# Copyright (c) 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.

"""Top-level presubmit script for cc.

See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
for more details about the presubmit API built into depot_tools.
"""

import re
import string

CC_SOURCE_FILES=(r'^cc[\\/].*\.(cc|h)$',)

def CheckChangeLintsClean(input_api, output_api):
  source_filter = lambda x: input_api.FilterSourceFile(
    x, white_list=CC_SOURCE_FILES, black_list=None)

  return input_api.canned_checks.CheckChangeLintsClean(
      input_api, output_api, source_filter, lint_filters=[], verbose_level=1)

def CheckAsserts(input_api, output_api, white_list=CC_SOURCE_FILES, black_list=None):
  black_list = tuple(black_list or input_api.DEFAULT_BLACK_LIST)
  source_file_filter = lambda x: input_api.FilterSourceFile(x, white_list, black_list)

  assert_files = []

  for f in input_api.AffectedSourceFiles(source_file_filter):
    contents = input_api.ReadFile(f, 'rb')
    # WebKit ASSERT() is not allowed.
    if re.search(r"\bASSERT\(", contents):
      assert_files.append(f.LocalPath())

  if assert_files:
    return [output_api.PresubmitError(
      'These files use ASSERT instead of using DCHECK:',
      items=assert_files)]
  return []

def CheckStdAbs(input_api, output_api,
                white_list=CC_SOURCE_FILES, black_list=None):
  black_list = tuple(black_list or input_api.DEFAULT_BLACK_LIST)
  source_file_filter = lambda x: input_api.FilterSourceFile(x,
                                                            white_list,
                                                            black_list)

  using_std_abs_files = []
  found_fabs_files = []
  missing_std_prefix_files = []

  for f in input_api.AffectedSourceFiles(source_file_filter):
    contents = input_api.ReadFile(f, 'rb')
    if re.search(r"using std::f?abs;", contents):
      using_std_abs_files.append(f.LocalPath())
    if re.search(r"\bfabsf?\(", contents):
      found_fabs_files.append(f.LocalPath());

    no_std_prefix = r"(?<!std::)"
    # Matches occurrences of abs/absf/fabs/fabsf without a "std::" prefix.
    abs_without_prefix = r"%s(\babsf?\()" % no_std_prefix
    fabs_without_prefix = r"%s(\bfabsf?\()" % no_std_prefix
    # Skips matching any lines that have "// NOLINT".
    no_nolint = r"(?![^\n]*//\s+NOLINT)"

    expression = re.compile("(%s|%s)%s" %
        (abs_without_prefix, fabs_without_prefix, no_nolint))
    if expression.search(contents):
      missing_std_prefix_files.append(f.LocalPath())

  result = []
  if using_std_abs_files:
    result.append(output_api.PresubmitError(
        'These files have "using std::abs" which is not permitted.',
        items=using_std_abs_files))
  if found_fabs_files:
    result.append(output_api.PresubmitError(
        'std::abs() should be used instead of std::fabs() for consistency.',
        items=found_fabs_files))
  if missing_std_prefix_files:
    result.append(output_api.PresubmitError(
        'These files use abs(), absf(), fabs(), or fabsf() without qualifying '
        'the std namespace. Please use std::abs() in all places.',
        items=missing_std_prefix_files))
  return result

def CheckPassByValue(input_api,
                     output_api,
                     white_list=CC_SOURCE_FILES,
                     black_list=None):
  black_list = tuple(black_list or input_api.DEFAULT_BLACK_LIST)
  source_file_filter = lambda x: input_api.FilterSourceFile(x,
                                                            white_list,
                                                            black_list)

  local_errors = []

  # Well-defined simple classes the same size as a primitive type.
  pass_by_value_types = ['base::Time',
                         'base::TimeTicks',
                         ]

  for f in input_api.AffectedSourceFiles(source_file_filter):
    contents = input_api.ReadFile(f, 'rb')
    match = re.search(
      r'\bconst +' + '(?P<type>(%s))&' %
        string.join(pass_by_value_types, '|'),
      contents)
    if match:
      local_errors.append(output_api.PresubmitError(
        '%s passes %s by const ref instead of by value.' %
        (f.LocalPath(), match.group('type'))))
  return local_errors

def CheckTodos(input_api, output_api):
  errors = []

  source_file_filter = lambda x: x
  for f in input_api.AffectedSourceFiles(source_file_filter):
    contents = input_api.ReadFile(f, 'rb')
    if ('FIX'+'ME') in contents:
      errors.append(f.LocalPath())

  if errors:
    return [output_api.PresubmitError(
      'All TODO comments should be of the form TODO(name/bug). ' +
      'Use TODO instead of FIX' + 'ME',
      items=errors)]
  return []

def CheckDoubleAngles(input_api, output_api, white_list=CC_SOURCE_FILES,
                      black_list=None):
  errors = []

  source_file_filter = lambda x: input_api.FilterSourceFile(x,
                                                            white_list,
                                                            black_list)
  for f in input_api.AffectedSourceFiles(source_file_filter):
    contents = input_api.ReadFile(f, 'rb')
    if ('> >') in contents:
      errors.append(f.LocalPath())

  if errors:
    return [output_api.PresubmitError('Use >> instead of > >:', items=errors)]
  return []

def FindUnquotedQuote(contents, pos):
  match = re.search(r"(?<!\\)(?P<quote>\")", contents[pos:])
  return -1 if not match else match.start("quote") + pos

