| # SPDX-License-Identifier: Apache-2.0 |
| # Copyright 2013-2021 The Meson development team |
| |
| from __future__ import annotations |
| |
| from pathlib import Path |
| |
| from .base import ExternalDependency, DependencyException, sort_libpaths, DependencyTypeName |
| from ..mesonlib import EnvironmentVariables, OptionKey, OrderedSet, PerMachine, Popen_safe, Popen_safe_logged, MachineChoice, join_args |
| from ..programs import find_external_program, ExternalProgram |
| from .. import mlog |
| from pathlib import PurePath |
| from functools import lru_cache |
| import re |
| import os |
| import shlex |
| import typing as T |
| |
| if T.TYPE_CHECKING: |
| from typing_extensions import Literal |
| from .._typing import ImmutableListProtocol |
| |
| from ..environment import Environment |
| from ..utils.core import EnvironOrDict |
| from ..interpreter.type_checking import PkgConfigDefineType |
| |
| class PkgConfigInterface: |
| '''Base class wrapping a pkg-config implementation''' |
| |
| class_impl: PerMachine[T.Union[Literal[False], T.Optional[PkgConfigInterface]]] = PerMachine(False, False) |
| class_cli_impl: PerMachine[T.Union[Literal[False], T.Optional[PkgConfigCLI]]] = PerMachine(False, False) |
| |
| @staticmethod |
| def instance(env: Environment, for_machine: MachineChoice, silent: bool) -> T.Optional[PkgConfigInterface]: |
| '''Return a pkg-config implementation singleton''' |
| for_machine = for_machine if env.is_cross_build() else MachineChoice.HOST |
| impl = PkgConfigInterface.class_impl[for_machine] |
| if impl is False: |
| impl = PkgConfigCLI(env, for_machine, silent) |
| if not impl.found(): |
| impl = None |
| if not impl and not silent: |
| mlog.log('Found pkg-config:', mlog.red('NO')) |
| PkgConfigInterface.class_impl[for_machine] = impl |
| return impl |
| |
| @staticmethod |
| def _cli(env: Environment, for_machine: MachineChoice, silent: bool = False) -> T.Optional[PkgConfigCLI]: |
| '''Return the CLI pkg-config implementation singleton |
| Even when we use another implementation internally, external tools might |
| still need the CLI implementation. |
| ''' |
| for_machine = for_machine if env.is_cross_build() else MachineChoice.HOST |
| impl: T.Union[Literal[False], T.Optional[PkgConfigInterface]] # Help confused mypy |
| impl = PkgConfigInterface.instance(env, for_machine, silent) |
| if impl and not isinstance(impl, PkgConfigCLI): |
| impl = PkgConfigInterface.class_cli_impl[for_machine] |
| if impl is False: |
| impl = PkgConfigCLI(env, for_machine, silent) |
| if not impl.found(): |
| impl = None |
| PkgConfigInterface.class_cli_impl[for_machine] = impl |
| return T.cast('T.Optional[PkgConfigCLI]', impl) # Trust me, mypy |
| |
| @staticmethod |
| def get_env(env: Environment, for_machine: MachineChoice, uninstalled: bool = False) -> EnvironmentVariables: |
| cli = PkgConfigInterface._cli(env, for_machine) |
| return cli._get_env(uninstalled) if cli else EnvironmentVariables() |
| |
| @staticmethod |
| def setup_env(environ: EnvironOrDict, env: Environment, for_machine: MachineChoice, |
| uninstalled: bool = False) -> EnvironOrDict: |
| cli = PkgConfigInterface._cli(env, for_machine) |
| return cli._setup_env(environ, uninstalled) if cli else environ |
| |
| def __init__(self, env: Environment, for_machine: MachineChoice) -> None: |
| self.env = env |
| self.for_machine = for_machine |
| |
| def found(self) -> bool: |
| '''Return whether pkg-config is supported''' |
| raise NotImplementedError |
| |
| def version(self, name: str) -> T.Optional[str]: |
| '''Return module version or None if not found''' |
| raise NotImplementedError |
| |
| def cflags(self, name: str, allow_system: bool = False, |
| define_variable: PkgConfigDefineType = None) -> ImmutableListProtocol[str]: |
| '''Return module cflags |
| @allow_system: If False, remove default system include paths |
| ''' |
