[core] Rename data ⇢ tile; use Resource::Necessity

1 files changed, 116 insertions, 121 deletions

diff --git a/test/algorithm/update_renderables.cpp b/test/algorithm/update_renderables.cpp
index dcc43a83f3..c284c37475 100644
--- a/test/algorithm/update_renderables.cpp
+++ b/test/algorithm/update_renderables.cpp
@@ -43,14 +43,9 @@ std::ostream& operator<<(std::ostream& os, const CreateTileDataAction& action) {
               << action.tileID.canonical.y << " } } }";
 }
 
-enum Necessity : bool {
-    Optional = false,
-    Required = true,
-};
-
 struct RetainTileDataAction {
     const OverscaledTileID tileID;
-    const Necessity necessity;
+    const Resource::Necessity necessity;
 
     bool operator==(const RetainTileDataAction& rhs) const {
         return tileID == rhs.tileID && necessity == rhs.necessity;
@@ -61,7 +56,7 @@ std::ostream& operator<<(std::ostream& os, const RetainTileDataAction& action) {
     return os << "RetainTileDataAction{ { " << int(action.tileID.overscaledZ) << ", { "
               << int(action.tileID.canonical.z) << ", " << action.tileID.canonical.x << ", "
               << action.tileID.canonical.y << " } }, "
-              << (action.necessity == Required ? "Required" : "Optional") << " }";
+              << (action.necessity == Resource::Necessity::Required ? "Required" : "Optional") << " }";
 }
 
 struct RenderTileAction {
@@ -106,8 +101,8 @@ auto createTileDataFn(ActionLog& log, T& dataTiles) {
 }
 
 auto retainTileDataFn(ActionLog& log) {
-    return [&](auto& tileData, bool required) {
-        log.emplace_back(RetainTileDataAction{ tileData.tileID, required ? Required : Optional });
+    return [&](auto& tileData, Resource::Necessity necessity) {
+        log.emplace_back(RetainTileDataAction{ tileData.tileID, necessity });
     };
 }
 
@@ -135,7 +130,7 @@ TEST(UpdateRenderables, SingleTile) {
                                  source.idealTiles, source.zoomRange, 1);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 1, 1 } }, Found },       // found ideal tile
-                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 1, 1 }, *tile_1_1_1_1 },       // render ideal tile
               }),
               log);
@@ -146,7 +141,7 @@ TEST(UpdateRenderables, SingleTile) {
                                  source.idealTiles, source.zoomRange, 1);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 1, 1 } }, Found },       // found ideal tile
-                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 1, 1 }, *tile_1_1_1_1 },       // render ideal tile
               }),
               log);
@@ -159,7 +154,7 @@ TEST(UpdateRenderables, SingleTile) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 1 } }, NotFound },    // missing ideal tile
                   CreateTileDataAction{ { 1, { 1, 0, 1 } } },           // create ideal tile
-                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 2 } }, NotFound },    // four child tiles
                   GetTileDataAction{ { 2, { 2, 0, 3 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 2 } }, NotFound },    // ...
@@ -167,7 +162,7 @@ TEST(UpdateRenderables, SingleTile) {
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, NotFound },    // parent tile
 
                   GetTileDataAction{ { 1, { 1, 1, 1 } }, Found },       // found ideal tile
-                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 1, 1 }, *tile_1_1_1_1 },       // render found tile
               }),
               log);
@@ -179,17 +174,17 @@ TEST(UpdateRenderables, SingleTile) {
                                  source.idealTiles, source.zoomRange, 1);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 1 } }, Found },       // missing ideal tile
-                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 2 } }, NotFound },    // four child tiles
                   GetTileDataAction{ { 2, { 2, 0, 3 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 2 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 3 } }, NotFound },    // ...
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, NotFound },    // parent tile
                   CreateTileDataAction{ { 0, { 0, 0, 0 } } },           // load parent tile
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
 
