Make history-related constants configurable

src/app.rs

@@ -39,7 +39,7 @@ use crate::{
 };
 
 pub struct App {
-  pub config: Config,
+  pub config: Arc<Config>,
   pub clients: NonEmpty<matrix_sdk::Client>,
   pub commands: RataCommands,
   pub tick_rate: f64,
@@ -120,6 +120,7 @@ impl App {
     }
     let clients = NonEmpty::collect(clients).expect("map on NonEmpty returned empty vec");
 
+    let config = Arc::new(config);
     let home = Home::new(config.clone());
     let fps = FpsCounter::default();
     let mode = Mode::Home;
@@ -398,7 +399,7 @@ impl App {
   ) {
     futures::future::join_all(
       rooms
-        .map(|(client, room)| RoomBuffer::new(client, room))
+        .map(|(client, room)| RoomBuffer::new(self.config.clone(), client, room))
         .map(|fut| fut.map(|res| res.expect("Failed to create RoomBuffer at startup"))),
     )
     .await

src/buffers/room.rs

@@ -47,6 +47,7 @@ use sorted_vec::SortedVec;
 use tokio::sync::oneshot;
 
 use super::{Buffer, BufferId, BufferItem, BufferItemContent, BufferSortKey, FullyReadStatus};
+use crate::config::Config;
 use crate::widgets::Prerender;
 
 /// Like [`BufferItemContent`] but owned.
@@ -368,6 +369,8 @@ impl SingleClientRoomBuffer {
 }
 
 pub struct RoomBuffer {
+  config: Arc<Config>,
+
   room_id: OwnedRoomId,
 
   computed_roominfo: Option<ComputedRoomInfo>,
@@ -400,8 +403,13 @@ impl DynamicUsage for RoomBuffer {
 }
 
 impl RoomBuffer {
-  pub async fn new(initial_client: Client, room_id: OwnedRoomId) -> Result<Self> {
+  pub async fn new(
+    config: Arc<Config>,
+    initial_client: Client,
+    room_id: OwnedRoomId,
+  ) -> Result<Self> {
     let mut self_ = RoomBuffer {
+      config,
       room_id,
       computed_roominfo: None,
       update_roominfo_rx: None,
@@ -674,8 +682,12 @@ impl Buffer for RoomBuffer {
             // * we already backfilled a lot so we don't exhaust the available memory
             // * we already reached an unread message, in which case it's pointless to
             //   backfill as we already know there are unread messages.
-            if buf.items.len() < 1000 {
+            if buf.items.len() < self.config.history.max_prefetch_unread
-              buf.back_pagination_request.fetch_max(50, Ordering::Relaxed);
+              && self.config.history.prefetch_unread > 0
+            {
+              buf
+                .back_pagination_request
+                .fetch_max(self.config.history.prefetch_unread, Ordering::Relaxed);
             }
           }
         }

src/components/backlog.rs

@@ -15,6 +15,7 @@
  */
 
 use std::ops::DerefMut;
+use std::sync::Arc;
 
 use color_eyre::eyre::{Result, WrapErr};
 use crossterm::event::{KeyCode, KeyEvent, KeyEventKind, KeyModifiers};
@@ -41,7 +42,7 @@ struct ScrollPosition {
 
 #[derive(Debug)]
 pub struct Backlog {
-  config: Config,
+  config: Arc<Config>,
   /// Used to compute scroll on PageUp/PageDown when configured to a percentage.
   last_height: u16,
   scroll_position: Option<ScrollPosition>,
@@ -97,8 +98,10 @@ impl Component for Backlog {
 
     // We are reaching the end of the backlog we have locally, ask the buffer to fetch
     // more if it can
-    if undrawn_widgets_at_top <= 100 {
+    if undrawn_widgets_at_top <= self.config.history.min_prefetch
-      active_buffer.request_back_pagination(200);
+      && self.config.history.prefetch > 0
+    {
+      active_buffer.request_back_pagination(self.config.history.prefetch);
     }
 