| raise NotImplementedError |
| |
| def libs(self, name: str, static: bool = False, allow_system: bool = False, |
| define_variable: PkgConfigDefineType = None) -> ImmutableListProtocol[str]: |
| '''Return module libs |
| @static: If True, also include private libraries |
| @allow_system: If False, remove default system libraries search paths |
| ''' |
| raise NotImplementedError |
| |
| def variable(self, name: str, variable_name: str, |
| define_variable: PkgConfigDefineType) -> T.Optional[str]: |
| '''Return module variable or None if variable is not defined''' |
| raise NotImplementedError |
| |
| def list_all(self) -> ImmutableListProtocol[str]: |
| '''Return all available pkg-config modules''' |
| raise NotImplementedError |
| |
| class PkgConfigCLI(PkgConfigInterface): |
| '''pkg-config CLI implementation''' |
| |
| def __init__(self, env: Environment, for_machine: MachineChoice, silent: bool) -> None: |
| super().__init__(env, for_machine) |
| self._detect_pkgbin() |
| if self.pkgbin and not silent: |
| mlog.log('Found pkg-config:', mlog.green('YES'), mlog.bold(f'({self.pkgbin.get_path()})'), mlog.blue(self.pkgbin_version)) |
| |
| def found(self) -> bool: |
| return bool(self.pkgbin) |
| |
| @lru_cache(maxsize=None) |
| def version(self, name: str) -> T.Optional[str]: |
| mlog.debug(f'Determining dependency {name!r} with pkg-config executable {self.pkgbin.get_path()!r}') |
| ret, version, _ = self._call_pkgbin(['--modversion', name]) |
| return version if ret == 0 else None |
| |
| @staticmethod |
| def _define_variable_args(define_variable: PkgConfigDefineType) -> T.List[str]: |
| ret = [] |
| if define_variable: |
| for pair in define_variable: |
| ret.append('--define-variable=' + '='.join(pair)) |
| return ret |
| |
| @lru_cache(maxsize=None) |
| def cflags(self, name: str, allow_system: bool = False, |
| define_variable: PkgConfigDefineType = None) -> ImmutableListProtocol[str]: |
| env = None |
| if allow_system: |
| env = os.environ.copy() |
| env['PKG_CONFIG_ALLOW_SYSTEM_CFLAGS'] = '1' |
| args: T.List[str] = [] |
| args += self._define_variable_args(define_variable) |
| args += ['--cflags', name] |
| ret, out, err = self._call_pkgbin(args, env=env) |
| if ret != 0: |
| raise DependencyException(f'Could not generate cflags for {name}:\n{err}\n') |
| return self._split_args(out) |
| |
| @lru_cache(maxsize=None) |
| def libs(self, name: str, static: bool = False, allow_system: bool = False, |
| define_variable: PkgConfigDefineType = None) -> ImmutableListProtocol[str]: |
| env = None |
| if allow_system: |
| env = os.environ.copy() |
| env['PKG_CONFIG_ALLOW_SYSTEM_LIBS'] = '1' |
| args: T.List[str] = [] |
| args += self._define_variable_args(define_variable) |
| if static: |
| args.append('--static') |
| args += ['--libs', name] |
| ret, out, err = self._call_pkgbin(args, env=env) |
| if ret != 0: |
| raise DependencyException(f'Could not generate libs for {name}:\n{err}\n') |
| return self._split_args(out) |
| |
| @lru_cache(maxsize=None) |
| def variable(self, name: str, variable_name: str, |
| define_variable: PkgConfigDefineType) -> T.Optional[str]: |
| args: T.List[str] = [] |
| args += self._define_variable_args(define_variable) |
| args += ['--variable=' + variable_name, name] |
| ret, out, err = self._call_pkgbin(args) |
| if ret != 0: |
| raise DependencyException(f'Could not get variable for {name}:\n{err}\n') |
| variable = out.strip() |
| # pkg-config doesn't distinguish between empty and nonexistent variables |
| # use the variable list to check for variable existence |
| if not variable: |
| ret, out, _ = self._call_pkgbin(['--print-variables', name]) |
| if not re.search(rf'^{variable_name}$', out, re.MULTILINE): |
| return None |
| mlog.debug(f'Got pkg-config variable {variable_name} : {variable}') |
| return variable |
| |
| @lru_cache(maxsize=None) |
