From c1445913220023fdaf8ec5960eb6cba27c348864 Mon Sep 17 00:00:00 2001
From: Mikhail Pozdnyakov <mikhail.pozdnyakov@mapbox.com>
Date: Thu, 27 Jun 2019 17:06:49 +0300
Subject: [core] Introduce LayerProperties::constantsMask()

Constants mask for data-driven paint properties is a reliable
criteria of whether the given updated properties can still be used
with the existing bucket (and the gl program instance).
---
 include/mbgl/style/layer_properties.hpp            |  3 ++-
 .../style/layers/background_layer_properties.cpp   |  4 ++++
 .../style/layers/background_layer_properties.hpp   |  2 ++
 src/mbgl/style/layers/circle_layer_properties.cpp  |  4 ++++
 src/mbgl/style/layers/circle_layer_properties.hpp  |  2 ++
 .../layers/fill_extrusion_layer_properties.cpp     |  4 ++++
 .../layers/fill_extrusion_layer_properties.hpp     |  2 ++
 src/mbgl/style/layers/fill_layer_properties.cpp    |  4 ++++
 src/mbgl/style/layers/fill_layer_properties.hpp    |  2 ++
 src/mbgl/style/layers/heatmap_layer_properties.cpp |  4 ++++
 src/mbgl/style/layers/heatmap_layer_properties.hpp |  2 ++
 .../style/layers/hillshade_layer_properties.cpp    |  4 ++++
 .../style/layers/hillshade_layer_properties.hpp    |  2 ++
 src/mbgl/style/layers/layer_properties.cpp.ejs     |  4 ++++
 src/mbgl/style/layers/layer_properties.hpp.ejs     |  2 ++
 src/mbgl/style/layers/line_layer_properties.cpp    |  4 ++++
 src/mbgl/style/layers/line_layer_properties.hpp    |  2 ++
 src/mbgl/style/layers/raster_layer_properties.cpp  |  4 ++++
 src/mbgl/style/layers/raster_layer_properties.hpp  |  2 ++
 src/mbgl/style/layers/symbol_layer_properties.cpp  |  4 ++++
 src/mbgl/style/layers/symbol_layer_properties.hpp  |  2 ++
 src/mbgl/style/properties.hpp                      | 22 ++++++++++++++++++++++
 22 files changed, 84 insertions(+), 1 deletion(-)

diff --git a/include/mbgl/style/layer_properties.hpp b/include/mbgl/style/layer_properties.hpp
index 301a048e50..c238faf02f 100644
--- a/include/mbgl/style/layer_properties.hpp
+++ b/include/mbgl/style/layer_properties.hpp
@@ -13,7 +13,8 @@ namespace style {
 class LayerProperties {
 public:
     virtual ~LayerProperties() = default;
-
+    // Returns constants mask for the data-driven properties.
+    virtual unsigned long constantsMask() const { return 0u; }
     Immutable<Layer::Impl> baseImpl;
 
 protected:
diff --git a/src/mbgl/style/layers/background_layer_properties.cpp b/src/mbgl/style/layers/background_layer_properties.cpp
index f0da811379..63f6a7be68 100644
--- a/src/mbgl/style/layers/background_layer_properties.cpp
+++ b/src/mbgl/style/layers/background_layer_properties.cpp
@@ -21,6 +21,10 @@ BackgroundLayerProperties::BackgroundLayerProperties(
 
 BackgroundLayerProperties::~BackgroundLayerProperties() = default;
 
+unsigned long BackgroundLayerProperties::constantsMask() const {
+    return evaluated.constantsMask();
+}
+
 const BackgroundLayer::Impl& BackgroundLayerProperties::layerImpl() const {
     return static_cast<const BackgroundLayer::Impl&>(*baseImpl);
 }
diff --git a/src/mbgl/style/layers/background_layer_properties.hpp b/src/mbgl/style/layers/background_layer_properties.hpp
index 371e8639f1..56db696533 100644
--- a/src/mbgl/style/layers/background_layer_properties.hpp
+++ b/src/mbgl/style/layers/background_layer_properties.hpp
@@ -41,6 +41,8 @@ public:
         BackgroundPaintProperties::PossiblyEvaluated);
     ~BackgroundLayerProperties() override;
 
