config/check_spidermonkey_style.py

   1 # vim: set ts=8 sts=4 et sw=4 tw=99:
   2 # This Source Code Form is subject to the terms of the Mozilla Public
   3 # License, v. 2.0. If a copy of the MPL was not distributed with this
   4 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
   5
   6 # ----------------------------------------------------------------------------
   7 # This script checks various aspects of SpiderMonkey code style.  The current checks are as
   8 # follows.
   9 #
  10 # We check the following things in headers.
  11 #
  12 # - No cyclic dependencies.
  13 #
  14 # - No normal header should #include a inlines.h/-inl.h file.
  15 #
  16 # - #ifndef wrappers should have the right form. (XXX: not yet implemented)
  17 #   - Every header file should have one.
  18 #   - The guard name used should be appropriate for the filename.
  19 #
  20 # We check the following things in all files.
  21 #
  22 # - #includes should have full paths, e.g. "jit/Ion.h", not "Ion.h".
  23 #
  24 # - #includes should use the appropriate form for system headers (<...>) and
  25 #   local headers ("...").
  26 #
  27 # - #includes should be ordered correctly.
  28 #   - Each one should be in the correct section.
  29 #   - Alphabetical order should be used within sections.
  30 #   - Sections should be in the right order.
  31 #   Note that the presence of #if/#endif blocks complicates things, to the
  32 #   point that it's not always clear where a conditionally-compiled #include
  33 #   statement should go, even to a human.  Therefore, we check the #include
  34 #   statements within each #if/#endif block (including nested ones) in
  35 #   isolation, but don't try to do any order checking between such blocks.
  36 # ----------------------------------------------------------------------------
  37
  38 from __future__ import print_function
  39
  40 import difflib
  41 import os
  42 import re
  43 import sys
  44
  45 # We don't bother checking files in these directories, because they're (a) auxiliary or (b)
  46 # imported code that doesn't follow our coding style.
  47 ignored_js_src_dirs = [
  48     'js/src/config/',            # auxiliary stuff
  49     'js/src/ctypes/libffi/',     # imported code
  50     'js/src/devtools/',          # auxiliary stuff
  51     'js/src/editline/',          # imported code
  52     'js/src/gdb/',               # auxiliary stuff
  53     'js/src/vtune/'              # imported code
  54 ]
  55
  56 # We ignore #includes of these files, because they don't follow the usual rules.
  57 included_inclnames_to_ignore = set([
  58     'ffi.h',                    # generated in ctypes/libffi/
  59     'devtools/sharkctl.h',      # we ignore devtools/ in general
  60     'devtools/Instruments.h',   # we ignore devtools/ in general
  61     'double-conversion/double-conversion.h',  # strange MFBT case
  62     'javascript-trace.h',       # generated in $OBJDIR if HAVE_DTRACE is defined
  63     'frontend/ReservedWordsGenerated.h',  # generated in $OBJDIR
  64     'gc/StatsPhasesGenerated.h',         # generated in $OBJDIR
  65     'gc/StatsPhasesGenerated.cpp',       # generated in $OBJDIR
  66     'jit/LOpcodes.h',           # generated in $OBJDIR
  67     'jit/MOpcodes.h',           # generated in $OBJDIR
  68     'jscustomallocator.h',      # provided by embedders;  allowed to be missing
  69     'js-config.h',              # generated in $OBJDIR
  70     'fdlibm.h',                 # fdlibm
  71     'FuzzerDefs.h',             # included without a path
  72     'FuzzingInterface.h',       # included without a path
  73     'mozmemory.h',              # included without a path
