Split UI-related into a separate file.

Some of these are a bit bigger than just UI libraries, but this division
seems close enough.

3 files changed, 575 insertions, 530 deletions

diff --git a/mesonbuild/dependencies/__init__.py b/mesonbuild/dependencies/__init__.py
index 9281798..fb2bee0 100644
--- a/mesonbuild/dependencies/__init__.py
+++ b/mesonbuild/dependencies/__init__.py
@@ -13,3 +13,15 @@
 # limitations under the License.
 
 from .base import *
+from .ui import GLDependency, GnuStepDependency, Qt4Dependency, Qt5Dependency, SDL2Dependency, WxDependency
+
+
+# From _ui:
+packages.update({
+    'gl': GLDependency,
+    'gnustep': GnuStepDependency,
+    'qt4': Qt4Dependency,
+    'qt5': Qt5Dependency,
+    'sdl2': SDL2Dependency,
+    'wxwidgets': WxDependency,
+})
diff --git a/mesonbuild/dependencies/base.py b/mesonbuild/dependencies/base.py
index 3c9876c..c8b8735 100644
--- a/mesonbuild/dependencies/base.py
+++ b/mesonbuild/dependencies/base.py
@@ -19,19 +19,17 @@
 # Currently one file, should probably be split into a
 # package before this gets too big.
 
-import re
 import sys
 import os, stat, glob, shutil
 import shlex
-import subprocess
 import sysconfig
 from enum import Enum
-from collections import OrderedDict
 from .. import mlog
 from .. import mesonlib
 from ..mesonlib import Popen_safe, flatten
 from ..mesonlib import MesonException, version_compare, version_compare_many
-from ..environment import detect_cpu_family, for_windows
+from ..environment import detect_cpu_family
+
 
 class DependencyException(MesonException):
     '''Exceptions raised while trying to find dependencies'''
@@ -353,93 +351,6 @@ class PkgConfigDependency(Dependency):
         # a path rather than the raw dlname
         return os.path.basename(dlname)
 
-class WxDependency(Dependency):
-    wx_found = None
-
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'wx', kwargs)
-        self.is_found = False
-        # FIXME: use version instead of modversion
-        self.modversion = 'none'
-        if WxDependency.wx_found is None:
-            self.check_wxconfig()
-        if not WxDependency.wx_found:
-            # FIXME: this message could be printed after Dependncy found
-            mlog.log("Neither wx-config-3.0 nor wx-config found; can't detect dependency")
-            return
-
-        # FIXME: This should print stdout and stderr using mlog.debug
-        p, out = Popen_safe([self.wxc, '--version'])[0:2]
-        if p.returncode != 0:
-            mlog.log('Dependency wxwidgets found:', mlog.red('NO'))
-            self.cargs = []
-            self.libs = []
-        else:
-            self.modversion = out.strip()
-            version_req = kwargs.get('version', None)
-            if version_req is not None:
-                if not version_compare(self.modversion, version_req, strict=True):
-                    mlog.log('Wxwidgets version %s does not fullfill requirement %s' %
-                             (self.modversion, version_req))
-                    return
-            mlog.log('Dependency wxwidgets found:', mlog.green('YES'))
-            self.is_found = True
-            self.requested_modules = self.get_requested(kwargs)
-            # wx-config seems to have a cflags as well but since it requires C++,
-            # this should be good, at least for now.
-            p, out = Popen_safe([self.wxc, '--cxxflags'])[0:2]
-            # FIXME: this error should only be raised if required is true
-            if p.returncode != 0:
-                raise DependencyException('Could not generate cargs for wxwidgets.')
-            self.cargs = out.split()
-
-            # FIXME: this error should only be raised if required is true
-            p, out = Popen_safe([self.wxc, '--libs'] + self.requested_modules)[0:2]
-            if p.returncode != 0:
-                raise DependencyException('Could not generate libs for wxwidgets.')
-            self.libs = out.split()
-
-    def get_requested(self, kwargs):
-        modules = 'modules'
-        if modules not in kwargs:
-            return []
-        candidates = kwargs[modules]
-        if isinstance(candidates, str):
-            return [candidates]
-        for c in candidates:
-            if not isinstance(c, str):
-                raise DependencyException('wxwidgets module argument is not a string.')
-        return candidates
-
-    def get_modversion(self):
-        return self.modversion
-
-    def get_version(self):
-        return self.modversion
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.libs
-
-    def check_wxconfig(self):
-        for wxc in ['wx-config-3.0', 'wx-config']:
-            try:
-                p, out = Popen_safe([wxc, '--version'])[0:2]
-                if p.returncode == 0:
-                    mlog.log('Found wx-config:', mlog.bold(shutil.which(wxc)),
-                             '(%s)' % out.strip())
-                    self.wxc = wxc
-                    WxDependency.wx_found = True
-                    return
-            except (FileNotFoundError, PermissionError):
-                pass
-        WxDependency.wxconfig_found = False
-        mlog.log('Found wx-config:', mlog.red('NO'))
-
-    def found(self):
-        return self.is_found
 
 class ExternalProgram:
     windows_exts = ('exe', 'msc', 'com', 'bat')
@@ -1009,334 +920,6 @@ class GMockDependency(Dependency):
     def found(self):
         return self.is_found
 
-class QtBaseDependency(Dependency):
-    def __init__(self, name, env, kwargs):
-        Dependency.__init__(self, name, kwargs)
-        self.name = name
-        self.qtname = name.capitalize()
-        self.qtver = name[-1]
-        if self.qtver == "4":
-            self.qtpkgname = 'Qt'
-        else:
-            self.qtpkgname = self.qtname
-        self.root = '/usr'
-        self.bindir = None
-        self.silent = kwargs.get('silent', False)
-        # We store the value of required here instead of passing it on to
-        # PkgConfigDependency etc because we want to try the qmake-based
-        # fallback as well.
