meson/mesonbuild/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.

from . import coredata
from . import environment
from . import dependencies
from . import mlog
import copy, os, re
from .mesonlib import File, flatten, MesonException
from .environment import for_windows, for_darwin

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,
                           'name_prefix' : True,
                           'name_suffix' : True,
                           'vs_module_defs' : True})

def sources_are_suffix(sources, suffix):
    for source in sources:
        if source.endswith('.' + suffix):
            return True
    return False

def compiler_is_msvc(sources, is_cross, env):
    """
    Since each target does not currently have the compiler information attached
    to it, we must do this detection manually here.

    This detection is purposely incomplete and will cause bugs if other code is
    extended and this piece of code is forgotten.
    """
    compiler = None
    if sources_are_suffix(sources, 'c'):
        try:
            compiler = env.detect_c_compiler(is_cross)
        except MesonException:
            return False
    elif sources_are_suffix(sources, 'cxx') or \
         sources_are_suffix(sources, 'cpp') or \
         sources_are_suffix(sources, 'cc'):
        try:
            compiler = env.detect_cpp_compiler(is_cross)
        except MesonException:
            return False
    if compiler and compiler.get_id() == 'msvc':
        return True
    return False


class InvalidArguments(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.global_link_args = {}
        self.tests = []
        self.benchmarks = []
        self.headers = []
        self.man = []
        self.data = []
        self.static_linker = None
        self.static_cross_linker = None
        self.subprojects = {}
        self.install_scripts = []
        self.postconf_scripts = []
        self.install_dirs = []
        self.dep_manifest_name = None
        self.dep_manifest = {}
        self.cross_stdlibs = {}

    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(), [])

    def get_global_link_args(self, compiler):
        return self.global_link_args.get(compiler.get_language(), [])

class IncludeDirs():
    def __init__(self, curdir, dirs, is_system, extra_build_dirs=None):
        self.curdir = curdir
        self.incdirs = dirs
        self.is_system = is_system
        # 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 __repr__(self):
        repr_str = "<{0} {1}: {2}>"
        return repr_str.format(self.__class__.__name__, self.get_id(), self.filename)

    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)
            elif isinstance(s, GeneratedList) or isinstance(s, CustomTarget):
                msg =  'Generated files are not allowed in the \'objects\' kwarg ' + \
                    'for target {!r}.\nIt is meant only for '.format(self.name) + \
                    'pre-built object files that are shipped with the\nsource ' + \
                    'tree. Try adding it in the list of sources.'
                raise InvalidArguments(msg)
            else:
                msg = 'Bad object of type {!r} in target {!r}.'.format(type(s).__name__, self.name)
                raise InvalidArguments(msg)

    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:
                msg = 'Bad source of type {!r} in target {!r}.'.format(type(s).__name__, self.name)
                raise InvalidArguments(msg)

    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 MesonException('Extraction arguments must be strings.')
                src = File(False, self.subdir, src)
                if src not in self.sources:
                    raise 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
        if 'name_prefix' in kwargs:
            name_prefix = kwargs['name_prefix']
            if isinstance(name_prefix, list):
                if len(name_prefix) != 0:
                    raise InvalidArguments('Array must be empty to signify null.')
            elif not isinstance(name_prefix, str):
                raise InvalidArguments('Name prefix must be a string.')
            self.prefix = name_prefix
        if 'name_suffix' in kwargs:
            name_suffix = kwargs['name_suffix']
            if isinstance(name_suffix, list):
                if len(name_suffix) != 0:
                    raise InvalidArguments('Array must be empty to signify null.')
            else:
                if not isinstance(name_suffix, str):
                    raise InvalidArguments('Name suffix must be a string.')
                self.suffix = name_suffix

    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):
                # Those parts that are internal.
                self.process_sourcelist(dep.sources)
                self.add_include_dirs(dep.include_directories)
                for l in dep.libraries:
                    self.link(l)
                # Those parts that are external.
                extpart = dependencies.InternalDependency('undefined',
                                                          [],
                                                          dep.compile_args,
                                                          dep.link_args,
                                                          [], [], [])
                self.external_deps.append(extpart)
                # Deps of deps.
                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 __repr__(self):
        repr_str = "<{0}: {1}>"
        return repr_str.format(self.__class__.__name__, self.exe)

    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)
        # Unless overriden, executables have no suffix or prefix. Except on
        # Windows and with C#/Mono executables where the suffix is 'exe'
        if not hasattr(self, 'prefix'):
            self.prefix = ''
        if not hasattr(self, 'suffix'):
            # Executable for Windows or C#/Mono
            if for_windows(is_cross, environment) or sources_are_suffix(self.sources, 'cs'):
                self.suffix = 'exe'
            else:
                self.suffix = ''
        self.filename = self.name
        if self.suffix:
            self.filename += '.' + self.suffix

