# Copyright 2019 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/distribution_manifest.gni")
import("//src/sys/build/fuchsia_package.gni")

# Produce a package that collects all binaries entries produced by packages
# declared in deps, into a new package.
#
# There are two ways of contributing to a shell_commands package:
# 1. Preferred: using the `shell_command()` template below.
# 2. Legacy: using the `package()` template by specifying `shell = true`.
#
# The generated package doesn't include any actual binaries, but rather
# "trampolines" that launch these binaries from other packages.
# This allows putting a shell_commands package in base, such that it cannot be
# updated at runtime, while updating the packages that include the actual
# binaries.
#
# Paramters
#
#   package_name (optional)
#     Default: target_name
#
#   deps (optional)
#   testonly (optional)
#   visibility (optional)
#     Usual GN meanings.
template("shell_commands") {
  # Collect all shell binaries.
  shell_binary_entries_target = "${target_name}_shell_binary_entries"
  shell_binary_entries = "$target_out_dir/$shell_binary_entries_target"
  generated_file(shell_binary_entries_target) {
    forward_variables_from(invoker,
                           [
                             "deps",
                             "testonly",
                           ])
    visibility = [ ":*" ]

    # This contract is known to package.gni.
    data_keys = [
      "shell_binary_entries",
      "shell_binary_entries_files",
    ]
    walk_keys = [ "shell_binary_barrier" ]
    outputs = [ shell_binary_entries ]
    output_conversion = "json"
    metadata = {
      # Don't pick up resources from deps
      distribution_entries_barrier = []
    }
  }

  # Expose the distribution manifest to the shell commands package.
  distribution_entries_target = "${target_name}_distribution_entries_file"
  distribution_entries_file(distribution_entries_target) {
    forward_variables_from(invoker, [ "testonly" ])
    visibility = [ ":*" ]
    deps = [ ":$shell_binary_entries_target" ]
    file = shell_binary_entries
  }

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

# Wrap binaries as shell commands.
#
# Any binaries produced by `deps` will be available in the shell, and can be
# launched for instance with `fx shell`.
#
# Binaries will be available in the shell by their intrinsic names.
# For instance, if you defined:
#
#   executable("foo") { ... }
#
# Then adding ":foo" to your deps will result in the binary "foo" being
# available in the shell.
# To rename binaries, change their intrinsic name. For instance:
#
#   executable("foo") {
#     output_name = "bar"
#   }
#
# Parameters
#
#   package_name (required)
#     The name of a package that the binary is included in.
#
#   deps (required)
#     One or more targets that package files into `bin/`.
#
#   testonly
#   visibility
template("shell_command") {
  assert(defined(invoker.package_name), "Must specify package_name")
  assert(defined(invoker.deps), "Must specify deps")

  # Collect all distribution entries from deps.
  distribution_manifest_target = "${target_name}_distribution_manifest"
  distribution_manifest = "$target_out_dir/$distribution_manifest_target"
  distribution_manifest(distribution_manifest_target) {
    forward_variables_from(invoker,
                           [
                             "deps",
                             "testonly",
                           ])
    visibility = [ ":*" ]
    outputs = [ distribution_manifest ]
  }

  # Generate shebang files for each `bin/` entry,
  # then create distribution entries for the generated shebang files.
  output = "$target_out_dir/${target_name}_resolve_files"
  depfile = "$target_out_dir/$target_name.d"
  action(target_name) {
    forward_variables_from(invoker,
                           [
                             "deps",
                             "testonly",
                             "visibility",
                           ])
    script = "//build/images/shell_commands.py"
    inputs = [ distribution_manifest ]
    outputs = [ output ]
    args = [
      "--package-name",
      invoker.package_name,
      "--input-distribution-manifest",
      rebase_path(distribution_manifest, root_build_dir),
      "--output-directory",
      rebase_path(target_gen_dir, root_build_dir),
      "--output-distribution-manifest",
      rebase_path(output, root_build_dir),
      "--depfile",
      rebase_path(depfile, root_build_dir),
    ]
    depfile = depfile
    if (!defined(invoker.deps)) {
      deps = []
    }
    deps += [ ":$distribution_manifest_target" ]
    metadata = {
      shell_binary_entries_files = [
        {
          file = rebase_path(output, root_build_dir)
          label = get_label_info(":$target_name", "label_with_toolchain")
        },
      ]
    }
  }
}