Skip to content
Navigation Menu
{{ message }}
forked from netdata/netdata
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathemitter.py
More file actions
1141 lines (1024 loc) · 42.3 KB
/
Copy pathemitter.py
File metadata and controls
1141 lines (1024 loc) · 42.3 KB
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
# SPDX-License-Identifier: MIT
# Emitter expects events obeying the following grammar:
# stream ::= STREAM-START document* STREAM-END
# document ::= DOCUMENT-START node DOCUMENT-END
# node ::= SCALAR | sequence | mapping
# sequence ::= SEQUENCE-START node* SEQUENCE-END
# mapping ::= MAPPING-START (node node)* MAPPING-END
__all__ = ['Emitter', 'EmitterError']
from error import YAMLError
from events import *
class EmitterError(YAMLError):
pass
class ScalarAnalysis(object):
def __init__(self, scalar, empty, multiline,
allow_flow_plain, allow_block_plain,
allow_single_quoted, allow_double_quoted,
allow_block):
self.scalar = scalar
self.empty = empty
self.multiline = multiline
self.allow_flow_plain = allow_flow_plain
self.allow_block_plain = allow_block_plain
self.allow_single_quoted = allow_single_quoted
self.allow_double_quoted = allow_double_quoted
self.allow_block = allow_block
class Emitter(object):
DEFAULT_TAG_PREFIXES = {
u'!' : u'!',
u'tag:yaml.org,2002:' : u'!!',
}
def __init__(self, stream, canonical=None, indent=None, width=None,
allow_unicode=None, line_break=None):
# The stream should have the methods `write` and possibly `flush`.
self.stream = stream
# Encoding can be overriden by STREAM-START.
self.encoding = None
# Emitter is a state machine with a stack of states to handle nested
# structures.
self.states = []
self.state = self.expect_stream_start
# Current event and the event queue.
self.events = []
self.event = None
# The current indentation level and the stack of previous indents.
self.indents = []
self.indent = None
# Flow level.
self.flow_level = 0
# Contexts.
self.root_context = False
self.sequence_context = False
self.mapping_context = False
self.simple_key_context = False
# Characteristics of the last emitted character:
# - current position.
# - is it a whitespace?
# - is it an indention character
# (indentation space, '-', '?', or ':')?
self.line = 0
self.column = 0
self.whitespace = True
self.indention = True
# Whether the document requires an explicit document indicator
self.open_ended = False
# Formatting details.
self.canonical = canonical
self.allow_unicode = allow_unicode
self.best_indent = 2
if indent and 1 < indent < 10:
self.best_indent = indent
self.best_width = 80
if width and width > self.best_indent*2:
self.best_width = width
self.best_line_break = u'\n'
if line_break in [u'\r', u'\n', u'\r\n']:
self.best_line_break = line_break
# Tag prefixes.
self.tag_prefixes = None
# Prepared anchor and tag.
self.prepared_anchor = None
self.prepared_tag = None
# Scalar analysis and style.
self.analysis = None
self.style = None
def dispose(self):
# Reset the state attributes (to clear self-references)
self.states = []
self.state = None
def emit(self, event):
self.events.append(event)
while not self.need_more_events():
self.event = self.events.pop(0)
self.state()
self.event = None
# In some cases, we wait for a few next events before emitting.
def need_more_events(self):
if not self.events:
return True
event = self.events[0]
if isinstance(event, DocumentStartEvent):
return self.need_events(1)
elif isinstance(event, SequenceStartEvent):
return self.need_events(2)
elif isinstance(event, MappingStartEvent):
return self.need_events(3)
else:
return False
def need_events(self, count):
level = 0
for event in self.events[1:]:
if isinstance(event, (DocumentStartEvent, CollectionStartEvent)):
level += 1
elif isinstance(event, (DocumentEndEvent, CollectionEndEvent)):
level -= 1
elif isinstance(event, StreamEndEvent):
level = -1
if level < 0:
return False
return (len(self.events) < count+1)
def increase_indent(self, flow=False, indentless=False):
self.indents.append(self.indent)
if self.indent is None:
if flow:
self.indent = self.best_indent
else:
self.indent = 0
elif not indentless:
