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diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/globals.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/globals.js
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+/**
+ * @fileoverview functions for scanning an AST for globals including
+ *               traversing referenced scripts.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+"use strict";
+
+const path = require("path");
+const fs = require("fs");
+const helpers = require("./helpers");
+const htmlparser = require("htmlparser2");
+
+/**
+ * Parses a list of "name:boolean_value" or/and "name" options divided by comma
+ * or whitespace.
+ *
+ * This function was copied from eslint.js
+ *
+ * @param {string} string The string to parse.
+ * @param {Comment} comment The comment node which has the string.
+ * @returns {Object} Result map object of names and boolean values
+ */
+function parseBooleanConfig(string, comment) {
+  let items = {};
+
+  // Collapse whitespace around : to make parsing easier
+  string = string.replace(/\s*:\s*/g, ":");
+  // Collapse whitespace around ,
+  string = string.replace(/\s*,\s*/g, ",");
+
+  string.split(/\s|,+/).forEach(function(name) {
+    if (!name) {
+      return;
+    }
+
+    let pos = name.indexOf(":");
+    let value;
+    if (pos !== -1) {
+      value = name.substring(pos + 1, name.length);
+      name = name.substring(0, pos);
+    }
+
+    items[name] = {
+      value: value === "true",
+      comment,
+    };
+  });
+
+  return items;
+}
+
+/**
+ * Global discovery can require parsing many files. This map of
+ * {String} => {Object} caches what globals were discovered for a file path.
+ */
+const globalCache = new Map();
+
+/**
+ * Global discovery can occasionally meet circular dependencies due to the way
+ * js files are included via html/xhtml files etc. This set is used to avoid
+ * getting into loops whilst the discovery is in progress.
+ */
+var globalDiscoveryInProgressForFiles = new Set();
+
+/**
+ * When looking for globals in HTML files, it can be common to have more than
+ * one script tag with inline javascript. These will normally be called together,
+ * so we store the globals for just the last HTML file processed.
+ */
+var lastHTMLGlobals = {};
+
+/**
+ * An object that returns found globals for given AST node types. Each prototype
+ * property should be named for a node type and accepts a node parameter and a
+ * parents parameter which is a list of the parent nodes of the current node.
+ * Each returns an array of globals found.
+ *
+ * @param  {String} filePath
+ *         The absolute path of the file being parsed.
+ */
+function GlobalsForNode(filePath, context) {
+  this.path = filePath;
+  this.context = context;
+
+  if (this.path) {
+    this.dirname = path.dirname(this.path);
+  } else {
+    this.dirname = null;
+  }
+}
+
+GlobalsForNode.prototype = {
+  Program(node) {
+    let globals = [];
+    for (let comment of node.comments) {
+      if (comment.type !== "Block") {
+        continue;
+      }
+      let value = comment.value.trim();
+      value = value.replace(/\n/g, "");
+
+      // We have to discover any globals that ESLint would have defined through
+      // comment directives.
+      let match = /^globals?\s+(.+)/.exec(value);
+      if (match) {
+        let values = parseBooleanConfig(match[1].trim(), node);
+        for (let name of Object.keys(values)) {
+          globals.push({
+            name,
+            writable: values[name].value,
+          });
+        }
+        // We matched globals, so we won't match import-globals-from.
+        continue;
+      }
+
+      match = /^import-globals-from\s+(.+)$/.exec(value);
+      if (!match) {
+        continue;
+      }
+
+      if (!this.dirname) {
+        // If this is testing context without path, ignore import.
+        return globals;
+      }
+
+      let filePath = match[1].trim();
+
+      if (filePath.endsWith(".mjs")) {
+        if (this.context) {
+          this.context.report(
+            comment,
+            "import-globals-from does not support module files - use a direct import instead"
+          );
+        } else {
+          // Fall back to throwing an error, as we do not have a context in all situations,
+          // e.g. when loading the environment.
+          throw new Error(
+            "import-globals-from does not support module files - use a direct import instead"
+          );
+        }
+        continue;
+      }
+
+      if (!path.isAbsolute(filePath)) {
+        filePath = path.resolve(this.dirname, filePath);
+      } else {
+        filePath = path.join(helpers.rootDir, filePath);
+      }
+      globals = globals.concat(module.exports.getGlobalsForFile(filePath));
+    }
+
+    return globals;
+  },
+
+  ExpressionStatement(node, parents, globalScope) {
+    let isGlobal = helpers.getIsGlobalThis(parents);
+    let globals = [];
+
+    // Note: We check the expression types here and only call the necessary
+    // functions to aid performance.
