replace tiledata with sourcedata, fire on every tile load (#4347)

* source sorcery ✨

* fix render tests 🎨

* fix unit tests 🔧

* refactor to make everything dependent on 'data' event with new properties

* change language, updates tests

* use sourceDataType event property 📆

* fixy tests ✅

* 'update' 👉 'content', update tests, docs 📝

src/source/canvas_source.js

@@ -75,7 +75,6 @@ class CanvasSource extends ImageSource {
         this.load();
         if (this.canvas) {
             if (this.animate) this.play();
-            this.setCoordinates(this.coordinates);
         }
     }
 

src/source/geojson_source.js

@@ -108,8 +108,9 @@ class GeoJSONSource extends Evented {
                 this.fire('error', {error: err});
                 return;
             }
-            this.fire('data', {dataType: 'source'});
-            this.fire('source.load');
+            // although GeoJSON sources contain no metadata, we fire this event to let the SourceCache
+            // know its ok to start requesting tiles.
+            this.fire('data', {dataType: 'source', sourceDataType: 'metadata'});
         });
     }
 
@@ -126,13 +127,12 @@ class GeoJSONSource extends Evented {
      */
     setData(data) {
         this._data = data;
-
         this.fire('dataloading', {dataType: 'source'});
         this._updateWorkerData((err) => {
             if (err) {
                 return this.fire('error', { error: err });
             }
-            this.fire('data', {dataType: 'source'});
+            this.fire('data', {dataType: 'source', sourceDataType: 'content'});
         });
 
         return this;

src/source/image_source.js

@@ -75,10 +75,9 @@ class ImageSource extends Evented {
     }
 
     _finishLoading() {
-        this.fire('source.load');
-
         if (this.map) {
             this.setCoordinates(this.coordinates);
+            this.fire('data', {dataType: 'source', sourceDataType: 'metadata'});
         }
     }
 
@@ -124,7 +123,7 @@ class ImageSource extends Evented {
                 Math.round((zoomedCoord.row - centerCoord.row) * EXTENT));
         });
 
-        this.fire('data', {dataType: 'source'});
+        this.fire('data', {dataType:'source', sourceDataType: 'content'});
         return this;
     }
 

src/source/raster_tile_source.js

@@ -32,8 +32,13 @@ class RasterTileSource extends Evented {
                 return this.fire('error', err);
             }
             util.extend(this, tileJSON);
-            this.fire('data', {dataType: 'source'});
-            this.fire('source.load');
+
+            // `content` is included here to prevent a race condition where `Style#_updateSources` is called
+            // before the TileJSON arrives. this makes sure the tiles needed are loaded once TileJSON arrives
+            // ref: https://github.com/mapbox/mapbox-gl-js/pull/4347#discussion_r104418088
+            this.fire('data', {dataType: 'source', sourceDataType: 'metadata'});
+            this.fire('data', {dataType: 'source', sourceDataType: 'content'});
+
         });
     }
 

src/source/source.js

@@ -50,8 +50,9 @@ exports.setType = function (name, type) {
  * @param {string} options.type The source type, matching the value of `name` used in {@link Style#addSourceType}.
  * @param {Dispatcher} dispatcher A {@link Dispatcher} instance, which can be used to send messages to the workers.
  *
- * @fires load to indicate source data has been loaded, so that it's okay to call `loadTile`
- * @fires change to indicate source data has changed, so that any current caches should be flushed
+ * @fires data with `{dataType: 'source', sourceDataType: 'metadata'}` to indicate that any necessary metadata
+ * has been loaded so that it's okay to call `loadTile`; and with `{dataType: 'source', sourceDataType: 'content'}`
+ * to indicate that the source data has changed, so that any current caches should be flushed.
  * @property {string} id The id for the source.  Must match the id passed to the constructor.
  * @property {number} minzoom
  * @property {number} maxzoom

src/source/source_cache.js

@@ -27,23 +27,26 @@ class SourceCache extends Evented {
         this.id = id;
         this.dispatcher = dispatcher;
 