                   GetTileDataAction{ { 1, { 1, 1, 1 } }, Found },       // found ideal tile
-                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 1, 1 }, *tile_1_1_1_1 },       // render found tile
               }),
               log);
@@ -202,11 +197,11 @@ TEST(UpdateRenderables, SingleTile) {
                                  source.idealTiles, source.zoomRange, 1);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 1 } }, Found },       // newly added tile
-                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 0, 1 }, *tile_1_1_0_1 },       // render ideal tile
 
                   GetTileDataAction{ { 1, { 1, 1, 1 } }, Found },       // ideal tile
-                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 1, 1 }, *tile_1_1_1_1 },       // render found tile
               }),
               log);
@@ -221,21 +216,21 @@ TEST(UpdateRenderables, SingleTile) {
                                  source.idealTiles, source.zoomRange, 1);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found },       // found tile, not ready
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    // four child tiles
                   GetTileDataAction{ { 2, { 2, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       // parent tile
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   // optional parent tile was already created before, but is not renderable
 
                   GetTileDataAction{ { 1, { 1, 0, 1 } }, Found },       // ideal tile
-                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 0, 1 }, *tile_1_1_0_1 },       // render ideal tile
 
                   GetTileDataAction{ { 1, { 1, 1, 1 } }, Found },       // ideal tile
-                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 1, 1 }, *tile_1_1_1_1 },       // render ideal tile
               }),
               log);
@@ -247,15 +242,15 @@ TEST(UpdateRenderables, SingleTile) {
                                  source.idealTiles, source.zoomRange, 1);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found },       // found tile, now ready
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 0, 0 }, *tile_1_1_0_0 },       //
 
                   GetTileDataAction{ { 1, { 1, 0, 1 } }, Found },       // ideal tile
-                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 0, 1 }, *tile_1_1_0_1 },       //
 
                   GetTileDataAction{ { 1, { 1, 1, 1 } }, Found },       // ideal tile
-                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 1, 1 }, *tile_1_1_1_1 },       //
               }),
               log);
@@ -281,24 +276,24 @@ TEST(UpdateRenderables, UseParentTile) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 1 } }, NotFound },    // missing ideal tile
                   CreateTileDataAction{ { 1, { 1, 0, 1 } } },           //
-                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 2 } }, NotFound },    // child tile
                   GetTileDataAction{ { 2, { 2, 0, 3 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 2 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 3 } }, NotFound },    // ...
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       // parent found!
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 0, 0, 0 }, *tile_0_0_0_0 },       // render parent
                   GetTileDataAction{ { 1, { 1, 1, 0 } }, NotFound },    // missing ideal tile
                   CreateTileDataAction{ { 1, { 1, 1, 0 } } },           //
-                  RetainTileDataAction{ { 1, { 1, 1, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 2, 0 } }, NotFound },    // child tile
                   GetTileDataAction{ { 2, { 2, 2, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 3, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 3, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 1, { 1, 1, 1 } }, NotFound },    // missing tile
                   CreateTileDataAction{ { 1, { 1, 1, 1 } } },           //
-                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 1 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 2, 2 } }, NotFound },    // child tile
                   GetTileDataAction{ { 2, { 2, 2, 3 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 3, 2 } }, NotFound },    // ...
@@ -324,7 +319,7 @@ TEST(UpdateRenderables, DontUseWrongParentTile) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    // missing ideal tile
                   CreateTileDataAction{ { 2, { 2, 0, 0 } } },           //
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 3, { 3, 0, 0 } }, NotFound },    // child tile
                   GetTileDataAction{ { 3, { 3, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 3, { 3, 1, 0 } }, NotFound },    // ...
@@ -341,14 +336,14 @@ TEST(UpdateRenderables, DontUseWrongParentTile) {
                                  source.idealTiles, source.zoomRange, 2);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },       // non-ready ideal tile
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 3, { 3, 0, 0 } }, NotFound },    // child tile
                   GetTileDataAction{ { 3, { 3, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 3, { 3, 1, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 3, { 3, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, NotFound },    // parent tile, missing
                   CreateTileDataAction{ { 1, { 1, 0, 0 } } },           // find optional parent
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, NotFound },    // parent tile, missing
               }),
               log);
@@ -360,25 +355,25 @@ TEST(UpdateRenderables, DontUseWrongParentTile) {
                                  source.idealTiles, source.zoomRange, 2);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },       // non-ready ideal tile
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   // this tile was added by the previous invocation of updateRenderables
                   GetTileDataAction{ { 3, { 3, 0, 0 } }, NotFound },    // child tile
                   GetTileDataAction{ { 3, { 3, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 3, { 3, 1, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 3, { 3, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found },       // parent tile not ready
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, NotFound },    // missing parent tile
 
