# Copyright (c) 2013 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 Blink.

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

import re
import sys


_EXCLUDED_PATHS = ()


def _CheckForVersionControlConflictsInFile(input_api, f):
    pattern = input_api.re.compile('^(?:<<<<<<<|>>>>>>>) |^=======$')
    errors = []
    for line_num, line in f.ChangedContents():
        if pattern.match(line):
            errors.append('    %s:%d %s' % (f.LocalPath(), line_num, line))
    return errors


def _CheckForVersionControlConflicts(input_api, output_api):
    """Usually this is not intentional and will cause a compile failure."""
    errors = []
    for f in input_api.AffectedFiles():
        errors.extend(_CheckForVersionControlConflictsInFile(input_api, f))

    results = []
    if errors:
        results.append(output_api.PresubmitError(
            'Version control conflict markers found, please resolve.', errors))
    return results


def _CheckWatchlist(input_api, output_api):
    """Check that the WATCHLIST file parses correctly."""
    errors = []
    for f in input_api.AffectedFiles():
        if f.LocalPath() != 'WATCHLISTS':
            continue
        import StringIO
        import logging
        import watchlists

        log_buffer = StringIO.StringIO()
        log_handler = logging.StreamHandler(log_buffer)
        log_handler.setFormatter(
            logging.Formatter('%(levelname)s: %(message)s'))
        logger = logging.getLogger()
        logger.addHandler(log_handler)

        wl = watchlists.Watchlists(input_api.change.RepositoryRoot())

        logger.removeHandler(log_handler)
        log_handler.flush()
        log_buffer.flush()

        if log_buffer.getvalue():
            errors.append(output_api.PresubmitError(
                'Cannot parse WATCHLISTS file, please resolve.',
                log_buffer.getvalue().splitlines()))
    return errors


def _CommonChecks(input_api, output_api):
    """Checks common to both upload and commit."""
    # We should figure out what license checks we actually want to use.
    license_header = r'.*'

    results = []
    results.extend(input_api.canned_checks.PanProjectChecks(
        input_api, output_api, excluded_paths=_EXCLUDED_PATHS,
        maxlen=800, license_header=license_header))
    results.extend(_CheckForVersionControlConflicts(input_api, output_api))
    results.extend(_CheckPatchFiles(input_api, output_api))
    results.extend(_CheckTestExpectations(input_api, output_api))
    results.extend(_CheckChromiumPlatformMacros(input_api, output_api))
    results.extend(_CheckWatchlist(input_api, output_api))
    results.extend(_CheckFilePermissions(input_api, output_api))
    return results


def _CheckPatchFiles(input_api, output_api):
  problems = [f.LocalPath() for f in input_api.AffectedFiles()
      if f.LocalPath().endswith(('.orig', '.rej'))]
  if problems:
    return [output_api.PresubmitError(
        "Don't commit .rej and .orig files.", problems)]
  else:
    return []


def _CheckTestExpectations(input_api, output_api):
    local_paths = [f.LocalPath() for f in input_api.AffectedFiles()]
    if any('LayoutTests' in path for path in local_paths):
        lint_path = input_api.os_path.join(input_api.PresubmitLocalPath(),
            'Tools', 'Scripts', 'lint-test-expectations')
        _, errs = input_api.subprocess.Popen(
            [input_api.python_executable, lint_path],
            stdout=input_api.subprocess.PIPE,
            stderr=input_api.subprocess.PIPE).communicate()
        if not errs:
            return [output_api.PresubmitError(
                "lint-test-expectations failed "
                "to produce output; check by hand. ")]
        if errs.strip() != 'Lint succeeded.':
            return [output_api.PresubmitError(errs)]
    return []


def _CheckStyle(input_api, output_api):
    # Files that follow Chromium's coding style do not include capital letters.
    re_chromium_style_file = re.compile(r'\b[a-z_]+\.(cc|h)$')
    style_checker_path = input_api.os_path.join(input_api.PresubmitLocalPath(),
        'Tools', 'Scripts', 'check-webkit-style')
    args = ([input_api.python_executable, style_checker_path, '--diff-files']
            + [input_api.os_path.join('..', '..', f.LocalPath())
               for f in input_api.AffectedFiles()
               # Filter out files that follow Chromium's coding style.
               if not re_chromium_style_file.search(f.LocalPath())])
    results = []