    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 sources_are_suffix(self.sources, 'cs'):
            raise InvalidArguments('Static libraries not supported for C#.')
        # By default a static library is named libfoo.a even on Windows because
        # MSVC does not have a consistent convention for what static libraries
        # are called. The MSVC CRT uses libfoo.lib syntax but nothing else uses
        # it and GCC only looks for static libraries called foo.lib and
        # libfoo.a. However, we cannot use foo.lib because that's the same as
        # the import library. Using libfoo.a is ok because people using MSVC
        # always pass the library filename while linking anyway.
        if not hasattr(self, 'prefix'):
            self.prefix = 'lib'
        if not hasattr(self, 'suffix'):
            # Rust static library crates have .rlib suffix
            if sources_are_suffix(self.sources, 'rs'):
                self.suffix = 'rlib'
            else:
                self.suffix = 'a'
        self.filename = self.prefix + self.name + '.' + self.suffix

    def type_suffix(self):
        return "@sta"

class SharedLibrary(BuildTarget):
    def __init__(self, name, subdir, subproject, is_cross, sources, objects, environment, kwargs):
        self.soversion = None
        self.ltversion = None
        self.vs_module_defs = None
        # The import library this target will generate
        self.import_filename = None
        # The import library that Visual Studio would generate (and accept)
        self.vs_import_filename = None
        # The import library that GCC would generate (and prefer)
        self.gcc_import_filename = None
        super().__init__(name, subdir, subproject, is_cross, sources, objects, environment, kwargs)
        if not hasattr(self, 'prefix'):
            self.prefix = None
        if not hasattr(self, 'suffix'):
            self.suffix = None
        self.basic_filename_tpl = '{0.prefix}{0.name}.{0.suffix}'
        self.determine_filenames(is_cross, environment)

    def determine_filenames(self, is_cross, env):
        """
        See https://github.com/mesonbuild/meson/pull/417 for details.

        First we determine the filename template (self.filename_tpl), then we
        set the output filename (self.filename).

        The template is needed while creating aliases (self.get_aliaslist),
        which are needed while generating .so shared libraries for Linux.

        Besides this, there's also the import library name, which is only used
        on Windows since on that platform the linker uses a separate library
        called the "import library" during linking instead of the shared
        library (DLL). The toolchain will output an import library in one of
        two formats: GCC or Visual Studio.

        When we're building with Visual Studio, the import library that will be
        generated by the toolchain is self.vs_import_filename, and with
        MinGW/GCC, it's self.gcc_import_filename. self.import_filename will
        always contain the import library name this target will generate.
        """
        prefix = ''
        suffix = ''
        self.filename_tpl = self.basic_filename_tpl
        # If the user already provided the prefix and suffix to us, we don't
        # need to do any filename suffix/prefix detection.
        # NOTE: manual prefix/suffix override is currently only tested for C/C++
        if self.prefix != None and self.suffix != None:
            pass
        # C# and Mono
        elif sources_are_suffix(self.sources, 'cs'):
            prefix = ''
            suffix = 'dll'
            self.filename_tpl = '{0.prefix}{0.name}.{0.suffix}'
        # Rust
        elif sources_are_suffix(self.sources, 'rs'):
            # Currently, we always build --crate-type=rlib
            prefix = 'lib'
            suffix = 'rlib'
            self.filename_tpl = '{0.prefix}{0.name}.{0.suffix}'
        # C, C++, Swift, Vala
        # Only Windows uses a separate import library for linking
        # For all other targets/platforms import_filename stays None
        elif for_windows(is_cross, env):
            suffix = 'dll'
            self.vs_import_filename = '{0}.lib'.format(self.name)
            self.gcc_import_filename = 'lib{0}.dll.a'.format(self.name)
            if compiler_is_msvc(self.sources, is_cross, env):
                # Shared library is of the form foo.dll
                prefix = ''
                # Import library is called foo.lib
                self.import_filename = self.vs_import_filename
            # Assume GCC-compatible naming
            else:
                # Shared library is of the form libfoo.dll
                prefix = 'lib'
                # Import library is called libfoo.dll.a
                self.import_filename = self.gcc_import_filename
            # Shared library has the soversion if it is defined
            if self.soversion:
                self.filename_tpl = '{0.prefix}{0.name}-{0.soversion}.{0.suffix}'
            else:
                self.filename_tpl = '{0.prefix}{0.name}.{0.suffix}'
        elif for_darwin(is_cross, env):
            prefix = 'lib'
            suffix = 'dylib'
            if self.soversion:
                # libfoo.X.dylib
                self.filename_tpl = '{0.prefix}{0.name}.{0.soversion}.{0.suffix}'
            else:
                # libfoo.dylib
                self.filename_tpl = '{0.prefix}{0.name}.{0.suffix}'
        else:
            prefix = 'lib'
            suffix = 'so'
            if self.ltversion:
                # libfoo.so.X[.Y[.Z]] (.Y and .Z are optional)
                self.filename_tpl = '{0.prefix}{0.name}.{0.suffix}.{0.ltversion}'
            elif self.soversion:
                # libfoo.so.X
                self.filename_tpl = '{0.prefix}{0.name}.{0.suffix}.{0.soversion}'
            else:
                # No versioning, libfoo.so
                self.filename_tpl = '{0.prefix}{0.name}.{0.suffix}'
        if self.prefix == None:
            self.prefix = prefix
        if self.suffix == None:
            self.suffix = suffix
        self.filename = self.filename_tpl.format(self)

