Add presubmit check and automatic update script for ExtensionPermission enum.

tools/strict_enum_value_checker/strict_enum_value_checker.py

-# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-"""Chromium presubmit script for src/chrome/browser/extensions.
+class StrictEnumValueChecker(object):
+  """Verify that changes to enums are valid.
 
-See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
-for more details on the presubmit API built into gcl.
-"""
-
-def GetPreferredTrySlaves():
-  return ['linux_chromeos']
-
-class HistogramValueChecker(object):
-  """Verify that changes to "extension_function_histogram_value.h" are valid.
-
-  See comments at the top of the "extension_function_histogram_value.h" file
-  for what are considered valid changes. There are situations where this script
-  gives false positive warnings, i.e. it warns even though the edit is
-  legitimate. Since the script warns using prompt warnings, the user can always
-  choose to continue. The main point is to attract the attention to all
-  (potentially or not) invalid edits.
+  This class is used to check enums where reordering or deletion is not allowed,
+  and additions must be at the end of the enum, just prior to some "boundary"
+  entry. See comments at the top of the "extension_function_histogram_value.h"
+  file in chrome/browser/extensions for an example what are considered valid
+  changes. There are situations where this class gives false positive warnings,
+  i.e. it warns even though the edit is legitimate. Since the class warns using
+  prompt warnings, the user can always choose to continue. The main point is to
+  attract the attention to all (potentially or not) invalid edits.
 
   """
-
-  # The name of the file we want to check against
-  LOCAL_PATH = "chrome/browser/extensions/extension_function_histogram_value.h"
-
-  # The markers we look for in the above source file as delimiters of the enum
-  # definition.
-  ENUM_START_MARKER = "enum HistogramValue {"
-  ENUM_END_MARKER = "  // Last entry:"
-
-  def __init__(self, input_api, output_api):
+  def __init__(self, input_api, output_api, start_marker, end_marker, path):
     self.input_api = input_api
     self.output_api = output_api
+    self.start_marker = start_marker
+    self.end_marker = end_marker
+    self.path = path
     self.results = []
 
   class EnumRange(object):
     """Represents a range of line numbers (1-based)"""
     def __init__(self, first_line, last_line):
       self.first_line = first_line
       self.last_line = last_line
 
     def Count(self):
       return self.last_line - self.first_line + 1
 
     def Contains(self, line_num):
       return self.first_line <= line_num and line_num <= self.last_line
 
   def LogInfo(self, message):
     self.input_api.logging.info(message)
     return
 
   def LogDebug(self, message):
     self.input_api.logging.debug(message)
     return
 
   def ComputeEnumRangeInContents(self, contents):
     """Returns an |EnumRange| object representing the line extent of the
-    HistogramValue enum members in |contents|. The line numbers are 1-based,
+    enum members in |contents|. The line numbers are 1-based,
     compatible with line numbers returned by AffectedFile.ChangeContents().
     |contents| is a list of strings reprenting the lines of a text file.
 
-    If either ENUM_START_MARKER or ENUM_END_MARKER cannot be found in
+    If either start_marker or end_marker cannot be found in
     |contents|, returns None and emits detailed warnings about the problem.
 
     """
     first_enum_line = 0
     last_enum_line = 0
     line_num = 1  # Line numbers are 1-based
     for line in contents:
-      if line.startswith(self.ENUM_START_MARKER):
+      if line.startswith(self.start_marker):
         first_enum_line = line_num + 1
-      elif line.startswith(self.ENUM_END_MARKER):
+      elif line.startswith(self.end_marker):
         last_enum_line = line_num
       line_num += 1
 
     if first_enum_line == 0:
       self.EmitWarning("The presubmit script could not find the start of the "
                        "enum definition (\"%s\"). Did the enum definition "
-                       "change?" % self.ENUM_START_MARKER)
+                       "change?" % self.start_marker)
       return None
 
     if last_enum_line == 0:
       self.EmitWarning("The presubmit script could not find the end of the "
                        "enum definition (\"%s\"). Did the enum definition "
-                       "change?" % self.ENUM_END_MARKER)
+                       "change?" % self.end_marker)
       return None
 
     if first_enum_line >= last_enum_line:
       self.EmitWarning("The presubmit script located the start of the enum "
                        "definition (\"%s\" at line %d) *after* its end "
                        "(\"%s\" at line %d). Something is not quite right."
-                       % (self.ENUM_START_MARKER, first_enum_line,
-                          self.ENUM_END_MARKER, last_enum_line))
+                       % (self.start_marker, first_enum_line,
+                          self.end_marker, last_enum_line))
       return None
 
-    self.LogInfo("Line extent of |HistogramValue| enum definition: "
+    self.LogInfo("Line extent of (\"%s\") enum definition: "
                  "first_line=%d, last_line=%d."
-                 % (first_enum_line, last_enum_line))
+                 % (self.start_marker, first_enum_line, last_enum_line))
     return self.EnumRange(first_enum_line, last_enum_line)
 
   def ComputeEnumRangeInNewFile(self, affected_file):
     return self.ComputeEnumRangeInContents(affected_file.NewContents())
 
-  def GetLongMessage(self):
+  def GetLongMessage(self, local_path):
     return str("The file \"%s\" contains the definition of the "
-               "|HistogramValue| enum which should be edited in specific ways "
+               "(\"%s\") enum which should be edited in specific ways "
                "only - *** read the comments at the top of the header file ***"
                ". There are changes to the file that may be incorrect and "
                "warrant manual confirmation after review. Note that this "
                "presubmit script can not reliably report the nature of all "
                "types of invalid changes, especially when the diffs are "
                "complex. For example, an invalid deletion may be reported "
                "whereas the change contains a valid rename."
-               % self.LOCAL_PATH)
+               % local_path, self.start_marker)
 
   def EmitWarning(self, message, line_number=None, line_text=None):
     """Emits a presubmit prompt warning containing the short message
     |message|. |item| is |LOCAL_PATH| with optional |line_number| and
     |line_text|.
 
