提交qiming-noVNC

qiming-noVNC/core/util/browser.js

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+/*
+ * noVNC: HTML5 VNC client
+ * Copyright (C) 2019 The noVNC authors
+ * Licensed under MPL 2.0 (see LICENSE.txt)
+ *
+ * See README.md for usage and integration instructions.
+ *
+ * Browser feature support detection
+ */
+
+import * as Log from './logging.js';
+import Base64 from '../base64.js';
+
+// Touch detection
+export let isTouchDevice = ('ontouchstart' in document.documentElement) ||
+                                 // required for Chrome debugger
+                                 (document.ontouchstart !== undefined) ||
+                                 // required for MS Surface
+                                 (navigator.maxTouchPoints > 0) ||
+                                 (navigator.msMaxTouchPoints > 0);
+window.addEventListener('touchstart', function onFirstTouch() {
+    isTouchDevice = true;
+    window.removeEventListener('touchstart', onFirstTouch, false);
+}, false);
+
+
+// The goal is to find a certain physical width, the devicePixelRatio
+// brings us a bit closer but is not optimal.
+export let dragThreshold = 10 * (window.devicePixelRatio || 1);
+
+let _supportsCursorURIs = false;
+
+try {
+    const target = document.createElement('canvas');
+    target.style.cursor = 'url("data:image/x-icon;base64,AAACAAEACAgAAAIAAgA4AQAAFgAAACgAAAAIAAAAEAAAAAEAIAAAAAAAEAAAAAAAAAAAAAAAAAAAAAAAAAD/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////AAAAAAAAAAAAAAAAAAAAAA==") 2 2, default';
+
+    if (target.style.cursor.indexOf("url") === 0) {
+        Log.Info("Data URI scheme cursor supported");
+        _supportsCursorURIs = true;
+    } else {
+        Log.Warn("Data URI scheme cursor not supported");
+    }
+} catch (exc) {
+    Log.Error("Data URI scheme cursor test exception: " + exc);
+}
+
+export const supportsCursorURIs = _supportsCursorURIs;
+
+let _hasScrollbarGutter = true;
+try {
+    // Create invisible container
+    const container = document.createElement('div');
+    container.style.visibility = 'hidden';
+    container.style.overflow = 'scroll'; // forcing scrollbars
+    document.body.appendChild(container);
+
+    // Create a div and place it in the container
+    const child = document.createElement('div');
+    container.appendChild(child);
+
+    // Calculate the difference between the container's full width
+    // and the child's width - the difference is the scrollbars
+    const scrollbarWidth = (container.offsetWidth - child.offsetWidth);
+
+    // Clean up
+    container.parentNode.removeChild(container);
+
+    _hasScrollbarGutter = scrollbarWidth != 0;
+} catch (exc) {
+    Log.Error("Scrollbar test exception: " + exc);
+}
+export const hasScrollbarGutter = _hasScrollbarGutter;
+
+export let supportsWebCodecsH264Decode = false;
+
+async function _checkWebCodecsH264DecodeSupport() {
+    if (!('VideoDecoder' in window)) {
+        return false;
+    }
+
+    // We'll need to make do with some placeholders here
+    const config = {
+        codec: 'avc1.42401f',
+        codedWidth: 1920,
+        codedHeight: 1080,
+        optimizeForLatency: true,
+    };
+
+    let support = await VideoDecoder.isConfigSupported(config);
+    if (!support.supported) {
+        return false;
+    }
+
+    // Firefox incorrectly reports supports for H.264 under some
+    // circumstances, so we need to actually test a real frame
+    // https://bugzilla.mozilla.org/show_bug.cgi?id=1932392
+
+    const data = new Uint8Array(Base64.decode(
+        'AAAAAWdCwBTZnpuAgICgAAADACAAAAZB4oVNAAAAAWjJYyyAAAABBgX//4Hc' +
+        'Rem95tlIt5Ys2CDZI+7veDI2NCAtIGNvcmUgMTY0IHIzMTA4IDMxZTE5Zjkg' +
+        'LSBILjI2NC9NUEVHLTQgQVZDIGNvZGVjIC0gQ29weWxlZnQgMjAwMy0yMDIz' +
+        'IC0gaHR0cDovL3d3dy52aWRlb2xhbi5vcmcveDI2NC5odG1sIC0gb3B0aW9u' +
+        'czogY2FiYWM9MCByZWY9NSBkZWJsb2NrPTE6MDowIGFuYWx5c2U9MHgxOjB4' +
