dependencies: refactor python3 into its own file

3 files changed, 146 insertions, 118 deletions

diff --git a/mesonbuild/dependencies/__init__.py b/mesonbuild/dependencies/__init__.py
index b6fdb18..36c3b02 100644
--- a/mesonbuild/dependencies/__init__.py
+++ b/mesonbuild/dependencies/__init__.py
@@ -34,11 +34,12 @@ from .mpi import mpi_factory
 from .scalapack import scalapack_factory
 from .misc import (
     BlocksDependency, OpenMPDependency, cups_factory, curses_factory, gpgme_factory,
-    libgcrypt_factory, libwmf_factory, netcdf_factory, pcap_factory, python3_factory,
+    libgcrypt_factory, libwmf_factory, netcdf_factory, pcap_factory,
     shaderc_factory, threads_factory, ThreadDependency, iconv_factory, intl_factory,
     dl_factory, openssl_factory, libcrypto_factory, libssl_factory,
 )
 from .platform import AppleFrameworks
+from .python import python3_factory
 from .qt import qt4_factory, qt5_factory, qt6_factory
 from .ui import GnuStepDependency, WxDependency, gl_factory, sdl2_factory, vulkan_factory
 
@@ -250,7 +251,6 @@ packages.update({
     'curses': curses_factory,
     'netcdf': netcdf_factory,
     'openmp': OpenMPDependency,
-    'python3': python3_factory,
     'threads': threads_factory,
     'pcap': pcap_factory,
     'cups': cups_factory,
@@ -268,6 +268,9 @@ packages.update({
     # From platform:
     'appleframeworks': AppleFrameworks,
 
+    # from python:
+    'python3': python3_factory,
+
     # From ui:
     'gl': gl_factory,
     'gnustep': GnuStepDependency,
diff --git a/mesonbuild/dependencies/misc.py b/mesonbuild/dependencies/misc.py
index 2913d84..7b075c4 100644
--- a/mesonbuild/dependencies/misc.py
+++ b/mesonbuild/dependencies/misc.py
@@ -15,15 +15,12 @@
 # This file contains the detection logic for miscellaneous external dependencies.
 from __future__ import annotations
 
-from pathlib import Path
 import functools
 import re
-import sysconfig
 import typing as T
 
 from .. import mesonlib
 from .. import mlog
-from ..environment import detect_cpu_family
 from .base import DependencyException, DependencyMethods
 from .base import BuiltinDependency, SystemDependency
 from .cmake import CMakeDependency
@@ -187,108 +184,6 @@ class BlocksDependency(SystemDependency):
             self.is_found = True
 
