[core] make sure tiles are not treated as complete until all worker operations completed

Previously, when we started a worker operation that eventually throws an exception (e.g. due to the tile not being parseable), and then enqueue another worker operation while the first one is processing, we treated the worker as idle once the first operation's error callback fired, even though the second operation was still in progress. Due to our use of coalescing, I was unable to come up with a reliable test since we'd need to reproduce the behavior described above, which is timing dependent.

7 files changed, 43 insertions, 37 deletions

diff --git a/src/mbgl/tile/geometry_tile.cpp b/src/mbgl/tile/geometry_tile.cpp
index fafd9f7ae7..c99149893d 100644
--- a/src/mbgl/tile/geometry_tile.cpp
+++ b/src/mbgl/tile/geometry_tile.cpp
@@ -140,9 +140,10 @@ void GeometryTile::setLayers(const std::vector<Immutable<Layer::Impl>>& layers)
     worker.invoke(&GeometryTileWorker::setLayers, std::move(impls), correlationID);
 }
 
-void GeometryTile::onLayout(LayoutResult result) {
+void GeometryTile::onLayout(LayoutResult result, const uint64_t resultCorrelationID) {
     loaded = true;
     renderable = true;
+    (void)resultCorrelationID;
     nonSymbolBuckets = std::move(result.nonSymbolBuckets);
     featureIndex = std::move(result.featureIndex);
     data = std::move(result.tileData);
@@ -150,10 +151,10 @@ void GeometryTile::onLayout(LayoutResult result) {
     observer->onTileChanged(*this);
 }
 
-void GeometryTile::onPlacement(PlacementResult result) {
+void GeometryTile::onPlacement(PlacementResult result, const uint64_t resultCorrelationID) {
     loaded = true;
     renderable = true;
-    if (result.correlationID == correlationID) {
+    if (resultCorrelationID == correlationID) {
         pending = false;
     }
     symbolBuckets = std::move(result.symbolBuckets);
@@ -170,9 +171,11 @@ void GeometryTile::onPlacement(PlacementResult result) {
     observer->onTileChanged(*this);
 }
 
-void GeometryTile::onError(std::exception_ptr err) {
+void GeometryTile::onError(std::exception_ptr err, const uint64_t resultCorrelationID) {
     loaded = true;
-    pending = false;
+    if (resultCorrelationID == correlationID) {
+        pending = false;
+    }
     observer->onTileError(*this, err);
 }
     
diff --git a/src/mbgl/tile/geometry_tile.hpp b/src/mbgl/tile/geometry_tile.hpp
index ebad0f5410..82c39f782e 100644
--- a/src/mbgl/tile/geometry_tile.hpp
+++ b/src/mbgl/tile/geometry_tile.hpp
@@ -69,18 +69,15 @@ public:
         std::unordered_map<std::string, std::shared_ptr<Bucket>> nonSymbolBuckets;
         std::unique_ptr<FeatureIndex> featureIndex;
         std::unique_ptr<GeometryTileData> tileData;
-        uint64_t correlationID;
 
         LayoutResult(std::unordered_map<std::string, std::shared_ptr<Bucket>> nonSymbolBuckets_,
                      std::unique_ptr<FeatureIndex> featureIndex_,
-                     std::unique_ptr<GeometryTileData> tileData_,
-                     uint64_t correlationID_)
+                     std::unique_ptr<GeometryTileData> tileData_)
             : nonSymbolBuckets(std::move(nonSymbolBuckets_)),
               featureIndex(std::move(featureIndex_)),
-              tileData(std::move(tileData_)),
-              correlationID(correlationID_) {}
+              tileData(std::move(tileData_)) {}
     };
-    void onLayout(LayoutResult);
+    void onLayout(LayoutResult, uint64_t correlationID);
 
     class PlacementResult {
     public:
@@ -88,22 +85,19 @@ public:
         std::unique_ptr<CollisionTile> collisionTile;
         optional<AlphaImage> glyphAtlasImage;
         optional<PremultipliedImage> iconAtlasImage;
-        uint64_t correlationID;
 
