Improve, optimize, and consolidate Tile LRU cache to new ES6 Map

src/source/vector_tile_worker_source.ts

@@ -2,7 +2,7 @@ import Protobuf from 'pbf';
 import {VectorTile} from '@mapbox/vector-tile';
 import {type ExpiryData, getArrayBuffer} from '../util/ajax';
 import {WorkerTile} from './worker_tile';
-import {BoundedLRUCache} from '../tile/tile_cache';
+import {BoundedLRUCache} from '../tile/bounded_lru_cache';
 import {extend} from '../util/util';
 import {RequestPerformance} from '../util/performance';
 import {VectorTileOverzoomed, sliceVectorTileLayer, toVirtualVectorTile} from './vector_tile_overzoomed';
@@ -61,7 +61,7 @@ export class VectorTileWorkerSource implements WorkerSource {
         this.fetching = {};
         this.loading = {};
         this.loaded = {};
-        this.overzoomedTileResultCache = new BoundedLRUCache<string, LoadVectorTileResult>(1000);
+        this.overzoomedTileResultCache = new BoundedLRUCache<string, LoadVectorTileResult>({maxEntries: 1000});
     }
 
     /**
@@ -70,8 +70,8 @@ export class VectorTileWorkerSource implements WorkerSource {
     async loadVectorTile(params: WorkerTileParameters, abortController: AbortController): Promise<LoadVectorTileResult> {
         const response = await getArrayBuffer(params.request, abortController);
         try {
-            const vectorTile = params.encoding !== 'mlt' 
-                ? new VectorTile(new Protobuf(response.data)) 
+            const vectorTile = params.encoding !== 'mlt'
+                ? new VectorTile(new Protobuf(response.data))
                 : new MLTVectorTile(response.data);
             return {
                 vectorTile,
@@ -172,7 +172,7 @@ export class VectorTileWorkerSource implements WorkerSource {
 
         const cacheKey = `${maxZoomTileID.key}_${tileID.key}`;
         const cachedOverzoomTile = this.overzoomedTileResultCache.get(cacheKey);
-        
+
         if (cachedOverzoomTile) {
             return cachedOverzoomTile;
         }

