Config: Flatten structures

Originally, Layer contained a std::map of Sections, which containted a std::map
containing the (key, value) pairs. Here we flattern this structure so that only
one std::map is required, reducing the number of indirections required and
vastly simplifying the code.

6 files changed, 112 insertions, 417 deletions

diff --git a/Source/Core/Common/Config/Config.cpp b/Source/Core/Common/Config/Config.cpp
index abb2304749..a3504f80d2 100644
--- a/Source/Core/Common/Config/Config.cpp
+++ b/Source/Core/Common/Config/Config.cpp
@@ -133,7 +133,7 @@ LayerType GetActiveLayerForConfig(const ConfigLocation& config)
     if (!LayerExists(layer))
       continue;
 
-    if (GetLayer(layer)->Exists(config.system, config.section, config.key))
+    if (GetLayer(layer)->Exists(config))
       return layer;
   }
 
diff --git a/Source/Core/Common/Config/Config.h b/Source/Core/Common/Config/Config.h
index 69eac72203..3536f5677c 100644
--- a/Source/Core/Common/Config/Config.h
+++ b/Source/Core/Common/Config/Config.h
@@ -12,7 +12,6 @@
 #include "Common/Config/ConfigInfo.h"
 #include "Common/Config/Enums.h"
 #include "Common/Config/Layer.h"
-#include "Common/Config/Section.h"
 
 namespace Config
 {
diff --git a/Source/Core/Common/Config/Layer.cpp b/Source/Core/Common/Config/Layer.cpp
index a3912281f5..d4f9e7c633 100644
--- a/Source/Core/Common/Config/Layer.cpp
+++ b/Source/Core/Common/Config/Layer.cpp
@@ -8,10 +8,47 @@
 
 #include "Common/Config/Config.h"
 #include "Common/Config/Layer.h"
-#include "Common/Config/Section.h"
 
 namespace Config
 {
+namespace detail
+{
+std::string ValueToString(u16 value)
+{
+  return StringFromFormat("0x%04x", value);
+}
+
+std::string ValueToString(u32 value)
+{
+  return StringFromFormat("0x%08x", value);
+}
+
+std::string ValueToString(float value)
+{
+  return StringFromFormat("%#.9g", value);
+}
+
+std::string ValueToString(double value)
+{
+  return StringFromFormat("%#.17g", value);
+}
+
+std::string ValueToString(int value)
+{
+  return std::to_string(value);
+}
+
+std::string ValueToString(bool value)
+{
+  return StringFromBool(value);
+}
+
+std::string ValueToString(const std::string& value)
+{
+  return value;
+}
+}
+
 ConfigLayerLoader::ConfigLayerLoader(LayerType layer) : m_layer(layer)
 {
 }
@@ -38,56 +75,44 @@ Layer::~Layer()
   Save();
 }
 
-bool Layer::Exists(System system, const std::string& section_name, const std::string& key)
-{
-  Section* section = GetSection(system, section_name);
-  if (!section)
-    return false;
-  return section->Exists(key);
-}
-
-bool Layer::DeleteKey(System system, const std::string& section_name, const std::string& key)
+bool Layer::Exists(const ConfigLocation& location) const
 {
-  Section* section = GetSection(system, section_name);
-  if (!section)
-    return false;
-  return section->Delete(key);
+  const auto iter = m_map.find(location);
+  return iter != m_map.end() && iter->second.has_value();
 }
 
-Section* Layer::GetSection(System system, const std::string& section_name)
+bool Layer::DeleteKey(const ConfigLocation& location)
 {
-  for (auto& section : m_sections[system])
-    if (!strcasecmp(section->m_name.c_str(), section_name.c_str()))
-      return section.get();
-  return nullptr;
+  m_is_dirty = true;
+  bool had_value = m_map[location].has_value();
+  m_map[location].reset();
+  return had_value;
 }
 
-Section* Layer::GetOrCreateSection(System system, const std::string& section_name)
+void Layer::DeleteAllKeys()
 {
-  Section* section = GetSection(system, section_name);
-  if (!section)
+  m_is_dirty = true;
+  for (auto& pair : m_map)
   {
-    m_sections[system].emplace_back(std::make_unique<Section>(m_layer, system, section_name));
-    section = m_sections[system].back().get();
+    pair.second.reset();
   }
-  return section;
 }
 
 void Layer::Load()
 {
   if (m_loader)
     m_loader->Load(this);
-  ClearDirty();
+  m_is_dirty = false;
   InvokeConfigChangedCallbacks();
 }
 
 void Layer::Save()
 {
-  if (!m_loader || !IsDirty())
+  if (!m_loader || !m_is_dirty)
     return;
 
   m_loader->Save(this);
-  ClearDirty();
+  m_is_dirty = false;
   InvokeConfigChangedCallbacks();
 }
 