| def list_all(self) -> ImmutableListProtocol[str]: |
| ret, out, err = self._call_pkgbin(['--list-all']) |
| if ret != 0: |
| raise DependencyException(f'could not list modules:\n{err}\n') |
| return [i.split(' ', 1)[0] for i in out.splitlines()] |
| |
| @staticmethod |
| def _split_args(cmd: str) -> T.List[str]: |
| # pkg-config paths follow Unix conventions, even on Windows; split the |
| # output using shlex.split rather than mesonlib.split_args |
| return shlex.split(cmd) |
| |
| def _detect_pkgbin(self) -> None: |
| for potential_pkgbin in find_external_program( |
| self.env, self.for_machine, 'pkg-config', 'Pkg-config', |
| self.env.default_pkgconfig, allow_default_for_cross=False): |
| version_if_ok = self._check_pkgconfig(potential_pkgbin) |
| if version_if_ok: |
| self.pkgbin = potential_pkgbin |
| self.pkgbin_version = version_if_ok |
| return |
| self.pkgbin = None |
| |
| def _check_pkgconfig(self, pkgbin: ExternalProgram) -> T.Optional[str]: |
| if not pkgbin.found(): |
| mlog.log(f'Did not find pkg-config by name {pkgbin.name!r}') |
| return None |
| command_as_string = ' '.join(pkgbin.get_command()) |
| try: |
| helptext = Popen_safe(pkgbin.get_command() + ['--help'])[1] |
| if 'Pure-Perl' in helptext: |
| mlog.log(f'Found pkg-config {command_as_string!r} but it is Strawberry Perl and thus broken. Ignoring...') |
| return None |
| p, out = Popen_safe(pkgbin.get_command() + ['--version'])[0:2] |
| if p.returncode != 0: |
| mlog.warning(f'Found pkg-config {command_as_string!r} but it failed when ran') |
| return None |
| except FileNotFoundError: |
| mlog.warning(f'We thought we found pkg-config {command_as_string!r} but now it\'s not there. How odd!') |
| return None |
| except PermissionError: |
| msg = f'Found pkg-config {command_as_string!r} but didn\'t have permissions to run it.' |
| if not self.env.machines.build.is_windows(): |
| msg += '\n\nOn Unix-like systems this is often caused by scripts that are not executable.' |
| mlog.warning(msg) |
| return None |
| return out.strip() |
| |
| def _get_env(self, uninstalled: bool = False) -> EnvironmentVariables: |
| env = EnvironmentVariables() |
| key = OptionKey('pkg_config_path', machine=self.for_machine) |
| extra_paths: T.List[str] = self.env.coredata.options[key].value[:] |
| if uninstalled: |
| uninstalled_path = Path(self.env.get_build_dir(), 'meson-uninstalled').as_posix() |
| if uninstalled_path not in extra_paths: |
| extra_paths.append(uninstalled_path) |
| env.set('PKG_CONFIG_PATH', extra_paths) |
| sysroot = self.env.properties[self.for_machine].get_sys_root() |
| if sysroot: |
| env.set('PKG_CONFIG_SYSROOT_DIR', [sysroot]) |
| pkg_config_libdir_prop = self.env.properties[self.for_machine].get_pkg_config_libdir() |
| if pkg_config_libdir_prop: |
| env.set('PKG_CONFIG_LIBDIR', pkg_config_libdir_prop) |
| env.set('PKG_CONFIG', [join_args(self.pkgbin.get_command())]) |
| return env |
| |
| def _setup_env(self, env: EnvironOrDict, uninstalled: bool = False) -> T.Dict[str, str]: |
| envvars = self._get_env(uninstalled) |
| env = envvars.get_env(env) |
| # Dump all PKG_CONFIG environment variables |
| for key, value in env.items(): |
| if key.startswith('PKG_'): |
| mlog.debug(f'env[{key}]: {value}') |
| return env |
| |
| def _call_pkgbin(self, args: T.List[str], env: T.Optional[EnvironOrDict] = None) -> T.Tuple[int, str, str]: |
| assert isinstance(self.pkgbin, ExternalProgram) |
| env = env or os.environ |
| env = self._setup_env(env) |
| cmd = self.pkgbin.get_command() + args |
| p, out, err = Popen_safe_logged(cmd, env=env) |
| return p.returncode, out.strip(), err.strip() |
| |
| |
| class PkgConfigDependency(ExternalDependency): |
| |
| def __init__(self, name: str, environment: Environment, kwargs: T.Dict[str, T.Any], language: T.Optional[str] = None) -> None: |
| super().__init__(DependencyTypeName('pkgconfig'), environment, kwargs, language=language) |
