# Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
# for details. All rights reserved. Use of this source code is governed by a
# BSD-style license that can be found in the LICENSE file.

# This file contains a set of utilities functions used by other Python-based
# scripts.

from __future__ import print_function

import contextlib
import datetime
import glob
import imp
import json
import os
import platform
import re
import shutil
import subprocess
import sys
import tarfile
import tempfile
import uuid

try:
    # Not available on Windows.
    import resource
except:
    pass


# To eliminate clashing with older archived builds on bleeding edge we add
# a base number bigger the largest svn revision (this also gives us an easy
# way of seeing if an archive comes from git based or svn based commits).
GIT_NUMBER_BASE = 100000

# Mapping table between build mode and build configuration.
BUILD_MODES = {
    'debug': 'Debug',
    'release': 'Release',
    'product': 'Product',
}

# Mapping table between build mode and build configuration.
BUILD_SANITIZERS = {
    None: '',
    'none': '',
    'asan': 'ASAN',
    'lsan': 'LSAN',
    'msan': 'MSAN',
    'tsan': 'TSAN',
    'ubsan': 'UBSAN',
}

# Mapping table between OS and build output location.
BUILD_ROOT = {
    'win32': 'out',
    'linux': 'out',
    'freebsd': 'out',
    'macos': 'xcodebuild',
}

# Note: gn expects these to be lower case.
ARCH_FAMILY = {
    'ia32': 'ia32',
    'x64': 'ia32',
    'arm': 'arm',
    'armv6': 'arm',
    'arm64': 'arm',
    'arm_x64': 'arm',
    'simarm': 'ia32',
    'simarmv6': 'ia32',
    'simarm64': 'ia32',
    'simarm_x64': 'ia32',
}

BASE_DIR = os.path.abspath(os.path.join(os.curdir, '..'))
DART_DIR = os.path.abspath(os.path.join(__file__, '..', '..'))
VERSION_FILE = os.path.join(DART_DIR, 'tools', 'VERSION')


def GetArchFamily(arch):
    return ARCH_FAMILY[arch]


def GetBuildDir(host_os):
    return BUILD_ROOT[host_os]


def GetBuildMode(mode):
    return BUILD_MODES[mode]


def GetBuildSanitizer(sanitizer):
    return BUILD_SANITIZERS[sanitizer]


def GetBaseDir():
    return BASE_DIR


def GetBotUtils(repo_path=DART_DIR):
    '''Dynamically load the tools/bots/bot_utils.py python module.'''
    return imp.load_source(
        'bot_utils', os.path.join(repo_path, 'tools', 'bots', 'bot_utils.py'))


def GetMinidumpUtils(repo_path=DART_DIR):
    '''Dynamically load the tools/minidump.py python module.'''
    return imp.load_source('minidump',
                           os.path.join(repo_path, 'tools', 'minidump.py'))


class Version(object):

    def __init__(self, channel, major, minor, patch, prerelease,
                 prerelease_patch, abi_version, oldest_supported_abi_version):
        self.channel = channel
        self.major = major
        self.minor = minor
        self.patch = patch
        self.prerelease = prerelease
        self.prerelease_patch = prerelease_patch
        self.abi_version = abi_version
        self.oldest_supported_abi_version = oldest_supported_abi_version


# Try to guess the host operating system.
def GuessOS():
    os_id = platform.system()
    if os_id == 'Linux':
        return 'linux'
    elif os_id == 'Darwin':
        return 'macos'
    elif os_id == 'Windows' or os_id == 'Microsoft':
        # On Windows Vista platform.system() can return 'Microsoft' with some
        # versions of Python, see http://bugs.python.org/issue1082 for details.
        return 'win32'
    elif os_id == 'FreeBSD':
        return 'freebsd'
    elif os_id == 'OpenBSD':
        return 'openbsd'
    elif os_id == 'SunOS':
        return 'solaris'

    return None


# Try to guess the host architecture.
def GuessArchitecture():
    os_id = platform.machine()
    if os_id.startswith('armv6'):
        return 'armv6'
    elif os_id.startswith('arm'):
        return 'arm'
    elif os_id.startswith('aarch64'):
        return 'arm64'
    elif '64' in os_id:
        return 'x64'
    elif (not os_id) or (not re.match('(x|i[3-6])86', os_id) is None):
        return 'ia32'
    elif os_id == 'i86pc':
        return 'ia32'

    guess_os = GuessOS()
    print('Warning: Guessing architecture {} based on os {}\n'.format(
        os_id, guess_os))
    if guess_os == 'win32':
        return 'ia32'
    return None


