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+/*
+ * Copyright (C) 2020 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}) {
+ this._document = document;
+ this._browser = null;
+ this._pasteTarget = null;
+ this._pasteTargetSelector = pasteTargetSelector;
+ this._imagePasteTarget = null;
+ this._imagePasteTargetSelector = imagePasteTargetSelector;
+ }
+
+ /**
+ * 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.
+ This may be a bug: 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()) {
+ return await navigator.clipboard.readText();
+ }
+
+ const document = this._document;
+ if (document === null) {
+ throw new Error('Not supported');
+ }
+
+ 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()) {
+ if (typeof navigator.clipboard !== 'undefined' && typeof navigator.clipboard.read === 'function') {
+ // This function is behind the flag: dom.events.asyncClipboard.dataTransfer
+ const {files} = await navigator.clipboard.read();
+ if (files.length === 0) { return null; }
+ const result = await this._readFileAsDataURL(files[0]);
+ return result;
+ }
+ }
+
+ const document = this._document;
+ if (document === null) {
+ throw new Error('Not supported');
+ }
+
+ 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);
+ 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);
+ });
+ }
+}