diff options
Diffstat (limited to 'third_party/rust/sync15/src/client/coll_state.rs')
| -rw-r--r-- | third_party/rust/sync15/src/client/coll_state.rs | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/third_party/rust/sync15/src/client/coll_state.rs b/third_party/rust/sync15/src/client/coll_state.rs new file mode 100644 index 0000000000..df8be5f5b5 --- /dev/null +++ b/third_party/rust/sync15/src/client/coll_state.rs @@ -0,0 +1,354 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +use super::request::InfoConfiguration; +use super::{CollectionKeys, GlobalState}; +use crate::engine::{CollSyncIds, EngineSyncAssociation, SyncEngine}; +use crate::error; +use crate::KeyBundle; +use crate::ServerTimestamp; + +/// Holds state for a collection. In general, only the CollState is +/// needed to sync a collection (but a valid GlobalState is needed to obtain +/// a CollState) +#[derive(Debug, Clone)] +pub struct CollState { + pub config: InfoConfiguration, + // initially from meta/global, updated after an xius POST/PUT. + pub last_modified: ServerTimestamp, + pub key: KeyBundle, +} + +#[derive(Debug)] +pub enum LocalCollState { + /// The state is unknown, with the EngineSyncAssociation the collection + /// reports. + Unknown { assoc: EngineSyncAssociation }, + + /// The engine has been declined. This is a "terminal" state. + Declined, + + /// There's no such collection in meta/global. We could possibly update + /// meta/global, but currently all known collections are there by default, + /// so this is, basically, an error condition. + NoSuchCollection, + + /// Either the global or collection sync ID has changed - we will reset the engine. + SyncIdChanged { ids: CollSyncIds }, + + /// The collection is ready to sync. + Ready { key: KeyBundle }, +} + +pub struct LocalCollStateMachine<'state> { + global_state: &'state GlobalState, + root_key: &'state KeyBundle, +} + +impl<'state> LocalCollStateMachine<'state> { + fn advance( + &self, + from: LocalCollState, + engine: &dyn SyncEngine, + ) -> error::Result<LocalCollState> { + let name = &engine.collection_name().to_string(); + let meta_global = &self.global_state.global; + match from { + LocalCollState::Unknown { assoc } => { + if meta_global.declined.contains(name) { + return Ok(LocalCollState::Declined); + } + match meta_global.engines.get(name) { + Some(engine_meta) => match assoc { + EngineSyncAssociation::Disconnected => Ok(LocalCollState::SyncIdChanged { + ids: CollSyncIds { + global: meta_global.sync_id.clone(), + coll: engine_meta.sync_id.clone(), + }, + }), + EngineSyncAssociation::Connected(ref ids) + if ids.global == meta_global.sync_id + && ids.coll == engine_meta.sync_id => + { + let coll_keys = CollectionKeys::from_encrypted_payload( + self.global_state.keys.clone(), + self.global_state.keys_timestamp, + self.root_key, + )?; + Ok(LocalCollState::Ready { + key: coll_keys.key_for_collection(name).clone(), + }) + } + _ => Ok(LocalCollState::SyncIdChanged { + ids: CollSyncIds { + global: meta_global.sync_id.clone(), + coll: engine_meta.sync_id.clone(), + }, + }), + }, + None => Ok(LocalCollState::NoSuchCollection), + } + } + + LocalCollState::Declined => unreachable!("can't advance from declined"), + + LocalCollState::NoSuchCollection => unreachable!("the collection is unknown"), + + LocalCollState::SyncIdChanged { ids } => { + let assoc = EngineSyncAssociation::Connected(ids); + log::info!