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txn: fix subtle transaction inheritence bugs

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This fixes subtle bugs with transaction inheritence. Since we were not
passing the inherited state to moved value, we were sometimes committing
transactions more than once.

Changelog-Fixed: Fix many nostrdb transaction related crashes
This commit is contained in:
William Casarin
2024-01-26 14:03:49 -08:00
parent f190b6414c
commit e3642b92d1
8 changed files with 53 additions and 42 deletions
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46
nostrdb/NdbTxn.swift
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@@ -19,17 +19,16 @@ class NdbTxn<T> {
var inherited: Bool
var ndb: Ndb
var generation: Int
var name: String
init?(ndb: Ndb, with: (NdbTxn<T>) -> T = { _ in () }) {
guard !ndb.closed else { return nil }
init?(ndb: Ndb, with: (NdbTxn<T>) -> T = { _ in () }, name: String? = nil) {
guard !ndb.is_closed else { return nil }
self.name = name ?? "txn"
self.ndb = ndb
self.generation = ndb.generation
#if TXNDEBUG
txn_count += 1
print("opening transaction \(txn_count)")
#endif
if let active_txn = Thread.current.threadDictionary["ndb_txn"] as? ndb_txn {
// some parent thread is active, use that instead
print("txn: inherited txn")
self.txn = active_txn
self.inherited = true
self.generation = Thread.current.threadDictionary["txn_generation"] as! Int
@@ -37,6 +36,9 @@ class NdbTxn<T> {
self.txn = ndb_txn()
guard !ndb.is_closed else { return nil }
self.generation = ndb.generation
#if TXNDEBUG
txn_count += 1
#endif
let ok = ndb_begin_query(ndb.ndb.ndb, &self.txn) != 0
if !ok {
return nil
@@ -46,17 +48,21 @@ class NdbTxn<T> {
Thread.current.threadDictionary["txn_generation"] = ndb.generation
self.inherited = false
}
#if TXNDEBUG
print("txn: open gen\(self.generation) '\(self.name)' \(txn_count)")
#endif
self.moved = false
self.val = with(self)
}
private init(ndb: Ndb, txn: ndb_txn, val: T) {
private init(ndb: Ndb, txn: ndb_txn, val: T, generation: Int, inherited: Bool, name: String) {
self.txn = txn
self.val = val
self.moved = false
self.inherited = false
self.inherited = inherited
self.ndb = ndb
self.generation = 0
self.generation = generation
self.name = name
}
/// Only access temporarily! Do not store database references for longterm use. If it's a primitive type you
@@ -68,32 +74,42 @@ class NdbTxn<T> {
deinit {
if self.generation != ndb.generation {
//print("txn: OLD GENERATION (\(self.generation) != \(ndb.generation)), IGNORING")
print("txn: OLD GENERATION (\(self.generation) != \(ndb.generation)), IGNORING")
return
}
if moved || inherited || ndb.closed {
if inherited {
print("txn: not closing. inherited ")
return
}
if moved {
//print("txn: not closing. moved")
return
}
if ndb.is_closed {
print("txn: not closing. db closed")
return
}
#if TXNDEBUG
txn_count -= 1;
print("txn: closing transaction \(txn_count)")
print("txn: close gen\(generation) '\(name)' \(txn_count)")
#endif
ndb_end_query(&self.txn)
//self.skip_close = true
Thread.current.threadDictionary.removeObject(forKey: "ndb_txn")
}
// functor
func map<Y>(_ transform: (T) -> Y) -> NdbTxn<Y> {
self.moved = true
return .init(ndb: self.ndb, txn: self.txn, val: transform(val))
return .init(ndb: self.ndb, txn: self.txn, val: transform(val), generation: generation, inherited: inherited, name: self.name)
}
// 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(ndb: self.ndb, txn: self.txn, val: with(self))
return .init(ndb: self.ndb, txn: self.txn, val: with(self), generation: generation, inherited: inherited, name: self.name)
}
}
@@ -116,7 +132,7 @@ extension NdbTxn where T: OptionalType {
return nil
}
self.moved = true
return NdbTxn<T.Wrapped>(ndb: self.ndb, txn: self.txn, val: unwrappedVal)
return NdbTxn<T.Wrapped>(ndb: self.ndb, txn: self.txn, val: unwrappedVal, generation: generation, inherited: inherited, name: name)
}
}