src/tile/bounded_lru_cache.test.ts

@@ -0,0 +1,336 @@
+import {describe, test, expect} from 'vitest';
+import {type Tile} from './tile';
+import {BoundedLRUCache} from './bounded_lru_cache';
+import {OverscaledTileID} from './tile_id';
+
+const _idA = new OverscaledTileID(10, 0, 10, 0, 1);
+const _idB = new OverscaledTileID(10, 0, 10, 0, 2);
+const _idC = new OverscaledTileID(10, 0, 10, 0, 3);
+const _idD = new OverscaledTileID(10, 0, 10, 0, 4);
+const idA = _idA.key;
+const idB = _idB.key;
+const idC = _idC.key;
+const idD = _idD.key;
+const tileA = {tileID: _idA} as Tile;
+const tileA2 = {tileID: _idA} as Tile;
+const tileB = {tileID: _idB} as Tile;
+const tileC = {tileID: _idC} as Tile;
+const tileD = {tileID: _idD} as Tile;
+
+function keysExpected(cache: BoundedLRUCache<string, Tile>, ids: string[]): void {
+    expect(cache.getKeys()).toEqual(ids);
+}
+
+describe('BoundedLRUCache', () => {
+    test('complex flow', () => {
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+            onRemove: (removed) => expect(removed).toBe(idC)
+        });
+        expect(cache.take(idC)).toBeUndefined();
+        cache.set(idA, tileA);
+        keysExpected(cache, [idA]);
+        expect(cache.get(idA)).toBe(tileA);
+        expect(cache.take(idA)).toBe(tileA);
+        expect(cache.take(idA)).toBeUndefined();
+        expect(cache.get(idA)).toBe(undefined);
+        keysExpected(cache, []);
+    });
+
+    test('get', () => {
+        let removeCount = 0;
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+            onRemove: () => removeCount++
+        });
+        cache.set(idA, tileA);
+        expect(cache.get(idA)).toBe(tileA);
+        keysExpected(cache, [idA]);
+        expect(cache.get(idA)).toBe(tileA);
+        expect(removeCount).toBe(0);
+    });
+
+    test('get re-ordering and getKeys order', () => {
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+        });
+        cache.set(idA, tileA);
+        cache.set(idB, tileB);
+        cache.set(idC, tileC);
+        expect(cache.getKeys()).toEqual([idA, idB, idC]);
+        expect(cache.get(idA)).toBe(tileA);
+        expect(cache.getKeys()).toEqual([idB, idC, idA]);
+    });
+
+    test('take without calling onRemove', () => {
+        let removeCount = 0;
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+            onRemove: () => removeCount++
+        });
+        cache.set(idA, tileA);
+        keysExpected(cache, [idA]);
+
+        const tile = cache.take(idA);
+        expect(tile).toBe(tileA);
+        expect(cache.get(idA)).toBeUndefined();
+        keysExpected(cache, []);
+        expect(removeCount).toBe(0);
+    });
+
+    test('remove tile calls onRemove', () => {
+        let removeCount = 0;
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+            onRemove: () => removeCount++
+        });
+        cache.set(idA, tileA);
+        cache.remove(idA);
+        expect(removeCount).toBe(1);
+    });
+
+    test('duplicate add', () => {
+        let removeCount = 0;
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+            onRemove: () => removeCount++
+        });
+        cache.set(idA, tileA);
+        cache.set(idA, tileA2);
+
+        keysExpected(cache, [idA]);
+        expect(cache.get(idA)).toBe(tileA2);
+        expect(cache.take(idA)).toBe(tileA2);
+        expect(cache.get(idA)).toBeUndefined();
+        expect(cache.take(idA)).toBeUndefined();
+        keysExpected(cache, []);
+        expect(removeCount).toBe(1);
+    });
+
+    test('set of same tile id using the same tile retains tile and moves to end without calling remove', () => {
+        let removeCount = 0;
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+            onRemove: () => removeCount++
+        });
+        cache.set(idA, tileA);
+        cache.set(idB, tileB);
+        keysExpected(cache, [idA, idB]);
+
+        // Set the same tile reference again, but it should not call remove.
+        cache.set(idA, tileA);
+        expect(removeCount).toBe(0);
+        keysExpected(cache, [idB, idA]);
+        expect(cache.get(idA)).toBe(tileA);
+    });
+
+    test('set of same tile id using a new tile removes previous tile reference and calls remove', () => {
+        let removeCount = 0;
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+            onRemove: () => removeCount++
+
+        });
+        cache.set(idA, tileA);
+        cache.set(idB, tileB);
+        keysExpected(cache, [idA, idB]);
+
+        // Set the same tile id but with new tile, remove should be called
+        cache.set(idA, tileA2);
+        expect(removeCount).toBe(1);
+        keysExpected(cache, [idB, idA]);
+        expect(cache.get(idA)).toBe(tileA2);
+    });
+
+    test('duplicate set of same tile id updates entry to most recently added tile', () => {
+        const cache = new BoundedLRUCache<string, Tile>({maxEntries: 10});
+        cache.set(idA, tileA);
+        cache.set(idA, tileA2);
+
+        keysExpected(cache, [idA]);
+        expect(cache.get(idA)).toBe(tileA2);
+    });
+
+    test('set of tile over max entries trims the cache', () => {
+        let removeCount = 0;
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 1,
+            onRemove: () => removeCount++
+
+        });
+        cache.set(idA, tileA);
