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3374e90 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 | //! JS Pool — the main interface for the host engine.
//!
//! JsPool manages a pool of worker threads, each running a QuickJS runtime.
//! It routes JS evaluation requests to workers with plugin affinity.
//! The pool grows on demand up to `max_workers` when all worker queues are full.
use crate::config::JsPoolConfig;
use crate::error::JsError;
use crate::worker::{JsResult, JsTask, JsTaskKind, JsWorker};
use crossbeam_channel::{self, Sender};
use parking_lot::Mutex;
use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
use std::sync::Arc;
/// The JS pool — the main interface for the host engine.
pub struct JsPool {
workers: Mutex<Vec<std::thread::JoinHandle<()>>>,
task_senders: Mutex<Vec<Sender<JsTask>>>,
/// Lock-free worker count for fast affinity selection.
worker_count: AtomicUsize,
shutdown: Arc<AtomicBool>,
config: JsPoolConfig,
}
impl JsPool {
/// Create a new JS pool with the given configuration.
pub fn new(config: JsPoolConfig) -> Result<Self, JsError> {
let num_workers = config.initial_workers;
let shutdown = Arc::new(AtomicBool::new(false));
let mut workers = Vec::with_capacity(num_workers);
let mut task_senders = Vec::with_capacity(num_workers);
for id in 0..num_workers {
let (tx, rx) = crossbeam_channel::bounded::<JsTask>(256);
let handle = JsWorker::spawn(id, config.clone(), rx, shutdown.clone());
workers.push(handle);
task_senders.push(tx);
}
Ok(Self {
workers: Mutex::new(workers),
task_senders: Mutex::new(task_senders),
worker_count: AtomicUsize::new(num_workers),
shutdown,
config,
})
}
/// Evaluate a JavaScript string and return the result as JSON.
/// Uses simple one-shot evaluation with default timeout.
/// `input` is injected as the global variable `input` before eval.
pub fn eval_js(&self, plugin_id: &str, code: &str, input: &str) -> Result<String, JsError> {
self.eval_js_opts(
plugin_id,
code,
input,
None,
self.config.default_timeout_ms,
)
}
/// Evaluate JavaScript with options.
pub fn eval_js_opts(
&self,
plugin_id: &str,
code: &str,
input: &str,
filename: Option<String>,
timeout_ms: u32,
) -> Result<String, JsError> {
if self.shutdown.load(Ordering::Acquire) {
return Err(JsError::PoolShutdown);
}
let (reply_tx, reply_rx) = crossbeam_channel::bounded::<JsResult>(1);
let task = JsTask {
plugin_id: plugin_id.to_string(),
kind: JsTaskKind::Eval {
code: code.to_string(),
input: input.to_string(),
filename,
timeout_ms,
},
reply: reply_tx,
};
self.dispatch_task(plugin_id, task)?;
match reply_rx.recv_timeout(std::time::Duration::from_millis(
(timeout_ms as u64).max(self.config.default_timeout_ms as u64) + 2000,
)) {
Ok(result) => result.result,
Err(_) => Err(JsError::Timeout(timeout_ms)),
}
}
/// Call a named JavaScript function.
/// `fn_source` is evaluated on first call (or if the source hash changes).
/// `args_json` is passed as a single string argument (no eval of user data).
pub fn call_js_fn(
&self,
plugin_id: &str,
name: &str,
fn_source: &str,
args_json: &str,
) -> Result<String, JsError> {
if self.shutdown.load(Ordering::Acquire) {
return Err(JsError::PoolShutdown);
}
let (reply_tx, reply_rx) = crossbeam_channel::bounded::<JsResult>(1);
let task = JsTask {
plugin_id: plugin_id.to_string(),
kind: JsTaskKind::CallFn {
name: name.to_string(),
fn_source: fn_source.to_string(),
args_json: args_json.to_string(),
timeout_ms: self.config.default_timeout_ms,
},
reply: reply_tx,
};
self.dispatch_task(plugin_id, task)?;
match reply_rx.recv_timeout(std::time::Duration::from_millis(
self.config.default_timeout_ms as u64 + 2000,
)) {
Ok(result) => result.result,
Err(_) => Err(JsError::Timeout(self.config.default_timeout_ms)),
}
}
/// Clear a named JS function from a plugin's context.
pub fn clear_js_fn(&self, plugin_id: &str, name: &str) -> Result<u8, JsError> {
if self.shutdown.load(Ordering::Acquire) {
return Err(JsError::PoolShutdown);
}
let (reply_tx, reply_rx) = crossbeam_channel::bounded::<JsResult>(1);
let task = JsTask {
plugin_id: plugin_id.to_string(),
kind: JsTaskKind::ClearFn {
name: name.to_string(),
},
reply: reply_tx,
};
self.dispatch_task(plugin_id, task)?;
match reply_rx.recv_timeout(std::time::Duration::from_millis(
self.config.default_timeout_ms as u64 + 2000,
)) {
Ok(result) => result.result.map(|_| 0),
Err(_) => Err(JsError::Timeout(self.config.default_timeout_ms)),
}
}
/// Evict a plugin's JS context (called on plugin uninstall).
pub fn evict_plugin(&self, plugin_id: &str) {
if self.shutdown.load(Ordering::Acquire) {
return;
}
// Send evict to all workers since we don't know which one has the context
let senders = self.task_senders.lock();
for tx in senders.iter() {
let (reply_tx, reply_rx) = crossbeam_channel::bounded::<JsResult>(1);
let task = JsTask {
plugin_id: plugin_id.to_string(),
kind: JsTaskKind::Evict,
reply: reply_tx,
};
let _ = tx.send(task);
let _ = reply_rx.recv_timeout(std::time::Duration::from_secs(2));
}
}
/// Dispatch a task to a worker with plugin affinity.