# Try to guess the number of cpus on this machine.
def GuessCpus():
    if os.getenv('DART_NUMBER_OF_CORES') is not None:
        return int(os.getenv('DART_NUMBER_OF_CORES'))
    if os.path.exists('/proc/cpuinfo'):
        return int(
            subprocess.check_output(
                'grep -E \'^processor\' /proc/cpuinfo | wc -l', shell=True))
    if os.path.exists('/usr/bin/hostinfo'):
        return int(
            subprocess.check_output(
                '/usr/bin/hostinfo |'
                ' grep "processors are logically available." |'
                ' awk "{ print \$1 }"',
                shell=True))
    win_cpu_count = os.getenv("NUMBER_OF_PROCESSORS")
    if win_cpu_count:
        return int(win_cpu_count)
    return 2


def GetWindowsRegistryKeyName(name):
    import win32process
    # Check if python process is 64-bit or if it's 32-bit running in 64-bit OS.
    # We need to know whether host is 64-bit so that we are looking in right
    # registry for Visual Studio path.
    if sys.maxsize > 2**32 or win32process.IsWow64Process():
        wow6432Node = 'Wow6432Node\\'
    else:
        wow6432Node = ''
    return r'SOFTWARE\{}{}'.format(wow6432Node, name)


# Try to guess Visual Studio location when buiding on Windows.
def GuessVisualStudioPath():
    defaultPath = r'C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7' \
                  r'\IDE'
    defaultExecutable = 'devenv.com'

    if not IsWindows():
        return (defaultPath, defaultExecutable)

    keyNamesAndExecutables = [
        # Pair for non-Express editions.
        (GetWindowsRegistryKeyName(r'Microsoft\VisualStudio'), 'devenv.com'),
        # Pair for 2012 Express edition.
        (GetWindowsRegistryKeyName(r'Microsoft\VSWinExpress'),
         'VSWinExpress.exe'),
        # Pair for pre-2012 Express editions.
        (GetWindowsRegistryKeyName(r'Microsoft\VCExpress'), 'VCExpress.exe')
    ]

    bestGuess = (0.0, (defaultPath, defaultExecutable))

    import _winreg
    for (keyName, executable) in keyNamesAndExecutables:
        try:
            key = _winreg.OpenKey(_winreg.HKEY_LOCAL_MACHINE, keyName)
        except WindowsError:
            # Can't find this key - moving on the next one.
            continue

        try:
            subkeyCounter = 0
            while True:
                try:
                    subkeyName = _winreg.EnumKey(key, subkeyCounter)
                    subkeyCounter += 1
                except WindowsError:
                    # Reached end of enumeration. Moving on the next key.
                    break

                match = re.match(r'^\d+\.\d+$', subkeyName)
                if match:
                    with _winreg.OpenKey(key, subkeyName) as subkey:
                        try:
                            (installDir, registrytype) = _winreg.QueryValueEx(
                                subkey, 'InstallDir')
                        except WindowsError:
                            # Can't find value under the key - continue to the next key.
                            continue
                        isExpress = executable != 'devenv.com'
                        if not isExpress and subkeyName == '14.0':
                            # Stop search since if we found non-Express VS2015 version
                            # installed, which is preferred version.
                            return installDir, executable

                        version = float(subkeyName)
                        # We prefer higher version of Visual Studio and given equal
                        # version numbers we prefer non-Express edition.
                        if version > bestGuess[0]:
                            bestGuess = (version, (installDir, executable))
        finally:
            _winreg.CloseKey(key)
    return bestGuess[1]


# Returns true if we're running under Windows.
def IsWindows():
    return GuessOS() == 'win32'


# Reads a text file into an array of strings - one for each
# line. Strips comments in the process.
def ReadLinesFrom(name):
    result = []
    for line in open(name):
        if '#' in line:
            line = line[:line.find('#')]
        line = line.strip()
        if len(line) == 0:
            continue
        result.append(line)
    return result


# Filters out all arguments until the next '--' argument
# occurs.
def ListArgCallback(option, value, parser):
    if value is None:
        value = []

    for arg in parser.rargs:
        if arg[:2].startswith('--'):
            break
        value.append(arg)

    del parser.rargs[:len(value)]
    setattr(parser.values, option.dest, value)


# Filters out all argument until the first non '-' or the
# '--' argument occurs.
def ListDartArgCallback(option, value, parser):
    if value is None:
        value = []

    for arg in parser.rargs:
        if arg[:2].startswith('--') or arg[0] != '-':
            break
        value.append(arg)

    del parser.rargs[:len(value)]
    setattr(parser.values, option.dest, value)


def IsCrossBuild(target_os, arch):
    host_arch = GuessArchitecture()
    return ((GetArchFamily(host_arch) != GetArchFamily(arch)) or
            (target_os != GuessOS()))


def GetBuildConf(mode, arch, conf_os=None, sanitizer=None):
    if conf_os is not None and conf_os != GuessOS() and conf_os != 'host':
        return '{}{}{}'.format(GetBuildMode(mode), conf_os.title(),
                               arch.upper())