-        this.on('source.load', function() {
-            this._sourceLoaded = true;
-        });
-
-        this.on('error', function() {
-            this._sourceErrored = true;
-        });
-
-        this.on('data', function(event) {
-            if (this._sourceLoaded && event.dataType === 'source') {
+        this.on('data', function(e) {
+            // this._sourceLoaded signifies that the TileJSON is loaded if applicable.
+            // if the source type does not come with a TileJSON, the flag signifies the
+            // source data has loaded (i.e geojson has been tiled on the worker and is ready)
+            if (e.dataType === 'source' && e.sourceDataType==='metadata') this._sourceLoaded = true;
+
+            // for sources with mutable data, this event fires when the underlying data
+            // to a source is changed. (i.e. GeoJSONSource#setData and ImageSource#serCoordinates)
+            if (this._sourceLoaded && e.dataType==="source" && e.sourceDataType==='content') {
                 this.reload();
                 if (this.transform) {
                     this.update(this.transform);
                 }
             }
         });
 
+        this.on('error', function() {
+            this._sourceErrored = true;
+        });
+
         this._source = Source.create(id, options, dispatcher, this);
 
         this._tiles = {};
@@ -110,6 +113,7 @@ class SourceCache extends Evented {
         return this._source.serialize();
     }
 
+
     prepare() {
         if (this._sourceLoaded && this._source.prepare)
             return this._source.prepare();
@@ -169,7 +173,7 @@ class SourceCache extends Evented {
         tile.timeAdded = new Date().getTime();
         if (previousState === 'expired') tile.refreshedUponExpiration = true;
         this._setTileReloadTimer(id, tile);
-        this._source.fire('data', {tile: tile, coord: tile.coord, dataType: 'tile'});
+        this._source.fire('data', {dataType: 'source', tile: tile, coord: tile.coord});
 
         // HACK this is necessary to fix https://github.com/mapbox/mapbox-gl-js/issues/2986
         if (this.map) this.map.painter.tileExtentVAO.vao = null;
@@ -296,6 +300,7 @@ class SourceCache extends Evented {
      * @private
      */
     update(transform) {
+        this.transform = transform;
         if (!this._sourceLoaded) { return; }
         let i;
         let coord;
@@ -394,8 +399,6 @@ class SourceCache extends Evented {
         for (i = 0; i < remove.length; i++) {
             this.removeTile(+remove[i]);
         }
-
-        this.transform = transform;
     }
 
     /**
@@ -423,8 +426,8 @@ class SourceCache extends Evented {
                 }
             }
         }
-
-        if (!tile) {
+        const cached = Boolean(tile);
+        if (!cached) {
             const zoom = coord.z;
             const overscaling = zoom > this._source.maxzoom ? Math.pow(2, zoom - this._source.maxzoom) : 1;
             tile = new Tile(wrapped, this._source.tileSize * overscaling, this._source.maxzoom);
@@ -433,7 +436,7 @@ class SourceCache extends Evented {
 
         tile.uses++;
         this._tiles[coord.id] = tile;
-        this._source.fire('dataloading', {tile: tile, coord: tile.coord, dataType: 'tile'});
+        if (!cached) this._source.fire('dataloading', {tile: tile, coord: tile.coord, dataType: 'source'});
 
         return tile;
     }
@@ -475,7 +478,6 @@ class SourceCache extends Evented {
             clearTimeout(this._timers[id]);
             this._timers[id] = undefined;
         }
-        this._source.fire('data', { tile: tile, coord: tile.coord, dataType: 'tile' });
 
         if (tile.uses > 0)
             return;

src/source/tile.js

@@ -155,7 +155,6 @@ class Tile {
             showCollisionBoxes: source.map.showCollisionBoxes
         }, (_, data) => {
             this.reloadSymbolData(data, source.map.style);
-            source.fire('data', {tile: this, coord: this.coord, dataType: 'tile'});
 
