build/host.gni

# Copyright 2017 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.

declare_args() {
  # This is the directory where host tools intended for manual use by
  # developers get installed.  It's something a developer might put
  # into their shell's $PATH.  Host tools that are just needed as part
  # of the build do not get copied here.  This directory is only for
  # things that are generally useful for testing or debugging or
  # whatnot outside of the GN build itself.  These are only installed
  # by an explicit install_host_tools() rule (see //build/host.gni).
  host_tools_dir = "$root_build_dir/tools"
}

# This declares that a host tool (a target built in host_toolchain)
# should be installed in host_tools_dir.  This target can be used in
# any toolchain, and it will forward to host_toolchain.
#
# Parameters
#
#   outputs (required)
#     [files list] Simple file name of each tool, should be the
#     same as the output_name in the executable() or similar rule
#     (which is usually just that target's name).
#
#   deps (recommended)
#     [label list] Should list each target that actually builds each output.
#     It does not need to use explicit toolchain suffixes; the only target
#     using the deps will be instantiated only in host_toolchain.
#
#   testonly (optional)
#   visibility (optional)
#     Standard GN meaning.
#
# Example of usage:
#
#   executable("frob") { ... }
#   install_host_tools("fiddlers") {
#     deps = [ ":frob", "//some/other/dir:twiddle" ]
#     outputs = [ "frob", "twiddle" ]
#   }
template("install_host_tools") {
  assert(defined(invoker.outputs), "install_host_tools() must define outputs")

  copy(target_name) {
    forward_variables_from(invoker,
                           [
                             "deps",
                             "testonly",
                             "visibility",
                           ])
    if (defined(visibility)) {
      visibility += [ ":$target_name" ]
    }
    outputs = [
      "$host_tools_dir/{{source_file_part}}",
    ]
    sources = []
    foreach(output_name, invoker.outputs) {
      sources += [ "$root_out_dir/$output_name" ]
    }
  }
}