+        cache.set(idB, tileB);
+        keysExpected(cache, [idB]);
+        expect(cache.get(idB)).toBe(tileB);
+
+        cache.set(idA, tileA2);
+        keysExpected(cache, [idA]);
+        expect(cache.get(idA)).toBe(tileA2);
+
+        expect(removeCount).toBe(2);
+    });
+
+    test('removes tiles', () => {
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10
+        });
+
+        cache.set(idA, tileA);
+        cache.set(idB, tileB);
+        cache.set(idC, tileC);
+
+        keysExpected(cache, [idA, idB, idC]);
+        expect(cache.get(idB)).toBe(tileB);
+        cache.remove(idB);
+
+        keysExpected(cache, [idA, idC]);
+        expect(cache.get(idB)).toBeUndefined();
+        expect(() => cache.remove(idB)).not.toThrow();
+    });
+
+    test('filters tiles using provided function', () => {
+        let removeCount = 0;
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+            onRemove: () => removeCount++
+        });
+        cache.set(idA, tileA);
+        cache.set(idB, tileB);
+        cache.set(idC, tileC);
+        cache.set(idD, tileD);
+
+        cache.filter(tile => tile.tileID.canonical.y === 2 || tile.tileID.canonical.y === 3);
+        keysExpected(cache, [idB, idC]);
+        expect(removeCount).toBe(2);
+
+        removeCount = 0;
+        cache.set(idA, tileA);
+        cache.set(idB, tileB);
+        cache.set(idC, tileC);
+        cache.set(idD, tileD);
+        cache.filter(tile => tile.tileID.canonical.y === 1 || tile.tileID.canonical.y === 4);
+        keysExpected(cache, [idA, idD]);
+        expect(removeCount).toBe(2);
+    });
+
+    test('clear tiles call onRemove on all tiles', () => {
+        let removeCount = 0;
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+            onRemove: () => removeCount++
+        });
+
+        cache.set(idA, tileA);
+        cache.set(idB, tileB);
+        cache.set(idC, tileC);
+
+        cache.clear();
+        keysExpected(cache, []);
+        expect(removeCount).toBe(3);
+    });
+
+    test('.clear removes all tiles', () => {
+        let called;
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+            onRemove: (removed) => {
+                expect(removed).toBe(tileA);
+                called = true;
+            }
+        });
+        cache.set(idA, tileA);
+        cache.clear();
+        expect(cache.get(idA)).toBeUndefined();
+        expect(called).toBeTruthy();
+    });
+
+    test('overflow automatically evicts', () => {
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 1,
+            onRemove: (removed) => expect(removed).toBe(tileA)
+        });
+        cache.set(idA, tileA);
+        cache.set(idB, tileB);
+
+        expect(cache.get(idB)).toBeTruthy();
+        expect(cache.get(idA)).toBeFalsy();
+    });
+
+    test('.setMaxSize trims tile count', () => {
+        let numRemoved = 0;
+        const cache = new BoundedLRUCache<string, Tile>({
+            maxEntries: 10,
+            onRemove: () => numRemoved++
+        });
+        cache.set(idA, tileA);
+        cache.set(idB, tileB);
+        cache.set(idC, tileC);
+        expect(numRemoved).toBe(0);
+        cache.setMaxSize(15);
+        expect(numRemoved).toBe(0);
+        cache.setMaxSize(1);
+        expect(numRemoved).toBe(2);
+        keysExpected(cache, [idC]);
+        cache.set(idD, tileD);
+        expect(numRemoved).toBe(3);
+        keysExpected(cache, [idD]);
+    });
+
+    test('evicts least-recently-used item when capacity exceeded', () => {
+        const cache = new BoundedLRUCache<string, number>({maxEntries: 2});
+
+        cache.set('a', 1);
+        cache.set('b', 2);
+
+        // Access 'a' to make it most-recently-used
+        expect(cache.get('a')).toBe(1);
+
+        // Insert 'c' -> should evict 'b' (the least recently used)
+        cache.set('c', 3);
+
+        expect(cache.get('b')).toBeUndefined();
+        expect(cache.get('a')).toBe(1);
+        expect(cache.get('c')).toBe(3);
+    });
+
+    test('setting an existing key updates value and makes it most-recently-used', () => {
+        const cache = new BoundedLRUCache<string, number>({maxEntries: 2});
+
+        cache.set('a', 1);
+        cache.set('b', 2);
+
+        // Update 'a' value and it should become most-recently-used
+        cache.set('a', 10);
+        // Insert 'c' -> should evict 'b'
+        cache.set('c', 3);
+
+        expect(cache.get('b')).toBeUndefined();
+        expect(cache.get('a')).toBe(10);
+        expect(cache.get('c')).toBe(3);
+    });
+
+    test('capacity 1 evicts previous entry on new set', () => {
+        const cache = new BoundedLRUCache<string, string>({maxEntries: 1});
+
+        cache.set('x', 'first');
+        expect(cache.get('x')).toBe('first');
+
+        cache.set('y', 'second');
+        expect(cache.get('x')).toBeUndefined();
+        expect(cache.get('y')).toBe('second');
+    });
+
+    test('clear removes all entries', () => {
+        const cache = new BoundedLRUCache<number, string>({maxEntries: 3});
+        cache.set(1, 'one');
+        cache.set(2, 'two');
+
+        expect(cache.get(1)).toBe('one');
+        expect(cache.get(2)).toBe('two');
+
+        cache.clear();
+
+        expect(cache.get(1)).toBeUndefined();
+        expect(cache.get(2)).toBeUndefined();
+    });
+});