  74     'pratom.h',                 # NSPR
  75     'prcvar.h',                 # NSPR
  76     'prerror.h',                # NSPR
  77     'prinit.h',                 # NSPR
  78     'prio.h',                   # NSPR
  79     'private/pprio.h',          # NSPR
  80     'prlink.h',                 # NSPR
  81     'prlock.h',                 # NSPR
  82     'prprf.h',                  # NSPR
  83     'prthread.h',               # NSPR
  84     'prtypes.h',                # NSPR
  85     'selfhosted.out.h',         # generated in $OBJDIR
  86     'shellmoduleloader.out.h',  # generated in $OBJDIR
  87     'unicode/timezone.h',       # ICU
  88     'unicode/plurrule.h',       # ICU
  89     'unicode/ucal.h',           # ICU
  90     'unicode/uchar.h',          # ICU
  91     'unicode/uclean.h',         # ICU
  92     'unicode/ucol.h',           # ICU
  93     'unicode/udat.h',           # ICU
  94     'unicode/udatpg.h',         # ICU
  95     'unicode/udisplaycontext.h',  # ICU
  96     'unicode/uenum.h',          # ICU
  97     'unicode/uloc.h',           # ICU
  98     'unicode/unistr.h',         # ICU
  99     'unicode/unorm2.h',         # ICU
 100     'unicode/unum.h',           # ICU
 101     'unicode/unumsys.h',        # ICU
 102     'unicode/upluralrules.h',   # ICU
 103     'unicode/ureldatefmt.h',    # ICU
 104     'unicode/ustring.h',        # ICU
 105     'unicode/utypes.h',         # ICU
 106     'vtune/VTuneWrapper.h'      # VTune
 107 ])
 108
 109 # These files have additional constraints on where they are #included, so we
 110 # ignore #includes of them when checking #include ordering.
 111 oddly_ordered_inclnames = set([
 112     'ctypes/typedefs.h',        # Included multiple times in the body of ctypes/CTypes.h
 113     'frontend/BinSource-auto.h',  # Included in the body of frontend/BinSource.h
 114     # Included in the body of frontend/TokenStream.h
 115     'frontend/ReservedWordsGenerated.h',
 116     'gc/StatsPhasesGenerated.h',         # Included in the body of gc/Statistics.h
 117     'gc/StatsPhasesGenerated.cpp',       # Included in the body of gc/Statistics.cpp
 118     'psapi.h',                  # Must be included after "util/Windows.h" on Windows
 119     'machine/endian.h',         # Must be included after <sys/types.h> on BSD
 120     'winbase.h',                # Must precede other system headers(?)
 121     'windef.h'                  # Must precede other system headers(?)
 122 ])
 123
 124 # The files in tests/style/ contain code that fails this checking in various
 125 # ways.  Here is the output we expect.  If the actual output differs from
 126 # this, one of the following must have happened.
 127 # - New SpiderMonkey code violates one of the checked rules.
 128 # - The tests/style/ files have changed without expected_output being changed
 129 #   accordingly.
 130 # - This script has been broken somehow.
 131 #
 132 expected_output = '''\
 133 js/src/tests/style/BadIncludes2.h:1: error:
 134     vanilla header includes an inline-header file "tests/style/BadIncludes2-inl.h"
 135
 136 js/src/tests/style/BadIncludes.h:3: error:
 137     the file includes itself
 138
 139 js/src/tests/style/BadIncludes.h:6: error:
 140     "BadIncludes2.h" is included using the wrong path;
 141     did you forget a prefix, or is the file not yet committed?
 142
 143 js/src/tests/style/BadIncludes.h:8: error:
 144     <tests/style/BadIncludes2.h> should be included using
 145     the #include "..." form
 146
 147 js/src/tests/style/BadIncludes.h:10: error:
 148     "stdio.h" is included using the wrong path;
 149     did you forget a prefix, or is the file not yet committed?