         PlacementResult(std::unordered_map<std::string, std::shared_ptr<Bucket>> symbolBuckets_,
                         std::unique_ptr<CollisionTile> collisionTile_,
                         optional<AlphaImage> glyphAtlasImage_,
-                        optional<PremultipliedImage> iconAtlasImage_,
-                        uint64_t correlationID_)
+                        optional<PremultipliedImage> iconAtlasImage_)
             : symbolBuckets(std::move(symbolBuckets_)),
               collisionTile(std::move(collisionTile_)),
               glyphAtlasImage(std::move(glyphAtlasImage_)),
-              iconAtlasImage(std::move(iconAtlasImage_)),
-              correlationID(correlationID_) {}
+              iconAtlasImage(std::move(iconAtlasImage_)) {}
     };
-    void onPlacement(PlacementResult);
+    void onPlacement(PlacementResult, uint64_t correlationID);
 
-    void onError(std::exception_ptr);
+    void onError(std::exception_ptr, uint64_t correlationID);
     
     float yStretch() const override;
     
diff --git a/src/mbgl/tile/geometry_tile_worker.cpp b/src/mbgl/tile/geometry_tile_worker.cpp
index 4af35e2326..50429420c3 100644
--- a/src/mbgl/tile/geometry_tile_worker.cpp
+++ b/src/mbgl/tile/geometry_tile_worker.cpp
@@ -88,7 +88,7 @@ void GeometryTileWorker::setData(std::unique_ptr<const GeometryTileData> data_,
             break;
         }
     } catch (...) {
-        parent.invoke(&GeometryTile::onError, std::current_exception());
+        parent.invoke(&GeometryTile::onError, std::current_exception(), correlationID);
     }
 }
 
@@ -112,7 +112,7 @@ void GeometryTileWorker::setLayers(std::vector<Immutable<Layer::Impl>> layers_,
             break;
         }
     } catch (...) {
-        parent.invoke(&GeometryTile::onError, std::current_exception());
+        parent.invoke(&GeometryTile::onError, std::current_exception(), correlationID);
     }
 }
 
@@ -136,7 +136,7 @@ void GeometryTileWorker::setPlacementConfig(PlacementConfig placementConfig_, ui
             break;
         }
     } catch (...) {
-        parent.invoke(&GeometryTile::onError, std::current_exception());
+        parent.invoke(&GeometryTile::onError, std::current_exception(), correlationID);
     }
 }
 
@@ -161,7 +161,7 @@ void GeometryTileWorker::symbolDependenciesChanged() {
             break;
         }
     } catch (...) {
-        parent.invoke(&GeometryTile::onError, std::current_exception());
+        parent.invoke(&GeometryTile::onError, std::current_exception(), correlationID);
     }
 }
 
@@ -187,7 +187,7 @@ void GeometryTileWorker::coalesced() {
             break;
         }
     } catch (...) {
-        parent.invoke(&GeometryTile::onError, std::current_exception());
+        parent.invoke(&GeometryTile::onError, std::current_exception(), correlationID);
     }
 }
 
@@ -357,8 +357,7 @@ void GeometryTileWorker::redoLayout() {
         std::move(buckets),
         std::move(featureIndex),
         *data ? (*data)->clone() : nullptr,
-        correlationID
-    });
+    }, correlationID);
 
     attemptPlacement();
 }
@@ -422,8 +421,7 @@ void GeometryTileWorker::attemptPlacement() {
         std::move(collisionTile),
         std::move(glyphAtlasImage),
         std::move(iconAtlasImage),
-        correlationID
-    });
+    }, correlationID);
 }
 
 } // namespace mbgl
diff --git a/src/mbgl/tile/raster_tile.cpp b/src/mbgl/tile/raster_tile.cpp
index 76c74ab964..2a3c9eeb0e 100644
--- a/src/mbgl/tile/raster_tile.cpp
+++ b/src/mbgl/tile/raster_tile.cpp
@@ -37,18 +37,27 @@ void RasterTile::setData(std::shared_ptr<const std::string> data,
                              optional<Timestamp> expires_) {
     modified = modified_;
     expires = expires_;
-    worker.invoke(&RasterTileWorker::parse, data);
+
+    pending = true;
+    ++correlationID;
+    worker.invoke(&RasterTileWorker::parse, data, correlationID);
 }
 
