EventIndexPeg: Small refactor and change the init logic.

This changes the way the event index is initialized, if it's disabled in
the settings it will not be initialized at all, before only the crawler
loop was not being started.

src/indexing/EventIndexPeg.js

@@ -21,17 +21,19 @@ limitations under the License.
 
 import PlatformPeg from "../PlatformPeg";
 import EventIndex from "../indexing/EventIndex";
-import SettingsStore from '../settings/SettingsStore';
+import SettingsStore, {SettingLevel} from '../settings/SettingsStore';
 
 class EventIndexPeg {
     constructor() {
         this.index = null;
+        this._supportIsInstalled = false;
     }
 
     /**
-     * Create a new EventIndex and initialize it if the platform supports it.
+     * Initialize the EventIndexPeg and if event indexing is enabled initialize
+     * the event index.
      *
-     * @return {Promise<bool>} A promise that will resolve to true if an
+     * @return {Promise<boolean>} A promise that will resolve to true if an
      * EventIndex was successfully initialized, false otherwise.
      */
     async init() {
@@ -40,12 +42,32 @@ class EventIndexPeg {
         }
 
         const indexManager = PlatformPeg.get().getEventIndexingManager();
-        if (!indexManager || await indexManager.supportsEventIndexing() !== true) {
+        if (!indexManager) {
-            console.log("EventIndex: Platform doesn't support event indexing,",
+            console.log("EventIndex: Platform doesn't support event indexing, not initializing.");
-                        "not initializing.");
             return false;
         }
 
+        this._supportIsInstalled = await indexManager.supportsEventIndexing();
+
+        if (!this.supportIsInstalled()) {
+            console.log("EventIndex: Event indexing isn't installed for the platform, not initializing.");
+            return false;
+        }
+
+        if (!SettingsStore.getValueAt(SettingLevel.DEVICE, 'enableEventIndexing')) {
+            console.log("EventIndex: Event indexing is disabled, not initializing");
+            return false;
+        }
+
+        return this.initEventIndex();
+    }
+
+    /* Initialize the event index.
+     *
+     * @returns {boolean} True if the event index was succesfully initialized,
+     * false otherwise.
+     */
+    async initEventIndex() {
         const index = new EventIndex();
 
         try {
@@ -60,6 +82,29 @@ class EventIndexPeg {
         return true;
     }
 
+    /**
+     * Check if the current platform has support for event indexing.
+     *
+     * @return {boolean} True if it has support, false otherwise. Note that this
+     * does not mean that support is installed.
+     */
+    platformHasSupport(): boolean {
+        return PlatformPeg.get().getEventIndexingManager() !== null;
+    }
+
+    /**
+     * Check if event indexing support is installed for the platfrom.
+     *
+     * Event indexing might require additional optional modules to be installed,
+     * this tells us if those are installed. Note that this should only be
+     * called after the init() method was called.
+     *
+     * @return {boolean} True if support is installed, false otherwise.
+     */
+    supportIsInstalled(): boolean {
+        return this._supportIsInstalled;
+    }
+
     /**
      * Get the current event index.
      *