build/fidl/fidl_library.gni

# Copyright 2018 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/compiled_action.gni")
import("//build/fidl/linting_exceptions.gni")
import("//build/fidl/toolchain.gni")
import("//build/json/validate_json.gni")
import("//build/sdk/sdk_atom.gni")

declare_args() {
  # Whether libraries under //vendor should be linted.
  vendor_linting = false
}

# Generates some representation of a FIDL library that's consumable by Language
# bindings generators.
#
# The parameters for this template are defined in //build/fidl/fidl.gni. The
# relevant parameters in this template are:
#   - api;
#   - name;
#   - sdk_category;
#   - sources.
#
#   should_lint (optional, boolean)
#     If set to false, the linting step is skipped.

template("fidl_library") {
  assert(
      current_toolchain == fidl_toolchain,
      "This template can only be used in the FIDL toolchain $fidl_toolchain.")

  assert(defined(invoker.sources), "A FIDL library requires some sources.")

  library_name = target_name
  if (defined(invoker.name)) {
    library_name = invoker.name
  }

  excluded_checks = []
  if (defined(invoker.excluded_checks)) {
    excluded_checks = invoker.excluded_checks
  }

  experimental_flags = []
  if (defined(invoker.experimental_flags)) {
    experimental_flags = invoker.experimental_flags
  }

  response_file = "$target_gen_dir/$target_name.args"
  fidl_stem = "$target_gen_dir/$target_name.fidl"
  json_representation = "$fidl_stem.json"
  c_stem = string_replace(library_name, ".", "/") + "/c/fidl"
  c_client = "$target_gen_dir/$c_stem.client.c"
  c_header = "$target_gen_dir/$c_stem.h"
  c_server = "$target_gen_dir/$c_stem.server.c"
  coding_tables = "$fidl_stem.tables.c"
  lint_stamp_file = "$target_gen_dir/$target_name.linted"

  main_target_name = target_name
  response_file_target_name = "${target_name}_response_file"
  compilation_target_name = "${target_name}_compile"
  verification_target_name = "${target_name}_verify"
  lint_target_name = "${target_name}_lint"

  # Only artifacts that have various associated FIDL generated targets.
  fidl_deps = []

  # Artifacts other than FIDL, that are also dependencies.
  non_fidl_deps = []

  if (defined(invoker.non_fidl_deps)) {
    non_fidl_deps += invoker.non_fidl_deps
  }

  if (defined(invoker.deps)) {
    fidl_deps += invoker.deps - non_fidl_deps
  }
  if (defined(invoker.public_deps)) {
    fidl_deps += invoker.public_deps
  }

  action(response_file_target_name) {
    visibility = [ ":*" ]

    script = "//build/fidl/gen_response_file.py"

    forward_variables_from(invoker,
                           [
                             "deps",
                             "public_deps",
                             "sources",
                             "testonly",
                           ])

    libraries = "$target_gen_dir/$main_target_name.libraries"

    outputs = [
      response_file,
      libraries,
    ]

    args = [
             "--out-response-file",
             rebase_path(response_file, root_build_dir),
             "--out-libraries",
             rebase_path(libraries, root_build_dir),
             "--json",
             rebase_path(json_representation, root_build_dir),
             "--c-client",
             rebase_path(c_client, root_build_dir),
             "--c-header",
             rebase_path(c_header, root_build_dir),
             "--c-server",
             rebase_path(c_server, root_build_dir),
             "--tables",
             rebase_path(coding_tables, root_build_dir),
             "--name",
             library_name,
             "--sources",
           ] + rebase_path(sources, root_build_dir)

    foreach(flag, experimental_flags) {
      args += [
        "--experimental-flag",
        flag,
      ]
    }

    if (fidl_deps != []) {
      dep_libraries = []

      foreach(dep, fidl_deps) {
        gen_dir = get_label_info(dep, "target_gen_dir")
        name = get_label_info(dep, "name")
        dep_libraries += [ "$gen_dir/$name.libraries" ]
      }

      inputs = dep_libraries

      args += [ "--dep-libraries" ] + rebase_path(dep_libraries, root_build_dir)
    }
  }

  action(lint_target_name) {
    visibility = [ ":*" ]

    script = "//build/fidl/run_and_gen_stamp.sh"

    forward_variables_from(invoker,
                           [
                             "sources",
                             "testonly",
                           ])

    # run_and_gen_stamp.sh runs this tool, and touches lint_stamp_file if successful
    tool_with_no_output = "//zircon/public/tool/fidl-lint"

    # Construct the host toolchain version of the tool.
    host_tool = "${tool_with_no_output}($host_toolchain)"

    # Get the path to the executable.
    if (!defined(tool_output_name)) {
      tool_output_name = get_label_info(host_tool, "name")
    }
    tool_out_dir = get_label_info(host_tool, "root_out_dir")
    host_executable = "$tool_out_dir/$tool_output_name"

    deps = [ host_tool ] + non_fidl_deps

    # Add the executable itself as an input.
    inputs = [ host_executable ]

    outputs = [ lint_stamp_file ]

    should_lint = !defined(invoker.should_lint) || invoker.should_lint

    # unlinted_libraries defined in linting_exceptions.gni
    foreach(library, unlinted_libraries) {
      if (library == library_name) {
        should_lint = false
      }
    }

    full_label = get_label_info(":bogus", "label_no_toolchain")
    in_vendor = string_replace(full_label, "//vendor", "") != full_label
    if (in_vendor && !vendor_linting) {
      # Disable lints for libraries under //vendor.
      # TODO(fxb/36800): remove this exception.
      should_lint = false
    }

