nim-datastore/datastore/query.nim

57 lines
1.3 KiB
Nim

{.push raises: [].}
import pkg/chronos
import pkg/questionable
import pkg/questionable/results
import ./key
import ./types
type
SortOrder* {.pure.} = enum
Assending,
Descending
Query* = object
key*: Key # Key to be queried
value*: bool # Flag to indicate if data should be returned
limit*: int # Max items to return - not available in all backends
offset*: int # Offset from which to start querying - not available in all backends
sort*: SortOrder # Sort order - not available in all backends
QueryResponse* = tuple[key: ?Key, data: seq[byte]]
QueryEndedError* = object of DatastoreError
GetNext* = proc(): Future[?!QueryResponse] {.raises: [], gcsafe, closure.}
IterDispose* = proc(): Future[?!void] {.raises: [], gcsafe.}
QueryIter* = ref object
finished*: bool
next*: GetNext
dispose*: IterDispose
iterator items*(q: QueryIter): Future[?!QueryResponse] =
while not q.finished:
yield q.next()
proc defaultDispose(): Future[?!void] {.gcsafe, async.} =
return success()
proc new*(T: type QueryIter, dispose = defaultDispose): T =
QueryIter(dispose: dispose)
proc init*(
T: type Query,
key: Key,
value = true,
sort = SortOrder.Assending,
offset = 0,
limit = -1): T =
T(
key: key,
value: value,
sort: sort,
offset: offset,
limit: limit)