lib/build_target_lib.py

# Copyright 2019 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Build target class and related functionality."""

import os
import re
from typing import Optional


class Error(Exception):
    """Base module error class."""


class BuildTarget:
    """Class to handle the build target information."""

    def __init__(
        self,
        name: Optional[str],
        profile: Optional[str] = None,
        build_root: Optional[str] = None,
    ):
        """Build Target init.

        Args:
            name: The full name of the target.
            profile: The profile name.
            build_root: The path to the buildroot.
        """
        self._name = name or None
        self.profile = profile

        if build_root:
            self.root = os.path.normpath(build_root)
        else:
            self.root = get_default_sysroot_path(self.name)

    def __eq__(self, other):
        if self.__class__ is other.__class__:
            return (
                self.name == other.name
                and self.profile == other.profile
                and self.root == other.root
            )

        return NotImplemented

    def __hash__(self):
        return hash(self.name)

    def __str__(self):
        return self.name

    @property
    def name(self):
        return self._name

    def full_path(self, *args):
        """Turn a sysroot-relative path into an absolute path."""
        return os.path.join(self.root, *[part.lstrip(os.sep) for part in args])

    def get_command(self, base_command: str) -> str:
        """Get the build target's variant of the given base command.

        We create wrappers for many scripts that handle the build target's
        arguments. Build the target-specific variant for such a command.
        e.g. emerge -> emerge-eve.

        TODO: Add optional validation the command exists.

        Args:
            base_command: The wrapped command.

        Returns:
            The build target's command wrapper.
        """
        if self.is_host():
            return base_command

        return "%s-%s" % (base_command, self.name)

    def is_host(self) -> bool:
        """Check if the build target refers to the host."""
        return not self.name


def get_default_sysroot_path(build_target_name=None):
    """Get the default sysroot location or / if |build_target_name| is None."""
    if build_target_name is None:
        return "/"
    return os.path.join("/build", build_target_name)


def get_sdk_sysroot_path() -> str:
    """Get the SDK's sysroot path.

    Convenience/clarification wrapper for get_default_sysroot_path for use when
    explicitly fetching the SDK's sysroot path.
    """
    return get_default_sysroot_path()


def is_valid_name(build_target_name):
    """Validate |build_target_name| is a valid name."""
    return bool(re.match(r"^[a-zA-Z0-9-_]+$", build_target_name))