66 lines
1.9 KiB
JavaScript
66 lines
1.9 KiB
JavaScript
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"use strict";
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var rawAsap = require("./raw");
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var freeTasks = [];
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/**
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* Calls a task as soon as possible after returning, in its own event, with
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* priority over IO events. An exception thrown in a task can be handled by
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* `process.on("uncaughtException") or `domain.on("error")`, but will otherwise
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* crash the process. If the error is handled, all subsequent tasks will
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* resume.
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*
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* @param {{call}} task A callable object, typically a function that takes no
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* arguments.
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*/
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module.exports = asap;
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function asap(task) {
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var rawTask;
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if (freeTasks.length) {
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rawTask = freeTasks.pop();
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} else {
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rawTask = new RawTask();
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}
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rawTask.task = task;
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rawTask.domain = process.domain;
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rawAsap(rawTask);
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}
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function RawTask() {
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this.task = null;
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this.domain = null;
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}
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RawTask.prototype.call = function () {
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if (this.domain) {
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this.domain.enter();
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}
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var threw = true;
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try {
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this.task.call();
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threw = false;
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// If the task throws an exception (presumably) Node.js restores the
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// domain stack for the next event.
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if (this.domain) {
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this.domain.exit();
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}
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} finally {
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// We use try/finally and a threw flag to avoid messing up stack traces
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// when we catch and release errors.
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if (threw) {
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// In Node.js, uncaught exceptions are considered fatal errors.
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// Re-throw them to interrupt flushing!
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// Ensure that flushing continues if an uncaught exception is
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// suppressed listening process.on("uncaughtException") or
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// domain.on("error").
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rawAsap.requestFlush();
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}
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// If the task threw an error, we do not want to exit the domain here.
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// Exiting the domain would prevent the domain from catching the error.
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this.task = null;
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this.domain = null;
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freeTasks.push(this);
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}
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};
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