feat: use rust triple instead of python sys module

after this change, cross compilation are supported in theory.

packer/src/sarasacw_omrf_packer/__init__.py

@@ -41,7 +41,7 @@ class App:
         self.__opts = opts
         # build essential instances
         self.__extractor = MetadataExtractor(self.__opts.manifest)
-        self.__ctx = ArtifactContext(self.__extractor)
+        self.__ctx = ArtifactContext(self.__opts, self.__extractor)
 
     def run(self) -> None:
         """Produce the distribution.

packer/src/sarasacw_omrf_packer/artifact.py

@@ -5,12 +5,13 @@ header copies, library copies and generated CMake/pkg-config texts that the
 archiver then materializes.
 """
 
-import sys
 import logging
 from typing import Iterator
 from pathlib import Path
 from dataclasses import dataclass
 from re import Pattern, compile
+from .cli import Cli
+from .utils import Triple
 from .metadata import MetadataExtractor, Metadata
 from .renders.cmake import CMakeProperties, CMakeRender
 from .renders.pkgconfig import PkgConfigProperties, PkgConfigRender
@@ -19,17 +20,24 @@ from .renders.pkgconfig import PkgConfigProperties, PkgConfigRender
 class ArtifactContext:
     """A wrapper of metadata with proper fallback"""
 
+    __opts: Cli
     __extractor: MetadataExtractor
     __metadata: Metadata
 
-    def __init__(self, extractor: MetadataExtractor) -> None:
+    def __init__(self, opts: Cli, extractor: MetadataExtractor) -> None:
         """Wrap an extractor and eagerly fetch its :class:`Metadata`.
 
         :param extractor: The extractor to wrap and read from.
         """
+        self.__opts = opts
         self.__extractor = extractor
         self.__metadata = self.__extractor.get_metadata()
 
+    @property
+    def options(self) -> Cli:
+        """The wrapped :class:`Cli` holding all command line arguments"""
+        return self.__opts
+
     @property
     def extractor(self) -> MetadataExtractor:
         """The wrapped :class:`MetadataExtractor`."""
@@ -112,20 +120,39 @@ def resolve_include_copy(ctx: ArtifactContext) -> Iterator[FileCopyInfo]:
             )
 
 
-def _generate_dll_artifact_name(name: str) -> str:
+_WINDOWS_ENV_IDENTS: tuple[str, ...] = ("windows", "cygwin")
+
+_LINUX_ENV_IDENTS: tuple[str, ...] = (
+    "linux",
+    "android",
+    "freebsd",
+    "openbsd",
+    "netbsd",
+    "haiku",
+    "hurd",
+)
+
+_MACOS_ENV_IDENTS: tuple[str, ...] = ("macos", "ios", "tvos", "visionos")
+
+
+def _is_windows_env(triple: Triple) -> bool:
+    return triple.operating_system in _WINDOWS_ENV_IDENTS
+
+
+def _generate_dll_artifact_name(name: str, triple: Triple) -> str:
     """Return the platform-appropriate dynamic-loadable file name for ``name``."""
-    match sys.platform:
+    match triple.operating_system:
-        case "win32" | "cygwin":
+        case x if x in _WINDOWS_ENV_IDENTS:
             return f"{name}.dll"
-        case "linux" | "android" | "freebsd":
+        case x if x in _LINUX_ENV_IDENTS:
             return f"lib{name}.so"
-        case "darwin" | "ios":
+        case x if x in _MACOS_ENV_IDENTS:
             return f"lib{name}.dylib"
         case _:
             raise RuntimeError("not supported system")
 
 
-def _generate_lib_artifact_name(name: str) -> str:
+def _generate_lib_artifact_name(name: str, _: Triple) -> str:
     """Return the Windows import-library file name for ``name``.
 
     Only meaningful on Windows; returned regardless of platform for use by the
@@ -141,15 +168,21 @@ def resolve_lib_copy(ctx: ArtifactContext) -> Iterator[FileCopyInfo]:
     target_directory = extractor.get_target_directory() / "release"
     target_name = extractor.get_target_name()
 
