meson/build.py

# Copyright 2012-2014 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.

import coredata
import environment
import dependencies
import mlog
import copy, os
from mesonlib import File, flatten

known_basic_kwargs = {'install' : True,
                      'c_pch' : True,
                      'cpp_pch' : True,
                      'c_args' : True,
                      'cpp_args' : True,
                      'cs_args' : True,
                      'vala_args' : True,
                      'link_args' : True,
                      'link_depends': True,
                      'link_with' : True,
                      'include_directories': True,
                      'dependencies' : True,
                      'install_dir' : True,
                      'main_class' : True,
                      'gui_app' : True,
                      'extra_files' : True,
                      'install_rpath' : True,
                      'resources' : True,
                      'sources' : True,
                      'objects' : True,
                      'native' : True,
                     }

known_shlib_kwargs = known_basic_kwargs.copy()
known_shlib_kwargs.update({'version' : True,
                           'soversion' : True})


class InvalidArguments(coredata.MesonException):
    pass

class Build:
    """A class that holds the status of one build including
    all dependencies and so on.
    """

    def __init__(self, environment):
        self.project_name = 'name of master project'
        self.project_version = None
        self.environment = environment
        self.projects = {}
        self.targets = {}
        self.compilers = []
        self.cross_compilers = []
        self.global_args = {}
        self.tests = []
        self.benchmarks = []
        self.headers = []
        self.man = []
        self.data = []
        self.static_linker = None
        self.static_cross_linker = None
        self.pot = []
        self.subprojects = {}
        self.pkgconfig_gens = []
        self.install_scripts = []
        self.install_dirs = []
        self.dep_manifest_name = None
        self.dep_manifest = {}

    def has_language(self, language):
        for i in self.compilers:
            if i.get_language() == language:
                return True
        return False

    def add_compiler(self, compiler):
        if self.static_linker is None and compiler.needs_static_linker():
            self.static_linker = self.environment.detect_static_linker(compiler)
        if self.has_language(compiler.get_language()):
            return
        self.compilers.append(compiler)

    def add_cross_compiler(self, compiler):
        if len(self.cross_compilers) == 0:
            self.static_cross_linker = self.environment.detect_static_linker(compiler)
        for i in self.cross_compilers:
            if i.get_language() == compiler.get_language():
                return
        self.cross_compilers.append(compiler)

    def get_project(self):
        return self.projects['']

    def get_targets(self):
        return self.targets

    def get_tests(self):
        return self.tests

    def get_benchmarks(self):
        return self.benchmarks

    def get_headers(self):
        return self.headers

    def get_man(self):
        return self.man

    def get_data(self):
        return self.data

    def get_install_subdirs(self):
        return self.install_dirs

    def get_global_args(self, compiler):
        return self.global_args.get(compiler.get_language(), [])

class IncludeDirs():
    def __init__(self, curdir, dirs, extra_build_dirs=None):
        self.curdir = curdir
        self.incdirs = dirs
        # Interpreter has validated that all given directories
        # actually exist.
        if extra_build_dirs is None:
            self.extra_build_dirs = []
        else:
            self.extra_build_dirs = extra_build_dirs

    def get_curdir(self):
        return self.curdir

    def get_incdirs(self):
        return self.incdirs

    def get_extra_build_dirs(self):
        return self.extra_build_dirs

class ExtractedObjects():
    def __init__(self, target, srclist):
        self.target = target
        self.srclist = srclist

class BuildTarget():
    def __init__(self, name, subdir, subproject, is_cross, sources, objects, environment, kwargs):
        self.name = name
        self.subdir = subdir
        self.subproject = subproject # Can not be calculated from subdir as subproject dirname can be changed per project.
        self.is_cross = is_cross
        self.sources = []
        self.objects = []
        self.external_deps = []
        self.include_dirs = []
        self.link_targets = []
        self.link_depends = []
        self.filename = 'no_name'
        self.need_install = False
        self.pch = {}
        self.extra_args = {}
        self.generated = []
        self.extra_files = []
        self.process_sourcelist(sources)
        self.process_objectlist(objects)
        self.process_kwargs(kwargs, environment)
        self.check_unknown_kwargs(kwargs)
        if len(self.sources) == 0 and \
            len(self.generated) == 0 and \
            len(self.objects) == 0:
            raise InvalidArguments('Build target %s has no sources.' % name)
        self.validate_sources()