 
-class Python3DependencySystem(SystemDependency):
-    def __init__(self, name: str, environment: 'Environment', kwargs: T.Dict[str, T.Any]) -> None:
-        super().__init__(name, environment, kwargs)
-
-        if not environment.machines.matches_build_machine(self.for_machine):
-            return
-        if not environment.machines[self.for_machine].is_windows():
-            return
-
-        self.name = 'python3'
-        # We can only be sure that it is Python 3 at this point
-        self.version = '3'
-        self._find_libpy3_windows(environment)
-
-    @staticmethod
-    def get_windows_python_arch() -> T.Optional[str]:
-        pyplat = sysconfig.get_platform()
-        if pyplat == 'mingw':
-            pycc = sysconfig.get_config_var('CC')
-            if pycc.startswith('x86_64'):
-                return '64'
-            elif pycc.startswith(('i686', 'i386')):
-                return '32'
-            else:
-                mlog.log(f'MinGW Python built with unknown CC {pycc!r}, please file a bug')
-                return None
-        elif pyplat == 'win32':
-            return '32'
-        elif pyplat in {'win64', 'win-amd64'}:
-            return '64'
-        mlog.log(f'Unknown Windows Python platform {pyplat!r}')
-        return None
-
-    def get_windows_link_args(self) -> T.Optional[T.List[str]]:
-        pyplat = sysconfig.get_platform()
-        if pyplat.startswith('win'):
-            vernum = sysconfig.get_config_var('py_version_nodot')
-            if self.static:
-                libpath = Path('libs') / f'libpython{vernum}.a'
-            else:
-                comp = self.get_compiler()
-                if comp.id == "gcc":
-                    libpath = Path(f'python{vernum}.dll')
-                else:
-                    libpath = Path('libs') / f'python{vernum}.lib'
-            lib = Path(sysconfig.get_config_var('base')) / libpath
-        elif pyplat == 'mingw':
-            if self.static:
-                libname = sysconfig.get_config_var('LIBRARY')
-            else:
-                libname = sysconfig.get_config_var('LDLIBRARY')
-            lib = Path(sysconfig.get_config_var('LIBDIR')) / libname
-        if not lib.exists():
-            mlog.log('Could not find Python3 library {!r}'.format(str(lib)))
-            return None
-        return [str(lib)]
-
-    def _find_libpy3_windows(self, env: 'Environment') -> None:
-        '''
-        Find python3 libraries on Windows and also verify that the arch matches
-        what we are building for.
-        '''
-        pyarch = self.get_windows_python_arch()
-        if pyarch is None:
-            self.is_found = False
-            return
-        arch = detect_cpu_family(env.coredata.compilers.host)
-        if arch == 'x86':
-            arch = '32'
-        elif arch == 'x86_64':
-            arch = '64'
-        else:
-            # We can't cross-compile Python 3 dependencies on Windows yet
-            mlog.log(f'Unknown architecture {arch!r} for',
-                     mlog.bold(self.name))
-            self.is_found = False
-            return
-        # Pyarch ends in '32' or '64'
-        if arch != pyarch:
-            mlog.log('Need', mlog.bold(self.name), 'for {}-bit, but '
-                     'found {}-bit'.format(arch, pyarch))
-            self.is_found = False
-            return
-        # This can fail if the library is not found
-        largs = self.get_windows_link_args()
-        if largs is None:
-            self.is_found = False
-            return
-        self.link_args = largs
-        # Compile args
-        inc = sysconfig.get_path('include')
-        platinc = sysconfig.get_path('platinclude')
-        self.compile_args = ['-I' + inc]
-        if inc != platinc:
-            self.compile_args.append('-I' + platinc)
-        self.version = sysconfig.get_config_var('py_version')
-        self.is_found = True
-
-    @staticmethod
-    def log_tried() -> str:
-        return 'sysconfig'
-
 class PcapDependencyConfigTool(ConfigToolDependency):
 
     tools = ['pcap-config']
@@ -670,17 +565,6 @@ pcap_factory = DependencyFactory(
     pkgconfig_name='libpcap',
 )
 