-        self.required = kwargs.pop('required', True)
-        kwargs['required'] = False
-        mods = kwargs.get('modules', [])
-        self.cargs = []
-        self.largs = []
-        self.is_found = False
-        if isinstance(mods, str):
-            mods = [mods]
-        if not mods:
-            raise DependencyException('No ' + self.qtname + '  modules specified.')
-        type_text = 'cross' if env.is_cross_build() else 'native'
-        found_msg = '{} {} {{}} dependency (modules: {}) found:' \
-                    ''.format(self.qtname, type_text, ', '.join(mods))
-        from_text = 'pkg-config'
-
-        # Keep track of the detection methods used, for logging purposes.
-        methods = []
-        # Prefer pkg-config, then fallback to `qmake -query`
-        if DependencyMethods.PKGCONFIG in self.methods:
-            self._pkgconfig_detect(mods, env, kwargs)
-            methods.append('pkgconfig')
-        if not self.is_found and DependencyMethods.QMAKE in self.methods:
-            from_text = self._qmake_detect(mods, env, kwargs)
-            methods.append('qmake-' + self.name)
-            methods.append('qmake')
-        if not self.is_found:
-            # Reset compile args and link args
-            self.cargs = []
-            self.largs = []
-            from_text = '(checked {})'.format(mlog.format_list(methods))
-            self.version = 'none'
-            if self.required:
-                err_msg = '{} {} dependency not found {}' \
-                          ''.format(self.qtname, type_text, from_text)
-                raise DependencyException(err_msg)
-            if not self.silent:
-                mlog.log(found_msg.format(from_text), mlog.red('NO'))
-            return
-        from_text = '`{}`'.format(from_text)
-        if not self.silent:
-            mlog.log(found_msg.format(from_text), mlog.green('YES'))
-
-    def compilers_detect(self):
-        "Detect Qt (4 or 5) moc, uic, rcc in the specified bindir or in PATH"
-        if self.bindir:
-            moc = ExternalProgram(os.path.join(self.bindir, 'moc'), silent=True)
-            uic = ExternalProgram(os.path.join(self.bindir, 'uic'), silent=True)
-            rcc = ExternalProgram(os.path.join(self.bindir, 'rcc'), silent=True)
-        else:
-            # We don't accept unsuffixed 'moc', 'uic', and 'rcc' because they
-            # are sometimes older, or newer versions.
-            moc = ExternalProgram('moc-' + self.name, silent=True)
-            uic = ExternalProgram('uic-' + self.name, silent=True)
-            rcc = ExternalProgram('rcc-' + self.name, silent=True)
-        return moc, uic, rcc
-
-    def _pkgconfig_detect(self, mods, env, kwargs):
-        modules = OrderedDict()
-        for module in mods:
-            modules[module] = PkgConfigDependency(self.qtpkgname + module, env, kwargs)
-        self.is_found = True
-        for m in modules.values():
-            if not m.found():
-                self.is_found = False
-                return
-            self.cargs += m.get_compile_args()
-            self.largs += m.get_link_args()
-        self.version = m.modversion
-        # Try to detect moc, uic, rcc
-        if 'Core' in modules:
-            core = modules['Core']
-        else:
-            corekwargs = {'required': 'false', 'silent': 'true'}
-            core = PkgConfigDependency(self.qtpkgname + 'Core', env, corekwargs)
-        # Used by self.compilers_detect()
-        self.bindir = self.get_pkgconfig_host_bins(core)
-        if not self.bindir:
-            # If exec_prefix is not defined, the pkg-config file is broken
-            prefix = core.get_pkgconfig_variable('exec_prefix')
-            if prefix:
-                self.bindir = os.path.join(prefix, 'bin')
-
-    def _find_qmake(self, qmake, env):
-        # Even when cross-compiling, if we don't get a cross-info qmake, we
-        # fallback to using the qmake in PATH because that's what we used to do
-        if env.is_cross_build():
-            qmake = env.cross_info.config['binaries'].get('qmake', qmake)
-        return ExternalProgram(qmake, silent=True)
-
-    def _qmake_detect(self, mods, env, kwargs):
-        for qmake in ('qmake-' + self.name, 'qmake'):
-            self.qmake = self._find_qmake(qmake, env)
-            if not self.qmake.found():
-                continue
-            # Check that the qmake is for qt5
-            pc, stdo = Popen_safe(self.qmake.get_command() + ['-v'])[0:2]
-            if pc.returncode != 0:
-                continue
-            if not 'Qt version ' + self.qtver in stdo:
-                mlog.log('QMake is not for ' + self.qtname)
-                continue
-            # Found qmake for Qt5!