("Resetting {} engine", engine.collection_name()); + engine.reset(&assoc)?; + Ok(LocalCollState::Unknown { assoc }) + } + + LocalCollState::Ready { .. } => unreachable!("can't advance from ready"), + } + } + + // A little whimsy - a portmanteau of far and fast + fn run_and_run_as_farst_as_you_can( + &mut self, + engine: &dyn SyncEngine, + ) -> error::Result<Option<CollState>> { + let mut s = LocalCollState::Unknown { + assoc: engine.get_sync_assoc()?, + }; + // This is a simple state machine and should never take more than + // 10 goes around. + let mut count = 0; + loop { + log::trace!("LocalCollState in {:?}", s); + match s { + LocalCollState::Ready { key } => { + let name = engine.collection_name(); + let config = self.global_state.config.clone(); + let last_modified = self + .global_state + .collections + .get(name.as_ref()) + .cloned() + .unwrap_or_default(); + return Ok(Some(CollState { + config, + last_modified, + key, + })); + } + LocalCollState::Declined | LocalCollState::NoSuchCollection => return Ok(None), + + _ => { + count += 1; + if count > 10 { + log::warn!("LocalCollStateMachine appears to be looping"); + return Ok(None); + } + // should we have better loop detection? Our limit of 10 + // goes is probably OK for now, but not really ideal. + s = self.advance(s, engine)?; + } + }; + } + } + + pub fn get_state( + engine: &dyn SyncEngine, + global_state: &'state GlobalState, + root_key: &'state KeyBundle, + ) -> error::Result<Option<CollState>> { + let mut gingerbread_man = Self { + global_state, + root_key, + }; + gingerbread_man.run_and_run_as_farst_as_you_can(engine) + } +} + +#[cfg(test)] +mod tests { + use super::super::request::{InfoCollections, InfoConfiguration}; + use super::super::CollectionKeys; + use super::*; + use crate::engine::CollectionRequest; + use crate::engine::{IncomingChangeset, OutgoingChangeset}; + use crate::record_types::{MetaGlobalEngine, MetaGlobalRecord}; + use crate::telemetry; + use anyhow::Result; + use std::cell::{Cell, RefCell}; + use std::collections::HashMap; + use sync_guid::Guid; + + fn get_global_state(root_key: &KeyBundle) -> GlobalState { + let keys = CollectionKeys::new_random() + .unwrap() + .to_encrypted_payload(root_key) + .unwrap(); + GlobalState { + config: InfoConfiguration::default(), + collections: InfoCollections::new(HashMap::new()), + global: MetaGlobalRecord { + sync_id: "syncIDAAAAAA".into(), + storage_version: 5usize, + engines: vec![( + "bookmarks", + MetaGlobalEngine { + version: 1usize, + sync_id: "syncIDBBBBBB".into(), + }, + )] + .into_iter() + .map(|(key, value)| (key.to_owned(), value)) + .collect(), + declined: vec![], + }, + global_timestamp: ServerTimestamp::default(), + keys, + keys_timestamp: ServerTimestamp::default(), + } + } + + struct TestSyncEngine { + collection_name: &'static str, + assoc: Cell<EngineSyncAssociation>, + num_resets: RefCell<usize>, + } + + impl TestSyncEngine { + fn new(collection_name: &'static str, assoc: EngineSyncAssociation) -> Self { + Self { + collection_name, + assoc: Cell::new(assoc), + num_resets: RefCell::new(0), + } + } + fn get_num_resets(&self) -> usize { + *self.num_resets.borrow() + } + } + + impl SyncEngine for TestSyncEngine { + fn collection_name(&self) -> std::borrow::Cow<'static, str> { + self.collection_name.into() + } + + fn apply_incoming( + &self, + _inbound: Vec<IncomingChangeset>, + _telem: &mut telemetry::Engine, + ) -> Result<OutgoingChangeset> { + unreachable!("these tests shouldn't call these"); + } + + fn sync_finished( + &self, + _new_timestamp: ServerTimestamp, + _records_synced: Vec<Guid>, + ) -> Result<()> { + unreachable!