/* * Copyright (C) 2020-2022 Yomichan Authors * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <https://www.gnu.org/licenses/>. */ /* global * MediaUtil */ /** * Class which can read text and images from the clipboard. */ class ClipboardReader { /** * Creates a new instances of a clipboard reader. * @param {object} details Details about how to set up the instance. * @param {?Document} details.document The Document object to be used, or null for no support. * @param {?string} details.pasteTargetSelector The selector for the paste target element. * @param {?string} details.richContentPasteTargetSelector The selector for the rich content paste target element. */ constructor({document=null, pasteTargetSelector=null, richContentPasteTargetSelector=null}) { this._document = document; this._browser = null; this._pasteTarget = null; this._pasteTargetSelector = pasteTargetSelector; this._richContentPasteTarget = null; this._richContentPasteTargetSelector = richContentPasteTargetSelector; } /** * Gets the browser being used. * @type {?string} */ get browser() { return this._browser; } /** * Assigns the browser being used. */ set browser(value) { this._browser = value; } /** * Gets the text in the clipboard. * @param {boolean} useRichText Whether or not to use rich text for pasting, when possible. * @returns {string} A string containing the clipboard text. * @throws {Error} Error if not supported. */ async getText(useRichText) { /* Notes: document.execCommand('paste') sometimes doesn't work on Firefox. See: https://bugzilla.mozilla.org/show_bug.cgi?id=1603985 Therefore, navigator.clipboard.readText() is used on Firefox. navigator.clipboard.readText() can't be used in Chrome for two reasons: * Requires page to be focused, else it rejects with an exception. * When the page is focused, Chrome will request clipboard permission, despite already being an extension with clipboard permissions. It effectively asks for the non-extension permission for clipboard access. */ if (this._isFirefox() && !useRichText) { try { return await navigator.clipboard.readText(); } catch (e) { // Error is undefined, due to permissions throw new Error('Cannot read clipboard text; check extension permissions'); } } const document = this._document; if (document === null) { throw new Error('Clipboard reading not supported in this context'); } if (useRichText) { const target = this._getRichContentPasteTarget(); target.focus(); document.execCommand('paste'); const result = target.textContent; this._clearRichContent(target); return result; } else { const target = this._getPasteTarget(); target.value = ''; target.focus(); document.execCommand('paste'); const result = target.value; target.value = ''; return (typeof result === 'string' ? result : ''); } } /** * Gets the first image in the clipboard. * @returns {string} A string containing a data URL of the image file, or null if no image was found. * @throws {Error} Error if not supported. */ async getImage() { // See browser-specific notes in getText if ( this._isFirefox() && typeof navigator.clipboard !== 'undefined' && typeof navigator.clipboard.read === 'function' ) { // This function is behind the Firefox flag: dom.events.asyncClipboard.read // See: https://developer.mozilla.org/en-US/docs/Web/API/Clipboard/read#browser_compatibility let items; try { items = await navigator.clipboard.read(); } catch (e) { return null; } for (const item of items) { for (const type of item.types) { if (!MediaUtil.getFileExtensionFromImageMediaType(type)) { continue; } try { const blob = await item.getType(type); return await this._readFileAsDataURL(blob); } catch (e) { // NOP } } } return null; } const document = this._document; if (document === null) { throw new Error('Clipboard reading not supported in this context'); } const target = this._getRichContentPasteTarget(); target.focus(); document.execCommand('paste'); const image = target.querySelector('img[src^="data:"]'); const result = (image !== null ? image.getAttribute('src') : null); this._clearRichContent(target); return result; } // Private _isFirefox() { return (this._browser === 'firefox' || this._browser === 'firefox-mobile'); } _readFileAsDataURL(file) { return new Promise((resolve, reject) => { const reader = new FileReader(); reader.onload = () => resolve(reader.result); reader.onerror = () => reject(reader.error); reader.readAsDataURL(file); }); } _getPasteTarget() { if (this._pasteTarget === null) { this._pasteTarget = this._findPasteTarget(this._pasteTargetSelector); } return this._pasteTarget; } _getRichContentPasteTarget() { if (this._richContentPasteTarget === null) { this._richContentPasteTarget = this._findPasteTarget(this._richContentPasteTargetSelector); } return this._richContentPasteTarget; } _findPasteTarget(selector) { const target = this._document.querySelector(selector); if (target === null) { throw new Error('Clipboard paste target does not exist'); } return target; } _clearRichContent(element) { for (const image of element.querySelectorAll('img')) { image.removeAttribute('src'); image.removeAttribute('srcset'); } element.textContent = ''; } }