-            break
-        else:
-            # Didn't find qmake :(
-            return
-        self.version = re.search(self.qtver + '(\.\d+)+', stdo).group(0)
-        # Query library path, header path, and binary path
-        mlog.log("Found qmake:", mlog.bold(self.qmake.get_name()), '(%s)' % self.version)
-        stdo = Popen_safe(self.qmake.get_command() + ['-query'])[1]
-        qvars = {}
-        for line in stdo.split('\n'):
-            line = line.strip()
-            if line == '':
-                continue
-            (k, v) = tuple(line.split(':', 1))
-            qvars[k] = v
-        if mesonlib.is_osx():
-            return self._framework_detect(qvars, mods, kwargs)
-        incdir = qvars['QT_INSTALL_HEADERS']
-        self.cargs.append('-I' + incdir)
-        libdir = qvars['QT_INSTALL_LIBS']
-        # Used by self.compilers_detect()
-        self.bindir = self.get_qmake_host_bins(qvars)
-        self.is_found = True
-        for module in mods:
-            mincdir = os.path.join(incdir, 'Qt' + module)
-            self.cargs.append('-I' + mincdir)
-            if for_windows(env.is_cross_build(), env):
-                libfile = os.path.join(libdir, self.qtpkgname + module + '.lib')
-                if not os.path.isfile(libfile):
-                    # MinGW can link directly to .dll
-                    libfile = os.path.join(self.bindir, self.qtpkgname + module + '.dll')
-                    if not os.path.isfile(libfile):
-                        self.is_found = False
-                        break
-            else:
-                libfile = os.path.join(libdir, 'lib{}{}.so'.format(self.qtpkgname, module))
-                if not os.path.isfile(libfile):
-                    self.is_found = False
-                    break
-            self.largs.append(libfile)
-        return qmake
-
-    def _framework_detect(self, qvars, modules, kwargs):
-        libdir = qvars['QT_INSTALL_LIBS']
-        for m in modules:
-            fname = 'Qt' + m
-            fwdep = ExtraFrameworkDependency(fname, kwargs.get('required', True), libdir, kwargs)
-            self.cargs.append('-F' + libdir)
-            if fwdep.found():
-                self.is_found = True
-                self.cargs += fwdep.get_compile_args()
-                self.largs += fwdep.get_link_args()
-        # Used by self.compilers_detect()
-        self.bindir = self.get_qmake_host_bins(qvars)
-
-    def get_qmake_host_bins(self, qvars):
-        # Prefer QT_HOST_BINS (qt5, correct for cross and native compiling)
-        # but fall back to QT_INSTALL_BINS (qt4)
-        if 'QT_HOST_BINS' in qvars:
-            return qvars['QT_HOST_BINS']
-        else:
-            return qvars['QT_INSTALL_BINS']
-
-    def get_version(self):
-        return self.version
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_sources(self):
-        return []
-
-    def get_link_args(self):
-        return self.largs
-
-    def get_methods(self):
-        return [DependencyMethods.PKGCONFIG, DependencyMethods.QMAKE]
-
-    def found(self):
-        return self.is_found
-
-    def get_exe_args(self, compiler):
-        # Originally this was -fPIE but nowadays the default
-        # for upstream and distros seems to be -reduce-relocations
-        # which requires -fPIC. This may cause a performance
-        # penalty when using self-built Qt or on platforms
-        # where -fPIC is not required. If this is an issue
-        # for you, patches are welcome.
-        return compiler.get_pic_args()
-
-class Qt5Dependency(QtBaseDependency):
-    def __init__(self, env, kwargs):
-        QtBaseDependency.__init__(self, 'qt5', env, kwargs)
-
-    def get_pkgconfig_host_bins(self, core):
-        return core.get_pkgconfig_variable('host_bins')
-
-class Qt4Dependency(QtBaseDependency):
-    def __init__(self, env, kwargs):
-        QtBaseDependency.__init__(self, 'qt4', env, kwargs)
-
-    def get_pkgconfig_host_bins(self, core):
-        # Only return one bins dir, because the tools are generally all in one
-        # directory for Qt4, in Qt5, they must all be in one directory. Return
-        # the first one found among the bin variables, in case one tool is not
-        # configured to be built.
-        applications = ['moc', 'uic', 'rcc', 'lupdate', 'lrelease']
-        for application in applications:
-            try:
-                return os.path.dirname(core.get_pkgconfig_variable('%s_location' % application))
-            except MesonException:
-                pass
-
-class GnuStepDependency(Dependency):
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'gnustep', kwargs)
-        self.required = kwargs.get('required', True)
-        self.modules = kwargs.get('modules', [])
-        self.detect()
-
-    def detect(self):
-        self.confprog = 'gnustep-config'
-        try:
-            gp = Popen_safe([self.confprog, '--help'])[0]
-        except (FileNotFoundError, PermissionError):
-            self.args = None
-            mlog.log('Dependency GnuStep found:', mlog.red('NO'), '(no gnustep-config)')
-            return
-        if gp.returncode != 0:
-            self.args = None
-            mlog.log('Dependency GnuStep found:', mlog.red('NO'))
-            return
-        if 'gui' in self.modules:
-            arg = '--gui-libs'
-        else:
-            arg = '--base-libs'
-        fp, flagtxt, flagerr = Popen_safe([self.confprog, '--objc-flags'])
-        if fp.returncode != 0:
-            raise DependencyException('Error getting objc-args: %s %s' % (flagtxt, flagerr))
-        args = flagtxt.split()
-        self.args = self.filter_arsg(args)
-        fp, libtxt, liberr = Popen_safe([self.confprog, arg])
-        if fp.returncode != 0:
-            raise DependencyException('Error getting objc-lib args: %s %s' % (libtxt, liberr))
-        self.libs = self.weird_filter(libtxt.split())
-        self.version = self.detect_version()
-        mlog.log('Dependency', mlog.bold('GnuStep'), 'found:',
-                 mlog.green('YES'), self.version)
-
-    def weird_filter(self, elems):
-        """When building packages, the output of the enclosing Make
-is sometimes mixed among the subprocess output. I have no idea
-why. As a hack filter out everything that is not a flag."""
-        return [e for e in elems if e.startswith('-')]
-
-    def filter_arsg(self, args):
-        """gnustep-config returns a bunch of garbage args such
-        as -O2 and so on. Drop everything that is not needed."""