+    unsigned long constantsMask() const override;
+
     const BackgroundLayer::Impl& layerImpl() const;
     // Data members.
     CrossfadeParameters crossfade;
diff --git a/src/mbgl/style/layers/circle_layer_properties.cpp b/src/mbgl/style/layers/circle_layer_properties.cpp
index fbb4aeabd4..03a4a8f56e 100644
--- a/src/mbgl/style/layers/circle_layer_properties.cpp
+++ b/src/mbgl/style/layers/circle_layer_properties.cpp
@@ -19,6 +19,10 @@ CircleLayerProperties::CircleLayerProperties(
 
 CircleLayerProperties::~CircleLayerProperties() = default;
 
+unsigned long CircleLayerProperties::constantsMask() const {
+    return evaluated.constantsMask();
+}
+
 const CircleLayer::Impl& CircleLayerProperties::layerImpl() const {
     return static_cast<const CircleLayer::Impl&>(*baseImpl);
 }
diff --git a/src/mbgl/style/layers/circle_layer_properties.hpp b/src/mbgl/style/layers/circle_layer_properties.hpp
index 17727c79eb..1aaa3bb3e3 100644
--- a/src/mbgl/style/layers/circle_layer_properties.hpp
+++ b/src/mbgl/style/layers/circle_layer_properties.hpp
@@ -80,6 +80,8 @@ public:
         CirclePaintProperties::PossiblyEvaluated);
     ~CircleLayerProperties() override;
 
+    unsigned long constantsMask() const override;
+
     const CircleLayer::Impl& layerImpl() const;
     // Data members.
     CirclePaintProperties::PossiblyEvaluated evaluated;
diff --git a/src/mbgl/style/layers/fill_extrusion_layer_properties.cpp b/src/mbgl/style/layers/fill_extrusion_layer_properties.cpp
index 7986c40923..ddfe9c8468 100644
--- a/src/mbgl/style/layers/fill_extrusion_layer_properties.cpp
+++ b/src/mbgl/style/layers/fill_extrusion_layer_properties.cpp
@@ -21,6 +21,10 @@ FillExtrusionLayerProperties::FillExtrusionLayerProperties(
 
 FillExtrusionLayerProperties::~FillExtrusionLayerProperties() = default;
 
+unsigned long FillExtrusionLayerProperties::constantsMask() const {
+    return evaluated.constantsMask();
+}
+
 const FillExtrusionLayer::Impl& FillExtrusionLayerProperties::layerImpl() const {
     return static_cast<const FillExtrusionLayer::Impl&>(*baseImpl);
 }
diff --git a/src/mbgl/style/layers/fill_extrusion_layer_properties.hpp b/src/mbgl/style/layers/fill_extrusion_layer_properties.hpp
index f5aeaf5c73..69b8a0bcb8 100644
--- a/src/mbgl/style/layers/fill_extrusion_layer_properties.hpp
+++ b/src/mbgl/style/layers/fill_extrusion_layer_properties.hpp
@@ -66,6 +66,8 @@ public:
         FillExtrusionPaintProperties::PossiblyEvaluated);
     ~FillExtrusionLayerProperties() override;
 
+    unsigned long constantsMask() const override;
+
     const FillExtrusionLayer::Impl& layerImpl() const;
     // Data members.
     CrossfadeParameters crossfade;
diff --git a/src/mbgl/style/layers/fill_layer_properties.cpp b/src/mbgl/style/layers/fill_layer_properties.cpp
index 55e5a58cce..de917177f6 100644
--- a/src/mbgl/style/layers/fill_layer_properties.cpp
+++ b/src/mbgl/style/layers/fill_layer_properties.cpp
@@ -21,6 +21,10 @@ FillLayerProperties::FillLayerProperties(
 