    # Ask for a cross build if the host and target architectures don't match.
    host_arch = GuessArchitecture()
    cross_build = ''
    if GetArchFamily(host_arch) != GetArchFamily(arch):
        cross_build = 'X'
    return '{}{}{}{}'.format(GetBuildMode(mode), GetBuildSanitizer(sanitizer),
                             cross_build, arch.upper())


def GetBuildRoot(host_os, mode=None, arch=None, target_os=None, sanitizer=None):
    build_root = GetBuildDir(host_os)
    if mode:
        build_root = os.path.join(
            build_root, GetBuildConf(mode, arch, target_os, sanitizer))
    return build_root


def GetBuildSdkBin(host_os, mode=None, arch=None, target_os=None):
    build_root = GetBuildRoot(host_os, mode, arch, target_os)
    return os.path.join(build_root, 'dart-sdk', 'bin')


def GetShortVersion(version_file=None):
    version = ReadVersionFile(version_file)
    return ('{}.{}.{}.{}.{}'.format(version.major, version.minor, version.patch,
                                    version.prerelease,
                                    version.prerelease_patch))


def GetSemanticSDKVersion(no_git_hash=False,
                          version_file=None,
                          git_revision_file=None):
    version = ReadVersionFile(version_file)
    if not version:
        return None

    suffix = ''
    if version.channel == 'be':
        suffix = '-edge' if no_git_hash else '-edge.{}'.format(
            GetGitRevision(git_revision_file))
    elif version.channel in ('beta', 'dev'):
        suffix = '-{}.{}.{}'.format(version.prerelease,
                                    version.prerelease_patch, version.channel)
    else:
        assert version.channel == 'stable'

    return '{}.{}.{}{}'.format(version.major, version.minor, version.patch,
                               suffix)


def GetVersion(no_git_hash=False, version_file=None, git_revision_file=None):
    return GetSemanticSDKVersion(no_git_hash, version_file, git_revision_file)


# The editor used to produce the VERSION file put on gcs. We now produce this
# in the bots archiving the sdk.
# The content looks like this:
#{
#  "date": "2015-05-28",
#  "version": "1.11.0-edge.131653",
#  "revision": "535394c2657ede445142d8a92486d3899bbf49b5"
#}
def GetVersionFileContent():
    result = {
        'date': str(datetime.date.today()),
        'version': GetVersion(),
        'revision': GetGitRevision()
    }
    return json.dumps(result, indent=2)


def GetChannel(version_file=None):
    version = ReadVersionFile(version_file)
    return version.channel


def GetUserName():
    key = 'USER'
    if sys.platform == 'win32':
        key = 'USERNAME'
    return os.environ.get(key, '')


def GetAbiVersion(version_file=None):
    version = ReadVersionFile(version_file)
    return version.abi_version


def GetOldestSupportedAbiVersion(version_file=None):
    version = ReadVersionFile(version_file)
    return version.oldest_supported_abi_version


def ReadVersionFile(version_file=None):

    def match_against(pattern, file_content):
        match = re.search(pattern, file_content, flags=re.MULTILINE)
        if match:
            return match.group(1)
        return None

    if version_file == None:
        version_file = VERSION_FILE

    content = None
    try:
        with open(version_file) as fd:
            content = fd.read()
    except:
        print('Warning: Could not read VERSION file ({})'.format(version_file))
        return None

    channel = match_against('^CHANNEL ([A-Za-z0-9]+)$', content)
    major = match_against('^MAJOR (\d+)$', content)
    minor = match_against('^MINOR (\d+)$', content)
    patch = match_against('^PATCH (\d+)$', content)
    prerelease = match_against('^PRERELEASE (\d+)$', content)
    prerelease_patch = match_against('^PRERELEASE_PATCH (\d+)$', content)
    abi_version = match_against('^ABI_VERSION (\d+)$', content)
    oldest_supported_abi_version = match_against(
        '^OLDEST_SUPPORTED_ABI_VERSION (\d+)$', content)

    if (channel and major and minor and prerelease and prerelease_patch and
            abi_version and oldest_supported_abi_version):
        return Version(channel, major, minor, patch, prerelease,
                       prerelease_patch, abi_version,
                       oldest_supported_abi_version)

    print('Warning: VERSION file ({}) has wrong format'.format(version_file))
    return None


# Our schema for releases and archiving is based on an increasing
# sequence of numbers. In the svn world this was simply the revision of a
# commit, which would always give us a one to one mapping between the number
# and the commit. This was true across branches as well, so a number used
# to archive a build was always unique and unambiguous.
# In git there is no such global number, so we loosen the requirement a bit.
# We only use numbers on the master branch (bleeding edge). On branches
# we use the version number instead for archiving purposes.
# The number on master is the count of commits on the master branch.
def GetArchiveVersion(version_file=None):
    version = ReadVersionFile(version_file=None)
    if not version:
        raise 'Could not get the archive version, parsing the version file failed'
    if version.channel in ['be', 'integration']:
        return GetGitNumber()
    return GetSemanticSDKVersion()


def GetGitRevision(git_revision_file=None, repo_path=DART_DIR):
    # When building from tarball use tools/GIT_REVISION
    if git_revision_file is None:
        git_revision_file = os.path.join(repo_path, 'tools', 'GIT_REVISION')
    try:
        with open(git_revision_file) as fd:
            return fd.read().decode('utf-8').strip()
    except:
        pass
    p = subprocess.Popen(['git', 'rev-parse', 'HEAD'],
                         stdout=subprocess.PIPE,
                         stderr=subprocess.STDOUT,
                         shell=IsWindows(),
                         cwd=repo_path)
    output, _ = p.communicate()
    revision = output.decode('utf-8').strip()
    # We expect a full git hash
    if len(revision) != 40:
        print('Warning: Could not parse git commit, output was {}'.format(
            revision),
              file=sys.stderr)
        return None
    return revision


