# 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("$zx/public/gn/build_api_module.gni")
import("$zx/public/gn/config/standard.gni")
import("$zx/public/gn/copied_files_dir.gni")
import("$zx/public/gn/prebuilt.gni")
import("$zx/public/gn/test/zbi_test.gni")
import("$zx/public/gn/toolchain/c_utils.gni")
import("$zx/public/gn/toolchain/environment_redirect.gni")
import("$zx/public/gn/zbi.gni")

declare_args() {
  # Defines the `//:default` target: what `ninja` with no arguments does.
  # TODO(BLD-353): This must be set by the controlling Fuchsia GN build.
  default_deps = false
}

assert(default_deps != false,
       "TODO(BLD-353): Zircon build must be driven by Fuchsia build")

###
### Build API modules.
###

# This is the top-level build API module that just lists all the others.
# Each element of the list is the simple name of the API module; the
# module's contents are found at "$root_build_dir/$target_name.json".
#
# TODO(BLD-353): Note this does not include build_api_module() uses meant
# just for legacy build integration.  We don't consider those to be actual
# build API modules; using build_api_module() is just a convenience for
# creating them.  Importantly, they are not part of the API contract with
# consumers of the overall build.  They're purely implementation details of
# the temporary Frankenbuild arrangement.
#
# Type: list(string)
build_api_module("api") {
  testonly = true
  data_keys = [ "build_api_modules" ]
  deps = [
    ":binaries",
    ":buildargs",
    ":generated_sources",
    ":images",
    ":packages",
    ":tests",
    ":tool_paths",
  ]
}

# This just regurgitates the build arguments specified to `gn gen`.  This is
# the exact JSON representation of the settings in "$root_build_dir/args.gn".
# It does not include build arguments left to their default values.  So to
# reproduce the settings of this build, one could put in `args.gn`:
# ```
#   forward_variables_from(read_file("buildargs.json", "json"), "*")
# ```
# Type: scope
build_api_module("buildargs") {
  # The file does not exist at all if `gn gen` is run with no `--args`.  But
  # read_file() can't handle an optional file and there's no direct way to test
  # for file existence from GN.
  contents = exec_script("/bin/sh",
                         [
                           "-c",
                           "test ! -e args.gn || cat args.gn",
                         ],
                         "scope")
}

# This describes all the binaries linked by the build.
#
# This enumerates each linked binary (executable, shared library, or
# loadable/"plug-in" module).  This includes host tools, kernels, boot
# loaders, drivers, as well as normal executables.  It does not yet include
# any non-native binary formats.  This is meant to reach the entire
# dependency graph of all binaries that the build would ever produce.  Not
# every binary described is necessary actually produced by any given Ninja
# run.  Either the $debug or the $dist file for any individual binary can
# be passed to Ninja as a specific target argument to ensure it's built and
# up to date before making use of that binary.  Like all build_api_module()
# targets, the top-level "binaries" target serves as a Ninja target to
# request that every binary described be built.
#
# Type: list(scope)
#
#   cpu
#     Required: CPU architecture the binary is for, e.g. "arm64" or "x64".
#     Type: string
#
#   os
#     Required: OS the binary is for, e.g. "fuchsia", "linux", or "mac".
#     Type: string
#
#   environment
#     Required: The ${toolchain.environment} name of what specific
#     execution this was built for, e.g. "user", "host", "guest".  The
#     tuple of ($cpu, $os, $environment) should indicate what hardware and
#     software environment this binary is compatible with.
#     Type: string
#
#   label
#     Required: The GN label of the binary target.
#     Type: label_with_toolchain
#
#   type
#     Required: The type of binary.
#     Type: "executable" or "shared_library" or "loadable_module"
#
#   debug
#     Required: Path to where the unstripped or separate debug file is
#     found, relative to $root_build_dir.  If $dist is omitted, this
#     is also the file that is used at runtime.
#     Type: path relative to $root_build_dir
#
#   dist
#     Optional: Path to where the stripped binary for deployment/execution is
#     found, relative to $root_build_dir.  This binary may be required for
#     some debugging tasks if $debug is a separate debug file rather than
#     an unstripped file.  It should exactly match the binary that will be
#     seen on devices or run directly on hosts.
#     Type: path relative to $root_build_dir
#
#   elf_build_id
#     Optional: Path to a file containing the lowercase ASCII hexadecimal
#     representation of the ELF build ID in this binary.  This is omitted
#     for OS environments that don't use ELF.  For an ELF binary that
#     doesn't have a build ID note, this key will be present but point to
#     an empty file.
#     Type: path relative to $root_build_dir
#
build_api_module("binaries") {
  testonly = true
  deps = [ ":everything" ] + default_deps
  data_keys = [ "binaries" ]
}