             // HACK this is nescessary to fix https://github.com/mapbox/mapbox-gl-js/issues/2986
             if (source.map) source.map.painter.tileExtentVAO.vao = null;

src/source/vector_tile_source.js

@@ -39,8 +39,12 @@ class VectorTileSource extends Evented {
                 return;
             }
             util.extend(this, tileJSON);
-            this.fire('data', {dataType: 'source'});
-            this.fire('source.load');
+             // `content` is included here to prevent a race condition where `Style#_updateSources` is called
+            // before the TileJSON arrives. this makes sure the tiles needed are loaded once TileJSON arrives
+            // ref: https://github.com/mapbox/mapbox-gl-js/pull/4347#discussion_r104418088
+            this.fire('data', {dataType: 'source', sourceDataType: 'metadata'});
+            this.fire('data', {dataType: 'source', sourceDataType: 'content'});
+
         });
     }
 

src/style/style.js

@@ -118,13 +118,15 @@ class Style extends Evented {
             browser.frame(stylesheetLoaded.bind(this, null, stylesheet));
         }
 
-        this.on('source.load', (event) => {
-            const source = this.sourceCaches[event.sourceId].getSource();
-            if (source && source.vectorLayerIds) {
-                for (const layerId in this._layers) {
-                    const layer = this._layers[layerId];
-                    if (layer.source === source.id) {
-                        this._validateLayer(layer);
+        this.on('data', (event) => {
+            if (event.dataType === 'source' && event.sourceDataType === 'metadata') {
+                const source = this.sourceCaches[event.sourceId].getSource();
+                if (source && source.vectorLayerIds) {
+                    for (const layerId in this._layers) {
+                        const layer = this._layers[layerId];
+                        if (layer.source === source.id) {
+                            this._validateLayer(layer);
+                        }
                     }
                 }
             }
@@ -137,7 +139,6 @@ class Style extends Evented {
         if (!layer.sourceLayer) return;
         if (!sourceCache) return;
         const source = sourceCache.getSource();
-
         if (source.type === 'geojson' || (source.vectorLayerIds &&
             source.vectorLayerIds.indexOf(layer.sourceLayer) === -1)) {
             this.fire('error', {

src/ui/control/attribution_control.js

@@ -44,7 +44,7 @@ class AttributionControl {
         this._updateAttributions();
         this._updateEditLink();
 
-        this._map.on('data', this._updateData);
+        this._map.on('sourcedata', this._updateData);
         this._map.on('moveend', this._updateEditLink);
 
         if (compact === undefined) {
@@ -58,7 +58,7 @@ class AttributionControl {
     onRemove() {
         this._container.parentNode.removeChild(this._container);
 
-        this._map.off('data', this._updateData);
+        this._map.off('sourcedata', this._updateData);
         this._map.off('moveend', this._updateEditLink);
         this._map.off('resize', this._updateCompact);
 
@@ -74,16 +74,14 @@ class AttributionControl {
         }
     }
 
-    _updateData(event) {
-        if (event.dataType === 'source') {
-            this._updateAttributions();
-            this._updateEditLink();
-        }
+    _updateData(e) {
+        this._updateAttributions(e);
+        this._updateEditLink();
     }
 
-    _updateAttributions() {
+    _updateAttributions(e) {
         if (!this._map.style) return;
-
+        if (e && e.sourceDataType!=='metadata') return;
         let attributions = [];
 
         const sourceCaches = this._map.style.sourceCaches;

src/ui/control/logo_control.js

@@ -22,22 +22,22 @@ class LogoControl {
         this._map = map;
         this._container = DOM.create('div', 'mapboxgl-ctrl');
 