    def get_id(self):
        # This ID must also be a valid file name on all OSs.
        # It should also avoid shell metacharacters for obvious
        # reasons.
        base = self.name + self.type_suffix()
        if self.subproject == '':
            return base
        return self.subproject + '@@' + base

    def check_unknown_kwargs(self, kwargs):
        # Override this method in derived classes that have more
        # keywords.
        self.check_unknown_kwargs_int(kwargs, known_basic_kwargs)

    def check_unknown_kwargs_int(self, kwargs, known_kwargs):
        unknowns = []
        for k in kwargs:
            if not k in known_kwargs:
                unknowns.append(k)
        if len(unknowns) > 0:
            mlog.log(mlog.bold('Warning:'), 'Unknown keyword argument(s) in target %s: %s.' %
                     (self.name, ', '.join(unknowns)))

    def process_objectlist(self, objects):
        assert(isinstance(objects, list))
        for s in objects:
            if hasattr(s, 'held_object'):
                s = s.held_object
            if isinstance(s, str):
                self.objects.append(s)
            elif isinstance(s, ExtractedObjects):
                self.objects.append(s)
            else:
                raise InvalidArguments('Bad object in target %s.' % self.name)

    def process_sourcelist(self, sources):
        if not isinstance(sources, list):
            sources = [sources]
        added_sources = {} # If the same source is defined multiple times, use it only once.
        for s in sources:
            # Holder unpacking. Ugly.
            if hasattr(s, 'held_object'):
                s = s.held_object
            if isinstance(s, File):
                if not s in added_sources:
                    self.sources.append(s)
                    added_sources[s] = True
            elif isinstance(s, GeneratedList) or isinstance(s, CustomTarget):
                self.generated.append(s)
            else:
                raise InvalidArguments('Bad source in target %s.' % self.name)

    def validate_sources(self):
        if len(self.sources) > 0:
            firstname = self.sources[0]
            if isinstance(firstname, File):
                firstname = firstname.fname
            first = os.path.split(firstname)[1]
            (base, suffix) = os.path.splitext(first)
            if suffix == '.rs':
                if self.name != base:
                    raise InvalidArguments('In Rust targets, the first source file must be named projectname.rs.')

    def get_original_kwargs(self):
        return self.kwargs

    def unpack_holder(self, d):
        if not isinstance(d, list):
            d = [d]
        newd = []
        for i in d:
            if hasattr(i, 'held_object'):
                newd.append(i.held_object)
            else:
                newd.append(i)
        return newd

    def copy_kwargs(self, kwargs):
        self.kwargs = copy.copy(kwargs)
        # This sucks quite badly. Arguments
        # are holders but they can't be pickled
        # so unpack those known.
        if 'dependencies' in self.kwargs:
            self.kwargs['dependencies'] = self.unpack_holder(self.kwargs['dependencies'])
        if 'link_with' in self.kwargs:
            self.kwargs['link_with'] = self.unpack_holder(self.kwargs['link_with'])

    def extract_objects(self, srcargs):
        obj_src = []
        for srclist in srcargs:
            if not isinstance(srclist, list):
                srclist = [srclist]
            for src in srclist:
                if not isinstance(src, str):
                    raise coredata.MesonException('Extraction arguments must be strings.')
                src = File(False, self.subdir, src)
                if src not in self.sources:
                    raise coredata.MesonException('Tried to extract unknown source %s.' % src)
                obj_src.append(src)
        return ExtractedObjects(self, obj_src)

    def extract_all_objects(self):
        return ExtractedObjects(self, self.sources)

    def get_all_link_deps(self):
        return self.get_transitive_link_deps()

    def get_transitive_link_deps(self):
        result = []
        for i in self.link_targets:
            result += i.get_all_link_deps()
        return result

