meson: Skeleton for python3-netplan build

meson.build

@@ -40,6 +40,7 @@ subdir('include')
 subdir('src')
 subdir('dbus')
 subdir('netplan')
+subdir('python-cffi')
 subdir('examples')
 subdir('doc')
 

python-cffi/.gitignore

@@ -0,0 +1,4 @@
+_libnetplan*.c
+_libnetplan*.o
+_libnetplan*.so
+

python-cffi/__init__.py

@@ -0,0 +1,18 @@
+# Copyright (C) 2023 Canonical, Ltd.
+# Author: Lukas Märdian <[email protected]>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 3.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Re-export submodules
+from .parser import *
+from .state import *

python-cffi/_build_cffi.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+
+# Copyright (C) 2023 Canonical, Ltd.
+# Author: Lukas Märdian <[email protected]>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 3.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+
+from cffi import FFI
+ffibuilder = FFI()
+
+# cdef() expects a single string declaring the C types, functions and
+# globals needed to use the shared object. It must be in valid C syntax.
+ffibuilder.cdef("""
+    typedef int gint;
+    typedef gint gboolean;
+    typedef struct GError NetplanError;
+    typedef struct netplan_parser NetplanParser;
+    typedef struct netplan_state NetplanState;
+    typedef enum {
+        NETPLAN_BACKEND_NONE,
+        NETPLAN_BACKEND_NETWORKD,
+        NETPLAN_BACKEND_NM,
+        NETPLAN_BACKEND_OVS,
+        NETPLAN_BACKEND_MAX_,
+    } NetplanBackend;
+
+    NetplanParser* netplan_parser_new();
+    void netplan_parser_clear(NetplanParser **npp);
+    gboolean netplan_parser_load_yaml(NetplanParser* npp, const char* filename, NetplanError** error);
+    gboolean netplan_parser_load_yaml_from_fd(NetplanParser* npp, int input_fd, NetplanError** error);
+    //gboolean netplan_parser_load_yaml_hierarchy(NetplanParser* npp, const char* rootdir, GError** error);
+    gboolean netplan_parser_load_keyfile(NetplanParser* npp, const char* filename, NetplanError** error);
+    gboolean netplan_parser_load_nullable_fields(NetplanParser* npp, int input_fd, NetplanError** error);
+    //gboolean netplan_parser_load_nullable_overrides(NetplanParser* npp, int input_fd, const char* constraint, GError** error);
+
+    NetplanState* netplan_state_new();
+    void netplan_state_reset(NetplanState* np_state);
+    void netplan_state_clear(NetplanState** np_state);
+    NetplanBackend netplan_state_get_backend(const NetplanState* np_state);
+""")
+
+# set_source() gives the name of the python extension module to
+# produce, and some C source code as a string.  This C code needs
+# to make the declarated functions, types and globals available,
+# so it is often just the "#include".
+ffibuilder.set_source_pkgconfig("_libnetplan0", ['glib-2.0'],
+"""
+    // the C header of the library
+    #include "netplan.h"
+    #include "parse.h"
+    #include "parse-nm.h"
+""",
+    include_dirs=[os.getenv('CFFI_INC')],
+    library_dirs=[os.getenv('CFFI_LIB')],
+    libraries=['netplan', 'glib-2.0'])   # library name, for the linker
+
+if __name__ == "__main__":
+    ffibuilder.compile(verbose=False)

python-cffi/meson.build

@@ -0,0 +1,26 @@
+pymod = import('python')
+python = pymod.find_installation(
+    'python3',
+    modules: ['cffi']
+)
+
+#https://mesonbuild.com/FAQ.html#but-i-really-want-to-use-wildcards
+out = run_command(
+    'sh', '-c', 'python3 _build_cffi.py && find -name _libnetplan*.so',
+    env: [
+        'CFFI_INC=' + join_paths(meson.project_source_root(), 'include'),
+        'CFFI_LIB=' + join_paths(meson.current_build_dir(), 'src'),
+    ],
+    check: true,
+)
+cffi_so = out.stdout().strip().split('\n')
+
+bindings_sources = '''
+  __init__.py
+  parser.py
+  state.py
+'''.split()
+
+bindings = python.install_sources(
+    [bindings_sources, cffi_so],
+    subdir: 'netplan')

python-cffi/parser.py

@@ -0,0 +1,24 @@
+# Copyright (C) 2023 Canonical, Ltd.
+# Author: Lukas Märdian <[email protected]>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 3.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from ._libnetplan0 import ffi, lib
+
+class Parser():
+    def __init__(self):
+        self._ptr = lib.netplan_parser_new()
+
+    def __del__(self):
+        ref = ffi.new('NetplanParser **', self._ptr)
+        lib.netplan_parser_clear(ref)

python-cffi/state.py

@@ -0,0 +1,21 @@
+# Copyright (C) 2023 Canonical, Ltd.
+# Author: Lukas Märdian <[email protected]>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 3.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from ._libnetplan0 import ffi, lib
+
+class State():
+    def __init__(self):
+        state = lib.netplan_state_new()
+        print(lib.netplan_state_get_backend(state))