-        result = []
-        for f in args:
-            if f.startswith('-D') \
-                    or f.startswith('-f') \
-                    or f.startswith('-I') \
-                    or f == '-pthread' \
-                    or (f.startswith('-W') and not f == '-Wall'):
-                result.append(f)
-        return result
-
-    def detect_version(self):
-        gmake = self.get_variable('GNUMAKE')
-        makefile_dir = self.get_variable('GNUSTEP_MAKEFILES')
-        # This Makefile has the GNUStep version set
-        base_make = os.path.join(makefile_dir, 'Additional', 'base.make')
-        # Print the Makefile variable passed as the argument. For instance, if
-        # you run the make target `print-SOME_VARIABLE`, this will print the
-        # value of the variable `SOME_VARIABLE`.
-        printver = "print-%:\n\t@echo '$($*)'"
-        env = os.environ.copy()
-        # See base.make to understand why this is set
-        env['FOUNDATION_LIB'] = 'gnu'
-        p, o, e = Popen_safe([gmake, '-f', '-', '-f', base_make,
-                              'print-GNUSTEP_BASE_VERSION'],
-                             env=env, write=printver, stdin=subprocess.PIPE)
-        version = o.strip()
-        if not version:
-            mlog.debug("Couldn't detect GNUStep version, falling back to '1'")
-            # Fallback to setting some 1.x version
-            version = '1'
-        return version
-
-    def get_variable(self, var):
-        p, o, e = Popen_safe([self.confprog, '--variable=' + var])
-        if p.returncode != 0 and self.required:
-            raise DependencyException('{!r} for variable {!r} failed to run'
-                                      ''.format(self.confprog, var))
-        return o.strip()
-
-    def found(self):
-        return self.args is not None
-
-    def get_version(self):
-        return self.version
-
-    def get_compile_args(self):
-        if self.args is None:
-            return []
-        return self.args
-
-    def get_link_args(self):
-        return self.libs
 
 class AppleFrameworks(Dependency):
     def __init__(self, environment, kwargs):
@@ -1361,111 +944,6 @@ class AppleFrameworks(Dependency):
     def get_version(self):
         return 'unknown'
 
-class GLDependency(Dependency):
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'gl', kwargs)
-        self.is_found = False
-        self.cargs = []
-        self.linkargs = []
-        if DependencyMethods.PKGCONFIG in self.methods:
-            try:
-                pcdep = PkgConfigDependency('gl', environment, kwargs)
-                if pcdep.found():
-                    self.type_name = 'pkgconfig'
-                    self.is_found = True
-                    self.cargs = pcdep.get_compile_args()
-                    self.linkargs = pcdep.get_link_args()
-                    self.version = pcdep.get_version()
-                    return
-            except Exception:
-                pass
-        if DependencyMethods.SYSTEM in self.methods:
-            if mesonlib.is_osx():
-                self.is_found = True
-                self.linkargs = ['-framework', 'OpenGL']
-                self.version = '1' # FIXME
-                return
-            if mesonlib.is_windows():
-                self.is_found = True
-                self.linkargs = ['-lopengl32']
-                self.version = '1' # FIXME: unfixable?
-                return
-
-    def get_link_args(self):
-        return self.linkargs
-
-    def get_version(self):
-        return self.version
-
-    def get_methods(self):
-        if mesonlib.is_osx() or mesonlib.is_windows():
-            return [DependencyMethods.PKGCONFIG, DependencyMethods.SYSTEM]
-        else:
-            return [DependencyMethods.PKGCONFIG]
-
-# There are three different ways of depending on SDL2:
-# sdl2-config, pkg-config and OSX framework
-class SDL2Dependency(Dependency):
-    def __init__(self, environment, kwargs):
-        Dependency.__init__(self, 'sdl2', kwargs)
-        self.is_found = False
-        self.cargs = []
-        self.linkargs = []
-        if DependencyMethods.PKGCONFIG in self.methods:
-            try:
-                pcdep = PkgConfigDependency('sdl2', environment, kwargs)
-                if pcdep.found():
-                    self.type_name = 'pkgconfig'
-                    self.is_found = True
-                    self.cargs = pcdep.get_compile_args()
-                    self.linkargs = pcdep.get_link_args()
-                    self.version = pcdep.get_version()
-                    return
-            except Exception as e:
-                mlog.debug('SDL 2 not found via pkgconfig. Trying next, error was:', str(e))
-                pass
-        if DependencyMethods.SDLCONFIG in self.methods:
-            sdlconf = shutil.which('sdl2-config')
-            if sdlconf:
-                stdo = Popen_safe(['sdl2-config', '--cflags'])[1]
-                self.cargs = stdo.strip().split()
-                stdo = Popen_safe(['sdl2-config', '--libs'])[1]
-                self.linkargs = stdo.strip().split()
-                stdo = Popen_safe(['sdl2-config', '--version'])[1]
-                self.version = stdo.strip()
-                self.is_found = True
-                mlog.log('Dependency', mlog.bold('sdl2'), 'found:', mlog.green('YES'),
-                         self.version, '(%s)' % sdlconf)
-                return
-            mlog.debug('Could not find sdl2-config binary, trying next.')