    def get_custom_install_dir(self):
        return self.custom_install_dir

    def process_kwargs(self, kwargs, environment):
        self.copy_kwargs(kwargs)
        kwargs.get('modules', [])
        self.need_install = kwargs.get('install', self.need_install)
        llist = kwargs.get('link_with', [])
        if not isinstance(llist, list):
            llist = [llist]
        for linktarget in llist:
            # Sorry for this hack. Keyword targets are kept in holders
            # in kwargs. Unpack here without looking at the exact type.
            if hasattr(linktarget, "held_object"):
                linktarget = linktarget.held_object
            self.link(linktarget)
        c_pchlist = kwargs.get('c_pch', [])
        if not isinstance(c_pchlist, list):
            c_pchlist = [c_pchlist]
        self.add_pch('c', c_pchlist)
        cpp_pchlist = kwargs.get('cpp_pch', [])
        if not isinstance(cpp_pchlist, list):
            cpp_pchlist = [cpp_pchlist]
        self.add_pch('cpp', cpp_pchlist)
        clist = kwargs.get('c_args', [])
        if not isinstance(clist, list):
            clist = [clist]
        self.add_compiler_args('c', clist)
        cpplist = kwargs.get('cpp_args', [])
        if not isinstance(cpplist, list):
            cpplist = [cpplist]
        self.add_compiler_args('cpp', cpplist)
        cslist = kwargs.get('cs_args', [])
        if not isinstance(cslist, list):
            cslist = [cslist]
        self.add_compiler_args('cs', cslist)
        valalist = kwargs.get('vala_args', [])
        if not isinstance(valalist, list):
            valalist = [valalist]
        self.add_compiler_args('vala', valalist)
        self.link_args = kwargs.get('link_args', [])
        if not isinstance(self.link_args, list):
            self.link_args = [self.link_args]
        for i in self.link_args:
            if not isinstance(i, str):
                raise InvalidArguments('Link_args arguments must be strings.')
        self.link_depends = kwargs.get('link_depends', [])
        if not isinstance(self.link_depends, list):
            self.link_depends = [self.link_depends]
        for i in self.link_depends:
            if not isinstance(i, str):
                raise InvalidArguments('Link_depends arguments must be strings.')
        inclist = kwargs.get('include_directories', [])
        if not isinstance(inclist, list):
            inclist = [inclist]
        self.add_include_dirs(inclist)
        deplist = kwargs.get('dependencies', [])
        if not isinstance(deplist, list):
            deplist = [deplist]
        self.add_external_deps(deplist)
        self.custom_install_dir = kwargs.get('install_dir', None)
        if self.custom_install_dir is not None:
            if not isinstance(self.custom_install_dir, str):
                raise InvalidArguments('Custom_install_dir must be a string')
        main_class = kwargs.get('main_class', '')
        if not isinstance(main_class, str):
            raise InvalidArguments('Main class must be a string')
        self.main_class = main_class
        if isinstance(self, Executable):
            self.gui_app = kwargs.get('gui_app', False)
            if not isinstance(self.gui_app, bool):
                raise InvalidArguments('Argument gui_app must be boolean.')
        elif 'gui_app' in kwargs:
            raise InvalidArguments('Argument gui_app can only be used on executables.')
        extra_files = kwargs.get('extra_files', [])
        if isinstance(extra_files, str):
            extra_files = [extra_files]
        for i in extra_files:
            if not isinstance(i, str):
                raise InvalidArguments('Arguments to extra_files must be strings.')
            trial = os.path.join(environment.get_source_dir(), self.subdir, i)
            if not(os.path.isfile(trial)):
                raise InvalidArguments('Tried to add non-existing extra file %s.' % i)
        self.extra_files = extra_files
        self.install_rpath = kwargs.get('install_rpath', '')
        if not isinstance(self.install_rpath, str):
            raise InvalidArguments('Install_rpath is not a string.')
        resources = kwargs.get('resources', [])
        if not isinstance(resources, list):
            resources = [resources]
        for r in resources:
            if not isinstance(r, str):
                raise InvalidArguments('Resource argument is not a string.')
            trial = os.path.join(environment.get_source_dir(), self.subdir, r)
            if not os.path.isfile(trial):
                raise InvalidArguments('Tried to add non-existing resource %s.' % r)
        self.resources = resources

    def get_subdir(self):
        return self.subdir

    def get_filename(self):
        return self.filename

    def get_extra_args(self, language):
        return self.extra_args.get(language, [])

