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Merge pull request #758 from mzgoddard/done-threads-indexof

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Constant time check if a thread is in doneThreads
This commit is contained in:
Ray Schamp 2017-11-07 10:30:15 -05:00 committed by GitHub
commit 5290570fc5
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1 changed files with 26 additions and 9 deletions
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35
src/engine/sequencer.js
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@ -38,7 +38,7 @@ class Sequencer {
let numActiveThreads = Infinity;
// Whether `stepThreads` has run through a full single tick.
let ranFirstTick = false;
const doneThreads = [];
const doneThreads = this.runtime.threads.map(() => null);
// Conditions for continuing to stepping threads:
// 1. We must have threads in the list, and some must be active.
// 2. Time elapsed must be less than WORK_TIME.
@ -54,11 +54,13 @@ class Sequencer {
if (activeThread.stack.length === 0 ||
activeThread.status === Thread.STATUS_DONE) {
// Finished with this thread.
if (doneThreads.indexOf(activeThread) < 0) {
doneThreads.push(activeThread);
}
doneThreads[i] = activeThread;
continue;
}
// A thread was removed, added or this thread was restarted.
if (doneThreads[i] !== null) {
doneThreads[i] = null;
}
if (activeThread.status === Thread.STATUS_YIELD_TICK &&
!ranFirstTick) {
// Clear single-tick yield from the last call of `stepThreads`.
@ -82,12 +84,27 @@ class Sequencer {
ranFirstTick = true;
}
// Filter inactive threads from `this.runtime.threads`.
this.runtime.threads = this.runtime.threads.filter(thread => {
if (doneThreads.indexOf(thread) > -1) {
return false;
numActiveThreads = 0;
for (let i = 0; i < this.runtime.threads.length; i++) {
const thread = this.runtime.threads[i];
if (doneThreads[i] === null) {
this.runtime.threads[numActiveThreads] = thread;
numActiveThreads++;
}
return true;
});
}
this.runtime.threads.length = numActiveThreads;
// Filter undefined and null values from `doneThreads`.
let numDoneThreads = 0;
for (let i = 0; i < doneThreads.length; i++) {
const maybeThread = doneThreads[i];
if (maybeThread !== null) {
doneThreads[numDoneThreads] = maybeThread;
numDoneThreads++;
}
}
doneThreads.length = numDoneThreads;
return doneThreads;
}