1 files changed, 108 insertions, 0 deletions
diff --git a/src/mbgl/tile/tile_data.hpp b/src/mbgl/tile/tile_data.hpp
new file mode 100644
index 0000000000..90196f8a42
--- /dev/null
+++ b/src/mbgl/tile/tile_data.hpp
@@ -0,0 +1,108 @@
+#ifndef MBGL_MAP_TILE_DATA
+#define MBGL_MAP_TILE_DATA
+
+#include <mbgl/util/noncopyable.hpp>
+#include <mbgl/util/chrono.hpp>
+#include <mbgl/util/optional.hpp>
+#include <mbgl/map/tile_id.hpp>
+#include <mbgl/renderer/bucket.hpp>
+#include <mbgl/text/placement_config.hpp>
+
+#include <atomic>
+#include <string>
+#include <memory>
+#include <functional>
+
+namespace mbgl {
+
+class StyleLayer;
+class Worker;
+class DebugBucket;
+
+class TileData : private util::noncopyable {
+public:
+    // initial:
+    //   Initial state, only used when the TileData object is created.
+    //
+    // invalid:
+    //   FIXME: This state has a bit of overlap with 'initial' and 'obsolete'.
+    //
+    //   We report TileData being 'invalid' on Source::hasTile if we don't have the
+    //   TileData yet, then Source creates a request. This is misleading because
+    //   the TileData object is not effectively on the 'invalid' state and will
+    //   cause tiles on 'invalid' state to get reloaded.
+    //
+    // loading:
+    //   A request to the FileSource was made for the actual tile data and TileData
+    //   is waiting for it to arrive.
+    //
+    // loaded:
+    //   The actual tile data has arrived and the tile can be parsed.
+    //
+    // partial:
+    //   TileData is partially parsed, some buckets are still waiting for dependencies
+    //   to arrive, but it is good for rendering. Partial tiles can also be re-parsed,
+    //   but might remain in the same state if dependencies are still missing.
+    //
+    // parsed:
+    //   TileData is fully parsed and its contents won't change from this point. This
+    //   is the only state which is safe to cache this object.
+    //
+    // obsolete:
+    //   The TileData can go to obsolete from any state, due to parsing or loading error,
+    //   request cancellation or because the tile is no longer in use.
+    enum class State {
+        initial,
+        invalid,
+        loading,
+        loaded,
+        partial,
+        parsed,
+        obsolete
+    };
+
+    static const char* StateToString(State);
+
+    // Tile data considered "Ready" can be used for rendering. Data in
+    // partial state is still waiting for network resources but can also
+    // be rendered, although layers will be missing.
+    inline static bool isReadyState(const State& state) {
+        return state == State::partial || state == State::parsed;
+    }
+
+    TileData(const TileID&);
+    virtual ~TileData();
+
+    // Mark this tile as no longer needed and cancel any pending work.
+    virtual void cancel() = 0;
+
+    virtual Bucket* getBucket(const StyleLayer&) = 0;
+
+    virtual bool parsePending(std::function<void (std::exception_ptr)>) { return true; }
+    virtual void redoPlacement(PlacementConfig, const std::function<void()>&) {}
+    virtual void redoPlacement(const std::function<void()>&) {}
+
+    bool isReady() const {
+        return isReadyState(state);
+    }
+
+    State getState() const {
+        return state;
+    }
+
+    void dumpDebugLogs() const;
+
+    const TileID id;
+    optional<SystemTimePoint> modified;
+    optional<SystemTimePoint> expires;
+
+    // Contains the tile ID string for painting debug information.
+    std::unique_ptr<DebugBucket> debugBucket;
+
+protected:
+    std::atomic<State> state;
+};
+
+} // namespace mbgl
+
+#endif