meson/mesonbuild/mesonlib.py

# Copyright 2012-2015 The Meson development team

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at

#     http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""A library of random helper functionality."""

import sys
import stat
import time
import platform, subprocess, operator, os, shutil, re
import collections
from mesonbuild import mlog

have_fcntl = False
have_msvcrt = False

try:
    import fcntl
    have_fcntl = True
except Exception:
    pass

try:
    import msvcrt
    have_msvcrt = True
except Exception:
    pass

from glob import glob

def detect_meson_py_location():
    c = sys.argv[0]
    c_dir, c_fname = os.path.split(c)

    # get the absolute path to the <mesontool> folder
    m_dir = None
    if os.path.isabs(c):
        # $ /foo/<mesontool>.py <args>
        m_dir = c_dir
    elif c_dir == '':
        # $ <mesontool> <args> (gets run from /usr/bin/<mesontool>)
        in_path_exe = shutil.which(c_fname)
        if in_path_exe:
            if not os.path.isabs(in_path_exe):
                m_dir = os.getcwd()
                c_fname = in_path_exe
            else:
                m_dir, c_fname = os.path.split(in_path_exe)
    else:
        m_dir = os.path.abspath(c_dir)

    # find meson in m_dir
    if m_dir is not None:
        for fname in ['meson', 'meson.py']:
            m_path = os.path.join(m_dir, fname)
            if os.path.exists(m_path):
                return m_path

    # No meson found, which means that either:
    # a) meson is not installed
    # b) meson is installed to a non-standard location
    # c) the script that invoked mesonlib is not the one of meson tools (e.g. run_unittests.py)
    fname = os.path.normpath(os.path.join(os.path.dirname(__file__), '..', 'meson.py'))
    if os.path.exists(fname):
        return fname
    # If meson is still not found, we might be imported by out-of-source tests
    # https://github.com/mesonbuild/meson/issues/3015
    exe = shutil.which('meson')
    if exe is None:
        exe = shutil.which('meson.py')
    if exe is not None:
        return exe
    # Give up.
    raise RuntimeError('Could not determine how to run Meson. Please file a bug with details.')

if os.path.basename(sys.executable) == 'meson.exe':
    # In Windows and using the MSI installed executable.
    meson_command = [sys.executable]
    python_command = [sys.executable, 'runpython']
else:
    python_command = [sys.executable]
    meson_command = python_command + [detect_meson_py_location()]

def is_ascii_string(astring):
    try:
        if isinstance(astring, str):
            astring.encode('ascii')
        if isinstance(astring, bytes):
            astring.decode('ascii')
    except UnicodeDecodeError:
        return False
    return True

def check_direntry_issues(direntry_array):
    import locale
    # Warn if the locale is not UTF-8. This can cause various unfixable issues
    # such as os.stat not being able to decode filenames with unicode in them.
    # There is no way to reset both the preferred encoding and the filesystem
    # encoding, so we can just warn about it.
    e = locale.getpreferredencoding()
    if e.upper() != 'UTF-8' and not is_windows():
        if not isinstance(direntry_array, list):
            direntry_array = [direntry_array]
        for de in direntry_array:
            if is_ascii_string(de):
                continue
            mlog.warning('''You are using {!r} which is not a Unicode-compatible '
locale but you are trying to access a file system entry called {!r} which is
not pure ASCII. This may cause problems.
'''.format(e, de), file=sys.stderr)

# Put this in objects that should not get dumped to pickle files
# by accident.
import threading
an_unpicklable_object = threading.Lock()

class MesonException(Exception):
    '''Exceptions thrown by Meson'''

class EnvironmentException(MesonException):
    '''Exceptions thrown while processing and creating the build environment'''