     """
     if line_number is not None and line_text is not None:
-      item = "%s(%d): %s" % (self.LOCAL_PATH, line_number, line_text)
+      item = "%s(%d): %s" % (self.path, line_number, line_text)
     elif line_number is not None:
-      item = "%s(%d)" % (self.LOCAL_PATH, line_number)
+      item = "%s(%d)" % (self.path, line_number)
     else:
-      item = self.LOCAL_PATH
-    long_message = self.GetLongMessage()
+      item = self.path
+    long_message = self.GetLongMessage(self.path)
     self.LogInfo(message)
     self.results.append(
       self.output_api.PresubmitPromptWarning(message, [item], long_message))
 
   def CollectRangesInsideEnumDefinition(self, affected_file,
                                         first_line, last_line):
     """Returns a list of triplet (line_start, line_end, line_text) of ranges of
     edits changes. The |line_text| part is the text at line |line_start|.
     Since it used only for reporting purposes, we do not need all the text
     lines in the range.
@@ skipping 29 matching lines @@
     if previous_range_start_line_number != 0:
         addRange()
     return results
 
   def CheckForFileDeletion(self, affected_file):
     """Emits a warning notification if file has been deleted """
     if not affected_file.NewContents():
       self.EmitWarning("The file seems to be deleted in the changelist. If "
                        "your intent is to really delete the file, the code in "
                        "PRESUBMIT.py should be updated to remove the "
-                       "|HistogramValueChecker| class.");
+                       "|StrictEnumValueChecker| class.");
       return False
     return True
 
   def GetDeletedLinesFromScmDiff(self, affected_file):
     """Return a list of of line numbers (1-based) corresponding to lines
     deleted from the new source file (if they had been present in it). Note
     that if multiple contiguous lines have been deleted, the returned list will
     contain contiguous line number entries. To prevent false positives, we
     return deleted line numbers *only* from diff chunks which decrease the size
     of the new file.
 
     Note: We need this method because we have access to neither the old file
     content nor the list of "delete" changes from the current presubmit script
     API.
 
     """
     results = []
     line_num = 0
     deleting_lines = False
     for line in affected_file.GenerateScmDiff().splitlines():
       # Parse the unified diff chunk optional section heading, which looks like
       # @@ -l,s +l,s @@ optional section heading
       m = self.input_api.re.match(
-        r'^@@ \-([0-9]+)\,([0-9]+) \+([0-9]+)\,([0-9]+) @@', line)
+        r"^@@ \-([0-9]+)\,([0-9]+) \+([0-9]+)\,([0-9]+) @@", line)
       if m:
         old_line_num = int(m.group(1))
         old_size = int(m.group(2))
         new_line_num = int(m.group(3))
         new_size = int(m.group(4))
         line_num = new_line_num
         # Return line numbers only from diff chunks decreasing the size of the
         # new file
         deleting_lines = old_size > new_size
         continue
-      if not line.startswith('-'):
+      if not line.startswith("-"):
         line_num += 1
-      if deleting_lines and line.startswith('-') and not line.startswith('--'):
+      if deleting_lines and line.startswith("-") and not line.startswith("--"):
         results.append(line_num)
     return results
 
   def CheckForEnumEntryDeletions(self, affected_file):
     """Look for deletions inside the enum definition. We currently use a
     simple heuristics (not 100% accurate): if there are deleted lines inside
     the enum definition, this might be a deletion.
 
     """
     range_new = self.ComputeEnumRangeInNewFile(affected_file)
@@ skipping 32 matching lines @@
       is_valid_edit = (line_end == last_line - 1)
 
       self.LogDebug("Edit range in new file at starting at line number %d and "
                     "ending at line number %d: valid=%s"
                     % (line_start, line_end, is_valid_edit))
 
       if not is_valid_edit:
         self.EmitWarning("The change starting at line %d and ending at line "
                          "%d is *not* located *exactly* at the end of the "
                          "enum definition. Unless you are renaming an "
-                         "existing entry, this is not a valid changes, as new "
+                         "existing entry, this is not a valid change, as new "
                          "entries should *always* be added at the end of the "
-                         "enum definition, right before the 'ENUM_BOUNDARY' "
-                         "entry." % (line_start, line_end),
+                         "enum definition, right before the \"%s\" "
+                         "entry." % (line_start, line_end, self.end_marker),
                          line_start,
                          line_text)
         is_ok = False
     return is_ok
 
   def PerformChecks(self, affected_file):
     if not self.CheckForFileDeletion(affected_file):
       return
     if not self.CheckForEnumEntryDeletions(affected_file):
       return
     if not self.CheckForEnumEntryInsertions(affected_file):
       return
 
   def ProcessHistogramValueFile(self, affected_file):
     self.LogInfo("Start processing file \"%s\"" % affected_file.LocalPath())
     self.PerformChecks(affected_file)
     self.LogInfo("Done processing file \"%s\"" % affected_file.LocalPath())
 
   def Run(self):
     for file in self.input_api.AffectedFiles(include_deletes=True):
-      if file.LocalPath() == self.LOCAL_PATH:
+      if file.LocalPath() == self.path:
         self.ProcessHistogramValueFile(file)
     return self.results
-
-def CheckChangeOnUpload(input_api, output_api):
-  results = []
-  results += HistogramValueChecker(input_api, output_api).Run()
-  results += input_api.canned_checks.CheckPatchFormatted(input_api, output_api)
-  return results
-