@@ -98,22 +123,6 @@ LayerType Layer::GetLayer() const
 
 const LayerMap& Layer::GetLayerMap() const
 {
-  return m_sections;
-}
-
-bool Layer::IsDirty() const
-{
-  return std::any_of(m_sections.begin(), m_sections.end(), [](const auto& system) {
-    return std::any_of(system.second.begin(), system.second.end(),
-                       [](const auto& section) { return section->IsDirty(); });
-  });
-}
-
-void Layer::ClearDirty()
-{
-  std::for_each(m_sections.begin(), m_sections.end(), [](auto& system) {
-    std::for_each(system.second.begin(), system.second.end(),
-                  [](auto& section) { section->ClearDirty(); });
-  });
+  return m_map;
 }
 }
diff --git a/Source/Core/Common/Config/Layer.h b/Source/Core/Common/Config/Layer.h
index ac5b5c3e78..eb2a6bafca 100644
--- a/Source/Core/Common/Config/Layer.h
+++ b/Source/Core/Common/Config/Layer.h
@@ -6,18 +6,47 @@
 
 #include <map>
 #include <memory>
+#include <optional>
 #include <string>
 #include <vector>
 
+#include "Common/Config/ConfigInfo.h"
 #include "Common/Config/Enums.h"
-#include "Common/Config/Section.h"
+#include "Common/StringUtil.h"
 
 namespace Config
 {
+namespace detail
+{
+std::string ValueToString(u16 value);
+std::string ValueToString(u32 value);
+std::string ValueToString(float value);
+std::string ValueToString(double value);
+std::string ValueToString(int value);
+std::string ValueToString(bool value);
+std::string ValueToString(const std::string& value);
+
+template <typename T>
+std::optional<T> TryParse(const std::string& str_value)
+{
+  T value;
+  if (!::TryParse(str_value, &value))
+    return std::nullopt;
+  return value;
+}
+
+template <>
+inline std::optional<std::string> TryParse(const std::string& str_value)
+{
+  return str_value;
+}
+}
+
 template <typename T>
 struct ConfigInfo;
 
-using LayerMap = std::map<System, std::vector<std::unique_ptr<Section>>>;
+class Layer;
+using LayerMap = std::map<ConfigLocation, std::optional<std::string>>;
 
 class ConfigLayerLoader
 {
@@ -41,32 +70,40 @@ public:
   virtual ~Layer();
 
   // Convenience functions
-  bool Exists(System system, const std::string& section_name, const std::string& key);
-  bool DeleteKey(System system, const std::string& section_name, const std::string& key);
+  bool Exists(const ConfigLocation& location) const;
+  bool DeleteKey(const ConfigLocation& location);
+  void DeleteAllKeys();
+
   template <typename T>
-  bool GetIfExists(System system, const std::string& section_name, const std::string& key, T* value)
+  T Get(const ConfigInfo<T>& config_info)
   {
-    if (Exists(system, section_name, key))
-      return GetOrCreateSection(system, section_name)->Get(key, value);
-
-    return false;
+    return Get<T>(config_info.location).value_or(config_info.default_value);
   }
 
-  virtual Section* GetSection(System system, const std::string& section_name);
-  virtual Section* GetOrCreateSection(System system, const std::string& section_name);
-
   template <typename T>
-  T Get(const ConfigInfo<T>& config_info)
+  std::optional<T> Get(const ConfigLocation& location)
   {
-    return GetOrCreateSection(config_info.location.system, config_info.location.section)
-        ->template Get<T>(config_info.location.key, config_info.default_value);
+    const std::optional<std::string>& str_value = m_map[location];
+    if (!str_value)
+      return std::nullopt;
+    return detail::TryParse<T>(*str_value);
   }
 
   template <typename T>
   void Set(const ConfigInfo<T>& config_info, const T& value)
   {
-    GetOrCreateSection(config_info.location.system, config_info.location.section)
-        ->Set(config_info.location.key, value);
+    Set<T>(config_info.location, value);
+  }
+
+  template <typename T>
+  void Set(const ConfigLocation& location, const T& value)
+  {
+    const std::string new_value = detail::ValueToString(value);
+    std::optional<std::string>& current_value = m_map[location];
+    if (current_value == new_value)
+      return;
+    m_is_dirty = true;
+    current_value = new_value;
   }
 
