Decrease number of memory reallocations

Adds dedicated filtering for cases when only tile keys are required by
the caller.

Relates-To: MINOR
Signed-off-by: Rustam Gamidov <ext-rustam.gamidov@here.com>

Author: rustam-gamidov-here

olp-cpp-sdk-dataservice-read/src/QueryMetadataJob.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2020 HERE Europe B.V.
+ * Copyright (C) 2020-2024 HERE Europe B.V.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -42,7 +42,7 @@ using QueryItemsFunc =
     std::function<QueryResponseType(QueryType, client::CancellationContext)>;
 
 template <typename QueryResponseType>
-using FilterItemsFunc = std::function<QueryResponseType(QueryResponseType)>;
+using FilterItemsFunc = std::function<void(QueryResponseType&)>;
 
 using VectorOfTokens = std::vector<olp::client::CancellationToken>;
 
@@ -99,9 +99,13 @@ class QueryMetadataJob {
     accumulated_statistics_ += GetNetworkStatistics(response);
 
     if (response.IsSuccessful()) {
-      auto items = response.MoveResult();
-      std::move(items.begin(), items.end(),
-                std::inserter(query_result_, query_result_.begin()));
+      if (query_result_.empty()) {
+        query_result_ = response.MoveResult();
+      } else {
+        auto items = response.MoveResult();
+        std::move(items.begin(), items.end(),
+                  std::inserter(query_result_, query_result_.begin()));
+      }
     } else {
       const auto& error = response.GetError();
       if (error.GetErrorCode() == client::ErrorCode::Cancelled) {
@@ -125,7 +129,7 @@ class QueryMetadataJob {
       }
 
       if (filter_) {
-        query_result_ = filter_(std::move(query_result_));
+        filter_(query_result_);
       }
 
       if (query_result_.empty()) {

olp-cpp-sdk-dataservice-read/src/VersionedLayerClientImpl.cpp

@@ -499,11 +499,12 @@ client::CancellationToken VersionedLayerClientImpl::PrefetchTiles(
 
           const bool aggregation_enabled = request.GetDataAggregationEnabled();
 
-          auto filter = [=](repository::SubQuadsResult tiles) mutable {
+          auto filter = [=](repository::SubQuadsResult& tiles) {
             if (request_only_input_tiles) {
-              return repository.FilterTilesByList(request, std::move(tiles));
+              repository.FilterTilesByList(request, tiles);
+            } else {
+              repository.FilterTilesByLevel(request, tiles);
             }
-            return repository.FilterTilesByLevel(request, std::move(tiles));
           };
 
           auto query = [=](geo::TileKey root,
@@ -512,8 +513,13 @@ client::CancellationToken VersionedLayerClientImpl::PrefetchTiles(
                 root, kQuadTreeDepth, version, inner_context);
 
             if (response.IsSuccessful() && aggregation_enabled) {
+              const auto& tiles = response.GetResult();
               auto network_stats = repository.LoadAggregatedSubQuads(
-                  root, filter(response.GetResult()), version, inner_context);
+                  root,
+                  request_only_input_tiles
+                      ? repository.FilterTileKeysByList(request, tiles)
+                      : repository.FilterTileKeysByLevel(request, tiles),
+                  version, inner_context);
 
               // append network statistics
               network_stats += GetNetworkStatistics(response);

olp-cpp-sdk-dataservice-read/src/VolatileLayerClientImpl.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019-2021 HERE Europe B.V.
+ * Copyright (C) 2019-2024 HERE Europe B.V.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -226,11 +226,11 @@ client::CancellationToken VolatileLayerClientImpl::PrefetchTiles(
                                                 inner_context);
         };
 
-        auto filter = [=](repository::SubQuadsResult tiles) mutable {
+        auto filter = [=](repository::SubQuadsResult& tiles) {
           if (request_only_input_tiles) {
-            return repository.FilterTilesByList(request, std::move(tiles));
+            repository.FilterTilesByList(request, tiles);
           } else {
-            return repository.FilterTilesByLevel(request, std::move(tiles));
+            repository.FilterTilesByLevel(request, tiles);
           }
         };
 

olp-cpp-sdk-dataservice-read/src/repositories/PrefetchTilesRepository.cpp

@@ -49,11 +49,14 @@ constexpr std::uint32_t kMaxQuadTreeIndexDepth = 4u;
 SubQuadsResult FlattenTree(const QuadTreeIndex& tree) {
   SubQuadsResult result;
   auto index_data = tree.GetIndexData();
-  std::transform(index_data.begin(), index_data.end(),
-                 std::inserter(result, result.end()),
-                 [](const QuadTreeIndex::IndexData& data) {
-                   return std::make_pair(data.tile_key, data.data_handle);
-                 });
+  for (auto& data : index_data) {
+    const auto it = result.lower_bound(data.tile_key);
+    if (it == result.end() || result.key_comp()(data.tile_key, it->first)) {
+      result.emplace_hint(it, std::piecewise_construct,
+                          std::forward_as_tuple(data.tile_key),
+                          std::forward_as_tuple(std::move(data.data_handle)));
+    }
+  }
   return result;
 }
 