("these tests shouldn't call these"); + } + + fn get_collection_requests( + &self, + _server_timestamp: ServerTimestamp, + ) -> Result<Vec<CollectionRequest>> { + unreachable!("these tests shouldn't call these"); + } + + fn get_sync_assoc(&self) -> Result<EngineSyncAssociation> { + Ok(self.assoc.replace(EngineSyncAssociation::Disconnected)) + } + + fn reset(&self, new_assoc: &EngineSyncAssociation) -> Result<()> { + self.assoc.replace(new_assoc.clone()); + *self.num_resets.borrow_mut() += 1; + Ok(()) + } + + fn wipe(&self) -> Result<()> { + unreachable!("these tests shouldn't call these"); + } + } + + #[test] + fn test_unknown() { + let root_key = KeyBundle::new_random().expect("should work"); + let gs = get_global_state(&root_key); + let engine = TestSyncEngine::new("unknown", EngineSyncAssociation::Disconnected); + let cs = LocalCollStateMachine::get_state(&engine, &gs, &root_key).expect("should work"); + assert!(cs.is_none(), "unknown collection name can't sync"); + assert_eq!(engine.get_num_resets(), 0); + } + + #[test] + fn test_known_no_state() { + let root_key = KeyBundle::new_random().expect("should work"); + let gs = get_global_state(&root_key); + let engine = TestSyncEngine::new("bookmarks", EngineSyncAssociation::Disconnected); + let cs = LocalCollStateMachine::get_state(&engine, &gs, &root_key).expect("should work"); + assert!(cs.is_some(), "collection can sync"); + assert_eq!( + engine.assoc.replace(EngineSyncAssociation::Disconnected), + EngineSyncAssociation::Connected(CollSyncIds { + global: "syncIDAAAAAA".into(), + coll: "syncIDBBBBBB".into(), + }) + ); + assert_eq!(engine.get_num_resets(), 1); + } + + #[test] + fn test_known_wrong_state() { + let root_key = KeyBundle::new_random().expect("should work"); + let gs = get_global_state(&root_key); + let engine = TestSyncEngine::new( + "bookmarks", + EngineSyncAssociation::Connected(CollSyncIds { + global: "syncIDXXXXXX".into(), + coll: "syncIDYYYYYY".into(), + }), + ); + let cs = LocalCollStateMachine::get_state(&engine, &gs, &root_key).expect("should work"); + assert!(cs.is_some(), "collection can sync"); + assert_eq!( + engine.assoc.replace(EngineSyncAssociation::Disconnected), + EngineSyncAssociation::Connected(CollSyncIds { + global: "syncIDAAAAAA".into(), + coll: "syncIDBBBBBB".into(), + }) + ); + assert_eq!(engine.get_num_resets(), 1); + } + + #[test] + fn test_known_good_state() { + let root_key = KeyBundle::new_random().expect("should work"); + let gs = get_global_state(&root_key); + let engine = TestSyncEngine::new( + "bookmarks", + EngineSyncAssociation::Connected(CollSyncIds { + global: "syncIDAAAAAA".into(), + coll: "syncIDBBBBBB".into(), + }), + ); + let cs = LocalCollStateMachine::get_state(&engine, &gs, &root_key).expect("should work"); + assert!(cs.is_some(), "collection can sync"); + assert_eq!(engine.get_num_resets(), 0); + } + + #[test] + fn test_declined() { + let root_key = KeyBundle::new_random().expect("should work"); + let mut gs = get_global_state(&root_key); + gs.global.declined.push("bookmarks".to_string()); + let engine = TestSyncEngine::new( + "bookmarks", + EngineSyncAssociation::Connected(CollSyncIds { + global: "syncIDAAAAAA".into(), + coll: "syncIDBBBBBB".into(), + }), + ); + let cs = LocalCollStateMachine::get_state(&engine, &gs, &root_key).expect("should work"); + assert!(cs.is_none(), "declined collection can sync"); + assert_eq!(engine.get_num_resets(), 0); + } +} |