self.indent += self.best_indent
# States.
# Stream handlers.
def expect_stream_start(self):
if isinstance(self.event, StreamStartEvent):
if self.event.encoding and not getattr(self.stream, 'encoding', None):
self.encoding = self.event.encoding
self.write_stream_start()
self.state = self.expect_first_document_start
else:
raise EmitterError("expected StreamStartEvent, but got %s"
% self.event)
def expect_nothing(self):
raise EmitterError("expected nothing, but got %s" % self.event)
# Document handlers.
def expect_first_document_start(self):
return self.expect_document_start(first=True)
def expect_document_start(self, first=False):
if isinstance(self.event, DocumentStartEvent):
if (self.event.version or self.event.tags) and self.open_ended:
self.write_indicator(u'...', True)
self.write_indent()
if self.event.version:
version_text = self.prepare_version(self.event.version)
self.write_version_directive(version_text)
self.tag_prefixes = self.DEFAULT_TAG_PREFIXES.copy()
if self.event.tags:
handles = self.event.tags.keys()
handles.sort()
for handle in handles:
prefix = self.event.tags[handle]
self.tag_prefixes[prefix] = handle
handle_text = self.prepare_tag_handle(handle)
prefix_text = self.prepare_tag_prefix(prefix)
self.write_tag_directive(handle_text, prefix_text)
implicit = (first and not self.event.explicit and not self.canonical
and not self.event.version and not self.event.tags
and not self.check_empty_document())
if not implicit:
self.write_indent()
self.write_indicator(u'---', True)
if self.canonical:
self.write_indent()
self.state = self.expect_document_root
elif isinstance(self.event, StreamEndEvent):
if self.open_ended:
self.write_indicator(u'...', True)
self.write_indent()
self.write_stream_end()
self.state = self.expect_nothing
else:
raise EmitterError("expected DocumentStartEvent, but got %s"
% self.event)
def expect_document_end(self):
if isinstance(self.event, DocumentEndEvent):
self.write_indent()
if self.event.explicit:
self.write_indicator(u'...', True)
self.write_indent()
self.flush_stream()
self.state = self.expect_document_start
else:
raise EmitterError("expected DocumentEndEvent, but got %s"
% self.event)
def expect_document_root(self):
self.states.append(self.expect_document_end)
self.expect_node(root=True)
# Node handlers.
def expect_node(self, root=False, sequence=False, mapping=False,
simple_key=False):
self.root_context = root
self.sequence_context = sequence
self.mapping_context = mapping
self.simple_key_context = simple_key
if isinstance(self.event, AliasEvent):
self.expect_alias()
elif isinstance(self.event, (ScalarEvent, CollectionStartEvent)):
self.process_anchor(u'&')
self.process_tag()
if isinstance(self.event, ScalarEvent):
self.expect_scalar()
elif isinstance(self.event, SequenceStartEvent):
if self.flow_level or self.canonical or self.event.flow_style \
or self.check_empty_sequence():
self.expect_flow_sequence()
else:
self.expect_block_sequence()
elif isinstance(self.event, MappingStartEvent):
if self.flow_level or self.canonical or self.event.flow_style \
or self.check_empty_mapping():
self.expect_flow_mapping()
else:
self.expect_block_mapping()
else:
raise EmitterError("expected NodeEvent, but got %s" % self.event)
def expect_alias(self):
if self.event.anchor is None:
raise EmitterError("anchor is not specified for alias")
self.process_anchor(u'*')
self.state = self.states.pop()
def expect_scalar(self):
self.increase_indent(flow=True)
self.process_scalar()
self.indent = self.indents.pop()
self.state = self.states.pop()
