build/cpp/sdk_source_set.gni

# Copyright 2018 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.

import("//build/cpp/verify_pragma_once.gni")
import("//build/sdk/sdk_atom.gni")

# A source set that can be exported to an SDK.
#
# An equivalent to the built-in source_set which adds an SDK atom declaration to
# allow the set to be included in an SDK as sources.
#
# Parameters
#
#   category (required)
#     Publication level of the library in SDKs.
#     See //build/sdk/sdk_atom.gni.
#
#   api (optional)
#     Path to the file representing the API of this library.
#     This file is used to ensure modifications to the library's API are
#     explicitly acknowledged. It is mandatory for publication categories of
#     "partner" or "public".
#     Defaults to "<SDK name>.api".
#
#   sdk_name (required)
#     Name of the library in the SDK.
#
#   source_dir (optional)
#     If set, path to the base directory of the sources.
#     This is useful if the sources are generated and therefore not hosted
#     directly under the directory where the GN rules are declared.
#
#   include_base (optional)
#     Path to the root directory for includes.
#     Defaults to "include".
#
#   build_as_static (optional)
#     Whether the sources should be exposed as a static library.
#     This is mostly used in the transition of Zircon libraries to the GN build.
#     Defaults to false.
#
#   non_sdk_deps (optional)
#     List of dependencies that should not be reflected in SDKs.
#     Mostly useful for code generation.
#
#   extra_headers [optional]
#     List of header files that are part of the SDK headers for the library
#     but that must not be exposed as part of the Fuchsia build. This must ONLY
#     be used as a work-around for https://fxbug.dev/60129.
#
template("sdk_source_set") {
  assert(defined(invoker.category), "Must define an SDK category")
  assert(defined(invoker.sdk_name), "Must define an SDK name")

  if (invoker.category == "partner" || invoker.category == "public") {
    api_reference = "${invoker.sdk_name}.api"
    if (defined(invoker.api)) {
      api_reference = invoker.api
    }
  }

  main_target_name = target_name
  sdk_target_name = "${target_name}_sdk"

  target_type = "source_set"
  if (defined(invoker.build_as_static) && invoker.build_as_static) {
    target_type = "static_library"
  }

  target(target_type, main_target_name) {
    forward_variables_from(invoker,
                           "*",
                           [
                             "api",
                             "category",
                             "include_base",
                             "non_sdk_deps",
                             "sdk_name",
                             "source_dir",
                           ])

    if (defined(visibility)) {
      visibility += [ ":$sdk_target_name" ]
    }

    # Ensure this sdk_source_set() is instrumented for coverage when
    # building in the 'coverage-sdk' build variant.
    if (toolchain_variant.name == "coverage-sdk") {
      configs += [ "//build/config/profile:coverage-sdk-source-config" ]
    }
  }

  # Identify dependencies and their metadata files.
  sdk_metas = []
  sdk_deps = []
  all_deps = []
  if (defined(invoker.deps)) {
    all_deps += invoker.deps
  }
  if (defined(invoker.public_deps)) {
    all_deps += invoker.public_deps
  }
  foreach(dep, all_deps) {
    full_label = get_label_info(dep, "label_no_toolchain")
    sdk_dep = "${full_label}_sdk"
    sdk_deps += [ sdk_dep ]

    gen_dir = get_label_info(sdk_dep, "target_gen_dir")
    name = get_label_info(sdk_dep, "name")
    sdk_metas += [ rebase_path("$gen_dir/$name.meta.json") ]
  }

  # Sort headers vs. sources.
  all_headers = []
  all_sources = []
  source_headers_are_public = true
  if (defined(invoker.public)) {
    source_headers_are_public = false
    all_headers += invoker.public
  }
  if (defined(invoker.sources)) {
    foreach(source_file, invoker.sources) {
      extension = get_path_info(source_file, "extension")
      if (extension == "h" && source_headers_are_public) {
        all_headers += [ source_file ]
      } else {
        all_sources += [ source_file ]
      }
    }
    not_needed([ "source_headers_are_public" ])
  } else {
    not_needed([ "source_headers_are_public" ])
  }
  if (defined(invoker.extra_headers)) {
    all_headers += invoker.extra_headers
  }

  # Determine destinations in the SDK for headers and sources.
  file_base = "pkg/${invoker.sdk_name}"
  sdk_metadata_headers = []
  sdk_metadata_sources = []
  sdk_header_files = []
  sdk_files = []
  foreach(header, all_headers) {
    include_base = "include"
    if (defined(invoker.include_base)) {
      include_base = invoker.include_base
    }
    relative_destination = rebase_path(header, include_base)
    destination = "$file_base/include/$relative_destination"
    sdk_metadata_headers += [ destination ]
    sdk_header_files += [
      {
        source = header
        dest = destination
      },
    ]
  }
  sdk_files += sdk_header_files
  foreach(source, all_sources) {
    sdk_metadata_sources += [ "$file_base/$source" ]
    sdk_files += [
      {
        source = source
        dest = "$file_base/$source"
      },
    ]
  }

  verify_pragma_target_name = "${target_name}_sdk_pragma"

  verify_pragma_once(verify_pragma_target_name) {
    headers = all_headers
  }

  metadata_target_name = "${target_name}_sdk_metadata"
  metadata_file = "$target_gen_dir/$target_name.sdk_meta.json"

  action(metadata_target_name) {
    script = "//build/cpp/gen_sdk_sources_meta_file.py"

    inputs = sdk_metas

    outputs = [ metadata_file ]

    args = [
      "--out",
      rebase_path(metadata_file),
      "--name",
      invoker.sdk_name,
      "--root",
      file_base,
      "--include-dir",
      "$file_base/include",
    ]
    args += [ "--deps" ] + sdk_metas
    args += [ "--sources" ] + sdk_metadata_sources
    args += [ "--headers" ] + sdk_metadata_headers

    deps = sdk_deps
  }

  sdk_atom(sdk_target_name) {
    forward_variables_from(invoker,
                           [
                             "source_dir",
                             "testonly",
                           ])

    id = "sdk://pkg/${invoker.sdk_name}"
    category = invoker.category

    if (defined(api_reference)) {
      api = api_reference

      api_contents = sdk_header_files
    }

    meta = {
      source = metadata_file
      dest = "$file_base/meta.json"
      schema = "cc_source_library"
    }

    files = sdk_files

    deps = sdk_deps

    non_sdk_deps = [
      ":$main_target_name",
      ":$metadata_target_name",
      ":$verify_pragma_target_name",
    ]

    # Explicitly add non-public dependencies, in case some of the source files
    # are generated.
    if (defined(invoker.non_sdk_deps)) {
      non_sdk_deps += invoker.non_sdk_deps
    }

    metadata = {
      # Used by the //sdk:sdk_source_set_list build API module.
      sdk_source_set_sources = rebase_path(all_sources + all_headers, "//")
    }
  }
}

set_defaults("sdk_source_set") {
  configs = default_common_binary_configs
}