WIP for fragment support

doc/FRAGMENTS.md

@@ -5,21 +5,31 @@
     - SortKey
         - FragmentId
         - EventIndex
- - write fragmentStore
+ - DONE: write fragmentStore
     - load all fragments
     - add a fragment (live on limited sync, or /context)
     - connect two fragments
     - update token on fragment (when filling gap or connecting two fragments)
 
     fragments can need connecting when filling a gap or creating a new /context fragment
- - adapt timelineStore
+ - DONE: adapt timelineStore
 
     how will fragments be exposed in timeline store?
         - all read operations are passed a fragment id
  - adapt persister
     - DONE: persist fragments in /sync
-    - load n items before and after key
-    - fill gaps / fragment filling
+    - DONE: fill gaps / fragment filling
+    - load n items before and after key,
+        - need to add fragments as we come across boundaries
+        - also cache fragments? not for now ...
+        - not doing any of the above, just reloading and rebuilding for now
+
+ - adapt Timeline
+    - turn ObservableArray into ObservableSortedArray
+        - upsert already sorted sections
+        - upsert single entry
+ - adapt TilesCollection & Tile to entry changes
+ 
  - add live fragment id optimization if we haven't done so already
  - lets try to not have to have the fragmentindex in memory if the timeline isn't loaded
     - could do this by only loading all fragments into index when filling gaps, backpaginating, ... and on persister load only load the last fragment. This wouldn't even need a FragmentIndex?

src/domain/session/room/timeline/TilesCollection.js

@@ -22,6 +22,7 @@ export default class TilesCollection extends BaseObservableList {
         for (let entry of this._entries) {
             if (!currentTile || !currentTile.tryIncludeEntry(entry)) {
                 currentTile = this._tileCreator(entry);
+                // if (currentTile) here?
                 this._tiles.push(currentTile);
             }
         }

src/matrix/room/timeline/FragmentIdComparer.js

@@ -163,7 +163,7 @@ export default class FragmentIdComparer {
 export function tests() {
     return {
         test_1_island_3_fragments(assert) {
-            const index = new FragmentIdIndex([
+            const index = new FragmentIdComparer([
                 {id: 3, previousId: 2},
                 {id: 1, nextId: 2},
                 {id: 2, nextId: 3, previousId: 1},
@@ -180,7 +180,7 @@ export function tests() {
             assert.equal(index.compare(1, 1), 0);
         },
         test_2_island_dont_compare(assert) {
-            const index = new FragmentIdIndex([
+            const index = new FragmentIdComparer([
                 {id: 1},
                 {id: 2},
             ]);
@@ -188,7 +188,7 @@ export function tests() {
             assert.throws(() => index.compare(2, 1));
         },
         test_2_island_compare_internally(assert) {
-            const index = new FragmentIdIndex([
+            const index = new FragmentIdComparer([
                 {id: 1, nextId: 2},
                 {id: 2, previousId: 1},
                 {id: 11, nextId: 12},
@@ -203,12 +203,12 @@ export function tests() {
             assert.throws(() => index.compare(12, 2));
         },
         test_unknown_id(assert) {
-            const index = new FragmentIdIndex([{id: 1}]);
+            const index = new FragmentIdComparer([{id: 1}]);
             assert.throws(() => index.compare(1, 2));
             assert.throws(() => index.compare(2, 1));
         },
         test_rebuild_flushes_old_state(assert) {
-            const index = new FragmentIdIndex([
+            const index = new FragmentIdComparer([
                 {id: 1, nextId: 2},
                 {id: 2, previousId: 1},
             ]);

src/matrix/room/timeline/Timeline.js

@@ -1,6 +1,7 @@
 import { ObservableArray } from "../../../observable/index.js";
 import sortedIndex from "../../../utils/sortedIndex.js";
 import GapPersister from "./persistence/GapPersister.js";
+import TimelineReader from "./persistence/TimelineReader.js";
 
 export default class Timeline {
     constructor({roomId, storage, closeCallback, fragmentIdComparer}) {
@@ -9,6 +10,11 @@ export default class Timeline {
         this._closeCallback = closeCallback;
         this._entriesList = new ObservableArray();
         this._fragmentIdComparer = fragmentIdComparer;
+        this._timelineReader = new TimelineReader({
+            roomId: this._roomId,
+            storage: this._storage,
+            fragmentIdComparer: this._fragmentIdComparer
+        });
     }
 
