--[BE] - Add ability to filter Configuration subconfigs (#2471)

* --add subconfig filtering process.
This function will remove any values and subconfigs from a Configuration that match those found within a passed Configuration.
* --minor naming clarification
* --expand Configuration tests to test filtering; rename test
Test only tests Configurations, so name appropriately

src/esp/bindings/ConfigBindings.cpp

@@ -152,7 +152,7 @@ void initConfigBindings(py::module& m) {
           R"(Returns whether or not this Configuration has the passed key. Does not check subconfigurations.)",
           "key"_a)
       .def(
-          "has_key_to_type", &Configuration::hasKeyOfType,
+          "has_key_to_type", &Configuration::hasKeyToValOfType,
           R"(Returns whether passed key points to a value of specified ConfigValType)",
           "key"_a, "value_type"_a)
       .def(

src/esp/core/Configuration.cpp

@@ -783,6 +783,52 @@ std::vector<std::string> Configuration::findValue(
   return breadcrumbs;
 }
 
+void Configuration::overwriteWithConfig(
+    const std::shared_ptr<const Configuration>& src) {
+  if (src->getNumEntries() == 0) {
+    return;
+  }
+  // copy every element over from src
+  for (const auto& elem : src->valueMap_) {
+    valueMap_[elem.first] = elem.second;
+  }
+  // merge subconfigs
+  for (const auto& subConfig : src->configMap_) {
+    const auto name = subConfig.first;
+    // make if DNE and merge src subconfig
+    addOrEditSubgroup<Configuration>(name).first->second->overwriteWithConfig(
+        subConfig.second);
+  }
+}  // Configuration::overwriteWithConfig
+
+void Configuration::filterFromConfig(
+    const std::shared_ptr<const Configuration>& src) {
+  if (src->getNumEntries() == 0) {
+    return;
+  }
+  // filter out every element that is present with the same value in both src
+  // and this.
+  for (const auto& elem : src->valueMap_) {
+    ValueMapType::const_iterator mapIter = valueMap_.find(elem.first);
+    // if present and has the same data, erase this configuration's data
+    if ((mapIter != valueMap_.end()) && (mapIter->second == elem.second)) {
+      valueMap_.erase(mapIter);
+    }
+  }
+  // repeat process on all subconfigs of src that are present in this.
+  for (const auto& subConfig : src->configMap_) {
+    // find if this has subconfig of same name
+    ConfigMapType::iterator mapIter = configMap_.find(subConfig.first);
+    if (mapIter != configMap_.end()) {
+      mapIter->second->filterFromConfig(subConfig.second);
+      // remove the subconfig if it has no entries after filtering
+      if (mapIter->second->getNumEntries() == 0) {
+        configMap_.erase(mapIter);
+      }
+    }
+  }
+}  // Configuration::filterFromConfig
+
 Configuration& Configuration::operator=(const Configuration& otr) {
   if (this != &otr) {
     configMap_.clear();

src/esp/core/Configuration.h

@@ -697,7 +697,7 @@ class Configuration {
       : configMap_(std::move(otr.configMap_)),
         valueMap_(std::move(otr.valueMap_)) {}  // move ctor
 
-  // virtual destructor set to that pybind11 recognizes attributes inheritance
+  // virtual destructor set so that pybind11 recognizes attributes inheritance
   // from Configuration to be polymorphic
   virtual ~Configuration() = default;
 
@@ -1163,7 +1163,8 @@ class Configuration {
    * @param desiredType the @ref ConfigValType to compare the value's type to
    * @return Whether @p key references a value that is of @p desiredType.
    */
-  bool hasKeyOfType(const std::string& key, ConfigValType desiredType) {
+  bool hasKeyToValOfType(const std::string& key,
+                         ConfigValType desiredType) const {
     ValueMapType::const_iterator mapIter = valueMap_.find(key);
     return (mapIter != valueMap_.end() &&
             (mapIter->second.getType() == desiredType));
@@ -1247,7 +1248,6 @@ class Configuration {
    * @return A pointer to a copy of the Configuration having the requested
    * name, cast to the appropriate type, or nullptr if not found.
    */
-
   template <typename T>
   std::shared_ptr<T> getSubconfigCopy(const std::string& cfgName) const {
     static_assert(std::is_base_of<Configuration, T>::value,
@@ -1371,27 +1371,24 @@ class Configuration {
 
   /**
    * @brief Merges Configuration pointed to by @p src into this
-   * Configuration, including all subconfigs.  Passed config overwrites
+   * Configuration, including all subconfigs. Passed config overwrites
    * existing data in this config.
    * @param src The source of Configuration data we wish to merge into this
    * Configuration.
    */
-  void overwriteWithConfig(const std::shared_ptr<const Configuration>& src) {
-    if (src->getNumEntries() == 0) {
-      return;
-    }
-    // copy every element over from src
-    for (const auto& elem : src->valueMap_) {
-      valueMap_[elem.first] = elem.second;
-    }
-    // merge subconfigs
-    for (const auto& subConfig : src->configMap_) {
-      const auto name = subConfig.first;
-      // make if DNE and merge src subconfig
-      addOrEditSubgroup<Configuration>(name).first->second->overwriteWithConfig(
-          subConfig.second);
-    }
-  }
+  void overwriteWithConfig(const std::shared_ptr<const Configuration>& src);
+
+  /**
+   * @brief Performs the opposite operation to @ref Configuration::overwriteWithConfig.
+   * All values and subconfigs in the passed Configuration will be removed from
+   * this config unless the data they hold is different. Any empty subconfigs
+   * will be removed as well.
+   *
+   * @param src The source of Configuration data we wish to prune from this
+   * Configuration.
+   */
+
+  void filterFromConfig(const std::shared_ptr<const Configuration>& src);
 
   /**
    * @brief Returns a const iterator across the map of values.

src/tests/CMakeLists.txt

@@ -74,7 +74,7 @@ if(MagnumPlugins_KtxImageConverter_FOUND)
   target_link_libraries(GfxBatchRendererTest PRIVATE MagnumPlugins::KtxImageConverter)
 endif()
 
-corrade_add_test(CoreTest CoreTest.cpp LIBRARIES core io)
+corrade_add_test(ConfigurationTest ConfigurationTest.cpp LIBRARIES core io)
 
 corrade_add_test(CullingTest CullingTest.cpp LIBRARIES gfx)
 target_include_directories(CullingTest PRIVATE ${CMAKE_CURRENT_BINARY_DIR})