[core] Introduce Source::setMinimumTileUpdateInterval API

The `Source::setMinimumTileUpdateInterval()` method sets the minimum tile update interval, which is used to throttle the tile update network requests.

Default value is `Duration::zero()`.

include/mbgl/style/source.hpp

@@ -1,9 +1,9 @@
 #pragma once
 
-#include <mbgl/util/noncopyable.hpp>
-#include <mbgl/util/optional.hpp>
-#include <mbgl/util/immutable.hpp>
 #include <mbgl/style/types.hpp>
+#include <mbgl/util/chrono.hpp>
+#include <mbgl/util/immutable.hpp>
+#include <mbgl/util/optional.hpp>
 
 #include <mapbox/std/weak.hpp>
 #include <mapbox/util/type_wrapper.hpp>
@@ -40,8 +40,11 @@ struct LayerTypeInfo;
  *
  *     auto vectorSource = std::make_unique<VectorSource>("my-vector-source");
  */
-class Source : public mbgl::util::noncopyable {
+class Source {
 public:
+    Source(const Source&) = delete;
+    Source& operator=(const Source&) = delete;
+
     virtual ~Source();
 
     // Check whether this source is of the given subtype.
@@ -76,6 +79,14 @@ public:
     void setPrefetchZoomDelta(optional<uint8_t> delta) noexcept;
     optional<uint8_t> getPrefetchZoomDelta() const noexcept;
 
+    // If the given source supports loading tiles from a server,
+    // sets the minimum tile update interval, which is used to
+    // throttle the tile update network requests.
+    //
+    // Default value is `Duration::zero()`.
+    void setMinimumTileUpdateInterval(Duration) noexcept;
+    Duration getMinimumTileUpdateInterval() const noexcept;
+
     // Sets a limit for how much a parent tile can be overscaled.
     //
     // When a set of tiles for a current zoom level is being rendered and some of the

src/mbgl/style/custom_tile_loader.hpp

@@ -1,9 +1,9 @@
 #pragma once
 
+#include <mbgl/actor/actor_ref.hpp>
 #include <mbgl/style/sources/custom_geometry_source.hpp>
 #include <mbgl/tile/tile_id.hpp>
 #include <mbgl/util/geojson.hpp>
-#include <mbgl/actor/actor_ref.hpp>
 
 #include <map>
 #include <mutex>
@@ -14,8 +14,10 @@ class CustomGeometryTile;
 
 namespace style {
 
-class CustomTileLoader : private util::noncopyable {
+class CustomTileLoader {
 public:
+    CustomTileLoader(const CustomTileLoader&) = delete;
+    CustomTileLoader& operator=(const CustomTileLoader&) = delete;
 
     using OverscaledIDFunctionTuple = std::tuple<uint8_t, int16_t, ActorRef<CustomGeometryTile>>;
 

src/mbgl/style/source.cpp

@@ -43,6 +43,18 @@ optional<uint8_t> Source::getPrefetchZoomDelta() const noexcept {
     return baseImpl->getPrefetchZoomDelta();
 }
 
+void Source::setMinimumTileUpdateInterval(Duration interval) noexcept {
+    if (getMinimumTileUpdateInterval() == interval) return;
+    auto newImpl = createMutable();
+    newImpl->setMinimumTileUpdateInterval(interval);
+    baseImpl = std::move(newImpl);
+    observer->onSourceChanged(*this);
+}
+
+Duration Source::getMinimumTileUpdateInterval() const noexcept {
+    return baseImpl->getMinimumTileUpdateInterval();
+}
+
 void Source::setMaxOverscaleFactorForParentTiles(optional<uint8_t> overscaleFactor) noexcept {
     if (getMaxOverscaleFactorForParentTiles() == overscaleFactor) return;
     auto newImpl = createMutable();

src/mbgl/style/source_impl.hpp

@@ -22,15 +22,19 @@ public:
     virtual optional<std::string> getAttribution() const = 0;
     void setPrefetchZoomDelta(optional<uint8_t> delta) noexcept;
     optional<uint8_t> getPrefetchZoomDelta() const noexcept;
+    void setMinimumTileUpdateInterval(Duration interval) { minimumTileUpdateInterval = interval; }
+    Duration getMinimumTileUpdateInterval() const { return minimumTileUpdateInterval; }
     void setMaxOverscaleFactorForParentTiles(optional<uint8_t> overscaleFactor) noexcept;
     optional<uint8_t> getMaxOverscaleFactorForParentTiles() const noexcept;
 
     const SourceType type;
     const std::string id;
-    optional<uint8_t> prefetchZoomDelta;
-    optional<uint8_t> maxOverscaleFactor;
 
 protected:
+    optional<uint8_t> prefetchZoomDelta;
+    optional<uint8_t> maxOverscaleFactor;
+    Duration minimumTileUpdateInterval{Duration::zero()};
+
     Impl(SourceType, std::string);
     Impl(const Impl&) = default;
 };