Non-associative containers: add range constructors

Something nice we'd like to detect for array-backed containers
is if the iterator passed is a Contiguous one; if the type is also
trivially copyable / Q_PRIMITIVE_TYPE, we could memcpy() the whole
range.

However, there's no trait in the Standard to detect contiguous
iterators (the best approximation would be detecting if the iterator
is actually a pointer). Also, it's probably not smart to do the work
now for QVector since QVector needs refactoring anyhow, and this work
will be lost.

QString and QByteArray are left in another commit.

[ChangeLog][QtCore][QVector] Added range constructor.

[ChangeLog][QtCore][QVarLengthArray] Added range constructor.

[ChangeLog][QtCore][QList] Added range constructor.

[ChangeLog][QtCore][QStringList] Added range constructor.

[ChangeLog][QtCore][QLinkedList] Added range constructor.

[ChangeLog][QtCore][QSet] Added range constructor.

Change-Id: I220edb796053c9c4d31a6dbdc7efc5fc0f6678f9
Reviewed-by: Milian Wolff <milian.wolff@kdab.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/src/corelib/tools/qlinkedlist.h b/src/corelib/tools/qlinkedlist.h
index 91367a74b3..83f70deceb 100644
--- a/src/corelib/tools/qlinkedlist.h
+++ b/src/corelib/tools/qlinkedlist.h
@@ -42,6 +42,7 @@
 
 #include <QtCore/qiterator.h>
 #include <QtCore/qrefcount.h>
+#include <QtCore/qcontainertools_impl.h>
 
 #include <iterator>
 #include <list>
@@ -84,11 +85,14 @@ public:
     inline QLinkedList(const QLinkedList<T> &l) : d(l.d) { d->ref.ref(); if (!d->sharable) detach(); }
 #if defined(Q_COMPILER_INITIALIZER_LISTS)
     inline QLinkedList(std::initializer_list<T> list)
-        : d(const_cast<QLinkedListData *>(&QLinkedListData::shared_null))
+        : QLinkedList(list.begin(), list.end()) {}
+#endif
+    template <typename InputIterator, QtPrivate::IfIsInputIterator<InputIterator> = true>
+    inline QLinkedList(InputIterator first, InputIterator last)
+        : QLinkedList()
     {
-        std::copy(list.begin(), list.end(), std::back_inserter(*this));
+        std::copy(first, last, std::back_inserter(*this));
     }
-#endif
     ~QLinkedList();
     QLinkedList<T> &operator=(const QLinkedList<T> &);
 #ifdef Q_COMPILER_RVALUE_REFS