Snapshots | UStore for C++

API

snapshot_tA point-in-time view of the whole database, which reads through it see until its destructor frees it.

class snapshot_t

It owns its handle, never copies, and holds its database open until destroyed, so it may outlive its database_t.

Classsnapshot_ref_tA point-in-time view of the whole database, as the calls on one executor see it, without owning either.7

class snapshot_ref_t

It hands out read-only collections and proxies.

snapshot_ref_t

snapshot_ref_t() noexcept=default;

snapshot_ref_t(receiver_t receiver) noexcept;

onThe same snapshot, running every call on executor.

snapshot_ref_t on(ustore_executor_t executor) const noexcept;

deferredThe same snapshot, whose verbs submit to executor and answer deferred calls.

deferred_snapshot_t deferred(ustore_executor_t executor) const noexcept;

collectionsLists the collections at the snapshot, with their identifiers in arena.

expected<collections_list_t> collections(arena_t & arena) noexcept;

containsWhether a collection named name exists at the snapshot.

expected<bool> contains(std::string_view name) noexcept;

findOpens a read-only view of one collection at the snapshot.

template <typename collection_type_ = blobs_collection_t>
expected<typename collection_type_::read_only_t> find(
    std::string_view name) noexcept;

saveSaves the snapshot as a new database at path, reporting the bytes saved to progress, which may cancel the save and so remove what it wrote.

status_t save(
    std::string_view path,
    progress_arg_t progress = {}) noexcept;