Finish scrollback impl. Add UTs.

lib/store/webstorage.js

@@ -109,7 +109,7 @@
  * </pre>
  * @module store/webstorage
  */
-
+var DEBUG = true;  // set true to enable console logging.
 var utils = require("../utils");
 var Room = require("../models/room");
 var User = require("../models/user");
@@ -185,10 +185,12 @@ WebStorageStore.prototype.storeRoom = function(room) {
 WebStorageStore.prototype.getRoom = function(roomId) {
     // probe if room exists; break early if not. Every room should have state.
     if (!this.store.getItem(keyName(roomId, "state"))) {
+        debuglog("getRoom: No room with id %s found.", roomId);
         return null;
     }
     var timelineKeys = getTimelineIndices(this.store, roomId);
     if (timelineKeys.indexOf("live") !== -1) {
+        debuglog("getRoom: Live events found. Syncing timeline for %s", roomId);
         this._syncTimeline(roomId, timelineKeys);
     }
     return loadRoom(this.store, roomId, this.batchSize, this._tokens);
@@ -264,26 +266,32 @@ WebStorageStore.prototype.getUser = function(userId) {
 };
 
 /**
- * Retrieve scrollback for this room.
- * @param {Room} room The matrix room
+ * Retrieve scrollback for this room. Automatically adds events to the timeline.
+ * @param {Room} room The matrix room to add the events to the start of the timeline.
  * @param {integer} limit The max number of old events to retrieve.
  * @return {Array<Object>} An array of objects which will be at most 'limit'
  * length and at least 0. The objects are the raw event JSON. The last element
- * is the 'newest'.
+ * is the 'oldest' (for parity with homeserver scrollback APIs).
  */
 WebStorageStore.prototype.scrollback = function(room, limit) {
     if (room.storageToken === undefined || room.storageToken >= this._tokens.length) {
         return [];
     }
     // find the index of the earliest event in this room's timeline
+    var storeData = this._tokens[room.storageToken] || {};
     var i;
-    var earliestIndex = this._tokens[room.storageToken].earliestIndex;
-    var earliestEventId = room.timeline[0].getId();
+    var earliestIndex = storeData.earliestIndex;
+    var earliestEventId = room.timeline[0] ? room.timeline[0].getId() : null;
+    debuglog(
+        "scrollback in %s (timeline=%s msgs) i=%s, timeline[0].id=%s - req %s events",
+        room.roomId, room.timeline.length, earliestIndex, earliestEventId, limit
+    );
     var batch = this.store.getItem(
         keyName(room.roomId, "timeline", earliestIndex)
     );
     if (!batch) {
         // bad room or already at start, either way we have nothing to give.
+        debuglog("No batch with index %s found.", earliestIndex);
         return [];
     }
     // populate from this batch first
@@ -296,20 +304,34 @@ WebStorageStore.prototype.scrollback = function(room, limit) {
         var matrixEvent = new MatrixEvent(batch[i]);
         if (matrixEvent.getId() === earliestEventId) {
             foundEventId = true;
+            debuglog(
+                "Found timeline[0] event at position %s in batch %s",
+                i, earliestIndex
+            );
             continue;
         }
         if (!foundEventId) {
             continue;
         }
         // add entry
+        debuglog("Add event at position %s in batch %s", i, earliestIndex);
         scrollback.push(batch[i]);
         if (scrollback.length === limit) {
             break;
         }
     }
     if (scrollback.length === limit) {
+        debuglog("Batch has enough events to satisfy request.");
         return scrollback;
     }
+    if (!foundEventId) {
+        // the earliest index batch didn't contain the event. In other words,
+        // this timeline is at a state we don't know, so bail.
+        debuglog(
+            "Failed to find event ID %s in batch %s", earliestEventId, earliestIndex
+        );
+        return [];
+    }
 
     // get the requested earlier events from earlier batches
     while (scrollback.length < limit) {
@@ -317,15 +339,28 @@ WebStorageStore.prototype.scrollback = function(room, limit) {
         batch = this.store.getItem(keyName(room.roomId, "timeline", earliestIndex));
         if (!batch) {
             // no more events
+            debuglog("No batch found at index %s", earliestIndex);
             break;
         }
         for (i = batch.length - 1; i >= 0; i--) {
+            debuglog("Add event at position %s in batch %s", i, earliestIndex);
             scrollback.push(batch[i]);
             if (scrollback.length === limit) {
                 break;
             }
         }
     }
+    debuglog(
+        "Out of %s requested events, returning %s. New index=%s",
+        limit, scrollback.length, earliestIndex
+    );
+    room.addEventsToTimeline(utils.map(scrollback, function(e) {
+            return new MatrixEvent(e);
+    }), true);
+
+    this._tokens[room.storageToken] = {
+        earliestIndex: earliestIndex
+    };
     return scrollback;
 };
 
@@ -516,6 +551,12 @@ function keyName(roomId, key, index) {
     );
 }
 
+function debuglog() {
+    if (DEBUG) {
+        console.log.apply(console, arguments);
+    }
+}
+
 /*
 function delRoomStruct(store, roomId) {
     var prefix = "room_" + roomId;