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
|
# Copyright 2015 Google Inc. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Decide what the format for the code should be.
The `unwrapped_line.UnwrappedLine`s are now ready to be formatted.
UnwrappedLines that can be merged together are. The best formatting is returned
as a string.
Reformat(): the main function exported by this module.
"""
from __future__ import unicode_literals
import collections
import heapq
import re
from lib2to3 import pytree
from lib2to3.pgen2 import token
from yapf.yapflib import format_decision_state
from yapf.yapflib import format_token
from yapf.yapflib import line_joiner
from yapf.yapflib import pytree_utils
from yapf.yapflib import style
from yapf.yapflib import verifier
def Reformat(uwlines, verify=False, lines=None):
"""Reformat the unwrapped lines.
Arguments:
uwlines: (list of unwrapped_line.UnwrappedLine) Lines we want to format.
verify: (bool) True if reformatted code should be verified for syntax.
lines: (set of int) The lines which can be modified or None if there is no
line range restriction.
Returns:
A string representing the reformatted code.
"""
final_lines = []
prev_uwline = None # The previous line.
indent_width = style.Get('INDENT_WIDTH')
for uwline in _SingleOrMergedLines(uwlines):
first_token = uwline.first
_FormatFirstToken(first_token, uwline.depth, prev_uwline, final_lines)
indent_amt = indent_width * uwline.depth
state = format_decision_state.FormatDecisionState(uwline, indent_amt)
state.MoveStateToNextToken()
if not uwline.disable:
if uwline.first.is_comment:
uwline.first.node.value = uwline.first.node.value.rstrip()
elif uwline.last.is_comment:
uwline.last.node.value = uwline.last.node.value.rstrip()
if prev_uwline and prev_uwline.disable:
# Keep the vertical spacing between a disabled and enabled formatting
# region.
_RetainRequiredVerticalSpacingBetweenTokens(uwline.first,
prev_uwline.last, lines)
if any(tok.is_comment for tok in uwline.tokens):
_RetainVerticalSpacingBeforeComments(uwline)
if (_LineContainsI18n(uwline) or uwline.disable or
_LineHasContinuationMarkers(uwline)):
_RetainHorizontalSpacing(uwline)
_RetainRequiredVerticalSpacing(uwline, prev_uwline, lines)
_EmitLineUnformatted(state)
elif _CanPlaceOnSingleLine(uwline) and not any(tok.must_split
for tok in uwline.tokens):
# The unwrapped line fits on one line.
while state.next_token:
state.AddTokenToState(newline=False, dry_run=False)
else:
if not _AnalyzeSolutionSpace(state):
# Failsafe mode. If there isn't a solution to the line, then just emit
# it as is.
state = format_decision_state.FormatDecisionState(uwline, indent_amt)
state.MoveStateToNextToken()
_RetainHorizontalSpacing(uwline)
_RetainRequiredVerticalSpacing(uwline, prev_uwline, None)
_EmitLineUnformatted(state)
final_lines.append(uwline)
prev_uwline = uwline
return _FormatFinalLines(final_lines, verify)
def _RetainHorizontalSpacing(uwline):
"""Retain all horizontal spacing between tokens."""
for tok in uwline.tokens:
tok.RetainHorizontalSpacing(uwline.first.column, uwline.depth)
def _RetainRequiredVerticalSpacing(cur_uwline, prev_uwline, lines):
prev_tok = None
if prev_uwline is not None:
prev_tok = prev_uwline.last
for cur_tok in cur_uwline.tokens:
_RetainRequiredVerticalSpacingBetweenTokens(cur_tok, prev_tok, lines)
prev_tok = cur_tok
def _RetainRequiredVerticalSpacingBetweenTokens(cur_tok, prev_tok, lines):
"""Retain vertical spacing between two tokens if not in editable range."""
