Make the QMultiHash(const QHash &) constructor explicit

And add a QMultiHash::unite(const QHash &) method to avoid
a copy of the data when inserting a QHash into a multi hash.

Change-Id: I864aa9d2b9b7b2c367c3c4d140a2ce2f5408ae09
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index 67b3e026df..1f0d5d76ad 100644
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -1219,7 +1219,7 @@ public:
         return *this;
     }
 
-    QMultiHash(const QHash<Key, T> &other)
+    explicit QMultiHash(const QHash<Key, T> &other)
         : QMultiHash(other.begin(), other.end())
     {}
     void swap(QMultiHash &other) noexcept { qSwap(d, other.d); qSwap(m_size, other.m_size); }
@@ -1808,6 +1808,13 @@ public:
         return *this;
     }
 
+    QMultiHash &unite(const QHash<Key, T> &other)
+    {
+        for (auto cit = other.cbegin(); cit != other.cend(); ++cit)
+            insert(cit.key(), *cit);
+        return *this;
+    }
+
     QPair<iterator, iterator> equal_range(const Key &key)
     {
         detach();