devshell/rustfmt

#!/usr/bin/env python
# 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.

### runs rustfmt on a Rust target

import argparse
import os
import platform
import subprocess
import sys

import lib.rust
from lib.rust import ROOT_PATH, CONFIG_PATH

sys.path += [os.path.join(ROOT_PATH, "third_party", "pytoml")]
import pytoml as toml

def main():
    parser = argparse.ArgumentParser("Format a rust target")
    parser.add_argument("gn_target",
                        type=lib.rust.GnTarget,
                        help="GN target to format. \
                              Use '.[:target]' to discover the cargo target \
                              for the current directory or use the \
                              absolute path to the target \
                              (relative to $FUCHSIA_DIR). \
                              For example: //garnet/bin/foo/bar:baz.")
    parser.add_argument("-v", "--verbose",
                        action='store_true',
                        help="Show verbose output")
    parser.add_argument("-s", "--print-sources",
                        action='store_true',
                        help="Only print sources; do not format")

    args = parser.parse_args()

    out_dir = lib.rust.find_out_dir()

    if args.print_sources and not os.path.exists(args.gn_target.manifest_path(out_dir)):
        return 0

    with open(args.gn_target.manifest_path(out_dir), "r") as fin:
        cargo_toml = toml.load(fin)

    main_file = None
    if 'bin' in cargo_toml:
        bins = cargo_toml['bin']
        if len(bins) != 1:
            print("Expected a single bin target for {gn_target}, found {n}".format(
                    gn_target = args.gn_target,
                    n = len(bins)))
            return 1
        main_file = bins[0]['path']
    elif 'lib' in cargo_toml:
        main_file = cargo_toml['lib']['path']

    if args.print_sources:
        if main_file:
            print(main_file)
        return 0

    if not main_file or not os.path.exists(main_file):
        print("No source root (typically lib.rs or main.rs) found for this gn target")
        return 1

    host_platform = "%s-%s" % (
        platform.system().lower().replace("darwin", "mac"),
        {
            "x86_64": "x64",
            "aarch64": "arm64",
        }[platform.machine()],
    )
    buildtools_dir = os.path.join(ROOT_PATH, "buildtools", host_platform)
    rustfmt = os.path.join(buildtools_dir, "rust", "bin", "rustfmt")

    call_args = [
        rustfmt,
        main_file,
    ]

    if args.verbose:
        call_args.append("-v")

    return subprocess.call(call_args)

if __name__ == '__main__':
    sys.exit(main())