pdf.js.mirror/web/pdf_text_extractor.js
Jonas Jenwald c70ff5a7c0 Improve and simplify the PdfTextExtractor implementation
Working on PR 20784, I couldn't help noticing that this code can be improved a little bit.

 - Only initialize `PdfTextExtractor` in development mode and MOZCENTRAL builds, since it's unused elsewhere.

 - Re-factor how `PdfTextExtractor` waits for the viewer to be available/ready, by using existing (internal) events.
   This simplifies the `PdfTextExtractor` class and removes its `setViewer` method, which improves general consistency since normally the viewer-components don't use such a method in that way (here it was effectively used as a stand-in for a `setDocument` method).

 - Finally, while slightly unrelated, rename the `#getAllTextInProgress` field in the `PDFViewer` class to `#copyAllInProgress` to clearly indicate what it's for since the `getAllText` method is used more generally now.
2026-03-03 15:51:08 +01:00

77 lines
2.1 KiB
JavaScript

/* Copyright 2024 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* This class manages the interaction of extracting the text content of the page
* and passing it back to the external service.
*/
class PdfTextExtractor {
/** @type {BaseExternalServices} */
#externalServices;
/** @type {?Promise<string>} */
#textPromise;
#capability = Promise.withResolvers();
constructor(externalServices, pdfViewer, eventBus) {
this.#externalServices = externalServices;
eventBus._on("pagesinit", () => {
this.#capability.resolve(pdfViewer);
});
eventBus._on("pagesdestroy", () => {
this.#capability.reject(new Error("pagesdestroy"));
this.#textPromise = null;
this.#capability = Promise.withResolvers();
});
window.addEventListener("requestTextContent", ({ detail }) => {
this.extractTextContent(detail.requestId);
});
}
/**
* Builds up all of the text from a PDF.
*
* @param {number} requestId
*/
async extractTextContent(requestId) {
if (!this.#textPromise) {
const textPromise = (this.#textPromise = this.#capability.promise.then(
pdfViewer => pdfViewer.getAllText()
));
// After the text resolves, cache the text for a little bit in case
// multiple consumers call it.
textPromise.then(() => {
setTimeout(() => {
if (this.#textPromise === textPromise) {
this.#textPromise = null;
}
}, 5000);
});
}
this.#externalServices.reportText({
text: await this.#textPromise,
requestId,
});
}
}
export { PdfTextExtractor };