build/dart/label_to_package_name.py

#!/usr/bin/env python3.8
# Copyright 2016 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 sys

# TODO(abarth): Base these paths on the sdk_dirs variable in gn.
_SDK_DIRS = [
    "garnet/public/",
    "topaz/public/",
]


# Strip the sdk dirs from the given label, if necessary.
def _remove_sdk_dir(label):
    for prefix in _SDK_DIRS:
        if label.startswith(prefix):
            return label[len(prefix):]
    return label


# For target //foo/bar:blah, the package name will be foo.bar._blah.
# For default targets //foo/bar:bar, the package name will be foo.bar.
def convert(label):
    if not label.startswith("//"):
        sys.stderr.write("expected label to start with //, got %s\n" % label)
        return 1
    base = _remove_sdk_dir(label[2:])
    separator_index = base.rfind(":")
    if separator_index < 0:
        sys.stderr.write("could not find target name in label %s\n" % label)
        return 1
    path = base[:separator_index].split("/")
    name = base[separator_index + 1:]
    if path[-1] == name:
        return ".".join(path)
    else:
        return "%s._%s" % (".".join(path), name)


def main():
    print(convert(sys.argv[1]))


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