Support prioritized room list filters

src/stores/room-list/algorithms/list-ordering/Algorithm.ts

@@ -20,9 +20,11 @@ import { isNullOrUndefined } from "matrix-js-sdk/src/utils";
 import { EffectiveMembership, splitRoomsByMembership } from "../../membership";
 import { ITagMap, ITagSortingMap } from "../models";
 import DMRoomMap from "../../../../utils/DMRoomMap";
-import { FILTER_CHANGED, IFilterCondition } from "../../filters/IFilterCondition";
+import { FILTER_CHANGED, FilterPriority, IFilterCondition } from "../../filters/IFilterCondition";
 import { EventEmitter } from "events";
 import { UPDATE_EVENT } from "../../../AsyncStore";
+import { ArrayUtil } from "../../../../utils/arrays";
+import { getEnumValues } from "../../../../utils/enums";
 
 // TODO: Add locking support to avoid concurrent writes?
 
@@ -184,30 +186,42 @@ export abstract class Algorithm extends EventEmitter {
         }
 
         console.warn("Recalculating filtered room list");
-        const allowedByFilters = new Set<Room>();
         const filters = Array.from(this.allowedByFilter.keys());
+        const orderedFilters = new ArrayUtil(filters)
+            .groupBy(f => f.relativePriority)
+            .orderBy(getEnumValues(FilterPriority))
+            .value;
         const newMap: ITagMap = {};
         for (const tagId of Object.keys(this.cachedRooms)) {
             // Cheaply clone the rooms so we can more easily do operations on the list.
             // We optimize our lookups by trying to reduce sample size as much as possible
             // to the rooms we know will be deduped by the Set.
             const rooms = this.cachedRooms[tagId];
-            const remainingRooms = rooms.map(r => r).filter(r => !allowedByFilters.has(r));
-            const allowedRoomsInThisTag = [];
-            for (const filter of filters) {
+            let remainingRooms = rooms.map(r => r);
+            let allowedRoomsInThisTag = [];
+            let lastFilterPriority = orderedFilters[0].relativePriority;
+            for (const filter of orderedFilters) {
+                if (filter.relativePriority !== lastFilterPriority) {
+                    // Every time the filter changes priority, we want more specific filtering.
+                    // To accomplish that, reset the variables to make it look like the process
+                    // has started over, but using the filtered rooms as the seed.
+                    remainingRooms = allowedRoomsInThisTag;
+                    allowedRoomsInThisTag = [];
+                    lastFilterPriority = filter.relativePriority;
+                }
                 const filteredRooms = remainingRooms.filter(r => filter.isVisible(r));
                 for (const room of filteredRooms) {
                     const idx = remainingRooms.indexOf(room);
                     if (idx >= 0) remainingRooms.splice(idx, 1);
-                    allowedByFilters.add(room);
                     allowedRoomsInThisTag.push(room);
                 }
             }
             newMap[tagId] = allowedRoomsInThisTag;
             console.log(`[DEBUG] ${newMap[tagId].length}/${rooms.length} rooms filtered into ${tagId}`);
         }
 
-        this.allowedRoomsByFilters = allowedByFilters;
+        const allowedRooms = Object.values(newMap).reduce((rv, v) => { rv.push(...v); return rv; }, <Room[]>[]);
+        this.allowedRoomsByFilters = new Set(allowedRooms);
         this.filteredRooms = newMap;
         this.emit(LIST_UPDATED_EVENT);
     }

src/stores/room-list/filters/CommunityFilterCondition.ts

@@ -15,7 +15,7 @@ limitations under the License.
 */
 
 import { Room } from "matrix-js-sdk/src/models/room";
-import { FILTER_CHANGED, IFilterCondition } from "./IFilterCondition";
+import { FILTER_CHANGED, FilterPriority, IFilterCondition } from "./IFilterCondition";
 import { Group } from "matrix-js-sdk/src/models/group";
 import { EventEmitter } from "events";
 import GroupStore from "../../GroupStore";
@@ -37,6 +37,11 @@ export class CommunityFilterCondition extends EventEmitter implements IFilterCon
         this.onStoreUpdate(); // trigger a false update to seed the store
     }
 
