1 files changed, 103 insertions, 0 deletions
diff --git a/devtools/client/framework/location-store.js b/devtools/client/framework/location-store.js
new file mode 100644
index 000000000..96deb0a99
--- /dev/null
+++ b/devtools/client/framework/location-store.js
@@ -0,0 +1,103 @@
+/* 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 SOURCE_TOKEN = "<:>";
+
+function LocationStore (store) {
+  this._store = store || new Map();
+}
+
+/**
+ * Method to get a promised location from the Store.
+ * @param location
+ * @returns Promise<Object>
+ */
+LocationStore.prototype.get = function (location) {
+  this._safeAccessInit(location.url);
+  return this._store.get(location.url).get(location);
+};
+
+/**
+ * Method to set a promised location to the Store
+ * @param location
+ * @param promisedLocation
+ */
+LocationStore.prototype.set = function (location, promisedLocation = null) {
+  this._safeAccessInit(location.url);
+  this._store.get(location.url).set(serialize(location), promisedLocation);
+};
+
+/**
+ * Utility method to verify if key exists in Store before accessing it.
+ * If not, initializing it.
+ * @param url
+ * @private
+ */
+LocationStore.prototype._safeAccessInit = function (url) {
+  if (!this._store.has(url)) {
+    this._store.set(url, new Map());
+  }
+};
+
+/**
+ * Utility proxy method to Map.clear() method
+ */
+LocationStore.prototype.clear = function () {
+  this._store.clear();
+};
+
+/**
+ * Retrieves an object containing all locations to be resolved when `source-updated`
+ * event is triggered.
+ * @param url
+ * @returns {Array<String>}
+ */
+LocationStore.prototype.getByURL = function (url){
+  if (this._store.has(url)) {
+    return [...this._store.get(url).keys()];
+  }
+  return [];
+};
+
+/**
+ * Invalidates the stale location promises from the store when `source-updated`
+ * event is triggered, and when FrameView unsubscribes from a location.
+ * @param url
+ */
+LocationStore.prototype.clearByURL = function (url) {
+  this._safeAccessInit(url);
+  this._store.set(url, new Map());
+};
+
+exports.LocationStore = LocationStore;
+exports.serialize = serialize;
+exports.deserialize = deserialize;
+
+/**
+ * Utility method to serialize the source
+ * @param source
+ * @returns {string}
+ */
+function serialize(source) {
+  let { url, line, column } = source;
+  line = line || 0;
+  column = column || 0;
+  return `${url}${SOURCE_TOKEN}${line}${SOURCE_TOKEN}${column}`;
+};
+
+/**
+ * Utility method to serialize the source
+ * @param source
+ * @returns Object
+ */
+function deserialize(source) {
+  let [ url, line, column ] = source.split(SOURCE_TOKEN);
+  line = parseInt(line);
+  column = parseInt(column);
+  if (column === 0) {
+    return { url, line };
+  }
+  return { url, line, column };
+};