Change the type of tile id key to string (mapbox#8979)

* Change tile id key type from number to string

Author: mpulkki-mapbox

src/geo/transform.js

@@ -50,8 +50,8 @@ class Transform {
     _maxPitch: number;
     _center: LngLat;
     _constraining: boolean;
-    _posMatrixCache: {[number]: Float32Array};
-    _alignedPosMatrixCache: {[number]: Float32Array};
+    _posMatrixCache: {[string]: Float32Array};
+    _alignedPosMatrixCache: {[string]: Float32Array};
 
     constructor(minZoom: ?number, maxZoom: ?number, minPitch: ?number, maxPitch: ?number, renderWorldCopies: boolean | void) {
         this.tileSize = 512; // constant

src/render/painter.js

@@ -103,7 +103,7 @@ class Painter {
     viewportSegments: SegmentVector;
     quadTriangleIndexBuffer: IndexBuffer;
     tileBorderIndexBuffer: IndexBuffer;
-    _tileClippingMaskIDs: { [number]: number };
+    _tileClippingMaskIDs: { [string]: number };
     stencilClearMode: StencilMode;
     style: Style;
     options: PainterOptions;

src/source/source_cache.js

@@ -44,19 +44,20 @@ class SourceCache extends Evented {
     _source: Source;
     _sourceLoaded: boolean;
     _sourceErrored: boolean;
-    _tiles: {[any]: Tile};
+    _tiles: {[string]: Tile};
     _prevLng: number | void;
     _cache: TileCache;
     _timers: {[any]: TimeoutID};
     _cacheTimers: {[any]: TimeoutID};
     _maxTileCacheSize: ?number;
     _paused: boolean;
     _shouldReloadOnResume: boolean;
-    _coveredTiles: {[any]: boolean};
+    _coveredTiles: {[string]: boolean};
     transform: Transform;
-    _isIdRenderable: (id: number, symbolLayer?: boolean) => boolean;
+    _isIdRenderable: (id: string, symbolLayer?: boolean) => boolean;
     used: boolean;
     _state: SourceFeatureState;
+    _loadedParentTiles: {[string]: ?Tile};
 
     static maxUnderzooming: number;
     static maxOverzooming: number;
@@ -93,6 +94,7 @@ class SourceCache extends Evented {
         this._timers = {};
         this._cacheTimers = {};
         this._maxTileCacheSize = null;
+        this._loadedParentTiles = {};
 
         this._coveredTiles = {};
         this._state = new SourceFeatureState();
@@ -179,25 +181,25 @@ class SourceCache extends Evented {
     /**
      * Return all tile ids ordered with z-order, and cast to numbers
      */
-    getIds(): Array<number> {
-        return Object.keys(this._tiles).map(Number).sort(compareKeyZoom);
+    getIds(): Array<string> {
+        return (Object.values(this._tiles): any).map((tile: Tile) => tile.tileID).sort(compareTileId).map(id => id.key);
     }
 
-    getRenderableIds(symbolLayer?: boolean): Array<number> {
-        const ids = [];
+    getRenderableIds(symbolLayer?: boolean): Array<string> {
+        const renderables: Array<Tile> = [];
         for (const id in this._tiles) {
-            if (this._isIdRenderable(+id, symbolLayer)) ids.push(+id);
+            if (this._isIdRenderable(id, symbolLayer)) renderables.push(this._tiles[id]);
         }
         if (symbolLayer) {
-            return ids.sort((a_, b_) => {
-                const a = this._tiles[a_].tileID;
-                const b = this._tiles[b_].tileID;
+            return renderables.sort((a_: Tile, b_: Tile) => {
+                const a = a_.tileID;
+                const b = b_.tileID;
                 const rotatedA = (new Point(a.canonical.x, a.canonical.y))._rotate(this.transform.angle);
                 const rotatedB = (new Point(b.canonical.x, b.canonical.y))._rotate(this.transform.angle);
                 return a.overscaledZ - b.overscaledZ || rotatedB.y - rotatedA.y || rotatedB.x - rotatedA.x;
-            });
+            }).map(tile => tile.tileID.key);
         }
-        return ids.sort(compareKeyZoom);
+        return renderables.map(tile => tile.tileID).sort(compareTileId).map(id => id.key);
     }
 
     hasRenderableParent(tileID: OverscaledTileID) {
@@ -208,7 +210,7 @@ class SourceCache extends Evented {
         return false;
     }
 