                   GetTileDataAction{ { 2, { 2, 2, 0 } }, NotFound },    // missing ideal tile
                   CreateTileDataAction{ { 2, { 2, 2, 0 } } },           //
-                  RetainTileDataAction{ { 2, { 2, 2, 0 } }, Required }, //
+                  RetainTileDataAction{ { 2, { 2, 2, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 3, { 3, 4, 0 } }, NotFound },    // child tile
                   GetTileDataAction{ { 3, { 3, 4, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 3, { 3, 5, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 3, { 3, 5, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 1, { 1, 1, 0 } }, Found },       // found parent tile
-                  RetainTileDataAction{ { 1, { 1, 1, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 1, 1, 0 }, *tile_1_1_1_0 },       // render parent tile
               }),
               log);
@@ -405,13 +400,13 @@ TEST(UpdateRenderables, UseParentTileWhenChildNotReady) {
                                  source.idealTiles, source.zoomRange, 1);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 1 } }, Found },       // found, but not ready
-                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 2 } }, NotFound },    // child tile
                   GetTileDataAction{ { 2, { 2, 0, 3 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 2 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 3 } }, NotFound },    // ...
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       // parent tile, ready
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 0, 0, 0 }, *tile_0_0_0_0 },       // render parent tile
               }),
               log);
@@ -423,7 +418,7 @@ TEST(UpdateRenderables, UseParentTileWhenChildNotReady) {
                                  source.idealTiles, source.zoomRange, 1);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 1 } }, Found },       // found and ready
-                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 0, 1 }, *tile_1_1_0_1 },       // render ideal tile
               }),
               log);
@@ -451,17 +446,17 @@ TEST(UpdateRenderables, UseOverlappingParentTile) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, NotFound },    // ideal tile not found
                   CreateTileDataAction{ { 1, { 1, 0, 0 } } },           //
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    // child tile
                   GetTileDataAction{ { 2, { 2, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       // parent tile found
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 0, 0, 0 }, *tile_0_0_0_0 },       //
 