class FileMode:
    # The first triad is for owner permissions, the second for group permissions,
    # and the third for others (everyone else).
    # For the 1st character:
    #  'r' means can read
    #  '-' means not allowed
    # For the 2nd character:
    #  'w' means can write
    #  '-' means not allowed
    # For the 3rd character:
    #  'x' means can execute
    #  's' means can execute and setuid/setgid is set (owner/group triads only)
    #  'S' means cannot execute and setuid/setgid is set (owner/group triads only)
    #  't' means can execute and sticky bit is set ("others" triads only)
    #  'T' means cannot execute and sticky bit is set ("others" triads only)
    #  '-' means none of these are allowed
    #
    # The meanings of 'rwx' perms is not obvious for directories; see:
    # https://www.hackinglinuxexposed.com/articles/20030424.html
    #
    # For information on this notation such as setuid/setgid/sticky bits, see:
    # https://en.wikipedia.org/wiki/File_system_permissions#Symbolic_notation
    symbolic_perms_regex = re.compile('[r-][w-][xsS-]' # Owner perms
                                      '[r-][w-][xsS-]' # Group perms
                                      '[r-][w-][xtT-]') # Others perms

    def __init__(self, perms=None, owner=None, group=None):
        self.perms_s = perms
        self.perms = self.perms_s_to_bits(perms)
        self.owner = owner
        self.group = group

    def __repr__(self):
        ret = '<FileMode: {!r} owner={} group={}'
        return ret.format(self.perms_s, self.owner, self.group)

    @classmethod
    def perms_s_to_bits(cls, perms_s):
        '''
        Does the opposite of stat.filemode(), converts strings of the form
        'rwxr-xr-x' to st_mode enums which can be passed to os.chmod()
        '''
        if perms_s is None:
            # No perms specified, we will not touch the permissions
            return -1
        eg = 'rwxr-xr-x'
        if not isinstance(perms_s, str):
            msg = 'Install perms must be a string. For example, {!r}'
            raise MesonException(msg.format(eg))
        if len(perms_s) != 9 or not cls.symbolic_perms_regex.match(perms_s):
            msg = 'File perms {!r} must be exactly 9 chars. For example, {!r}'
            raise MesonException(msg.format(perms_s, eg))
        perms = 0
        # Owner perms
        if perms_s[0] == 'r':
            perms |= stat.S_IRUSR
        if perms_s[1] == 'w':
            perms |= stat.S_IWUSR
        if perms_s[2] == 'x':
            perms |= stat.S_IXUSR
        elif perms_s[2] == 'S':
            perms |= stat.S_ISUID
        elif perms_s[2] == 's':
            perms |= stat.S_IXUSR
            perms |= stat.S_ISUID
        # Group perms
        if perms_s[3] == 'r':
            perms |= stat.S_IRGRP
        if perms_s[4] == 'w':
            perms |= stat.S_IWGRP
        if perms_s[5] == 'x':
            perms |= stat.S_IXGRP
        elif perms_s[5] == 'S':
            perms |= stat.S_ISGID
        elif perms_s[5] == 's':
            perms |= stat.S_IXGRP
            perms |= stat.S_ISGID
        # Others perms
        if perms_s[6] == 'r':
            perms |= stat.S_IROTH
        if perms_s[7] == 'w':
            perms |= stat.S_IWOTH
        if perms_s[8] == 'x':
            perms |= stat.S_IXOTH
        elif perms_s[8] == 'T':
            perms |= stat.S_ISVTX
        elif perms_s[8] == 't':
            perms |= stat.S_IXOTH
            perms |= stat.S_ISVTX
        return perms

class File:
    def __init__(self, is_built, subdir, fname):
        self.is_built = is_built
        self.subdir = subdir
        self.fname = fname
        assert(isinstance(self.subdir, str))
        assert(isinstance(self.fname, str))

    def __str__(self):
        return self.relative_name()

    def __repr__(self):
        ret = '<File: {0}'
        if not self.is_built:
            ret += ' (not built)'
        ret += '>'
        return ret.format(self.relative_name())

    @staticmethod
    def from_source_file(source_root, subdir, fname):
        if not os.path.isfile(os.path.join(source_root, subdir, fname)):
            raise MesonException('File %s does not exist.' % fname)
        return File(False, subdir, fname)

    @staticmethod
    def from_built_file(subdir, fname):
        return File(True, subdir, fname)