+    public get relativePriority(): FilterPriority {
+        // Lowest priority so we can coarsely find rooms.
+        return FilterPriority.Lowest;
+    }
+
     public isVisible(room: Room): boolean {
         return this.roomIds.includes(room.roomId);
     }

src/stores/room-list/filters/IFilterCondition.ts

@@ -19,6 +19,12 @@ import { EventEmitter } from "events";
 
 export const FILTER_CHANGED = "filter_changed";
 
+export enum FilterPriority {
+    Lowest,
+    // in the middle would be Low, Normal, and High if we had a need
+    Highest,
+}
+
 /**
  * A filter condition for the room list, determining if a room
  * should be shown or not.
@@ -32,6 +38,12 @@ export const FILTER_CHANGED = "filter_changed";
  * as a change in the user's input), this emits FILTER_CHANGED.
  */
 export interface IFilterCondition extends EventEmitter {
+    /**
+     * The relative priority that this filter should be applied with.
+     * Lower priorities get applied first.
+     */
+    relativePriority: FilterPriority;
+
     /**
      * Determines if a given room should be visible under this
      * condition.

src/stores/room-list/filters/NameFilterCondition.ts

@@ -15,7 +15,7 @@ limitations under the License.
 */
 
 import { Room } from "matrix-js-sdk/src/models/room";
-import { FILTER_CHANGED, IFilterCondition } from "./IFilterCondition";
+import { FILTER_CHANGED, FilterPriority, IFilterCondition } from "./IFilterCondition";
 import { EventEmitter } from "events";
 
 /**
@@ -29,6 +29,11 @@ export class NameFilterCondition extends EventEmitter implements IFilterConditio
         super();
     }
 
+    public get relativePriority(): FilterPriority {
+        // We want this one to be at the highest priority so it can search within other filters.
+        return FilterPriority.Highest;
+    }
+
     public get search(): string {
         return this._search;
     }

src/utils/arrays.ts

@@ -45,3 +45,63 @@ export function arrayDiff<T>(a: T[], b: T[]): { added: T[], removed: T[] } {
         removed: a.filter(i => !b.includes(i)),
     };
 }
+
+/**
+ * Helper functions to perform LINQ-like queries on arrays.
+ */
+export class ArrayUtil<T> {
+    /**
+     * Create a new array helper.
+     * @param a The array to help. Can be modified in-place.
+     */
+    constructor(private a: T[]) {
+    }
+
+    /**
+     * The value of this array, after all appropriate alterations.
+     */
+    public get value(): T[] {
+        return this.a;
+    }
+
+    /**
+     * Groups an array by keys.
+     * @param fn The key-finding function.
+     * @returns This.
+     */
+    public groupBy<K>(fn: (a: T) => K): GroupedArray<K, T> {
+        const obj = this.a.reduce((rv: Map<K, T[]>, val: T) => {
+            const k = fn(val);
+            if (!rv.has(k)) rv.set(k, []);
+            rv.get(k).push(val);
+            return rv;
+        }, new Map<K, T[]>());
+        return new GroupedArray(obj);
+    }
+}
+
+/**
+ * Helper functions to perform LINQ-like queries on groups (maps).
+ */
+export class GroupedArray<K, T> {
+    /**
+     * Creates a new group helper.
+     * @param val The group to help. Can be modified in-place.
+     */
+    constructor(private val: Map<K, T[]>) {
+    }
+
+    /**
+     * Orders the grouping into an array using the provided key order.
+     * @param keyOrder The key order.
+     * @returns An array helper of the result.
+     */
+    public orderBy(keyOrder: K[]): ArrayUtil<T> {
+        const a: T[] = [];
+        for (const k of keyOrder) {
+            if (!this.val.has(k)) continue;
+            a.push(...this.val.get(k));
+        }
+        return new ArrayUtil(a);
+    }
+}

src/utils/enums.ts

@@ -0,0 +1,27 @@
+/*
+Copyright 2020 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+/**
+ * Get the values for an enum.
+ * @param e The enum.
+ * @returns The enum values.
+ */
+export function getEnumValues<T>(e: any): T[] {
+    const keys = Object.keys(e);
+    return keys
+        .filter(k => ['string', 'number'].includes(typeof(e[k])))
+        .map(k => e[k]);
+}