-python3_factory = DependencyFactory(
-    'python3',
-    [DependencyMethods.PKGCONFIG, DependencyMethods.SYSTEM, DependencyMethods.EXTRAFRAMEWORK],
-    system_class=Python3DependencySystem,
-    # There is no version number in the macOS version number
-    framework_name='Python',
-    # There is a python in /System/Library/Frameworks, but that's python 2.x,
-    # Python 3 will always be in /Library
-    extra_kwargs={'paths': ['/Library/Frameworks']},
-)
-
 threads_factory = DependencyFactory(
     'threads',
     [DependencyMethods.SYSTEM, DependencyMethods.CMAKE],
diff --git a/mesonbuild/dependencies/python.py b/mesonbuild/dependencies/python.py
new file mode 100644
index 0000000..06dd700
--- /dev/null
+++ b/mesonbuild/dependencies/python.py
@@ -0,0 +1,141 @@
+# Copyright 2022 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 __future__ import annotations
+
+from pathlib import Path
+import sysconfig
+import typing as T
+
+from .. import mlog
+from .base import DependencyMethods, SystemDependency
+from .factory import DependencyFactory
+from ..environment import detect_cpu_family
+
+if T.TYPE_CHECKING:
+    from ..environment import Environment
+
+
+class Python3DependencySystem(SystemDependency):
+    def __init__(self, name: str, environment: 'Environment', kwargs: T.Dict[str, T.Any]) -> None:
+        super().__init__(name, environment, kwargs)
+
+        if not environment.machines.matches_build_machine(self.for_machine):
+            return
+        if not environment.machines[self.for_machine].is_windows():
+            return
+
+        self.name = 'python3'
+        # We can only be sure that it is Python 3 at this point
+        self.version = '3'
+        self._find_libpy3_windows(environment)
+
+    @staticmethod
+    def get_windows_python_arch() -> T.Optional[str]:
+        pyplat = sysconfig.get_platform()
+        if pyplat == 'mingw':
+            pycc = sysconfig.get_config_var('CC')
+            if pycc.startswith('x86_64'):
+                return '64'
+            elif pycc.startswith(('i686', 'i386')):
+                return '32'
+            else:
+                mlog.log(f'MinGW Python built with unknown CC {pycc!r}, please file a bug')
+                return None
+        elif pyplat == 'win32':
+            return '32'
+        elif pyplat in {'win64', 'win-amd64'}:
+            return '64'
+        mlog.log(f'Unknown Windows Python platform {pyplat!r}')
+        return None
+
+    def get_windows_link_args(self) -> T.Optional[T.List[str]]:
+        pyplat = sysconfig.get_platform()
+        if pyplat.startswith('win'):
+            vernum = sysconfig.get_config_var('py_version_nodot')
+            if self.static:
+                libpath = Path('libs') / f'libpython{vernum}.a'
+            else:
+                comp = self.get_compiler()
+                if comp.id == "gcc":
+                    libpath = Path(f'python{vernum}.dll')
+                else:
+                    libpath = Path('libs') / f'python{vernum}.lib'
+            lib = Path(sysconfig.get_config_var('base')) / libpath
+        elif pyplat == 'mingw':
+            if self.static:
+                libname = sysconfig.get_config_var('LIBRARY')
+            else:
+                libname = sysconfig.get_config_var('LDLIBRARY')
+            lib = Path(sysconfig.get_config_var('LIBDIR')) / libname
+        if not lib.exists():
+            mlog.log('Could not find Python3 library {!r}'.format(str(lib)))
+            return None
+        return [str(lib)]
+
+    def _find_libpy3_windows(self, env: 'Environment') -> None:
+        '''
+        Find python3 libraries on Windows and also verify that the arch matches
+        what we are building for.
+        '''
+        pyarch = self.get_windows_python_arch()
+        if pyarch is None:
+            self.is_found = False
+            return
+        arch = detect_cpu_family(env.coredata.compilers.host)
+        if arch == 'x86':
+            arch = '32'
+        elif arch == 'x86_64':
+            arch = '64'
+        else:
+            # We can't cross-compile Python 3 dependencies on Windows yet
+            mlog.log(f'Unknown architecture {arch!r} for',
+                     mlog.bold(self.name))
+            self.is_found = False
+            return
+        # Pyarch ends in '32' or '64'
+        if arch != pyarch:
+            mlog.log('Need', mlog.bold(self.name), 'for {}-bit, but '
+                     'found {}-bit'.format(arch, pyarch))
+            self.is_found = False
+            return
+        # This can fail if the library is not found
+        largs = self.get_windows_link_args()
+        if largs is None:
+            self.is_found = False
+            return
+        self.link_args = largs
+        # Compile args
+        inc = sysconfig.get_path('include')
+        platinc = sysconfig.get_path('platinclude')
+        self.compile_args = ['-I' + inc]
+        if inc != platinc:
+            self.compile_args.append('-I' + platinc)
+        self.version = sysconfig.get_config_var('py_version')
+        self.is_found = True
+
+    @staticmethod
+    def log_tried() -> str:
+        return 'sysconfig'
+
+
+python3_factory = DependencyFactory(
+    'python3',
+    [DependencyMethods.PKGCONFIG, DependencyMethods.SYSTEM, DependencyMethods.EXTRAFRAMEWORK],
+    system_class=Python3DependencySystem,
+    # There is no version number in the macOS version number
+    framework_name='Python',
+    # There is a python in /System/Library/Frameworks, but that's python 2.x,
+    # Python 3 will always be in /Library
+    extra_kwargs={'paths': ['/Library/Frameworks']},
+)