                   GetTileDataAction{ { 1, { 1, 0, 1 } }, Found },       // ideal tile found
-                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 1 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 1, 0, 1 }, *tile_1_1_0_1 },       //
               }),
               log);
@@ -487,13 +482,13 @@ TEST(UpdateRenderables, UseChildTiles) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, NotFound },    // ideal tile, missing
                   CreateTileDataAction{ { 0, { 0, 0, 0 } } },           //
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found },       // child tile found
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 1, 0, 0 }, *tile_1_1_0_0 },       // render child tile
                   GetTileDataAction{ { 1, { 1, 0, 1 } }, NotFound },    // child tile not found
                   GetTileDataAction{ { 1, { 1, 1, 0 } }, Found },       // child tile found
-                  RetainTileDataAction{ { 1, { 1, 1, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 1, 1, 0 }, *tile_1_1_1_0 },       // render child tile
                   GetTileDataAction{ { 1, { 1, 1, 1 } }, NotFound },    // child tile not found
                   // no parent tile of 0 to consider
@@ -521,15 +516,15 @@ TEST(UpdateRenderables, PreferChildTiles) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, NotFound },    // ideal tile, not found
                   CreateTileDataAction{ { 1, { 1, 0, 0 } } },           //
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },       // child tile, found
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 0, 0 }, *tile_2_2_0_0 },       //
                   GetTileDataAction{ { 2, { 2, 0, 1 } }, NotFound },    // child tile, not found
                   GetTileDataAction{ { 2, { 2, 1, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       // parent tile, found
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 0, 0, 0 }, *tile_0_0_0_0 },       //
               }),
               log);
@@ -544,17 +539,17 @@ TEST(UpdateRenderables, PreferChildTiles) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found }, // ideal tile, not ready
                   // ideal tile was added in previous invocation, but is not yet ready
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },       // child tile, found
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 0, 0 }, *tile_2_2_0_0 },       //
                   GetTileDataAction{ { 2, { 2, 0, 1 } }, Found },       // ...
-                  RetainTileDataAction{ { 2, { 2, 0, 1 } }, Optional }, // ...
+                  RetainTileDataAction{ { 2, { 2, 0, 1 } }, Resource::Necessity::Optional }, // ...
                   RenderTileAction{ { 2, 0, 1 }, *tile_2_2_0_1 },       //
                   GetTileDataAction{ { 2, { 2, 1, 0 } }, NotFound },    // child tile, not found
                   GetTileDataAction{ { 2, { 2, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       // parent tile, found
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 0, 0, 0 }, *tile_0_0_0_0 },       //
               }),
               log);
@@ -567,19 +562,19 @@ TEST(UpdateRenderables, PreferChildTiles) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found }, // ideal tile, not ready
                   // ideal tile was added in first invocation, but is not yet ready
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },       // child tile, found
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 0, 0 }, *tile_2_2_0_0 },       //
                   GetTileDataAction{ { 2, { 2, 0, 1 } }, Found },       // ...
-                  RetainTileDataAction{ { 2, { 2, 0, 1 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 1 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 0, 1 }, *tile_2_2_0_1 },       //
                   GetTileDataAction{ { 2, { 2, 1, 0 } }, Found },       // ...
-                  RetainTileDataAction{ { 2, { 2, 1, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 1, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 1, 0 }, *tile_2_2_1_0 },       //
                   GetTileDataAction{ { 2, { 2, 1, 1 } }, NotFound },    // child tile, not found
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       // parent tile, found
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 0, 0, 0 }, *tile_0_0_0_0 },       //
               }),
               log);
@@ -593,18 +588,18 @@ TEST(UpdateRenderables, PreferChildTiles) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found }, // ideal tile, not ready
                   // ideal tile was added in first invocation, but is not yet ready
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },       // child tile, found
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 0, 0 }, *tile_2_2_0_0 },       //
                   GetTileDataAction{ { 2, { 2, 0, 1 } }, Found },       // ...
-                  RetainTileDataAction{ { 2, { 2, 0, 1 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 1 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 0, 1 }, *tile_2_2_0_1 },       //
                   GetTileDataAction{ { 2, { 2, 1, 0 } }, Found },       // ...
-                  RetainTileDataAction{ { 2, { 2, 1, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 1, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 1, 0 }, *tile_2_2_1_0 },       //
                   GetTileDataAction{ { 2, { 2, 1, 1 } }, Found },       // ...
-                  RetainTileDataAction{ { 2, { 2, 1, 1 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 1, 1 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 1, 1 }, *tile_2_2_1_1 },       //
               }),
               log);
@@ -631,15 +626,15 @@ TEST(UpdateRenderables, UseParentAndChildTiles) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, NotFound },    // ideal tile, missing
                   CreateTileDataAction{ { 1, { 1, 0, 0 } } },           //
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },       // child tile
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 0, 0 }, *tile_2_2_0_0 },       //
                   GetTileDataAction{ { 2, { 2, 0, 1 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 1, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 1, 1 } }, NotFound },    //
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       // parent tile
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 0, 0, 0 }, *tile_0_0_0_0 },       //
               }),
               log);
@@ -651,13 +646,13 @@ TEST(UpdateRenderables, UseParentAndChildTiles) {
                                  source.idealTiles, source.zoomRange, 1);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 0, 1 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 1, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 1, 1 } }, NotFound },    //