///
/// Strategy:
/// 1. Try the affinity worker first (hash-based).
/// 2. If full, try any other worker with capacity (overflow routing).
/// 3. If all full and pool < max_workers, grow the pool and retry.
/// 4. If still can't dispatch, return PoolBusy.
fn dispatch_task(&self, plugin_id: &str, mut task: JsTask) -> Result<(), JsError> {
if self.shutdown.load(Ordering::Acquire) {
return Err(JsError::PoolShutdown);
}
// Step 1: Try affinity worker first
let affinity_idx = self.select_worker(plugin_id);
{
let senders = self.task_senders.lock();
if let Some(tx) = senders.get(affinity_idx) {
match tx.try_send(task) {
Ok(()) => return Ok(()),
Err(crossbeam_channel::TrySendError::Disconnected(_)) => {
return Err(JsError::PoolShutdown);
}
Err(crossbeam_channel::TrySendError::Full(t)) => {
// Recover the task for overflow routing
task = t;
}
}
}
}
// Step 2: Overflow routing — try any other worker with capacity
{
let senders = self.task_senders.lock();
let count = senders.len();
for i in 0..count {
if i == affinity_idx {
continue;
}
if let Some(tx) = senders.get(i) {
match tx.try_send(task) {
Ok(()) => return Ok(()),
Err(crossbeam_channel::TrySendError::Disconnected(_)) => {
return Err(JsError::PoolShutdown);
}
Err(crossbeam_channel::TrySendError::Full(t)) => {
task = t;
continue;
}
}
}
}
}
// Step 3: All full — try to grow the pool if under max_workers
if self.maybe_grow() {
// The newly added worker is at the end — try it first since it's
// guaranteed to have an empty queue
let senders = self.task_senders.lock();
if let Some(tx) = senders.last() {
match tx.try_send(task) {
Ok(()) => return Ok(()),
Err(crossbeam_channel::TrySendError::Disconnected(_)) => {
return Err(JsError::PoolShutdown);
}
Err(crossbeam_channel::TrySendError::Full(_)) => {
// Extremely unlikely but possible under heavy contention
}
}
}
}
// Step 4: Still can't dispatch
Err(JsError::PoolBusy)
}
/// Select a worker for a given plugin_id.
/// Uses hash-based affinity so the same plugin always goes to the same worker.
fn select_worker(&self, plugin_id: &str) -> usize {
let hash = simple_hash(plugin_id);
let count = self.worker_count.load(Ordering::Acquire);
if count == 0 {
0
} else {
(hash as usize) % count
}
}
/// Try to spawn additional workers if the pool is under max_workers.
/// Returns `true` if at least one new worker was added.
fn maybe_grow(&self) -> bool {
let current = self.worker_count.load(Ordering::Acquire);
if current >= self.config.max_workers {
return false;
}
// Double-check under lock to avoid over-spawning
let mut senders = self.task_senders.lock();
let mut workers = self.workers.lock();
let count = senders.len();
if count >= self.config.max_workers {
return false;
}
let new_id = count;
let (tx, rx) = crossbeam_channel::bounded::<JsTask>(256);
let handle = JsWorker::spawn(new_id, self.config.clone(), rx, self.shutdown.clone());
workers.push(handle);
senders.push(tx);
// Update lock-free counter after the worker is registered
self.worker_count.store(count + 1, Ordering::Release);
tracing::info!(
old_count = count,
new_count = count + 1,
max = self.config.max_workers,
"JS pool grew — added worker"
);
true
}
}
impl Drop for JsPool {
fn drop(&mut self) {
// SeqCst ensures all other threads see shutdown=true BEFORE we clear senders
self.shutdown.store(true, Ordering::SeqCst);
// Fence: nothing before this point reorders after
std::sync::atomic::fence(Ordering::SeqCst);
// Drop senders to signal workers to stop
self.task_senders.lock().clear();
// Join all worker threads
let mut workers = self.workers.lock();
for handle in workers.drain(..) {
let _ = handle.join();
}
}
}
/// Simple FNV-1a hash for plugin_id -> worker affinity.
pub fn simple_hash(s: &str) -> u64 {
let mut hash: u64 = 0xcbf29ce484222325;
for byte in s.bytes() {
hash ^= byte as u64;
hash = hash.wrapping_mul(0x100000001b3);
}
hash
}
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