+    # get triple info
+    target_triple = extractor.get_host_triple()
+    if ctx.options.target is not None:
+        target_triple = ctx.options.target
+
     # copy artifact for redist
-    dll_artifact_filename = _generate_dll_artifact_name(target_name)
+    dll_artifact_filename = _generate_dll_artifact_name(target_name, target_triple)
     yield FileCopyInfo(
         target_directory / dll_artifact_filename,
-        Path("bin" if sys.platform == "win32" else "lib") / dll_artifact_filename,
+        Path("bin" if _is_windows_env(target_triple) else "lib")
+        / dll_artifact_filename,
     )
     # copy artifact for linking only on windows
-    if sys.platform == "win32":
+    if _is_windows_env(target_triple):
-        lib_artifact_filename = _generate_lib_artifact_name(target_name)
+        lib_artifact_filename = _generate_lib_artifact_name(target_name, target_triple)
         yield FileCopyInfo(
             target_directory / lib_artifact_filename,
             Path("lib") / lib_artifact_filename,
@@ -187,6 +220,11 @@ def resolve_cmake_copy(ctx: ArtifactContext) -> Iterator[TextCopyInfo]:
     metadata = ctx.metadata
     target_name = extractor.get_target_name()
 
+    # get triple info
+    target_triple = extractor.get_host_triple()
+    if ctx.options.target is not None:
+        target_triple = ctx.options.target
+
     # compute fallback name
     cmake_fallback_name = _sanitize_name(target_name)
     # get namespace and target name with fallback
@@ -202,8 +240,8 @@ def resolve_cmake_copy(ctx: ArtifactContext) -> Iterator[TextCopyInfo]:
     properties = CMakeProperties(
         cmake_namespace_name,
         cmake_target_name,
-        _generate_dll_artifact_name(target_name),
+        _generate_dll_artifact_name(target_name, target_triple),
-        _generate_lib_artifact_name(target_name),
+        _generate_lib_artifact_name(target_name, target_triple),
         extractor.get_version(),
     )
     render = CMakeRender(properties)

packer/src/sarasacw_omrf_packer/cli.py

@@ -9,6 +9,7 @@ themselves, so the accepted options and their semantics live in one place.
 import argparse
 from dataclasses import dataclass
 from pathlib import Path
+from .utils import Triple
 
 
 @dataclass(frozen=True)
@@ -31,6 +32,10 @@ class Cli:
     """Destination of the zip archive bundling the distribution tree, or
     ``None`` when no archive is requested."""
 
+    target: Triple | None
+    """Target triple to pack for (e.g. ``x86_64-pc-windows-msvc``), or ``None``
+    to pack for the host toolchain."""
+
 
 def parse() -> Cli:
     """Parse command-line arguments into a :class:`Cli` instance.
@@ -77,9 +82,20 @@ def parse() -> Cli:
         help="Path of the zip archive created from the dist-dir contents",
         metavar="ZIP",
     )
+    parser.add_argument(
+        "-t",
+        "--target",
+        dest="target",
+        action="store",
+        type=Triple.parse,
+        required=False,
+        help="Target triple to pack for (e.g. x86_64-pc-windows-msvc). Defaults to the host toolchain.",
+        metavar="TRIPLE",
+    )
     args = parser.parse_args()
     return Cli(
         manifest=args.manifest,
         dist_dir=args.dist_dir,
         dist_zip=args.dist_zip,
+        target=args.target,
     )

packer/src/sarasacw_omrf_packer/metadata.py

@@ -14,10 +14,11 @@ import subprocess
 from dataclasses import dataclass
 from functools import wraps
 from pathlib import Path
+from re import Pattern, compile
 from typing import Any, Callable
 from semver import Version
 from . import utils
-from .utils import dict_chain_get, dict_typed_get, dict_typed_get_required, VERSION
+from .utils import Triple, VERSION, dict_chain_get, dict_typed_get, dict_typed_get_required
 
 
 @dataclass(frozen=True)
@@ -192,6 +193,12 @@ def wrap_metadata_errors[**P, R](func: Callable[P, R]) -> Callable[P, R]:
     return wrapper
 
 
+_SUBPROCESS_TIMEOUT_SEC: int = 10
+"""Timeout in seconds for the ``cargo``/``rustc`` subprocesses launched below."""
+
+_HOST_TRIPLE_PATTERN: Pattern = compile(r"(?m)^host:\s*(\S+)$")
+"""The pattern for match host triple in ``rustc -vV``. The group 1 is the triple result."""
+
 class MetadataExtractor:
     """Access layer over ``cargo metadata`` and the OMRF metadata table.
 