-        this._map.on('data', this._updateLogo);
+        this._map.on('sourcedata', this._updateLogo);
         this._updateLogo();
         return this._container;
     }
 
     onRemove() {
         this._container.parentNode.removeChild(this._container);
-        this._map.off('data', this._updateLogo);
+        this._map.off('sourcedata', this._updateLogo);
     }
 
     getDefaultPosition() {
         return 'bottom-left';
     }
 
-    _updateLogo() {
-        if (this._logoRequired()) {
+    _updateLogo(e) {
+        if (e && e.sourceDataType==='metadata' && this._logoRequired()) {
             const anchor = DOM.create('a', 'mapboxgl-ctrl-logo');
             anchor.target = "_blank";
             anchor.href = "https://www.mapbox.com/";

src/ui/map.js

@@ -1672,26 +1672,15 @@ function removeNode(node) {
  */
 
 /**
- * Fired when one of the map's sources loads or changes. This event is not fired
- * if a tile belonging to a source loads or changes (that is handled by
- * `tiledata`). See [`MapDataEvent`](#MapDataEvent) for more information.
+ * Fired when one of the map's sources loads or changes, including if a tile belonging
+ * to a source loads or changes. See [`MapDataEvent`](#MapDataEvent) for more information.
  *
  * @event sourcedata
  * @memberof Map
  * @instance
  * @property {MapDataEvent} data
  */
 
- /**
-  * Fired when one of the map's sources' tiles loads or changes. See
-  * [`MapDataEvent`](#MapDataEvent) for more information.
-  *
-  * @event tiledata
-  * @memberof Map
-  * @instance
-  * @property {MapDataEvent} data
-  */
-
 /**
  * Fired when any map data (style, source, tile, etc) begins loading or
  * changing asyncronously. All `dataloading` events are followed by a `data`
@@ -1716,43 +1705,34 @@ function removeNode(node) {
 
 /**
  * Fired when one of the map's sources begins loading or changing asyncronously.
- * This event is not fired if a tile belonging to a source begins loading or
- * changing (that is handled by `tiledataloading`). All `sourcedataloading`
- * events are followed by a `sourcedata` or `error` event. See
- * [`MapDataEvent`](#MapDataEvent) for more information.
+ * All `sourcedataloading` events are followed by a `sourcedata` or `error` event.
+ * See [`MapDataEvent`](#MapDataEvent) for more information.
  *
  * @event sourcedataloading
  * @memberof Map
  * @instance
  * @property {MapDataEvent} data
  */
 
-/**
- * Fired when one of the map's sources' tiles begins loading or changing
- * asyncronously. All `tiledataloading` events are followed by a `tiledata`
- * or `error` event. See [`MapDataEvent`](#MapDataEvent) for more information.
- *
- * @event tiledataloading
- * @memberof Map
- * @instance
- * @property {MapDataEvent} data
- */
-
  /**
   * A `MapDataEvent` object is emitted with the [`Map#data`](#Map.event:data)
   * and [`Map#dataloading`](#Map.event:dataloading) events. Possible values for
   * `dataType`s are:
   *
   * - `'source'`: The non-tile data associated with any source
   * - `'style'`: The [style](https://www.mapbox.com/mapbox-gl-style-spec/) used by the map
-  * - `'tile'`: A vector or raster tile
   *
   * @typedef {Object} MapDataEvent
   * @property {string} type The event type.
   * @property {string} dataType The type of data that has changed. One of `'source'`, `'style'`.
   * @property {boolean} [isSourceLoaded] True if the event has a `dataType` of `source` and the source has no outstanding network requests.
   * @property {Object} [source] The [style spec representation of the source](https://www.mapbox.com/mapbox-gl-style-spec/#sources) if the event has a `dataType` of `source`.
-  * @property {Coordinate} [coord] The coordinate of the tile if the event has a `dataType` of `tile`.
+  * @property {string} [sourceDataType] Included if the event has a `dataType` of `source` and the event signals
+  * that internal data has been received or changed. Possible values are `metadata` and `content`.
+  * @property {Object} [tile] The tile being loaded or changed, if the event has a `dataType` of `source` and
+  * the event is related to loading of a tile.
+  * @property {Coordinate} [coord] The coordinate of the tile if the event has a `dataType` of `source` and
+  * the event is related to loading of a tile.
   */
 
  /**