   // Explicit load and save of layers
@@ -77,11 +114,9 @@ public:
   const LayerMap& GetLayerMap() const;
 
 protected:
-  bool IsDirty() const;
-  void ClearDirty();
-
-  LayerMap m_sections;
+  bool m_is_dirty = false;
+  LayerMap m_map;
   const LayerType m_layer;
   std::unique_ptr<ConfigLayerLoader> m_loader;
 };
-} // namespace Config
+}
diff --git a/Source/Core/Common/Config/Section.cpp b/Source/Core/Common/Config/Section.cpp
deleted file mode 100644
index 12adff2b1f..0000000000
--- a/Source/Core/Common/Config/Section.cpp
+++ /dev/null
@@ -1,249 +0,0 @@
-// Copyright 2017 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
-
-#include <cstddef>
-#include <map>
-#include <memory>
-
-#include "Common/Assert.h"
-#include "Common/Config/Config.h"
-#include "Common/Config/Layer.h"
-#include "Common/Config/Section.h"
-#include "Common/StringUtil.h"
-
-namespace Config
-{
-const std::string& Section::NULL_STRING = "";
-
-Section::Section(LayerType layer, System system, const std::string& name)
-    : m_layer(layer), m_system(system), m_name(name)
-{
-}
-
-bool Section::Exists(const std::string& key) const
-{
-  return m_values.find(key) != m_values.end();
-}
-
-bool Section::Delete(const std::string& key)
-{
-  auto it = m_values.find(key);
-  if (it == m_values.end())
-    return false;
-
-  m_values.erase(it);
-
-  m_deleted_keys.push_back(key);
-  m_dirty = true;
-  return true;
-}
-
-void Section::Set(const std::string& key, const std::string& value)
-{
-  auto it = m_values.find(key);
-  if (it != m_values.end() && it->second != value)
-  {
-    it->second = value;
-    m_dirty = true;
-  }
-  else if (it == m_values.end())
-  {
-    m_values[key] = value;
-    m_dirty = true;
-  }
-}
-
-void Section::Set(const std::string& key, u16 newValue)
-{
-  Section::Set(key, StringFromFormat("0x%04x", newValue));
-}
-
-void Section::Set(const std::string& key, u32 newValue)
-{
-  Section::Set(key, StringFromFormat("0x%08x", newValue));
-}
-
-void Section::Set(const std::string& key, float newValue)
-{
-  Section::Set(key, StringFromFormat("%#.9g", newValue));
-}
-
-void Section::Set(const std::string& key, double newValue)
-{
-  Section::Set(key, StringFromFormat("%#.17g", newValue));
-}
-
-void Section::Set(const std::string& key, int newValue)
-{
-  Section::Set(key, std::to_string(newValue));
-}
-
-void Section::Set(const std::string& key, bool newValue)
-{
-  Section::Set(key, StringFromBool(newValue));
-}
-
-void Section::Set(const std::string& key, const std::string& newValue,
-                  const std::string& defaultValue)
-{
-  if (newValue != defaultValue)
-    Set(key, newValue);
-  else
-    Delete(key);
-}
-
-void Section::SetLines(const std::vector<std::string>& lines)
-{
-  m_lines = lines;
-  m_dirty = true;
-}
-
-bool Section::Get(const std::string& key, std::string* value,
-                  const std::string& default_value) const
-{
-  const auto& it = m_values.find(key);
-  if (it != m_values.end())
-  {
-    *value = it->second;
-    return true;
-  }
-  else if (&default_value != &NULL_STRING)
-  {
-    *value = default_value;
-    return true;
-  }
-
-  return false;
-}
-
-bool Section::Get(const std::string& key, int* value, int defaultValue) const
-{
-  std::string temp;
-  bool retval = Get(key, &temp);
-
-  if (retval && TryParse(temp, value))
-    return true;
-
-  *value = defaultValue;
-  return false;
-}
-
-bool Section::Get(const std::string& key, u16* value, u16 defaultValue) const
-{
-  std::string temp;
-  bool retval = Get(key, &temp);
-
-  if (retval && TryParse(temp, value))
-    return true;
-
-  *value = defaultValue;
-  return false;
-}
-
-bool Section::Get(const std::string& key, u32* value, u32 defaultValue) const
-{
-  std::string temp;
-  bool retval = Get(key, &temp);
-
-  if (retval && TryParse(temp, value))
-    return true;
-
-  *value = defaultValue;
-  return false;
-}
-
-bool Section::Get(const std::string& key, bool* value, bool defaultValue) const
-{
-  std::string temp;
-  bool retval = Get(key, &temp);
-
-  if (retval && TryParse(temp, value))
-    return true;
-
-  *value = defaultValue;
-  return false;
-}
-
-bool Section::Get(const std::string& key, float* value, float defaultValue) const
-{
-  std::string temp;
-  bool retval = Get(key, &temp);
-
-  if (retval && TryParse(temp, value))
-    return true;
-
-  *value = defaultValue;
-  return false;
-}
-