+    if (node.expression.type === "AssignmentExpression") {
+      globals = helpers.convertThisAssignmentExpressionToGlobals(
+        node,
+        isGlobal
+      );
+    } else if (node.expression.type === "CallExpression") {
+      globals = helpers.convertCallExpressionToGlobals(node, isGlobal);
+    }
+
+    // Here we assume that if importScripts is set in the global scope, then
+    // this is a worker. It would be nice if eslint gave us a way of getting
+    // the environment directly.
+    //
+    // If this is testing context without path, ignore import.
+    if (globalScope && globalScope.set.get("importScripts") && this.dirname) {
+      let workerDetails = helpers.convertWorkerExpressionToGlobals(
+        node,
+        isGlobal,
+        this.dirname
+      );
+      globals = globals.concat(workerDetails);
+    }
+
+    return globals;
+  },
+};
+
+module.exports = {
+  /**
+   * Returns all globals for a given file. Recursively searches through
+   * import-globals-from directives and also includes globals defined by
+   * standard eslint directives.
+   *
+   * @param  {String} filePath
+   *         The absolute path of the file to be parsed.
+   * @param  {Object} astOptions
+   *         Extra options to pass to the parser.
+   * @return {Array}
+   *         An array of objects that contain details about the globals:
+   *         - {String} name
+   *                    The name of the global.
+   *         - {Boolean} writable
+   *                     If the global is writeable or not.
+   */
+  getGlobalsForFile(filePath, astOptions = {}) {
+    if (globalCache.has(filePath)) {
+      return globalCache.get(filePath);
+    }
+
+    if (globalDiscoveryInProgressForFiles.has(filePath)) {
+      // We're already processing this file, so return an empty set for now -
+      // the initial processing will pick up on the globals for this file.
+      return [];
+    }
+    globalDiscoveryInProgressForFiles.add(filePath);
+
+    let content = fs.readFileSync(filePath, "utf8");
+
+    // Parse the content into an AST
+    let { ast, scopeManager, visitorKeys } = helpers.parseCode(
+      content,
+      astOptions
+    );
+
+    // Discover global declarations
+    let globalScope = scopeManager.acquire(ast);
+
+    let globals = Object.keys(globalScope.variables).map(v => ({
+      name: globalScope.variables[v].name,
+      writable: true,
+    }));
+
+    // Walk over the AST to find any of our custom globals
+    let handler = new GlobalsForNode(filePath);
+
+    helpers.walkAST(ast, visitorKeys, (type, node, parents) => {
+      if (type in handler) {
+        let newGlobals = handler[type](node, parents, globalScope);
+        globals.push.apply(globals, newGlobals);
+      }
+    });
+
+    globalCache.set(filePath, globals);
+
+    globalDiscoveryInProgressForFiles.delete(filePath);
+    return globals;
+  },
+
+  /**
+   * Returns all globals for a code.
+   * This is only for testing.
+   *
+   * @param  {String} code
+   *         The JS code
+   * @param  {Object} astOptions
+   *         Extra options to pass to the parser.
+   * @return {Array}
+   *         An array of objects that contain details about the globals:
+   *         - {String} name
+   *                    The name of the global.
+   *         - {Boolean} writable
+   *                     If the global is writeable or not.
+   */
+  getGlobalsForCode(code, astOptions = {}) {
+    // Parse the content into an AST
+    let { ast, scopeManager, visitorKeys } = helpers.parseCode(
+      code,
+      astOptions,
+      { useBabel: false }
+    );
+
+    // Discover global declarations
+    let globalScope = scopeManager.acquire(ast);
+
+    let globals = Object.keys(globalScope.variables).map(v => ({
+      name: globalScope.variables[v].name,
+      writable: true,
+    }));
+
+    // Walk over the AST to find any of our custom globals
+    let handler = new GlobalsForNode(null);
+
+    helpers.walkAST(ast, visitorKeys, (type, node, parents) => {
+      if (type in handler) {
+        let newGlobals = handler[type](node, parents, globalScope);
+        globals.push.apply(globals, newGlobals);
+      }
+    });
+
+    return globals;
+  },
+
+  /**
+   * Returns all the globals for an html file that are defined by imported
+   * scripts (i.e. <script src="foo.js">).
