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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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11
src/display/node_stream.js
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@ -18,7 +18,6 @@ import {
assert,
isNodeJS,
MissingPDFException,
PromiseCapability,
} from "../shared/util.js";
import {
extractFilenameFromHeader,
@ -128,8 +127,8 @@ class BaseFullReader {
this._isRangeSupported = !source.disableRange;
this._readableStream = null;
this._readCapability = new PromiseCapability();
this._headersCapability = new PromiseCapability();
this._readCapability = Promise.withResolvers();
this._headersCapability = Promise.withResolvers();
}
get headersReady() {
@ -163,7 +162,7 @@ class BaseFullReader {
const chunk = this._readableStream.read();
if (chunk === null) {
this._readCapability = new PromiseCapability();
this._readCapability = Promise.withResolvers();
return this.read();
}
this._loaded += chunk.length;
@ -230,7 +229,7 @@ class BaseRangeReader {
this.onProgress = null;
this._loaded = 0;
this._readableStream = null;
this._readCapability = new PromiseCapability();
this._readCapability = Promise.withResolvers();
const source = stream.source;
this._isStreamingSupported = !source.disableStream;
}
@ -250,7 +249,7 @@ class BaseRangeReader {
const chunk = this._readableStream.read();
if (chunk === null) {
this._readCapability = new PromiseCapability();
this._readCapability = Promise.withResolvers();
return this.read();
}
this._loaded += chunk.length;