 150
 151 js/src/tests/style/BadIncludesOrder-inl.h:5:6: error:
 152     "vm/JSScript-inl.h" should be included after "vm/Interpreter-inl.h"
 153
 154 js/src/tests/style/BadIncludesOrder-inl.h:6:7: error:
 155     "vm/Interpreter-inl.h" should be included after "js/Value.h"
 156
 157 js/src/tests/style/BadIncludesOrder-inl.h:7:8: error:
 158     "js/Value.h" should be included after "ds/LifoAlloc.h"
 159
 160 js/src/tests/style/BadIncludesOrder-inl.h:8:9: error:
 161     "ds/LifoAlloc.h" should be included after "jsapi.h"
 162
 163 js/src/tests/style/BadIncludesOrder-inl.h:9:10: error:
 164     "jsapi.h" should be included after <stdio.h>
 165
 166 js/src/tests/style/BadIncludesOrder-inl.h:10:11: error:
 167     <stdio.h> should be included after "mozilla/HashFunctions.h"
 168
 169 js/src/tests/style/BadIncludesOrder-inl.h:28:29: error:
 170     "vm/JSScript.h" should be included after "vm/JSFunction.h"
 171
 172 (multiple files): error:
 173     header files form one or more cycles
 174
 175    tests/style/HeaderCycleA1.h
 176    -> tests/style/HeaderCycleA2.h
 177       -> tests/style/HeaderCycleA3.h
 178          -> tests/style/HeaderCycleA1.h
 179
 180    tests/style/HeaderCycleB1-inl.h
 181    -> tests/style/HeaderCycleB2-inl.h
 182       -> tests/style/HeaderCycleB3-inl.h
 183          -> tests/style/HeaderCycleB4-inl.h
 184             -> tests/style/HeaderCycleB1-inl.h
 185             -> tests/style/jsheadercycleB5inlines.h
 186                -> tests/style/HeaderCycleB1-inl.h
 187       -> tests/style/HeaderCycleB4-inl.h
 188
 189 '''.splitlines(True)
 190
 191 actual_output = []
 192
 193
 194 def out(*lines):
 195     for line in lines:
 196         actual_output.append(line + '\n')
 197
 198
 199 def error(filename, linenum, *lines):
 200     location = filename
 201     if linenum is not None:
 202         location += ':' + str(linenum)
 203     out(location + ': error:')
 204     for line in (lines):
 205         out('    ' + line)
 206     out('')
 207
 208
 209 class FileKind(object):
 210     C = 1
 211     CPP = 2
 212     INL_H = 3
 213     H = 4
 214     TBL = 5
 215     MSG = 6
 216
 217     @staticmethod
 218     def get(filename):
 219         if filename.endswith('.c'):
 220             return FileKind.C
 221
 222         if filename.endswith('.cpp'):
 223             return FileKind.CPP
 224
 225         if filename.endswith(('inlines.h', '-inl.h')):
 226             return FileKind.INL_H
 227
 228         if filename.endswith('.h'):
 229             return FileKind.H
 230
 231         if filename.endswith('.tbl'):
 232             return FileKind.TBL
 233
 234         if filename.endswith('.msg'):
 235             return FileKind.MSG
 236
 237         error(filename, None, 'unknown file kind')
 238
 239
 240 def check_style(enable_fixup):
 241     # We deal with two kinds of name.
 242     # - A "filename" is a full path to a file from the repository root.
 243     # - An "inclname" is how a file is referred to in a #include statement.
 244     #
 245     # Examples (filename -> inclname)
 246     # - "mfbt/Attributes.h"         -> "mozilla/Attributes.h"
 247     # - "mfbt/decimal/Decimal.h     -> "mozilla/Decimal.h"
 248     # - "mozglue/misc/TimeStamp.h   -> "mozilla/TimeStamp.h"
 249     # - "memory/mozalloc/mozalloc.h -> "mozilla/mozalloc.h"
 250     # - "js/public/Vector.h"        -> "js/Vector.h"
 251     # - "js/src/vm/String.h"        -> "vm/String.h"
 252
 253     non_js_dirnames = ('mfbt/',
 254                        'memory/mozalloc/',
 255                        'mozglue/')  # type: tuple(str)
 256     non_js_inclnames = set()        # type: set(inclname)
 257     js_names = dict()               # type: dict(filename, inclname)
 258
 259     # Process files in js/src.
 260     js_src_root = os.path.join('js', 'src')
 261     for dirpath, dirnames, filenames in os.walk(js_src_root):
 262         if dirpath == js_src_root:
 263             # Skip any subdirectories that contain a config.status file
 264             # (likely objdirs).