+   *
+   * This function will cache results for one html file only - we expect
+   * this to be called sequentially for each chunk of a HTML file, rather
+   * than chucks of different files in random order.
+   *
+   * @param  {String} filePath
+   *         The absolute path of the file to be parsed.
+   * @return {Array}
+   *         An array of objects that contain details about the globals:
+   *         - {String} name
+   *                    The name of the global.
+   *         - {Boolean} writable
+   *                     If the global is writeable or not.
+   */
+  getImportedGlobalsForHTMLFile(filePath) {
+    if (lastHTMLGlobals.filename === filePath) {
+      return lastHTMLGlobals.globals;
+    }
+
+    let dir = path.dirname(filePath);
+    let globals = [];
+
+    let content = fs.readFileSync(filePath, "utf8");
+    let scriptSrcs = [];
+
+    // We use htmlparser as this ensures we find the script tags correctly.
+    let parser = new htmlparser.Parser(
+      {
+        onopentag(name, attribs) {
+          if (name === "script" && "src" in attribs) {
+            scriptSrcs.push({
+              src: attribs.src,
+              type:
+                "type" in attribs && attribs.type == "module"
+                  ? "module"
+                  : "script",
+            });
+          }
+        },
+      },
+      {
+        xmlMode: filePath.endsWith("xhtml"),
+      }
+    );
+
+    parser.parseComplete(content);
+
+    for (let script of scriptSrcs) {
+      // Ensure that the script src isn't just "".
+      if (!script.src) {
+        continue;
+      }
+      let scriptName;
+      if (script.src.includes("http:")) {
+        // We don't handle this currently as the paths are complex to match.
+      } else if (script.src.includes("chrome")) {
+        // This is one way of referencing test files.
+        script.src = script.src.replace("chrome://mochikit/content/", "/");
+        scriptName = path.join(
+          helpers.rootDir,
+          "testing",
+          "mochitest",
+          script.src
+        );
+      } else if (script.src.includes("SimpleTest")) {
+        // This is another way of referencing test files...
+        scriptName = path.join(
+          helpers.rootDir,
+          "testing",
+          "mochitest",
+          script.src
+        );
+      } else if (script.src.startsWith("/tests/")) {
+        scriptName = path.join(helpers.rootDir, script.src.substring(7));
+      } else {
+        // Fallback to hoping this is a relative path.
+        scriptName = path.join(dir, script.src);
+      }
+      if (scriptName && fs.existsSync(scriptName)) {
+        globals.push(
+          ...module.exports.getGlobalsForFile(scriptName, {
+            ecmaVersion: helpers.getECMAVersion(),
+            sourceType: script.type,
+          })
+        );
+      }
+    }
+
+    lastHTMLGlobals.filePath = filePath;
+    return (lastHTMLGlobals.globals = globals);
+  },
+
+  /**
+   * Intended to be used as-is for an ESLint rule that parses for globals in
+   * the current file and recurses through import-globals-from directives.
+   *
+   * @param  {Object} context
+   *         The ESLint parsing context.
+   */
+  getESLintGlobalParser(context) {
+    let globalScope;
+
+    let parser = {
+      Program(node) {
+        globalScope = context.getScope();
+      },
+    };
+    let filename = context.getFilename();
+
+    let extraHTMLGlobals = [];
+    if (filename.endsWith(".html") || filename.endsWith(".xhtml")) {
+      extraHTMLGlobals = module.exports.getImportedGlobalsForHTMLFile(filename);
+    }
+
+    // Install thin wrappers around GlobalsForNode
+    let handler = new GlobalsForNode(helpers.getAbsoluteFilePath(context));
+
+    for (let type of Object.keys(GlobalsForNode.prototype)) {
+      parser[type] = function(node) {
+        if (type === "Program") {
+          globalScope = context.getScope();
+          helpers.addGlobals(extraHTMLGlobals, globalScope);
+        }
+        let globals = handler[type](node, context.getAncestors(), globalScope);
+        helpers.addGlobals(
+          globals,
+          globalScope,
+          node.type !== "Program" && node
+        );
+      };
+    }
+
+    return parser;
+  },
+};