    @staticmethod
    def from_absolute_file(fname):
        return File(False, '', fname)

    def rel_to_builddir(self, build_to_src):
        if self.is_built:
            return self.relative_name()
        else:
            return os.path.join(build_to_src, self.subdir, self.fname)

    def absolute_path(self, srcdir, builddir):
        absdir = srcdir
        if self.is_built:
            absdir = builddir
        return os.path.join(absdir, self.relative_name())

    def endswith(self, ending):
        return self.fname.endswith(ending)

    def split(self, s):
        return self.fname.split(s)

    def __eq__(self, other):
        return (self.fname, self.subdir, self.is_built) == (other.fname, other.subdir, other.is_built)

    def __hash__(self):
        return hash((self.fname, self.subdir, self.is_built))

    def relative_name(self):
        return os.path.join(self.subdir, self.fname)

def get_compiler_for_source(compilers, src):
    for comp in compilers:
        if comp.can_compile(src):
            return comp
    raise RuntimeError('No specified compiler can handle file {!s}'.format(src))

def classify_unity_sources(compilers, sources):
    compsrclist = {}
    for src in sources:
        comp = get_compiler_for_source(compilers, src)
        if comp not in compsrclist:
            compsrclist[comp] = [src]
        else:
            compsrclist[comp].append(src)
    return compsrclist

def is_osx():
    return platform.system().lower() == 'darwin'

def is_linux():
    return platform.system().lower() == 'linux'

def is_android():
    return platform.system().lower() == 'android'

def is_haiku():
    return platform.system().lower() == 'haiku'

def is_windows():
    platname = platform.system().lower()
    return platname == 'windows' or 'mingw' in platname

def is_cygwin():
    platname = platform.system().lower()
    return platname.startswith('cygwin')

def is_debianlike():
    return os.path.isfile('/etc/debian_version')

def is_dragonflybsd():
    return platform.system().lower() == 'dragonfly'

def is_freebsd():
    return platform.system().lower() == 'freebsd'

def for_windows(is_cross, env):
    """
    Host machine is windows?

    Note: 'host' is the machine on which compiled binaries will run
    """
    if not is_cross:
        return is_windows()
    elif env.cross_info.has_host():
        return env.cross_info.config['host_machine']['system'] == 'windows'
    return False

def for_cygwin(is_cross, env):
    """
    Host machine is cygwin?

    Note: 'host' is the machine on which compiled binaries will run
    """
    if not is_cross:
        return is_cygwin()
    elif env.cross_info.has_host():
        return env.cross_info.config['host_machine']['system'] == 'cygwin'
    return False

def for_linux(is_cross, env):
    """
    Host machine is linux?

    Note: 'host' is the machine on which compiled binaries will run
    """
    if not is_cross:
        return is_linux()
    elif env.cross_info.has_host():
        return env.cross_info.config['host_machine']['system'] == 'linux'
    return False

def for_darwin(is_cross, env):
    """
    Host machine is Darwin (iOS/OS X)?

    Note: 'host' is the machine on which compiled binaries will run
    """
    if not is_cross:
        return is_osx()
    elif env.cross_info.has_host():
        return env.cross_info.config['host_machine']['system'] == 'darwin'
    return False

def for_android(is_cross, env):
    """
    Host machine is Android?

    Note: 'host' is the machine on which compiled binaries will run
    """
    if not is_cross:
        return is_android()
    elif env.cross_info.has_host():
        return env.cross_info.config['host_machine']['system'] == 'android'
    return False

def for_haiku(is_cross, env):
    """
    Host machine is Haiku?

    Note: 'host' is the machine on which compiled binaries will run
    """
    if not is_cross:
        return is_haiku()
    elif env.cross_info.has_host():
        return env.cross_info.config['host_machine']['system'] == 'haiku'
    return False

def exe_exists(arglist):
    try:
        p = subprocess.Popen(arglist, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        p.communicate()
        if p.returncode == 0:
            return True
    except FileNotFoundError:
        pass
    return False

def detect_vcs(source_dir):
    vcs_systems = [
        dict(name = 'git',        cmd = 'git', repo_dir = '.git', get_rev = 'git describe --dirty=+', rev_regex = '(.*)', dep = '.git/logs/HEAD'),
        dict(name = 'mercurial',  cmd = 'hg',  repo_dir = '.hg',  get_rev = 'hg id -i',               rev_regex = '(.*)', dep = '.hg/dirstate'),
        dict(name = 'subversion', cmd = 'svn', repo_dir = '.svn', get_rev = 'svn info',               rev_regex = 'Revision: (.*)', dep = '.svn/wc.db'),
        dict(name = 'bazaar',     cmd = 'bzr', repo_dir = '.bzr', get_rev = 'bzr revno',              rev_regex = '(.*)', dep = '.bzr'),
    ]

