# Copyright 2021 The Fuchsia Authors
#
# Use of this source code is governed by a MIT-style
# license that can be found in the LICENSE file or at
# https://opensource.org/licenses/MIT

import("//build/zbi/zbi_input.gni")

# Defines a kernel package, a directory namespace within a STORAGE_KERNEL ZBI
# item in the BOOTFS format, for a dependent zbi() target. This namespace -
# given by $target_name - is comprised of the resource() targets - or those
# that contribute resource()-like metadata - within the dependency graph.
#
# Parameters
#
#   * deps
#     - Required: Dependencies to reach all `resource()` targets and the like.
#       Note that this should *not* reach another kernel_package() target (or,
#       equivalently, a zbi_input() with $prefix set) as the $target_name
#       prefix would *not* compound the prefix on a target in this $deps list.
#       Instead, distribution_manifest() targets with $prefix set can be used
#       to "layer" the kernel-package prefix on a prefixed collection inside.
#     - Type: list(label)
#
#   * data_deps
#     - Optional: The usual GN meaning, though in this case no resource()
#     targets in its graph will contribute to the dependent ZBI.
#     - Type: list(label)
#
#   * prefix
#     - Optional: The directory prefix for files reached by `deps`.
#       This should be left to the default for actual kernel packages,
#       and used only for special cases that go outside package selection.
#     - Type: string
#     - Default: "$target_name"
#
#   * metadata, testonly, visibility
#     - Optional: The usual GN meanings.
#
template("kernel_package") {
  zbi_input(target_name) {
    forward_variables_from(invoker,
                           [
                             "data_deps",
                             "deps",
                             "prefix",
                             "testonly",
                             "visibility",
                           ])
    args = [
      # Package entries are relatively small and should compress quickly
      # enough.
      "--compressed=max",
      "--files-type=kernel",
    ]

    # This prefix will apply in the zbi command line to the zbi_input_args
    # elements that come directly from this zbi_input() target, i.e. via the
    # implicit distribution_manifest() collection done here.  But it won't
    # apply to the zbi_input_args metadata found in deps/data_deps, which
    # appear *before* this target's zbi_input_args in the zbi() collection.
    if (!defined(prefix)) {
      prefix = target_name
    }
  }
}