# Flow sequence handlers.
def expect_flow_sequence(self):
self.write_indicator(u'[', True, whitespace=True)
self.flow_level += 1
self.increase_indent(flow=True)
self.state = self.expect_first_flow_sequence_item
def expect_first_flow_sequence_item(self):
if isinstance(self.event, SequenceEndEvent):
self.indent = self.indents.pop()
self.flow_level -= 1
self.write_indicator(u']', False)
self.state = self.states.pop()
else:
if self.canonical or self.column > self.best_width:
self.write_indent()
self.states.append(self.expect_flow_sequence_item)
self.expect_node(sequence=True)
def expect_flow_sequence_item(self):
if isinstance(self.event, SequenceEndEvent):
self.indent = self.indents.pop()
self.flow_level -= 1
if self.canonical:
self.write_indicator(u',', False)
self.write_indent()
self.write_indicator(u']', False)
self.state = self.states.pop()
else:
self.write_indicator(u',', False)
if self.canonical or self.column > self.best_width:
self.write_indent()
self.states.append(self.expect_flow_sequence_item)
self.expect_node(sequence=True)
# Flow mapping handlers.
def expect_flow_mapping(self):
self.write_indicator(u'{', True, whitespace=True)
self.flow_level += 1
self.increase_indent(flow=True)
self.state = self.expect_first_flow_mapping_key
def expect_first_flow_mapping_key(self):
if isinstance(self.event, MappingEndEvent):
self.indent = self.indents.pop()
self.flow_level -= 1
self.write_indicator(u'}', False)
self.state = self.states.pop()
else:
if self.canonical or self.column > self.best_width:
self.write_indent()
if not self.canonical and self.check_simple_key():
self.states.append(self.expect_flow_mapping_simple_value)
self.expect_node(mapping=True, simple_key=True)
else:
self.write_indicator(u'?', True)
self.states.append(self.expect_flow_mapping_value)
self.expect_node(mapping=True)
def expect_flow_mapping_key(self):
if isinstance(self.event, MappingEndEvent):
self.indent = self.indents.pop()
self.flow_level -= 1
if self.canonical:
self.write_indicator(u',', False)
self.write_indent()
self.write_indicator(u'}', False)
self.state = self.states.pop()
else:
self.write_indicator(u',', False)
if self.canonical or self.column > self.best_width:
self.write_indent()
if not self.canonical and self.check_simple_key():
self.states.append(self.expect_flow_mapping_simple_value)
self.expect_node(mapping=True, simple_key=True)
else:
self.write_indicator(u'?', True)
self.states.append(self.expect_flow_mapping_value)
self.expect_node(mapping=True)
def expect_flow_mapping_simple_value(self):
self.write_indicator(u':', False)
self.states.append(self.expect_flow_mapping_key)
self.expect_node(mapping=True)
def expect_flow_mapping_value(self):
if self.canonical or self.column > self.best_width:
self.write_indent()
self.write_indicator(u':', True)
self.states.append(self.expect_flow_mapping_key)
self.expect_node(mapping=True)
# Block sequence handlers.
def expect_block_sequence(self):
indentless = (self.mapping_context and not self.indention)
self.increase_indent(flow=False, indentless=indentless)
self.state = self.expect_first_block_sequence_item
def expect_first_block_sequence_item(self):
return self.expect_block_sequence_item(first=True)
def expect_block_sequence_item(self, first=False):
if not first and isinstance(self.event, SequenceEndEvent):
self.indent = self.indents.pop()
self.state = self.states.pop()
else:
self.write_indent()
self.write_indicator(u'-', True, indention=True)
self.states.append(self.expect_block_sequence_item)
self.expect_node(sequence=True)
# Block mapping handlers.
def expect_block_mapping(self):
self.increase_indent(flow=False)
self.state = self.expect_first_block_mapping_key
def expect_first_block_mapping_key(self):
return self.expect_block_mapping_key(first=True)
def expect_block_mapping_key(self, first=False):
if not first and isinstance(self.event, MappingEndEvent):
self.indent = self.indents.pop()
self.state = self.states.pop()
else:
self.write_indent()
if self.check_simple_key():
self.states.append(self.expect_block_mapping_simple_value)
self.expect_node(mapping=True, simple_key=True)
else:
self.write_indicator(u'?', True, indention=True)
self.states.append(self.expect_block_mapping_value)
self.expect_node(mapping=True)
def expect_block_mapping_simple_value(self):
self.write_indicator(u':', False)
self.states.append(self.expect_block_mapping_key)
self.expect_node(mapping=True)
def expect_block_mapping_value(self):
self.write_indent()
self.write_indicator(u':', True, indention=True)
self.states.append(self.expect_block_mapping_key)
self.expect_node(mapping=True)