# This describes all the generated source files in the build.
#
# The intent is that telling Ninja to build all these individual files
# will be the minimal work sufficient for source code analysis of all
# the files described in the compilation database to be viable.
#
# Type: list(path relative to $root_build_dir)
#
build_api_module("generated_sources") {
  testonly = true
  deps = [
    ":everything",
  ]
  data_keys = [ "generated_sources" ]
}

# This describes all the "image" files the build can produce.
#
# Consumers of the build should look here for the images to be built.
# The $cpu, $name, and $type fields identify the purpose of each image.
# Consumers are expected to ignore extra images they have no use for or
# whose fields they don't understand.
#
# The $path field indicates where the file is found in the build
# directory.  The presence of an image in the list means that the build
# *can* produce it, not that the build *will* produce it.  Hence,
# consumers should use $path as an explicit argument to Ninja to ensure
# that each needed image gets built.
#
# Type: list(scope)
#
#   cpu
#     Required: CPU architecture the image is for, e.g. "arm64" or "x64".
#     Type: string
#
#   name
#     Required: The primary way that this image is known to consumers.
#     Note that the name need not be unique within the images list.
#     The tuple of ($name, $type, $cpu) should be unique.
#     Type: string
#
#   label
#     Required: The GN label of the image target.
#     Type: label_with_toolchain
#
#   path
#     Required: Path to where the file is found, relative to $root_build_dir.
#     This is also the argument to Ninja that ensures this image will be built.
#     Type: path relative to $root_build_dir
#
#   testonly
#     Optional: This image includes test code/data not meant for production.
#     Type: bool
#     Default: false
#
#   tags
#     Optional: Tags associated with the image.  Certain tags may indicate
#     to the build API consumer what should be done with the image.
#     Type: list(string)
#
#   type
#     Required: Type of file, e.g. "zbi".  This often corresponds to the
#     extension used on the image file name, but not always.  For many
#     miscellaneous formats, this is just "bin" and the consumer is
#     expected to understand what the particular format is for particular
#     $name, $cpu combinations.  Other types include:
#      * "zbi": the ZBI (<zircon/boot/image.h>) format
#      * "efi": an EFI executable that an EFI boot loader can load
#      * "kernel": some other format loaded by a boot loader or emulator
#      * "blk": contents to be written to a storage device or partition
#     Type: string
#
build_api_module("images") {
  testonly = true
  data_keys = [ "images" ]
  deps = [
    ":everything",
  ]
}

# Packages defined in the build.
#
# Type: list(scope)
#
#   * name
#     - Required: Name of the package.
#     - Type: string
#
#   * label
#     - Required: GN label of the package() target.
#     - Type: label_with_toolchain
#
#   * cpu, os
#     - Required: $current_cpu and $current_os values, respectively, for
#       which this package is intended.
#     - Type: string
#
#   * manifest
#     - Required: Manifest file of the package's sandbox filesystem contents.
#     - Type: path relative to $root_build_dir
#
#   * tags
#     - Optional: List of tags to associate with the package.
#     - Type: list(string)
#
#   * testonly
#     - Optional: True if this package should never be in a production build.
#     - Type: bool
#     - Default: false
#
build_api_module("packages") {
  testonly = true
  data_keys = [ "packages" ]
  deps = [
    ":everything",
  ]
}

# Tests in the build.
#
#  Below, the "testing root" refers to $root_build_dir on host, and the full
#  filesystem path from the root on device.
#
# Type: list(scope)
#
#   * name
#     - Required: Name of test.
#     - Type: string
#
#   * label
#     - Required: GN label associated with the test
#     - Type: label_with_toolchain
#
#   * path
#     - Required: Path to the test's executable.
#     - Type: path relative to the testing root.
#
#   * cpu, os
#     - Required: $current_cpu and $current_os values, respectively, for
#       which this test is intended.
#     - Type: string
#
#   * disabled
#     - Optional: a string indicating a reason for the test being disabled.
#
build_api_module("tests") {
  testonly = true
  data_keys = [ "test_specs" ]
  deps = default_deps
}