    segs = source_dir.replace('\\', '/').split('/')
    for i in range(len(segs), -1, -1):
        curdir = '/'.join(segs[:i])
        for vcs in vcs_systems:
            if os.path.isdir(os.path.join(curdir, vcs['repo_dir'])) and shutil.which(vcs['cmd']):
                vcs['wc_dir'] = curdir
                return vcs
    return None

def grab_leading_numbers(vstr, strict=False):
    result = []
    for x in vstr.rstrip('.').split('.'):
        try:
            result.append(int(x))
        except ValueError as e:
            if strict:
                msg = 'Invalid version to compare against: {!r}; only ' \
                      'numeric digits separated by "." are allowed: ' + str(e)
                raise MesonException(msg.format(vstr))
            break
    return result

numpart = re.compile('[0-9.]+')

def version_compare(vstr1, vstr2, strict=False):
    match = numpart.match(vstr1.strip())
    if match is None:
        msg = 'Uncomparable version string {!r}.'
        raise MesonException(msg.format(vstr1))
    vstr1 = match.group(0)
    if vstr2.startswith('>='):
        cmpop = operator.ge
        vstr2 = vstr2[2:]
    elif vstr2.startswith('<='):
        cmpop = operator.le
        vstr2 = vstr2[2:]
    elif vstr2.startswith('!='):
        cmpop = operator.ne
        vstr2 = vstr2[2:]
    elif vstr2.startswith('=='):
        cmpop = operator.eq
        vstr2 = vstr2[2:]
    elif vstr2.startswith('='):
        cmpop = operator.eq
        vstr2 = vstr2[1:]
    elif vstr2.startswith('>'):
        cmpop = operator.gt
        vstr2 = vstr2[1:]
    elif vstr2.startswith('<'):
        cmpop = operator.lt
        vstr2 = vstr2[1:]
    else:
        cmpop = operator.eq
    varr1 = grab_leading_numbers(vstr1, strict)
    varr2 = grab_leading_numbers(vstr2, strict)
    return cmpop(varr1, varr2)

def version_compare_many(vstr1, conditions):
    if not isinstance(conditions, (list, tuple, frozenset)):
        conditions = [conditions]
    found = []
    not_found = []
    for req in conditions:
        if not version_compare(vstr1, req, strict=True):
            not_found.append(req)
        else:
            found.append(req)
    return not_found == [], not_found, found

def default_libdir():
    if is_debianlike():
        try:
            pc = subprocess.Popen(['dpkg-architecture', '-qDEB_HOST_MULTIARCH'],
                                  stdout=subprocess.PIPE,
                                  stderr=subprocess.DEVNULL)
            (stdo, _) = pc.communicate()
            if pc.returncode == 0:
                archpath = stdo.decode().strip()
                return 'lib/' + archpath
        except Exception:
            pass
    if os.path.isdir('/usr/lib64') and not os.path.islink('/usr/lib64'):
        return 'lib64'
    return 'lib'

def default_libexecdir():
    # There is no way to auto-detect this, so it must be set at build time
    return 'libexec'

def default_prefix():
    return 'c:/' if is_windows() else '/usr/local'

def get_library_dirs():
    if is_windows():
        return ['C:/mingw/lib'] # Fixme
    if is_osx():
        return ['/usr/lib'] # Fix me as well.
    # The following is probably Debian/Ubuntu specific.
    # /usr/local/lib is first because it contains stuff
    # installed by the sysadmin and is probably more up-to-date
    # than /usr/lib. If you feel that this search order is
    # problematic, please raise the issue on the mailing list.
    unixdirs = ['/usr/local/lib', '/usr/lib', '/lib']
    plat = subprocess.check_output(['uname', '-m']).decode().strip()
    # This is a terrible hack. I admit it and I'm really sorry.
    # I just don't know what the correct solution is.
    if plat == 'i686':
        plat = 'i386'
    if plat.startswith('arm'):
        plat = 'arm'
    unixdirs += glob('/usr/lib/' + plat + '*')
    if os.path.exists('/usr/lib64'):
        unixdirs.append('/usr/lib64')
    unixdirs += glob('/lib/' + plat + '*')
    if os.path.exists('/lib64'):
        unixdirs.append('/lib64')
    unixdirs += glob('/lib/' + plat + '*')
    return unixdirs