 265             builddirs = []
 266             for dirname in dirnames:
 267                 path = os.path.join(dirpath, dirname, 'config.status')
 268                 if os.path.isfile(path):
 269                     builddirs.append(dirname)
 270             for dirname in builddirs:
 271                 dirnames.remove(dirname)
 272         for filename in filenames:
 273             filepath = os.path.join(dirpath, filename).replace('\\', '/')
 274             if not filepath.startswith(tuple(ignored_js_src_dirs)) and \
 275                filepath.endswith(('.c', '.cpp', '.h', '.tbl', '.msg')):
 276                 inclname = filepath[len('js/src/'):]
 277                 js_names[filepath] = inclname
 278
 279     # Look for header files in directories in non_js_dirnames.
 280     for non_js_dir in non_js_dirnames:
 281         for dirpath, dirnames, filenames in os.walk(non_js_dir):
 282             for filename in filenames:
 283                 if filename.endswith('.h'):
 284                     inclname = 'mozilla/' + filename
 285                     non_js_inclnames.add(inclname)
 286
 287     # Look for header files in js/public.
 288     js_public_root = os.path.join('js', 'public')
 289     for dirpath, dirnames, filenames in os.walk(js_public_root):
 290         for filename in filenames:
 291             if filename.endswith('.h'):
 292                 filepath = os.path.join(dirpath, filename).replace('\\', '/')
 293                 inclname = 'js/' + filepath[len('js/public/'):]
 294                 js_names[filepath] = inclname
 295
 296     all_inclnames = non_js_inclnames | set(js_names.values())
 297
 298     edges = dict()      # type: dict(inclname, set(inclname))
 299
 300     # We don't care what's inside the MFBT and MOZALLOC files, but because they
 301     # are #included from JS files we have to add them to the inclusion graph.
 302     for inclname in non_js_inclnames:
 303         edges[inclname] = set()
 304
 305     # Process all the JS files.
 306     for filename in js_names.keys():
 307         inclname = js_names[filename]
 308         file_kind = FileKind.get(filename)
 309         if file_kind == FileKind.C or file_kind == FileKind.CPP or \
 310            file_kind == FileKind.H or file_kind == FileKind.INL_H:
 311             included_h_inclnames = set()    # type: set(inclname)
 312
 313             with open(filename) as f:
 314                 code = read_file(f)
 315
 316             if enable_fixup:
 317                 code = code.sorted(inclname)
 318                 with open(filename, 'w') as f:
 319                     f.write(code.to_source())
 320
 321             check_file(filename, inclname, file_kind, code,
 322                        all_inclnames, included_h_inclnames)
 323
 324         edges[inclname] = included_h_inclnames
 325
 326     find_cycles(all_inclnames, edges)
 327
 328     # Compare expected and actual output.
 329     difflines = difflib.unified_diff(expected_output, actual_output,
 330                                      fromfile='check_spidermonkey_style.py expected output',
 331                                      tofile='check_spidermonkey_style.py actual output')
 332     ok = True
 333     for diffline in difflines:
 334         ok = False
 335         print(diffline, end='')
 336
 337     return ok
 338
 339
 340 def module_name(name):
 341     '''Strip the trailing .cpp, .h, inlines.h or -inl.h from a filename.'''
 342
 343     return name.replace('inlines.h', '').replace('-inl.h', '').replace('.h', '').replace('.cpp', '')  # NOQA: E501
 344
 345
 346 def is_module_header(enclosing_inclname, header_inclname):
 347     '''Determine if an included name is the "module header", i.e. should be
 348     first in the file.'''
 349
 350     module = module_name(enclosing_inclname)
 351
 352     # Normal case, e.g. module == "foo/Bar", header_inclname == "foo/Bar.h".
 353     if module == module_name(header_inclname):
 354         return True
 355
 356     # A public header, e.g. module == "foo/Bar", header_inclname == "js/Bar.h".
 357     m = re.match(r'js\/(.*)\.h', header_inclname)
 358     if m is not None and module.endswith('/' + m.group(1)):
 359         return True
 360
 361     return False
 362
 363
 364 class Include(object):
 365     '''Important information for a single #include statement.'''
