nim-datastore/datastore/sql/sqliteds.nim
2023-09-25 16:08:59 -07:00

248 lines
6.5 KiB
Nim

import std/times
import std/options
import pkg/questionable
import pkg/questionable/results
import pkg/sqlite3_abi
from pkg/stew/results as stewResults import isErr
import pkg/upraises
import ../backend
import ./sqlitedsdb
export backend, sqlitedsdb
push: {.upraises: [].}
type
SQLiteBackend* = object
db: SQLiteDsDb
proc path*(self: SQLiteBackend): string =
$self.db.dbPath
proc readOnly*(self: SQLiteBackend): bool = self.db.readOnly
proc timestamp*(t = epochTime()): int64 =
(t * 1_000_000).int64
proc has*(self: SQLiteBackend, key: DbKey): ?!bool =
var
exists = false
key = $key
proc onData(s: RawStmtPtr) =
exists = sqlite3_column_int64(s, ContainsStmtExistsCol.cint).bool
if err =? self.db.containsStmt.query((key), onData).errorOption:
return failure err
return success exists
proc delete*(self: SQLiteBackend, key: DbKey): ?!void =
return self.db.deleteStmt.exec(($key))
proc delete*(self: SQLiteBackend, keys: openArray[DbKey]): ?!void =
if err =? self.db.beginStmt.exec().errorOption:
return failure(err)
for key in keys:
if err =? self.db.deleteStmt.exec(($key)).errorOption:
if err =? self.db.rollbackStmt.exec().errorOption:
return failure err.msg
return failure err.msg
if err =? self.db.endStmt.exec().errorOption:
return failure err.msg
return success()
proc get*(self: SQLiteBackend, key: DbKey): ?!seq[byte] =
# see comment in ./filesystem_datastore re: finer control of memory
# allocation in `proc get`, could apply here as well if bytes were read
# incrementally with `sqlite3_blob_read`
var
bytes: seq[byte]
proc onData(s: RawStmtPtr) =
bytes = dataCol(self.db.getDataCol)
if err =? self.db.getStmt.query(($key), onData).errorOption:
return failure(err)
if bytes.len <= 0:
return failure(
newException(DatastoreKeyNotFound, "DbKey doesn't exist"))
return success bytes
proc put*(self: SQLiteBackend, key: DbKey, data: DbVal): ?!void =
when DbVal is seq[byte]:
return self.db.putStmt.exec((key, data, timestamp()))
elif DbVal is DataBuffer:
return self.db.putBufferStmt.exec((key, data, timestamp()))
else:
{.error: "unknown type".}
proc put*(self: SQLiteBackend, batch: openArray[DbBatchEntry]): ?!void =
if err =? self.db.beginStmt.exec().errorOption:
return failure err
for entry in batch:
when entry.key is string:
let putStmt = self.db.putStmt
elif entry.key is KeyId:
let putStmt = self.db.putBufferStmt
else:
{.error: "unhandled type".}
if err =? putStmt.exec((entry.key, entry.data, timestamp())).errorOption:
if err =? self.db.rollbackStmt.exec().errorOption:
return failure err
return failure err
if err =? self.db.endStmt.exec().errorOption:
return failure err
return success()
proc close*(self: SQLiteBackend): ?!void =
self.db.close()
return success()
proc query*(
self: SQLiteBackend,
query: DbQuery
): Result[DbQueryHandle[RawStmtPtr], ref CatchableError] =
var
queryStr = if query.value:
QueryStmtDataIdStr
else:
QueryStmtIdStr
if query.sort == SortOrder.Descending:
queryStr &= QueryStmtOrderDescending
else:
queryStr &= QueryStmtOrderAscending
if query.limit != 0:
queryStr &= QueryStmtLimit
if query.offset != 0:
queryStr &= QueryStmtOffset
let
queryStmt = QueryStmt.prepare(
self.db.env, queryStr).expect("should not fail")
s = RawStmtPtr(queryStmt)
queryKey = $query.key & "*"
var
v = sqlite3_bind_text(
s, 1.cint, queryKey.cstring, queryKey.len().cint, SQLITE_TRANSIENT_GCSAFE)
if not (v == SQLITE_OK):
return failure newException(DatastoreError, $sqlite3_errstr(v))
if query.limit != 0:
v = sqlite3_bind_int(s, 2.cint, query.limit.cint)
if not (v == SQLITE_OK):
return failure newException(DatastoreError, $sqlite3_errstr(v))
if query.offset != 0:
v = sqlite3_bind_int(s, 3.cint, query.offset.cint)
if not (v == SQLITE_OK):
return failure newException(DatastoreError, $sqlite3_errstr(v))
success DbQueryHandle[RawStmtPtr](query: query, env: s)
proc close*(handle: var DbQueryHandle[RawStmtPtr]) =
if not handle.closed:
handle.closed = true
echo "sqlite backend: query: finally close"
discard sqlite3_reset(handle.env)
discard sqlite3_clear_bindings(handle.env)
handle.env.dispose()
iterator iter*(handle: var DbQueryHandle[RawStmtPtr]): ?!DbQueryResponse =
while not handle.cancel:
let v = sqlite3_step(handle.env)
case v
of SQLITE_ROW:
echo "SQLITE ROW"
let
key = KeyId.new(sqlite3_column_text_not_null(handle.env, QueryStmtIdCol))
blob: ?pointer =
if handle.query.value: sqlite3_column_blob(handle.env, QueryStmtDataCol).some
else: pointer.none
# detect out-of-memory error
# see the conversion table and final paragraph of:
# https://www.sqlite.org/c3ref/column_blob.html
# see also https://www.sqlite.org/rescode.html
# the "data" column can be NULL so in order to detect an out-of-memory
# error it is necessary to check that the result is a null pointer and
# that the result code is an error code
if blob.isSome and blob.get().isNil:
echo "BLOB: isSome"
let v = sqlite3_errcode(sqlite3_db_handle(handle.env))
if not (v in [SQLITE_OK, SQLITE_ROW, SQLITE_DONE]):
handle.cancel = true
yield DbQueryResponse.failure newException(DatastoreError, $sqlite3_errstr(v))
let
dataLen = sqlite3_column_bytes(handle.env, QueryStmtDataCol)
data =
if blob.isSome:
let arr = cast[ptr UncheckedArray[byte]](blob)
DataBuffer.new(arr.toOpenArray(0, dataLen-1))
else: DataBuffer.new("")
echo "SQLITE ROW: yield"
yield success (key.some, data)
of SQLITE_DONE:
echo "SQLITE DONE: yield"
handle.close()
break
else:
echo "SQLITE ERROR: yield"
handle.cancel = true
yield DbQueryResponse.failure newException(DatastoreError, $sqlite3_errstr(v))
break
handle.close()
proc contains*(self: SQLiteBackend, key: DbKey): bool =
return self.has(key).get()
proc new*(T: type SQLiteBackend,
path: string,
readOnly = false): ?!SQLiteBackend =
let
flags =
if readOnly: SQLITE_OPEN_READONLY
else: SQLITE_OPEN_READWRITE or SQLITE_OPEN_CREATE
success SQLiteBackend(db: ? SQLiteDsDb.open(path, flags))
proc new*(T: type SQLiteBackend,
db: SQLiteDsDb): ?!T =
success SQLiteBackend(db: db)