This adds a sync mechanism in Ndb.swift to coordinate certain usage of
nostrdb.c calls and the need to close nostrdb due to app lifecycle
requirements. Furthermore, it fixes the order of operations when
re-opening NostrDB, to avoid race conditions where a query uses an older
Ndb generation.
This sync mechanism allows multiple queries to happen simultaneously
(from the Swift-side), while preventing ndb from simultaneously closing
during such usages. It also does that while keeping the Ndb interface
sync and nonisolated, which keeps the API easy to use from
Swift/SwiftUI and allows for parallel operations to occur.
If Swift Actors were to be used (e.g. creating an NdbActor), the Ndb.swift
interface would change in such a way that it would propagate the need for
several changes throughout the codebase, including loading logic in
some ViewModels. Furthermore, it would likely decrease performance by
forcing Ndb.swift operations to run sequentially when they could run in
parallel.
Changelog-Fixed: Fixed crashes that happened when the app went into background mode
Closes: https://github.com/damus-io/damus/issues/3245
Signed-off-by: Daniel D’Aquino <daniel@daquino.me>
This commit redesigns the Ndb.swift interface with a focus on build-time
safety against crashes.
It removes the external usage of NdbTxn and SafeNdbTxn, restricting it
to be used only in NostrDB internal code.
This prevents dangerous and crash prone usages throughout the app, such
as holding transactions in a variable in an async function (which can
cause thread-based reference counting to incorrectly deinit inherited
transactions in use by separate callers), as well as holding unsafe
unowned values longer than the lifetime of their corresponding
transactions.
Closes: https://github.com/damus-io/damus/issues/3364
Changelog-Fixed: Fixed several crashes throughout the app
Signed-off-by: Daniel D’Aquino <daniel@daquino.me>
Huge refactor to add better structure to the project.
Separating features with their associated view and model structure.
This should be better organization and will allow us to improve the
overall architecture in the future.
I forsee many more improvements that can follow this change. e.g. MVVM Arch
As well as cleaning up duplicate, unused, functionality.
Many files have global functions that can also be moved or be renamed.
damus/
├── Features/
│ ├── <Feature>/
│ │ ├── Views/
│ │ └── Models/
├── Shared/
│ ├── Components/
│ ├── Media/
│ ├── Buttons/
│ ├── Extensions/
│ ├── Empty Views/
│ ├── ErrorHandling/
│ ├── Modifiers/
│ └── Utilities/
├── Core/
│ ├── Nostr/
│ ├── NIPs/
│ ├── DIPs/
│ ├── Types/
│ ├── Networking/
│ └── Storage/
Signed-off-by: ericholguin <ericholguin@apache.org>
Daniel D’Aquino