 366
 367     def __init__(self, include_prefix, inclname, line_suffix, linenum, is_system):
 368         self.include_prefix = include_prefix
 369         self.line_suffix = line_suffix
 370         self.inclname = inclname
 371         self.linenum = linenum
 372         self.is_system = is_system
 373
 374     def is_style_relevant(self):
 375         # Includes are style-relevant; that is, they're checked by the pairwise
 376         # style-checking algorithm in check_file.
 377         return True
 378
 379     def section(self, enclosing_inclname):
 380         '''Identify which section inclname belongs to.
 381
 382         The section numbers are as follows.
 383           0. Module header (e.g. jsfoo.h or jsfooinlines.h within jsfoo.cpp)
 384           1. mozilla/Foo.h
 385           2. <foo.h> or <foo>
 386           3. jsfoo.h, prmjtime.h, etc
 387           4. foo/Bar.h
 388           5. jsfooinlines.h
 389           6. foo/Bar-inl.h
 390           7. non-.h, e.g. *.tbl, *.msg
 391         '''
 392
 393         if self.is_system:
 394             return 2
 395
 396         if not self.inclname.endswith('.h'):
 397             return 7
 398
 399         # A couple of modules have the .h file in js/ and the .cpp file elsewhere and so need
 400         # special handling.
 401         if is_module_header(enclosing_inclname, self.inclname):
 402             return 0
 403
 404         if '/' in self.inclname:
 405             if self.inclname.startswith('mozilla/'):
 406                 return 1
 407
 408             if self.inclname.endswith('-inl.h'):
 409                 return 6
 410
 411             return 4
 412
 413         if self.inclname.endswith('inlines.h'):
 414             return 5
 415
 416         return 3
 417
 418     def quote(self):
 419         if self.is_system:
 420             return '<' + self.inclname + '>'
 421         else:
 422             return '"' + self.inclname + '"'
 423
 424     def sort_key(self, enclosing_inclname):
 425         return (self.section(enclosing_inclname), self.inclname.lower())
 426
 427     def to_source(self):
 428         return self.include_prefix + self.quote() + self.line_suffix + '\n'
 429
 430
 431 class CppBlock(object):
 432     '''C preprocessor block: a whole file or a single #if/#elif/#else block.
 433
 434     A #if/#endif block is the contents of a #if/#endif (or similar) section.
 435     The top-level block, which is not within a #if/#endif pair, is also
 436     considered a block.
 437
 438     Each kid is either an Include (representing a #include), OrdinaryCode, or
 439     a nested CppBlock.'''
 440
 441     def __init__(self, start_line=""):
 442         self.start = start_line
 443         self.end = ''
 444         self.kids = []
 445
 446     def is_style_relevant(self):
 447         return True
 448
 449     def append_ordinary_line(self, line):
 450         if len(self.kids) == 0 or not isinstance(self.kids[-1], OrdinaryCode):
 451             self.kids.append(OrdinaryCode())
 452         self.kids[-1].lines.append(line)
 453
 454     def style_relevant_kids(self):
 455         """ Return a list of kids in this block that are style-relevant. """
 456         return [kid for kid in self.kids if kid.is_style_relevant()]
 457
 458     def sorted(self, enclosing_inclname):
 459         """Return a hopefully-sorted copy of this block. Implements --fixup.
 460
 461         When in doubt, this leaves the code unchanged.
 462         """
 463
 464         def pretty_sorted_includes(includes):
 465             """ Return a new list containing the given includes, in order,
 466             with blank lines separating sections. """
 467             keys = [inc.sort_key(enclosing_inclname) for inc in includes]
 468             if sorted(keys) == keys:
 469                 return includes  # if nothing is out of order, don't touch anything
 470
 471             output = []
 472             current_section = None
 473             for (section, _), inc in sorted(zip(keys, includes)):
 474                 if current_section is not None and section != current_section:
 475                     output.append(OrdinaryCode(["\n"]))  # blank line
 476                 output.append(inc)
 477                 current_section = section
 478             return output
 479
 480         def should_try_to_sort(includes):
 481             if 'tests/style/BadIncludes' in enclosing_inclname:
 482                 return False  # don't straighten the counterexample
 483             if any(inc.inclname in oddly_ordered_inclnames for inc in includes):
 484                 return False  # don't sort batches containing odd includes
 485             if includes == sorted(includes, key=lambda inc: inc.sort_key(enclosing_inclname)):
 486                 return False  # it's already sorted, avoid whitespace-only fixups
 487             return True
 488
 489         # The content of the eventual output of this method.