def has_path_sep(name, sep='/\\'):
    'Checks if any of the specified @sep path separators are in @name'
    for each in sep:
        if each in name:
            return True
    return False

def do_replacement(regex, line, format, confdata):
    missing_variables = set()
    start_tag = '@'
    backslash_tag = '\\@'
    if format == 'cmake':
        start_tag = '${'
        backslash_tag = '\\${'

    def variable_replace(match):
        # Pairs of escape characters before '@' or '\@'
        if match.group(0).endswith('\\'):
            num_escapes = match.end(0) - match.start(0)
            return '\\' * (num_escapes // 2)
        # Single escape character and '@'
        elif match.group(0) == backslash_tag:
            return start_tag
        # Template variable to be replaced
        else:
            varname = match.group(1)
            if varname in confdata:
                (var, desc) = confdata.get(varname)
                if isinstance(var, str):
                    pass
                elif isinstance(var, int):
                    var = str(var)
                else:
                    raise RuntimeError('Tried to replace a variable with something other than a string or int.')
            else:
                missing_variables.add(varname)
                var = ''
            return var
    return re.sub(regex, variable_replace, line), missing_variables

def do_mesondefine(line, confdata):
    arr = line.split()
    if len(arr) != 2:
        raise MesonException('#mesondefine does not contain exactly two tokens: %s', line.strip())
    varname = arr[1]
    try:
        (v, desc) = confdata.get(varname)
    except KeyError:
        return '/* #undef %s */\n' % varname
    if isinstance(v, bool):
        if v:
            return '#define %s\n' % varname
        else:
            return '#undef %s\n' % varname
    elif isinstance(v, int):
        return '#define %s %d\n' % (varname, v)
    elif isinstance(v, str):
        return '#define %s %s\n' % (varname, v)
    else:
        raise MesonException('#mesondefine argument "%s" is of unknown type.' % varname)


def do_conf_file(src, dst, confdata, format):
    try:
        with open(src, encoding='utf-8') as f:
            data = f.readlines()
    except Exception as e:
        raise MesonException('Could not read input file %s: %s' % (src, str(e)))
    # Only allow (a-z, A-Z, 0-9, _, -) as valid characters for a define
    # Also allow escaping '@' with '\@'
    if format in ['meson', 'cmake@']:
        regex = re.compile(r'(?:\\\\)+(?=\\?@)|\\@|@([-a-zA-Z0-9_]+)@')
    elif format == 'cmake':
        regex = re.compile(r'(?:\\\\)+(?=\\?\$)|\\\${|\${([-a-zA-Z0-9_]+)}')
    else:
        raise MesonException('Format "{}" not handled'.format(format))

    search_token = '#mesondefine'
    if format != 'meson':
        search_token = '#cmakedefine'

    result = []
    missing_variables = set()
    for line in data:
        if line.startswith(search_token):
            line = do_mesondefine(line, confdata)
        else:
            line, missing = do_replacement(regex, line, format, confdata)
            missing_variables.update(missing)
        result.append(line)
    dst_tmp = dst + '~'
    with open(dst_tmp, 'w', encoding='utf-8') as f:
        f.writelines(result)
    shutil.copymode(src, dst_tmp)
    replace_if_different(dst, dst_tmp)
    return missing_variables

def dump_conf_header(ofilename, cdata):
    ofilename_tmp = ofilename + '~'
    with open(ofilename_tmp, 'w', encoding='utf-8') as ofile:
        ofile.write('''/*
 * Autogenerated by the Meson build system.
 * Do not edit, your changes will be lost.
 */