@@ -173,8 +176,8 @@ RootTilesForRequest PrefetchTilesRepository::GetSlicedTiles(
 }
 
 client::NetworkStatistics PrefetchTilesRepository::LoadAggregatedSubQuads(
-    geo::TileKey root, const SubQuadsResult& tiles, std::int64_t version,
-    client::CancellationContext context) {
+    geo::TileKey root, const std::vector<geo::TileKey>& tiles,
+    std::int64_t version, client::CancellationContext context) {
   // if quad tree isn't cached, no reason to download additional quads
   QuadTreeIndex quad_tree;
   client::NetworkStatistics network_stats;
@@ -191,7 +194,7 @@ client::NetworkStatistics PrefetchTilesRepository::LoadAggregatedSubQuads(
   // found in subtiles. In this way we make sure that all tiles within requested
   // tree have aggregated parent downloaded and cached. This may cause
   // additional or duplicate download request.
-  auto root_index = quad_tree.Find(highest_tile_it->first, true);
+  auto root_index = quad_tree.Find(*highest_tile_it, true);
   if (root_index) {
     const auto& aggregated_tile_key = root_index->tile_key;
 
@@ -316,89 +319,113 @@ SubQuadsResponse PrefetchTilesRepository::GetVolatileSubQuads(
   return result;
 }
 
-SubQuadsResult PrefetchTilesRepository::FilterTilesByLevel(
-    const PrefetchTilesRequest& request, SubQuadsResult tiles) {
-  const auto& tile_keys = request.GetTileKeys();
-
-  auto skip_tile = [&](const geo::TileKey& tile_key) {
-    if (tile_key.Level() < request.GetMinLevel()) {
-      return true;
-    }
-
-    if (tile_key.Level() > request.GetMaxLevel()) {
-      return true;
-    }
-
-    return std::find_if(tile_keys.begin(), tile_keys.end(),
-                        [&tile_key](const geo::TileKey& root_key) {
-                          return (root_key.IsParentOf(tile_key) ||
-                                  tile_key.IsParentOf(root_key) ||
-                                  root_key == tile_key);
-                        }) == tile_keys.end();
-  };
+static bool skip_tile(const PrefetchTilesRequest& request,
+                      const geo::TileKey& tile_key) {
+  if (tile_key.Level() < request.GetMinLevel() ||
+      tile_key.Level() > request.GetMaxLevel()) {
+    return true;
+  }
+  for (const geo::TileKey& root_key : request.GetTileKeys()) {
+    if (root_key == tile_key || root_key.IsParentOf(tile_key) ||
+        tile_key.IsParentOf(root_key))
+      return false;
+  }
+  return true;
+}
 
+void PrefetchTilesRepository::FilterTilesByLevel(
+    const PrefetchTilesRequest& request, SubQuadsResult& tiles) const {
   for (auto sub_quad_it = tiles.begin(); sub_quad_it != tiles.end();) {
-    if (skip_tile(sub_quad_it->first)) {
+    if (skip_tile(request, sub_quad_it->first)) {
       sub_quad_it = tiles.erase(sub_quad_it);
     } else {
       ++sub_quad_it;
     }
   }
+}
 
-  return tiles;
+std::vector<geo::TileKey> PrefetchTilesRepository::FilterTileKeysByLevel(
+    const PrefetchTilesRequest& request, const SubQuadsResult& tiles) const {
+  std::vector<geo::TileKey> result;
+  for (const auto& tile : tiles) {
+    if (!skip_tile(request, tile.first)) {
+      result.emplace_back(tile.first);
+    }
+  }
+  return result;
 }
 
-SubQuadsResult PrefetchTilesRepository::FilterTilesByList(
-    const PrefetchTilesRequest& request, SubQuadsResult tiles) {
-  const bool aggregation_enabled = request.GetDataAggregationEnabled();
+void PrefetchTilesRepository::FilterTilesByList(
+    const PrefetchTilesRequest& request, SubQuadsResult& tiles) const {
+  SubQuadsResult result;
 
+  const bool aggregation_enabled = request.GetDataAggregationEnabled();
   const auto& tile_keys = request.GetTileKeys();
 
   if (!aggregation_enabled) {
-    for (auto it = tiles.begin(); it != tiles.end();) {
-      if (std::find(tile_keys.begin(), tile_keys.end(), it->first) ==
-          tile_keys.end()) {
-        it = tiles.erase(it);
-      } else {
-        ++it;
+    for (const auto& tile : tile_keys) {
+      const auto it = tiles.find(tile);
+      auto& new_tile = result[tile];
+      if (it != tiles.end()) {
+        new_tile = std::move(it->second);
+        tiles.erase(it);
       }
     }
+  } else {
+    auto append_tile = [&](const geo::TileKey& key) {
+      const auto it = tiles.find(key);
+      if (it != tiles.end()) {
+        result.emplace(key, std::move(it->second));
+        return true;
+      } else {
+        return result.find(key) != result.end();
+      }
+    };
 
     for (const auto& tile : tile_keys) {
-      if (tiles.find(tile) == tiles.end()) {
-        tiles[tile] = "";
+      auto aggregated_tile = tile;
+
+      while (aggregated_tile.IsValid() && !append_tile(aggregated_tile)) {
+        aggregated_tile = aggregated_tile.Parent();
+      }
+
+      if (!aggregated_tile.IsValid()) {
+        result[tile].clear();  // To generate Not Found error
       }
     }
+  }
+  tiles.swap(result);
+}
 