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       // parent tile
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 0, 0, 0 }, *tile_0_0_0_0 },       //
               }),
               log);
@@ -682,7 +677,7 @@ TEST(UpdateRenderables, DontUseTilesLowerThanMinzoom) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    // ideal tile, missing
                   CreateTileDataAction{ { 2, { 2, 0, 0 } } },           //
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 3, { 3, 0, 0 } }, NotFound },    //
                   GetTileDataAction{ { 3, { 3, 0, 1 } }, NotFound },    //
                   GetTileDataAction{ { 3, { 3, 1, 0 } }, NotFound },    //
@@ -712,7 +707,7 @@ TEST(UpdateRenderables, UseOverzoomedTileAfterMaxzoom) {
         ActionLog({
             GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    // ideal tile, missing
             CreateTileDataAction{ { 2, { 2, 0, 0 } } },           //
-            RetainTileDataAction{ { 2, { 2, 0, 0 } }, Required }, //
+            RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Required }, //
             GetTileDataAction{ { 3, { 2, 0, 0 } }, NotFound },    // overzoomed tile, not children!
             GetTileDataAction{ { 1, { 1, 0, 0 } }, NotFound },    //
             GetTileDataAction{ { 0, { 0, 0, 0 } }, NotFound },    //
@@ -727,11 +722,11 @@ TEST(UpdateRenderables, UseOverzoomedTileAfterMaxzoom) {
     EXPECT_EQ(
         ActionLog({
             GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },       // ideal tile, missing
-            RetainTileDataAction{ { 2, { 2, 0, 0 } }, Required }, //
+            RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Required }, //
             GetTileDataAction{ { 3, { 2, 0, 0 } }, NotFound },    // overzoomed tile, not children!
             GetTileDataAction{ { 1, { 1, 0, 0 } }, NotFound },    //
             CreateTileDataAction{ { 1, { 1, 0, 0 } } },           //
-            RetainTileDataAction{ { 1, { 1, 0, 0 } }, Optional }, //
+            RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Optional }, //
             GetTileDataAction{ { 0, { 0, 0, 0 } }, NotFound },    //
         }),
         log);
@@ -745,10 +740,10 @@ TEST(UpdateRenderables, UseOverzoomedTileAfterMaxzoom) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 3, { 2, 0, 0 } }, NotFound },    // ideal tile, missing
                   CreateTileDataAction{ { 3, { 2, 0, 0 } } },           //
-                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 4, { 2, 0, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },       //
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 0, 0 }, *tile_2_2_0_0 },       //
               }),
               log);
@@ -761,7 +756,7 @@ TEST(UpdateRenderables, UseOverzoomedTileAfterMaxzoom) {
                                  source.idealTiles, source.zoomRange, 3);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 3, { 2, 0, 0 } }, Found },       //
-                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 2, 0, 0 }, *tile_3_2_0_0 },       //
               }),
               log);
@@ -772,7 +767,7 @@ TEST(UpdateRenderables, UseOverzoomedTileAfterMaxzoom) {
                                  source.idealTiles, source.zoomRange, 2);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },       //
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 2, 0, 0 }, *tile_2_2_0_0 },       //
               }),
               log);
@@ -788,9 +783,9 @@ TEST(UpdateRenderables, UseOverzoomedTileAfterMaxzoom) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    //
                   CreateTileDataAction{ { 2, { 2, 0, 0 } } },           //
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 3, { 2, 0, 0 } }, Found },       // use overzoomed tile!
-                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 0, 0 }, *tile_3_2_0_0 },       //
               }),
               log);
@@ -814,7 +809,7 @@ TEST(UpdateRenderables, AscendToNonOverzoomedTiles) {
                                  source.idealTiles, source.zoomRange, 3);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 3, { 2, 0, 0 } }, Found },       //
-                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   RenderTileAction{ { 2, 0, 0 }, *tile_3_2_0_0 },       //
               }),
               log);
@@ -830,10 +825,10 @@ TEST(UpdateRenderables, AscendToNonOverzoomedTiles) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 3, { 2, 0, 0 } }, NotFound },    //
                   CreateTileDataAction{ { 3, { 2, 0, 0 } } },           //
-                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 4, { 2, 0, 0 } }, NotFound }, // prefer using a child first
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },    //
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 2, 0, 0 }, *tile_2_2_0_0 },       //
               }),
               log);
@@ -848,11 +843,11 @@ TEST(UpdateRenderables, AscendToNonOverzoomedTiles) {
                                  source.idealTiles, source.zoomRange, 3);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 3, { 2, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 4, { 2, 0, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    //
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found },       //
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 1, 0, 0 }, *tile_1_1_0_0 },       //
               }),
               log);
@@ -864,13 +859,13 @@ TEST(UpdateRenderables, AscendToNonOverzoomedTiles) {
                                  source.idealTiles, source.zoomRange, 3);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 3, { 2, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 3, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 4, { 2, 0, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    //
                   CreateTileDataAction{ { 2, { 2, 0, 0 } } },           //
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found },       //
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 1, 0, 0 }, *tile_1_1_0_0 },       //
               }),
               log);
@@ -892,7 +887,7 @@ TEST(UpdateRenderables, DoNotAscendMultipleTimesIfNotFound) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 8, { 8, 0, 0 } }, NotFound },    // ideal tile
                   CreateTileDataAction{ { 8, { 8, 0, 0 } } },           //
-                  RetainTileDataAction{ { 8, { 8, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 8, { 8, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 9, { 9, 0, 0 } }, NotFound },    // child tile
                   GetTileDataAction{ { 9, { 9, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 9, { 9, 1, 0 } }, NotFound },    // ...
@@ -908,7 +903,7 @@ TEST(UpdateRenderables, DoNotAscendMultipleTimesIfNotFound) {
 
