From e760e6bd38eb4d672a4f26c69808cb186fb99991 Mon Sep 17 00:00:00 2001
From: Fabian Seluska <fabianseluska@gmail.com>
Date: Wed, 20 Oct 2021 10:03:48 +0200
Subject: [PATCH] Now has a job queue.

---
 libs/utils/multithread.js | 82 +++++++++++++++++++++------------------
 tests/multihread.test.js  | 30 +++++++-------
 2 files changed, 60 insertions(+), 52 deletions(-)

diff --git a/libs/utils/multithread.js b/libs/utils/multithread.js
index 4c94336..e1a4d5b 100644
--- a/libs/utils/multithread.js
+++ b/libs/utils/multithread.js
@@ -6,71 +6,79 @@ const log = initLog("Worker Setup")
 
 let workerFarm = []
 let workerReady = []
+let scheduledJobs = []
 
-function waitForThread() {
-    return new Promise(
-        (resolve, reject) => {
-            let interval = setInterval(
-                () => {
-                    const readyIndex = workerReady.indexOf(true)
-                    if (readyIndex !== -1) {
-                        clearInterval(interval)
-                        resolve(readyIndex)
-                    }
-                },
-                50
+function scheduler() {
+    if (scheduledJobs.length === 0) return
+
+    const readyIndex = workerReady.indexOf(true)
+    if (readyIndex === -1) return
+
+    workerReady[readyIndex] = false
+    const worker = workerFarm[readyIndex]
+
+    const job = scheduledJobs.shift()
+
+    worker.postMessage({
+        type: 'runScript',
+        script: job.script,
+        data: job.data,
+        id: job.jobID
+    })
+
+    const messageHandler = message => {
+        if (message.id === job.jobID) {
+            workerReady[readyIndex] = true
+            worker.removeListener(
+                'message',
+                messageHandler
             )
+            return job.callback(message.result)
         }
+    }
+
+    worker.on(
+        'message',
+        messageHandler
     )
 }
 
 export function initWorkers(threads) {
     for (let i = 0;  i < threads; ++i) {
         workerFarm.push(new Worker('./libs/utils/multithread/genericWorker.js', { env: SHARE_ENV }))
-    }
 
-    for (const i in workerFarm) {
         const worker = workerFarm[i]
         worker.postMessage({
             type: 'initWorker',
             name: `Worker ${parseInt(i) + 1}`
         })
+
         workerReady[i] = true
     }
 
     log(`Initialised ${threads} workers!`)
+
+    setInterval(
+        scheduler,
+        50
+    )
+
+    log(`Initialised the scheduler!`)
 }
 
 export function spread(script, data) {
     return new Promise(
         async (resolve, reject) => {
-            const readyIndex = await waitForThread()
-            workerReady[readyIndex] = false
-
-            const worker = workerFarm[readyIndex]
             const jobID = randomUUID()
-            worker.postMessage({
-                type: 'runScript',
+
+            scheduledJobs.push({
                 script,
                 data,
-                id: jobID
-            })
-
-            const messageHandler = message => {
-                if (message.id === jobID) {
-                    workerReady[readyIndex] = true
-                    worker.removeListener(
-                        'message',
-                        messageHandler
-                    )
-                    resolve(message.result)
+                jobID,
+                callback: result => {
+                    resolve(result)
                 }
-            }
-
-            worker.on(
-                'message',
-                messageHandler
-            )
+            })
         }
     )
 }
\ No newline at end of file
diff --git a/tests/multihread.test.js b/tests/multihread.test.js
index 0511326..e9b1278 100644
--- a/tests/multihread.test.js
+++ b/tests/multihread.test.js
@@ -5,23 +5,23 @@ import initLog from '../libs/utils/log.js'
 
 const log = initLog("Fib. Test")
 
-initWorkers(10)
+initWorkers(3)
 
-// const jobs = 100
-// let completed = 0
-// for (let i = 0; i < jobs; ++i) {
-//     spread(
-//         './fibonacci.js',
-//         {}
-//     ).then(
-//         result => {
-//             ++completed
-//             log(`Completed job ${completed}/${jobs} -> ${result}`)
+const jobs = 10
+let completed = 0
+for (let i = 0; i < jobs; ++i) {
+    spread(
+        './fibonacci.js',
+        {}
+    ).then(
+        result => {
+            ++completed
+            log(`Completed job ${completed}/${jobs} -> ${result}`)
 
-//             if (completed === jobs) process.exit(0)
-//         }
-//     )
-// }
+            if (completed === jobs) process.exit(0)
+        }
+    )
+}