#pragma once

''')
        for k in sorted(cdata.keys()):
            (v, desc) = cdata.get(k)
            if desc:
                ofile.write('/* %s */\n' % desc)
            if isinstance(v, bool):
                if v:
                    ofile.write('#define %s\n\n' % k)
                else:
                    ofile.write('#undef %s\n\n' % k)
            elif isinstance(v, (int, str)):
                ofile.write('#define %s %s\n\n' % (k, v))
            else:
                raise MesonException('Unknown data type in configuration file entry: ' + k)
    replace_if_different(ofilename, ofilename_tmp)

def replace_if_different(dst, dst_tmp):
    # If contents are identical, don't touch the file to prevent
    # unnecessary rebuilds.
    different = True
    try:
        with open(dst, 'rb') as f1, open(dst_tmp, 'rb') as f2:
            if f1.read() == f2.read():
                different = False
    except FileNotFoundError:
        pass
    if different:
        os.replace(dst_tmp, dst)
    else:
        os.unlink(dst_tmp)

def listify(item, flatten=True, unholder=False):
    '''
    Returns a list with all args embedded in a list if they are not a list.
    This function preserves order.
    @flatten: Convert lists of lists to a flat list
    @unholder: Replace each item with the object it holds, if required

    Note: unholding only works recursively when flattening
    '''
    if not isinstance(item, list):
        if unholder and hasattr(item, 'held_object'):
            item = item.held_object
        return [item]
    result = []
    for i in item:
        if unholder and hasattr(i, 'held_object'):
            i = i.held_object
        if flatten and isinstance(i, list):
            result += listify(i, flatten=True, unholder=unholder)
        else:
            result.append(i)
    return result


def extract_as_list(dict_object, *keys, pop=False, **kwargs):
    '''
    Extracts all values from given dict_object and listifies them.
    '''
    result = []
    fetch = dict_object.get
    if pop:
        fetch = dict_object.pop
    # If there's only one key, we don't return a list with one element
    if len(keys) == 1:
        return listify(fetch(keys[0], []), **kwargs)
    # Return a list of values corresponding to *keys
    for key in keys:
        result.append(listify(fetch(key, []), **kwargs))
    return result


def typeslistify(item, types):
    '''
    Ensure that type(@item) is one of @types or a
    list of items all of which are of type @types
    '''
    if isinstance(item, types):
        item = [item]
    if not isinstance(item, list):
        raise MesonException('Item must be a list or one of {!r}'.format(types))
    for i in item:
        if i is not None and not isinstance(i, types):
            raise MesonException('List item must be one of {!r}'.format(types))
    return item

def stringlistify(item):
    return typeslistify(item, str)

def expand_arguments(args):
    expended_args = []
    for arg in args:
        if not arg.startswith('@'):
            expended_args.append(arg)
            continue

        args_file = arg[1:]
        try:
            with open(args_file) as f:
                extended_args = f.read().split()
            expended_args += extended_args
        except Exception as e:
            print('Error expanding command line arguments, %s not found' % args_file)
            print(e)
            return None
    return expended_args

def Popen_safe(args, write=None, stderr=subprocess.PIPE, **kwargs):
    import locale
    encoding = locale.getpreferredencoding()
    if sys.version_info < (3, 6) or not sys.stdout.encoding or encoding.upper() != 'UTF-8':
        return Popen_safe_legacy(args, write=write, stderr=stderr, **kwargs)
    p = subprocess.Popen(args, universal_newlines=True,
                         close_fds=False,
                         stdout=subprocess.PIPE,
                         stderr=stderr, **kwargs)
    o, e = p.communicate(write)
    return p, o, e

def Popen_safe_legacy(args, write=None, stderr=subprocess.PIPE, **kwargs):
    p = subprocess.Popen(args, universal_newlines=False,
                         stdout=subprocess.PIPE,
                         stderr=stderr, **kwargs)
    if write is not None:
        write = write.encode('utf-8')
    o, e = p.communicate(write)
    if o is not None:
        if sys.stdout.encoding:
            o = o.decode(encoding=sys.stdout.encoding, errors='replace').replace('\r\n', '\n')
        else:
            o = o.decode(errors='replace').replace('\r\n', '\n')
    if e is not None:
        if sys.stderr.encoding:
            e = e.decode(encoding=sys.stderr.encoding, errors='replace').replace('\r\n', '\n')
        else:
            e = e.decode(errors='replace').replace('\r\n', '\n')
    return p, o, e

def iter_regexin_iter(regexiter, initer):
    '''
    Takes each regular expression in @regexiter and tries to search for it in
    every item in @initer. If there is a match, returns that match.
    Else returns False.
    '''
    for regex in regexiter:
        for ii in initer:
            if not isinstance(ii, str):
                continue
            match = re.search(regex, ii)
            if match:
                return match.group()
    return False

