nimbus-eth2/beacon_chain/kvstore_lmdb.nim

161 lines
4.2 KiB
Nim

## Implementation of KVStore based on LMDB
## TODO: crashes on win32, investigate
import os
import ./kvstore
{.compile: "../vendor/lmdb/libraries/liblmdb/mdb.c".}
{.compile: "../vendor/lmdb/libraries/liblmdb/midl.c".}
const
MDB_NOSUBDIR = 0x4000
MDB_RDONLY = 0x20000
MDB_NOTFOUND = -30798
when defined(cpu64):
const LMDB_MAP_SIZE = 1024'u * 1024'u * 1024'u * 10'u # 10TB enough?
else:
const LMDB_MAP_SIZE = 1024'u * 1024'u * 1024'u # 32bit limitation
type
MDB_Env = distinct pointer
MDB_Txn = distinct pointer
MDB_Dbi = distinct cuint
MDB_val = object
mv_size: uint
mv_data: pointer
LmdbError* = object of CatchableError
# Used subset of the full LMDB API
proc mdb_env_create(env: var MDB_Env): cint {.importc, cdecl.}
proc mdb_env_open(env: MDB_Env, path: cstring, flags: cuint, mode: cint): cint {.importc, cdecl.}
proc mdb_txn_begin(env: MDB_Env, parent: MDB_Txn, flags: cuint, txn: var MDB_Txn): cint {.importc, cdecl.}
proc mdb_txn_commit(txn: MDB_Txn): cint {.importc, cdecl.}
proc mdb_txn_abort(txn: MDB_Txn) {.importc, cdecl.}
proc mdb_dbi_open(txn: MDB_Txn, name: cstring, flags: cuint, dbi: var MDB_Dbi): cint {.importc, cdecl.}
proc mdb_env_close(env: MDB_Env) {.importc, cdecl.}
proc mdb_strerror(err: cint): cstring {.importc, cdecl.}
proc mdb_get(txn: MDB_Txn, dbi: MDB_Dbi, key: var MDB_val, data: var MDB_val): cint {.importc, cdecl.}
proc mdb_del(txn: MDB_Txn, dbi: MDB_Dbi, key: var MDB_val, data: ptr MDB_val): cint {.importc, cdecl.}
proc mdb_put(txn: MDB_Txn, dbi: MDB_Dbi, key: var MDB_val, data: var MDB_val, flags: cuint): cint {.importc, cdecl.}
proc mdb_env_set_mapsize(env: MDB_Env, size: uint64): cint {.importc, cdecl.}
func raiseLmdbError(err: cint) {.noreturn.} =
let tmp = mdb_strerror(err)
raise (ref LmdbError)(msg: $tmp)
type
LmdbStoreRef* = ref object of RootObj
env: MDB_Env
template init(T: type MDB_Val, val: openArray[byte]): T =
T(
mv_size: val.len.uint,
mv_data: unsafeAddr val[0]
)
proc begin(db: LmdbStoreRef, flags: cuint): tuple[txn: MDB_Txn, dbi: MDB_Dbi] =
var
txn: MDB_Txn
dbi: MDB_Dbi
if (let x = mdb_txn_begin(db.env, nil, flags, txn); x != 0):
raiseLmdbError(x)
if (let x = mdb_dbi_open(txn, nil, 0, dbi); x != 0):
mdb_txn_abort(txn)
raiseLmdbError(x)
(txn, dbi)
proc get*(db: LmdbStoreRef, key: openarray[byte], onData: DataProc): bool =
if key.len == 0:
return
var
(txn, dbi) = db.begin(MDB_RDONLY)
dbKey = MDB_Val.init(key)
dbVal: MDB_val
# abort ok for read-only and easier for exception safety
defer: mdb_txn_abort(txn)
if (let x = mdb_get(txn, dbi, dbKey, dbVal); x != 0):
if x == MDB_NOTFOUND:
return false
raiseLmdbError(x)
if not onData.isNil:
onData(toOpenArrayByte(cast[cstring](dbVal.mv_data), 0, dbVal.mv_size.int - 1))
true
proc put*(db: LmdbStoreRef, key, value: openarray[byte]) =
if key.len == 0: return
var
(txn, dbi) = db.begin(0)
dbKey = MDB_Val.init(key)
dbVal = MDB_Val.init(value)
if (let x = mdb_put(txn, dbi, dbKey, dbVal, 0); x != 0):
mdb_txn_abort(txn)
raiseLmdbError(x)
if (let x = mdb_txn_commit(txn); x != 0):
raiseLmdbError(x)
proc contains*(db: LmdbStoreRef, key: openarray[byte]): bool =
db.get(key, nil)
proc del*(db: LmdbStoreRef, key: openarray[byte]) =
if key.len == 0: return
var
(txn, dbi) = db.begin(0)
dbKey = MDB_Val.init(key)
if (let x = mdb_del(txn, dbi, dbKey, nil); x != 0):
mdb_txn_abort(txn)
if x != MDB_NOTFOUND:
raiseLmdbError(x)
return
if (let x = mdb_txn_commit(txn); x != 0):
raiseLmdbError(x)
proc close*(db: LmdbStoreRef) =
mdb_env_close(db.env)
proc init*(T: type LmdbStoreRef, basePath: string, readOnly = false): T =
var
env: MDB_Env
if (let x = mdb_env_create(env); x != 0):
raiseLmdbError(x)
createDir(basePath)
let dataDir = basePath / "nimbus.lmdb"
if (let x = mdb_env_set_mapsize(env, LMDB_MAP_SIZE); x != 0):
mdb_env_close(env)
raiseLmdbError(x)
var openFlags = MDB_NOSUBDIR
if readOnly: openFlags = openFlags or MDB_RDONLY
# file mode ignored on windows
if (let x = mdb_env_open(env, dataDir, openFlags.cuint, 0o664.cint); x != 0):
mdb_env_close(env)
raiseLmdbError(x)
T(env: env)