    def get_dependencies(self):
        transitive_deps = []
        for t in self.link_targets:
            transitive_deps.append(t)
            if isinstance(t, StaticLibrary):
                transitive_deps += t.get_dependencies()
        return transitive_deps

    def get_basename(self):
        return self.name

    def get_source_subdir(self):
        return self.subdir

    def get_sources(self):
        return self.sources

    def get_objects(self):
        return self.objects

    def get_generated_sources(self):
        return self.generated

    def should_install(self):
        return self.need_install

    def has_pch(self):
        return len(self.pch) > 0

    def get_pch(self, language):
        try:
            return self.pch[language]
        except KeyError:
            return[]

    def get_include_dirs(self):
        return self.include_dirs

    def add_external_deps(self, deps):
        if not isinstance(deps, list):
            deps = [deps]
        for dep in deps:
            if hasattr(dep, 'held_object'):
                dep = dep.held_object
            if isinstance(dep, dependencies.InternalDependency):
                self.process_sourcelist(dep.sources)
                self.add_include_dirs(dep.include_directories)
                for l in dep.libraries:
                    self.link(l)
                self.add_external_deps(dep.ext_deps)
            elif isinstance(dep, dependencies.Dependency):
                self.external_deps.append(dep)
                self.process_sourcelist(dep.get_sources())
            else:
                raise InvalidArguments('Argument is not an external dependency')

    def get_external_deps(self):
        return self.external_deps

    def link(self, target):
        if not isinstance(target, list):
            target = [target]
        for t in target:
            if hasattr(t, 'held_object'):
                t = t.held_object
            if not isinstance(t, StaticLibrary) and \
            not isinstance(t, SharedLibrary):
                raise InvalidArguments('Link target is not library.')
            if self.is_cross != t.is_cross:
                raise InvalidArguments('Tried to mix cross built and native libraries in target %s.' % self.name)
            self.link_targets.append(t)

    def set_generated(self, genlist):
        for g in genlist:
            if not(isinstance(g, GeneratedList)):
                raise InvalidArguments('Generated source argument is not the output of a generator.')
            self.generated.append(g)

    def add_pch(self, language, pchlist):
        if len(pchlist) == 0:
            return
        elif len(pchlist) == 1:
            if not environment.is_header(pchlist[0]):
                raise InvalidArguments('Pch argument %s is not a header.' % pchlist[0])
        elif len(pchlist) == 2:
            if environment.is_header(pchlist[0]):
                if not environment.is_source(pchlist[1]):
                    raise InvalidArguments('PCH definition must contain one header and at most one source.')
            elif environment.is_source(pchlist[0]):
                if not environment.is_header(pchlist[1]):
                    raise InvalidArguments('PCH definition must contain one header and at most one source.')
                pchlist = [pchlist[1], pchlist[0]]
            else:
                raise InvalidArguments('PCH argument %s is of unknown type.' % pchlist[0])
        elif len(pchlist) > 2:
            raise InvalidArguments('PCH definition may have a maximum of 2 files.')
        self.pch[language] = pchlist

    def add_include_dirs(self, args):
        ids = []
        for a in args:
            # FIXME same hack, forcibly unpack from holder.
            if hasattr(a, 'held_object'):
                a = a.held_object
            if not isinstance(a, IncludeDirs):
                raise InvalidArguments('Include directory to be added is not an include directory object.')
            ids.append(a)
        self.include_dirs += ids

    def add_compiler_args(self, language, args):
        args = flatten(args)
        for a in args:
            if not isinstance(a, (str, File)):
                raise InvalidArguments('A non-string passed to compiler args.')
        if language in self.extra_args:
            self.extra_args[language] += args
        else:
            self.extra_args[language] = args

    def get_aliaslist(self):
        return []


class Generator():
    def __init__(self, args, kwargs):
        if len(args) != 1:
            raise InvalidArguments('Generator requires one and only one positional argument')
        
        exe = args[0]
        if hasattr(exe, 'held_object'):
            exe = exe.held_object
        if not isinstance(exe, Executable) and not isinstance(exe, dependencies.ExternalProgram):
            raise InvalidArguments('First generator argument must be an executable.')
        self.exe = exe
        self.process_kwargs(kwargs)

