Explicit preset-file libraries¶

The optional ravet-preset crate connects observable-tree records to an existing consumer-selected directory. PresetLibrary::open canonicalizes that directory, validates state limits and retains an explicit eight-byte product identity. No directory scan, preset selection, default path, watcher, host registration, thread or network action occurs implicitly. Calls allocate/block on control or worker threads. The crate reuses ravet-runtime::files and its existing dependency graph; the portable umbrella and ravet-state gain no runtime dependency.

discover inspects up to 4,096 entries including unrelated files/directories. It returns name-sorted metadata for regular files with the exact .ravetpreset suffix and a valid name, skipping symlinks/directories. Oversized matching files or too many entries reject the complete snapshot. Discovery does not decode records: malformed or foreign-product contents are rejected when selected. Metadata can become stale after external changes; no directory watch is implied.

Names are 1..128 ASCII letters/digits/spaces/underscore/hyphen, with no leading or trailing spaces. Windows reserved device stems reject. This explicit portable file-stem policy performs no sanitization and does not support Unicode display titles, nested preset categories, aliases, renaming or deletion.

save(name, store) encodes and validates the complete product-tagged record against library limits before replacing a same-named file. It reuses runtime same-directory temporary-file atomic replacement, content sync and cleanup. Parent directory sync/power-loss durability and concurrent directory ownership remain outside that contract. No revisions or overwrite prompt are added.

load_into(name, store) bounds the selected file read and validates product, version and library limits before the destination sees any transaction. The destination's limits also apply. Successful restore is one undoable complete edit; malformed/missing/foreign/out-of-bounds records preserve state, revision and undo/redo. The caller then publishes processor-specific parameter snapshots through its control/audio bridge. These files do not implement host factory program indices or CLAP/VST3 preset-discovery extensions.

Filesystem fixtures validate sorting, replacement, complete undoable recall, failed-load history preservation, destination bounds, pre-write rejection, symlink skipping on Unix, name policy and total-entry limits. They use disposable synthetic files on macOS. Other runtime platforms, DAW preset registration and product migration beyond the observable codec remain unvalidated. See decision 0035.