| self.name = name |
| self.is_libtool = False |
| pkgconfig = PkgConfigInterface.instance(self.env, self.for_machine, self.silent) |
| if not pkgconfig: |
| msg = f'Pkg-config for machine {self.for_machine} not found. Giving up.' |
| if self.required: |
| raise DependencyException(msg) |
| mlog.debug(msg) |
| return |
| self.pkgconfig = pkgconfig |
| |
| version = self.pkgconfig.version(name) |
| if version is None: |
| return |
| |
| self.version = version |
| self.is_found = True |
| |
| try: |
| # Fetch cargs to be used while using this dependency |
| self._set_cargs() |
| # Fetch the libraries and library paths needed for using this |
| self._set_libs() |
| except DependencyException as e: |
| mlog.debug(f"Pkg-config error with '{name}': {e}") |
| if self.required: |
| raise |
| else: |
| self.compile_args = [] |
| self.link_args = [] |
| self.is_found = False |
| self.reason = e |
| |
| def __repr__(self) -> str: |
| s = '<{0} {1}: {2} {3}>' |
| return s.format(self.__class__.__name__, self.name, self.is_found, |
| self.version_reqs) |
| |
| def _convert_mingw_paths(self, args: ImmutableListProtocol[str]) -> T.List[str]: |
| ''' |
| Both MSVC and native Python on Windows cannot handle MinGW-esque /c/foo |
| paths so convert them to C:/foo. We cannot resolve other paths starting |
| with / like /home/foo so leave them as-is so that the user gets an |
| error/warning from the compiler/linker. |
| ''' |
| if not self.env.machines.build.is_windows(): |
| return args.copy() |
| converted = [] |
| for arg in args: |
| pargs: T.Tuple[str, ...] = tuple() |
| # Library search path |
| if arg.startswith('-L/'): |
| pargs = PurePath(arg[2:]).parts |
| tmpl = '-L{}:/{}' |
| elif arg.startswith('-I/'): |
| pargs = PurePath(arg[2:]).parts |
| tmpl = '-I{}:/{}' |
| # Full path to library or .la file |
| elif arg.startswith('/'): |
| pargs = PurePath(arg).parts |
| tmpl = '{}:/{}' |
| elif arg.startswith(('-L', '-I')) or (len(arg) > 2 and arg[1] == ':'): |
| # clean out improper '\\ ' as comes from some Windows pkg-config files |
| arg = arg.replace('\\ ', ' ') |
| if len(pargs) > 1 and len(pargs[1]) == 1: |
| arg = tmpl.format(pargs[1], '/'.join(pargs[2:])) |
| converted.append(arg) |
| return converted |
| |
| def _set_cargs(self) -> None: |
| allow_system = False |
| if self.language == 'fortran': |
| # gfortran doesn't appear to look in system paths for INCLUDE files, |
| # so don't allow pkg-config to suppress -I flags for system paths |
| allow_system = True |
| cflags = self.pkgconfig.cflags(self.name, allow_system) |
| self.compile_args = self._convert_mingw_paths(cflags) |
| |
| def _search_libs(self, libs_in: ImmutableListProtocol[str], raw_libs_in: ImmutableListProtocol[str]) -> T.Tuple[T.List[str], T.List[str]]: |
| ''' |
| @libs_in: PKG_CONFIG_ALLOW_SYSTEM_LIBS=1 pkg-config --libs |
| @raw_libs_in: pkg-config --libs |
| |
| We always look for the file ourselves instead of depending on the |
| compiler to find it with -lfoo or foo.lib (if possible) because: |
| 1. We want to be able to select static or shared |
| 2. We need the full path of the library to calculate RPATH values |
| 3. De-dup of libraries is easier when we have absolute paths |
| |
| Libraries that are provided by the toolchain or are not found by |
| find_library() will be added with -L -l pairs. |
| ''' |
| # Library paths should be safe to de-dup |
| # |
| # First, figure out what library paths to use. Originally, we were |
| # doing this as part of the loop, but due to differences in the order |
| # of -L values between pkg-config and pkgconf, we need to do that as |
| # a separate step. See: |
| # https://github.com/mesonbuild/meson/issues/3951 |
| # https://github.com/mesonbuild/meson/issues/4023 |
| # |
| # Separate system and prefix paths, and ensure that prefix paths are |
| # always searched first. |
