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/*
* Copyright (C) 2020-2021 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/>.
*/
/**
* Class which can read text and images from the clipboard.
*/
class ClipboardReader {
/**
* Creates a new instances of a clipboard reader.
* @param document The Document object to be used, or null for no support.
* @param pasteTargetSelector The selector for the paste target element.
* @param imagePasteTargetSelector The selector for the image paste target element.
*/
constructor({document=null, pasteTargetSelector=null, imagePasteTargetSelector=null, mediaUtility=null}) {
this._document = document;
this._browser = null;
this._pasteTarget = null;
this._pasteTargetSelector = pasteTargetSelector;
this._imagePasteTarget = null;
this._imagePasteTargetSelector = imagePasteTargetSelector;
this._mediaUtility = mediaUtility;
}
/**
* Gets the browser being used.
*/
get browser() {
return this._browser;
}
/**
* Assigns the browser being used.
*/
set browser(value) {
this._browser = value;
}
/**
* Gets the text in the clipboard.
* @returns A string containing the clipboard text.
* @throws Error if not supported.
*/
async getText() {
/*
Notes:
document.execCommand('paste') 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()) {
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');
}
let target = this._pasteTarget;
if (target === null) {
target = document.querySelector(this._pasteTargetSelector);
if (target === null) {
throw new Error('Clipboard paste target does not exist');
}
this._pasteTarget = target;
}
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 A string containing a data URL of the image file, or null if no image was found.
* @throws Error if not supported.
*/
async getImage() {
// See browser-specific notes in getText
if (
this._isFirefox() &&
this._mediaUtility !== null &&
typeof navigator.clipboard !== 'undefined' &&
typeof navigator.clipboard.read === 'function'
) {
// This function is behind the Firefox flag: dom.events.asyncClipboard.dataTransfer
let files;
try {
({files} = await navigator.clipboard.read());
} catch (e) {
return null;
}
for (const file of files) {
if (this._mediaUtility.getFileExtensionFromImageMediaType(file.type) !== null) {
return await this._readFileAsDataURL(file);
}
}
return null;
}
const document = this._document;
if (document === null) {
throw new Error('Clipboard reading not supported in this context');
}
let target = this._imagePasteTarget;
if (target === null) {
target = document.querySelector(this._imagePasteTargetSelector);
if (target === null) {
throw new Error('Clipboard paste target does not exist');
}
this._imagePasteTarget = target;
}
target.focus();
document.execCommand('paste');
const image = target.querySelector('img[src^="data:"]');
const result = (image !== null ? image.getAttribute('src') : null);
for (const image2 of target.querySelectorAll('img')) {
image2.removeAttribute('src');
}
target.textContent = '';
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);
});
}
}
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