build(meson): more robust python build

.gitignore

@@ -86,3 +86,4 @@ output/
 .idea/
 
 scratch/
+subprojects/.wraplock

meson.build

@@ -18,11 +18,32 @@
 #   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 #
 # *********************************************************************** #
-project('libconstants', 'cpp', version: 'v1.1.5', default_options: ['cpp_std=c++23'], meson_version: '>=1.5.0')
+project('libconstants', 'cpp', version: 'v1.1.6', default_options: ['cpp_std=c++23'], meson_version: '>=1.5.0')
 
 # Add default visibility for all C++ targets
 add_project_arguments('-fvisibility=default', language: 'cpp')
 
+if get_option('build_python')
+    local_py_install = import('python').find_installation('python3', pure: false)
+    fourdst_pkg = local_py_install.get_install_dir() / 'fourdst'
+
+    constants_libdir             = fourdst_pkg / 'lib'
+    constants_header_install_dir = fourdst_pkg / 'include' / 'fourdst' / 'constants'
+
+    vendor_lib_dir             = fourdst_pkg / 'lib' / 'vendor'
+    vendor_header_dir          = fourdst_pkg / 'include' / 'fourdst' / 'vendor'
+
+    message('Installing libconfig in python mode. Install locations are...')
+else
+    constants_libdir             = get_option('libdir')
+    constants_header_install_dir = get_option('includedir') / 'fourdst' / 'constants'
+
+    message('Installing libconfig in non python (normal) mode. Install locations are...')
+endif
+message('    Libraries: ' + constants_libdir)
+message('    Headers:   ' + constants_header_install_dir)
+
+
 cpp = meson.get_compiler('cpp')
 
 subdir('assets/static')
@@ -45,7 +66,6 @@ if get_option('pkg_config')
         description: 'Physical Constants for SERiF and related projects',
         version: meson.project_version(),
         libraries: [libconst, '-Wl,-rpath,${libdir}'],
-        subdirs: ['fourdst'],
         filebase: 'fourdst_constants',
         install_dir: join_paths(get_option('libdir'), 'pkgconfig')
     )

meson_options.txt

@@ -1,5 +1,4 @@
 option('pkg_config', type: 'boolean', value: true, description: 'generate pkg-config file for libconstants (fourdst_constants.pc)')
 option('build_tests', type: 'boolean', value: true, description: 'control if tests are built or not')
 option('build_examples', type: 'boolean', value: true, description: 'control if examples is built or not')
-option('lib_install_dir', type: 'string', value: '', description: 'Override install dir for the shared library (used by the fourdst umbrella to place libs inside the Python package in wheel builds). Empty = default libdir.')
+option('build_python', type: 'boolean', value: false, description: 'Build in python mode. Note that this does not generate a wheel; rather, this is the appropriate option to turn on when packaging this component inside of a wheel.')
-option('header_install_dir', type: 'string', value: '', description: 'Override the header install root (used by the fourdst umbrella to place headers inside the Python package in wheel builds). Empty = default includedir.')

src/constants/meson.build

@@ -5,14 +5,13 @@ const_sources = files(
 
 
 # Define the libconst library so it can be linked against by other parts of the build system
-fourdst_component_libdir = get_option('lib_install_dir') != '' ? get_option('lib_install_dir') : get_option('libdir')
 libconst = library('const',
     const_sources, 
     include_directories: include_directories('include'),
     cpp_args: ['-fvisibility=default'],
     dependencies: [const_data_dep],
     install : true,
-    install_dir: fourdst_component_libdir)
+    install_dir: constants_libdir)
 
 const_dep = declare_dependency(
     include_directories: include_directories('include'),
@@ -24,8 +23,4 @@ const_headers = files(
   'include/fourdst/constants/const.h'
 )
 
-
-constants_header_install_dir = get_option('header_install_dir') != '' \
-    ? get_option('header_install_dir') / 'fourdst' / 'constants' \
-    : get_option('includedir') / 'fourdst' / 'constants'
 install_headers(const_headers, install_dir: constants_header_install_dir)