-        if DependencyMethods.EXTRAFRAMEWORK in self.methods:
-            if mesonlib.is_osx():
-                fwdep = ExtraFrameworkDependency('sdl2', kwargs.get('required', True), None, kwargs)
-                if fwdep.found():
-                    self.is_found = True
-                    self.cargs = fwdep.get_compile_args()
-                    self.linkargs = fwdep.get_link_args()
-                    self.version = '2' # FIXME
-                    return
-            mlog.log('Dependency', mlog.bold('sdl2'), 'found:', mlog.red('NO'))
-
-    def get_compile_args(self):
-        return self.cargs
-
-    def get_link_args(self):
-        return self.linkargs
-
-    def found(self):
-        return self.is_found
-
-    def get_version(self):
-        return self.version
-
-    def get_methods(self):
-        if mesonlib.is_osx():
-            return [DependencyMethods.PKGCONFIG, DependencyMethods.SDLCONFIG, DependencyMethods.EXTRAFRAMEWORK]
-        else:
-            return [DependencyMethods.PKGCONFIG, DependencyMethods.SDLCONFIG]
 
 class ExtraFrameworkDependency(Dependency):
     def __init__(self, name, required, path, kwargs):
@@ -1796,18 +1274,13 @@ def find_external_dependency(name, environment, kwargs):
     mlog.log('Dependency', mlog.bold(name), 'found:', mlog.red('NO'))
     return pkgdep
 
+
 # This has to be at the end so the classes it references
 # are defined.
 packages = {'boost': BoostDependency,
             'gtest': GTestDependency,
             'gmock': GMockDependency,
-            'qt5': Qt5Dependency,
-            'qt4': Qt4Dependency,
-            'gnustep': GnuStepDependency,
             'appleframeworks': AppleFrameworks,
-            'wxwidgets': WxDependency,
-            'sdl2': SDL2Dependency,
-            'gl': GLDependency,
             'threads': ThreadDependency,
             'python3': Python3Dependency,
             'valgrind': ValgrindDependency,
diff --git a/mesonbuild/dependencies/ui.py b/mesonbuild/dependencies/ui.py
new file mode 100644
index 0000000..3174176
--- /dev/null
+++ b/mesonbuild/dependencies/ui.py
@@ -0,0 +1,560 @@
+# Copyright 2013-2017 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.
+
+# This file contains the detection logic for external dependencies that
+# are UI-related.
+
+import os
+import re
+import shutil
+import subprocess
+from collections import OrderedDict
+
+from .. import mlog
+from .. import mesonlib
+from ..mesonlib import MesonException, Popen_safe, version_compare
+from ..environment import for_windows
+
+from .base import (Dependency, DependencyException, DependencyMethods,
+                   ExternalProgram, ExtraFrameworkDependency, PkgConfigDependency)
+
+
+class GLDependency(Dependency):
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'gl', kwargs)
+        self.is_found = False
+        self.cargs = []
+        self.linkargs = []
+        if DependencyMethods.PKGCONFIG in self.methods:
+            try:
+                pcdep = PkgConfigDependency('gl', environment, kwargs)
+                if pcdep.found():
+                    self.type_name = 'pkgconfig'
+                    self.is_found = True
+                    self.cargs = pcdep.get_compile_args()
+                    self.linkargs = pcdep.get_link_args()
+                    self.version = pcdep.get_version()
+                    return
+            except Exception:
+                pass
+        if DependencyMethods.SYSTEM in self.methods:
+            if mesonlib.is_osx():
+                self.is_found = True
+                self.linkargs = ['-framework', 'OpenGL']
+                self.version = '1'  # FIXME
+                return
+            if mesonlib.is_windows():
+                self.is_found = True
+                self.linkargs = ['-lopengl32']
+                self.version = '1'  # FIXME: unfixable?
+                return
+
+    def get_link_args(self):
+        return self.linkargs
+
+    def get_version(self):
+        return self.version
+
+    def get_methods(self):
+        if mesonlib.is_osx() or mesonlib.is_windows():
+            return [DependencyMethods.PKGCONFIG, DependencyMethods.SYSTEM]
+        else:
+            return [DependencyMethods.PKGCONFIG]
+
+
+class GnuStepDependency(Dependency):
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'gnustep', kwargs)
+        self.required = kwargs.get('required', True)
+        self.modules = kwargs.get('modules', [])
+        self.detect()
+
+    def detect(self):
+        self.confprog = 'gnustep-config'
+        try:
+            gp = Popen_safe([self.confprog, '--help'])[0]
+        except (FileNotFoundError, PermissionError):
+            self.args = None
+            mlog.log('Dependency GnuStep found:', mlog.red('NO'), '(no gnustep-config)')
+            return
+        if gp.returncode != 0:
+            self.args = None
+            mlog.log('Dependency GnuStep found:', mlog.red('NO'))
+            return
+        if 'gui' in self.modules:
+            arg = '--gui-libs'
+        else:
+            arg = '--base-libs'
+        fp, flagtxt, flagerr = Popen_safe([self.confprog, '--objc-flags'])
+        if fp.returncode != 0:
+            raise DependencyException('Error getting objc-args: %s %s' % (flagtxt, flagerr))
+        args = flagtxt.split()
+        self.args = self.filter_arsg(args)
+        fp, libtxt, liberr = Popen_safe([self.confprog, arg])
+        if fp.returncode != 0:
+            raise DependencyException('Error getting objc-lib args: %s %s' % (libtxt, liberr))
+        self.libs = self.weird_filter(libtxt.split())
+        self.version = self.detect_version()
+        mlog.log('Dependency', mlog.bold('GnuStep'), 'found:',
+                 mlog.green('YES'), self.version)
+
+    def weird_filter(self, elems):
+        """When building packages, the output of the enclosing Make
+is sometimes mixed among the subprocess output. I have no idea
+why. As a hack filter out everything that is not a flag."""
+        return [e for e in elems if e.startswith('-')]
+
+    def filter_arsg(self, args):
+        """gnustep-config returns a bunch of garbage args such
+        as -O2 and so on. Drop everything that is not needed."""
+        result = []
+        for f in args:
+            if f.startswith('-D') \
+                    or f.startswith('-f') \
+                    or f.startswith('-I') \
+                    or f == '-pthread' \
+                    or (f.startswith('-W') and not f == '-Wall'):
+                result.append(f)
+        return result
+
+    def detect_version(self):
+        gmake = self.get_variable('GNUMAKE')
+        makefile_dir = self.get_variable('GNUSTEP_MAKEFILES')
+        # This Makefile has the GNUStep version set
+        base_make = os.path.join(makefile_dir, 'Additional', 'base.make')
+        # Print the Makefile variable passed as the argument. For instance, if
+        # you run the make target `print-SOME_VARIABLE`, this will print the
+        # value of the variable `SOME_VARIABLE`.