| prefix_libpaths: OrderedSet[str] = OrderedSet() |
| # We also store this raw_link_args on the object later |
| raw_link_args = self._convert_mingw_paths(raw_libs_in) |
| for arg in raw_link_args: |
| if arg.startswith('-L') and not arg.startswith(('-L-l', '-L-L')): |
| path = arg[2:] |
| if not os.path.isabs(path): |
| # Resolve the path as a compiler in the build directory would |
| path = os.path.join(self.env.get_build_dir(), path) |
| prefix_libpaths.add(path) |
| # Library paths are not always ordered in a meaningful way |
| # |
| # Instead of relying on pkg-config or pkgconf to provide -L flags in a |
| # specific order, we reorder library paths ourselves, according to th |
| # order specified in PKG_CONFIG_PATH. See: |
| # https://github.com/mesonbuild/meson/issues/4271 |
| # |
| # Only prefix_libpaths are reordered here because there should not be |
| # too many system_libpaths to cause library version issues. |
| pkg_config_path: T.List[str] = self.env.coredata.options[OptionKey('pkg_config_path', machine=self.for_machine)].value |
| pkg_config_path = self._convert_mingw_paths(pkg_config_path) |
| prefix_libpaths = OrderedSet(sort_libpaths(list(prefix_libpaths), pkg_config_path)) |
| system_libpaths: OrderedSet[str] = OrderedSet() |
| full_args = self._convert_mingw_paths(libs_in) |
| for arg in full_args: |
| if arg.startswith(('-L-l', '-L-L')): |
| # These are D language arguments, not library paths |
| continue |
| if arg.startswith('-L') and arg[2:] not in prefix_libpaths: |
| system_libpaths.add(arg[2:]) |
| # Use this re-ordered path list for library resolution |
| libpaths = list(prefix_libpaths) + list(system_libpaths) |
| # Track -lfoo libraries to avoid duplicate work |
| libs_found: OrderedSet[str] = OrderedSet() |
| # Track not-found libraries to know whether to add library paths |
| libs_notfound = [] |
| # Generate link arguments for this library |
| link_args = [] |
| for lib in full_args: |
| if lib.startswith(('-L-l', '-L-L')): |
| # These are D language arguments, add them as-is |
| pass |
| elif lib.startswith('-L'): |
| # We already handled library paths above |
| continue |
| elif lib.startswith('-l:'): |
| # see: https://stackoverflow.com/questions/48532868/gcc-library-option-with-a-colon-llibevent-a |
| # also : See the documentation of -lnamespec | --library=namespec in the linker manual |
| # https://sourceware.org/binutils/docs-2.18/ld/Options.html |
| |
| # Don't resolve the same -l:libfoo.a argument again |
| if lib in libs_found: |
| continue |
| libfilename = lib[3:] |
| foundname = None |
| for libdir in libpaths: |
| target = os.path.join(libdir, libfilename) |
| if os.path.exists(target): |
| foundname = target |
| break |
| if foundname is None: |
| if lib in libs_notfound: |
| continue |
| else: |
| mlog.warning('Library {!r} not found for dependency {!r}, may ' |
| 'not be successfully linked'.format(libfilename, self.name)) |
| libs_notfound.append(lib) |
| else: |
| lib = foundname |
| elif lib.startswith('-l'): |
| # Don't resolve the same -lfoo argument again |
| if lib in libs_found: |
| continue |
| if self.clib_compiler: |
| args = self.clib_compiler.find_library(lib[2:], self.env, |
| libpaths, self.libtype, |
| lib_prefix_warning=False) |
| # If the project only uses a non-clib language such as D, Rust, |
| # C#, Python, etc, all we can do is limp along by adding the |
| # arguments as-is and then adding the libpaths at the end. |
| else: |
| args = None |
| if args is not None: |
| libs_found.add(lib) |
| # Replace -l arg with full path to library if available |
| # else, library is either to be ignored, or is provided by |
| # the compiler, can't be resolved, and should be used as-is |
| if args: |
| if not args[0].startswith('-l'): |
| lib = args[0] |
| else: |
| continue |
| else: |
| # Library wasn't found, maybe we're looking in the wrong |