-bool Section::Get(const std::string& key, double* value, double defaultValue) const
-{
-  std::string temp;
-  bool retval = Get(key, &temp);
-
-  if (retval && TryParse(temp, value))
-    return true;
-
-  *value = defaultValue;
-  return false;
-}
-
-// Return a list of all lines in a section
-bool Section::GetLines(std::vector<std::string>* lines, const bool remove_comments) const
-{
-  lines->clear();
-
-  for (std::string line : m_lines)
-  {
-    line = StripSpaces(line);
-
-    if (remove_comments)
-    {
-      size_t commentPos = line.find('#');
-      if (commentPos == 0)
-      {
-        continue;
-      }
-
-      if (commentPos != std::string::npos)
-      {
-        line = StripSpaces(line.substr(0, commentPos));
-      }
-    }
-
-    lines->push_back(line);
-  }
-
-  return true;
-}
-
-bool Section::HasLines() const
-{
-  return !m_lines.empty();
-}
-
-const std::string& Section::GetName() const
-{
-  return m_name;
-}
-
-const SectionValueMap& Section::GetValues() const
-{
-  return m_values;
-}
-
-const std::vector<std::string>& Section::GetDeletedKeys() const
-{
-  return m_deleted_keys;
-}
-
-bool Section::IsDirty() const
-{
-  return m_dirty;
-}
-void Section::ClearDirty()
-{
-  m_dirty = false;
-}
-}
diff --git a/Source/Core/Common/Config/Section.h b/Source/Core/Common/Config/Section.h
deleted file mode 100644
index 592b791722..0000000000
--- a/Source/Core/Common/Config/Section.h
+++ /dev/null
@@ -1,99 +0,0 @@
-// Copyright 2017 Dolphin Emulator Project
-// Licensed under GPLv2+
-// Refer to the license.txt file included.
-
-#pragma once
-
-#include <map>
-#include <string>
-#include <vector>
-
-// XXX: Purely for case insensitive compare
-#include "Common/CommonTypes.h"
-#include "Common/Config/Enums.h"
-#include "Common/IniFile.h"
-
-namespace Config
-{
-class Layer;
-class ConfigLayerLoader;
-
-using SectionValueMap = std::map<std::string, std::string, CaseInsensitiveStringCompare>;
-
-class Section
-{
-  friend Layer;
-  friend ConfigLayerLoader;
-
-public:
-  Section(LayerType layer, System system, const std::string& name);
-  virtual ~Section() = default;
-
-  virtual bool Exists(const std::string& key) const;
-  bool Delete(const std::string& key);
-
-  // Setters
-  virtual void Set(const std::string& key, const std::string& value);
-
-  void Set(const std::string& key, u16 newValue);
-  void Set(const std::string& key, u32 newValue);
-  void Set(const std::string& key, float newValue);
-  void Set(const std::string& key, double newValue);
-  void Set(const std::string& key, int newValue);
-  void Set(const std::string& key, bool newValue);
-
-  // Setters with default values
-  void Set(const std::string& key, const std::string& newValue, const std::string& defaultValue);
-  template <typename T>
-  void Set(const std::string& key, T newValue, const T defaultValue)
-  {
-    if (newValue != defaultValue)
-      Set(key, newValue);
-    else
-      Delete(key);
-  }
-
-  // Getters
-  virtual bool Get(const std::string& key, std::string* value,
-                   const std::string& default_value = NULL_STRING) const;
-
-  bool Get(const std::string& key, int* value, int defaultValue = 0) const;
-  bool Get(const std::string& key, u16* value, u16 defaultValue = 0) const;
-  bool Get(const std::string& key, u32* value, u32 defaultValue = 0) const;
-  bool Get(const std::string& key, bool* value, bool defaultValue = false) const;
-  bool Get(const std::string& key, float* value, float defaultValue = 0.0f) const;
-  bool Get(const std::string& key, double* value, double defaultValue = 0.0) const;
-
-  template <typename T>
-  T Get(const std::string& key, const T& default_value) const
-  {
-    T value;
-    Get(key, &value, default_value);
-    return value;
-  }
-
-  // Section chunk
-  void SetLines(const std::vector<std::string>& lines);
-  // XXX: Add to recursive layer
-  virtual bool GetLines(std::vector<std::string>* lines, const bool remove_comments = true) const;
-  virtual bool HasLines() const;
-  const std::string& GetName() const;
-  const SectionValueMap& GetValues() const;
-  const std::vector<std::string>& GetDeletedKeys() const;
-  bool IsDirty() const;
-  void ClearDirty();
-
-protected:
-  bool m_dirty = false;
-
-  LayerType m_layer;
-  System m_system;
-  const std::string m_name;
-  static const std::string& NULL_STRING;
-
-  SectionValueMap m_values;
-  std::vector<std::string> m_deleted_keys;
-
-  std::vector<std::string> m_lines;
-};
-}