+        printver = "print-%:\n\t@echo '$($*)'"
+        env = os.environ.copy()
+        # See base.make to understand why this is set
+        env['FOUNDATION_LIB'] = 'gnu'
+        p, o, e = Popen_safe([gmake, '-f', '-', '-f', base_make,
+                              'print-GNUSTEP_BASE_VERSION'],
+                             env=env, write=printver, stdin=subprocess.PIPE)
+        version = o.strip()
+        if not version:
+            mlog.debug("Couldn't detect GNUStep version, falling back to '1'")
+            # Fallback to setting some 1.x version
+            version = '1'
+        return version
+
+    def get_variable(self, var):
+        p, o, e = Popen_safe([self.confprog, '--variable=' + var])
+        if p.returncode != 0 and self.required:
+            raise DependencyException('{!r} for variable {!r} failed to run'
+                                      ''.format(self.confprog, var))
+        return o.strip()
+
+    def found(self):
+        return self.args is not None
+
+    def get_version(self):
+        return self.version
+
+    def get_compile_args(self):
+        if self.args is None:
+            return []
+        return self.args
+
+    def get_link_args(self):
+        return self.libs
+
+
+class QtBaseDependency(Dependency):
+    def __init__(self, name, env, kwargs):
+        Dependency.__init__(self, name, kwargs)
+        self.name = name
+        self.qtname = name.capitalize()
+        self.qtver = name[-1]
+        if self.qtver == "4":
+            self.qtpkgname = 'Qt'
+        else:
+            self.qtpkgname = self.qtname
+        self.root = '/usr'
+        self.bindir = None
+        self.silent = kwargs.get('silent', False)
+        # We store the value of required here instead of passing it on to
+        # PkgConfigDependency etc because we want to try the qmake-based
+        # fallback as well.
+        self.required = kwargs.pop('required', True)
+        kwargs['required'] = False
+        mods = kwargs.get('modules', [])
+        self.cargs = []
+        self.largs = []
+        self.is_found = False
+        if isinstance(mods, str):
+            mods = [mods]
+        if not mods:
+            raise DependencyException('No ' + self.qtname + '  modules specified.')
+        type_text = 'cross' if env.is_cross_build() else 'native'
+        found_msg = '{} {} {{}} dependency (modules: {}) found:' \
+                    ''.format(self.qtname, type_text, ', '.join(mods))
+        from_text = 'pkg-config'
+
+        # Keep track of the detection methods used, for logging purposes.
+        methods = []
+        # Prefer pkg-config, then fallback to `qmake -query`
+        if DependencyMethods.PKGCONFIG in self.methods:
+            self._pkgconfig_detect(mods, env, kwargs)
+            methods.append('pkgconfig')
+        if not self.is_found and DependencyMethods.QMAKE in self.methods:
+            from_text = self._qmake_detect(mods, env, kwargs)
+            methods.append('qmake-' + self.name)
+            methods.append('qmake')
+        if not self.is_found:
+            # Reset compile args and link args
+            self.cargs = []
+            self.largs = []
+            from_text = '(checked {})'.format(mlog.format_list(methods))
+            self.version = 'none'
+            if self.required:
+                err_msg = '{} {} dependency not found {}' \
+                          ''.format(self.qtname, type_text, from_text)
+                raise DependencyException(err_msg)
+            if not self.silent:
+                mlog.log(found_msg.format(from_text), mlog.red('NO'))
+            return
+        from_text = '`{}`'.format(from_text)
+        if not self.silent:
+            mlog.log(found_msg.format(from_text), mlog.green('YES'))
+
+    def compilers_detect(self):
+        "Detect Qt (4 or 5) moc, uic, rcc in the specified bindir or in PATH"
+        if self.bindir:
+            moc = ExternalProgram(os.path.join(self.bindir, 'moc'), silent=True)
+            uic = ExternalProgram(os.path.join(self.bindir, 'uic'), silent=True)
+            rcc = ExternalProgram(os.path.join(self.bindir, 'rcc'), silent=True)
+        else:
+            # We don't accept unsuffixed 'moc', 'uic', and 'rcc' because they
+            # are sometimes older, or newer versions.
+            moc = ExternalProgram('moc-' + self.name, silent=True)
+            uic = ExternalProgram('uic-' + self.name, silent=True)
+            rcc = ExternalProgram('rcc-' + self.name, silent=True)
+        return moc, uic, rcc
+
+    def _pkgconfig_detect(self, mods, env, kwargs):
+        modules = OrderedDict()
+        for module in mods:
+            modules[module] = PkgConfigDependency(self.qtpkgname + module, env, kwargs)
+        self.is_found = True
+        for m in modules.values():
+            if not m.found():
+                self.is_found = False
+                return
+            self.cargs += m.get_compile_args()
+            self.largs += m.get_link_args()
+        self.version = m.modversion
+        # Try to detect moc, uic, rcc
+        if 'Core' in modules:
+            core = modules['Core']
+        else:
+            corekwargs = {'required': 'false', 'silent': 'true'}
+            core = PkgConfigDependency(self.qtpkgname + 'Core', env, corekwargs)
+        # Used by self.compilers_detect()
+        self.bindir = self.get_pkgconfig_host_bins(core)
+        if not self.bindir:
+            # If exec_prefix is not defined, the pkg-config file is broken
+            prefix = core.get_pkgconfig_variable('exec_prefix')
+            if prefix:
+                self.bindir = os.path.join(prefix, 'bin')
+
+    def _find_qmake(self, qmake, env):
+        # Even when cross-compiling, if we don't get a cross-info qmake, we
+        # fallback to using the qmake in PATH because that's what we used to do
+        if env.is_cross_build():
+            qmake = env.cross_info.config['binaries'].get('qmake', qmake)
+        return ExternalProgram(qmake, silent=True)
+
+    def _qmake_detect(self, mods, env, kwargs):
+        for qmake in ('qmake-' + self.name, 'qmake'):
+            self.qmake = self._find_qmake(qmake, env)
+            if not self.qmake.found():
+                continue
+            # Check that the qmake is for qt5
+            pc, stdo = Popen_safe(self.qmake.get_command() + ['-v'])[0:2]
+            if pc.returncode != 0:
+                continue
+            if not 'Qt version ' + self.qtver in stdo:
+                mlog.log('QMake is not for ' + self.qtname)
+                continue
+            # Found qmake for Qt5!