# Checkers.
def check_empty_sequence(self):
return (isinstance(self.event, SequenceStartEvent) and self.events
and isinstance(self.events[0], SequenceEndEvent))
def check_empty_mapping(self):
return (isinstance(self.event, MappingStartEvent) and self.events
and isinstance(self.events[0], MappingEndEvent))
def check_empty_document(self):
if not isinstance(self.event, DocumentStartEvent) or not self.events:
return False
event = self.events[0]
return (isinstance(event, ScalarEvent) and event.anchor is None
and event.tag is None and event.implicit and event.value == u'')
def check_simple_key(self):
length = 0
if isinstance(self.event, NodeEvent) and self.event.anchor is not None:
if self.prepared_anchor is None:
self.prepared_anchor = self.prepare_anchor(self.event.anchor)
length += len(self.prepared_anchor)
if isinstance(self.event, (ScalarEvent, CollectionStartEvent)) \
and self.event.tag is not None:
if self.prepared_tag is None:
self.prepared_tag = self.prepare_tag(self.event.tag)
length += len(self.prepared_tag)
if isinstance(self.event, ScalarEvent):
if self.analysis is None:
self.analysis = self.analyze_scalar(self.event.value)
length += len(self.analysis.scalar)
return (length < 128 and (isinstance(self.event, AliasEvent)
or (isinstance(self.event, ScalarEvent)
and not self.analysis.empty and not self.analysis.multiline)
or self.check_empty_sequence() or self.check_empty_mapping()))
# Anchor, Tag, and Scalar processors.
def process_anchor(self, indicator):
if self.event.anchor is None:
self.prepared_anchor = None
return
if self.prepared_anchor is None:
self.prepared_anchor = self.prepare_anchor(self.event.anchor)
if self.prepared_anchor:
self.write_indicator(indicator+self.prepared_anchor, True)
self.prepared_anchor = None
def process_tag(self):
tag = self.event.tag
if isinstance(self.event, ScalarEvent):
if self.style is None:
self.style = self.choose_scalar_style()
if ((not self.canonical or tag is None) and
((self.style == '' and self.event.implicit[0])
or (self.style != '' and self.event.implicit[1]))):
self.prepared_tag = None
return
if self.event.implicit[0] and tag is None:
tag = u'!'
self.prepared_tag = None
else:
if (not self.canonical or tag is None) and self.event.implicit:
self.prepared_tag = None
return
if tag is None:
raise EmitterError("tag is not specified")
if self.prepared_tag is None:
self.prepared_tag = self.prepare_tag(tag)
if self.prepared_tag:
self.write_indicator(self.prepared_tag, True)
self.prepared_tag = None
def choose_scalar_style(self):
if self.analysis is None:
self.analysis = self.analyze_scalar(self.event.value)
if self.event.style == '"' or self.canonical:
return '"'
if not self.event.style and self.event.implicit[0]:
if (not (self.simple_key_context and
(self.analysis.empty or self.analysis.multiline))
and (self.flow_level and self.analysis.allow_flow_plain
or (not self.flow_level and self.analysis.allow_block_plain))):
return ''
if self.event.style and self.event.style in '|>':
if (not self.flow_level and not self.simple_key_context
and self.analysis.allow_block):
return self.event.style
if not self.event.style or self.event.style == '\'':
if (self.analysis.allow_single_quoted and
not (self.simple_key_context and self.analysis.multiline)):
return '\''
return '"'
def process_scalar(self):
if self.analysis is None:
self.analysis = self.analyze_scalar(self.event.value)
if self.style is None:
self.style = self.choose_scalar_style()
split = (not self.simple_key_context)
#if self.analysis.multiline and split \
# and (not self.style or self.style in '\'\"'):
# self.write_indent()
if self.style == '"':
self.write_double_quoted(self.analysis.scalar, split)
elif self.style == '\'':
self.write_single_quoted(self.analysis.scalar, split)
elif self.style == '>':
self.write_folded(self.analysis.scalar)
elif self.style == '|':
self.write_literal(self.analysis.scalar)
else:
self.write_plain(self.analysis.scalar, split)