    def get_exe(self):
        return self.exe

    def process_kwargs(self, kwargs):
        if 'arguments' not in kwargs:
            raise InvalidArguments('Generator must have "arguments" keyword argument.')
        args = kwargs['arguments']
        if isinstance(args, str):
            args = [args]
        if not isinstance(args, list):
            raise InvalidArguments('"Arguments" keyword argument must be a string or a list of strings.')
        for a in args:
            if not isinstance(a, str):
                raise InvalidArguments('A non-string object in "arguments" keyword argument.')
        self.arglist = args

        if 'output' not in kwargs:
            raise InvalidArguments('Generator must have "output" keyword argument.')
        outputs = kwargs['output']
        if not isinstance(outputs, list):
            outputs = [outputs]
        for rule in outputs:
            if not isinstance(rule, str):
                raise InvalidArguments('"output" may only contain strings.')
            if not '@BASENAME@' in rule and not '@PLAINNAME@' in rule:
                raise InvalidArguments('Every element of "output" must contain @BASENAME@ or @PLAINNAME@.')
            if '/' in rule or '\\' in rule:
                raise InvalidArguments('"outputs" must not contain a directory separator.')
        if len(outputs) > 1:
            for o in outputs:
                if '@OUTPUT@' in o:
                    raise InvalidArguments('Tried to use @OUTPUT@ in a rule with more than one output.')
        self.outputs = outputs

    def get_base_outnames(self, inname):
        plainname = os.path.split(inname)[1]
        basename = plainname.split('.')[0]
        return [x.replace('@BASENAME@', basename).replace('@PLAINNAME@', plainname) for x in self.outputs]

    def get_arglist(self):
        return self.arglist

class GeneratedList():
    def __init__(self, generator, extra_args=[]):
        if hasattr(generator, 'held_object'):
            generator = generator.held_object
        self.generator = generator
        self.infilelist = []
        self.outfilelist = []
        self.outmap = {}
        self.extra_depends = []
        self.extra_args = extra_args

    def add_file(self, newfile):
        self.infilelist.append(newfile)
        outfiles = self.generator.get_base_outnames(newfile)
        self.outfilelist += outfiles
        self.outmap[newfile] = outfiles

    def get_infilelist(self):
        return self.infilelist

    def get_outfilelist(self):
        return self.outfilelist

    def get_outputs_for(self, filename):
        return self.outmap[filename]

    def get_generator(self):
        return self.generator

    def get_extra_args(self):
        return self.extra_args

class Executable(BuildTarget):
    def __init__(self, name, subdir, subproject, is_cross, sources, objects, environment, kwargs):
        super().__init__(name, subdir, subproject, is_cross, sources, objects, environment, kwargs)
        self.prefix = ''
        self.suffix = environment.get_exe_suffix()
        suffix = environment.get_exe_suffix()
        if len(self.sources) > 0 and self.sources[0].endswith('.cs'):
            suffix = 'exe'
        if suffix != '':
            self.filename = self.name + '.' + suffix
        else:
            self.filename = self.name

    def type_suffix(self):
        return "@exe"

class StaticLibrary(BuildTarget):
    def __init__(self, name, subdir, subproject, is_cross, sources, objects, environment, kwargs):
        super().__init__(name, subdir, subproject, is_cross, sources, objects, environment, kwargs)
        if len(self.sources) > 0 and self.sources[0].endswith('.cs'):
            raise InvalidArguments('Static libraries not supported for C#.')
        self.prefix = environment.get_static_lib_prefix()
        self.suffix = environment.get_static_lib_suffix()
        if len(self.sources) > 0 and self.sources[0].endswith('.rs'):
            self.suffix = 'rlib'
        self.filename = self.prefix + self.name + '.' + self.suffix

    def get_import_filename(self):
        return self.filename

    def get_osx_filename(self):
        return self.get_filename()

    def type_suffix(self):
        return "@sta"

class SharedLibrary(BuildTarget):
    def __init__(self, name, subdir, subproject, is_cross, sources, objects, environment, kwargs):
        self.version = None
        self.soversion = None
        super().__init__(name, subdir, subproject, is_cross, sources, objects, environment, kwargs);
        if len(self.sources) > 0 and self.sources[0].endswith('.cs'):
            self.suffix = 'dll'
            self.prefix = 'lib'
        else:
            self.prefix = environment.get_shared_lib_prefix()
            self.suffix = environment.get_shared_lib_suffix()
        if len(self.sources) > 0 and self.sources[0].endswith('.rs'):
            self.suffix = 'rlib'
        self.importsuffix = environment.get_import_lib_suffix()
        self.filename = self.prefix + self.name + '.' + self.suffix