def GetShortGitHash(repo_path=DART_DIR):
    p = subprocess.Popen(['git', 'rev-parse', '--short=10', 'HEAD'],
                         stdout=subprocess.PIPE,
                         stderr=subprocess.STDOUT,
                         shell=IsWindows(),
                         cwd=repo_path)
    output, _ = p.communicate()
    revision = output.decode('utf-8').strip()
    if p.wait() != 0:
        return None
    return revision


def GetLatestDevTag(repo_path=DART_DIR):
    # We used the old, pre-git2.13 refname:strip here since lstrip will fail on
    # older git versions. strip is an alias for lstrip in later versions.
    cmd = [
        'git',
        'for-each-ref',
        'refs/tags/*dev*',
        '--sort=-taggerdate',
        "--format=%(refname:strip=2)",
        '--count=1',
    ]
    p = subprocess.Popen(cmd,
                         stdout=subprocess.PIPE,
                         stderr=subprocess.STDOUT,
                         shell=IsWindows(),
                         cwd=repo_path)
    output, _ = p.communicate()
    tag = output.decode('utf-8').strip()
    if p.wait() != 0:
        print('Warning: Could not get the most recent dev branch tag {}'.format(
            tag),
              file=sys.stderr)
        return None
    return tag


def GetGitTimestamp(repo_path=DART_DIR):
    p = subprocess.Popen(['git', 'log', '-n', '1', '--pretty=format:%cd'],
                         stdout=subprocess.PIPE,
                         stderr=subprocess.STDOUT,
                         shell=IsWindows(),
                         cwd=repo_path)
    output, _ = p.communicate()
    timestamp = output.decode('utf-8').strip()
    if p.wait() != 0:
        return None
    return timestamp


def GetGitNumber(repo_path=DART_DIR):
    p = subprocess.Popen(['git', 'rev-list', 'HEAD', '--count'],
                         stdout=subprocess.PIPE,
                         stderr=subprocess.STDOUT,
                         shell=IsWindows(),
                         cwd=repo_path)
    output, _ = p.communicate()
    number = output.decode('utf-8').strip()
    try:
        number = int(number)
        return number + GIT_NUMBER_BASE
    except:
        print(
            'Warning: Could not parse git count, output was {}'.format(number),
            file=sys.stderr)
    return None


def ParseGitInfoOutput(output):
    """Given a git log, determine the latest corresponding svn revision."""
    for line in output.split('\n'):
        tokens = line.split()
        if len(tokens) > 0 and tokens[0] == 'git-svn-id:':
            return tokens[1].split('@')[1]
    return None


def ParseSvnInfoOutput(output):
    revision_match = re.search('Last Changed Rev: (\d+)', output)
    if revision_match:
        return revision_match.group(1)
    return None


def RewritePathSeparator(path, workspace):
    # Paths in test files are always specified using '/'
    # as the path separator. Replace with the actual
    # path separator before use.
    if '/' in path:
        split_path = path.split('/')
        path = os.sep.join(split_path)
        path = os.path.join(workspace, path)
        if not os.path.exists(path):
            raise Exception(path)
    return path


def ParseTestOptions(pattern, source, workspace):
    match = pattern.search(source)
    if match:
        return [
            RewritePathSeparator(o, workspace)
            for o in match.group(1).split(' ')
        ]
    return None


def ParseTestOptionsMultiple(pattern, source, workspace):
    matches = pattern.findall(source)
    if matches:
        result = []
        for match in matches:
            if len(match) > 0:
                result.append([
                    RewritePathSeparator(o, workspace) for o in match.split(' ')
                ])
            else:
                result.append([])
        return result
    return None


def Daemonize():
    """
    Create a detached background process (daemon). Returns True for
    the daemon, False for the parent process.
    See: http://www.faqs.org/faqs/unix-faq/programmer/faq/
    "1.7 How do I get my program to act like a daemon?"
    """
    if os.fork() > 0:
        return False
    os.setsid()
    if os.fork() > 0:
        exit(0)
        # TODO: What is this supposed to do? Didn't we already exit?
        raise
    return True


def CheckedUnlink(name):
    """Unlink a file without throwing an exception."""
    try:
        os.unlink(name)
    except OSError as e:
        sys.stderr.write('os.unlink() ' + str(e))
        sys.stderr.write('\n')


# TODO(42528): Can we remove this? It's basically just an alias for Exception.
class Error(Exception):
    pass


class ToolError(Exception):
    """Deprecated exception, use Error instead."""