if prev_tok is None:
return
if prev_tok.is_string:
prev_lineno = prev_tok.lineno + prev_tok.value.count('\n')
elif prev_tok.is_pseudo_paren:
if not prev_tok.previous_token.is_multiline_string:
prev_lineno = prev_tok.previous_token.lineno
else:
prev_lineno = prev_tok.lineno
else:
prev_lineno = prev_tok.lineno
if cur_tok.is_comment:
cur_lineno = cur_tok.lineno - cur_tok.value.count('\n')
else:
cur_lineno = cur_tok.lineno
if prev_tok.value.endswith('\\'):
prev_lineno += prev_tok.value.count('\n')
required_newlines = cur_lineno - prev_lineno
if cur_tok.is_comment and not prev_tok.is_comment:
# Don't adjust between a comment and non-comment.
pass
elif lines and (cur_lineno in lines or prev_lineno in lines):
desired_newlines = cur_tok.whitespace_prefix.count('\n')
whitespace_lines = range(prev_lineno + 1, cur_lineno)
deletable_lines = len(lines.intersection(whitespace_lines))
required_newlines = max(required_newlines - deletable_lines,
desired_newlines)
cur_tok.AdjustNewlinesBefore(required_newlines)
def _RetainVerticalSpacingBeforeComments(uwline):
"""Retain vertical spacing before comments."""
prev_token = None
for tok in uwline.tokens:
if tok.is_comment and prev_token:
if tok.lineno - tok.value.count('\n') - prev_token.lineno > 1:
tok.AdjustNewlinesBefore(ONE_BLANK_LINE)
prev_token = tok
def _EmitLineUnformatted(state):
"""Emit the line without formatting.
The line contains code that if reformatted would break a non-syntactic
convention. E.g., i18n comments and function calls are tightly bound by
convention. Instead, we calculate when / if a newline should occur and honor
that. But otherwise the code emitted will be the same as the original code.
Arguments:
state: (format_decision_state.FormatDecisionState) The format decision
state.
"""
prev_lineno = None
while state.next_token:
previous_token = state.next_token.previous_token
previous_lineno = previous_token.lineno
if previous_token.is_multiline_string or previous_token.is_string:
previous_lineno += previous_token.value.count('\n')
if previous_token.is_continuation:
newline = False
else:
newline = (
prev_lineno is not None and state.next_token.lineno > previous_lineno)
prev_lineno = state.next_token.lineno
state.AddTokenToState(newline=newline, dry_run=False)
def _LineContainsI18n(uwline):
"""Return true if there are i18n comments or function calls in the line.
I18n comments and pseudo-function calls are closely related. They cannot
be moved apart without breaking i18n.
Arguments:
uwline: (unwrapped_line.UnwrappedLine) The line currently being formatted.
Returns:
True if the line contains i18n comments or function calls. False otherwise.
"""
if style.Get('I18N_COMMENT'):
for tok in uwline.tokens:
if tok.is_comment and re.match(style.Get('I18N_COMMENT'), tok.value):
# Contains an i18n comment.
return True
if style.Get('I18N_FUNCTION_CALL'):
length = len(uwline.tokens)
index = 0
while index < length - 1:
if (uwline.tokens[index + 1].value == '(' and
uwline.tokens[index].value in style.Get('I18N_FUNCTION_CALL')):
return True
index += 1
return False
def _LineHasContinuationMarkers(uwline):
"""Return true if the line has continuation markers in it."""
return any(tok.is_continuation for tok in uwline.tokens)
def _CanPlaceOnSingleLine(uwline):
"""Determine if the unwrapped line can go on a single line.
Arguments:
uwline: (unwrapped_line.UnwrappedLine) The line currently being formatted.
Returns:
True if the line can or should be added to a single line. False otherwise.
