Revert of Remove now obsolete checkdeps copy

tools/checkdeps/rules.py

+# Copyright 2012 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.
+
+"""Base classes to represent dependency rules, used by checkdeps.py"""
+
+
+import os
+import re
+
+
+class Rule(object):
+  """Specifies a single rule for an include, which can be one of
+  ALLOW, DISALLOW and TEMP_ALLOW.
+  """
+
+  # These are the prefixes used to indicate each type of rule. These
+  # are also used as values for self.allow to indicate which type of
+  # rule this is.
+  ALLOW = '+'
+  DISALLOW = '-'
+  TEMP_ALLOW = '!'
+
+  def __init__(self, allow, directory, dependent_directory, source):
+    self.allow = allow
+    self._dir = directory
+    self._dependent_dir = dependent_directory
+    self._source = source
+
+  def __str__(self):
+    return '"%s%s" from %s.' % (self.allow, self._dir, self._source)
+
+  def AsDependencyTuple(self):
+    """Returns a tuple (allow, dependent dir, dependee dir) for this rule,
+    which is fully self-sufficient to answer the question whether the dependent
+    is allowed to depend on the dependee, without knowing the external
+    context."""
+    return self.allow, self._dependent_dir or '.', self._dir or '.'
+
+  def ParentOrMatch(self, other):
+    """Returns true if the input string is an exact match or is a parent
+    of the current rule. For example, the input "foo" would match "foo/bar"."""
+    return self._dir == other or self._dir.startswith(other + '/')
+
+  def ChildOrMatch(self, other):
+    """Returns true if the input string would be covered by this rule. For
+    example, the input "foo/bar" would match the rule "foo"."""
+    return self._dir == other or other.startswith(self._dir + '/')
+
+
+class MessageRule(Rule):
+  """A rule that has a simple message as the reason for failing,
+  unrelated to directory or source.
+  """
+
+  def __init__(self, reason):
+    super(MessageRule, self).__init__(Rule.DISALLOW, '', '', '')
+    self._reason = reason
+
+  def __str__(self):
+    return self._reason
+
+
+def ParseRuleString(rule_string, source):
+  """Returns a tuple of a character indicating what type of rule this
+  is, and a string holding the path the rule applies to.
+  """
+  if not rule_string:
+    raise Exception('The rule string "%s" is empty\nin %s' %
+                    (rule_string, source))
+
+  if not rule_string[0] in [Rule.ALLOW, Rule.DISALLOW, Rule.TEMP_ALLOW]:
+    raise Exception(
+      'The rule string "%s" does not begin with a "+", "-" or "!".' %
+      rule_string)
+
+  return rule_string[0], rule_string[1:]
+
+
+class Rules(object):
+  """Sets of rules for files in a directory.
+
+  By default, rules are added to the set of rules applicable to all
+  dependee files in the directory.  Rules may also be added that apply
+  only to dependee files whose filename (last component of their path)
+  matches a given regular expression; hence there is one additional
+  set of rules per unique regular expression.
+  """
+
+  def __init__(self):
+    """Initializes the current rules with an empty rule list for all
+    files.
+    """
+    # We keep the general rules out of the specific rules dictionary,
+    # as we need to always process them last.
+    self._general_rules = []
+
+    # Keys are regular expression strings, values are arrays of rules
+    # that apply to dependee files whose basename matches the regular
+    # expression.  These are applied before the general rules, but
+    # their internal order is arbitrary.
+    self._specific_rules = {}
+
+  def __str__(self):
+    result = ['Rules = {\n    (apply to all files): [\n%s\n    ],' % '\n'.join(
+        '      %s' % x for x in self._general_rules)]
+    for regexp, rules in self._specific_rules.iteritems():
+      result.append('    (limited to files matching %s): [\n%s\n    ]' % (
+          regexp, '\n'.join('      %s' % x for x in rules)))
+    result.append('  }')
+    return '\n'.join(result)
+
+  def AsDependencyTuples(self, include_general_rules, include_specific_rules):
+    """Returns a list of tuples (allow, dependent dir, dependee dir) for the
+    specified rules (general/specific). Currently only general rules are
+    supported."""
+    def AddDependencyTuplesImpl(deps, rules, extra_dependent_suffix=""):
+      for rule in rules:
+        (allow, dependent, dependee) = rule.AsDependencyTuple()
+        tup = (allow, dependent + extra_dependent_suffix, dependee)
+        deps.add(tup)
+
+    deps = set()
+    if include_general_rules:
+      AddDependencyTuplesImpl(deps, self._general_rules)
+    if include_specific_rules:
+      for regexp, rules in self._specific_rules.iteritems():
+        AddDependencyTuplesImpl(deps, rules, "/" + regexp)
+    return deps
+
+  def AddRule(self, rule_string, dependent_dir, source, dependee_regexp=None):
+    """Adds a rule for the given rule string.
+
+    Args:
+      rule_string: The include_rule string read from the DEPS file to apply.
+      source: A string representing the location of that string (filename, etc.)
+              so that we can give meaningful errors.
+      dependent_dir: The directory to which this rule applies.
+      dependee_regexp: The rule will only be applied to dependee files
+                       whose filename (last component of their path)
+                       matches the expression. None to match all
+                       dependee files.
+    """
+    rule_type, rule_dir = ParseRuleString(rule_string, source)
+
+    if not dependee_regexp:
+      rules_to_update = self._general_rules
+    else:
+      if dependee_regexp in self._specific_rules:
+        rules_to_update = self._specific_rules[dependee_regexp]
+      else:
+        rules_to_update = []
+
+    # Remove any existing rules or sub-rules that apply. For example, if we're
+    # passed "foo", we should remove "foo", "foo/bar", but not "foobar".
+    rules_to_update = [x for x in rules_to_update
+                       if not x.ParentOrMatch(rule_dir)]
+    rules_to_update.insert(0, Rule(rule_type, rule_dir, dependent_dir, source))
+
+    if not dependee_regexp:
+      self._general_rules = rules_to_update
+    else:
+      self._specific_rules[dependee_regexp] = rules_to_update
+
+  def RuleApplyingTo(self, include_path, dependee_path):
+    """Returns the rule that applies to |include_path| for a dependee
+    file located at |dependee_path|.
+    """
+    dependee_filename = os.path.basename(dependee_path)
+    for regexp, specific_rules in self._specific_rules.iteritems():
+      if re.match(regexp, dependee_filename):
+        for rule in specific_rules:
+          if rule.ChildOrMatch(include_path):
+            return rule
+    for rule in self._general_rules:
+      if rule.ChildOrMatch(include_path):
+        return rule
+    return MessageRule('no rule applying.')