fs-core

Pure-Rust block-device framework. The shared substrate every filesystem driver and disk-image reader plugs into.

What it gives you

• BlockRead — read-only random-access block device (read_at + size_bytes)
• BlockDevice: BlockRead — adds optional write_at / flush / is_writable
• FileDevice — backed by a regular file, optional read-only
• CallbackDevice — backed by host-process-owned callbacks (FFI from Swift / Go / C++)
• CachingDevice — LRU read-cache decorator wrapping any BlockDevice
• A unified Error type with a Custom(String) escape hatch so each driver can lift its own internal errors to the trait boundary

Intended consumers

Filesystem drivers — am-fs-ext4, am-fs-ntfs, future am-fs-exfat, am-fs-hfsplus, am-fs-apfs, am-fs-f2fs, am-fs-btrfs. Each only writes format-specific code; the block plumbing comes from here.

Disk-image readers — am-img-qcow2, future am-img-vhd, am-img-vmdk, am-img-vdi, am-img-sparseimage. Same pattern: format-specific container logic, shared block I/O.

Block-layer utilities — am-partitions (GPT/MBR probe), future am-block-luks, am-block-lvm. Same trait, opposite direction: consumes a BlockRead to expose slices of it.

Layout

src/
  lib.rs              public re-exports
  error.rs            Error / Result
  block.rs            BlockRead + BlockDevice traits
  file_device.rs      FileDevice (backed by std::fs::File)
  callback_device.rs  CallbackDevice (FFI-friendly)
  caching_device.rs   CachingDevice (LRU decorator)
tests/
  cache.rs            CachingDevice + interop tests

License

MIT.