[core] Removed map attribution API

Since client code can readily access the individual sources, Map doesn’t need to expose a dedicated API for iterating over them.

include/mbgl/map/map.hpp

@@ -155,7 +155,6 @@ public:
     style::Source* getSource(const std::string& sourceID);
     void addSource(std::unique_ptr<style::Source>);
     void removeSource(const std::string& sourceID);
-    std::vector<std::string> getAttributions() const;
 
     // Layers
     style::Layer* getLayer(const std::string& layerID);

include/mbgl/style/source.hpp

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <mbgl/util/noncopyable.hpp>
+#include <mbgl/util/optional.hpp>
 #include <mbgl/style/types.hpp>
 
 #include <memory>
@@ -50,6 +51,8 @@ public:
     // are copied from this source.
     std::unique_ptr<Source> copy(const std::string& id) const;
 
+    optional<std::string> getAttribution() const;
+
     // Private implementation
     class Impl;
     const std::unique_ptr<Impl> baseImpl;

src/mbgl/map/map.cpp

@@ -786,10 +786,6 @@ void Map::removeSource(const std::string& sourceID) {
     }
 }
 
-std::vector<std::string> Map::getAttributions() const {
-    return impl->style ? impl->style->getAttributions() : std::vector<std::string>();
-}
-
 style::Layer* Map::getLayer(const std::string& layerID) {
     if (impl->style) {
         impl->styleMutated = true;

src/mbgl/style/source.cpp

@@ -14,5 +14,9 @@ const std::string& Source::getID() const {
     return baseImpl->id;
 }
 
+optional<std::string> Source::getAttribution() const {
+    return baseImpl->getAttribution();
+}
+
 } // namespace style
 } // namespace mbgl

src/mbgl/style/source_impl.hpp

@@ -71,6 +71,8 @@ public:
     const SourceType type;
     const std::string id;
 
+    virtual optional<std::string> getAttribution() const { return {}; };
+
     bool loaded = false;
 
     // Tracks whether the source is used by any layers visible at the current zoom level. Must

src/mbgl/style/style.cpp

@@ -18,7 +18,6 @@
 #include <mbgl/style/update_parameters.hpp>
 #include <mbgl/style/cascade_parameters.hpp>
 #include <mbgl/style/calculation_parameters.hpp>
-#include <mbgl/style/tile_source_impl.hpp>
 #include <mbgl/sprite/sprite_atlas.hpp>
 #include <mbgl/text/glyph_atlas.hpp>
 #include <mbgl/geometry/line_atlas.hpp>
@@ -26,7 +25,6 @@
 #include <mbgl/renderer/render_tile.hpp>
 #include <mbgl/util/constants.hpp>
 #include <mbgl/util/string.hpp>
-#include <mbgl/util/tileset.hpp>
 #include <mbgl/platform/log.hpp>
 #include <mbgl/math/minmax.hpp>
 
@@ -295,28 +293,6 @@ Source* Style::getSource(const std::string& id) const {
     return it != sources.end() ? it->get() : nullptr;
 }
 
-std::vector<std::string> Style::getAttributions() const {
-    std::vector<std::string> result;
-    for (const auto& source : sources) {
-        switch (source->baseImpl->type) {
-        case SourceType::Vector:
-        case SourceType::Raster: {
-            style::TileSourceImpl* tileSource = static_cast<style::TileSourceImpl*>(source->baseImpl.get());
-            auto attribution = tileSource->getAttribution();
-            if (!attribution.empty()) {
-                result.push_back(std::move(attribution));
-            }
-        }
-
-        case SourceType::GeoJSON:
-        case SourceType::Video:
-        case SourceType::Annotations:
-            break;
-        }
-    }
-    return result;
-}
-
 bool Style::hasTransitions() const {
     return hasPendingTransitions;
 }

src/mbgl/style/style.hpp

@@ -67,7 +67,6 @@ public:
     Source* getSource(const std::string& id) const;
     void addSource(std::unique_ptr<Source>);
     void removeSource(const std::string& sourceID);
-    std::vector<std::string> getAttributions() const;
 
     std::vector<const Layer*> getLayers() const;
     Layer* getLayer(const std::string& id) const;

src/mbgl/style/tile_source_impl.cpp

@@ -118,8 +118,12 @@ Range<uint8_t> TileSourceImpl::getZoomRange() {
     return tileset.zoomRange;
 }
 
-std::string TileSourceImpl::getAttribution() const {
-    return loaded ? tileset.attribution : "";
+optional<std::string> TileSourceImpl::getAttribution() const {
+    if (loaded && !tileset.attribution.empty()) {
+        return tileset.attribution;
+    } else {
+        return {};
+    }
 }
 
 } // namespace style

src/mbgl/style/tile_source_impl.hpp

@@ -34,7 +34,7 @@ public:
         return urlOrTileset;
     }
     
-    std::string getAttribution() const;
+    optional<std::string> getAttribution() const override;
 
 protected:
     Range<uint8_t> getZoomRange() final;