From df36cf3099f6010c4fc62109b85d4d1e62f160cc Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Thu, 9 Nov 2023 16:32:31 +0100
Subject: layout: add helpers to LayoutHistory and prepare integration with
 Table

---
 src/rpc/layout/history.rs | 41 +++++++++++++++++++++++++++++++++--------
 src/rpc/layout/manager.rs | 33 ++++++++++++++++++++++++++++++++-
 src/rpc/layout/schema.rs  |  9 ++++++---
 src/rpc/layout/version.rs |  2 +-
 src/table/table.rs        |  2 ++
 5 files changed, 74 insertions(+), 13 deletions(-)

diff --git a/src/rpc/layout/history.rs b/src/rpc/layout/history.rs
index e17a1c77..dbb02269 100644
--- a/src/rpc/layout/history.rs
+++ b/src/rpc/layout/history.rs
@@ -32,14 +32,6 @@ impl LayoutHistory {
 		self.versions.last().as_ref().unwrap()
 	}
 
-	pub fn all_storage_nodes(&self) -> HashSet<Uuid> {
-		self.versions
-			.iter()
-			.map(|x| x.nongateway_nodes())
-			.flatten()
-			.collect::<HashSet<_>>()
-	}
-
 	pub fn update_hashes(&mut self) {
 		self.trackers_hash = self.calculate_trackers_hash();
 		self.staging_hash = self.calculate_staging_hash();
@@ -53,6 +45,39 @@ impl LayoutHistory {
 		blake2sum(&nonversioned_encode(&self.staging).unwrap()[..])
 	}
 
+	// ------------------ who stores what now? ---------------
+
+	pub fn max_ack(&self) -> u64 {
+		self.calculate_global_min(&self.update_trackers.ack_map)
+	}
+
+	pub fn all_storage_nodes(&self) -> HashSet<Uuid> {
+		// TODO: cache this
+		self.versions
+			.iter()
+			.map(|x| x.nongateway_nodes())
+			.flatten()
+			.collect::<HashSet<_>>()
+	}
+
+	pub fn read_nodes_of(&self, position: &Hash) -> Vec<Uuid> {
+		let sync_min = self.calculate_global_min(&self.update_trackers.sync_map);
+		let version = self
+			.versions
+			.iter()
+			.find(|x| x.version == sync_min)
+			.or(self.versions.last())
+			.unwrap();
+		version.nodes_of(position, version.replication_factor)
+	}
+
+	pub fn write_sets_of(&self, position: &Hash) -> Vec<Vec<Uuid>> {
+		self.versions
+			.iter()
+			.map(|x| x.nodes_of(position, x.replication_factor))
+			.collect::<Vec<_>>()
+	}
+
 	// ------------------ update tracking ---------------
 
 	pub(crate) fn update_trackers(&mut self, node_id: Uuid) {
diff --git a/src/rpc/layout/manager.rs b/src/rpc/layout/manager.rs
index c1417dac..b0302b12 100644
--- a/src/rpc/layout/manager.rs
+++ b/src/rpc/layout/manager.rs
@@ -1,4 +1,5 @@
-use std::sync::{Arc, RwLock, RwLockReadGuard};
+use std::collections::HashMap;
+use std::sync::{Arc, Mutex, RwLock, RwLockReadGuard};
 use std::time::Duration;
 
 use serde::{Deserialize, Serialize};
@@ -26,6 +27,8 @@ pub struct LayoutManager {
 	layout: Arc<RwLock<LayoutHistory>>,
 	pub(crate) change_notify: Arc<Notify>,
 
+	table_sync_version: Mutex<HashMap<String, u64>>,
+
 	pub(crate) rpc_helper: RpcHelper,
 	system_endpoint: Arc<Endpoint<SystemRpc, System>>,
 }
@@ -117,6 +120,34 @@ impl LayoutManager {
 		Ok(())
 	}
 
+	pub fn add_table(&self, table_name: &'static str) {
+		let first_version = self.layout().versions.first().unwrap().version;
+
+		self.table_sync_version
+			.lock()
+			.unwrap()
+			.insert(table_name.to_string(), first_version);
+	}
+
+	pub fn sync_table_until(self: &Arc<Self>, table_name: &'static str, version: u64) {
+		let mut table_sync_version = self.table_sync_version.lock().unwrap();
+		*table_sync_version.get_mut(table_name).unwrap() = version;
+		let sync_until = table_sync_version.iter().map(|(_, v)| *v).max().unwrap();
+		drop(table_sync_version);
+
+		let mut layout = self.layout.write().unwrap();
+		if layout
+			.update_trackers
+			.sync_map
+			.set_max(self.node_id, sync_until)
+		{
+			layout.update_hashes();
+			self.broadcast_update(SystemRpc::AdvertiseClusterLayoutTrackers(
+				layout.update_trackers.clone(),
+			));
+		}
+	}
+
 	// ---- INTERNALS ---
 
 	fn merge_layout(&self, adv: &LayoutHistory) -> Option<LayoutHistory> {
diff --git a/src/rpc/layout/schema.rs b/src/rpc/layout/schema.rs
index db60c806..89f5c361 100644
--- a/src/rpc/layout/schema.rs
+++ b/src/rpc/layout/schema.rs
@@ -375,14 +375,17 @@ impl UpdateTracker {
 		changed
 	}
 
-	pub(crate) fn set_max(&mut self, peer: Uuid, value: u64) {
+	pub(crate) fn set_max(&mut self, peer: Uuid, value: u64) -> bool {
 		match self.0.get_mut(&peer) {
-			Some(e) => {
-				*e = std::cmp::max(*e, value);
+			Some(e) if *e < value => {
+				*e = value;
+				true
 			}
 			None => {
 				self.0.insert(peer, value);
+				true
 			}
+			_ => false,
 		}
 	}
 }
diff --git a/src/rpc/layout/version.rs b/src/rpc/layout/version.rs
index 65c62f63..8133672a 100644
--- a/src/rpc/layout/version.rs
+++ b/src/rpc/layout/version.rs
@@ -109,7 +109,7 @@ impl LayoutVersion {
 			.collect::<Vec<_>>()
 	}
 
-	/// Walk the ring to find the n servers in which data should be replicated
+	/// Return the n servers in which data for this hash should be replicated
 	pub fn nodes_of(&self, position: &Hash, n: usize) -> Vec<Uuid> {
 		assert_eq!(n, self.replication_factor);
 
diff --git a/src/table/table.rs b/src/table/table.rs
index 3e3fd138..997fd7dc 100644
--- a/src/table/table.rs
+++ b/src/table/table.rs
@@ -80,6 +80,8 @@ impl<F: TableSchema, R: TableReplication> Table<F, R> {
 		let syncer = TableSyncer::new(system.clone(), data.clone(), merkle_updater.clone());
 		let gc = TableGc::new(system.clone(), data.clone());
 
+		system.layout_manager.add_table(F::TABLE_NAME);
+
 		let table = Arc::new(Self {
 			system,
 			data,
-- 
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