Source
A source is a file discovered on disk during scanning. Canon tracks:
- Location: Root path + relative path within the root
- Identity: Device ID and inode for move detection
- Metadata: Size and modification time
- Integrity: Partial hash (first + last 8KB) for validation during transfers
- State: A
basis_revcounter that increments when size or mtime changes
Sources represent where files are found. Multiple sources can point to the same content (see Object) when files are duplicated across locations.
When a source is scanned with hashing enabled (the default), Canon computes its SHA-256 hash and links it to an object. This enables deduplication and archive tracking.
Exclusion
Sources can be marked as excluded to skip them during archiving. A source is considered excluded if:
- The source itself is marked excluded, OR
- The source’s linked object is marked excluded
Excluding an object therefore excludes every source with that content, regardless of where it appears.