"""
indent_amt = style.Get('INDENT_WIDTH') * uwline.depth
last = uwline.last
last_index = -1
if last.is_pylint_comment or last.is_pytype_comment:
last = last.previous_token
last_index = -2
if last is None:
return True
return (last.total_length + indent_amt <= style.Get('COLUMN_LIMIT') and
not any(tok.is_comment for tok in uwline.tokens[:last_index]))
def _FormatFinalLines(final_lines, verify):
"""Compose the final output from the finalized lines."""
formatted_code = []
for line in final_lines:
formatted_line = []
for tok in line.tokens:
if not tok.is_pseudo_paren:
formatted_line.append(tok.whitespace_prefix)
formatted_line.append(tok.value)
else:
if (not tok.next_token.whitespace_prefix.startswith('\n') and
not tok.next_token.whitespace_prefix.startswith(' ')):
if (tok.previous_token.value == ':' or
tok.next_token.value not in ',}])'):
formatted_line.append(' ')
formatted_code.append(''.join(formatted_line))
if verify:
verifier.VerifyCode(formatted_code[-1])
return ''.join(formatted_code) + '\n'
class _StateNode(object):
"""An edge in the solution space from 'previous.state' to 'state'.
Attributes:
state: (format_decision_state.FormatDecisionState) The format decision state
for this node.
newline: If True, then on the edge from 'previous.state' to 'state' a
newline is inserted.
previous: (_StateNode) The previous state node in the graph.
"""
# TODO(morbo): Add a '__cmp__' method.
def __init__(self, state, newline, previous):
self.state = state.Clone()
self.newline = newline
self.previous = previous
def __repr__(self): # pragma: no cover
return 'StateNode(state=[\n{0}\n], newline={1})'.format(
self.state, self.newline)
# A tuple of (penalty, count) that is used to prioritize the BFS. In case of
# equal penalties, we prefer states that were inserted first. During state
# generation, we make sure that we insert states first that break the line as
# late as possible.
_OrderedPenalty = collections.namedtuple('OrderedPenalty', ['penalty', 'count'])
# An item in the prioritized BFS search queue. The 'StateNode's 'state' has
# the given '_OrderedPenalty'.
_QueueItem = collections.namedtuple('QueueItem',
['ordered_penalty', 'state_node'])
def _AnalyzeSolutionSpace(initial_state):
"""Analyze the entire solution space starting from initial_state.
This implements a variant of Dijkstra's algorithm on the graph that spans
the solution space (LineStates are the nodes). The algorithm tries to find
the shortest path (the one with the lowest penalty) from 'initial_state' to
the state where all tokens are placed.
Arguments:
initial_state: (format_decision_state.FormatDecisionState) The initial state
to start the search from.
Returns:
True if a formatting solution was found. False otherwise.
"""
count = 0
seen = set()
p_queue = []
# Insert start element.
node = _StateNode(initial_state, False, None)
heapq.heappush(p_queue, _QueueItem(_OrderedPenalty(0, count), node))
count += 1
while p_queue:
item = p_queue[0]
penalty = item.ordered_penalty.penalty
node = item.state_node
if not node.state.next_token:
break
heapq.heappop(p_queue)
if count > 10000:
node.state.ignore_stack_for_comparison = True
if node.state in seen:
continue
seen.add(node.state)
# FIXME(morbo): Add a 'decision' element?
count = _AddNextStateToQueue(penalty, node, False, count, p_queue)
count = _AddNextStateToQueue(penalty, node, True, count, p_queue)
if not p_queue:
# We weren't able to find a solution. Do nothing.
return False
_ReconstructPath(initial_state, heapq.heappop(p_queue).state_node)
return True
def _AddNextStateToQueue(penalty, previous_node, newline, count, p_queue):
"""Add the following state to the analysis queue.
Assume the current state is 'previous_node' and has been reached with a
penalty of 'penalty'. Insert a line break if 'newline' is True.
Arguments:
penalty: (int) The penalty associated with the path up to this point.
previous_node: (_StateNode) The last _StateNode inserted into the priority
queue.
newline: (bool) Add a newline if True.
count: (int) The number of elements in the queue.
p_queue: (heapq) The priority queue representing the solution space.
Returns:
The updated number of elements in the queue.
"""
must_split = previous_node.state.MustSplit()
if newline and not previous_node.state.CanSplit(must_split):
# Don't add a newline if the token cannot be split.
return count
if not newline and must_split:
# Don't add a token we must split but where we aren't splitting.
return count
node = _StateNode(previous_node.state, newline, previous_node)
penalty += node.state.AddTokenToState(
newline=newline, dry_run=True, must_split=must_split)
heapq.heappush(p_queue, _QueueItem(_OrderedPenalty(penalty, count), node))
return count + 1
def _ReconstructPath(initial_state, current):
"""Reconstruct the path through the queue with lowest penalty.
