third_party/closure_compiler/compile_js.gni

# Copyright 2017 The Chromium 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("//third_party/closure_compiler/closure_args.gni")

script_path = "//third_party/closure_compiler"
compiler_path = "$script_path/compiler/compiler.jar"

# Defines a target that creates an ordering for .js files to be used by
# js_binary to compile.
#
# Variables:
#   sources:
#     List of Javascript files to include in the library
#
#   deps:
#     List of js_library targets to depend on
#
# Example:
#   js_library("apple_tree") {
#     sources = ["tree_main.js"]
#     deps = [
#       ":branch",
#       ":trunk",
#       ":root",
#     ]
#   }

template("js_library") {
  assert(defined(invoker.sources) || defined(invoker.deps),
         "Need sources or deps in $target_name for js_library")
  action(target_name) {
    script = "$script_path/js_library.py"
    forward_variables_from(invoker,
                           [
                             "sources",
                             "deps",
                           ])
    output_file = "$target_gen_dir/$target_name.js_library"
    outputs = [
      output_file,
    ]
    args = [ "--output" ] + [ rebase_path(output_file, root_build_dir) ]
    if (defined(sources)) {
      args += [ "--sources" ] + rebase_path(sources, root_build_dir)
    }
    if (defined(deps)) {
      args += [ "--deps" ]
      foreach(dep, deps) {
        # Get the output path for each dep
        dep_gen_dir = get_label_info(dep, "target_gen_dir")
        dep_name = get_label_info(dep, "name")
        dep_output_path = "$dep_gen_dir/$dep_name.js_library"
        args += [ rebase_path(dep_output_path, root_build_dir) ]
      }
    }
  }
}

# Defines a target that compiles javascript files using the Closure compiler.
# This will produce a minified javascript output file. Additional checks and
# optimizations can be configured using the closure_flags attribute.
#
# Variables:
#   sources:
#     List of .js files to compile
#
#   deps:
#     List of js_library rules to depend on
#
#   outputs:
#     A file to write the compiled .js to.
#     Only takes in a single file, but must be placed in a list
#
#   bootstrap_file:
#      A .js files to include before all others
#
#   config_files:
#     A list of .js files to include after the bootstrap_file but before all
#     others
#
#   closure_flags:
#     A list of custom flags to pass to the Closure compiler.  Do not include
#     the leading dashes
#
#   externs_list:
#     A list of .js files to pass to the compiler as externs
#
# Example:
#   js_binary("tree") {
#     sources = ["tree_main.js"]
#     deps = [":apple_tree"]
#     outputs = [ "$target_gen_dir/tree.js" ]
#     bootstrap_file = "bootstrap.js"
#     config_files = [
#       "config1.js",
#       "config2.js",
#     ]
#     closure_flags = ["jscomp_error=undefinedVars"]
#     externs_list = [ "externs.js" ]
#   }

template("js_binary") {
  assert(defined(invoker.sources) || defined(invoker.deps),
         "Need sources or deps in $target_name for js_binary")
  assert(defined(invoker.outputs), "Need outputs in $target_name for js_binary")

  action(target_name) {
    script = "$script_path/js_binary.py"
    forward_variables_from(invoker,
                           [
                             "sources",
                             "deps",
                             "outputs",
                             "bootstrap_file",
                             "config_files",
                             "closure_flags",
                             "externs_list",
                           ])
    args = [
      "--compiler",
      rebase_path(compiler_path, root_build_dir),
    ]
    args += [ "--output" ] + rebase_path(outputs, root_build_dir)
    if (defined(sources)) {
      args += [ "--sources" ] + rebase_path(sources, root_build_dir)
    } else {
      sources = []
    }
    if (defined(deps)) {
      args += [ "--deps" ]
      foreach(dep, deps) {
        # Get the output path for each dep
        dep_gen_dir = get_label_info(dep, "target_gen_dir")
        dep_name = get_label_info(dep, "name")
        dep_output_path = "$dep_gen_dir/$dep_name.js_library"
        args += [ rebase_path(dep_output_path, root_build_dir) ]
      }
    }
    if (defined(bootstrap_file)) {
      args += [
        "--bootstrap",
        rebase_path(bootstrap_file, root_build_dir),
      ]
      sources += [ bootstrap_file ]
    }
    if (defined(config_files)) {
      args += [ "--config" ] + rebase_path(config_files, root_build_dir)
      sources += config_files
    }

    # |minifying_closure_args| from
    # //third_party/closure_compiler/closure_args.gni
    args += [ "--flags" ] + minifying_closure_args
    if (defined(closure_flags)) {
      args += closure_flags
    }
    if (defined(externs_list)) {
      args += [ "--externs" ]
      args += rebase_path(externs_list, root_build_dir)
      sources += externs_list
    }
  }
}