 490         output = []
 491
 492         # The current batch of includes to sort. This list only ever contains Include objects
 493         # and whitespace OrdinaryCode objects.
 494         batch = []
 495
 496         def flush_batch():
 497             """Sort the contents of `batch` and move it to `output`."""
 498
 499             assert all(isinstance(item, Include)
 500                        or (isinstance(item, OrdinaryCode) and "".join(item.lines).isspace())
 501                        for item in batch)
 502
 503             # Here we throw away the blank lines.
 504             # `pretty_sorted_includes` puts them back.
 505             includes = []
 506             last_include_index = -1
 507             for i, item in enumerate(batch):
 508                 if isinstance(item, Include):
 509                     includes.append(item)
 510                     last_include_index = i
 511             cutoff = last_include_index + 1
 512
 513             if should_try_to_sort(includes):
 514                 output.extend(pretty_sorted_includes(
 515                     includes) + batch[cutoff:])
 516             else:
 517                 output.extend(batch)
 518             del batch[:]
 519
 520         for kid in self.kids:
 521             if isinstance(kid, CppBlock):
 522                 flush_batch()
 523                 output.append(kid.sorted(enclosing_inclname))
 524             elif isinstance(kid, Include):
 525                 batch.append(kid)
 526             else:
 527                 assert isinstance(kid, OrdinaryCode)
 528                 if kid.to_source().isspace():
 529                     batch.append(kid)
 530                 else:
 531                     flush_batch()
 532                     output.append(kid)
 533         flush_batch()
 534
 535         result = CppBlock()
 536         result.start = self.start
 537         result.end = self.end
 538         result.kids = output
 539         return result
 540
 541     def to_source(self):
 542         return self.start + ''.join(kid.to_source() for kid in self.kids) + self.end
 543
 544
 545 class OrdinaryCode(object):
 546     ''' A list of lines of code that aren't #include/#if/#else/#endif lines. '''
 547
 548     def __init__(self, lines=None):
 549         self.lines = lines if lines is not None else []
 550
 551     def is_style_relevant(self):
 552         return False
 553
 554     def to_source(self):
 555         return ''.join(self.lines)
 556
 557
 558 # A "snippet" is one of:
 559 #
 560 # *   Include - representing an #include line
 561 # *   CppBlock - a whole file or #if/#elif/#else block; contains a list of snippets
 562 # *   OrdinaryCode - representing lines of non-#include-relevant code
 563
 564 def read_file(f):
 565     block_stack = [CppBlock()]
 566
 567     # Extract the #include statements as a tree of snippets.
 568     for linenum, line in enumerate(f, start=1):
 569         if line.lstrip().startswith('#'):
 570             # Look for a |#include "..."| line.
 571             m = re.match(r'(\s*#\s*include\s+)"([^"]*)"(.*)', line)
 572             if m is not None:
 573                 prefix, inclname, suffix = m.groups()
 574                 block_stack[-1].kids.append(Include(prefix,
 575                                                     inclname, suffix, linenum, is_system=False))
 576                 continue
 577
 578             # Look for a |#include <...>| line.
 579             m = re.match(r'(\s*#\s*include\s+)<([^>]*)>(.*)', line)
 580             if m is not None:
 581                 prefix, inclname, suffix = m.groups()
 582                 block_stack[-1].kids.append(Include(prefix,
 583                                                     inclname, suffix, linenum, is_system=True))
 584                 continue
 585
 586             # Look for a |#{if,ifdef,ifndef}| line.