    def process_kwargs(self, kwargs, environment):
        super().process_kwargs(kwargs, environment)
        # Shared library version
        if 'version' in kwargs:
            self.ltversion = kwargs['version']
            if not isinstance(self.ltversion, str):
                raise InvalidArguments('Shared library version needs to be a string, not ' + type(self.ltversion).__name__)
            if not re.fullmatch(r'[0-9]+(\.[0-9]+){0,2}', self.ltversion):
                raise InvalidArguments('Invalid Shared library version "{0}". Must be of the form X.Y.Z where all three are numbers. Y and Z are optional.'.format(self.ltversion))
        # Try to extract/deduce the soversion
        if 'soversion' in kwargs:
            self.soversion = kwargs['soversion']
            if isinstance(self.soversion, int):
                self.soversion = str(self.soversion)
            if not isinstance(self.soversion, str):
                raise InvalidArguments('Shared library soversion is not a string or integer.')
            try:
                int(self.soversion)
            except ValueError:
                raise InvalidArguments('Shared library soversion must be a valid integer')
        elif self.ltversion:
            # library version is defined, get the soversion from that
            self.soversion = self.ltversion.split('.')[0]
        # Visual Studio module-definitions file
        if 'vs_module_defs' in kwargs:
            path = kwargs['vs_module_defs']
            if (os.path.isabs(path)):
                self.vs_module_defs = File.from_absolute_file(path)
            else:
                self.vs_module_defs = File.from_source_file(environment.source_dir, self.subdir, path)

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

    def get_import_filename(self):
        """
        The name of the import library that will be outputted by the compiler

        Returns None if there is no import library required for this platform
        """
        return self.import_filename

    def get_import_filenameslist(self):
        if self.import_filename:
            return [self.vs_import_filename, self.gcc_import_filename]
        return []

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

    def get_aliaslist(self):
        """
        If the versioned library name is libfoo.so.0.100.0, aliases are:
        * libfoo.so.0 (soversion)
        * libfoo.so (unversioned; for linking)
        """
        # Aliases are only useful with .so libraries. Also if the .so library
        # ends with .so (no versioning), we don't need aliases.
        if self.suffix != 'so' or self.filename.endswith('.so'):
            return []
        # Unversioned alias: libfoo.so
        aliases = [self.basic_filename_tpl.format(self)]
        # If ltversion != soversion we create an soversion alias: libfoo.so.X
        if self.ltversion and self.ltversion != self.soversion:
            if not self.soversion:
                # This is done in self.process_kwargs()
                raise AssertionError('BUG: If library version is defined, soversion must have been defined')
            alias_tpl = self.filename_tpl.replace('ltversion', 'soversion')
            aliases.append(alias_tpl.format(self))
        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 __repr__(self):
        repr_str = "<{0} {1}: {2}>"
        return repr_str.format(self.__class__.__name__, self.get_id(), self.command)

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

    def get_target_dependencies(self):
        deps = self.dependencies[:]
        deps += self.extra_depends
        for c in self.sources:
            if hasattr(c, 'held_object'):
                c = c.held_object
            if isinstance(c, BuildTarget) or isinstance(c, CustomTarget) or isinstance(c, GeneratedList):
                deps.append(c)
        return deps

    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) or isinstance(c, File):
                final_cmd.append(c)
            elif isinstance(c, dependencies.ExternalProgram):
                if not c.found():
                    raise InvalidArguments('Tried to use not found external program in a build rule.')
                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 self.install:
                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, dependencies, subdir):
        self.name = name
        self.command = command
        self.args = args
        self.dependencies = dependencies
        self.subdir = subdir

    def __repr__(self):
        repr_str = "<{0} {1}: {2}>"
        return repr_str.format(self.__class__.__name__, self.get_id(), self.command)

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

    def get_basename(self):
        return self.name

    def get_dependencies(self):
        return self.dependencies

    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'
        incdirs = kwargs.get('include_directories', [])

    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 __repr__(self):
        repr_str = "<{0}: {1} -> {2}>"
        src = os.path.join(self.subdir, self.sourcename)
        dst = os.path.join(self.subdir, self.targetname)
        return repr_str.format(self.__class__.__name__, src, dst)

    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 __repr__(self):
        return repr(self.values)

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

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

# A bit poorly named, but this represents plain data files to copy
# during install.
class Data():
    def __init__(self, in_sourcetree, source_subdir, sources, install_dir):
        self.in_sourcetree = in_sourcetree
        self.source_subdir = source_subdir
        self.sources = sources
        self.install_dir = install_dir

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