1 files changed, 58 insertions, 0 deletions
diff --git a/dom/base/LocationHelper.jsm b/dom/base/LocationHelper.jsm
new file mode 100644
index 0000000000..9554fd491d
--- /dev/null
+++ b/dom/base/LocationHelper.jsm
@@ -0,0 +1,58 @@
+/* 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 EXPORTED_SYMBOLS = ["LocationHelper"];
+
+function isPublic(ap) {
+  let mask = "_nomap";
+  let result = ap.ssid.indexOf(mask, ap.ssid.length - mask.length);
+  return result == -1;
+}
+
+function sort(a, b) {
+  return b.signal - a.signal;
+}
+
+function encode(ap) {
+  return { macAddress: ap.mac, signalStrength: ap.signal };
+}
+
+/**
+ * Shared utility functions for modules dealing with
+ * Location Services.
+ */
+
+class LocationHelper {
+  static formatWifiAccessPoints(accessPoints) {
+    return accessPoints
+      .filter(isPublic)
+      .sort(sort)
+      .map(encode);
+  }
+
+  /**
+   * Calculate the distance between 2 points using the Haversine formula.
+   * https://en.wikipedia.org/wiki/Haversine_formula
+   */
+  static distance(p1, p2) {
+    let rad = x => (x * Math.PI) / 180;
+    // Radius of the earth.
+    let R = 6371e3;
+    let lat = rad(p2.lat - p1.lat);
+    let lng = rad(p2.lng - p1.lng);
+
+    let a =
+      Math.sin(lat / 2) * Math.sin(lat / 2) +
+      Math.cos(rad(p1.lat)) *
+        Math.cos(rad(p2.lat)) *
+        Math.sin(lng / 2) *
+        Math.sin(lng / 2);
+
+    let c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+
+    return R * c;
+  }
+}