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