    def __init__(self, value):
        self.value = value

    def __str__(self):
        return repr(self.value)


def IsCrashExitCode(exit_code):
    if IsWindows():
        return 0x80000000 & exit_code
    return exit_code < 0


def DiagnoseExitCode(exit_code, command):
    if IsCrashExitCode(exit_code):
        sys.stderr.write(
            'Command: {}\nCRASHED with exit code {} (0x{:x})\n'.format(
                ' '.join(command), exit_code, exit_code & 0xffffffff))


def Touch(name):
    with file(name, 'a'):
        os.utime(name, None)


def ExecuteCommand(cmd):
    """Execute a command in a subprocess."""
    print('Executing: ' + ' '.join(cmd))
    pipe = subprocess.Popen(cmd,
                            stdout=subprocess.PIPE,
                            stderr=subprocess.PIPE,
                            shell=IsWindows())
    output = pipe.communicate()
    if pipe.returncode != 0:
        raise Exception('Execution failed: ' + str(output))
    return pipe.returncode, output


# The checked-in SDKs are documented at
#     https://github.com/dart-lang/sdk/wiki/The-checked-in-SDK-in-tools
def CheckedInSdkPath():
    # We don't use the normal macos, linux, win32 directory names here, instead,
    # we use the names that the download_from_google_storage script uses.
    osdict = {'Darwin': 'mac', 'Linux': 'linux', 'Windows': 'win'}
    system = platform.system()
    try:
        osname = osdict[system]
    except KeyError:
        sys.stderr.write(
            'WARNING: platform "{}" not supported\n'.format(system))
        return None
    tools_dir = os.path.dirname(os.path.realpath(__file__))
    return os.path.join(tools_dir, 'sdks', 'dart-sdk')


def CheckedInSdkExecutable():
    name = 'dart'
    if IsWindows():
        name = 'dart.exe'
    return os.path.join(CheckedInSdkPath(), 'bin', name)


def CheckedInSdkCheckExecutable():
    executable = CheckedInSdkExecutable()
    canary_script = os.path.join(
        os.path.dirname(os.path.realpath(__file__)), 'canary.dart')
    try:
        with open(os.devnull, 'wb') as silent_sink:
            if 0 == subprocess.call([executable, canary_script],
                                    stdout=silent_sink):
                return True
    except OSError as e:
        pass
    return False


def CheckLinuxCoreDumpPattern(fatal=False):
    core_pattern_file = '/proc/sys/kernel/core_pattern'
    core_pattern = open(core_pattern_file).read()

    expected_core_pattern = 'core.%p'
    if core_pattern.strip() != expected_core_pattern:
        message = (
            'Invalid core_pattern configuration. '
            'The configuration of core dump handling is *not* correct for '
            'a buildbot. The content of {0} must be "{1}" instead of "{2}".'.
            format(core_pattern_file, expected_core_pattern, core_pattern))
        if fatal:
            raise Exception(message)
        print(message)
        return False
    return True


class TempDir(object):

    def __init__(self, prefix=''):
        self._temp_dir = None
        self._prefix = prefix

    def __enter__(self):
        self._temp_dir = tempfile.mkdtemp(self._prefix)
        return self._temp_dir

    def __exit__(self, *_):
        shutil.rmtree(self._temp_dir, ignore_errors=True)


class ChangedWorkingDirectory(object):

    def __init__(self, working_directory):
        self._working_directory = working_directory

    def __enter__(self):
        self._old_cwd = os.getcwd()
        print('Enter directory = ', self._working_directory)
        os.chdir(self._working_directory)

    def __exit__(self, *_):
        print('Enter directory = ', self._old_cwd)
        os.chdir(self._old_cwd)


class UnexpectedCrash(object):

    def __init__(self, test, pid, *binaries):
        self.test = test
        self.pid = pid
        self.binaries = binaries

    def __str__(self):
        return 'Crash({}: {} {})'.format(self.test, self.pid,
                                         ', '.join(self.binaries))


class PosixCoreDumpEnabler(object):

    def __init__(self):
        self._old_limits = None

    def __enter__(self):
        self._old_limits = resource.getrlimit(resource.RLIMIT_CORE)
        resource.setrlimit(resource.RLIMIT_CORE, (-1, -1))

    def __exit__(self, *_):
        if self._old_limits != None:
            resource.setrlimit(resource.RLIMIT_CORE, self._old_limits)


class LinuxCoreDumpEnabler(PosixCoreDumpEnabler):

    def __enter__(self):
        # Bump core limits to unlimited if core_pattern is correctly configured.
        if CheckLinuxCoreDumpPattern(fatal=False):
            super(LinuxCoreDumpEnabler, self).__enter__()

    def __exit__(self, *args):
        CheckLinuxCoreDumpPattern(fatal=False)
        super(LinuxCoreDumpEnabler, self).__exit__(*args)


class WindowsCoreDumpEnabler(object):
    """This enabler assumes that Dart binary was built with Crashpad support.
    In this case DART_CRASHPAD_CRASHES_DIR environment variable allows to
    specify the location of Crashpad crashes database. Actual minidumps will
    be written into reports subfolder of the database.
    """
    CRASHPAD_DB_FOLDER = os.path.join(DART_DIR, 'crashes')
    DUMPS_FOLDER = os.path.join(CRASHPAD_DB_FOLDER, 'reports')