-void RasterTile::onParsed(std::unique_ptr<RasterBucket> result) {
+void RasterTile::onParsed(std::unique_ptr<RasterBucket> result, const uint64_t resultCorrelationID) {
     bucket = std::move(result);
     loaded = true;
+    if (resultCorrelationID == correlationID) {
+        pending = false;
+    }
     renderable = bucket ? true : false;
     observer->onTileChanged(*this);
 }
 
-void RasterTile::onError(std::exception_ptr err) {
+void RasterTile::onError(std::exception_ptr err, const uint64_t resultCorrelationID) {
     loaded = true;
+    if (resultCorrelationID == correlationID) {
+        pending = false;
+    }
     observer->onTileError(*this, err);
 }
 
diff --git a/src/mbgl/tile/raster_tile.hpp b/src/mbgl/tile/raster_tile.hpp
index 28a27b2b37..2cb64e8ed7 100644
--- a/src/mbgl/tile/raster_tile.hpp
+++ b/src/mbgl/tile/raster_tile.hpp
@@ -36,8 +36,8 @@ public:
 
     void setMask(TileMask&&) override;
 
-    void onParsed(std::unique_ptr<RasterBucket> result);
-    void onError(std::exception_ptr);
+    void onParsed(std::unique_ptr<RasterBucket> result, uint64_t correlationID);
+    void onError(std::exception_ptr, uint64_t correlationID);
 
 private:
     TileLoader<RasterTile> loader;
@@ -45,6 +45,8 @@ private:
     std::shared_ptr<Mailbox> mailbox;
     Actor<RasterTileWorker> worker;
 
+    uint64_t correlationID = 0;
+
     // Contains the Bucket object for the tile. Buckets are render
     // objects and they get added by tile parsing operations.
     std::unique_ptr<RasterBucket> bucket;
diff --git a/src/mbgl/tile/raster_tile_worker.cpp b/src/mbgl/tile/raster_tile_worker.cpp
index 3c8af97b40..4afa876429 100644
--- a/src/mbgl/tile/raster_tile_worker.cpp
+++ b/src/mbgl/tile/raster_tile_worker.cpp
@@ -10,17 +10,17 @@ RasterTileWorker::RasterTileWorker(ActorRef<RasterTileWorker>, ActorRef<RasterTi
     : parent(std::move(parent_)) {
 }
 
-void RasterTileWorker::parse(std::shared_ptr<const std::string> data) {
+void RasterTileWorker::parse(std::shared_ptr<const std::string> data, uint64_t correlationID) {
     if (!data) {
-        parent.invoke(&RasterTile::onParsed, nullptr); // No data; empty tile.
+        parent.invoke(&RasterTile::onParsed, nullptr, correlationID); // No data; empty tile.
         return;
     }
 
     try {
         auto bucket = std::make_unique<RasterBucket>(decodeImage(*data));
-        parent.invoke(&RasterTile::onParsed, std::move(bucket));
+        parent.invoke(&RasterTile::onParsed, std::move(bucket), correlationID);
     } catch (...) {
-        parent.invoke(&RasterTile::onError, std::current_exception());
+        parent.invoke(&RasterTile::onError, std::current_exception(), correlationID);
     }
 }
 
diff --git a/src/mbgl/tile/raster_tile_worker.hpp b/src/mbgl/tile/raster_tile_worker.hpp
index 44bc37ca5d..520973c3c3 100644
--- a/src/mbgl/tile/raster_tile_worker.hpp
+++ b/src/mbgl/tile/raster_tile_worker.hpp
@@ -13,7 +13,7 @@ class RasterTileWorker {
 public:
     RasterTileWorker(ActorRef<RasterTileWorker>, ActorRef<RasterTile>);
 
-    void parse(std::shared_ptr<const std::string> data);
+    void parse(std::shared_ptr<const std::string> data, uint64_t correlationID);
 
 private:
     ActorRef<RasterTile> parent;