2023-09-07 17:31:17 -06:00

123 lines
3.4 KiB
Nim

import std/options
import pkg/upraises
import pkg/chronos
import pkg/questionable
import pkg/questionable/results
import ./key
import ./types
import ./databuffer
export options
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] {.upraises: [], gcsafe, closure.}
IterDispose* = proc(): Future[?!void] {.upraises: [], 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] {.upraises: [], 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)
type
QSortOrder* {.pure.} = enum
Ascending,
Descending
QueryBuffer* = object
key*: KeyBuffer # 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*: QSortOrder # Sort order - not available in all backends
QueryResponseBuffer* = object
key*: KeyBuffer
data*: ValueBuffer
# GetNext* = proc(): Future[?!QueryResponse] {.upraises: [], gcsafe, closure.}
# IterDispose* = proc(): Future[?!void] {.upraises: [], gcsafe.}
# QueryIter* = ref object
# finished*: bool
# next*: GetNext
# dispose*: IterDispose
proc toBuffer*(q: Query): QueryBuffer =
## convert Query to thread-safe QueryBuffer
return QueryBuffer(
key: KeyBuffer.new(q.key),
value: q.value,
offset: q.offset,
sort:
case q.sort:
of SortOrder.Assending: QSortOrder.Ascending
of SortOrder.Descending: QSortOrder.Descending
)
proc toBuffer*(q: QueryResponse): QueryResponseBuffer =
## convert QueryReponses to thread safe type
var kb: KeyBuffer
if q.key.isSome():
kb = KeyBuffer.new(q.key.get())
var kv: KeyBuffer
if q.data.len() > 0:
kv = ValueBuffer.new(q.data)
QueryResponseBuffer(key: kb, data: kv)
proc toQueryResponse*(qb: QueryResponseBuffer): QueryResponse =
## convert QueryReponseBuffer to regular QueryResponse
let key =
if qb.key.isNil: none(Key)
else: some qb.key.toKey().expect("key response should work")
let data =
if qb.data.isNil: EmptyBytes
else: qb.data.toSeq(byte)
(key: key, data: data)
# proc convert*(ret: TResult[QueryResponseBuffer],
# tp: typedesc[QueryResponse]
# ): Result[QueryResponse, ref CatchableError] =
# if ret[].results.isOk():
# result.ok(ret[].results.get().toString())
# else:
# let exc: ref CatchableError = ret[].results.error().toCatchable()
# result.err(exc)