 587             m = re.match(r'\s*#\s*(if|ifdef|ifndef)\b', line)
 588             if m is not None:
 589                 # Open a new block.
 590                 new_block = CppBlock(line)
 591                 block_stack[-1].kids.append(new_block)
 592                 block_stack.append(new_block)
 593                 continue
 594
 595             # Look for a |#{elif,else}| line.
 596             m = re.match(r'\s*#\s*(elif|else)\b', line)
 597             if m is not None:
 598                 # Close the current block, and open an adjacent one.
 599                 block_stack.pop()
 600                 new_block = CppBlock(line)
 601                 block_stack[-1].kids.append(new_block)
 602                 block_stack.append(new_block)
 603                 continue
 604
 605             # Look for a |#endif| line.
 606             m = re.match(r'\s*#\s*endif\b', line)
 607             if m is not None:
 608                 # Close the current block.
 609                 block_stack.pop().end = line
 610                 if len(block_stack) == 0:
 611                     raise ValueError(
 612                         "#endif without #if at line " + str(linenum))
 613                 continue
 614
 615         # Otherwise, we have an ordinary line.
 616         block_stack[-1].append_ordinary_line(line)
 617
 618     if len(block_stack) > 1:
 619         raise ValueError("unmatched #if")
 620     return block_stack[-1]
 621
 622
 623 def check_file(filename, inclname, file_kind, code, all_inclnames, included_h_inclnames):
 624
 625     def check_include_statement(include):
 626         '''Check the style of a single #include statement.'''
 627
 628         if include.is_system:
 629             # Check it is not a known local file (in which case it's probably a system header).
 630             if include.inclname in included_inclnames_to_ignore or \
 631                include.inclname in all_inclnames:
 632                 error(filename, include.linenum,
 633                       include.quote() + ' should be included using',
 634                       'the #include "..." form')
 635
 636         else:
 637             if include.inclname not in included_inclnames_to_ignore:
 638                 included_kind = FileKind.get(include.inclname)
 639
 640                 # Check the #include path has the correct form.
 641                 if include.inclname not in all_inclnames:
 642                     error(filename, include.linenum,
 643                           include.quote() + ' is included using the wrong path;',
 644                           'did you forget a prefix, or is the file not yet committed?')
 645
 646                 # Record inclusions of .h files for cycle detection later.
 647                 # (Exclude .tbl and .msg files.)
 648                 elif included_kind == FileKind.H or included_kind == FileKind.INL_H:
 649                     included_h_inclnames.add(include.inclname)
 650
 651                 # Check a H file doesn't #include an INL_H file.
 652                 if file_kind == FileKind.H and included_kind == FileKind.INL_H:
 653                     error(filename, include.linenum,
 654                           'vanilla header includes an inline-header file ' + include.quote())
 655
 656                 # Check a file doesn't #include itself.  (We do this here because the cycle
 657                 # detection below doesn't detect this case.)
 658                 if inclname == include.inclname:
 659                     error(filename, include.linenum,
 660                           'the file includes itself')
 661
 662     def check_includes_order(include1, include2):
 663         '''Check the ordering of two #include statements.'''
 664
 665         if include1.inclname in oddly_ordered_inclnames or \
 666            include2.inclname in oddly_ordered_inclnames:
 667             return
 668
 669         section1 = include1.section(inclname)
 670         section2 = include2.section(inclname)
 671         if (section1 > section2) or \
 672            ((section1 == section2) and (include1.inclname.lower() > include2.inclname.lower())):
 673             error(filename, str(include1.linenum) + ':' + str(include2.linenum),
 674                   include1.quote() + ' should be included after ' + include2.quote())
 675
 676     # Check the extracted #include statements, both individually, and the ordering of
 677     # adjacent pairs that live in the same block.
 678     def pair_traverse(prev, this):
 679         if isinstance(this, Include):
 680             check_include_statement(this)
 681             if isinstance(prev, Include):
 682                 check_includes_order(prev, this)
 683         else:
 684             kids = this.style_relevant_kids()
 685             for prev2, this2 in zip([None] + kids[0:-1], kids):
 686                 pair_traverse(prev2, this2)
 687
 688     pair_traverse(None, code)
 689
 690
 691 def find_cycles(all_inclnames, edges):
 692     '''Find and draw any cycles.'''