 FillLayerProperties::~FillLayerProperties() = default;
 
+unsigned long FillLayerProperties::constantsMask() const {
+    return evaluated.constantsMask();
+}
+
 const FillLayer::Impl& FillLayerProperties::layerImpl() const {
     return static_cast<const FillLayer::Impl&>(*baseImpl);
 }
diff --git a/src/mbgl/style/layers/fill_layer_properties.hpp b/src/mbgl/style/layers/fill_layer_properties.hpp
index 376852d254..4e1b6970fe 100644
--- a/src/mbgl/style/layers/fill_layer_properties.hpp
+++ b/src/mbgl/style/layers/fill_layer_properties.hpp
@@ -61,6 +61,8 @@ public:
         FillPaintProperties::PossiblyEvaluated);
     ~FillLayerProperties() override;
 
+    unsigned long constantsMask() const override;
+
     const FillLayer::Impl& layerImpl() const;
     // Data members.
     CrossfadeParameters crossfade;
diff --git a/src/mbgl/style/layers/heatmap_layer_properties.cpp b/src/mbgl/style/layers/heatmap_layer_properties.cpp
index 03a73be103..cc50073651 100644
--- a/src/mbgl/style/layers/heatmap_layer_properties.cpp
+++ b/src/mbgl/style/layers/heatmap_layer_properties.cpp
@@ -19,6 +19,10 @@ HeatmapLayerProperties::HeatmapLayerProperties(
 
 HeatmapLayerProperties::~HeatmapLayerProperties() = default;
 
+unsigned long HeatmapLayerProperties::constantsMask() const {
+    return evaluated.constantsMask();
+}
+
 const HeatmapLayer::Impl& HeatmapLayerProperties::layerImpl() const {
     return static_cast<const HeatmapLayer::Impl&>(*baseImpl);
 }
diff --git a/src/mbgl/style/layers/heatmap_layer_properties.hpp b/src/mbgl/style/layers/heatmap_layer_properties.hpp
index dda9808e77..634cbef1ed 100644
--- a/src/mbgl/style/layers/heatmap_layer_properties.hpp
+++ b/src/mbgl/style/layers/heatmap_layer_properties.hpp
@@ -49,6 +49,8 @@ public:
         HeatmapPaintProperties::PossiblyEvaluated);
     ~HeatmapLayerProperties() override;
 
+    unsigned long constantsMask() const override;
+
     const HeatmapLayer::Impl& layerImpl() const;
     // Data members.
     HeatmapPaintProperties::PossiblyEvaluated evaluated;
diff --git a/src/mbgl/style/layers/hillshade_layer_properties.cpp b/src/mbgl/style/layers/hillshade_layer_properties.cpp
index 407acb6fc0..72acc235e2 100644
--- a/src/mbgl/style/layers/hillshade_layer_properties.cpp
+++ b/src/mbgl/style/layers/hillshade_layer_properties.cpp
@@ -19,6 +19,10 @@ HillshadeLayerProperties::HillshadeLayerProperties(
 
 HillshadeLayerProperties::~HillshadeLayerProperties() = default;
 
+unsigned long HillshadeLayerProperties::constantsMask() const {
+    return evaluated.constantsMask();
+}
+
 const HillshadeLayer::Impl& HillshadeLayerProperties::layerImpl() const {
     return static_cast<const HillshadeLayer::Impl&>(*baseImpl);
 }
diff --git a/src/mbgl/style/layers/hillshade_layer_properties.hpp b/src/mbgl/style/layers/hillshade_layer_properties.hpp
index 85ef8b967c..e38e5bb5b3 100644
--- a/src/mbgl/style/layers/hillshade_layer_properties.hpp
+++ b/src/mbgl/style/layers/hillshade_layer_properties.hpp
@@ -55,6 +55,8 @@ public:
         HillshadePaintProperties::PossiblyEvaluated);
     ~HillshadeLayerProperties() override;
 
