chrome/browser/web_dev_style/js_checker.py

   1 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 """Presubmit script for Chromium JS resources.
   6
   7 See chrome/browser/PRESUBMIT.py
   8 """
   9
  10 import regex_check
  11
  12
  13 class JSChecker(object):
  14   def __init__(self, input_api, output_api, file_filter=None):
  15     self.input_api = input_api
  16     self.output_api = output_api
  17     self.file_filter = file_filter
  18
  19   def RegexCheck(self, line_number, line, regex, message):
  20     return regex_check.RegexCheck(
  21         self.input_api.re, line_number, line, regex, message)
  22
  23   def ChromeSendCheck(self, i, line):
  24     """Checks for a particular misuse of 'chrome.send'."""
  25     return self.RegexCheck(i, line, r"chrome\.send\('[^']+'\s*(, \[\])\)",
  26         'Passing an empty array to chrome.send is unnecessary')
  27
  28   def ConstCheck(self, i, line):
  29     """Check for use of the 'const' keyword."""
  30     if self.input_api.re.search(r'\*\s+@const', line):
  31       # Probably a JsDoc line
  32       return ''
  33
  34     return self.RegexCheck(i, line, r'(?:^|\s|\()(const)\s',
  35         'Use /** @const */ var varName; instead of const varName;')
  36
  37   def EndJsDocCommentCheck(self, i, line):
  38     msg = 'End JSDoc comments with */ instead of **/'
  39     def _check(regex):
  40       return self.RegexCheck(i, line, regex, msg)
  41     return _check(r'^\s*(\*\*/)\s*$') or _check(r'/\*\* @[a-zA-Z]+.* (\*\*/)')
  42
  43   def GetElementByIdCheck(self, i, line):
  44     """Checks for use of 'document.getElementById' instead of '$'."""
  45     return self.RegexCheck(i, line, r"(document\.getElementById)\('",
  46         "Use $('id'), from chrome://resources/js/util.js, instead of "
  47         "document.getElementById('id')")
  48
  49   def InheritDocCheck(self, i, line):
  50     """Checks for use of '@inheritDoc' instead of '@override'."""
  51     return self.RegexCheck(i, line, r"\* (@inheritDoc)",
  52         "@inheritDoc is deprecated, use @override instead")
  53
  54   def WrapperTypeCheck(self, i, line):
  55     """Check for wrappers (new String()) instead of builtins (string)."""
  56     return self.RegexCheck(i, line,
  57         r"(?:/\*)?\*.*?@(?:param|return|type) ?"     # /** @param/@return/@type
  58         r"{[^}]*\b(String|Boolean|Number)\b[^}]*}",  # {(Boolean|Number|String)}
  59         "Don't use wrapper types (i.e. new String() or @type {String})")
  60
  61   def VarNameCheck(self, i, line):
  62     """See the style guide. http://goo.gl/uKir6"""
  63     return self.RegexCheck(i, line,
  64         r"var (?!g_\w+)([a-z]*[_$][\w_$]*)(?<! \$)",
  65         "Please use var namesLikeThis <http://goo.gl/uKir6>")
  66
  67   def _GetErrorHighlight(self, start, length):
  68     """Takes a start position and a length, and produces a row of '^'s to
  69        highlight the corresponding part of a string.
  70     """
  71     return start * ' ' + length * '^'
  72
  73   def _MakeErrorOrWarning(self, error_text, filename):
  74     """Takes a few lines of text indicating a style violation and turns it into
  75        a PresubmitError (if |filename| is in a directory where we've already
  76        taken out all the style guide violations) or a PresubmitPromptWarning
  77        (if it's in a directory where we haven't done that yet).
  78     """
  79     # TODO(tbreisacher): Once we've cleaned up the style nits in all of
  80     # resources/ we can get rid of this function.
  81     path = self.input_api.os_path
  82     resources = path.join(self.input_api.PresubmitLocalPath(), 'resources')
  83     dirs = (
  84         path.join(resources, 'bookmark_manager'),
  85         path.join(resources, 'extensions'),
  86         path.join(resources, 'file_manager'),
  87         path.join(resources, 'help'),
  88         path.join(resources, 'history'),
  89         path.join(resources, 'memory_internals'),
  90         path.join(resources, 'net_export'),
  91         path.join(resources, 'net_internals'),
  92         path.join(resources, 'network_action_predictor'),
  93         path.join(resources, 'ntp4'),
  94         path.join(resources, 'options'),
  95         path.join(resources, 'password_manager_internals'),
  96         path.join(resources, 'print_preview'),
  97         path.join(resources, 'profiler'),
  98         path.join(resources, 'sync_promo'),
  99         path.join(resources, 'tracing'),
 100         path.join(resources, 'uber'),
 101     )
 102     if filename.startswith(dirs):
 103       return self.output_api.PresubmitError(error_text)
 104     else:
 105       return self.output_api.PresubmitPromptWarning(error_text)
 106
 107   def ClosureLint(self, file_to_lint, source=None):
 108     """Lints |file_to_lint| and returns the errors."""
