From 1a9d736f28f176c27055d64881aae67883e4e28f Mon Sep 17 00:00:00 2001
From: mlangkabel <malte.langkabel@gmail.com>
Date: Thu, 21 Dec 2017 13:35:41 +0100
Subject: [PATCH] src: improved cache implementation

* use const ref in cache
* improved performance of FilePath caching in FileRegister
---
 src/lib/CMakeLists.txt                        |  3 +-
 src/lib/data/storage/PersistentStorage.cpp    |  5 ++-
 src/lib/utility/OrderedCache.h                | 45 +++++++++++++++++++
 src/lib/utility/{Cache.h => UnorderedCache.h} | 20 ++++-----
 src/lib/utility/file/FileRegister.cpp         |  6 +--
 src/lib/utility/file/FileRegister.h           |  4 +-
 src/lib_cxx/data/parser/cxx/CxxContext.h      |  6 +--
 7 files changed, 68 insertions(+), 21 deletions(-)
 create mode 100644 src/lib/utility/OrderedCache.h
 rename src/lib/utility/{Cache.h => UnorderedCache.h} (53%)

diff --git a/src/lib/CMakeLists.txt b/src/lib/CMakeLists.txt
index b5c89aa2..a2503cc2 100644
--- a/src/lib/CMakeLists.txt
+++ b/src/lib/CMakeLists.txt
@@ -510,9 +510,9 @@ add_files(
 	utility/ApplicationArchitectureType.h
 	utility/AppPath.cpp
 	utility/AppPath.h
-	utility/Cache.h
 	utility/ConfigManager.cpp
 	utility/ConfigManager.h
+	utility/OrderedCache.h
 	utility/OsType.h
 	utility/Property.h
 	utility/ResourcePaths.cpp
@@ -526,6 +526,7 @@ add_files(
 	utility/tracing.h
 	utility/Tree.h
 	utility/types.h
+	utility/UnorderedCache.h
 	utility/UserPaths.cpp
 	utility/UserPaths.h
 	utility/utility.cpp
diff --git a/src/lib/data/storage/PersistentStorage.cpp b/src/lib/data/storage/PersistentStorage.cpp
index 6791e8ed..372417c8 100644
--- a/src/lib/data/storage/PersistentStorage.cpp
+++ b/src/lib/data/storage/PersistentStorage.cpp
@@ -14,7 +14,7 @@
 #include "data/parser/ParseLocation.h"
 #include "data/NodeTypeSet.h"
 #include "settings/ApplicationSettings.h"
-#include "utility/Cache.h"
+#include "utility/UnorderedCache.h"
 #include "utility/file/FileInfo.h"
 #include "utility/file/FilePath.h"
 #include "utility/logging/logging.h"
@@ -1624,7 +1624,8 @@ std::vector<EdgeBookmark> PersistentStorage::getAllEdgeBookmarks() const
 
 	std::vector<EdgeBookmark> edgeBookmarks;
 
-	Cache<std::string, Id> nodeIdCache([&](std::string serializedNodeName)
+	UnorderedCache<std::string, Id> nodeIdCache(
+		[&](const std::string& serializedNodeName)
 		{
 			return m_sqliteIndexStorage.getNodeBySerializedName(serializedNodeName).id;
 		}
diff --git a/src/lib/utility/OrderedCache.h b/src/lib/utility/OrderedCache.h
new file mode 100644
index 00000000..f0ef24e5
--- /dev/null
+++ b/src/lib/utility/OrderedCache.h
@@ -0,0 +1,45 @@
+#ifndef ORDERED_CACHE_H
+#define ORDERED_CACHE_H
+
+#include <functional>
+#include <map>
+
+template <typename KeyType, typename ValType>
+class OrderedCache
+{
+public:
+	OrderedCache(std::function<ValType(const KeyType&)> calculator);
+	ValType getValue(const KeyType& key);
+
+private:
+	std::function<ValType(const KeyType&)> m_calculator;
+	std::map<KeyType, ValType> m_map;
+
+	size_t m_hitCount;
+	size_t m_missCount;
+};
+
+template <typename KeyType, typename ValType>
+OrderedCache<KeyType, ValType>::OrderedCache(std::function<ValType(const KeyType&)> calculator)
+	: m_calculator(calculator)
+	, m_hitCount(0)
+	, m_missCount(0)
+{
+}
+
+template <typename KeyType, typename ValType>
+ValType OrderedCache<KeyType, ValType>::getValue(const KeyType& key)
+{
+	typename std::map<KeyType, ValType>::const_iterator it = m_map.find(key);
+	if (it != m_map.end())
+	{
+		++m_hitCount;
+		return it->second;
+	}
+	++m_missCount;
+	ValType val = m_calculator(key);
+	m_map.insert(std::pair<KeyType, ValType>(key, val));
+	return val;
+}
+
+#endif // ORDERED_CACHE_H
diff --git a/src/lib/utility/Cache.h b/src/lib/utility/UnorderedCache.h
similarity index 53%
rename from src/lib/utility/Cache.h
rename to src/lib/utility/UnorderedCache.h
index 47ee4649..4ae043fa 100644
--- a/src/lib/utility/Cache.h
+++ b/src/lib/utility/UnorderedCache.h
@@ -1,18 +1,18 @@
-#ifndef CACHE_H
-#define CACHE_H
+#ifndef UNORDERED_CACHE_H
+#define UNORDERED_CACHE_H
 
