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[api-minor] Replace the PromiseCapability with Promise.withResolvers()

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This replaces our custom `PromiseCapability`-class with the new native `Promise.withResolvers()` functionality, which does *almost* the same thing[1]; please see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/withResolvers

The only difference is that `PromiseCapability` also had a `settled`-getter, which was however not widely used and the call-sites can either be removed or re-factored to avoid it. In particular:
 - In `src/display/api.js` we can tweak the `PDFObjects`-class to use a "special" initial data-value and just compare against that, in order to replace the `settled`-state.
 - In `web/app.js` we change the only case to manually track the `settled`-state, which should hopefully be OK given how this is being used.
 - In `web/pdf_outline_viewer.js` we can remove the `settled`-checks, since the code should work just fine without it. The only thing that could potentially happen is that we try to `resolve` a Promise multiple times, which is however *not* a problem since the value of a Promise cannot be changed once fulfilled or rejected.
 - In `web/pdf_viewer.js` we can remove the `settled`-checks, since the code should work fine without them:
     - For the `_onePageRenderedCapability` case the `settled`-check is used in a `EventBus`-listener which is *removed* on its first (valid) invocation.
     - For the `_pagesCapability` case the `settled`-check is used in a print-related helper that works just fine with "only" the other checks.
 - In `test/unit/api_spec.js` we can change the few relevant cases to manually track the `settled`-state, since this is both simple and *test-only* code.

---
[1] In browsers/environments that lack native support, note [the compatibility data](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/withResolvers#browser_compatibility), it'll be polyfilled via the `core-js` library (but only in `legacy` builds).
This commit is contained in:
Jonas Jenwald 2024-03-28 16:42:37 +01:00
parent 55db43966e
commit e4d0e84802
28 changed files with 159 additions and 252 deletions
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8
web/pdf_scripting_manager.js
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@ -16,7 +16,7 @@
/** @typedef {import("./event_utils").EventBus} EventBus */
import { apiPageLayoutToViewerModes, RenderingStates } from "./ui_utils.js";
import { PromiseCapability, shadow } from "pdfjs-lib";
import { shadow } from "pdfjs-lib";
/**
* @typedef {Object} PDFScriptingManagerOptions
@ -199,7 +199,7 @@ class PDFScriptingManager {
return;
}
await this.#willPrintCapability?.promise;
this.#willPrintCapability = new PromiseCapability();
this.#willPrintCapability = Promise.withResolvers();
try {
await this.#scripting.dispatchEventInSandbox({
id: "doc",
@ -344,7 +344,7 @@ class PDFScriptingManager {
visitedPages = this._visitedPages;
if (initialize) {
this.#closeCapability = new PromiseCapability();
this.#closeCapability = Promise.withResolvers();
}
if (!this.#closeCapability) {
return; // Scripting isn't fully initialized yet.
@ -406,7 +406,7 @@ class PDFScriptingManager {
}
#initScripting() {
this.#destroyCapability = new PromiseCapability();
this.#destroyCapability = Promise.withResolvers();
if (this.#scripting) {
throw new Error("#initScripting: Scripting already exists.");