND} -P ${stamp_dir}/extract-${name}.cmake)
    endif()
  else()
    _ep_is_dir_empty("${source_dir}" empty)
    if(${empty})
      message(SEND_ERROR "error: no download info for '${name}' -- please specify existing/non-empty SOURCE_DIR or one of URL, CVS_REPOSITORY and CVS_MODULE, SVN_REPOSITORY, GIT_REPOSITORY, HG_REPOSITORY or DOWNLOAD_COMMAND")
    endif()
  endif()

  get_property(log TARGET ${name} PROPERTY _EP_LOG_DOWNLOAD)
  if(log)
    set(log LOG 1)
  else()
    set(log "")
  endif()

  ExternalProject_Add_Step(${name} download
    COMMENT ${comment}
    COMMAND ${cmd}
    WORKING_DIRECTORY ${work_dir}
    DEPENDS ${depends}
    DEPENDEES mkdir
    ${log}
    )
endfunction()


function(_ep_add_update_command name)
  ExternalProject_Get_Property(${name} source_dir tmp_dir)

  get_property(cmd_set TARGET ${name} PROPERTY _EP_UPDATE_COMMAND SET)
  get_property(cmd TARGET ${name} PROPERTY _EP_UPDATE_COMMAND)
  get_property(cvs_repository TARGET ${name} PROPERTY _EP_CVS_REPOSITORY)
  get_property(svn_repository TARGET ${name} PROPERTY _EP_SVN_REPOSITORY)
  get_property(git_repository TARGET ${name} PROPERTY _EP_GIT_REPOSITORY)
  get_property(hg_repository  TARGET ${name} PROPERTY _EP_HG_REPOSITORY )

  set(work_dir)
  set(comment)
  set(always)

  if(cmd_set)
    set(work_dir ${source_dir})
  elseif(cvs_repository)
    if(NOT CVS_EXECUTABLE)
      message(FATAL_ERROR "error: could not find cvs for update of ${name}")
    endif()
    set(work_dir ${source_dir})
    set(comment "Performing update step (CVS update) for '${name}'")
    get_property(cvs_tag TARGET ${name} PROPERTY _EP_CVS_TAG)
    set(cmd ${CVS_EXECUTABLE} -d ${cvs_repository} -q up -dP ${cvs_tag})
    set(always 1)
  elseif(svn_repository)
    if(NOT Subversion_SVN_EXECUTABLE)
      message(FATAL_ERROR "error: could not find svn for update of ${name}")
    endif()
    set(work_dir ${source_dir})
    set(comment "Performing update step (SVN update) for '${name}'")
    get_property(svn_revision TARGET ${name} PROPERTY _EP_SVN_REVISION)
    get_property(svn_username TARGET ${name} PROPERTY _EP_SVN_USERNAME)
    get_property(svn_password TARGET ${name} PROPERTY _EP_SVN_PASSWORD)
    get_property(svn_trust_cert TARGET ${name} PROPERTY _EP_SVN_TRUST_CERT)
    set(svn_user_pw_args "")
    if(DEFINED svn_username)
      set(svn_user_pw_args ${svn_user_pw_args} "--username=${svn_username}")
    endif()
    if(DEFINED svn_password)
      set(svn_user_pw_args ${svn_user_pw_args} "--password=${svn_password}")
    endif()
    if(svn_trust_cert)
      set(svn_trust_cert_args --trust-server-cert)
    endif()
    set(cmd ${Subversion_SVN_EXECUTABLE} up ${svn_revision}
      --non-interactive ${svn_trust_cert_args} ${svn_user_pw_args})
    set(always 1)
  elseif(git_repository)
    if(NOT GIT_EXECUTABLE)
      message(FATAL_ERROR "error: could not find git for fetch of ${name}")
    endif()
    set(work_dir ${source_dir})
    set(comment "Performing update step for '${name}'")
    get_property(git_tag TARGET ${name} PROPERTY _EP_GIT_TAG)
    if(NOT git_tag)
      set(git_tag "master")
    endif()
    get_property(git_submodules TARGET ${name} PROPERTY _EP_GIT_SUBMODULES)
    _ep_write_gitupdate_script(${tmp_dir}/${name}-gitupdate.cmake
      ${GIT_EXECUTABLE} ${git_tag} "${git_submodules}" ${git_repository} ${work_dir}
      )
    set(cmd ${CMAKE_COMMAND} -P ${tmp_dir}/${name}-gitupdate.cmake)
    set(always 1)
  elseif(hg_repository)
    if(NOT HG_EXECUTABLE)
      message(FATAL_ERROR "error: could not find hg for pull of ${name}")
    endif()
    set(work_dir ${source_dir})
    set(comment "Performing update step (hg pull) for '${name}'")
    get_property(hg_tag TARGET ${name} PROPERTY _EP_HG_TAG)
    if(NOT hg_tag)
      set(hg_tag "tip")
    endif()
    if("${HG_VERSION_STRING}" STREQUAL "2.1")
      message(WARNING "Mercurial 2.1 does not distinguish an empty pull from a failed pull:
 http://mercurial.selenic.com/wiki/UpgradeNotes#A2.1.1:_revert_pull_return_code_change.2C_compile_issue_on_OS_X
 http://thread.gmane.org/gmane.comp.version-control.mercurial.devel/47656
Update to Mercurial >= 2.1.1.
")
    endif()
    set(cmd ${HG_EXECUTABLE} pull
      COMMAND ${HG_EXECUTABLE} update ${hg_tag}
      )
    set(always 1)
  endif()