    try:
        child = input_api.subprocess.Popen(args,
                                           stderr=input_api.subprocess.PIPE)
        _, stderrdata = child.communicate()
        if child.returncode != 0:
            results.append(output_api.PresubmitError(
                'check-webkit-style failed', [stderrdata]))
    except Exception as e:
        results.append(output_api.PresubmitNotifyResult(
            'Could not run check-webkit-style', [str(e)]))

    return results


def _CheckChromiumPlatformMacros(input_api, output_api, source_file_filter=None):
    """Ensures that Blink code uses WTF's platform macros instead of
    Chromium's. Using the latter has resulted in at least one subtle
    build breakage."""
    os_macro_re = input_api.re.compile(r'^\s*#(el)?if.*\bOS_')
    errors = input_api.canned_checks._FindNewViolationsOfRule(
        lambda _, x: not os_macro_re.search(x),
        input_api, source_file_filter)
    errors = ['Found use of Chromium OS_* macro in %s. '
        'Use WTF platform macros instead.' % violation for violation in errors]
    if errors:
        return [output_api.PresubmitPromptWarning('\n'.join(errors))]
    return []


def _CheckForPrintfDebugging(input_api, output_api):
    """Generally speaking, we'd prefer not to land patches that printf
    debug output."""
    printf_re = input_api.re.compile(r'^\s*(printf\(|fprintf\(stderr,)')
    errors = input_api.canned_checks._FindNewViolationsOfRule(
        lambda _, x: not printf_re.search(x),
        input_api, None)
    errors = ['  * %s' % violation for violation in errors]
    if errors:
        return [output_api.PresubmitPromptOrNotify(
                    'printf debugging is best debugging! That said, it might '
                    'be a good idea to drop the following occurances from '
                    'your patch before uploading:\n%s' % '\n'.join(errors))]
    return []


def _CheckForDangerousTestFunctions(input_api, output_api):
    """Tests should not be using serveAsynchronousMockedRequests, since it does
    not guarantee that the threaded HTML parser will have completed."""
    serve_async_requests_re = input_api.re.compile(
        r'serveAsynchronousMockedRequests')
    errors = input_api.canned_checks._FindNewViolationsOfRule(
        lambda _, x: not serve_async_requests_re.search(x),
        input_api, None)
    errors = ['  * %s' % violation for violation in errors]
    if errors:
        return [output_api.PresubmitPromptOrNotify(
            'You should probably be using one of the FrameTestHelpers::'
            '(re)load* functions instead of '
            'serveAsynchronousMockedRequests() in the following '
            'locations:\n%s' % '\n'.join(errors))]
    return []


def _CheckForFailInFile(input_api, f):
    pattern = input_api.re.compile('^FAIL')
    errors = []
    for line_num, line in f.ChangedContents():
        if pattern.match(line):
            errors.append('    %s:%d %s' % (f.LocalPath(), line_num, line))
    return errors


def _CheckFilePermissions(input_api, output_api):
    """Check that all files have their permissions properly set."""
    if input_api.platform == 'win32':
        return []
    args = [input_api.python_executable,
            input_api.os_path.join(
                input_api.change.RepositoryRoot(),
                'tools/checkperms/checkperms.py'),
            '--root', input_api.change.RepositoryRoot()]
    for f in input_api.AffectedFiles():
        args += ['--file', f.LocalPath()]
    try:
        input_api.subprocess.check_output(args)
        return []
    except input_api.subprocess.CalledProcessError as error:
        return [output_api.PresubmitError(
            'checkperms.py failed:',
            long_text=error.output)]


def _CheckForInvalidPreferenceError(input_api, output_api):
    pattern = input_api.re.compile('Invalid name for preference: (.+)')
    results = []

