Add an option to change the size of the pool of candidates

This can be changed through the CLI args or in the config file.

CHANGELOG.md

@@ -5,17 +5,23 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
-### Fixed
-- If the setting `screen.lines` is present in the TOML config file, apply it only on inline mode
-- Respect `screen.lines` option from config file when no `--lines` argument is given
-- Ensure `-v` flag is in lowercase in CLI help message
+### Added
+- New argument, `--pool`, and config option `advanced.pool_size` (or `advanced.pool`).
+  This option can change the size of the pool of candidates that are kept in memory.
+  Increasing this number might result in the program using too much memory.
+  This is an advanced feature and should be used with care.
 
 ### Changed
 - Bump `unicode-segmentation` 1.9.0 to 1.10.0
 - Bump `futures` from 0.3.21 to 0.3.25
 - Bump `env_logger` from 0.9.0 to 0.10.0
 - Bump `libc` from 0.2.129 to 0.2.139
 
+### Fixed
+- If the setting `screen.lines` is present in the TOML config file, apply it only on inline mode
+- Respect `screen.lines` option from config file when no `--lines` argument is given
+- Ensure `-v` flag is in lowercase in CLI help message
+
 ## [v2.6.0] 2022-01-23
 ### Changed
 - Update to edition 2021 and set rust-version to 1.58

src/config.rs

@@ -25,6 +25,7 @@ pub struct Args {
     pub lines: Option<usize>,
     pub config: Option<String>,
     pub search: Option<String>,
+    pub pool: Option<usize>,
 }
 
 /// Arc version of Cfg
@@ -46,6 +47,9 @@ pub struct Cfg {
     pub candidate: CandidateConfig,
     #[serde(default)]
     pub selection: SelectionConfig,
+
+    #[serde(default)]
+    pub advanced: AdvancedConfig,
 }
 
 /// Configuration constructor
@@ -125,6 +129,10 @@ impl Configurator {
                 config.initial_query = Some(q);
             }
 
+            if let Some(pool) = args.pool {
+                config.advanced.set_pool_size(pool);
+            }
+
             self.config = Some(config);
         }
 

src/config/components.rs

@@ -7,6 +7,8 @@ const DEFAULT_HEIGHT: usize = 6;
 const MIN_HEIGHT: usize = 3;
 const MIN_WIDTH: usize = 4;
 
+const DEFAULT_POOL_SIZE: usize = 50000;
+
 #[derive(Deserialize, Clone, Debug, PartialEq)]
 enum Mode {
     #[serde(rename = "full")]
@@ -91,6 +93,23 @@ impl ScreenConfig {
     }
 }
 
+/// Main advanced set of configuration options
+#[derive(Deserialize, Clone, Debug, Default)]
+pub struct AdvancedConfig {
+    #[serde(default, alias = "pool")]
+    pool_size: Option<usize>,
+}
+
+impl AdvancedConfig {
+    pub fn pool_size(&self) -> usize {
+        self.pool_size.unwrap_or(DEFAULT_POOL_SIZE)
+    }
+
+    pub fn set_pool_size(&mut self, pool_size: usize) {
+        self.pool_size = Some(pool_size)
+    }
+}
+
 /// Prompt UI component configuration options
 ///
 /// The prompt is where you write the search query

src/engine.rs

@@ -4,19 +4,24 @@
 //! Once a search is done all the results will be sent to the screen.
 
 use crate::common::{Result, Text, TextBuilder};
+use crate::config::Config;
 use crate::events::Event;
 use crate::fuzzy;
 use async_std::channel::{Receiver, Sender};
 use async_std::prelude::*;
 use std::collections::VecDeque;
 
 const BUFFER_LIMIT: usize = 5000;
-const POOL_LIMIT: usize = 50000;
 
 /// Run the search engine task
-pub async fn task(mut input_recv: Receiver<Event>, output_sender: Sender<Event>) -> Result<()> {
+pub async fn task(
+    config: Config,
+    mut input_recv: Receiver<Event>,
+    output_sender: Sender<Event>,
+) -> Result<()> {
     log::trace!("starting search engine");
 
+    let pool_size = config.advanced.pool_size();
     let mut pool: VecDeque<Text> = VecDeque::new();
     let mut count = 0;
     let mut query = String::from("");
@@ -32,11 +37,8 @@ pub async fn task(mut input_recv: Receiver<Event>, output_sender: Sender<Event>)
 
                 // The pool might be full (too many lines in memory)
                 // so we drop the first line
-                if pool.len() > POOL_LIMIT {
-                    log::trace!(
-                        "pool limit ({:?}) exceeded, dropping first line",
-                        POOL_LIMIT
-                    );
+                if pool.len() > pool_size {
+                    log::trace!("pool limit ({:?}) exceeded, dropping first line", pool_size);
                     let _f = pool.pop_front();
                 }
 

src/main.rs

@@ -28,6 +28,9 @@ OPTIONS:
     -c, --config <FILE>     Uses a custom config file
     -l, --lines <LINES>     Number of lines to display in inline mode, including prompt
     -s, --search <QUERY>    Start searching with the given query
+    -p, --pool <SIZE>       Advanced: size of the pool of candidates to keep in memory.
+                            Default is 50000. Note that increasing this number might
+                            result in the program using too much memory
 
 SUPPORTED KEYS:
     - Enter to select the current highlighted match and print it to STDOUT
@@ -158,6 +161,7 @@ fn parse_args() -> std::result::Result<Args, pico_args::Error> {
         search,
         lines: pargs.opt_value_from_str(["-l", "--lines"])?,
         config: pargs.opt_value_from_str(["-c", "--config"])?,
+        pool: pargs.opt_value_from_str(["-p", "--pool"])?,
     };
 
     let remaining = pargs.finish();

src/supervisor.rs

@@ -56,12 +56,12 @@ where
 
     let screen_task = task::spawn(screen::task(config.clone(), outbox, output_recv));
     let person_task = task::spawn(person_input::task(
-        config,
+        config.clone(),
         inbox,
         input_sender.clone(),
         output_sender.clone(),
     ));
-    let engine_task = task::spawn(engine::task(input_recv, output_sender));
+    let engine_task = task::spawn(engine::task(config, input_recv, output_sender));
     let data_task = task::spawn(data_input::task(stdin, input_sender));
 
     let selection = screen_task.await;