+            break
+        else:
+            # Didn't find qmake :(
+            return
+        self.version = re.search(self.qtver + '(\.\d+)+', stdo).group(0)
+        # Query library path, header path, and binary path
+        mlog.log("Found qmake:", mlog.bold(self.qmake.get_name()), '(%s)' % self.version)
+        stdo = Popen_safe(self.qmake.get_command() + ['-query'])[1]
+        qvars = {}
+        for line in stdo.split('\n'):
+            line = line.strip()
+            if line == '':
+                continue
+            (k, v) = tuple(line.split(':', 1))
+            qvars[k] = v
+        if mesonlib.is_osx():
+            return self._framework_detect(qvars, mods, kwargs)
+        incdir = qvars['QT_INSTALL_HEADERS']
+        self.cargs.append('-I' + incdir)
+        libdir = qvars['QT_INSTALL_LIBS']
+        # Used by self.compilers_detect()
+        self.bindir = self.get_qmake_host_bins(qvars)
+        self.is_found = True
+        for module in mods:
+            mincdir = os.path.join(incdir, 'Qt' + module)
+            self.cargs.append('-I' + mincdir)
+            if for_windows(env.is_cross_build(), env):
+                libfile = os.path.join(libdir, self.qtpkgname + module + '.lib')
+                if not os.path.isfile(libfile):
+                    # MinGW can link directly to .dll
+                    libfile = os.path.join(self.bindir, self.qtpkgname + module + '.dll')
+                    if not os.path.isfile(libfile):
+                        self.is_found = False
+                        break
+            else:
+                libfile = os.path.join(libdir, 'lib{}{}.so'.format(self.qtpkgname, module))
+                if not os.path.isfile(libfile):
+                    self.is_found = False
+                    break
+            self.largs.append(libfile)
+        return qmake
+
+    def _framework_detect(self, qvars, modules, kwargs):
+        libdir = qvars['QT_INSTALL_LIBS']
+        for m in modules:
+            fname = 'Qt' + m
+            fwdep = ExtraFrameworkDependency(fname, kwargs.get('required', True), libdir, kwargs)
+            self.cargs.append('-F' + libdir)
+            if fwdep.found():
+                self.is_found = True
+                self.cargs += fwdep.get_compile_args()
+                self.largs += fwdep.get_link_args()
+        # Used by self.compilers_detect()
+        self.bindir = self.get_qmake_host_bins(qvars)
+
+    def get_qmake_host_bins(self, qvars):
+        # Prefer QT_HOST_BINS (qt5, correct for cross and native compiling)
+        # but fall back to QT_INSTALL_BINS (qt4)
+        if 'QT_HOST_BINS' in qvars:
+            return qvars['QT_HOST_BINS']
+        else:
+            return qvars['QT_INSTALL_BINS']
+
+    def get_version(self):
+        return self.version
+
+    def get_compile_args(self):
+        return self.cargs
+
+    def get_sources(self):
+        return []
+
+    def get_link_args(self):
+        return self.largs
+
+    def get_methods(self):
+        return [DependencyMethods.PKGCONFIG, DependencyMethods.QMAKE]
+
+    def found(self):
+        return self.is_found
+
+    def get_exe_args(self, compiler):
+        # Originally this was -fPIE but nowadays the default
+        # for upstream and distros seems to be -reduce-relocations
+        # which requires -fPIC. This may cause a performance
+        # penalty when using self-built Qt or on platforms
+        # where -fPIC is not required. If this is an issue
+        # for you, patches are welcome.
+        return compiler.get_pic_args()
+
+
+class Qt4Dependency(QtBaseDependency):
+    def __init__(self, env, kwargs):
+        QtBaseDependency.__init__(self, 'qt4', env, kwargs)
+
+    def get_pkgconfig_host_bins(self, core):
+        # Only return one bins dir, because the tools are generally all in one
+        # directory for Qt4, in Qt5, they must all be in one directory. Return
+        # the first one found among the bin variables, in case one tool is not
+        # configured to be built.
