/// An opaque handle to an embedded database.
type Db;
/// A typed view of a database tree (key-value namespace).
///
/// The type parameters 'k and 'v are tracked at compile time, but
/// also stored as metadata in the database. If a tree is reopened
/// with different key or value types, `tree` returns a `DbErr` at
/// run time.
type Tree<'k, 'v>;
mod cursor;
mod txn;
mod subscription;
/// Get the stored type metadata for a tree, or null if none.
/// Pass null for the default tree.
val get_type: fn(Db, [string, null]) -> Result<[(string, string), null], `DbErr(string)>;
/// Open or create an embedded database at the given path.
val open: fn(string) -> Result<Db, `DbErr(string)>;
/// Flush all pending writes to disk.
val flush: fn(Db) -> Result<null, `DbErr(string)>;
/// Generate a monotonically increasing unique u64 ID.
val generate_id: fn(Db) -> Result<u64, `DbErr(string)>;
/// List the names of all trees in the database.
val tree_names: fn(Db) -> Result<Array<string>, `DbErr(string)>;
/// Drop a named tree from the database.
val drop_tree: fn(Db, string) -> Result<bool, `DbErr(string)>;
/// Open or create a named tree with typed keys and values.
/// Pass null for the default (unnamed) tree. The key and value
/// types are recorded on first open; reopening the same tree with
/// different types returns a `DbErr`.
val tree: fn(Db, [string, null]) -> Result<Tree<'k, 'v>, `DbErr(string)>;
/// Get the value for a key, or null if not found.
val get: fn(Tree<'k, 'v>, 'k) -> Result<['v, null], `DbErr(string)>;
/// Insert a key-value pair. Returns the previous value, or null.
val insert: fn(Tree<'k, 'v>, 'k, 'v) -> Result<['v, null], `DbErr(string)>;
/// Remove a key. Returns the previous value, or null.
val remove: fn(Tree<'k, 'v>, 'k) -> Result<['v, null], `DbErr(string)>;
/// Check whether a key exists.
val contains_key: fn(Tree<'k, 'v>, 'k) -> Result<bool, `DbErr(string)>;
/// Batch get values for an array of keys. Returns values in input order, null for missing.
val get_many: fn(Tree<'k, 'v>, Array<'k>) -> Result<Array<['v, null]>, `DbErr(string)>;
/// Get the first (minimum key) entry, or null if empty.
val first: fn(Tree<'k, 'v>) -> Result<[('k, 'v), null], `DbErr(string)>;
/// Get the last (maximum key) entry, or null if empty.
val last: fn(Tree<'k, 'v>) -> Result<[('k, 'v), null], `DbErr(string)>;
/// Atomically remove and return the minimum-key entry.
val pop_min: fn(Tree<'k, 'v>) -> Result<[('k, 'v), null], `DbErr(string)>;
/// Atomically remove and return the maximum-key entry.
val pop_max: fn(Tree<'k, 'v>) -> Result<[('k, 'v), null], `DbErr(string)>;
/// Get the entry with the greatest key strictly less than the given key.
val get_lt: fn(Tree<'k, 'v>, 'k) -> Result<[('k, 'v), null], `DbErr(string)>;
/// Get the entry with the smallest key strictly greater than the given key.
val get_gt: fn(Tree<'k, 'v>, 'k) -> Result<[('k, 'v), null], `DbErr(string)>;
/// Atomic compare-and-swap. Returns null on success,
/// or `Mismatch(current_value) if the current value didn't match.
val compare_and_swap: fn(Tree<'k, 'v>, 'k, ['v, null], ['v, null]) -> Result<[null, `Mismatch(['v, null])], `DbErr(string)>;
/// Atomically apply a batch of inserts and removes.
val batch: fn(Tree<'k, 'v>, Array<[`Insert('k, 'v), `Remove('k)]>) -> Result<null, `DbErr(string)>;
/// Number of entries in the tree (O(n) scan).
val len: fn(Tree<'k, 'v>) -> Result<u64, `DbErr(string)>;
/// True if the tree has no entries.
val is_empty: fn(Tree<'k, 'v>) -> Result<bool, `DbErr(string)>;
/// Total size of the database on disk in bytes.
val size_on_disk: fn(Db) -> Result<u64, `DbErr(string)>;
/// True if the database was recovered after a crash.
val was_recovered: fn(Db) -> Result<bool, `DbErr(string)>;
/// CRC32 checksum of all keys and values (O(n)).
val checksum: fn(Db) -> Result<u32, `DbErr(string)>;
/// Export all database contents to a file.
val export: fn(Db, string) -> Result<null, `DbErr(string)>;
/// Import previously exported data from a file. The database must be empty.
val import: fn(Db, string) -> Result<null, `DbErr(string)>;