     /** @package */
@@ -53,6 +59,7 @@ export default class Timeline {
     }
 
     async loadAtTop(amount) {
+        // TODO: use TimelineReader::readFrom here, and insert returned array at location for first and last entry.
         const firstEntry = this._entriesList.at(0);
         if (firstEntry) {
             const txn = await this._storage.readTxn([this._storage.storeNames.timelineEvents]);

src/matrix/room/timeline/persistence/GapPersister.js

@@ -1,14 +1,6 @@
 import EventKey from "../EventKey.js";
 import EventEntry from "../entries/EventEntry.js";
-import {createEventEntry} from "./common.js";
-
-function directionalAppend(array, value, direction) {
-    if (direction.isForward) {
-        array.push(value);
-    } else {
-        array.splice(0, 0, value);
-    }
-}
+import {createEventEntry, directionalAppend} from "./common.js";
 
 export default class GapPersister {
     constructor({roomId, storage, fragmentIdComparer}) {

src/matrix/room/timeline/persistence/SyncPersister.js

@@ -11,7 +11,7 @@ export default class SyncPersister {
     }
 
     async load(txn) {
-        const liveFragment = await txn.roomFragments.liveFragment(this._roomId);
+        const liveFragment = await txn.timelineFragments.liveFragment(this._roomId);
         if (liveFragment) {
             const [lastEvent] = await txn.roomTimeline.lastEvents(this._roomId, liveFragment.id, 1);
             // sorting and identifying (e.g. sort key and pk to insert) are a bit intertwined here
@@ -26,7 +26,7 @@ export default class SyncPersister {
     }
 
     async _createLiveFragment(txn, previousToken) {
-        const liveFragment = await txn.roomFragments.liveFragment(this._roomId);
+        const liveFragment = await txn.timelineFragments.liveFragment(this._roomId);
         if (!liveFragment) {
             if (!previousToken) {
                 previousToken = null;
@@ -39,7 +39,7 @@ export default class SyncPersister {
                 previousToken: previousToken,
                 nextToken: null
             };
-            txn.roomFragments.add(fragment);
+            txn.timelineFragments.add(fragment);
             return fragment;
         } else {
             return liveFragment;
@@ -47,12 +47,12 @@ export default class SyncPersister {
     }
 
     async _replaceLiveFragment(oldFragmentId, newFragmentId, previousToken, txn) {
-        const oldFragment = await txn.roomFragments.get(oldFragmentId);
+        const oldFragment = await txn.timelineFragments.get(oldFragmentId);
         if (!oldFragment) {
             throw new Error(`old live fragment doesn't exist: ${oldFragmentId}`);
         }
         oldFragment.nextId = newFragmentId;
-        txn.roomFragments.update(oldFragment);
+        txn.timelineFragments.update(oldFragment);
         const newFragment = {
             roomId: this._roomId,
             id: newFragmentId,
@@ -61,7 +61,7 @@ export default class SyncPersister {
             previousToken: previousToken,
             nextToken: null
         };
-        txn.roomFragments.add(newFragment);
+        txn.timelineFragments.add(newFragment);
         return {oldFragment, newFragment};
     }
 
@@ -117,6 +117,11 @@ export default class SyncPersister {
             }
         }
 
+        if (timeline.limited) {
+            const fragments = await txn.timelineFragments.all(this._roomId);
+            this._fragmentIdComparer.rebuild(fragments);
+        }
+
         return entries;
     }
 }

