Source code for craft_parts.plugins.cargo_use_plugin

# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
#
# Copyright 2025 Canonical Ltd.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License version 3 as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""The cargo-use plugin.

This plugin copy the content of the Rust repository to the local crates registry.
"""

import shutil
import sys
from typing import Literal

from typing_extensions import override

from craft_parts import errors

from .base import Plugin
from .properties import PluginProperties

if sys.version_info >= (3, 11):
    import tomllib
else:
    # Python 3.10 compatibility
    import tomli as tomllib  # type: ignore[import-not-found]

CARGO_TOML_TEMPLATE = """\
[source.craft-parts]
directory = "{registry_dir}"

[source.apt]
directory = "/usr/share/cargo/registry"

[source.crates-io]
replace-with = "craft-parts"
"""




class CargoUsePluginProperties(PluginProperties, frozen=True):
    """The part properties used by the cargo-use plugin."""

    plugin: Literal["cargo-use"] = "cargo-use"
    source: str  # pyright: ignore[reportGeneralTypeIssues]





class CargoUsePlugin(Plugin):
    """Copy the content of the Rust repository and ."""

    properties_class = CargoUsePluginProperties



    @override
    def get_build_snaps(self) -> set[str]:
        """Return a set of required snaps to install in the build environment."""
        return set()




    @override
    def get_pull_commands(self) -> list[str]:
        """Return a list commands to retrieve dependencies during the pull step."""
        return []




    @override
    def get_build_packages(self) -> set[str]:
        """Return a set of required packages to install in the build environment."""
        return set()




    @override
    def get_build_environment(self) -> dict[str, str]:
        """Return a dictionary with the environment to use in the build step."""
        return {}




    @override
    def get_build_commands(self) -> list[str]:
        """Return a list of commands to run during the build step."""
        registry_dir = (
            self._part_info.project_info.dirs.backstage_dir / "cargo-registry"
        )

        part_registry_target = (
            self._part_info.part_export_dir
            / "cargo-registry"
            / self._get_cargo_registry_dir_name()
        )
        if part_registry_target.exists():
            # as we don't track files we have to delete previous content
            # to avoid conflicts on rebuild
            shutil.rmtree(part_registry_target)
        part_registry_target.mkdir(parents=True)

        cargo_config = self._part_info.work_dir / "cargo/config.toml"
        if not cargo_config.exists():
            cargo_config.parent.mkdir(exist_ok=True, parents=True)
            cargo_config.write_text(
                CARGO_TOML_TEMPLATE.format(registry_dir=registry_dir)
            )

        checksum_file = part_registry_target / ".cargo-checksum.json"

        if not checksum_file.exists():
            # create checksum_file
            checksum_file.write_text('{"files":{}}')

        return [f'cp --archive --link --no-dereference . "{part_registry_target}"']


    def _get_cargo_registry_dir_name(self) -> str:
        """Create a name for the cargo-registry directory based on Cargo.toml."""
        cargo_toml = self._part_info.part_src_subdir / "Cargo.toml"
        if not cargo_toml.exists():
            raise errors.PartsError(
                "Cannot use 'cargo-use' plugin on non-Rust project."
            )
        try:
            parsed_toml = tomllib.loads(cargo_toml.read_text())
        except tomllib.TOMLDecodeError as err:
            raise errors.PartsError(
                f"Cannot parse Cargo.toml for {self._part_info.part_name!r}"
            ) from err
        else:
            package_dict = parsed_toml.get("package")
            if not package_dict:
                raise errors.PartsError("Package section is missing in Cargo.toml file")
            package_name = package_dict.get("name", self._part_info.part_name)

            # according to the docs this field is optional since 1.7.5 and defaults to 0.0.0
            # it is required for publishing crates, so it should be available for most packages
            # https://doc.rust-lang.org/cargo/reference/manifest.html#the-version-field
            package_version = package_dict.get("version", "0.0.0")
            return f"{package_name}-{package_version}"