    def __init__(self):
        pass

    def __enter__(self):
        print('INFO: Enabling coredump archiving into {}'.format(
            WindowsCoreDumpEnabler.CRASHPAD_DB_FOLDER))
        os.environ[
            'DART_CRASHPAD_CRASHES_DIR'] = WindowsCoreDumpEnabler.CRASHPAD_DB_FOLDER

    def __exit__(self, *_):
        del os.environ['DART_CRASHPAD_CRASHES_DIR']


def TryUnlink(file):
    try:
        os.unlink(file)
    except Exception as error:
        print('ERROR: Failed to remove {}: {}'.format(file, error))


class BaseCoreDumpArchiver(object):
    """This class reads coredumps file written by UnexpectedCrashDumpArchiver
    into the current working directory and uploads all cores and binaries
    listed in it into Cloud Storage (see
    pkg/test_runner/lib/src/test_progress.dart).
    """

    # test.dart will write a line for each unexpected crash into this file.
    _UNEXPECTED_CRASHES_FILE = 'unexpected-crashes'

    def __init__(self, search_dir, output_directory):
        self._bucket = 'dart-temp-crash-archive'
        self._binaries_dir = os.getcwd()
        self._search_dir = search_dir
        self._output_directory = output_directory

    def _safe_cleanup(self):
        try:
            return self._cleanup()
        except Exception as error:
            print('ERROR: Failure during cleanup: {}'.format(error))
            return False

    def __enter__(self):
        print('INFO: Core dump archiving is activated')

        # Cleanup any stale files
        if self._safe_cleanup():
            print('WARNING: Found and removed stale coredumps')

    def __exit__(self, *_):
        try:
            crashes = self._find_unexpected_crashes()
            if crashes:
                # If we get a ton of crashes, only archive 10 dumps.
                archive_crashes = crashes[:10]
                print('Archiving coredumps for crash (if possible):')
                for crash in archive_crashes:
                    print('----> {}'.format(crash))

                sys.stdout.flush()

                self._archive(archive_crashes)
            else:
                print('INFO: No unexpected crashes recorded')
                dumps = self._find_all_coredumps()
                if dumps:
                    print('INFO: However there are {} core dumps found'.format(
                        len(dumps)))
                    for dump in dumps:
                        print('INFO:        -> {}'.format(dump))
                    print()
        except Exception as error:
            print('ERROR: Failed to archive crashes: {}'.format(error))
            raise

        finally:
            self._safe_cleanup()

    def _archive(self, crashes):
        files = set()
        missing = []
        for crash in crashes:
            files.update(crash.binaries)
            core = self._find_coredump_file(crash)
            if core:
                files.add(core)
            else:
                missing.append(crash)
        if self._output_directory is not None and self._is_shard():
            print(
                "INFO: Moving collected dumps and binaries into output directory\n"
                "INFO: They will be uploaded to isolate server. Look for \"isolated"
                " out\" under the failed step on the build page.\n"
                "INFO: For more information see runtime/docs/infra/coredumps.md"
            )
            self._move(files)
        else:
            print(
                "INFO: Uploading collected dumps and binaries into Cloud Storage\n"
                "INFO: Use `gsutil.py cp from-url to-path` to download them.\n"
                "INFO: For more information see runtime/docs/infra/coredumps.md"
            )
            self._upload(files)

        if missing:
            self._report_missing_crashes(missing, throw=True)

    # todo(athom): move the logic to decide where to copy core dumps into the recipes.
    def _is_shard(self):
        return 'BUILDBOT_BUILDERNAME' not in os.environ

    def _report_missing_crashes(self, missing, throw=True):
        missing_as_string = ', '.join([str(c) for c in missing])
        other_files = list(glob.glob(os.path.join(self._search_dir, '*')))
        sys.stderr.write(
            "Could not find crash dumps for '{}' in search directory '{}'.\n"
            "Existing files which *did not* match the pattern inside the search "
            "directory are are:\n  {}\n".format(missing_as_string,
                                                self._search_dir,
                                                '\n  '.join(other_files)))
        # TODO: Figure out why windows coredump generation does not work.
        # See http://dartbug.com/36469
        if throw and GuessOS() != 'win32':
            raise Exception(
                'Missing crash dumps for: {}'.format(missing_as_string))

    def _get_file_name(self, file):
        # Sanitize the name: actual cores follow 'core.%d' pattern, crashed
        # binaries are copied next to cores and named
        # 'binary.<mode>_<arch>_<binary_name>'.
        # This should match the code in testing/dart/test_progress.dart
        name = os.path.basename(file)
        (prefix, suffix) = name.split('.', 1)
        is_binary = prefix == 'binary'
        if is_binary:
            (mode, arch, binary_name) = suffix.split('_', 2)
            name = binary_name
        return (name, is_binary)

    def _move(self, files):
        for file in files:
            print('+++ Moving {} to output_directory ({})'.format(
                file, self._output_directory))
            (name, is_binary) = self._get_file_name(file)
            destination = os.path.join(self._output_directory, name)
            shutil.move(file, destination)
            if is_binary and os.path.exists(file + '.pdb'):
                # Also move a PDB file if there is one.
                pdb = os.path.join(self._output_directory, name + '.pdb')
                shutil.move(file + '.pdb', pdb)

    def _tar(self, file):
        (name, is_binary) = self._get_file_name(file)
        tarname = '{}.tar.gz'.format(name)

