# 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("//build/fuzzing/generated_v1_manifest.gni")
import("//src/sys/build/fuchsia_component.gni")

# Defines a Fuchsia component for a fuzzer.
# See: https://fuchsia.dev/fuchsia-src/development/components/build
#
# This template extends `fuchsia_component` by automatically generating a fuzzer manifest to act as
# the component manifest. A fuzzer is a binary that generates and tests inputs in a (possibly open-
# ended) loop, looking for evidence of defects (e.g. crashes, memory corruptions, hangs, etc.).
#
# This template is NOT typically used directly. Instead, use templates like `fuzzer` from
# //build/fuzzing/fuzzer.gni
#
# Parameters:
#
#   fuzzer (required)
#     [string] The name of the fuzzer.
#
#   label (required)
#     [label] The GN label of the associated fuzzer.
#
#   deps (required)
#     [list of labels] Same meaning as for `fuchsia_component`, but required. This typically
#       includes the fuzzer binary. It may also include the fuzzer corpus and dictionary, when
#       present.
#
#   options (optional)
#     [list of strings] Key-value pairs representing libFuzzer options, e.g. "foo=bar". See
#       See https://llvm.org/docs/LibFuzzer.html#options.
#
template("fuzzer_component") {
  assert(defined(invoker.fuzzer),
         "missing 'fuzzer' for fuzzer_component($target_name)")
  assert(defined(invoker.label),
         "missing 'label' for fuzzer_component($target_name)")
  assert(defined(invoker.deps),
         "missing 'deps' for fuzzer_component($target_name)")

  manifest_target = "${target_name}_generated_v1_manifest"
  manifest_output = "$target_gen_dir/${invoker.fuzzer}.cmx"
  generated_v1_manifest(manifest_target) {
    manifest = manifest_output
    binary = "bin/" + invoker.fuzzer
    if (defined(invoker.options)) {
      args = []
      foreach(option, invoker.options) {
        args += [ "-$option" ]
      }
    }
    services = [
      "fuchsia.logger.LogSink",
      "fuchsia.process.Launcher",
    ]
    features = [
      "isolated-persistent-storage",
      "isolated-temp",
    ]
    metadata = {
      fuzz_spec = [
        {
          label = invoker.label
          fuzzer = invoker.fuzzer
          manifest = get_path_info(manifest_output, "file")
        },
      ]
    }
  }

  fuchsia_component(target_name) {
    forward_variables_from(invoker, [ "visibility" ])
    component_name = invoker.fuzzer
    testonly = true
    deps = invoker.deps + [ ":$manifest_target" ]
    manifest = manifest_output
  }
}