-    _isIdRenderable(id: number, symbolLayer?: boolean) {
+    _isIdRenderable(id: string, symbolLayer?: boolean) {
         return this._tiles[id] && this._tiles[id].hasData() &&
             !this._coveredTiles[id] && (symbolLayer || !this._tiles[id].holdingForFade());
     }
@@ -226,7 +228,7 @@ class SourceCache extends Evented {
         }
     }
 
-    _reloadTile(id: string | number, state: TileState) {
+    _reloadTile(id: string, state: TileState) {
         const tile = this._tiles[id];
 
         // this potentially does not address all underlying
@@ -245,7 +247,7 @@ class SourceCache extends Evented {
         this._loadTile(tile, this._tileLoaded.bind(this, tile, id, state));
     }
 
-    _tileLoaded(tile: Tile, id: string | number, previousState: TileState, err: ?Error) {
+    _tileLoaded(tile: Tile, id: string, previousState: TileState, err: ?Error) {
         if (err) {
             tile.state = 'errored';
             if ((err: any).status !== 404) this._source.fire(new ErrorEvent(err, {tile}));
@@ -313,7 +315,7 @@ class SourceCache extends Evented {
     /**
      * Get a specific tile by id
      */
-    getTileByID(id: string | number): Tile {
+    getTileByID(id: string): Tile {
         return this._tiles[id];
     }
 
@@ -367,19 +369,33 @@ class SourceCache extends Evented {
      * Find a loaded parent of the given tile (up to minCoveringZoom)
      */
     findLoadedParent(tileID: OverscaledTileID, minCoveringZoom: number): ?Tile {
+        if (tileID.key in this._loadedParentTiles) {
+            const parent = this._loadedParentTiles[tileID.key];
+            if (parent && parent.tileID.overscaledZ >= minCoveringZoom) {
+                return parent;
+            } else {
+                return null;
+            }
+        }
         for (let z = tileID.overscaledZ - 1; z >= minCoveringZoom; z--) {
-            const parentKey = tileID.calculateScaledKey(z, true);
-            const tile = this._tiles[parentKey];
-            if (tile && tile.hasData()) {
+            const parentTileID = tileID.scaledTo(z);
+            const tile = this._getLoadedTile(parentTileID);
+            if (tile) {
                 return tile;
             }
-            // TileCache ignores wrap in lookup.
-            const parentWrappedKey = tileID.calculateScaledKey(z, false);
-            const cachedTile = this._cache.getByKey(parentWrappedKey);
-            if (cachedTile) return cachedTile;
         }
     }
 
+    _getLoadedTile(tileID: OverscaledTileID): ?Tile {
+        const tile = this._tiles[tileID.key];
+        if (tile && tile.hasData()) {
+            return tile;
+        }
+        // TileCache ignores wrap in lookup.
+        const cachedTile = this._cache.getByKey(tileID.wrapped().key);
+        return cachedTile;
+    }
+
     /**
      * Resizes the tile cache based on the current viewport's size
      * or the maxTileCacheSize option passed during map creation
@@ -423,7 +439,7 @@ class SourceCache extends Evented {
         this._prevLng = lng;
 
         if (wrapDelta) {
-            const tiles = {};
+            const tiles: {[string]: Tile} = {};
             for (const key in this._tiles) {
                 const tile = this._tiles[key];
                 tile.tileID = tile.tileID.unwrapTo(tile.tileID.wrap + wrapDelta);
@@ -489,12 +505,12 @@ class SourceCache extends Evented {
         const retain = this._updateRetainedTiles(idealTileIDs, zoom);
 
         if (isRasterType(this._source.type)) {
-            const parentsForFading = {};
+            const parentsForFading: {[string]: OverscaledTileID} = {};
             const fadingTiles = {};
             const ids = Object.keys(retain);
             for (const id of ids) {
                 const tileID = retain[id];
-                assert(tileID.key === +id);
+                assert(tileID.key === id);
 
                 const tile = this._tiles[id];
                 if (!tile || tile.fadeEndTime && tile.fadeEndTime <= browser.now()) continue;
@@ -537,6 +553,9 @@ class SourceCache extends Evented {
                 this._removeTile(tileID);
             }
         }
+
+        // Construct a cache of loaded parents
+        this._updateLoadedParentTileCache();
     }
 
     releaseSymbolFadeTiles() {
@@ -548,8 +567,8 @@ class SourceCache extends Evented {
     }
 
     _updateRetainedTiles(idealTileIDs: Array<OverscaledTileID>, zoom: number): { [string]: OverscaledTileID} {
-        const retain = {};
-        const checked: {[number]: boolean } = {};
+        const retain: {[string]: OverscaledTileID} = {};
+        const checked: {[string]: boolean } = {};
         const minCoveringZoom = Math.max(zoom - SourceCache.maxOverzooming, this._source.minzoom);
         const maxCoveringZoom = Math.max(zoom + SourceCache.maxUnderzooming,  this._source.minzoom);
 
