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/*
* Copyright (C) 2023 Yomitan Authors
* 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 = '';
}
}
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