+    unsigned long constantsMask() const override;
+
     const HillshadeLayer::Impl& layerImpl() const;
     // Data members.
     HillshadePaintProperties::PossiblyEvaluated evaluated;
diff --git a/src/mbgl/style/layers/layer_properties.cpp.ejs b/src/mbgl/style/layers/layer_properties.cpp.ejs
index 2c8e1ce9a0..fcdcfda7be 100644
--- a/src/mbgl/style/layers/layer_properties.cpp.ejs
+++ b/src/mbgl/style/layers/layer_properties.cpp.ejs
@@ -30,6 +30,10 @@ namespace style {
 
 <%- camelize(type) %>LayerProperties::~<%- camelize(type) %>LayerProperties() = default;
 
+unsigned long <%- camelize(type) %>LayerProperties::constantsMask() const {
+    return evaluated.constantsMask();
+}
+
 const <%- camelize(type) %>Layer::Impl& <%- camelize(type) %>LayerProperties::layerImpl() const {
     return static_cast<const <%- camelize(type) %>Layer::Impl&>(*baseImpl);
 }
diff --git a/src/mbgl/style/layers/layer_properties.hpp.ejs b/src/mbgl/style/layers/layer_properties.hpp.ejs
index 277cfd173b..4513146d6d 100644
--- a/src/mbgl/style/layers/layer_properties.hpp.ejs
+++ b/src/mbgl/style/layers/layer_properties.hpp.ejs
@@ -72,6 +72,8 @@ public:
         <%- camelize(type) %>PaintProperties::PossiblyEvaluated);
     ~<%- camelize(type) %>LayerProperties() override;
 
+    unsigned long constantsMask() const override;
+
     const <%- camelize(type) %>Layer::Impl& layerImpl() const;
     // Data members.
 <% if (type === 'background' || type === 'fill' || type === 'line' || type === 'fill-extrusion') { -%>
diff --git a/src/mbgl/style/layers/line_layer_properties.cpp b/src/mbgl/style/layers/line_layer_properties.cpp
index 09fb6ff80c..46b220661c 100644
--- a/src/mbgl/style/layers/line_layer_properties.cpp
+++ b/src/mbgl/style/layers/line_layer_properties.cpp
@@ -21,6 +21,10 @@ LineLayerProperties::LineLayerProperties(
 
 LineLayerProperties::~LineLayerProperties() = default;
 
+unsigned long LineLayerProperties::constantsMask() const {
+    return evaluated.constantsMask();
+}
+
 const LineLayer::Impl& LineLayerProperties::layerImpl() const {
     return static_cast<const LineLayer::Impl&>(*baseImpl);
 }
diff --git a/src/mbgl/style/layers/line_layer_properties.hpp b/src/mbgl/style/layers/line_layer_properties.hpp
index 7463d94393..dac6cebae0 100644
--- a/src/mbgl/style/layers/line_layer_properties.hpp
+++ b/src/mbgl/style/layers/line_layer_properties.hpp
@@ -113,6 +113,8 @@ public:
         LinePaintProperties::PossiblyEvaluated);
     ~LineLayerProperties() override;
 
+    unsigned long constantsMask() const override;
+
     const LineLayer::Impl& layerImpl() const;
     // Data members.
     CrossfadeParameters crossfade;
diff --git a/src/mbgl/style/layers/raster_layer_properties.cpp b/src/mbgl/style/layers/raster_layer_properties.cpp
index 4d9245a218..77bdb62b8d 100644
--- a/src/mbgl/style/layers/raster_layer_properties.cpp
+++ b/src/mbgl/style/layers/raster_layer_properties.cpp
@@ -19,6 +19,10 @@ RasterLayerProperties::RasterLayerProperties(
 
 RasterLayerProperties::~RasterLayerProperties() = default;
 