 693
 694     SCCs = tarjan(all_inclnames, edges)
 695
 696     # The various sorted() calls below ensure the output is deterministic.
 697
 698     def draw_SCC(c):
 699         cset = set(c)
 700         drawn = set()
 701
 702         def draw(v, indent):
 703             out('   ' * indent + ('-> ' if indent else '   ') + v)
 704             if v in drawn:
 705                 return
 706             drawn.add(v)
 707             for succ in sorted(edges[v]):
 708                 if succ in cset:
 709                     draw(succ, indent + 1)
 710         draw(sorted(c)[0], 0)
 711         out('')
 712
 713     have_drawn_an_SCC = False
 714     for scc in sorted(SCCs):
 715         if len(scc) != 1:
 716             if not have_drawn_an_SCC:
 717                 error('(multiple files)', None,
 718                       'header files form one or more cycles')
 719                 have_drawn_an_SCC = True
 720
 721             draw_SCC(scc)
 722
 723
 724 # Tarjan's algorithm for finding the strongly connected components (SCCs) of a graph.
 725 # https://en.wikipedia.org/wiki/Tarjan%27s_strongly_connected_components_algorithm
 726 def tarjan(V, E):
 727     vertex_index = {}
 728     vertex_lowlink = {}
 729     index = 0
 730     S = []
 731     all_SCCs = []
 732
 733     def strongconnect(v, index):
 734         # Set the depth index for v to the smallest unused index
 735         vertex_index[v] = index
 736         vertex_lowlink[v] = index
 737         index += 1
 738         S.append(v)
 739
 740         # Consider successors of v
 741         for w in E[v]:
 742             if w not in vertex_index:
 743                 # Successor w has not yet been visited; recurse on it
 744                 index = strongconnect(w, index)
 745                 vertex_lowlink[v] = min(vertex_lowlink[v], vertex_lowlink[w])
 746             elif w in S:
 747                 # Successor w is in stack S and hence in the current SCC
 748                 vertex_lowlink[v] = min(vertex_lowlink[v], vertex_index[w])
 749
 750         # If v is a root node, pop the stack and generate an SCC
 751         if vertex_lowlink[v] == vertex_index[v]:
 752             i = S.index(v)
 753             scc = S[i:]
 754             del S[i:]
 755             all_SCCs.append(scc)
 756
 757         return index
 758
 759     for v in V:
 760         if v not in vertex_index:
 761             index = strongconnect(v, index)
 762
 763     return all_SCCs
 764
 765
 766 def main():
 767     if sys.argv[1:] == ["--fixup"]:
 768         # Sort #include directives in-place.  Fixup mode doesn't solve
 769         # all possible silliness that the script checks for; it's just a
 770         # hack for the common case where renaming a header causes style
 771         # errors.
 772         fixup = True
 773     elif sys.argv[1:] == []:
 774         fixup = False
 775     else:
 776         print("TEST-UNEXPECTED-FAIL | check_spidermonkey_style.py | unexpected command "
 777               "line options: " + repr(sys.argv[1:]))
 778         sys.exit(1)
 779
 780     ok = check_style(fixup)
 781
 782     if ok:
 783         print('TEST-PASS | check_spidermonkey_style.py | ok')
 784     else:
 785         print('TEST-UNEXPECTED-FAIL | check_spidermonkey_style.py | ' +
 786               'actual output does not match expected output;  diff is above.')
 787         print('TEST-UNEXPECTED-FAIL | check_spidermonkey_style.py | ' +
 788               'Hint: If the problem is that you renamed a header, and many #includes ' +
 789               'are no longer in alphabetical order, commit your work and then try ' +
 790               '`check_spidermonkey_style.py --fixup`. ' +
 791               'You need to commit first because --fixup modifies your files in place.')
 792
 793     sys.exit(0 if ok else 1)
 794
 795
 796 if __name__ == '__main__':
 797     main()