# 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("fuchsia_component.gni")
import("fuchsia_package.gni")

# Defines a package that contains a single component.
# See: https://fuchsia.dev/fuchsia-src/development/components/build
#
# Developers often define a package that contains a single component.
# This template fuses together fuchsia_package() and fuchsia_component() as a
# convenience.
#
# Packages are units of distribution. It is beneficial to define multiple
# components in the same package if you need to guarantee that several
# components are always co-present, or if you'd like to be able to update
# several components at once (by updating a single package).
# This pattern is also commonly used to create hermetic integration tests.
# For instance an integration test between two components where one is a client
# of a service implemented in another component would include both the client
# and server components.
# However for the sake of simplicity, if you're developing a package with just
# a single component then this template will save you some boilerplate.
#
# Example:
# ```
# executable("rot13_encoder_decoder") {
#   sources = [ "rot13_encoder_decoder.cc" ]
# }
#
# fuchsia_package_with_single_component("rot13") {
#   manifest = "meta/rot13.cmx"
#   deps = [ ":rot13_encoder_decoder" ]
# }
# ```
#
# Parameters
#
#   package_name (optional)
#     The name of the package.
#     Type: string
#     Default: target_name
#
#   component_name (optional)
#     The name of the component.
#     Type: string
#     Default: target_name
#
#   manifest (required)
#     The component manifest.
#     Type: path
#
#   deps
#   testonly
#   visibility
template("fuchsia_package_with_single_component") {
  assert(
      defined(invoker.manifest),
      "A `manifest` argument was missing when calling fuchsia_package_with_single_component($target_name)")

  package_name = target_name
  if (defined(invoker.package_name)) {
    package_name = invoker.package_name
  }
  component_name = target_name
  if (defined(invoker.component_name)) {
    component_name = invoker.component_name
  }

  component_target = "${target_name}_component"
  fuchsia_component(component_target) {
    forward_variables_from(invoker,
                           [
                             "deps",
                             "manifest",
                             "testonly",
                           ])
    component_name = component_name
    visibility = [ ":*" ]
  }

  fuchsia_package(target_name) {
    forward_variables_from(invoker,
                           [
                             "testonly",
                             "visibility",
                           ])
    package_name = package_name
    deps = [ ":$component_target" ]
  }
}