build/components/fuchsia_package.gni

# Copyright 2020 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/dist/fini_manifest.gni")
import("//build/dist/verify_manifest_elf_binaries.gni")
import("//build/images/args.gni")
import("//build/packages/package_metadata.gni")
import("//src/sys/pkg/bin/pm/pm.gni")
import("//tools/cmc/build/cmc.gni")

# Defines a Fuchsia package.
# See: https://fuchsia.dev/fuchsia-src/development/components/build
#
# Fuchsia packages are a collection of any number of files (or resources), each
# with a unique path that is relative to the package's root.
# Package targets collect resources via their dependencies. These dependencies
# are typically fuchsia_component() targets, which provide their component
# manifest and other files that the component needs (such as an executable).
#
# Packages can be defined as a collection of pairs each representing a file in
# the package. Each pair consists of the path in the package that is assigned
# to the file, and a path relative to the build system's output directory where
# the contents of the file will be sourced from.
# This mapping is generated at build time, and is known as the package
# manifest.
#
# To view the package manifest, For instance assume you have defined
# a package at `path/to/project:my_package` and built it:
# ```
# $ fx build path/to/project:my_package
# ```
# You can then find the path to the generated manifest:
# ```
# $ fx gn outputs out/default path/to/project:my_package_manifest
# ```
#
# The package name is defined by the target name.
# Some rules apply to package names.
# See: https://fuchsia.dev/fuchsia-src/concepts/packages/package_url#package-name
#
# It's recommended for a package to depend on one or more `fuchsia_component()`
# targets. Typically no other dependencies are required.
#
# Example:
# ```
# fuchsia_package("my-package") {
#   deps = [
#     ":first_component",
#     ":second_component",
#   ]
# }
# ```
#
# Parameters
#
#   package_name (optional)
#     The name of the package.
#     Type: string
#     Default: target_name
#
#   disable_elf_binaries_checks (optional)
#     Set to true to disable ELF binaries verification checks. Useful
#     if your package includes non-Fuchsia ELF binaries, or if some
#     of them are unstripped.
#     Type: boolean
#     Default: false
#
#    system_image_package_allowed_in_extra_deps (optional)
#     Used internally to implement fuchsia_system_package(), do not use!
#     If defined, this is a fuchsia_system_package(), and the argument value
#     determines whether it is allowed in extra dependency trees beside
#     the one from //build/input:system_image.
#     Type: boolean
#
#   deps
#   testonly
#   visibility
template("fuchsia_package") {
  if (current_toolchain == target_toolchain) {
    package_name = target_name
    if (defined(invoker.package_name)) {
      package_name = invoker.package_name
    }

    # Generate the "meta/package" file
    meta_package_target = "${target_name}_meta_package"
    generate_meta_package(meta_package_target) {
      forward_variables_from(invoker, [ "testonly" ])
      visibility = [ ":*" ]
      package_name = package_name
    }

    # Generate package manifest
    package_manifest_target = "${target_name}_manifest"
    package_manifest_file = "$target_out_dir/${target_name}_manifest"
    fini_manifest(package_manifest_target) {
      forward_variables_from(invoker,
                             [
                               "deps",
                               "testonly",
                             ])
      if (!defined(deps)) {
        deps = []
      }
      deps += [ ":$meta_package_target" ]
      visibility = [ ":*" ]
      outputs = [ package_manifest_file ]
    }

    # Verify ELF binaries
    verify_elf = !(defined(invoker.disable_elf_binaries_checks) &&
                   invoker.disable_elf_binaries_checks)
    if (verify_elf) {
      package_manifest_verify_target = "${target_name}.verify"
      verify_manifest_elf_binaries(package_manifest_verify_target) {
        forward_variables_from(invoker, [ "testonly" ])
        manifest = package_manifest_file
        deps = [ ":$package_manifest_target" ]
      }
    }

    _is_system_package = false
    if (defined(invoker.system_image_package_allowed_in_extra_deps)) {
      _is_system_package = true
      _is_system_package_allowed_in_extra_deps =
          invoker.system_image_package_allowed_in_extra_deps
    }

    # Build package
    pm_build(target_name) {
      forward_variables_from(invoker,
                             [
                               "all_outputs_fresh",
                               "deps",
                               "testonly",
                               "visibility",
                             ])
      manifest = ":$package_manifest_target"
      metadata = {
        if (defined(invoker.metadata)) {
          forward_variables_from(invoker.metadata, "*")
        }
        if (!bootfs_only && !_is_system_package) {
          # Installing a Fuchsia package into another one should not also install
          # its content to the root install location, which is why this metadata key
          # is set to an empty list. However, there are two exceptions to this:
          #
          #  - fuchsia_system_package() instances whose content must end up
          #    into either the system image (handled by system_image_package_info below)
          #    or the boot filesystem (handled through distribution_manifest().
          #
          #  - When 'bootfs_only' is set to true, which corresponds to the "bringup"
          #    configuration which requires subtle adjustments in the build graph.
          #
          distribution_entries_barrier = []
        }

        # Used by system_image_fuchsia_packages_list() to allow embedding
        # the content of this package into the system image, if necessary.
        #
        # The schema is the following:
        #
        #   label: GN label of this target (used for debugging only).
        #   fini_manifest: path to FINI manifest listing this package's content.
        #   system_image_packaged_allowed_in_extra_deps: (optional)
        #     If defined, this is a fuchsia_system_package() instance, and its
        #     value determines whether it is allowed in extra dependency trees
        #     (see fuchsia_system_package() description for details). If undefined,
        #     this is a regular fuchsia_package().
        #
        system_image_package_info = [
          {
            label = get_label_info(":$target_name", "label_with_toolchain")
            fini_manifest = rebase_path(package_manifest_file, root_build_dir)
            if (_is_system_package) {
              system_image_package_allowed_in_extra_deps =
                  _is_system_package_allowed_in_extra_deps
            }
          },
        ]
        system_image_package_barrier = []
      }
      if (!defined(deps)) {
        deps = []
      }
      if (verify_elf) {
        deps += [ ":$package_manifest_verify_target" ]
      }
    }
  } else {
    # Fuchsia packages should only be built with target_toolchain. However, it
    # is possible for package targets to be expanded in other toolchains (host,
    # variant, etc.). In these cases, make fuchsia_package expand to nothing.
    group(target_name) {
    }

    # Suppress unused variable warnings.
    not_needed(invoker, "*")
  }
}