     Ok(())
@@ -106,7 +109,7 @@ impl Component for Backlog {
 }
 
 impl Backlog {
-  pub fn new(config: Config) -> Self {
+  pub fn new(config: Arc<Config>) -> Self {
     Backlog {
       config,
       last_height: 30, // Arbitrary default, only useful when user scrolls before first render

src/components/buflist.rs

@@ -14,6 +14,8 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+use std::sync::Arc;
+
 use color_eyre::eyre::{Result, WrapErr};
 use crossterm::event::{MouseEvent, MouseEventKind};
 use ratatui::{prelude::*, widgets::*};
@@ -29,14 +31,14 @@ use crate::{
 
 pub struct Buflist {
   command_tx: Option<UnboundedSender<Action>>,
-  config: Config,
+  config: Arc<Config>,
 
   /// Updated by [`draw`], used by [`handle_mouse_events`] to find which buffer was clicked.
   last_area: Option<Rect>,
   last_num_buffers: Option<usize>,
 }
 impl Buflist {
-  pub fn new(config: Config) -> Self {
+  pub fn new(config: Arc<Config>) -> Self {
     Buflist {
       command_tx: None,
       config,

src/components/home.rs

@@ -14,6 +14,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+use std::sync::Arc;
 use std::{collections::HashMap, time::Duration};
 
 use color_eyre::eyre::{Result, WrapErr};
@@ -32,14 +33,14 @@ use crate::{
 
 pub struct Home {
   command_tx: Option<UnboundedSender<Action>>,
-  config: Config,
+  config: Arc<Config>,
   buflist: Buflist,
   backlog: Backlog,
   textarea: TextArea<'static>,
 }
 
 impl Home {
-  pub fn new(config: Config) -> Self {
+  pub fn new(config: Arc<Config>) -> Self {
     let mut self_ = Home {
       command_tx: None,
       buflist: Buflist::new(config.clone()),

src/config.rs

@@ -102,6 +102,14 @@ impl<'de> Visitor<'de> for ScrollAmountVisitor {
   }
 }
 
+#[derive(Clone, Debug, Deserialize)]
+pub struct HistoryConfig {
+  pub prefetch_unread: u16,
+  pub max_prefetch_unread: usize,
+  pub min_prefetch: usize,
+  pub prefetch: u16,
+}
+
 #[derive(Clone, Debug, Deserialize)]
 pub struct MouseConfig {
   pub enable: bool,
@@ -149,6 +157,7 @@ pub struct Config {
   #[serde(default, flatten)]
   pub config: AppConfig,
   pub accounts: nonempty::NonEmpty<AccountConfig>,
+  pub history: HistoryConfig,
   #[serde(default)]
   pub keybindings: KeyBindings,
   pub keyboard: KeyboardConfig,

src/default_config.toml

@@ -14,6 +14,23 @@ scroll_page = "50%"
 [mouse]
 enable = true
 
+[history]
+# When there are unread events in a room, how many past events should be fetched
+# at once to check whether there are unread messages (as opposed to non-message
+# events), to find if the room should colored with style.buflist.unread_message or
+# style.buflist.unread_event
+prefetch_unread = 50
+# When do stop iteratively fetching pages of size $prefetch_unread when no unread
+# messages are found
+max_prefetch_unread = 1000
+
+# How many older events to keep above the screen in case the user hits PageUp later.
+# Set to 0 to only fetch when the user reaches an unfetched message.
+min_prefetch = 100
+# When getting close to the oldest event we know about, how many events should be
+# fetched at once
+prefetch = 200
+
 # Configuration for the list of rooms on the right.
 [layout.buflist]
 # How long room names can be before being truncated.

tests/components/backlog.rs

@@ -14,6 +14,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+use std::sync::Arc;
 use std::path::PathBuf;
 
 use color_eyre::eyre::WrapErr;
@@ -29,7 +30,7 @@ fn config() -> Config {
   std::env::set_var("RATATRIX_CONFIG", PathBuf::from(".config/"));
   let c = Config::new();
   std::env::remove_var("RATATRIX_CONFIG");
-  c.unwrap()
+  Arc::new(c.unwrap())
 }
 
 fn rect(x: u16, y: u16, width: u16, height: u16) -> Rect {