 109
 110     import sys
 111     import warnings
 112     old_path = sys.path
 113     old_filters = warnings.filters
 114
 115     try:
 116       closure_linter_path = self.input_api.os_path.join(
 117           self.input_api.change.RepositoryRoot(),
 118           "third_party",
 119           "closure_linter")
 120       gflags_path = self.input_api.os_path.join(
 121           self.input_api.change.RepositoryRoot(),
 122           "third_party",
 123           "python_gflags")
 124
 125       sys.path.insert(0, closure_linter_path)
 126       sys.path.insert(0, gflags_path)
 127
 128       warnings.filterwarnings('ignore', category=DeprecationWarning)
 129
 130       from closure_linter import errors, runner
 131       from closure_linter.common import errorhandler
 132       import gflags
 133
 134     finally:
 135       sys.path = old_path
 136       warnings.filters = old_filters
 137
 138     class ErrorHandlerImpl(errorhandler.ErrorHandler):
 139       """Filters out errors that don't apply to Chromium JavaScript code."""
 140
 141       def __init__(self, re):
 142         self._errors = []
 143         self.re = re
 144
 145       def HandleFile(self, filename, first_token):
 146         self._filename = filename
 147
 148       def HandleError(self, error):
 149         if (self._valid(error)):
 150           error.filename = self._filename
 151           self._errors.append(error)
 152
 153       def GetErrors(self):
 154         return self._errors
 155
 156       def HasErrors(self):
 157         return bool(self._errors)
 158
 159       def _valid(self, error):
 160         """Check whether an error is valid. Most errors are valid, with a few
 161            exceptions which are listed here.
 162         """
 163
 164         is_grit_statement = bool(
 165             self.re.search("</?(include|if)", error.token.line))
 166
 167         # Ignore missing spaces before "(" until Promise#catch issue is solved.
 168         # http://crbug.com/338301
 169         if (error.code == errors.MISSING_SPACE and error.token.string == '(' and
 170            'catch(' in error.token.line):
 171           return False
 172
 173         # Ignore "}.bind(" errors. http://crbug.com/397697
 174         if (error.code == errors.MISSING_SEMICOLON_AFTER_FUNCTION and
 175             '}.bind(' in error.token.line):
 176           return False
 177
 178         return not is_grit_statement and error.code not in [
 179             errors.COMMA_AT_END_OF_LITERAL,
 180             errors.JSDOC_ILLEGAL_QUESTION_WITH_PIPE,
 181             errors.LINE_TOO_LONG,
 182             errors.MISSING_JSDOC_TAG_THIS,
 183         ]
 184
 185     # Whitelist Polymer-specific JsDoc tags.
 186     gflags.FLAGS.custom_jsdoc_tags = ('group', 'element', 'attribute',
 187                                       'default')
 188     error_handler = ErrorHandlerImpl(self.input_api.re)
 189     runner.Run(file_to_lint, error_handler, source=source)
 190     return error_handler.GetErrors()
 191
 192   def RunChecks(self):
 193     """Check for violations of the Chromium JavaScript style guide. See
 194        http://chromium.org/developers/web-development-style-guide#TOC-JavaScript
 195     """
 196     results = []
 197
 198     affected_files = self.input_api.change.AffectedFiles(
 199         file_filter=self.file_filter,
 200         include_deletes=False)
 201     affected_js_files = filter(lambda f: f.LocalPath().endswith('.js'),
 202                                affected_files)
 203     for f in affected_js_files:
 204       error_lines = []
 205
 206       # Check for the following:
 207       # * document.getElementById()
 208       # * the 'const' keyword
 209       # * Passing an empty array to 'chrome.send()'
 210       for i, line in enumerate(f.NewContents(), start=1):
 211         error_lines += filter(None, [
 212             self.ChromeSendCheck(i, line),
 213             self.ConstCheck(i, line),
 214             self.GetElementByIdCheck(i, line),
 215             self.InheritDocCheck(i, line),
 216             self.WrapperTypeCheck(i, line),
 217             self.VarNameCheck(i, line),
 218         ])
 219
 220       # Use closure linter to check for several different errors.
 221       lint_errors = self.ClosureLint(self.input_api.os_path.join(
 222           self.input_api.change.RepositoryRoot(), f.LocalPath()))
 223
 224       for error in lint_errors:
 225         highlight = self._GetErrorHighlight(
 226             error.token.start_index, error.token.length)
 227         error_msg = '  line %d: E%04d: %s\n%s\n%s' % (
 228             error.token.line_number,
 229             error.code,
 230             error.message,
 231             error.token.line.rstrip(),
 232             highlight)
 233         error_lines.append(error_msg)
 234
 235       if error_lines:
 236         error_lines = [
 237             'Found JavaScript style violations in %s:' %
 238             f.LocalPath()] + error_lines
 239         results.append(self._MakeErrorOrWarning(
 240             '\n'.join(error_lines), f.AbsoluteLocalPath()))
 241
 242     if results:
 243       results.append(self.output_api.PresubmitNotifyResult(
 244           'See the JavaScript style guide at '
 245           'http://www.chromium.org/developers/web-development-style-guide'
 246           '#TOC-JavaScript and if you have any feedback about the JavaScript '
 247           'PRESUBMIT check, contact tbreisacher@chromium.org or '
 248           'dbeam@chromium.org'))
 249
 250     return results