        # Compress the file.
        tar = tarfile.open(tarname, mode='w:gz')
        tar.add(file, arcname=name)
        if is_binary and os.path.exists(file + '.pdb'):
            # Also add a PDB file if there is one.
            tar.add(file + '.pdb', arcname=name + '.pdb')
        tar.close()
        return tarname

    def _upload(self, files):
        bot_utils = GetBotUtils()
        gsutil = bot_utils.GSUtil()
        storage_path = '{}/{}/'.format(self._bucket, uuid.uuid4())
        gs_prefix = 'gs://{}'.format(storage_path)
        http_prefix = 'https://storage.cloud.google.com/{}'.format(storage_path)

        print('\n--- Uploading into {} ({}) ---'.format(gs_prefix, http_prefix))
        for file in files:
            tarname = self._tar(file)

            # Remove / from absolute path to not have // in gs path.
            gs_url = '{}{}'.format(gs_prefix, tarname)
            http_url = '{}{}'.format(http_prefix, tarname)

            try:
                gsutil.upload(tarname, gs_url)
                print('+++ Uploaded {} ({})'.format(gs_url, http_url))
            except Exception as error:
                print('!!! Failed to upload {}, error: {}'.format(
                    tarname, error))

            TryUnlink(tarname)

        print('--- Done ---\n')

    def _find_all_coredumps(self):
        """Return coredumps that were recorded (if supported by the platform).
        This method will be overriden by concrete platform specific implementations.
        """
        return []

    def _find_unexpected_crashes(self):
        """Load coredumps file. Each line has the following format:

        test-name,pid,binary-file1,binary-file2,...
        """
        try:
            with open(BaseCoreDumpArchiver._UNEXPECTED_CRASHES_FILE) as f:
                return [
                    UnexpectedCrash(*ln.strip('\n').split(','))
                    for ln in f.readlines()
                ]
        except:
            return []

    def _cleanup(self):
        found = False
        if os.path.exists(BaseCoreDumpArchiver._UNEXPECTED_CRASHES_FILE):
            os.unlink(BaseCoreDumpArchiver._UNEXPECTED_CRASHES_FILE)
            found = True
        for binary in glob.glob(os.path.join(self._binaries_dir, 'binary.*')):
            found = True
            TryUnlink(binary)

        return found


class PosixCoreDumpArchiver(BaseCoreDumpArchiver):

    def __init__(self, search_dir, output_directory):
        super(PosixCoreDumpArchiver, self).__init__(search_dir,
                                                    output_directory)

    def _cleanup(self):
        found = super(PosixCoreDumpArchiver, self)._cleanup()
        for core in glob.glob(os.path.join(self._search_dir, 'core.*')):
            found = True
            TryUnlink(core)
        return found

    def _find_coredump_file(self, crash):
        core_filename = os.path.join(self._search_dir,
                                     'core.{}'.format(crash.pid))
        if os.path.exists(core_filename):
            return core_filename


class LinuxCoreDumpArchiver(PosixCoreDumpArchiver):

    def __init__(self, output_directory):
        super(LinuxCoreDumpArchiver, self).__init__(os.getcwd(),
                                                    output_directory)


class MacOSCoreDumpArchiver(PosixCoreDumpArchiver):

    def __init__(self, output_directory):
        super(MacOSCoreDumpArchiver, self).__init__('/cores', output_directory)


class WindowsCoreDumpArchiver(BaseCoreDumpArchiver):

    def __init__(self, output_directory):
        super(WindowsCoreDumpArchiver, self).__init__(
            WindowsCoreDumpEnabler.DUMPS_FOLDER, output_directory)
        self._dumps_by_pid = None

    # Find CDB.exe in the win_toolchain that we are using.
    def _find_cdb(self):
        win_toolchain_json_path = os.path.join(DART_DIR, 'build',
                                               'win_toolchain.json')
        if not os.path.exists(win_toolchain_json_path):
            return None

        with open(win_toolchain_json_path, 'r') as f:
            win_toolchain_info = json.loads(f.read())

        win_sdk_path = win_toolchain_info['win_sdk']