  get_property(log TARGET ${name} PROPERTY _EP_LOG_UPDATE)
  if(log)
    set(log LOG 1)
  else()
    set(log "")
  endif()

  ExternalProject_Add_Step(${name} update
    COMMENT ${comment}
    COMMAND ${cmd}
    ALWAYS ${always}
    WORKING_DIRECTORY ${work_dir}
    DEPENDEES download
    ${log}
    )
endfunction()


function(_ep_add_patch_command name)
  ExternalProject_Get_Property(${name} source_dir)

  get_property(cmd_set TARGET ${name} PROPERTY _EP_PATCH_COMMAND SET)
  get_property(cmd TARGET ${name} PROPERTY _EP_PATCH_COMMAND)

  set(work_dir)

  if(cmd_set)
    set(work_dir ${source_dir})
  endif()

  ExternalProject_Add_Step(${name} patch
    COMMAND ${cmd}
    WORKING_DIRECTORY ${work_dir}
    DEPENDEES download
    )
endfunction()


# TODO: Make sure external projects use the proper compiler
function(_ep_add_configure_command name)
  ExternalProject_Get_Property(${name} source_dir binary_dir tmp_dir)

  # Depend on other external projects (file-level).
  set(file_deps)
  get_property(deps TARGET ${name} PROPERTY _EP_DEPENDS)
  foreach(dep IN LISTS deps)
    get_property(is_ep TARGET ${dep} PROPERTY _EP_IS_EXTERNAL_PROJECT)
    if(is_ep)
      _ep_get_step_stampfile(${dep} "done" done_stamp_file)
      list(APPEND file_deps ${done_stamp_file})
    endif()
  endforeach()

  get_property(cmd_set TARGET ${name} PROPERTY _EP_CONFIGURE_COMMAND SET)
  if(cmd_set)
    get_property(cmd TARGET ${name} PROPERTY _EP_CONFIGURE_COMMAND)
  else()
    get_target_property(cmake_command ${name} _EP_CMAKE_COMMAND)
    if(cmake_command)
      set(cmd "${cmake_command}")
    else()
      set(cmd "${CMAKE_COMMAND}")
    endif()

    get_property(cmake_args TARGET ${name} PROPERTY _EP_CMAKE_ARGS)
    list(APPEND cmd ${cmake_args})

    # If there are any CMAKE_CACHE_ARGS, write an initial cache and use it
    get_property(cmake_cache_args TARGET ${name} PROPERTY _EP_CMAKE_CACHE_ARGS)
    if(cmake_cache_args)
      set(_ep_cache_args_script "${tmp_dir}/${name}-cache.cmake")
      _ep_write_initial_cache(${name} "${_ep_cache_args_script}" "${cmake_cache_args}")
      list(APPEND cmd "-C${_ep_cache_args_script}")
    endif()

