From 757710797e03d45766ce0309e69aff6627f90e31 Mon Sep 17 00:00:00 2001
From: Mathew Sutcliffe <oktal3700@gmail.com>
Date: Sun, 20 Dec 2015 22:08:49 +0000
Subject: [PATCH] refs #545 Refactoring: extract method elementsStartingWith.

---
 src/blackmisc/valuecache.cpp |  4 ++--
 src/blackmisc/valuecache.h   | 17 +++++++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/blackmisc/valuecache.cpp b/src/blackmisc/valuecache.cpp
index 030335924..b73408528 100644
--- a/src/blackmisc/valuecache.cpp
+++ b/src/blackmisc/valuecache.cpp
@@ -117,7 +117,7 @@ namespace BlackMisc
     {
         QMutexLocker lock(&m_mutex);
         CVariantMap map;
-        for (const auto &element : makeRange(m_elements.lowerBound(keyPrefix), m_elements.lowerBound(keyPrefix + QChar(QChar::LastValidCodePoint))))
+        for (const auto &element : elementsStartingWith(keyPrefix))
         {
             implementationOf(map).insert(map.cend(), element->m_key, element->m_value);
         }
@@ -128,7 +128,7 @@ namespace BlackMisc
     {
         QMutexLocker lock(&m_mutex);
         CValueCachePacket map;
-        for (const auto &element : makeRange(m_elements.lowerBound(keyPrefix), m_elements.lowerBound(keyPrefix + QChar(QChar::LastValidCodePoint))))
+        for (const auto &element : elementsStartingWith(keyPrefix))
         {
             map.insert(element->m_key, element->m_value, element->m_timestamp);
         }
diff --git a/src/blackmisc/valuecache.h b/src/blackmisc/valuecache.h
index 109216cf2..de345fca8 100644
--- a/src/blackmisc/valuecache.h
+++ b/src/blackmisc/valuecache.h
@@ -13,6 +13,7 @@
 #define BLACKMISC_VALUECACHE_H
 
 #include "blackmisc/valuecacheprivate.h"
+#include "blackmisc/range.h"
 
 namespace BlackMisc
 {
@@ -160,7 +161,23 @@ namespace BlackMisc
         //! of CValueCache instances in all processes including this one. The slot will do its own round-trip detection.
         void valuesChangedByLocal(const BlackMisc::CValueCachePacket &values);
 
+    private:
+        struct Element; // remove forward declaration when elementsStartingWith uses C++14 auto deduced return type
+
     protected:
+        //! Returns a range referring to all elements which start with the given prefix.
+        //! \todo Use C++14 auto deduced return type.
+        //! @{
+        auto elementsStartingWith(const QString &keyPrefix) -> CRange<QMap<QString, QSharedPointer<Element>>::iterator>
+        {
+            return makeRange(m_elements.lowerBound(keyPrefix), m_elements.lowerBound(keyPrefix + QChar(QChar::LastValidCodePoint)));
+        }
+        auto elementsStartingWith(const QString &keyPrefix) const -> CRange<QMap<QString, QSharedPointer<Element>>::const_iterator>
+        {
+            return makeRange(m_elements.lowerBound(keyPrefix), m_elements.lowerBound(keyPrefix + QChar(QChar::LastValidCodePoint)));
+        }
+        //! @}
+
         //! Save specific values to Json files in a given directory.
         //! \threadsafe
         CStatusMessage saveToFiles(const QString &directory, const CVariantMap &values) const;