Implement linux

Signed-off-by: Cristian Le <git@lecris.dev>

Author: LecrisUT

src/scikit_build_core/repair_wheel/linux.py

@@ -4,10 +4,14 @@
 
 from __future__ import annotations
 
+import os.path
+from pathlib import Path
 from typing import TYPE_CHECKING
 
-import auditwheel  # noqa: F401
+from auditwheel.elfutils import elf_read_rpaths
+from auditwheel.patcher import Patchelf
 
+from .._logging import logger
 from . import WheelRepairer
 
 if TYPE_CHECKING:
@@ -23,6 +27,64 @@ class LinuxWheelRepairer(WheelRepairer):
 
     _platform = "Linux"
 
+    def patch_linux_library_rpath(self, lib: Path, rpaths: list[str]) -> None:
+        """Patch the rpaths of a specific library."""
+        # Flatten the current rpaths
+        curr_rpaths = {
+            path for dt_rpaths in elf_read_rpaths(lib).values() for path in dt_rpaths
+        }
+        final_rpaths = set()
+        # Patch pre-existing rpaths
+        for rpath_str in curr_rpaths:
+            # If the rpath is already relative keep it
+            if rpath_str.startswith("$ORIGIN"):
+                final_rpaths.add(rpath_str)
+                continue
+            # Otherwise check if we need to patch it
+            rpath_path = Path(rpath_str)
+            try:
+                rpath_path.relative_to(self.install_dir)
+            except ValueError:
+                # If it does not point to wheel install path, just keep it
+                final_rpaths.add(rpath_str)
+                continue
+            # Otherwise change the RPATH to point use $ORIGIN
+            new_rpath = os.path.relpath(rpath_str, lib.parent)
+            new_rpath = f"$ORIGIN/{new_rpath}"
+            final_rpaths.add(new_rpath)
+        # Merge with all the rpaths we were given
+        final_rpaths = final_rpaths.union(rpaths)
+        patcher = Patchelf()
+        patcher.set_rpath(lib, ":".join(final_rpaths))
+
     def patch_target(self, target: Target) -> None:
-        # TODO: Implement patching
-        pass
+        # Get the target install paths where the $ORIGIN is calculated from
+        target_install_paths = self.get_wheel_install_paths(target)
+        if not target_install_paths:
+            logger.debug(
+                "Skip patching {target} because all install paths are outside the wheel.",
+                target=target.name,
+            )
+            return
+        if len(set(target.artifacts)) != 1:
+            logger.warning(
+                "Unexpected multiple artifacts for target {target}: {artifacts}",
+                target=target.name,
+                artifacts=[item.path for item in target.artifacts],
+            )
+            return
+        artifact = target.artifacts[0]
+        for install_path in target_install_paths:
+            target_path = self.install_dir / install_path
+            dependency_rpaths = []
+            for dep_target in self.get_library_dependencies(target):
+                dep_install_paths = self.get_wheel_install_paths(dep_target)
+                assert len(dep_install_paths) == 1
+                dep_path = self.install_dir / next(iter(dep_install_paths))
+                rpath = os.path.relpath(dep_path, target_path)
+                rpath = f"$ORIGIN/{rpath}"
+                dependency_rpaths.append(rpath)
+            self.patch_linux_library_rpath(
+                lib=target_path / artifact.path,
+                rpaths=dependency_rpaths,
+            )