1 files changed, 158 insertions, 0 deletions
diff --git a/toolkit/components/enterprisepolicies/macOSPoliciesParser.sys.mjs b/toolkit/components/enterprisepolicies/macOSPoliciesParser.sys.mjs
new file mode 100644
index 0000000000..9786d3b374
--- /dev/null
+++ b/toolkit/components/enterprisepolicies/macOSPoliciesParser.sys.mjs
@@ -0,0 +1,158 @@
+/* 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/. */
+
+const PREF_LOGLEVEL = "browser.policies.loglevel";
+
+const lazy = {};
+
+ChromeUtils.defineLazyGetter(lazy, "log", () => {
+  let { ConsoleAPI } = ChromeUtils.importESModule(
+    "resource://gre/modules/Console.sys.mjs"
+  );
+  return new ConsoleAPI({
+    prefix: "macOSPoliciesParser.jsm",
+    // tip: set maxLogLevel to "debug" and use log.debug() to create detailed
+    // messages during development. See LOG_LEVELS in Console.sys.mjs for details.
+    maxLogLevel: "error",
+    maxLogLevelPref: PREF_LOGLEVEL,
+  });
+});
+
+export var macOSPoliciesParser = {
+  readPolicies(reader) {
+    let nativePolicies = reader.readPreferences();
+    if (!nativePolicies) {
+      return null;
+    }
+
+    nativePolicies = this.unflatten(nativePolicies);
+    nativePolicies = this.removeUnknownPolicies(nativePolicies);
+
+    // Need an extra check here so we don't
+    // JSON.stringify if we aren't in debug mode
+    if (lazy.log.maxLogLevel == "debug") {
+      lazy.log.debug(JSON.stringify(nativePolicies, null, 2));
+    }
+
+    return nativePolicies;
+  },
+
+  removeUnknownPolicies(policies) {
+    let { schema } = ChromeUtils.importESModule(
+      "resource:///modules/policies/schema.sys.mjs"
+    );
+
+    for (let policyName of Object.keys(policies)) {
+      if (!schema.properties.hasOwnProperty(policyName)) {
+        lazy.log.debug(`Removing unknown policy: ${policyName}`);
+        delete policies[policyName];
+      }
+    }
+
+    return policies;
+  },
+
+  unflatten(input, delimiter = "__") {
+    let ret = {};
+
+    for (let key of Object.keys(input)) {
+      if (!key.includes(delimiter)) {
+        // Short-circuit for policies that are not specified in
+        // the flat format.
+        ret[key] = input[key];
+        continue;
+      }
+
+      lazy.log.debug(`Unflattening policy key "${key}".`);
+
+      let subkeys = key.split(delimiter);
+
+      // `obj`: is the intermediate step into the unflattened
+      // return object. For example, for an input:
+      //
+      // Foo__Bar__Baz: 5,
+      //
+      // when the subkey being iterated is Bar, then `obj` will be
+      // the Bar object being constructed, as represented below:
+      //
+      // ret = {
+      //   Foo = {
+      //     Bar = {   <---- obj
+      //       Baz: 5,
+      //     }
+      //   }
+      // }
+      let obj = ret;
+
+      // Iterate until the second to last subkey, as the last one
+      // needs special handling afterwards.
+      for (let i = 0; i < subkeys.length - 1; i++) {
+        let subkey = subkeys[i];
+
+        if (!isValidSubkey(subkey)) {
+          lazy.log.error(
+            `Error in key ${key}: can't use indexes bigger than 50.`
+          );
+          continue;
+        }
+
+        if (!obj[subkey]) {
+          // if this subkey hasn't been seen yet, create the object
+          // for it, which could be an array if the next subkey is
+          // a number.
+          //
+          // For example, in the following examples:
+          // A)
+          // Foo__Bar__0
+          // Foo__Bar__1
+          //
+          // B)
+          // Foo__Bar__Baz
+          // Foo__Bar__Qux
+          //
+          // If the subkey being analysed right now is Bar, then in example A
+          // we'll create an array to accomodate the numeric entries.
+          // Otherwise, if it's example B, we'll create an object to host all
+          // the named keys.
+          if (Number.isInteger(Number(subkeys[i + 1]))) {
+            obj[subkey] = [];
+          } else {
+            obj[subkey] = {};
+          }
+        }
+
+        obj = obj[subkey];
+      }
+
+      let lastSubkey = subkeys[subkeys.length - 1];
+      if (!isValidSubkey(lastSubkey)) {
+        lazy.log.error(
+          `Error in key ${key}: can't use indexes bigger than 50.`
+        );
+        continue;
+      }
+
+      // In the last subkey, we assign it the value by accessing the input
+      // object again with the full key. For example, in the case:
+      //
+      // input = {"Foo__Bar__Baz": 5}
+      //
+      // what we're doing in practice is:
+      //
+      // ret["Foo"]["Bar"]["Baz"] = input["Foo__Bar__Baz"];
+      // \_______ _______/   |
+      //         v           |
+      //        obj      last subkey
+
+      obj[lastSubkey] = input[key];
+    }
+
+    return ret;
+  },
+};
+
+function isValidSubkey(subkey) {
+  let valueAsNumber = Number(subkey);
+  return Number.isNaN(valueAsNumber) || valueAsNumber <= 50;
+}