    get_target_property(cmake_generator ${name} _EP_CMAKE_GENERATOR)
    get_target_property(cmake_generator_platform ${name} _EP_CMAKE_GENERATOR_PLATFORM)
    get_target_property(cmake_generator_toolset ${name} _EP_CMAKE_GENERATOR_TOOLSET)
    if(cmake_generator)
      list(APPEND cmd "-G${cmake_generator}")
      if(cmake_generator_platform)
        list(APPEND cmd "-A${cmake_generator_platform}")
      endif()
      if(cmake_generator_toolset)
        list(APPEND cmd "-T${cmake_generator_toolset}")
      endif()
    else()
      if(CMAKE_EXTRA_GENERATOR)
        list(APPEND cmd "-G${CMAKE_EXTRA_GENERATOR} - ${CMAKE_GENERATOR}")
      else()
        list(APPEND cmd "-G${CMAKE_GENERATOR}")
      endif()
      if(cmake_generator_platform)
        message(FATAL_ERROR "Option CMAKE_GENERATOR_PLATFORM not allowed without CMAKE_GENERATOR.")
      endif()
      if(CMAKE_GENERATOR_PLATFORM)
        list(APPEND cmd "-A${CMAKE_GENERATOR_PLATFORM}")
      endif()
      if(cmake_generator_toolset)
        message(FATAL_ERROR "Option CMAKE_GENERATOR_TOOLSET not allowed without CMAKE_GENERATOR.")
      endif()
      if(CMAKE_GENERATOR_TOOLSET)
        list(APPEND cmd "-T${CMAKE_GENERATOR_TOOLSET}")
      endif()
    endif()

    list(APPEND cmd "${source_dir}")
  endif()

  # If anything about the configure command changes, (command itself, cmake
  # used, cmake args or cmake generator) then re-run the configure step.
  # Fixes issue http://public.kitware.com/Bug/view.php?id=10258
  #
  if(NOT EXISTS ${tmp_dir}/${name}-cfgcmd.txt.in)
    file(WRITE ${tmp_dir}/${name}-cfgcmd.txt.in "cmd='\@cmd\@'\n")
  endif()
  configure_file(${tmp_dir}/${name}-cfgcmd.txt.in ${tmp_dir}/${name}-cfgcmd.txt)
  list(APPEND file_deps ${tmp_dir}/${name}-cfgcmd.txt)
  list(APPEND file_deps ${_ep_cache_args_script})

  get_property(log TARGET ${name} PROPERTY _EP_LOG_CONFIGURE)
  if(log)
    set(log LOG 1)
  else()
    set(log "")
  endif()

  ExternalProject_Add_Step(${name} configure
    COMMAND ${cmd}
    WORKING_DIRECTORY ${binary_dir}
    DEPENDEES update patch
    DEPENDS ${file_deps}
    ${log}
    )
endfunction()


function(_ep_add_build_command name)
  ExternalProject_Get_Property(${name} binary_dir)

  get_property(cmd_set TARGET ${name} PROPERTY _EP_BUILD_COMMAND SET)
  if(cmd_set)
    get_property(cmd TARGET ${name} PROPERTY _EP_BUILD_COMMAND)
  else()
    _ep_get_build_command(${name} BUILD cmd)
  endif()

  get_property(log TARGET ${name} PROPERTY _EP_LOG_BUILD)
  if(log)
    set(log LOG 1)
  else()
    set(log "")
  endif()

  get_property(build_always TARGET ${name} PROPERTY _EP_BUILD_ALWAYS)
  if(build_always)
    set(always 1)
  else()
    set(always 0)
  endif()

  ExternalProject_Add_Step(${name} build
    COMMAND ${cmd}
    WORKING_DIRECTORY ${binary_dir}
    DEPENDEES configure
    ALWAYS ${always}
    ${log}
    )
endfunction()


function(_ep_add_install_command name)
  ExternalProject_Get_Property(${name} binary_dir)

  get_property(cmd_set TARGET ${name} PROPERTY _EP_INSTALL_COMMAND SET)
  if(cmd_set)
    get_property(cmd TARGET ${name} PROPERTY _EP_INSTALL_COMMAND)
  else()
    _ep_get_build_command(${name} INSTALL cmd)
  endif()

  get_property(log TARGET ${name} PROPERTY _EP_LOG_INSTALL)
  if(log)
    set(log LOG 1)
  else()
    set(log "")
  endif()

  ExternalProject_Add_Step(${name} install
    COMMAND ${cmd}
    WORKING_DIRECTORY ${binary_dir}
    DEPENDEES build
    ${log}
    )
endfunction()


function(_ep_add_test_command name)
  ExternalProject_Get_Property(${name} binary_dir)

  get_property(before TARGET ${name} PROPERTY _EP_TEST_BEFORE_INSTALL)
  get_property(after TARGET ${name} PROPERTY _EP_TEST_AFTER_INSTALL)
  get_property(cmd_set TARGET ${name} PROPERTY _EP_TEST_COMMAND SET)

