72 lines
4.4 KiB
Markdown
72 lines
4.4 KiB
Markdown
# Inventory models, hierarchy, and cache
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The native inventory layer mirrors the value and hierarchy behavior of
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LibreMetaverse's `InventoryBase`, `InventoryItem`, `InventoryFolder`,
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`InventoryNode`, and `Inventory` types without depending on a network
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transport. Concrete item subclasses remain concrete when inserted, queried,
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notified, or restored from disk; link detection is based on `AssetType`, not on
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the Rust wrapper type. This preserves the C# misclassified-link behavior.
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Store mutation is serialized by one inventory state lock. Parent/child and link
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indexes and recursive item counts are rebuilt as one transaction, with cycle
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and depth bounds. Missing parents become placeholder folders until their real
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folder record arrives. Self-loops and longer parent cycles remain queryable but
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are not linked into a cyclic ownership graph. Removing a folder removes its
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bounded descendant subtree. Root and library roots are tracked independently,
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and direct system folders can be found by `FolderType`. Sorting supports the
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`ByDate`, `FoldersByName`, and `SystemFoldersToTop` flags.
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Added, updated, and removed notifications clone their arguments and subscriber
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list before invoking observers. No inventory, node, or subscriber lock is held
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during a callback, so observers may safely query or mutate the store. A panic
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in one observer is isolated by the shared event registry.
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Cache files start with `INVCACHE`, a little-endian format version, owner and
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root identities, and tagged concrete records. Reads are limited to 64 MiB,
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one million records, one MiB per string, and a 512-level hierarchy. Invalid
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magic, versions, UTF-8, enums, duplicate IDs, zero IDs, truncated records, and
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trailing data are rejected before the live store is replaced. Synchronous
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restore returns `-1` for compatibility; asynchronous restore returns the typed
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error. Saves snapshot under the state lock, release it before I/O, write and
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sync a same-directory temporary file, then replace the destination. The
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replacement includes a rollback path on platforms that cannot rename over an
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existing file.
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The focused compatibility suites are
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`inventory_store_semantics` and `misclassified_link_semantics`; native unit
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tests additionally cover concrete cache round trips, permissions, corruption,
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unknown versions, system-folder sorting, and callback re-entry.
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## UDP inventory manager
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`InventoryManager` now owns the live inventory protocol boundary. Login installs
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the agent and library skeletons in the transport-free store, while validated
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`UpdateCreateInventoryItem`, `BulkUpdateInventory`, `FetchInventoryReply`, and
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`InventoryDescendents` replies populate or reconcile it. Create and copy callback
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IDs, item fetches, task replies, and inventory offers are correlated independently;
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cancelling one waiter removes only that waiter. A cleanup worker bounds abandoned
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requests to one minute, and the manager rejects more than 4,096 pending operations.
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Outbound create, update, move, copy, remove, give, rez/derez, script-state, and
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task-inventory operations build the generated protocol packet types. Generated
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multi-block packets use the packet codec's `encode_multiple` path, so large batches
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are split according to the UDP transport bounds while retaining the same agent,
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session, transaction, callback, owner, and permission data. Capability-backed
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inventory fetch and folder-content responses are parsed before becoming visible in
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the store. Asset, material, script, notecard, and thumbnail upload bodies remain a
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separate asset-pipeline concern.
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Legacy task inventory uses a correlated `ReplyTaskInventory` filename followed by
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a `RequestXfer` transfer. The implementation confirms packets, handles duplicate
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or out-of-order packet numbers deterministically, aborts cancelled transfers, and
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rejects announced or accumulated data above 16 MiB. Task text parsing is capped at
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100,000 entries and accepts both plain asset IDs and the reference shadow-ID XOR
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encoding. The capability path applies the same byte and entry limits.
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No store lock is held across an await, a packet send, or an observer callback.
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Reply data is decoded and validated before store mutation, and event registries
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snapshot subscribers before invoking them. Focused coverage lives in
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`inventory_manager_semantics`, `task_inventory_semantics`, and the native
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`inventory_manager::tests` fake-packet cases for callback isolation, bulk-copy
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completion, stale folder versions, offers, capability events, and bounded Xfer.
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