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synchronize access to network_pull_date_cache with a queue, writes with barrier flag

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This commit is contained in:
Bryan Montz
2023-05-26 06:38:20 -05:00
parent 61ff7da2ae
commit 7e963c9025
1 changed files with 20 additions and 4 deletions
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24
damus/Nostr/ProfileDatabase.swift
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@@ -19,6 +19,12 @@ final class ProfileDatabase {
private var persistent_container: NSPersistentContainer? private var persistent_container: NSPersistentContainer?
private var background_context: NSManagedObjectContext? private var background_context: NSManagedObjectContext?
private let cache_url: URL private let cache_url: URL
/// This queue is used to synchronize access to the network_pull_date_cache dictionary, which
/// prevents data races from crashing the app.
private var queue = DispatchQueue(label: "io.damus.profile_db",
qos: .userInteractive,
attributes: .concurrent)
private var network_pull_date_cache = [String: Date]() private var network_pull_date_cache = [String: Date]()
init(cache_url: URL = ProfileDatabase.profile_cache_url) { init(cache_url: URL = ProfileDatabase.profile_cache_url) {
@@ -75,7 +81,11 @@ final class ProfileDatabase {
} }
func get_network_pull_date(id: String) -> Date? { func get_network_pull_date(id: String) -> Date? {
if let pull_date = network_pull_date_cache[id] { var pull_date: Date?
queue.sync {
pull_date = network_pull_date_cache[id]
}
if let pull_date {
return pull_date return pull_date
} }
@@ -87,7 +97,9 @@ final class ProfileDatabase {
return nil return nil
} }
network_pull_date_cache[id] = profile.network_pull_date queue.async(flags: .barrier) {
self.network_pull_date_cache[id] = profile.network_pull_date
}
return profile.network_pull_date return profile.network_pull_date
} }
@@ -121,7 +133,9 @@ final class ProfileDatabase {
let pull_date = Date.now let pull_date = Date.now
persisted_profile?.network_pull_date = pull_date persisted_profile?.network_pull_date = pull_date
self.network_pull_date_cache[id] = pull_date self.queue.async(flags: .barrier) {
self.network_pull_date_cache[id] = pull_date
}
try context.save() try context.save()
} }
@@ -146,7 +160,9 @@ final class ProfileDatabase {
throw ProfileDatabaseError.missing_context throw ProfileDatabaseError.missing_context
} }
network_pull_date_cache.removeAll() queue.async(flags: .barrier) {
self.network_pull_date_cache.removeAll()
}
let request = NSFetchRequest<NSFetchRequestResult>(entityName: entity_name) let request = NSFetchRequest<NSFetchRequestResult>(entityName: entity_name)
let batch_delete_request = NSBatchDeleteRequest(fetchRequest: request) let batch_delete_request = NSBatchDeleteRequest(fetchRequest: request)