Arguments:
initial_state: (format_decision_state.FormatDecisionState) The initial state
to start the search from.
current: (_StateNode) The node in the decision graph that is the end point
of the path with the least penalty.
"""
path = collections.deque()
while current.previous:
path.appendleft(current)
current = current.previous
for node in path:
initial_state.AddTokenToState(newline=node.newline, dry_run=False)
def _FormatFirstToken(first_token, indent_depth, prev_uwline, final_lines):
"""Format the first token in the unwrapped line.
Add a newline and the required indent before the first token of the unwrapped
line.
Arguments:
first_token: (format_token.FormatToken) The first token in the unwrapped
line.
indent_depth: (int) The line's indentation depth.
prev_uwline: (list of unwrapped_line.UnwrappedLine) The unwrapped line
previous to this line.
final_lines: (list of unwrapped_line.UnwrappedLine) The unwrapped lines
that have already been processed.
"""
first_token.AddWhitespacePrefix(
_CalculateNumberOfNewlines(first_token, indent_depth, prev_uwline,
final_lines),
indent_level=indent_depth)
NO_BLANK_LINES = 1
ONE_BLANK_LINE = 2
TWO_BLANK_LINES = 3
def _IsClassOrDef(uwline):
if uwline.first.value in {'class', 'def'}:
return True
return [t.value for t in uwline.tokens[:2]] == ['async', 'def']
def _CalculateNumberOfNewlines(first_token, indent_depth, prev_uwline,
final_lines):
"""Calculate the number of newlines we need to add.
Arguments:
first_token: (format_token.FormatToken) The first token in the unwrapped
line.
indent_depth: (int) The line's indentation depth.
prev_uwline: (list of unwrapped_line.UnwrappedLine) The unwrapped line
previous to this line.
final_lines: (list of unwrapped_line.UnwrappedLine) The unwrapped lines
that have already been processed.
Returns:
The number of newlines needed before the first token.
"""
# TODO(morbo): Special handling for imports.
# TODO(morbo): Create a knob that can tune these.
if prev_uwline is None:
# The first line in the file. Don't add blank lines.
# FIXME(morbo): Is this correct?
if first_token.newlines is not None:
pytree_utils.SetNodeAnnotation(first_token.node,
pytree_utils.Annotation.NEWLINES, None)
return 0
if first_token.is_docstring:
if (prev_uwline.first.value == 'class' and
style.Get('BLANK_LINE_BEFORE_CLASS_DOCSTRING')):
# Enforce a blank line before a class's docstring.
return ONE_BLANK_LINE
elif (prev_uwline.first.value.startswith('#') and
style.Get('BLANK_LINE_BEFORE_MODULE_DOCSTRING')):
# Enforce a blank line before a module's docstring.
return ONE_BLANK_LINE
# The docstring shouldn't have a newline before it.
return NO_BLANK_LINES
prev_last_token = prev_uwline.last
if prev_last_token.is_docstring:
if (not indent_depth and first_token.value in {'class', 'def', 'async'}):
# Separate a class or function from the module-level docstring with
# appropriate number of blank lines.
return 1 + style.Get('BLANK_LINES_AROUND_TOP_LEVEL_DEFINITION')
if _NoBlankLinesBeforeCurrentToken(prev_last_token.value, first_token,
prev_last_token):
return NO_BLANK_LINES
else:
return ONE_BLANK_LINE
if first_token.value in {'class', 'def', 'async', '@'}:
# TODO(morbo): This can go once the blank line calculator is more
# sophisticated.
if not indent_depth:
# This is a top-level class or function.
is_inline_comment = prev_last_token.whitespace_prefix.count('\n') == 0
if (not prev_uwline.disable and prev_last_token.is_comment and
not is_inline_comment):
# This token follows a non-inline comment.
if _NoBlankLinesBeforeCurrentToken(prev_last_token.value, first_token,
prev_last_token):