# Tools provided by the build or as prebuilts, to be used outside the build.
#
# Type: list(scope)
#
#   * name
#     - Required: Name of a host tool.
#     - Type: string
#
#   * label
#     - Required: GN label associated with the tool.
#     - Type: label_with_toolchain
#
#   * path
#     - Required: Path to the tool's executable for the build host.
#     - Type: path relative to $root_build_dir
#
#   * cpu, os
#     - Required: $current_cpu and $current_os values, respectively, for
#       which this tool is intended.
#     - Type: string
#
build_api_module("tool_paths") {
  testonly = true
  deps = [
    ":tool_paths.metadata",
    "$zx/public/gn/toolchain:llvm-tools",
    "tools",
  ]
  data_keys = [ "tool_paths" ]
}

group("tool_paths.metadata") {
  visibility = [ ":tool_paths" ]
  _eponymous_3p_tools = [
    "gn",
    "ninja",
  ]
  metadata = {
    tool_paths = []
    foreach(tool, _eponymous_3p_tools) {
      tool_paths += [
        {
          cpu = host_cpu
          label = get_label_info(":$target_name", "label_with_toolchain")
          name = tool
          os = host_os
          path = rebase_path(
                  "$prebuilt_dir/third_party/$tool/$host_platform/$tool",
                  root_build_dir)
        },
      ]
    }
  }
}

###
### Top-level targets.
###

# This collects all the top-level targets that should contribute to the
# "everything" target, which is the root of build_api_module() metadata walks.
_everything_deps = [ "tools:all-hosts" ]

# Just building this constitutes a useful test that the build system and
# compiler configurations work as intended.  It may also entail building a
# lot of stuff that is not actually useful to build and/or cannot be tested
# easily (or at all).
group("build-tests") {
  testonly = true
  deps = [
    "$zx/public/gn/toolchain:noop-test",
  ]
}
_everything_deps += [ ":build-tests" ]

# This is used in the top-level build_api_module() deps to reach "everything".
# Note that "all" is a magical target name to Ninja, hence this name instead.
group("everything") {
  testonly = true
  deps = _everything_deps
}

# This is the default target that Ninja builds when given no target arguments.
group("default") {
  testonly = true
  deps = default_deps
}

###
### TODO(BLD-353): Temporary hacks for integrating with the legacy Fuchsia
### GN build.
###

if (current_toolchain == default_toolchain) {
  build_api_module("legacy_dirs") {
    testonly = true
    data_keys = [ "legacy_dirs" ]
    walk_keys = [ "legacy_barrier" ]
    deps = []
    foreach(cpu, standard_fuchsia_cpus) {
      deps += [ ":legacy-$cpu" ]
    }
  }

  foreach(cpu, standard_fuchsia_cpus) {
    group("legacy-$cpu") {
      testonly = true
      deps = [
        ":legacy-aux-$cpu",
        ":legacy-image-$cpu",
        ":legacy-tests-$cpu",
        ":legacy_targets-$cpu",
      ]
    }

    build_api_module("legacy_targets-$cpu") {
      testonly = true
      data_keys = [ "legacy_targets" ]
      walk_keys = [ "legacy_barrier" ]
      deps = [
        ":all-ulib-$cpu",
        "$zx/system/banjo",
        "$zx/system/fidl",
        "tools",
      ]
    }

    build_api_module("legacy_sysroot-$cpu") {
      testonly = true
      data_keys = [ "legacy_sysroot" ]
      walk_keys = [ "legacy_barrier" ]
      deps = [
        ":all-ulib-$cpu",
      ]
    }

    build_api_module("legacy_fuzzers-$cpu") {
      testonly = true
      data_keys = [ "fuzzer" ]
      deps = [
        ":legacy-tests-$cpu",
      ]
    }
  }
}

foreach(cpu, standard_fuchsia_cpus) {
  if (current_toolchain == default_toolchain) {
    zbi("legacy-image-$cpu") {
      output_dir = root_build_dir
      testonly = true
      cpu = cpu
      deps = [
        ":legacy-deps-$cpu",
      ]
      metadata = {
        # legacy-$cpu depends on this to get all these deps built.
        # But they shouldn't contribute metadata to the build_api_module().
        legacy_barrier = []
      }
    }

    zbi_input("legacy-tests-$cpu") {
      output_dir = root_build_dir
      testonly = true
      cpu = cpu
      deps = [
        ":legacy-tests-deps-$cpu",
      ]
    }

    # The legacy Fuchsia GN build needs to consume a manifest of libraries
    # built for ASan (and all the libraries themselves).  When the main
    # build is ASan, it needs to find the non-ASan libraries here too.
    manifest_file("legacy-aux-$cpu") {
      testonly = true
      deps = [
        ":all-ulib-$cpu",
        ":driver-deps-$cpu",
        ":instrumented-ulib-$cpu",