                   GetTileDataAction{ { 8, { 8, 1, 0 } }, NotFound },    // ideal tile
                   CreateTileDataAction{ { 8, { 8, 1, 0 } } },           //
-                  RetainTileDataAction{ { 8, { 8, 1, 0 } }, Required }, //
+                  RetainTileDataAction{ { 8, { 8, 1, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 9, { 9, 2, 0 } }, NotFound },    // child tile
                   GetTileDataAction{ { 9, { 9, 2, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 9, { 9, 3, 0 } }, NotFound },    // ...
@@ -926,7 +921,7 @@ TEST(UpdateRenderables, DoNotAscendMultipleTimesIfNotFound) {
                                  source.idealTiles, source.zoomRange, 8);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 8, { 8, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 8, { 8, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 8, { 8, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 9, { 9, 0, 0 } }, NotFound },    // child tile
                   GetTileDataAction{ { 9, { 9, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 9, { 9, 1, 0 } }, NotFound },    // ...
@@ -935,11 +930,11 @@ TEST(UpdateRenderables, DoNotAscendMultipleTimesIfNotFound) {
                   GetTileDataAction{ { 6, { 6, 0, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 5, { 5, 0, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 4, { 4, 0, 0 } }, Found },       // stops ascent
-                  RetainTileDataAction{ { 4, { 4, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 4, { 4, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 4, 0, 0 }, *tile_4_0_0_0 },       //
 