self.analysis = None
self.style = None
# Analyzers.
def prepare_version(self, version):
major, minor = version
if major != 1:
raise EmitterError("unsupported YAML version: %d.%d" % (major, minor))
return u'%d.%d' % (major, minor)
def prepare_tag_handle(self, handle):
if not handle:
raise EmitterError("tag handle must not be empty")
if handle[0] != u'!' or handle[-1] != u'!':
raise EmitterError("tag handle must start and end with '!': %r"
% (handle.encode('utf-8')))
for ch in handle[1:-1]:
if not (u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z' \
or ch in u'-_'):
raise EmitterError("invalid character %r in the tag handle: %r"
% (ch.encode('utf-8'), handle.encode('utf-8')))
return handle
def prepare_tag_prefix(self, prefix):
if not prefix:
raise EmitterError("tag prefix must not be empty")
chunks = []
start = end = 0
if prefix[0] == u'!':
end = 1
while end < len(prefix):
ch = prefix[end]
if u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z' \
or ch in u'-;/?!:@&=+$,_.~*\'()[]':
end += 1
else:
if start < end:
chunks.append(prefix[start:end])
start = end = end+1
data = ch.encode('utf-8')
for ch in data:
chunks.append(u'%%%02X' % ord(ch))
if start < end:
chunks.append(prefix[start:end])
return u''.join(chunks)
def prepare_tag(self, tag):
if not tag:
raise EmitterError("tag must not be empty")
if tag == u'!':
return tag
handle = None
suffix = tag
prefixes = self.tag_prefixes.keys()
prefixes.sort()
for prefix in prefixes:
if tag.startswith(prefix) \
and (prefix == u'!' or len(prefix) < len(tag)):
handle = self.tag_prefixes[prefix]
suffix = tag[len(prefix):]
chunks = []
start = end = 0
while end < len(suffix):
ch = suffix[end]
if u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z' \
or ch in u'-;/?:@&=+$,_.~*\'()[]' \
or (ch == u'!' and handle != u'!'):
end += 1
else:
if start < end:
chunks.append(suffix[start:end])
start = end = end+1
data = ch.encode('utf-8')
for ch in data:
chunks.append(u'%%%02X' % ord(ch))
if start < end:
chunks.append(suffix[start:end])
suffix_text = u''.join(chunks)
if handle:
return u'%s%s' % (handle, suffix_text)
else:
return u'!<%s>' % suffix_text
def prepare_anchor(self, anchor):
if not anchor:
raise EmitterError("anchor must not be empty")
for ch in anchor:
if not (u'0' <= ch <= u'9' or u'A' <= ch <= u'Z' or u'a' <= ch <= u'z' \
or ch in u'-_'):
raise EmitterError("invalid character %r in the anchor: %r"
% (ch.encode('utf-8'), anchor.encode('utf-8')))
return anchor
def analyze_scalar(self, scalar):
# Empty scalar is a special case.
if not scalar:
return ScalarAnalysis(scalar=scalar, empty=True, multiline=False,
allow_flow_plain=False, allow_block_plain=True,
allow_single_quoted=True, allow_double_quoted=True,
allow_block=False)
# Indicators and special characters.
block_indicators = False
flow_indicators = False
line_breaks = False
special_characters = False
# Important whitespace combinations.
leading_space = False
leading_break = False
trailing_space = False
trailing_break = False
break_space = False
space_break = False
# Check document indicators.
if scalar.startswith(u'---') or scalar.startswith(u'...'):
block_indicators = True
flow_indicators = True
# First character or preceded by a whitespace.
preceeded_by_whitespace = True
# Last character or followed by a whitespace.
followed_by_whitespace = (len(scalar) == 1 or
scalar[1] in u'\0 \t\r\n\x85\u2028\u2029')
# The previous character is a space.
previous_space = False
# The previous character is a break.
previous_break = False
index = 0
while index < len(scalar):
ch = scalar[index]
# Check for indicators.
if index == 0:
# Leading indicators are special characters.
if ch in u'#,[]{}&*!|>\'\"%@`':
flow_indicators = True
block_indicators = True
if ch in u'?:':
flow_indicators = True
if followed_by_whitespace:
block_indicators = True
if ch == u'-' and followed_by_whitespace:
flow_indicators = True
block_indicators = True
else:
# Some indicators cannot appear within a scalar as well.
if ch in u',?[]{}':
flow_indicators = True
if ch == u':':
flow_indicators = True
if followed_by_whitespace:
block_indicators = True
if ch == u'#' and preceeded_by_whitespace:
flow_indicators = True
block_indicators = True
# Check for line breaks, special, and unicode characters.
if ch in u'\n\x85\u2028\u2029':
line_breaks = True
if not (ch == u'\n' or u'\x20' <= ch <= u'\x7E'):
if (ch == u'\x85' or u'\xA0' <= ch <= u'\uD7FF'
or u'\uE000' <= ch <= u'\uFFFD') and ch != u'\uFEFF':
unicode_characters = True
if not self.allow_unicode:
special_characters = True
else:
special_characters = True
# Detect important whitespace combinations.
if ch == u' ':
if index == 0:
leading_space = True
if index == len(scalar)-1:
trailing_space = True
if previous_break:
break_space = True
previous_space = True
previous_break = False
elif ch in u'\n\x85\u2028\u2029':
if index == 0:
leading_break = True
if index == len(scalar)-1:
trailing_break = True
if previous_space:
space_break = True
previous_space = False
previous_break = True
else:
previous_space = False
previous_break = False
# Prepare for the next character.
index += 1
preceeded_by_whitespace = (ch in u'\0 \t\r\n\x85\u2028\u2029')
followed_by_whitespace = (index+1 >= len(scalar) or
scalar[index+1] in u'\0 \t\r\n\x85\u2028\u2029')
# Let's decide what styles are allowed.
allow_flow_plain = True
allow_block_plain = True
allow_single_quoted = True
allow_double_quoted = True
allow_block = True
# Leading and trailing whitespaces are bad for plain scalars.
if (leading_space or leading_break
or trailing_space or trailing_break):
allow_flow_plain = allow_block_plain = False
# We do not permit trailing spaces for block scalars.
if trailing_space:
allow_block = False
# Spaces at the beginning of a new line are only acceptable for block
# scalars.
if break_space:
allow_flow_plain = allow_block_plain = allow_single_quoted = False
# Spaces followed by breaks, as well as special character are only
# allowed for double quoted scalars.
if space_break or special_characters:
allow_flow_plain = allow_block_plain = \
allow_single_quoted = allow_block = False
# Although the plain scalar writer supports breaks, we never emit
# multiline plain scalars.
if line_breaks:
allow_flow_plain = allow_block_plain = False
# Flow indicators are forbidden for flow plain scalars.
if flow_indicators:
allow_flow_plain = False
# Block indicators are forbidden for block plain scalars.
if block_indicators:
allow_block_plain = False
return ScalarAnalysis(scalar=scalar,
empty=False, multiline=line_breaks,
allow_flow_plain=allow_flow_plain,
allow_block_plain=allow_block_plain,
allow_single_quoted=allow_single_quoted,
allow_double_quoted=allow_double_quoted,
allow_block=allow_block)
# Writers.
def flush_stream(self):
if hasattr(self.stream, 'flush'):
self.stream.flush()
def write_stream_start(self):
# Write BOM if needed.
if self.encoding and self.encoding.startswith('utf-16'):
self.stream.write(u'\uFEFF'.encode(self.encoding))
def write_stream_end(self):
self.flush_stream()
def write_indicator(self, indicator, need_whitespace,
whitespace=False, indention=False):
if self.whitespace or not need_whitespace:
data = indicator
else:
data = u' '+indicator
self.whitespace = whitespace
self.indention = self.indention and indention
self.column += len(data)
self.open_ended = False
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
def write_indent(self):
indent = self.indent or 0
if not self.indention or self.column > indent \
or (self.column == indent and not self.whitespace):
self.write_line_break()
if self.column < indent:
self.whitespace = True
data = u' '*(indent-self.column)
self.column = indent
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
def write_line_break(self, data=None):
if data is None:
data = self.best_line_break
self.whitespace = True
self.indention = True
self.line += 1
self.column = 0
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
def write_version_directive(self, version_text):
data = u'%%YAML %s' % version_text
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
self.write_line_break()
def write_tag_directive(self, handle_text, prefix_text):
data = u'%%TAG %s %s' % (handle_text, prefix_text)
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
self.write_line_break()