    for f in input_api.AffectedFiles():
        if not f.LocalPath().endswith('-expected.txt'):
            continue
        for line_num, line in f.ChangedContents():
            error = pattern.search(line)
            if error:
                results.append(output_api.PresubmitError('Found an invalid preference %s in expected result %s:%s' % (error.group(1), f, line_num)))
    return results


def _CheckForForbiddenNamespace(input_api, output_api):
    """Checks that Blink uses Chromium namespaces only in permitted code."""
    # This list is not exhaustive, but covers likely ones.
    chromium_namespaces = ["base", "cc", "content", "gfx", "net", "ui"]
    chromium_classes = ["scoped_ptr", "scoped_refptr"]

    def source_file_filter(path):
        return input_api.FilterSourceFile(path,
                                          white_list=[r'third_party/WebKit/Source/.*\.(h|cpp)$'],
                                          black_list=[r'third_party/WebKit/Source/(platform|wtf|web)/'])

    comment_re = input_api.re.compile(r'^\s*//')
    result = []
    for namespace in chromium_namespaces:
        namespace_re = input_api.re.compile(r'\b{0}::|^\s*using namespace {0};|^\s*namespace {0} \{{'.format(input_api.re.escape(namespace)))
        uses_namespace_outside_comments = lambda line: namespace_re.search(line) and not comment_re.search(line)
        errors = input_api.canned_checks._FindNewViolationsOfRule(lambda _, line: not uses_namespace_outside_comments(line),
                                                                  input_api, source_file_filter)
        if errors:
            result += [output_api.PresubmitError('Do not use Chromium namespace {} inside Blink core:\n{}'.format(namespace, '\n'.join(errors)))]
    for class_name in chromium_classes:
        class_re = input_api.re.compile(r'\b{0}\b'.format(input_api.re.escape(class_name)))
        uses_class_outside_comments = lambda line: class_re.search(line) and not comment_re.search(line)
        errors = input_api.canned_checks._FindNewViolationsOfRule(lambda _, line: not uses_class_outside_comments(line),
                                                                  input_api, source_file_filter)
        if errors:
            result += [output_api.PresubmitError('Do not use Chromium class {} inside Blink core:\n{}'.format(class_name, '\n'.join(errors)))]
    return result


def CheckChangeOnUpload(input_api, output_api):
    results = []
    results.extend(_CommonChecks(input_api, output_api))
    results.extend(_CheckStyle(input_api, output_api))
    results.extend(_CheckForPrintfDebugging(input_api, output_api))
    results.extend(_CheckForDangerousTestFunctions(input_api, output_api))
    results.extend(_CheckForInvalidPreferenceError(input_api, output_api))
    results.extend(_CheckForForbiddenNamespace(input_api, output_api))
    return results


def CheckChangeOnCommit(input_api, output_api):
    results = []
    results.extend(_CommonChecks(input_api, output_api))
    results.extend(input_api.canned_checks.CheckTreeIsOpen(
        input_api, output_api,
        json_url='http://chromium-status.appspot.com/current?format=json'))
    results.extend(input_api.canned_checks.CheckChangeHasDescription(
        input_api, output_api))
    return results


def GetPreferredTryMasters(project, change):
    import json
    import os.path
    import platform
    import subprocess

    cq_config_path = os.path.join(
        change.RepositoryRoot(), 'infra', 'config', 'cq.cfg')
    # commit_queue.py below is a script in depot_tools directory, which has a
    # 'builders' command to retrieve a list of CQ builders from the CQ config.
    is_win = platform.system() == 'Windows'
    masters = json.loads(subprocess.check_output(
        ['commit_queue', 'builders', cq_config_path], shell=is_win))

    try_config = {}
    for master in masters:
        try_config.setdefault(master, {})
        for builder in masters[master]:
            # Do not trigger presubmit builders, since they're likely to fail
            # (e.g. OWNERS checks before finished code review), and we're
            # running local presubmit anyway.
            if 'presubmit' not in builder:
                try_config[master][builder] = ['defaulttests']

    return try_config