QFlatMap: optimize construction from existing containers

Use {copy,move} ctors instead of default-ctor, followed by
(move|copy)-assignment.

Pick-to: 6.3 6.2
Change-Id: Id2fd53050cd353a9374fd065ac25d753d42d1be9
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

1 files changed, 7 insertions, 14 deletions

diff --git a/src/corelib/tools/qflatmap_p.h b/src/corelib/tools/qflatmap_p.h
index 936b1749df..621eb7adba 100644
--- a/src/corelib/tools/qflatmap_p.h
+++ b/src/corelib/tools/qflatmap_p.h
@@ -439,23 +439,20 @@ public:
     }
 
     explicit QFlatMap(key_container_type &&keys, const mapped_container_type &values)
+        : c{std::move(keys), values}
     {
-        c.keys = std::move(keys);
-        c.values = values;
         ensureOrderedUnique();
     }
 
     explicit QFlatMap(const key_container_type &keys, mapped_container_type &&values)
+        : c{keys, std::move(values)}
     {
-        c.keys = keys;
-        c.values = std::move(values);
         ensureOrderedUnique();
     }
 
     explicit QFlatMap(key_container_type &&keys, mapped_container_type &&values)
+        : c{std::move(keys), std::move(values)}
     {
-        c.keys = std::move(keys);
-        c.values = std::move(values);
         ensureOrderedUnique();
     }
 
@@ -473,30 +470,26 @@ public:
 
     explicit QFlatMap(Qt::OrderedUniqueRange_t, const key_container_type &keys,
                       const mapped_container_type &values)
+        : c{keys, values}
     {
-        c.keys = keys;
-        c.values = values;
     }
 
     explicit QFlatMap(Qt::OrderedUniqueRange_t, key_container_type &&keys,
                       const mapped_container_type &values)
+        : c{std::move(keys), values}
     {
-        c.keys = std::move(keys);
-        c.values = values;
     }
 
     explicit QFlatMap(Qt::OrderedUniqueRange_t, const key_container_type &keys,
                       mapped_container_type &&values)
+        : c{keys, std::move(values)}
     {
-        c.keys = keys;
-        c.values = std::move(values);
     }
 
     explicit QFlatMap(Qt::OrderedUniqueRange_t, key_container_type &&keys,
                       mapped_container_type &&values)
+        : c{std::move(keys), std::move(values)}
     {
-        c.keys = std::move(keys);
-        c.values = std::move(values);
     }
 
     explicit QFlatMap(Qt::OrderedUniqueRange_t, std::initializer_list<value_type> lst)