-  } else {
-    SubQuadsResult result;
+std::vector<geo::TileKey> PrefetchTilesRepository::FilterTileKeysByList(
+    const PrefetchTilesRequest& request, const SubQuadsResult& tiles) const {
+  std::vector<geo::TileKey> result;
 
-    auto append_tile = [&](const geo::TileKey& key) {
-      auto tile_it = tiles.find(key);
-      if (tile_it != tiles.end()) {
-        result[tile_it->first] = tile_it->second;
+  if (!request.GetDataAggregationEnabled()) {
+    result = request.GetTileKeys();
+  } else {
+    auto append_tile = [&tiles, &result](const geo::TileKey& key) {
+      if (tiles.count(key) == 1) {
+        result.emplace_back(key);
         return true;
       } else {
-        return false;
+        return std::find(result.begin(), result.end(), key) != result.end();
       }
     };
 
-    for (const auto& tile : tile_keys) {
+    for (const auto& tile : request.GetTileKeys()) {
       auto aggregated_tile = tile;
 
       while (aggregated_tile.IsValid() && !append_tile(aggregated_tile)) {
         aggregated_tile = aggregated_tile.Parent();
       }
 
       if (!aggregated_tile.IsValid()) {
-        result[tile] = "";  // To generate Not Found error
+        result.emplace_back(tile);  // To generate Not Found error
       }
     }
-
-    tiles.swap(result);
   }
-
-  return tiles;
+  return result;
 }
 
 PrefetchTilesRepository::QuadTreeResponse

olp-cpp-sdk-dataservice-read/src/repositories/PrefetchTilesRepository.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019-2021 HERE Europe B.V.
+ * Copyright (C) 2019-2024 HERE Europe B.V.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,7 @@
 
 #include <map>
 #include <string>
+#include <vector>
 
 #include <olp/core/client/ApiError.h>
 #include <olp/core/client/ApiLookupClient.h>
@@ -71,6 +72,18 @@ class PrefetchTilesRepository {
   RootTilesForRequest GetSlicedTiles(const std::vector<geo::TileKey>& tile_keys,
                                      std::uint32_t min, std::uint32_t max);
 
+  /**
+   * @brief Filters the input tiles according to the request.
+   *
+   * Removes tiles that do not belong to the minimum and maximum levels.
+   * Removes tiles that are not a child or a parent of the requested tiles.
+   *
+   * @param request Your request.
+   * @param tiles The input tiles.
+   */
+  void FilterTilesByLevel(const PrefetchTilesRequest& request,
+                          SubQuadsResult& tiles) const;
+
   /**
    * @brief Filters the input tiles according to the request.
    *
@@ -80,10 +93,10 @@ class PrefetchTilesRepository {
    * @param request Your request.
    * @param tiles The input tiles.
    *
-   * @returns The modified tiles.
+   * @returns Tile keys matching the request.
    */
-  SubQuadsResult FilterTilesByLevel(const PrefetchTilesRequest& request,
-                                    SubQuadsResult tiles);
+  std::vector<geo::TileKey> FilterTileKeysByLevel(
+      const PrefetchTilesRequest& request, const SubQuadsResult& tiles) const;
 
   /**
    * @brief Filters the input tiles according to the request.
@@ -94,15 +107,28 @@ class PrefetchTilesRepository {
    *
    * @param request Your request.
    * @param tiles The input tiles.
+   */
+  void FilterTilesByList(const PrefetchTilesRequest& request,
+                         SubQuadsResult& tiles) const;
+
+  /**
+   * @brief Filters the input tiles according to the request.
+   *
+   * Removes tile keys that are not requested.
+   * Adds tile keys that are missing (to notify you that they are not found).
+   * If aggregated tiles were requested, scans for parents.
    *
-   * @returns The modified tiles.
+   * @param request Your request.
+   * @param tiles The input tiles.
+   *
+   * @returns Tile keys matching the request.
    */
-  SubQuadsResult FilterTilesByList(const PrefetchTilesRequest& request,
-                                   SubQuadsResult tiles);
+  std::vector<geo::TileKey> FilterTileKeysByList(
+      const PrefetchTilesRequest& request, const SubQuadsResult& tiles) const;
 
   client::NetworkStatistics LoadAggregatedSubQuads(
-      geo::TileKey tile, const SubQuadsResult& tiles, std::int64_t version,
-      client::CancellationContext context);
+      geo::TileKey tile, const std::vector<geo::TileKey>& tiles,
+      std::int64_t version, client::CancellationContext context);
 
   SubQuadsResponse GetVersionedSubQuads(geo::TileKey tile, int32_t depth,
                                         std::int64_t version,