                   GetTileDataAction{ { 8, { 8, 1, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 8, { 8, 1, 0 } }, Required }, //
+                  RetainTileDataAction{ { 8, { 8, 1, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 9, { 9, 2, 0 } }, NotFound },    // child tile
                   GetTileDataAction{ { 9, { 9, 2, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 9, { 9, 3, 0 } }, NotFound },    // ...
@@ -966,13 +961,13 @@ TEST(UpdateRenderables, DontRetainUnusedNonIdealTiles) {
                                  source.idealTiles, source.zoomRange, 2);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 3, { 3, 0, 0 } }, NotFound },    //
                   GetTileDataAction{ { 3, { 3, 0, 1 } }, NotFound },    //
                   GetTileDataAction{ { 3, { 3, 1, 0 } }, NotFound },    //
                   GetTileDataAction{ { 3, { 3, 1, 1 } }, NotFound },    //
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found },       // parent tile, not ready
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, NotFound },    //
               }),
               log);
@@ -999,28 +994,28 @@ TEST(UpdateRenderables, WrappedTiles) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 1, { 1, 1, 0 } }, NotFound },    // ideal tile 1/-1/0
                   CreateTileDataAction{ { 1, { 1, 1, 0 } } },           //
-                  RetainTileDataAction{ { 1, { 1, 1, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 2, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 2, 1 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 3, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 3, 1 } }, NotFound },    //
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       //
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 0, -1, 0 }, *tile_0_0_0_0 },      //
 
