up

hardlink.go

@@ -0,0 +1,70 @@
+package main
+
+import (
+	"fmt"
+	"io/fs"
+	"log"
+	"os"
+	"path/filepath"
+)
+
+// processHardlinks creates hardlinks in destBase/destSubdir mirroring the
+// structure found at contentPath (either a single file or a directory tree).
+func processHardlinks(cfg *Config, contentPath, destSubdir string) error {
+	info, err := os.Stat(contentPath)
+	if err != nil {
+		return fmt.Errorf("stat %q: %w", contentPath, err)
+	}
+
+	destDir := filepath.Join(cfg.DestBase, destSubdir)
+
+	if info.IsDir() {
+		return hardlinkDir(contentPath, destDir)
+	}
+	return hardlinkFile(contentPath, filepath.Join(destDir, filepath.Base(contentPath)))
+}
+
+// hardlinkDir walks srcDir and recreates the directory tree under destDir,
+// creating hardlinks for every file found.
+func hardlinkDir(srcDir, destDir string) error {
+	return filepath.WalkDir(srcDir, func(srcPath string, d fs.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+
+		rel, err := filepath.Rel(srcDir, srcPath)
+		if err != nil {
+			return err
+		}
+		destPath := filepath.Join(destDir, rel)
+
+		if d.IsDir() {
+			if err := os.MkdirAll(destPath, 0755); err != nil {
+				return fmt.Errorf("mkdir %q: %w", destPath, err)
+			}
+			return nil
+		}
+
+		return hardlinkFile(srcPath, destPath)
+	})
+}
+
+// hardlinkFile creates a hardlink at destPath pointing to srcPath.
+// It creates parent directories as needed and skips if the link already exists.
+func hardlinkFile(srcPath, destPath string) error {
+	if err := os.MkdirAll(filepath.Dir(destPath), 0755); err != nil {
+		return fmt.Errorf("mkdir %q: %w", filepath.Dir(destPath), err)
+	}
+
+	if _, err := os.Lstat(destPath); err == nil {
+		log.Printf("skip (already exists): %s", destPath)
+		return nil
+	}
+
+	if err := os.Link(srcPath, destPath); err != nil {
+		return fmt.Errorf("hardlink %q -> %q: %w", srcPath, destPath, err)
+	}
+
+	log.Printf("hardlinked: %s -> %s", srcPath, destPath)
+	return nil
+}