+        'MTExIG1lPWhleCBzdWJtZT04IHBzeT0xIHBzeV9yZD0xLjAwOjAuMDAgbWl4' +
+        'ZWRfcmVmPTEgbWVfcmFuZ2U9MTYgY2hyb21hX21lPTEgdHJlbGxpcz0yIDh4' +
+        'OGRjdD0wIGNxbT0wIGRlYWR6b25lPTIxLDExIGZhc3RfcHNraXA9MSBjaHJv' +
+        'bWFfcXBfb2Zmc2V0PS0yIHRocmVhZHM9MSBsb29rYWhlYWRfdGhyZWFkcz0x' +
+        'IHNsaWNlZF90aHJlYWRzPTAgbnI9MCBkZWNpbWF0ZT0xIGludGVybGFjZWQ9' +
+        'MCBibHVyYXlfY29tcGF0PTAgY29uc3RyYWluZWRfaW50cmE9MCBiZnJhbWVz' +
+        'PTAgd2VpZ2h0cD0wIGtleWludD1pbmZpbml0ZSBrZXlpbnRfbWluPTI1IHNj' +
+        'ZW5lY3V0PTQwIGludHJhX3JlZnJlc2g9MCByY19sb29rYWhlYWQ9NTAgcmM9' +
+        'YWJyIG1idHJlZT0xIGJpdHJhdGU9NDAwIHJhdGV0b2w9MS4wIHFjb21wPTAu' +
+        'NjAgcXBtaW49MCBxcG1heD02OSBxcHN0ZXA9NCBpcF9yYXRpbz0xLjQwIGFx' +
+        'PTE6MS4wMACAAAABZYiEBrxmKAAPVccAAS044AA5DRJMnkycJk4TPw=='));
+
+    let gotframe = false;
+    let error = null;
+
+    let decoder = new VideoDecoder({
+        output: (frame) => { gotframe = true; },
+        error: (e) => { error = e; },
+    });
+    let chunk = new EncodedVideoChunk({
+        timestamp: 0,
+        type: 'key',
+        data: data,
+    });
+
+    decoder.configure(config);
+    decoder.decode(chunk);
+    try {
+        await decoder.flush();
+    } catch (e) {
+        // Firefox incorrectly throws an exception here
+        // https://bugzilla.mozilla.org/show_bug.cgi?id=1932566
+        error = e;
+    }
+
+    // Firefox fails to deliver the error on Windows, so we need to
+    // check if we got a frame instead
+    // https://bugzilla.mozilla.org/show_bug.cgi?id=1932579
+    if (!gotframe) {
+        return false;
+    }
+
+    if (error !== null) {
+        return false;
+    }
+
+    return true;
+}
+supportsWebCodecsH264Decode = await _checkWebCodecsH264DecodeSupport();
+
+/*
+ * The functions for detection of platforms and browsers below are exported
+ * but the use of these should be minimized as much as possible.
+ *
+ * It's better to use feature detection than platform detection.
+ */
+
+/* OS */
+
+export function isMac() {
+    return !!(/mac/i).exec(navigator.platform);
+}
+
+export function isWindows() {
+    return !!(/win/i).exec(navigator.platform);
+}
+
+export function isIOS() {
+    return (!!(/ipad/i).exec(navigator.platform) ||
+            !!(/iphone/i).exec(navigator.platform) ||
+            !!(/ipod/i).exec(navigator.platform));
+}
+
+export function isAndroid() {
+    /* Android sets navigator.platform to Linux :/ */
+    return !!navigator.userAgent.match('Android ');
+}
+
+export function isChromeOS() {
+    /* ChromeOS sets navigator.platform to Linux :/ */
+    return !!navigator.userAgent.match(' CrOS ');
+}
+
+/* Browser */
+
+export function isSafari() {
+    return !!navigator.userAgent.match('Safari/...') &&
+           !navigator.userAgent.match('Chrome/...') &&
+           !navigator.userAgent.match('Chromium/...') &&
+           !navigator.userAgent.match('Epiphany/...');
+}
+
+export function isFirefox() {
+    return !!navigator.userAgent.match('Firefox/...') &&
+           !navigator.userAgent.match('Seamonkey/...');
+}
+
+export function isChrome() {
+    return !!navigator.userAgent.match('Chrome/...') &&
+           !navigator.userAgent.match('Chromium/...') &&
+           !navigator.userAgent.match('Edg/...') &&
+           !navigator.userAgent.match('OPR/...');
+}
+
+export function isChromium() {
+    return !!navigator.userAgent.match('Chromium/...');
+}
+
+export function isOpera() {
+    return !!navigator.userAgent.match('OPR/...');
+}
+
+export function isEdge() {
+    return !!navigator.userAgent.match('Edg/...');
+}
+
+/* Engine */
+
+export function isGecko() {
+    return !!navigator.userAgent.match('Gecko/...');
+}
+
+export function isWebKit() {
+    return !!navigator.userAgent.match('AppleWebKit/...') &&
+           !navigator.userAgent.match('Chrome/...');
+}
+
+export function isBlink() {
+    return !!navigator.userAgent.match('Chrome/...');
+}