  # Only actually add the test step if one of the test related properties is
  # explicitly set. (i.e. the test step is omitted unless requested...)
  #
  if(cmd_set OR before OR after)
    if(cmd_set)
      get_property(cmd TARGET ${name} PROPERTY _EP_TEST_COMMAND)
    else()
      _ep_get_build_command(${name} TEST cmd)
    endif()

    if(before)
      set(dep_args DEPENDEES build DEPENDERS install)
    else()
      set(dep_args DEPENDEES install)
    endif()

    get_property(log TARGET ${name} PROPERTY _EP_LOG_TEST)
    if(log)
      set(log LOG 1)
    else()
      set(log "")
    endif()

    ExternalProject_Add_Step(${name} test
      COMMAND ${cmd}
      WORKING_DIRECTORY ${binary_dir}
      ${dep_args}
      ${log}
      )
  endif()
endfunction()


function(ExternalProject_Add name)
  _ep_get_configuration_subdir_suffix(cfgdir)

  # Add a custom target for the external project.
  set(cmf_dir ${CMAKE_CURRENT_BINARY_DIR}/CMakeFiles)
  set(complete_stamp_file "${cmf_dir}${cfgdir}/${name}-complete")

  # The "ALL" option to add_custom_target just tells it to not set the
  # EXCLUDE_FROM_ALL target property. Later, if the EXCLUDE_FROM_ALL
  # argument was passed, we explicitly set it for the target.
  add_custom_target(${name} ALL DEPENDS ${complete_stamp_file})
  set_property(TARGET ${name} PROPERTY _EP_IS_EXTERNAL_PROJECT 1)
  set_property(TARGET ${name} PROPERTY LABELS ${name})
  set_property(TARGET ${name} PROPERTY FOLDER "ExternalProjectTargets/${name}")

  _ep_parse_arguments(ExternalProject_Add ${name} _EP_ "${ARGN}")
  _ep_set_directories(${name})
  _ep_get_step_stampfile(${name} "done" done_stamp_file)
  _ep_get_step_stampfile(${name} "install" install_stamp_file)

  # Set the EXCLUDE_FROM_ALL target property if required.
  get_property(exclude_from_all TARGET ${name} PROPERTY _EP_EXCLUDE_FROM_ALL)
  if(exclude_from_all)
    set_property(TARGET ${name} PROPERTY EXCLUDE_FROM_ALL TRUE)
  endif()

  # The 'complete' step depends on all other steps and creates a
  # 'done' mark.  A dependent external project's 'configure' step
  # depends on the 'done' mark so that it rebuilds when this project
  # rebuilds.  It is important that 'done' is not the output of any
  # custom command so that CMake does not propagate build rules to
  # other external project targets, which may cause problems during
  # parallel builds.  However, the Ninja generator needs to see the entire
  # dependency graph, and can cope with custom commands belonging to
  # multiple targets, so we add the 'done' mark as an output for Ninja only.
  set(complete_outputs ${complete_stamp_file})
  if(${CMAKE_GENERATOR} MATCHES "Ninja")
    set(complete_outputs ${complete_outputs} ${done_stamp_file})
  endif()

  add_custom_command(
    OUTPUT ${complete_outputs}
    COMMENT "Completed '${name}'"
    COMMAND ${CMAKE_COMMAND} -E make_directory ${cmf_dir}${cfgdir}
    COMMAND ${CMAKE_COMMAND} -E touch ${complete_stamp_file}
    COMMAND ${CMAKE_COMMAND} -E touch ${done_stamp_file}
    DEPENDS ${install_stamp_file}
    VERBATIM
    )


  # Depend on other external projects (target-level).
  get_property(deps TARGET ${name} PROPERTY _EP_DEPENDS)
  foreach(arg IN LISTS deps)
    add_dependencies(${name} ${arg})
  endforeach()

  # Set up custom build steps based on the target properties.
  # Each step depends on the previous one.
  #
  # The target depends on the output of the final step.
  # (Already set up above in the DEPENDS of the add_custom_target command.)
  #
  _ep_add_mkdir_command(${name})
  _ep_add_download_command(${name})
  _ep_add_update_command(${name})
  _ep_add_patch_command(${name})
  _ep_add_configure_command(${name})
  _ep_add_build_command(${name})
  _ep_add_install_command(${name})

  # Test is special in that it might depend on build, or it might depend
  # on install.
  #
  _ep_add_test_command(${name})
endfunction()