    def process_kwargs(self, kwargs, environment):
        super().process_kwargs(kwargs, environment)
        if 'version' in kwargs:
            self.set_version(kwargs['version'])
        if 'soversion' in kwargs:
            self.set_soversion(kwargs['soversion'])

    def check_unknown_kwargs(self, kwargs):
        self.check_unknown_kwargs_int(kwargs, known_shlib_kwargs)

    def get_shbase(self):
        return self.prefix + self.name + '.' + self.suffix

    def get_import_filename(self):
        return self.prefix + self.name + '.' + self.importsuffix

    def get_all_link_deps(self):
        return [self] + self.get_transitive_link_deps()

    def get_filename(self):
        '''Works on all platforms except OSX, which does its own thing.'''
        fname = self.get_shbase()
        if self.version is None:
            return fname
        else:
            return fname + '.' + self.version

    def get_osx_filename(self):
        if self.version is None:
            return self.get_shbase()
        return self.prefix + self.name + '.' + self.version + '.' + self.suffix

    def set_version(self, version):
        if not isinstance(version, str):
            raise InvalidArguments('Shared library version is not a string.')
        self.version = version

    def set_soversion(self, version):
        if isinstance(version, int):
            version = str(version)
        if not isinstance(version, str):
            raise InvalidArguments('Shared library soversion is not a string or integer.')
        self.soversion = version

    def get_aliaslist(self):
        aliases = []
        if self.soversion is not None:
            aliases.append(self.get_shbase() + '.' + self.soversion)
        if self.version is not None:
            aliases.append(self.get_shbase())
        return aliases

    def type_suffix(self):
        return "@sha"

class CustomTarget:
    known_kwargs = {'input' : True,
                    'output' : True,
                    'command' : True,
                    'install' : True,
                    'install_dir' : True,
                    'build_always' : True,
                    'depends' : True,
                    'depend_files' : True,
                    }

    def __init__(self, name, subdir, kwargs):
        self.name = name
        self.subdir = subdir
        self.dependencies = []
        self.extra_depends = []
        self.depend_files = [] # Files that this target depends on but are not on the command line.
        self.process_kwargs(kwargs)
        self.extra_files = []
        self.install_rpath = ''
        unknowns = []
        for k in kwargs:
            if k not in CustomTarget.known_kwargs:
                unknowns.append(k)
        if len(unknowns) > 0:
            mlog.log(mlog.bold('Warning:'), 'Unknown keyword arguments in target %s: %s' %
                     (self.name, ', '.join(unknowns)))

    def get_id(self):
        return self.name + self.type_suffix()