src/matrix/room/timeline/persistence/TimelineReader.js

@@ -0,0 +1,63 @@
+import {directionalConcat, directionalAppend} from "./common.js";
+import EventKey from "../EventKey.js";
+import EventEntry from "../entries/EventEntry.js";
+import FragmentBoundaryEntry from "../entries/FragmentBoundaryEntry.js";
+
+export default class TimelineReader {
+    constructor({roomId, storage, fragmentIdComparer}) {
+        this._roomId = roomId;
+        this._storage = storage;
+        this._fragmentIdComparer = fragmentIdComparer;
+    }
+
+    async readFrom(eventKey, direction, amount) {
+        const txn = this._storage.readTxn([
+            this._storage.storeNames.timelineEvents,
+            this._storage.storeNames.timelineFragments,
+        ]);
+        let entries = [];
+        let loadedFragment = false;
+
+        const timelineStore = txn.timelineEvents;
+        const fragmentStore = txn.timelineFragments;
+        
+        while (entries.length < amount && eventKey) {
+            let eventsWithinFragment;
+            if (direction.isForward) {
+                eventsWithinFragment = timelineStore.eventsAfter(eventKey, amount);
+            } else {
+                eventsWithinFragment = timelineStore.eventsBefore(eventKey, amount);
+            }
+            const eventEntries = eventsWithinFragment.map(e => new EventEntry(e, this._fragmentIdComparer));
+            entries = directionalConcat(entries, eventEntries, direction);
+            // prepend or append eventsWithinFragment to entries, and wrap them in EventEntry
+
+            if (entries.length < amount) {
+                const fragment = await fragmentStore.get(this._roomId, eventKey.fragmentId);
+                // this._fragmentIdComparer.addFragment(fragment);
+                let fragmentEntry = new FragmentBoundaryEntry(fragment, direction.isBackward, this._fragmentIdComparer);
+                // append or prepend fragmentEntry, reuse func from GapPersister?
+                directionalAppend(entries, fragmentEntry, direction);
+                // don't count it in amount perhaps? or do?
+                if (fragmentEntry.linkedFragmentId) {
+                    const nextFragment = await fragmentStore.get(this._roomId, fragmentEntry.linkedFragmentId);
+                    // this._fragmentIdComparer.addFragment(nextFragment);
+                    const nextFragmentEntry = new FragmentBoundaryEntry(nextFragment, direction.isForward, this._fragmentIdComparer);
+                    directionalAppend(entries, nextFragmentEntry, direction);
+                    eventKey = new EventKey(nextFragmentEntry.fragmentId, nextFragmentEntry.eventIndex);
+                    loadedFragment = true;
+                } else {
+                    eventKey = null;
+                }
+            }
+        }
+
+        // reload fragments
+        if (loadedFragment) {
+            const fragments = await fragmentStore.all(this._roomId);
+            this._fragmentIdComparer.rebuild(fragments);
+        }
+
+        return entries;
+    }
+}

src/matrix/room/timeline/persistence/common.js

@@ -4,4 +4,20 @@ export function createEventEntry(key, event) {
         eventIndex: key.eventIndex,
         event: event,
     };
-}
+}
+
+export function directionalAppend(array, value, direction) {
+    if (direction.isForward) {
+        array.push(value);
+    } else {
+        array.unshift(value);
+    }
+}
+
+export function directionalConcat(array, otherArray, direction) {
+    if (direction.isForward) {
+        return array.concat(otherArray);
+    } else {
+        return otherArray.concat(array);
+    }
+}

src/matrix/session.js

@@ -18,6 +18,7 @@ export default class Session {
             this._storage.storeNames.roomSummary,
             this._storage.storeNames.roomState,
             this._storage.storeNames.timelineEvents,
+            this._storage.storeNames.timelineFragments,
         ]);
         // restore session object
         this._session = await txn.session.get();

src/matrix/sync.js

@@ -74,6 +74,7 @@ export default class Sync extends EventEmitter {
             storeNames.session,
             storeNames.roomSummary,
             storeNames.timelineEvents,
+            storeNames.timelineFragments,
             storeNames.roomState,
         ]);
         const roomChanges = [];

src/observable/list/SortedArray.js

@@ -0,0 +1,38 @@
+import BaseObservableList from "./BaseObservableList.js";
+import sortedIndex from "../../utils/sortedIndex";
+
+export default class SortedArray extends BaseObservableList {
+    constructor(comparator) {
+        super();
+        this._comparator = comparator;
+        this._items = [];
+    }
+
+    setSortedMany(items) {
+
+    }
+
+    set(item) {
+        const idx = sortedIndex(this._items, item, this._comparator);
+        if (idx < this._items.length || this._comparator(this._items[idx], item) !== 0) {
+            this._items.splice(idx, 0, item);
+            //emitAdd
+        } else {
+            this._items[idx] = item;
+            //emitRemove
+            //emitAdd
+        }
+    }
+
+    get array() {
+        return this._items;
+    }
+
+    get length() {
+        return this._items.length;
+    }
+
+    [Symbol.iterator]() {
+        return this._items.values();
+    }
+}