func (env *Env) BeginTxn(parent *Txn, flags uint) (*Txn, error) {
var _txn *C.MDB_txn
var ptxn *C.MDB_txn
if parent == nil {
ptxn = nil
} else {
ptxn = parent._txn
}
ret := C.mdb_txn_begin(env._env, ptxn, C.uint(flags), &_txn)
if ret != SUCCESS {
return nil, Errno(ret)
}
return &Txn{_txn}, nil
}
func (env *Env) BeginTxn(parent *Txn, flags uint) (*Txn, error) {
var _txn *C.MDB_txn
var ptxn *C.MDB_txn
if parent == nil {
ptxn = nil
} else {
ptxn = parent._txn
}
if flags&RDONLY == 0 {
runtime.LockOSThread()
}
ret := C.mdb_txn_begin(env._env, ptxn, C.uint(flags), &_txn)
if ret != SUCCESS {
runtime.UnlockOSThread()
return nil, Errno(ret)
}
return &Txn{_txn}, nil
}
// beginTxn does not lock the OS thread which is a prerequisite for creating a
// write transaction.
func beginTxn(env *Env, parent *Txn, flags uint) (*Txn, error) {
txn := &Txn{
readonly: (flags&Readonly != 0),
env: env,
}
var ptxn *C.MDB_txn
if parent == nil {
ptxn = nil
txn.key = new(C.MDB_val)
txn.val = new(C.MDB_val)
} else {
ptxn = parent._txn
txn.key = parent.key
txn.val = parent.val
}
ret := C.mdb_txn_begin(env._env, ptxn, C.uint(flags), &txn._txn)
if ret != success {
return nil, operrno("mdb_txn_begin", ret)
}
return txn, nil
}
// BeginTxn wraps mdb_txn_begin. http://goo.gl/KoSCV1
//
// BUG: Due to the nature of Go and the lightweight nature of the gomdb API all
// operations on the returned transaction must be made within the caller's
// goroutine to ensure operations are serialized on the same OS thread. This
// same-goroutine restriction also applies to the creation of nested
// transactions.
func (env *Env) BeginTxn(parent *Txn, flags uint) (*Txn, error) {
var _txn *C.MDB_txn
var ptxn *C.MDB_txn
var nested bool
if parent == nil {
ptxn = nil
} else {
nested = true
ptxn = parent._txn
}
// top-level writable transactions must be serialized on an os thread.
if !nested && flags&RDONLY == 0 {
runtime.LockOSThread()
}
ret := C.mdb_txn_begin(env._env, ptxn, C.uint(flags), &_txn)
if ret != SUCCESS {
runtime.UnlockOSThread()
return nil, errno(ret)
}
txn := &Txn{_txn, nested}
return txn, nil
}