def FindUselessIfdefs(input_api, output_api):
  errors = []
  source_file_filter = lambda x: x
  for f in input_api.AffectedSourceFiles(source_file_filter):
    contents = input_api.ReadFile(f, 'rb')
    if re.search(r'#if\s*0\s', contents):
      errors.append(f.LocalPath())
  if errors:
    return [output_api.PresubmitError(
      'Don\'t use #if '+'0; just delete the code.',
      items=errors)]
  return []

def FindNamespaceInBlock(pos, namespace, contents, whitelist=[]):
  open_brace = -1
  close_brace = -1
  quote = -1
  name = -1
  brace_count = 1
  quote_count = 0
  while pos < len(contents) and brace_count > 0:
    if open_brace < pos: open_brace = contents.find("{", pos)
    if close_brace < pos: close_brace = contents.find("}", pos)
    if quote < pos: quote = FindUnquotedQuote(contents, pos)
    if name < pos: name = contents.find(("%s::" % namespace), pos)

    if name < 0:
      return False # The namespace is not used at all.
    if open_brace < 0:
      open_brace = len(contents)
    if close_brace < 0:
      close_brace = len(contents)
    if quote < 0:
      quote = len(contents)

    next = min(open_brace, min(close_brace, min(quote, name)))

    if next == open_brace:
      brace_count += 1
    elif next == close_brace:
      brace_count -= 1
    elif next == quote:
      quote_count = 0 if quote_count else 1
    elif next == name and not quote_count:
      in_whitelist = False
      for w in whitelist:
        if re.match(w, contents[next:]):
          in_whitelist = True
          break
      if not in_whitelist:
        return True
    pos = next + 1
  return False

# Checks for the use of cc:: within the cc namespace, which is usually
# redundant.
def CheckNamespace(input_api, output_api):
  errors = []

  source_file_filter = lambda x: x
  for f in input_api.AffectedSourceFiles(source_file_filter):
    contents = input_api.ReadFile(f, 'rb')
    match = re.search(r'namespace\s*cc\s*{', contents)
    if match:
      whitelist = []
      if FindNamespaceInBlock(match.end(), 'cc', contents, whitelist=whitelist):
        errors.append(f.LocalPath())

  if errors:
    return [output_api.PresubmitError(
      'Do not use cc:: inside of the cc namespace.',
      items=errors)]
  return []

def CheckForUseOfWrongClock(input_api,
                            output_api,
                            white_list=CC_SOURCE_FILES,
                            black_list=None):
  """Make sure new lines of code don't use a clock susceptible to skew."""
  black_list = tuple(black_list or input_api.DEFAULT_BLACK_LIST)
  source_file_filter = lambda x: input_api.FilterSourceFile(x,
                                                            white_list,
                                                            black_list)
  # Regular expression that should detect any explicit references to the
  # base::Time type (or base::Clock/DefaultClock), whether in using decls,
  # typedefs, or to call static methods.
  base_time_type_pattern = r'(^|\W)base::(Time|Clock|DefaultClock)(\W|$)'

  # Regular expression that should detect references to the base::Time class
  # members, such as a call to base::Time::Now.
  base_time_member_pattern = r'(^|\W)(Time|Clock|DefaultClock)::'

  # Regular expression to detect "using base::Time" declarations.  We want to
  # prevent these from triggerring a warning.  For example, it's perfectly
  # reasonable for code to be written like this:
  #
  #   using base::Time;
  #   ...
  #   int64 foo_us = foo_s * Time::kMicrosecondsPerSecond;
  using_base_time_decl_pattern = r'^\s*using\s+(::)?base::Time\s*;'

  # Regular expression to detect references to the kXXX constants in the
  # base::Time class.  We want to prevent these from triggerring a warning.
  base_time_konstant_pattern = r'(^|\W)Time::k\w+'

  problem_re = input_api.re.compile(
      r'(' + base_time_type_pattern + r')|(' + base_time_member_pattern + r')')
  exception_re = input_api.re.compile(
      r'(' + using_base_time_decl_pattern + r')|(' +
      base_time_konstant_pattern + r')')
  problems = []
  for f in input_api.AffectedSourceFiles(source_file_filter):
    for line_number, line in f.ChangedContents():
      if problem_re.search(line):
        if not exception_re.search(line):
          problems.append(
              '  %s:%d\n    %s' % (f.LocalPath(), line_number, line.strip()))

  if problems:
    return [output_api.PresubmitPromptOrNotify(
        'You added one or more references to the base::Time class and/or one\n'
        'of its member functions (or base::Clock/DefaultClock). In cc code,\n'
        'it is most certainly incorrect! Instead use base::TimeTicks.\n\n'
        '\n'.join(problems))]
  else:
    return []

def CheckChangeOnUpload(input_api, output_api):
  results = []
  results += CheckAsserts(input_api, output_api)
  results += CheckStdAbs(input_api, output_api)
  results += CheckPassByValue(input_api, output_api)
  results += CheckChangeLintsClean(input_api, output_api)
  results += CheckTodos(input_api, output_api)
  results += CheckDoubleAngles(input_api, output_api)
  results += CheckNamespace(input_api, output_api)
  results += CheckForUseOfWrongClock(input_api, output_api)
  results += FindUselessIfdefs(input_api, output_api)
  return results

def PostUploadHook(cl, change, output_api):
  """git cl upload will call this hook after the issue is created/modified.

  This hook adds an extra try bot list to the CL description in order to run
  Blink tests and additional GPU tests in addition to the CQ try bots.
  """
  return output_api.EnsureCQIncludeTrybotsAreAdded(
    cl,
    [
      'master.tryserver.blink:linux_trusty_blink_rel',
      'luci.chromium.try:android_optional_gpu_tests_rel',
    ],
    'Automatically added Blink and Android GPU trybots for CQ.')