| # places or the library will be provided with LDFLAGS or |
| # LIBRARY_PATH from the environment (on macOS), and many |
| # other edge cases that we can't account for. |
| # |
| # Add all -L paths and use it as -lfoo |
| if lib in libs_notfound: |
| continue |
| if self.static: |
| mlog.warning('Static library {!r} not found for dependency {!r}, may ' |
| 'not be statically linked'.format(lib[2:], self.name)) |
| libs_notfound.append(lib) |
| elif lib.endswith(".la"): |
| shared_libname = self.extract_libtool_shlib(lib) |
| shared_lib = os.path.join(os.path.dirname(lib), shared_libname) |
| if not os.path.exists(shared_lib): |
| shared_lib = os.path.join(os.path.dirname(lib), ".libs", shared_libname) |
| |
| if not os.path.exists(shared_lib): |
| raise DependencyException(f'Got a libtools specific "{lib}" dependencies' |
| 'but we could not compute the actual shared' |
| 'library path') |
| self.is_libtool = True |
| lib = shared_lib |
| if lib in link_args: |
| continue |
| link_args.append(lib) |
| # Add all -Lbar args if we have -lfoo args in link_args |
| if libs_notfound: |
| # Order of -L flags doesn't matter with ld, but it might with other |
| # linkers such as MSVC, so prepend them. |
| link_args = ['-L' + lp for lp in prefix_libpaths] + link_args |
| return link_args, raw_link_args |
| |
| def _set_libs(self) -> None: |
| # Force pkg-config to output -L fields even if they are system |
| # paths so we can do manual searching with cc.find_library() later. |
| libs = self.pkgconfig.libs(self.name, self.static, allow_system=True) |
| # Also get the 'raw' output without -Lfoo system paths for adding -L |
| # args with -lfoo when a library can't be found, and also in |
| # gnome.generate_gir + gnome.gtkdoc which need -L -l arguments. |
| raw_libs = self.pkgconfig.libs(self.name, self.static, allow_system=False) |
| self.link_args, self.raw_link_args = self._search_libs(libs, raw_libs) |
| |
| def extract_field(self, la_file: str, fieldname: str) -> T.Optional[str]: |
| with open(la_file, encoding='utf-8') as f: |
| for line in f: |
| arr = line.strip().split('=') |
| if arr[0] == fieldname: |
| return arr[1][1:-1] |
| return None |
| |
| def extract_dlname_field(self, la_file: str) -> T.Optional[str]: |
| return self.extract_field(la_file, 'dlname') |
| |
| def extract_libdir_field(self, la_file: str) -> T.Optional[str]: |
| return self.extract_field(la_file, 'libdir') |
| |
| def extract_libtool_shlib(self, la_file: str) -> T.Optional[str]: |
| ''' |
| Returns the path to the shared library |
| corresponding to this .la file |
| ''' |
| dlname = self.extract_dlname_field(la_file) |
| if dlname is None: |
| return None |
| |
| # Darwin uses absolute paths where possible; since the libtool files never |
| # contain absolute paths, use the libdir field |
| if self.env.machines[self.for_machine].is_darwin(): |
| dlbasename = os.path.basename(dlname) |
| libdir = self.extract_libdir_field(la_file) |
| if libdir is None: |
| return dlbasename |
| return os.path.join(libdir, dlbasename) |
| # From the comments in extract_libtool(), older libtools had |
| # a path rather than the raw dlname |
| return os.path.basename(dlname) |
| |
| @staticmethod |
| def log_tried() -> str: |
| return 'pkgconfig' |
| |
| def get_variable(self, *, cmake: T.Optional[str] = None, pkgconfig: T.Optional[str] = None, |
| configtool: T.Optional[str] = None, internal: T.Optional[str] = None, |
| default_value: T.Optional[str] = None, |
| pkgconfig_define: PkgConfigDefineType = None) -> str: |
| if pkgconfig: |
| try: |
| variable = self.pkgconfig.variable(self.name, pkgconfig, pkgconfig_define) |
| if variable is not None: |
| return variable |
| except DependencyException: |
| pass |
| if default_value is not None: |
| return default_value |
| raise DependencyException(f'Could not get pkg-config variable and no default provided for {self!r}') |