        # Include the tests so their libraries are in the aux manifest
        # when individual binaries are drawn from the tests manifest.
        ":legacy-tests-deps-$cpu",
      ]
      metadata = {
        # This prevents build_api_module("legacy-$cpu") from visiting the
        # ASan incarnations of all the libraries.  The legacy build wants
        # only the manifest of ASan shared libraries.  It wants the targets
        # themselves only from the primary build.
        legacy_barrier = []
      }
    }
  }

  environment_redirect("legacy-deps-$cpu") {
    visibility = [ ":*" ]
    testonly = true
    environment_label = "$zx/public/gn/toolchain:user"
    cpu = cpu
    deps = [
      "$zx/bootloader",
      "$zx/kernel",
      "$zx/system/core",
      "$zx/system/dev",
      "$zx/system/uapp",
      "$zx/third_party/uapp",
    ]
    metadata = {
      legacy_barrier = []
    }
  }

  environment_redirect("legacy-tests-deps-$cpu") {
    visibility = [ ":*" ]
    testonly = true
    environment_label = "$zx/public/gn/toolchain:user"
    cpu = cpu
    direct = true
    deps = [
      "$zx/system/utest",
    ]
  }

  environment_redirect("all-ulib-$cpu") {
    testonly = true
    cpu = cpu
    environment_label = "$zx/public/gn/toolchain:user"
    shlib = true
    exclude_variant_tags = [ "instrumented" ]
    deps = [
      "$zx/system/ulib",
    ]
  }

  environment_redirect("driver-deps-$cpu") {
    testonly = true
    cpu = cpu
    environment_label = "$zx/public/gn/toolchain:user"
    exclude_variant_tags = [ "instrumented" ]
    deps = [
      "$zx/system/core/devmgr:driver_deps",
      "$zx/system/core/devmgr:driver_deps.asan",
    ]
  }

  environment_redirect("instrumented-ulib-$cpu") {
    testonly = true
    cpu = cpu
    environment_label = "$zx/public/gn/toolchain:user"
    deps = [
      ":instrumented-ulib-redirect",
    ]
  }
}

if (toolchain.environment == "user") {
  instrumented_variants = []
  foreach(selector, toolchain.variant_selectors) {
    if (selector.tags + [ "instrumented" ] - [ "instrumented" ] !=
        selector.tags) {
      instrumented_variants += [ selector.variant ]
      instrumented_variants -= [ selector.variant ]
      instrumented_variants += [ selector.variant ]
    }
  }
  group("instrumented-ulib-redirect") {
    testonly = true
    visibility = [ ":*" ]
    deps = []
    foreach(variant, instrumented_variants) {
      deps += [ ":instrumented-ulib-redirect.$variant" ]
    }
  }
  foreach(variant, instrumented_variants) {
    environment_redirect("instrumented-ulib-redirect.$variant") {
      testonly = true
      visibility = [ ":instrumented-ulib-redirect" ]
      variant = variant
      deps = [
        "$zx/system/ulib",
      ]
      foreach(dep, toolchain.implicit_deps) {
        if (dep == "$dep") {
          deps += [ dep ]
        } else {
          deps += dep.add
        }
      }
    }
  }
}

build_api_module("legacy_images") {
  testonly = true
  data_keys = [ "images" ]
  deps = [
    "tools",
  ]
  foreach(cpu, standard_fuchsia_cpus) {
    deps += [ ":legacy-$cpu" ]
  }
}

# TODO(BLD-353): This is just for the legacy build and is not really a
# proper build API module.  In the unified build, this string will just be
# directly embedded inside test metadata.
build_api_module("zbi_test_success_string") {
  contents = zbi_test_success_string
}

# This describes pre-generated FIDL bindings that are required by the build.
#
# TODO(BLD-441): This will go away when fidlgen is built in this build.
# See $zx/public/gn/fidl/llcpp.gni, where the metadata is generated.
#
# Type: list(scope)
#
#   name
#     Required: The FIDL library name as it appears in FIDL source (with dots).
#     Type: string
#
#   label
#     Required: The label of the fidl_library() target.
#     Type: label_no_toolchain
#
#   json
#     Required: Path to the fidlc --json output.
#     Type: path relative to $root_build_dir
#
#   target_gen_dir
#     Required: The place in the source tree where generated files go.
#     Type: path relative to $root_build_dir
#
#   args
#     Required: Argument list for `fidlgen` if run in $root_build_dir.
#     Type: list(string)
#
build_api_module("fidl_gen") {
  testonly = true
  data_keys = [ "fidl_gen" ]
  deps = default_deps
}