@@ -208,6 +215,8 @@ class MetadataExtractor:
     """The package item in cargo metadata's packages list pointing to user request package"""
     __metadata_target: dict[str, Any]
     """The target item in package item's targets list pointing to the main target"""
+    __host_triple: Triple
+    """The host toolchain triple resolved from ``rustc -vV``"""
 
     def __init__(self, cargo_toml_path: Path) -> None:
         """Run ``cargo metadata`` and locate the package and main target.
@@ -221,6 +230,35 @@ class MetadataExtractor:
         self.__metadata_target = MetadataExtractor.__extract_metadata_target(
             self.__metadata_package, cargo_toml_path
         )
+        self.__host_triple = MetadataExtractor.__extract_host_triple()
+
+    @staticmethod
+    @wrap_metadata_errors
+    def __extract_host_triple() -> Triple:
+        """Query ``rustc -vV`` and parse its ``host:`` line into a :class:`Triple`.
+
+        :raises RuntimeError: if rustc times out, exits with a non-zero status,
+            or its output carries no ``host:`` line.
+        """
+        rustc = os.getenv("OMRF_PACKER_RUSTC", "rustc")
+        proc = subprocess.Popen(
+            [rustc, "-vV"], stdout=subprocess.PIPE, stderr=subprocess.PIPE
+        )
+        try:
+            stdout, stderr = proc.communicate(timeout=_SUBPROCESS_TIMEOUT_SEC)
+        except subprocess.TimeoutExpired:
+            proc.kill()
+            proc.communicate()
+            raise RuntimeError("fail to fetch host triple: timed out")
+        if proc.returncode != 0:
+            raise RuntimeError(
+                "fail to fetch host triple: "
+                + stderr.decode("utf-8", errors="ignore")
+            )
+        m = _HOST_TRIPLE_PATTERN.search(stdout.decode("utf-8", errors="strict"))
+        if m is None:
+            raise RuntimeError("can not find host triple in rustc -vV output")
+        return Triple.parse(m.group(1))
 
     @staticmethod
     @wrap_metadata_errors
@@ -243,7 +281,7 @@ class MetadataExtractor:
         ]
         proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
         try:
-            stdout, stderr = proc.communicate(timeout=10)
+            stdout, stderr = proc.communicate(timeout=_SUBPROCESS_TIMEOUT_SEC)
         except subprocess.TimeoutExpired:
             proc.kill()
             proc.communicate()
@@ -349,3 +387,7 @@ class MetadataExtractor:
     def get_target_name(self) -> str:
         """Return the name of the main library target."""
         return dict_typed_get_required(self.__metadata_target, "name", str)
+
+    def get_host_triple(self) -> Triple:
+        """Return the host toolchain triple resolved at construction time."""
+        return self.__host_triple

packer/src/sarasacw_omrf_packer/utils.py

@@ -4,6 +4,7 @@ Provides version parsing/checking, typed dictionary access helpers, name
 validation and template-directory resolution.
 """
 
+from dataclasses import dataclass
 from pathlib import Path
 from re import Pattern, compile
 from typing import Any, overload
@@ -129,3 +130,45 @@ def is_good_sentence(s: str) -> bool:
     :returns: True if given string don't contain any EOL chars, otherwise false.
     """
     return _EOL_PATTERN.search(s) is None
+
+
+@dataclass(frozen=True)
+class Triple:
+    """A Rust target triple (e.g. ``x86_64-pc-windows-msvc``).
+
+    Decomposes a triple into its ``arch``/``vendor``/``operating_system``/
+    ``env`` components. Use :meth:`parse` to build one from a string and
+    ``str(triple)`` to reconstruct the canonical dashed form.
+    """
+
+    architecture: str
+    """Architecture component (e.g. ``x86_64``, ``aarch64``)."""
+    vendor: str
+    """Vendor component (e.g. ``pc``, ``unknown``, ``apple``)."""
+    operating_system: str
+    """Operating-system component (e.g. ``windows``, ``linux``, ``darwin``)."""
+    environment: str | None
+    """Environment/toolchain component (e.g. ``gnu``, ``msvc``), or ``None`` for
+    3-component triples."""
+
+    def __str__(self) -> str:
+        base = f"{self.architecture}-{self.vendor}-{self.operating_system}"
+        return f"{base}-{self.environment}" if self.environment is not None else base
+
+    @staticmethod
+    def parse(s: str) -> "Triple":
+        """Parse a triple string into a :class:`Triple`.
+
+        :raises ValueError: if the string has fewer than 3 or more than 4
+            dash-separated components.
+        """
+        parts = s.split("-")
+        if len(parts) < 3 or len(parts) > 4:
+            raise ValueError(f"invalid target triple: {s!r}")
+        env = parts[3] if len(parts) == 4 else None
+        return Triple(
+            architecture=parts[0],
+            vendor=parts[1],
+            operating_system=parts[2],
+            environment=env,
+        )