        # We assume that we are running on 64-bit Windows.
        # Note: x64 CDB can work with both X64 and IA32 dumps.
        cdb_path = os.path.join(win_sdk_path, 'Debuggers', 'x64', 'cdb.exe')
        if not os.path.exists(cdb_path):
            return None

        return cdb_path

    CDBG_PROMPT_RE = re.compile(r'^\d+:\d+>')

    def _dump_all_stacks(self):
        # On Windows due to crashpad integration crashes do not produce any
        # stacktraces. Dump stack traces from dumps Crashpad collected using
        # CDB (if available).
        cdb_path = self._find_cdb()
        if cdb_path is None:
            return

        dumps = self._find_all_coredumps()
        if not dumps:
            return

        print('### Collected {} crash dumps'.format(len(dumps)))
        for dump in dumps:
            print()
            print('### Dumping stacks from {} using CDB'.format(dump))
            cdb_output = subprocess.check_output(
                '"{}" -z "{}" -kqm -c "!uniqstack -b -v -p;qd"'.format(
                    cdb_path, dump),
                stderr=subprocess.STDOUT)
            # Extract output of uniqstack from the whole output of CDB.
            output = False
            for line in cdb_output.split('\n'):
                if re.match(WindowsCoreDumpArchiver.CDBG_PROMPT_RE, line):
                    output = True
                elif line.startswith('quit:'):
                    break
                elif output:
                    print(line)
        print()
        print('#############################################')
        print()

    def __exit__(self, *args):
        try:
            self._dump_all_stacks()
        except Exception as error:
            print('ERROR: Unable to dump stacks from dumps: {}'.format(error))

        super(WindowsCoreDumpArchiver, self).__exit__(*args)

    def _cleanup(self):
        found = super(WindowsCoreDumpArchiver, self)._cleanup()
        for core in glob.glob(os.path.join(self._search_dir, '*')):
            found = True
            TryUnlink(core)
        return found

    def _find_all_coredumps(self):
        pattern = os.path.join(self._search_dir, '*.dmp')
        return [core_filename for core_filename in glob.glob(pattern)]

    def _find_coredump_file(self, crash):
        if self._dumps_by_pid is None:
            # If this function is invoked the first time then look through the directory
            # that contains crashes for all dump files and collect pid -> filename
            # mapping.
            self._dumps_by_pid = {}
            minidump = GetMinidumpUtils()
            pattern = os.path.join(self._search_dir, '*.dmp')
            for core_filename in glob.glob(pattern):
                pid = minidump.GetProcessIdFromDump(core_filename)
                if pid != -1:
                    self._dumps_by_pid[str(pid)] = core_filename
        if crash.pid in self._dumps_by_pid:
            return self._dumps_by_pid[crash.pid]

    def _report_missing_crashes(self, missing, throw=True):
        # Let's only print the debugging information and not throw. We'll do more
        # validation for werfault.exe and throw afterwards.
        super(WindowsCoreDumpArchiver, self)._report_missing_crashes(
            missing, throw=False)

        if throw:
            missing_as_string = ', '.join([str(c) for c in missing])
            raise Exception(
                'Missing crash dumps for: {}'.format(missing_as_string))


class IncreasedNumberOfFileDescriptors(object):

    def __init__(self, nofiles):
        self._old_limits = None
        self._limits = (nofiles, nofiles)

    def __enter__(self):
        self._old_limits = resource.getrlimit(resource.RLIMIT_NOFILE)
        resource.setrlimit(resource.RLIMIT_NOFILE, self._limits)

    def __exit__(self, *_):
        resource.setrlimit(resource.RLIMIT_CORE, self._old_limits)


@contextlib.contextmanager
def NooptContextManager():
    yield


def CoreDumpArchiver(args):
    enabled = '--copy-coredumps' in args
    prefix = '--output-directory='
    output_directory = next(
        (arg[len(prefix):] for arg in args if arg.startswith(prefix)), None)

    if not enabled:
        return NooptContextManager()

    osname = GuessOS()
    if osname == 'linux':
        return contextlib.nested(LinuxCoreDumpEnabler(),
                                 LinuxCoreDumpArchiver(output_directory))
    elif osname == 'macos':
        return contextlib.nested(PosixCoreDumpEnabler(),
                                 MacOSCoreDumpArchiver(output_directory))
    elif osname == 'win32':
        return contextlib.nested(WindowsCoreDumpEnabler(),
                                 WindowsCoreDumpArchiver(output_directory))

    # We don't have support for MacOS yet.
    return NooptContextManager()


def FileDescriptorLimitIncreaser():
    osname = GuessOS()
    if osname == 'macos':
        return IncreasedNumberOfFileDescriptors(nofiles=10000)

    assert osname in ('linux', 'win32')
    # We don't have support for MacOS yet.
    return NooptContextManager()


def Main():
    print('GuessOS() -> ', GuessOS())
    print('GuessArchitecture() -> ', GuessArchitecture())
    print('GuessCpus() -> ', GuessCpus())
    print('IsWindows() -> ', IsWindows())
    print('GuessVisualStudioPath() -> ', GuessVisualStudioPath())
    print('GetGitRevision() -> ', GetGitRevision())
    print('GetGitTimestamp() -> ', GetGitTimestamp())
    print('GetVersionFileContent() -> ', GetVersionFileContent())
    print('GetGitNumber() -> ', GetGitNumber())


if __name__ == '__main__':
    Main()