 #include <functional>
 #include <unordered_map>
 
 template <typename KeyType, typename ValType, typename Hasher = std::hash<KeyType>>
-class Cache
+class UnorderedCache
 {
 public:
-	Cache(std::function<ValType(KeyType)> calculator);
-	ValType getValue(KeyType key);
+	UnorderedCache(std::function<ValType(const KeyType&)> calculator);
+	ValType getValue(const KeyType& key);
 
 private:
-	std::function<ValType(KeyType)> m_calculator;
+	std::function<ValType(const KeyType&)> m_calculator;
 	std::unordered_map<KeyType, ValType, Hasher> m_map;
 
 	size_t m_hitCount;
@@ -20,7 +20,7 @@ private:
 };
 
 template <typename KeyType, typename ValType, typename Hasher>
-Cache<KeyType, ValType, Hasher>::Cache(std::function<ValType(KeyType)> calculator)
+UnorderedCache<KeyType, ValType, Hasher>::UnorderedCache(std::function<ValType(const KeyType&)> calculator)
 	: m_calculator(calculator)
 	, m_hitCount(0)
 	, m_missCount(0)
@@ -28,9 +28,9 @@ Cache<KeyType, ValType, Hasher>::Cache(std::function<ValType(KeyType)> calculato
 }
 
 template <typename KeyType, typename ValType, typename Hasher>
-ValType Cache<KeyType, ValType, Hasher>::getValue(KeyType key)
+ValType UnorderedCache<KeyType, ValType, Hasher>::getValue(const KeyType& key)
 {
-	typename std::unordered_map<KeyType, ValType>::const_iterator it = m_map.find(key);
+	typename std::unordered_map<KeyType, ValType, Hasher>::const_iterator it = m_map.find(key);
 	if (it != m_map.end())
 	{
 		++m_hitCount;
@@ -42,4 +42,4 @@ ValType Cache<KeyType, ValType, Hasher>::getValue(KeyType key)
 	return val;
 }
 
-#endif // CACHE_H
+#endif // UNORDERED_CACHE_H
diff --git a/src/lib/utility/file/FileRegister.cpp b/src/lib/utility/file/FileRegister.cpp
index 7979579a..d7576b50 100644
--- a/src/lib/utility/file/FileRegister.cpp
+++ b/src/lib/utility/file/FileRegister.cpp
@@ -13,8 +13,8 @@ FileRegister::FileRegister(
 	, m_indexedPaths(indexedPaths)
 	, m_excludedPaths(excludedPaths)
 	, m_hasFilePathCache(
-		[&](std::string f){
-			const FilePath filePath(f);
+		[&](const FilePath& filePath)
+		{
 			bool ret = false;
 
 			if (filePath == m_currentPath)
@@ -100,5 +100,5 @@ bool FileRegister::fileIsIndexed(const FilePath& filePath) const
 
 bool FileRegister::hasFilePath(const FilePath& filePath) const
 {
-	return m_hasFilePathCache.getValue(filePath.str());
+	return m_hasFilePathCache.getValue(filePath);
 }
diff --git a/src/lib/utility/file/FileRegister.h b/src/lib/utility/file/FileRegister.h
index 13ce5548..febf111e 100644
--- a/src/lib/utility/file/FileRegister.h
+++ b/src/lib/utility/file/FileRegister.h
@@ -4,7 +4,7 @@
 #include <set>
 
 #include "utility/file/FileRegisterStateData.h"
-#include "utility/Cache.h"
+#include "utility/OrderedCache.h"
 
 class FileRegister
 {
@@ -29,7 +29,7 @@ private:
 	const FilePath& m_currentPath;
 	const std::set<FilePath> m_indexedPaths;
 	const std::set<FilePath> m_excludedPaths;
-	mutable Cache<std::string, bool> m_hasFilePathCache;
+	mutable OrderedCache<FilePath, bool> m_hasFilePathCache;
 };
 
 #endif // FILE_REGISTER_H
diff --git a/src/lib_cxx/data/parser/cxx/CxxContext.h b/src/lib_cxx/data/parser/cxx/CxxContext.h
index 6349f276..370705ad 100644
--- a/src/lib_cxx/data/parser/cxx/CxxContext.h
+++ b/src/lib_cxx/data/parser/cxx/CxxContext.h
@@ -4,10 +4,10 @@
 #include <clang/AST/Decl.h>
 
 #include "data/name/NameHierarchy.h"
-#include "utility/Cache.h"
+#include "utility/UnorderedCache.h"
 
-typedef Cache<const clang::NamedDecl*, NameHierarchy> DeclNameCache;
-typedef Cache<const clang::Type*, NameHierarchy> TypeNameCache;
+typedef UnorderedCache<const clang::NamedDecl*, NameHierarchy> DeclNameCache;
+typedef UnorderedCache<const clang::Type*, NameHierarchy> TypeNameCache;
 
 class CxxContext
 {