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2026-06-25 21:30:32 +00:00
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+/**
+ * @license
+ * Copyright The Closure Library Authors.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview Closure user agent detection.
+ * @see http://en.wikipedia.org/wiki/User_agent
+ * For more information on browser brand, platform, or device see the other
+ * sub-namespaces in goog.labs.userAgent (browser, platform, and device).
+ */
+
+goog.module('goog.labs.userAgent.engine');
+goog.module.declareLegacyNamespace();
+
+const googArray = goog.require('goog.array');
+const googString = goog.require('goog.string.internal');
+const util = goog.require('goog.labs.userAgent.util');
+
+/**
+ * @return {boolean} Whether the rendering engine is Presto.
+ */
+function isPresto() {
+  return util.matchUserAgent('Presto');
+}
+
+/**
+ * @return {boolean} Whether the rendering engine is Trident.
+ */
+function isTrident() {
+  // IE only started including the Trident token in IE8.
+  return util.matchUserAgent('Trident') || util.matchUserAgent('MSIE');
+}
+
+/**
+ * @return {boolean} Whether the rendering engine is EdgeHTML.
+ */
+function isEdge() {
+  return util.matchUserAgent('Edge');
+}
+
+/**
+ * @return {boolean} Whether the rendering engine is WebKit. This will return
+ * true for Chrome, Blink-based Opera (15+), Edge Chromium and Safari.
+ */
+function isWebKit() {
+  return util.matchUserAgentIgnoreCase('WebKit') && !isEdge();
+}
+
+/**
+ * @return {boolean} Whether the rendering engine is Gecko.
+ */
+function isGecko() {
+  return util.matchUserAgent('Gecko') && !isWebKit() && !isTrident() &&
+      !isEdge();
+}
+
+/**
+ * @return {string} The rendering engine's version or empty string if version
+ *     can't be determined.
+ */
+function getVersion() {
+  const userAgentString = util.getUserAgent();
+  if (userAgentString) {
+    const tuples = util.extractVersionTuples(userAgentString);
+
+    const engineTuple = getEngineTuple(tuples);
+    if (engineTuple) {
+      // In Gecko, the version string is either in the browser info or the
+      // Firefox version.  See Gecko user agent string reference:
+      // http://goo.gl/mULqa
+      if (engineTuple[0] == 'Gecko') {
+        return getVersionForKey(tuples, 'Firefox');
+      }
+
+      return engineTuple[1];
+    }
+
+    // MSIE has only one version identifier, and the Trident version is
+    // specified in the parenthetical. IE Edge is covered in the engine tuple
+    // detection.
+    const browserTuple = tuples[0];
+    let info;
+    if (browserTuple && (info = browserTuple[2])) {
+      const match = /Trident\/([^\s;]+)/.exec(info);
+      if (match) {
+        return match[1];
+      }
+    }
+  }
+  return '';
+}
+
+/**
+ * @param {!Array<!Array<string>>} tuples Extracted version tuples.
+ * @return {!Array<string>|undefined} The engine tuple or undefined if not
+ *     found.
+ */
+function getEngineTuple(tuples) {
+  if (!isEdge()) {
+    return tuples[1];
+  }
+  for (let i = 0; i < tuples.length; i++) {
+    const tuple = tuples[i];
+    if (tuple[0] == 'Edge') {
+      return tuple;
+    }
+  }
+}
+
+/**
+ * @param {string|number} version The version to check.
+ * @return {boolean} Whether the rendering engine version is higher or the same
+ *     as the given version.
+ */
+function isVersionOrHigher(version) {
+  return googString.compareVersions(getVersion(), version) >= 0;
+}
+
+/**
+ * @param {!Array<!Array<string>>} tuples Version tuples.
+ * @param {string} key The key to look for.
+ * @return {string} The version string of the given key, if present.
+ *     Otherwise, the empty string.
+ */
+function getVersionForKey(tuples, key) {
+  // TODO(nnaze): Move to util if useful elsewhere.
+
+  const pair = googArray.find(tuples, function(pair) {
+    return key == pair[0];
+  });
+
+  return pair && pair[1] || '';
+}
+
+exports = {
+  getVersion,
+  isEdge,
+  isGecko,
+  isPresto,
+  isTrident,
+  isVersionOrHigher,
+  isWebKit,
+};