@@ -628,6 +647,43 @@ class SourceCache extends Evented {
         return retain;
     }
 
+    _updateLoadedParentTileCache() {
+        this._loadedParentTiles = {};
+
+        for (const tileKey in this._tiles) {
+            const path = [];
+            let parentTile: ?Tile;
+            let currentId = this._tiles[tileKey].tileID;
+
+            // Find the closest loaded ancestor by traversing the tile tree towards the root and
+            // caching results along the way
+            while (currentId.overscaledZ > 0) {
+
+                // Do we have a cached result from previous traversals?
+                if (currentId.key in this._loadedParentTiles) {
+                    parentTile = this._loadedParentTiles[currentId.key];
+                    break;
+                }
+
+                path.push(currentId.key);
+
+                // Is the parent loaded?
+                const parentId = currentId.scaledTo(currentId.overscaledZ - 1);
+                parentTile = this._getLoadedTile(parentId);
+                if (parentTile) {
+                    break;
+                }
+
+                currentId = parentId;
+            }
+
+            // Cache the result of this traversal to all newly visited tiles
+            for (const key of path) {
+                this._loadedParentTiles[key] = parentTile;
+            }
+        }
+    }
+
     /**
      * Add a tile, given its coordinate, to the pyramid.
      * @private
@@ -666,7 +722,7 @@ class SourceCache extends Evented {
         return tile;
     }
 
-    _setTileReloadTimer(id: string | number, tile: Tile) {
+    _setTileReloadTimer(id: string, tile: Tile) {
         if (id in this._timers) {
             clearTimeout(this._timers[id]);
             delete this._timers[id];
@@ -685,7 +741,7 @@ class SourceCache extends Evented {
      * Remove a tile, given its id, from the pyramid
      * @private
      */
-    _removeTile(id: string | number) {
+    _removeTile(id: string) {
         const tile = this._tiles[id];
         if (!tile)
             return;
@@ -846,7 +902,7 @@ class SourceCache extends Evented {
      * Sets the set of keys that the tile depends on. This allows tiles to
      * be reloaded when their dependencies change.
      */
-    setDependencies(tileKey: string | number, namespace: string, dependencies: Array<string>) {
+    setDependencies(tileKey: string, namespace: string, dependencies: Array<string>) {
         const tile = this._tiles[tileKey];
         if (tile) {
             tile.setDependencies(namespace, dependencies);
@@ -870,8 +926,13 @@ class SourceCache extends Evented {
 SourceCache.maxOverzooming = 10;
 SourceCache.maxUnderzooming = 3;
 
-function compareKeyZoom(a, b) {
-    return ((a % 32) - (b % 32)) || (b - a);
+function compareTileId(a: OverscaledTileID, b: OverscaledTileID): number {
+    // Different copies of the world are sorted based on their distance to the center.
+    // Wrap values are converted to unsigned distances by reserving odd number for copies
+    // with negative wrap and even numbers for copies with positive wrap.
+    const aWrap = Math.abs(a.wrap * 2) - +(a.wrap < 0);
+    const bWrap = Math.abs(b.wrap * 2) - +(b.wrap < 0);
+    return a.overscaledZ - b.overscaledZ || bWrap - aWrap || b.canonical.y - a.canonical.y || b.canonical.x - a.canonical.x;
 }
 
 function isRasterType(type) {

src/source/tile_cache.js

@@ -12,8 +12,8 @@ import type Tile from './tile';
  */
 class TileCache {
     max: number;
-    data: {[key: number | string]: Array<{ value: Tile, timeout: ?TimeoutID}>};
-    order: Array<number>;
+    data: {[key: string]: Array<{ value: Tile, timeout: ?TimeoutID}>};
+    order: Array<string>;
     onRemove: (element: Tile) => void;
     /**
      * @param {number} max number of permitted values
@@ -110,7 +110,7 @@ class TileCache {
     /*
      * Get and remove the value with the specified key.
      */
-    _getAndRemoveByKey(key: number): ?Tile {
+    _getAndRemoveByKey(key: string): ?Tile {
         const data = this.data[key].shift();
         if (data.timeout) clearTimeout(data.timeout);
 
@@ -125,7 +125,7 @@ class TileCache {
     /*
      * Get the value with the specified (wrapped tile) key.
      */
-    getByKey(key: number): ?Tile {
+    getByKey(key: string): ?Tile {
         const data = this.data[key];
         return data ? data[0].value : null;
     }