+unsigned long RasterLayerProperties::constantsMask() const {
+    return evaluated.constantsMask();
+}
+
 const RasterLayer::Impl& RasterLayerProperties::layerImpl() const {
     return static_cast<const RasterLayer::Impl&>(*baseImpl);
 }
diff --git a/src/mbgl/style/layers/raster_layer_properties.hpp b/src/mbgl/style/layers/raster_layer_properties.hpp
index 61aa32de2d..9ddd6cc790 100644
--- a/src/mbgl/style/layers/raster_layer_properties.hpp
+++ b/src/mbgl/style/layers/raster_layer_properties.hpp
@@ -65,6 +65,8 @@ public:
         RasterPaintProperties::PossiblyEvaluated);
     ~RasterLayerProperties() override;
 
+    unsigned long constantsMask() const override;
+
     const RasterLayer::Impl& layerImpl() const;
     // Data members.
     RasterPaintProperties::PossiblyEvaluated evaluated;
diff --git a/src/mbgl/style/layers/symbol_layer_properties.cpp b/src/mbgl/style/layers/symbol_layer_properties.cpp
index aeca39b419..5e50535377 100644
--- a/src/mbgl/style/layers/symbol_layer_properties.cpp
+++ b/src/mbgl/style/layers/symbol_layer_properties.cpp
@@ -19,6 +19,10 @@ SymbolLayerProperties::SymbolLayerProperties(
 
 SymbolLayerProperties::~SymbolLayerProperties() = default;
 
+unsigned long SymbolLayerProperties::constantsMask() const {
+    return evaluated.constantsMask();
+}
+
 const SymbolLayer::Impl& SymbolLayerProperties::layerImpl() const {
     return static_cast<const SymbolLayer::Impl&>(*baseImpl);
 }
diff --git a/src/mbgl/style/layers/symbol_layer_properties.hpp b/src/mbgl/style/layers/symbol_layer_properties.hpp
index 7b630a1ca3..0c2bcd2661 100644
--- a/src/mbgl/style/layers/symbol_layer_properties.hpp
+++ b/src/mbgl/style/layers/symbol_layer_properties.hpp
@@ -341,6 +341,8 @@ public:
         SymbolPaintProperties::PossiblyEvaluated);
     ~SymbolLayerProperties() override;
 
+    unsigned long constantsMask() const override;
+
     const SymbolLayer::Impl& layerImpl() const;
     // Data members.
     SymbolPaintProperties::PossiblyEvaluated evaluated;
diff --git a/src/mbgl/style/properties.hpp b/src/mbgl/style/properties.hpp
index 7f58ff223d..9d66f850de 100644
--- a/src/mbgl/style/properties.hpp
+++ b/src/mbgl/style/properties.hpp
@@ -9,6 +9,8 @@
 #include <mbgl/util/indexed_tuple.hpp>
 #include <mbgl/util/ignore.hpp>
 
+#include <bitset>
+
 namespace mbgl {
 
 class GeometryTileFeature;
@@ -102,6 +104,22 @@ struct IsDataDriven : std::integral_constant<bool, P::IsDataDriven> {};
 template <class P>
 struct IsOverridable : std::integral_constant<bool, P::IsOverridable> {};
 
+template <class Ps>
+struct ConstantsMask;
+
+template <class... Ps>
+struct ConstantsMask<TypeList<Ps...>> {
+    template <class Properties>
+    static unsigned long getMask(const Properties& properties) {
+        std::bitset<sizeof... (Ps)> result;
+        util::ignore({
+            result.set(TypeIndex<Ps, Ps...>::value,
+                       properties.template get<Ps>().isConstant())...
+        });
+        return result.to_ulong();
+    }
+};
+
 template <class... Ps>
 class Properties {
 public:
@@ -172,6 +190,10 @@ public:
                 evaluate<Ps>(z, feature)...
             };
         }
+
+        unsigned long constantsMask() const {
+            return ConstantsMask<DataDrivenProperties>::getMask(*this);
+        }
     };
 
     class Unevaluated : public Tuple<UnevaluatedTypes> {
-- 
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