+        applications = ['moc', 'uic', 'rcc', 'lupdate', 'lrelease']
+        for application in applications:
+            try:
+                return os.path.dirname(core.get_pkgconfig_variable('%s_location' % application))
+            except MesonException:
+                pass
+
+
+class Qt5Dependency(QtBaseDependency):
+    def __init__(self, env, kwargs):
+        QtBaseDependency.__init__(self, 'qt5', env, kwargs)
+
+    def get_pkgconfig_host_bins(self, core):
+        return core.get_pkgconfig_variable('host_bins')
+
+
+# There are three different ways of depending on SDL2:
+# sdl2-config, pkg-config and OSX framework
+class SDL2Dependency(Dependency):
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'sdl2', kwargs)
+        self.is_found = False
+        self.cargs = []
+        self.linkargs = []
+        if DependencyMethods.PKGCONFIG in self.methods:
+            try:
+                pcdep = PkgConfigDependency('sdl2', environment, kwargs)
+                if pcdep.found():
+                    self.type_name = 'pkgconfig'
+                    self.is_found = True
+                    self.cargs = pcdep.get_compile_args()
+                    self.linkargs = pcdep.get_link_args()
+                    self.version = pcdep.get_version()
+                    return
+            except Exception as e:
+                mlog.debug('SDL 2 not found via pkgconfig. Trying next, error was:', str(e))
+                pass
+        if DependencyMethods.SDLCONFIG in self.methods:
+            sdlconf = shutil.which('sdl2-config')
+            if sdlconf:
+                stdo = Popen_safe(['sdl2-config', '--cflags'])[1]
+                self.cargs = stdo.strip().split()
+                stdo = Popen_safe(['sdl2-config', '--libs'])[1]
+                self.linkargs = stdo.strip().split()
+                stdo = Popen_safe(['sdl2-config', '--version'])[1]
+                self.version = stdo.strip()
+                self.is_found = True
+                mlog.log('Dependency', mlog.bold('sdl2'), 'found:', mlog.green('YES'),
+                         self.version, '(%s)' % sdlconf)
+                return
+            mlog.debug('Could not find sdl2-config binary, trying next.')
+        if DependencyMethods.EXTRAFRAMEWORK in self.methods:
+            if mesonlib.is_osx():
+                fwdep = ExtraFrameworkDependency('sdl2', kwargs.get('required', True), None, kwargs)
+                if fwdep.found():
+                    self.is_found = True
+                    self.cargs = fwdep.get_compile_args()
+                    self.linkargs = fwdep.get_link_args()
+                    self.version = '2'  # FIXME
+                    return
+            mlog.log('Dependency', mlog.bold('sdl2'), 'found:', mlog.red('NO'))
+
+    def get_compile_args(self):
+        return self.cargs
+
+    def get_link_args(self):
+        return self.linkargs
+
+    def found(self):
+        return self.is_found
+
+    def get_version(self):
+        return self.version
+
+    def get_methods(self):
+        if mesonlib.is_osx():
+            return [DependencyMethods.PKGCONFIG, DependencyMethods.SDLCONFIG, DependencyMethods.EXTRAFRAMEWORK]
+        else:
+            return [DependencyMethods.PKGCONFIG, DependencyMethods.SDLCONFIG]
+
+
+class WxDependency(Dependency):
+    wx_found = None
+
+    def __init__(self, environment, kwargs):
+        Dependency.__init__(self, 'wx', kwargs)
+        self.is_found = False
+        # FIXME: use version instead of modversion
+        self.modversion = 'none'
+        if WxDependency.wx_found is None:
+            self.check_wxconfig()
+        if not WxDependency.wx_found:
+            # FIXME: this message could be printed after Dependncy found
+            mlog.log("Neither wx-config-3.0 nor wx-config found; can't detect dependency")
+            return
+
+        # FIXME: This should print stdout and stderr using mlog.debug
+        p, out = Popen_safe([self.wxc, '--version'])[0:2]
+        if p.returncode != 0:
+            mlog.log('Dependency wxwidgets found:', mlog.red('NO'))
+            self.cargs = []
+            self.libs = []
+        else:
+            self.modversion = out.strip()
+            version_req = kwargs.get('version', None)
+            if version_req is not None:
+                if not version_compare(self.modversion, version_req, strict=True):
+                    mlog.log('Wxwidgets version %s does not fullfill requirement %s' %
+                             (self.modversion, version_req))
+                    return
+            mlog.log('Dependency wxwidgets found:', mlog.green('YES'))
+            self.is_found = True
+            self.requested_modules = self.get_requested(kwargs)
+            # wx-config seems to have a cflags as well but since it requires C++,
+            # this should be good, at least for now.
+            p, out = Popen_safe([self.wxc, '--cxxflags'])[0:2]
+            # FIXME: this error should only be raised if required is true
+            if p.returncode != 0:
+                raise DependencyException('Could not generate cargs for wxwidgets.')
+            self.cargs = out.split()
+
+            # FIXME: this error should only be raised if required is true
+            p, out = Popen_safe([self.wxc, '--libs'] + self.requested_modules)[0:2]
+            if p.returncode != 0:
+                raise DependencyException('Could not generate libs for wxwidgets.')
+            self.libs = out.split()
+
+    def get_requested(self, kwargs):
+        modules = 'modules'
+        if modules not in kwargs:
+            return []
+        candidates = kwargs[modules]
+        if isinstance(candidates, str):
+            return [candidates]
+        for c in candidates:
+            if not isinstance(c, str):
+                raise DependencyException('wxwidgets module argument is not a string.')
+        return candidates
+
+    def get_modversion(self):
+        return self.modversion
+
+    def get_version(self):
+        return self.modversion
+
+    def get_compile_args(self):
+        return self.cargs
+
+    def get_link_args(self):
+        return self.libs
+
+    def check_wxconfig(self):
+        for wxc in ['wx-config-3.0', 'wx-config']:
+            try:
+                p, out = Popen_safe([wxc, '--version'])[0:2]
+                if p.returncode == 0:
+                    mlog.log('Found wx-config:', mlog.bold(shutil.which(wxc)),
+                             '(%s)' % out.strip())
+                    self.wxc = wxc
+                    WxDependency.wx_found = True
+                    return
+            except (FileNotFoundError, PermissionError):
+                pass
+        WxDependency.wxconfig_found = False
+        mlog.log('Found wx-config:', mlog.red('NO'))
+
+    def found(self):
+        return self.is_found