# Assume that the comment is "attached" to the current line.
# Therefore, we want two blank lines before the comment.
index = len(final_lines) - 1
while index > 0:
if not final_lines[index - 1].is_comment:
break
index -= 1
if final_lines[index - 1].first.value == '@':
final_lines[index].first.AdjustNewlinesBefore(NO_BLANK_LINES)
else:
prev_last_token.AdjustNewlinesBefore(
1 + style.Get('BLANK_LINES_AROUND_TOP_LEVEL_DEFINITION'))
if first_token.newlines is not None:
pytree_utils.SetNodeAnnotation(
first_token.node, pytree_utils.Annotation.NEWLINES, None)
return NO_BLANK_LINES
elif _IsClassOrDef(prev_uwline):
if not style.Get('BLANK_LINE_BEFORE_NESTED_CLASS_OR_DEF'):
pytree_utils.SetNodeAnnotation(first_token.node,
pytree_utils.Annotation.NEWLINES, None)
return NO_BLANK_LINES
# Calculate how many newlines were between the original lines. We want to
# retain that formatting if it doesn't violate one of the style guide rules.
if first_token.is_comment:
first_token_lineno = first_token.lineno - first_token.value.count('\n')
else:
first_token_lineno = first_token.lineno
prev_last_token_lineno = prev_last_token.lineno
if prev_last_token.is_multiline_string:
prev_last_token_lineno += prev_last_token.value.count('\n')
if first_token_lineno - prev_last_token_lineno > 1:
return ONE_BLANK_LINE
return NO_BLANK_LINES
def _SingleOrMergedLines(uwlines):
"""Generate the lines we want to format.
Arguments:
uwlines: (list of unwrapped_line.UnwrappedLine) Lines we want to format.
Yields:
Either a single line, if the current line cannot be merged with the
succeeding line, or the next two lines merged into one line.
"""
index = 0
last_was_merged = False
while index < len(uwlines):
if uwlines[index].disable:
uwline = uwlines[index]
index += 1
while index < len(uwlines):
column = uwline.last.column + 2
if uwlines[index].lineno != uwline.lineno:
break
if uwline.last.value != ':':
leaf = pytree.Leaf(
type=token.SEMI, value=';', context=('', (uwline.lineno, column)))
uwline.AppendToken(format_token.FormatToken(leaf))
for tok in uwlines[index].tokens:
uwline.AppendToken(tok)
index += 1
yield uwline
elif line_joiner.CanMergeMultipleLines(uwlines[index:], last_was_merged):
# TODO(morbo): This splice is potentially very slow. Come up with a more
# performance-friendly way of determining if two lines can be merged.
next_uwline = uwlines[index + 1]
for tok in next_uwline.tokens:
uwlines[index].AppendToken(tok)
if (len(next_uwline.tokens) == 1 and
next_uwline.first.is_multiline_string):
# This may be a multiline shebang. In that case, we want to retain the
# formatting. Otherwise, it could mess up the shell script's syntax.
uwlines[index].disable = True
yield uwlines[index]
index += 2
last_was_merged = True
else:
yield uwlines[index]
index += 1
last_was_merged = False
def _NoBlankLinesBeforeCurrentToken(text, cur_token, prev_token):
"""Determine if there are no blank lines before the current token.
The previous token is a docstring or comment. The prev_token_lineno is the
start of the text of that token. Counting the number of newlines in its text
gives us the extent and thus where the line number of the end of the
docstring or comment. After that, we just compare it to the current token's
line number to see if there are blank lines between them.
Arguments:
text: (unicode) The text of the docstring or comment before the current
token.
cur_token: (format_token.FormatToken) The current token in the unwrapped
line.
prev_token: (format_token.FormatToken) The previous token in the unwrapped
line.
Returns:
True if there is no blank line before the current token.
"""
cur_token_lineno = cur_token.lineno
if cur_token.is_comment:
cur_token_lineno -= cur_token.value.count('\n')
num_newlines = text.count('\n') if not prev_token.is_comment else 0
return prev_token.lineno + num_newlines == cur_token_lineno - 1
|