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, NotFound },    // ideal tile 1/0/0
                   CreateTileDataAction{ { 1, { 1, 0, 0 } } },           //
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 0, 1 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 1, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 1, 1 } }, NotFound },    //
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       //
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 0, 0, 0 }, *tile_0_0_0_0 },       //
 
                   GetTileDataAction{ { 1, { 1, 1, 0 } }, Found },       // ideal tile 1/1/0
-                  RetainTileDataAction{ { 1, { 1, 1, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 1, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 2, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 2, 1 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 3, 0 } }, NotFound },    //
@@ -1028,13 +1023,13 @@ TEST(UpdateRenderables, WrappedTiles) {
                   // do not ascent; 0/0/0 has been rendered already for 1/0/0
 
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, Found },       // ideal tile 1/2/0
-                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 1, { 1, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 0, 1 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 1, 0 } }, NotFound },    //
                   GetTileDataAction{ { 2, { 2, 1, 1 } }, NotFound },    //
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, Found },       //
-                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 0, { 0, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 0, 1, 0 }, *tile_0_0_0_0 },       //
               }),
               log);
@@ -1055,7 +1050,7 @@ TEST(UpdateRenderables, RepeatedRenderWithMissingOptionals) {
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 6, { 6, 0, 0 } }, NotFound },    // ideal tile, not found
                   CreateTileDataAction{ { 6, { 6, 0, 0 } } },           //
-                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 7, { 7, 0, 0 } }, NotFound },    // children
                   GetTileDataAction{ { 7, { 7, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 0 } }, NotFound },    // ...
@@ -1075,7 +1070,7 @@ TEST(UpdateRenderables, RepeatedRenderWithMissingOptionals) {
                                  source.idealTiles, source.zoomRange, 6);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 6, { 6, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 7, { 7, 0, 0 } }, NotFound },    // children
                   GetTileDataAction{ { 7, { 7, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 0 } }, NotFound },    // ...
@@ -1096,14 +1091,14 @@ TEST(UpdateRenderables, RepeatedRenderWithMissingOptionals) {
                                  source.idealTiles, source.zoomRange, 6);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 6, { 6, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 7, { 7, 0, 0 } }, NotFound },    // children
                   GetTileDataAction{ { 7, { 7, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 5, { 5, 0, 0 } }, NotFound },    // ascent
                   CreateTileDataAction{ { 5, { 5, 0, 0 } } },           //
-                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 4, { 4, 0, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 3, { 3, 0, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    // ...
@@ -1118,13 +1113,13 @@ TEST(UpdateRenderables, RepeatedRenderWithMissingOptionals) {
                                  source.idealTiles, source.zoomRange, 6);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 6, { 6, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 7, { 7, 0, 0 } }, NotFound },    // children
                   GetTileDataAction{ { 7, { 7, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 5, { 5, 0, 0 } }, Found },       // ascent
-                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 4, { 4, 0, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 3, { 3, 0, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    // ...
@@ -1140,16 +1135,16 @@ TEST(UpdateRenderables, RepeatedRenderWithMissingOptionals) {
                                  source.idealTiles, source.zoomRange, 6);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 6, { 6, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 7, { 7, 0, 0 } }, NotFound },    // children
                   GetTileDataAction{ { 7, { 7, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 5, { 5, 0, 0 } }, Found },       // ascent
-                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 4, { 4, 0, 0 } }, NotFound },    // ...
                   CreateTileDataAction{ { 4, { 4, 0, 0 } } },           //
-                  RetainTileDataAction{ { 4, { 4, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 4, { 4, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 3, { 3, 0, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, NotFound },    // ...
@@ -1164,18 +1159,18 @@ TEST(UpdateRenderables, RepeatedRenderWithMissingOptionals) {
                                  source.idealTiles, source.zoomRange, 6);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 6, { 6, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 7, { 7, 0, 0 } }, NotFound },    // children
                   GetTileDataAction{ { 7, { 7, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 5, { 5, 0, 0 } }, Found },       // ascent
-                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 4, { 4, 0, 0 } }, Found },       // ...
-                  RetainTileDataAction{ { 4, { 4, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 4, { 4, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 3, { 3, 0, 0 } }, NotFound },    // ...
                   CreateTileDataAction{ { 3, { 3, 0, 0 } } },           //
-                  RetainTileDataAction{ { 3, { 3, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 3, { 3, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, NotFound },    // ...
@@ -1189,20 +1184,20 @@ TEST(UpdateRenderables, RepeatedRenderWithMissingOptionals) {
                                  source.idealTiles, source.zoomRange, 6);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 6, { 6, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 7, { 7, 0, 0 } }, NotFound },    // children
                   GetTileDataAction{ { 7, { 7, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 5, { 5, 0, 0 } }, Found },       // ascent
-                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 4, { 4, 0, 0 } }, Found },       // ...
-                  RetainTileDataAction{ { 4, { 4, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 4, { 4, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 3, { 3, 0, 0 } }, Found },       // ...
-                  RetainTileDataAction{ { 3, { 3, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 3, { 3, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 2, { 2, 0, 0 } }, NotFound },    // ...
                   CreateTileDataAction{ { 2, { 2, 0, 0 } } },           //
-                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 2, { 2, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 1, { 1, 0, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 0, { 0, 0, 0 } }, NotFound },    // ...
               }),
@@ -1216,17 +1211,17 @@ TEST(UpdateRenderables, RepeatedRenderWithMissingOptionals) {
                                  source.idealTiles, source.zoomRange, 6);
     EXPECT_EQ(ActionLog({
                   GetTileDataAction{ { 6, { 6, 0, 0 } }, Found },       // ideal tile, not ready
-                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Required }, //
+                  RetainTileDataAction{ { 6, { 6, 0, 0 } }, Resource::Necessity::Required }, //
                   GetTileDataAction{ { 7, { 7, 0, 0 } }, NotFound },    // children
                   GetTileDataAction{ { 7, { 7, 0, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 0 } }, NotFound },    // ...
                   GetTileDataAction{ { 7, { 7, 1, 1 } }, NotFound },    // ...
                   GetTileDataAction{ { 5, { 5, 0, 0 } }, Found },       // ascent
-                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 5, { 5, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 4, { 4, 0, 0 } }, Found },       // ...
-                  RetainTileDataAction{ { 4, { 4, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 4, { 4, 0, 0 } }, Resource::Necessity::Optional }, //
                   GetTileDataAction{ { 3, { 3, 0, 0 } }, Found },       // ...
-                  RetainTileDataAction{ { 3, { 3, 0, 0 } }, Optional }, //
+                  RetainTileDataAction{ { 3, { 3, 0, 0 } }, Resource::Necessity::Optional }, //
                   RenderTileAction{ { 3, 0, 0 }, *tile_3_3_0_0 },       //
               }),
               log);