2023-09-10 17:16:50 +00:00
|
|
|
//
|
|
|
|
// NdbTx.swift
|
|
|
|
// damus
|
|
|
|
//
|
|
|
|
// Created by William Casarin on 2023-08-30.
|
|
|
|
//
|
|
|
|
|
|
|
|
import Foundation
|
|
|
|
|
|
|
|
#if TXNDEBUG
|
|
|
|
fileprivate var txn_count: Int = 0
|
|
|
|
#endif
|
|
|
|
|
|
|
|
// Would use struct and ~Copyable but generics aren't supported well
|
|
|
|
class NdbTxn<T> {
|
|
|
|
var txn: ndb_txn
|
|
|
|
private var val: T!
|
|
|
|
var moved: Bool
|
2023-12-04 19:52:39 +00:00
|
|
|
var inherited: Bool
|
2023-09-10 17:16:50 +00:00
|
|
|
|
2023-09-10 21:51:55 +00:00
|
|
|
init(ndb: Ndb, with: (NdbTxn<T>) -> T = { _ in () }) {
|
2023-09-10 17:16:50 +00:00
|
|
|
#if TXNDEBUG
|
|
|
|
txn_count += 1
|
|
|
|
print("opening transaction \(txn_count)")
|
|
|
|
#endif
|
2023-12-04 19:52:39 +00:00
|
|
|
if let active_txn = Thread.current.threadDictionary["ndb_txn"] as? ndb_txn {
|
|
|
|
// some parent thread is active, use that instead
|
|
|
|
self.txn = active_txn
|
|
|
|
self.inherited = true
|
|
|
|
} else {
|
|
|
|
self.txn = ndb_txn()
|
|
|
|
let _ = ndb_begin_query(ndb.ndb.ndb, &self.txn)
|
|
|
|
Thread.current.threadDictionary["ndb_txn"] = self.txn
|
|
|
|
self.inherited = false
|
|
|
|
}
|
2023-09-10 17:16:50 +00:00
|
|
|
self.moved = false
|
|
|
|
self.val = with(self)
|
|
|
|
}
|
|
|
|
|
2023-12-04 19:52:39 +00:00
|
|
|
private init(txn: ndb_txn, val: T) {
|
2023-09-10 17:16:50 +00:00
|
|
|
self.txn = txn
|
|
|
|
self.val = val
|
|
|
|
self.moved = false
|
2023-12-04 19:52:39 +00:00
|
|
|
self.inherited = false
|
2023-09-10 17:16:50 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/// Only access temporarily! Do not store database references for longterm use. If it's a primitive type you
|
|
|
|
/// can retrieve this value with `.value`
|
|
|
|
var unsafeUnownedValue: T {
|
|
|
|
precondition(!moved)
|
|
|
|
return val
|
|
|
|
}
|
|
|
|
|
|
|
|
deinit {
|
2023-12-04 19:52:39 +00:00
|
|
|
if moved || inherited {
|
|
|
|
return
|
2023-09-10 17:16:50 +00:00
|
|
|
}
|
2023-12-04 19:52:39 +00:00
|
|
|
|
|
|
|
#if TXNDEBUG
|
|
|
|
txn_count -= 1;
|
|
|
|
print("closing transaction \(txn_count)")
|
|
|
|
#endif
|
|
|
|
ndb_end_query(&self.txn)
|
|
|
|
Thread.current.threadDictionary.removeObject(forKey: "ndb_txn")
|
2023-09-10 17:16:50 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
// functor
|
|
|
|
func map<Y>(_ transform: (T) -> Y) -> NdbTxn<Y> {
|
|
|
|
self.moved = true
|
|
|
|
return .init(txn: self.txn, val: transform(val))
|
|
|
|
}
|
|
|
|
|
|
|
|
// comonad!?
|
|
|
|
// useful for moving ownership of a transaction to another value
|
|
|
|
func extend<Y>(_ with: (NdbTxn<T>) -> Y) -> NdbTxn<Y> {
|
|
|
|
self.moved = true
|
|
|
|
return .init(txn: self.txn, val: with(self))
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
protocol OptionalType {
|
|
|
|
associatedtype Wrapped
|
|
|
|
var optional: Wrapped? { get }
|
|
|
|
}
|
|
|
|
|
|
|
|
extension Optional: OptionalType {
|
|
|
|
typealias Wrapped = Wrapped
|
|
|
|
|
|
|
|
var optional: Wrapped? {
|
|
|
|
return self
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
extension NdbTxn where T: OptionalType {
|
|
|
|
func collect() -> NdbTxn<T.Wrapped>? {
|
|
|
|
guard let unwrappedVal: T.Wrapped = val.optional else {
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
self.moved = true
|
|
|
|
return NdbTxn<T.Wrapped>(txn: self.txn, val: unwrappedVal)
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
extension NdbTxn where T == Bool { var value: T { return self.unsafeUnownedValue } }
|
|
|
|
extension NdbTxn where T == Bool? { var value: T { return self.unsafeUnownedValue } }
|
|
|
|
extension NdbTxn where T == Int { var value: T { return self.unsafeUnownedValue } }
|
|
|
|
extension NdbTxn where T == Int? { var value: T { return self.unsafeUnownedValue } }
|
|
|
|
extension NdbTxn where T == Double { var value: T { return self.unsafeUnownedValue } }
|
|
|
|
extension NdbTxn where T == Double? { var value: T { return self.unsafeUnownedValue } }
|
|
|
|
extension NdbTxn where T == UInt64 { var value: T { return self.unsafeUnownedValue } }
|
|
|
|
extension NdbTxn where T == UInt64? { var value: T { return self.unsafeUnownedValue } }
|
|
|
|
extension NdbTxn where T == String { var value: T { return self.unsafeUnownedValue } }
|
|
|
|
extension NdbTxn where T == String? { var value: T { return self.unsafeUnownedValue } }
|
|
|
|
extension NdbTxn where T == NoteId? { var value: T { return self.unsafeUnownedValue } }
|
|
|
|
extension NdbTxn where T == NoteId { var value: T { return self.unsafeUnownedValue } }
|