build/python/python_c_extension_shared_lib.gni

# Copyright 2023 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Defines a python C extension shared library.
#
# This is not directly importable into a Python `.pyz`.
# This builds a .so file that can be loaded into python if its parent directory
# is included in the PYTHONPATH environment variable.
template("python_c_extension_shared_lib") {
  assert(defined(invoker.sources), "sources is required")
  assert(is_host, "python C extensions can only be built on host")

  shared_library(target_name) {
    output_prefix_override = true
    forward_variables_from(invoker,
                           [
                             "assert_no_deps",
                             "public_configs",
                             "testonly",
                             "sources",
                             "deps",
                             "visibility",
                           ])
    if (defined(invoker.configs)) {
      configs += invoker.configs
    }
    configs += [ "//build/config/python:python_c_extension_shared_lib_config" ]

    if (!defined(invoker.deps)) {
      deps = []
    }
    deps += [ "//build/config/python:generate_python_api_symbols" ]

    if (host_os == "mac") {
      configs += [ "//build/config/mac:symbol_dynamic_lookup_undefined" ]

      # For mac the usual naming convention is to have .dylib as the extension.
      # However, Python only expects C extensions to have a .so extension.
      output_extension = "so"
    }
  }
}