    def process_kwargs(self, kwargs):
        self.sources = kwargs.get('input', [])
        if not isinstance(self.sources, list):
            self.sources = [self.sources]
        if 'output' not in kwargs:
            raise InvalidArguments('Missing keyword argument "output".')
        self.output = kwargs['output']
        if not isinstance(self.output, list):
            self.output = [self.output]
        for i in self.output:
            if not(isinstance(i, str)):
                raise InvalidArguments('Output argument not a string.')
            if '/' in i:
                raise InvalidArguments('Output must not contain a path segment.')
        if 'command' not in kwargs:
            raise InvalidArguments('Missing keyword argument "command".')
        cmd = kwargs['command']
        if not(isinstance(cmd, list)):
            cmd = [cmd]
        final_cmd = []
        for i, c in enumerate(cmd):
            if hasattr(c, 'held_object'):
                c = c.held_object
            if isinstance(c, str):
                final_cmd.append(c)
            elif isinstance(c, dependencies.ExternalProgram):
                final_cmd += c.get_command()
            elif isinstance(c, BuildTarget) or isinstance(c, CustomTarget):
                self.dependencies.append(c)
                final_cmd.append(c)
            elif isinstance(c, list):
                # Hackety hack, only supports one level of flattening. Should really
                # work to arbtrary depth.
                for s in c:
                    if not isinstance(s, str):
                        raise InvalidArguments('Array as argument %d contains a non-string.' % i)
                    final_cmd.append(s)
            else:
                raise InvalidArguments('Argument %s in "command" is invalid.' % i)
        self.command = final_cmd
        if 'install' in kwargs:
            self.install = kwargs['install']
            if not isinstance(self.install, bool):
                raise InvalidArguments('"install" must be boolean.')
            if 'install_dir' not in kwargs:
                raise InvalidArguments('"install_dir" not specified.')
            self.install_dir = kwargs['install_dir']
            if not(isinstance(self.install_dir, str)):
                raise InvalidArguments('"install_dir" must be a string.')
        else:
            self.install = False
        self.build_always = kwargs.get('build_always', False)
        if not isinstance(self.build_always, bool):
            raise InvalidArguments('Argument build_always must be a boolean.')
        extra_deps = kwargs.get('depends', [])
        if not isinstance(extra_deps, list):
            extra_deps = [extra_deps]
        for ed in extra_deps:
            while hasattr(ed, 'held_object'):
                ed = ed.held_object
            if not isinstance(ed, CustomTarget) and not isinstance(ed, BuildTarget):
                raise InvalidArguments('Can only depend on toplevel targets.')
            self.extra_depends.append(ed)
        depend_files = kwargs.get('depend_files', [])
        if not isinstance(depend_files, list):
            depend_files = [depend_files]
        for i in depend_files:
            if isinstance(i, (File, str)):
                self.depend_files.append(i)
            else:
                mlog.debug(i)
                raise InvalidArguments('Unknown type in depend_files.')

    def get_basename(self):
        return self.name

    def get_dependencies(self):
        return self.dependencies

    def should_install(self):
        return self.install

    def get_custom_install_dir(self):
        return self.install_dir

    def get_subdir(self):
        return self.subdir

    def get_filename(self):
        return self.output

    def get_aliaslist(self):
        return []

    def get_sources(self):
        return self.sources

    def get_generated_sources(self):
        return []

    def type_suffix(self):
        return "@cus"

class RunTarget:
    def __init__(self, name, command, args, subdir):
        self.name = name
        self.command = command
        self.args = args
        self.subdir = subdir

    def get_id(self):
        return self.name + self.type_suffix()

    def get_basename(self):
        return self.name

    def get_dependencies(self):
        return []

    def get_generated_sources(self):
        return []

    def get_sources(self):
        return []

    def get_subdir(self):
        return self.subdir

    def should_install(self):
        return False

    def get_filename(self):
        return self.name

    def type_suffix(self):
        return "@run"

class Jar(BuildTarget):
    def __init__(self, name, subdir, subproject, is_cross, sources, objects, environment, kwargs):
        super().__init__(name, subdir, subproject, is_cross, sources, objects, environment, kwargs);
        for s in self.sources:
            if not s.endswith('.java'):
                raise InvalidArguments('Jar source %s is not a java file.' % s)
        self.filename = self.name + '.jar'

    def get_main_class(self):
        return self.main_class

    def type_suffix(self):
        return "@jar"

class ConfigureFile():

    def __init__(self, subdir, sourcename, targetname, configuration_data):
        self.subdir = subdir
        self.sourcename = sourcename
        self.targetname = targetname
        self.configuration_data = configuration_data

    def get_configuration_data(self):
        return self.configuration_data

    def get_subdir(self):
        return self.subdir

    def get_source_name(self):
        return self.sourcename

    def get_target_name(self):
        return self.targetname

class ConfigurationData():
    def __init__(self):
        super().__init__()
        self.values = {}

    def get(self, name):
        return self.values[name]

    def keys(self):
        return self.values.keys()

class PkgConfigGenerator():
    def __init__(self, libraries, subdirs, name, description, version, filebase):
        self.libraries = []
        for l in libraries:
            if hasattr(l, 'held_object'):
                self.libraries.append(l.held_object)
            else:
                self.libraries.append(l)
        self.headerdirs = {}
        self.subdirs = subdirs
        self.name = name
        self.description = description
        self.version = version
        self.filebase = filebase

class InstallScript:
    def __init__(self, cmd_arr):
        assert(isinstance(cmd_arr, list))
        self.cmd_arr = cmd_arr