    fidl_to_lint = []
    if (should_lint) {
      foreach(source, sources) {
        if (string_replace(source, ".test.", "") == source) {
          # Don't automatically lint test.fidl and test.<various>.fidl files
          fidl_to_lint += [ rebase_path(source, root_build_dir) ]
        }
      }
    }

    args = [ rebase_path(lint_stamp_file, root_build_dir) ]
    if (fidl_to_lint == []) {
      args += [ ":" ]  # NOOP - Nothing to lint, but touch the stamp file
    } else {
      args += [ rebase_path(host_executable, root_build_dir) ]

      if (excluded_checks != []) {
        # Add path to fidl-lint executable, and --must-find-excluded-checks option, so fidl-lint will
        # return an error if any excluded check is no longer required. Excluded checks are only
        # allowed if the target |fidl_to_lint| files still violate those checks. After updating
        # the FIDL files to resolve a lint error, remove the check-id from the list of excluded
        # checks in the fidl() target to prevent the same lint errors from creeping back in, in
        # the future.
        args += [ "--must-find-excluded-checks" ]

        foreach(excluded_check, excluded_checks) {
          args += [
            "-e",
            excluded_check,
          ]
        }
      }

      args += fidl_to_lint
    }
  }

  compiled_action(compilation_target_name) {
    forward_variables_from(invoker, [ "testonly" ])

    visibility = [ ":*" ]

    tool = "//zircon/public/tool/fidlc"

    inputs = [ response_file ]

    outputs = [
      c_client,
      c_header,
      c_server,
      coding_tables,
      json_representation,
    ]

    rebased_response_file = rebase_path(response_file, root_build_dir)

    args = [ "@$rebased_response_file" ]

    deps = [
      ":$lint_target_name",
      ":$response_file_target_name",
    ]
  }

  validate_json(verification_target_name) {
    forward_variables_from(invoker, [ "testonly" ])
    visibility = [ ":*" ]
    data = json_representation
    schema = "//zircon/tools/fidl/schema.json"
    deps = [ ":$compilation_target_name" ]
  }

  group(main_target_name) {
    forward_variables_from(invoker,
                           [
                             "testonly",
                             "visibility",
                             "response_file",
                           ])

    # Metadata to allow us to query all FIDL IR files.
    metadata = {
      fidl_json = [ rebase_path(json_representation, root_build_dir) ]
      generated_sources = fidl_json
    }

    public_deps = [
      ":$compilation_target_name",
      ":$lint_target_name",
      ":$response_file_target_name",
    ]

    deps = [ ":$verification_target_name" ]
  }

  if (defined(invoker.sdk_category) && invoker.sdk_category != "excluded") {
    sdk_category = invoker.sdk_category
    if (sdk_category == "partner" || sdk_category == "public") {
      api_reference = "$library_name.api"
      if (defined(invoker.api)) {
        api_reference = invoker.api
      }
    }

    # Process sources.
    file_base = "fidl/$library_name"
    all_files = []
    sdk_sources = []
    foreach(source, invoker.sources) {
      relative_source = rebase_path(source, ".")
      if (string_replace(relative_source, "..", "bogus") != relative_source) {
        # If the source file is not within the same directory, just use the file
        # name.
        relative_source = get_path_info(source, "file")
      }
      destination = "$file_base/$relative_source"
      sdk_sources += [ destination ]
      all_files += [
        {
          source = rebase_path(source)
          dest = destination
        },
      ]
    }

    # Identify metadata for dependencies.
    sdk_metas = []
    sdk_deps = []
    foreach(dep, fidl_deps) {
      full_label = get_label_info(dep, "label_no_toolchain")
      sdk_dep = "${full_label}_sdk"
      sdk_deps += [ sdk_dep ]
      gen_dir = get_label_info(sdk_dep, "target_gen_dir")
      name = get_label_info(sdk_dep, "name")
      sdk_metas += [ rebase_path("$gen_dir/$name.meta.json") ]
    }

    # Generate the library metadata.
    meta_file = "$target_gen_dir/${target_name}.sdk_meta.json"
    meta_target_name = "${target_name}_meta"

    action(meta_target_name) {
      script = "//build/fidl/gen_sdk_meta.py"

      inputs = sdk_metas

      outputs = [ meta_file ]

      args = [
               "--out",
               rebase_path(meta_file),
               "--name",
               library_name,
               "--root",
               file_base,
               "--specs",
             ] + sdk_metas + [ "--sources" ] + sdk_sources

      deps = sdk_deps
    }

    sdk_atom("${target_name}_sdk") {
      id = "sdk://fidl/$library_name"

      category = sdk_category

      if (defined(api_reference)) {
        api = api_reference

        api_contents = all_files
      }

      meta = {
        source = meta_file
        dest = "$file_base/meta.json"
        schema = "fidl_library"
      }

      files = all_files

      # Metadata to allow us to query all FIDL IR and source files.
      metadata = {
        fidl_json = [ rebase_path(json_representation, root_build_dir) ]
        generated_sources = fidl_json
      }

      non_sdk_deps = [
        ":$compilation_target_name",
        ":$meta_target_name",
      ]

      deps = []
      foreach(dep, fidl_deps) {
        label = get_label_info(dep, "label_no_toolchain")
        deps += [ "${label}_sdk" ]
      }
    }
  }
}