def _substitute_values_check_errors(command, values):
    # Error checking
    inregex = ('@INPUT([0-9]+)?@', '@PLAINNAME@', '@BASENAME@')
    outregex = ('@OUTPUT([0-9]+)?@', '@OUTDIR@')
    if '@INPUT@' not in values:
        # Error out if any input-derived templates are present in the command
        match = iter_regexin_iter(inregex, command)
        if match:
            m = 'Command cannot have {!r}, since no input files were specified'
            raise MesonException(m.format(match))
    else:
        if len(values['@INPUT@']) > 1:
            # Error out if @PLAINNAME@ or @BASENAME@ is present in the command
            match = iter_regexin_iter(inregex[1:], command)
            if match:
                raise MesonException('Command cannot have {!r} when there is '
                                     'more than one input file'.format(match))
        # Error out if an invalid @INPUTnn@ template was specified
        for each in command:
            if not isinstance(each, str):
                continue
            match = re.search(inregex[0], each)
            if match and match.group() not in values:
                m = 'Command cannot have {!r} since there are only {!r} inputs'
                raise MesonException(m.format(match.group(), len(values['@INPUT@'])))
    if '@OUTPUT@' not in values:
        # Error out if any output-derived templates are present in the command
        match = iter_regexin_iter(outregex, command)
        if match:
            m = 'Command cannot have {!r} since there are no outputs'
            raise MesonException(m.format(match))
    else:
        # Error out if an invalid @OUTPUTnn@ template was specified
        for each in command:
            if not isinstance(each, str):
                continue
            match = re.search(outregex[0], each)
            if match and match.group() not in values:
                m = 'Command cannot have {!r} since there are only {!r} outputs'
                raise MesonException(m.format(match.group(), len(values['@OUTPUT@'])))

def substitute_values(command, values):
    '''
    Substitute the template strings in the @values dict into the list of
    strings @command and return a new list. For a full list of the templates,
    see get_filenames_templates_dict()

    If multiple inputs/outputs are given in the @values dictionary, we
    substitute @INPUT@ and @OUTPUT@ only if they are the entire string, not
    just a part of it, and in that case we substitute *all* of them.
    '''
    # Error checking
    _substitute_values_check_errors(command, values)
    # Substitution
    outcmd = []
    rx_keys = [re.escape(key) for key in values if key not in ('@INPUT@', '@OUTPUT@')]
    value_rx = re.compile('|'.join(rx_keys)) if rx_keys else None
    for vv in command:
        if not isinstance(vv, str):
            outcmd.append(vv)
        elif '@INPUT@' in vv:
            inputs = values['@INPUT@']
            if vv == '@INPUT@':
                outcmd += inputs
            elif len(inputs) == 1:
                outcmd.append(vv.replace('@INPUT@', inputs[0]))
            else:
                raise MesonException("Command has '@INPUT@' as part of a "
                                     "string and more than one input file")
        elif '@OUTPUT@' in vv:
            outputs = values['@OUTPUT@']
            if vv == '@OUTPUT@':
                outcmd += outputs
            elif len(outputs) == 1:
                outcmd.append(vv.replace('@OUTPUT@', outputs[0]))
            else:
                raise MesonException("Command has '@OUTPUT@' as part of a "
                                     "string and more than one output file")
        # Append values that are exactly a template string.
        # This is faster than a string replace.
        elif vv in values:
            outcmd.append(values[vv])
        # Substitute everything else with replacement
        elif value_rx:
            outcmd.append(value_rx.sub(lambda m: values[m.group(0)], vv))
        else:
            outcmd.append(vv)
    return outcmd

def get_filenames_templates_dict(inputs, outputs):
    '''
    Create a dictionary with template strings as keys and values as values for
    the following templates:

    @INPUT@  - the full path to one or more input files, from @inputs
    @OUTPUT@ - the full path to one or more output files, from @outputs
    @OUTDIR@ - the full path to the directory containing the output files

    If there is only one input file, the following keys are also created:

    @PLAINNAME@ - the filename of the input file
    @BASENAME@ - the filename of the input file with the extension removed

    If there is more than one input file, the following keys are also created:

    @INPUT0@, @INPUT1@, ... one for each input file

    If there is more than one output file, the following keys are also created:

    @OUTPUT0@, @OUTPUT1@, ... one for each output file
    '''
    values = {}
    # Gather values derived from the input
    if inputs:
        # We want to substitute all the inputs.
        values['@INPUT@'] = inputs
        for (ii, vv) in enumerate(inputs):
            # Write out @INPUT0@, @INPUT1@, ...
            values['@INPUT{}@'.format(ii)] = vv
        if len(inputs) == 1:
            # Just one value, substitute @PLAINNAME@ and @BASENAME@
            values['@PLAINNAME@'] = plain = os.path.basename(inputs[0])
            values['@BASENAME@'] = os.path.splitext(plain)[0]
    if outputs:
        # Gather values derived from the outputs, similar to above.
        values['@OUTPUT@'] = outputs
        for (ii, vv) in enumerate(outputs):
            values['@OUTPUT{}@'.format(ii)] = vv
        # Outdir should be the same for all outputs
        values['@OUTDIR@'] = os.path.dirname(outputs[0])
        # Many external programs fail on empty arguments.
        if values['@OUTDIR@'] == '':
            values['@OUTDIR@'] = '.'
    return values


def windows_proof_rmtree(f):
    # On Windows if anyone is holding a file open you can't
    # delete it. As an example an anti virus scanner might
    # be scanning files you are trying to delete. The only
    # way to fix this is to try again and again.
    delays = [0.1, 0.1, 0.2, 0.2, 0.2, 0.5, 0.5, 1, 1, 1, 1, 2]
    for d in delays:
        try:
            shutil.rmtree(f)
            return
        except FileNotFoundError:
            return
        except (OSError, PermissionError):
            time.sleep(d)
    # Try one last time and throw if it fails.
    shutil.rmtree(f)


def detect_subprojects(spdir_name, current_dir='', result=None):
    if result is None:
        result = {}
    spdir = os.path.join(current_dir, spdir_name)
    if not os.path.exists(spdir):
        return result
    for trial in glob(os.path.join(spdir, '*')):
        basename = os.path.basename(trial)
        if trial == 'packagecache':
            continue
        append_this = True
        if os.path.isdir(trial):
            detect_subprojects(spdir_name, trial, result)
        elif trial.endswith('.wrap') and os.path.isfile(trial):
            basename = os.path.splitext(basename)[0]
        else:
            append_this = False
        if append_this:
            if basename in result:
                result[basename].append(trial)
            else:
                result[basename] = [trial]
    return result

class OrderedSet(collections.MutableSet):
    """A set that preserves the order in which items are added, by first
    insertion.
    """
    def __init__(self, iterable=None):
        self.__container = collections.OrderedDict()
        if iterable:
            self.update(iterable)

    def __contains__(self, value):
        return value in self.__container

    def __iter__(self):
        return iter(self.__container.keys())

    def __len__(self):
        return len(self.__container)

    def __repr__(self):
        # Don't print 'OrderedSet("")' for an empty set.
        if self.__container:
            return 'OrderedSet("{}")'.format(
                '", "'.join(repr(e) for e in self.__container.keys()))
        return 'OrderedSet()'

    def add(self, value):
        self.__container[value] = None

    def discard(self, value):
        if value in self.__container:
            del self.__container[value]

    def update(self, iterable):
        for item in iterable:
            self.__container[item] = None

    def difference(self, set_):
        return type(self)(e for e in self if e not in set_)

class BuildDirLock:

    def __init__(self, builddir):
        self.lockfilename = os.path.join(builddir, 'meson-private/meson.lock')

    def __enter__(self):
        self.lockfile = open(self.lockfilename, 'w')
        try:
            if have_fcntl:
                fcntl.flock(self.lockfile, fcntl.LOCK_EX | fcntl.LOCK_NB)
            elif have_msvcrt:
                msvcrt.locking(self.lockfile.fileno(), msvcrt.LK_NBLCK, 1)
        except (BlockingIOError, PermissionError):
            self.lockfile.close()
            raise MesonException('Some other Meson process is already using this build directory. Exiting.')

    def __exit__(self, *args):
        if have_fcntl:
            fcntl.flock(self.lockfile, fcntl.LOCK_UN)
        elif have_msvcrt:
            msvcrt.locking(self.lockfile.fileno(), msvcrt.LK_UNLCK, 1)
        self.lockfile.close()