# Scalar streams.
def write_single_quoted(self, text, split=True):
self.write_indicator(u'\'', True)
spaces = False
breaks = False
start = end = 0
while end <= len(text):
ch = None
if end < len(text):
ch = text[end]
if spaces:
if ch is None or ch != u' ':
if start+1 == end and self.column > self.best_width and split \
and start != 0 and end != len(text):
self.write_indent()
else:
data = text[start:end]
self.column += len(data)
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
start = end
elif breaks:
if ch is None or ch not in u'\n\x85\u2028\u2029':
if text[start] == u'\n':
self.write_line_break()
for br in text[start:end]:
if br == u'\n':
self.write_line_break()
else:
self.write_line_break(br)
self.write_indent()
start = end
else:
if ch is None or ch in u' \n\x85\u2028\u2029' or ch == u'\'':
if start < end:
data = text[start:end]
self.column += len(data)
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
start = end
if ch == u'\'':
data = u'\'\''
self.column += 2
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
start = end + 1
if ch is not None:
spaces = (ch == u' ')
breaks = (ch in u'\n\x85\u2028\u2029')
end += 1
self.write_indicator(u'\'', False)
ESCAPE_REPLACEMENTS = {
u'\0': u'0',
u'\x07': u'a',
u'\x08': u'b',
u'\x09': u't',
u'\x0A': u'n',
u'\x0B': u'v',
u'\x0C': u'f',
u'\x0D': u'r',
u'\x1B': u'e',
u'\"': u'\"',
u'\\': u'\\',
u'\x85': u'N',
u'\xA0': u'_',
u'\u2028': u'L',
u'\u2029': u'P',
}
def write_double_quoted(self, text, split=True):
self.write_indicator(u'"', True)
start = end = 0
while end <= len(text):
ch = None
if end < len(text):
ch = text[end]
if ch is None or ch in u'"\\\x85\u2028\u2029\uFEFF' \
or not (u'\x20' <= ch <= u'\x7E'
or (self.allow_unicode
and (u'\xA0' <= ch <= u'\uD7FF'
or u'\uE000' <= ch <= u'\uFFFD'))):
if start < end:
data = text[start:end]
self.column += len(data)
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
start = end
if ch is not None:
if ch in self.ESCAPE_REPLACEMENTS:
data = u'\\'+self.ESCAPE_REPLACEMENTS[ch]
elif ch <= u'\xFF':
data = u'\\x%02X' % ord(ch)
elif ch <= u'\uFFFF':
data = u'\\u%04X' % ord(ch)
else:
data = u'\\U%08X' % ord(ch)
self.column += len(data)
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
start = end+1
if 0 < end < len(text)-1 and (ch == u' ' or start >= end) \
and self.column+(end-start) > self.best_width and split:
data = text[start:end]+u'\\'
if start < end:
start = end
self.column += len(data)
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
self.write_indent()
self.whitespace = False
self.indention = False
if text[start] == u' ':
data = u'\\'
self.column += len(data)
if self.encoding:
data = data.encode(self.encoding)
self.stream.write(data)
end += 1
self.write_indicator(u'"', False)
def determine_block_hints(self, text):
hints = u''
if text:
if text[0] in u' \n\x85\u2028\u2029':
hints += unicode(self.best_indent)
if text[-1] not in u'\n\x85\u2028\u2029':
hints += u'-'
elif len(text) == 1 or text[-2] in u'\n\x85\u2028\u2029':
hints += u'+'
return hints
def write_folded(self, text):
hints = self.determine_block_hints(text)
self.write_indicator(u'>'+hints, True)
if hints[-1:] == u'+':
self.open_ended = True
self.write_line_break()
leading_space = True
You can’t perform that action at this time.