make NodeSet implicitly shared

This enables us to use the foreach macro without deep-copying the
container.

Change-Id: I6eb5ff5874a5065ff4b89e6cbde2b78c6fb0a950
Task-number: QBS-778
Reviewed-by: Christian Kandeler <christian.kandeler@theqtcompany.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/src/lib/corelib/buildgraph/nodeset.cpp b/src/lib/corelib/buildgraph/nodeset.cpp
index c24af87d8..61cbbc9df 100644
--- a/src/lib/corelib/buildgraph/nodeset.cpp
+++ b/src/lib/corelib/buildgraph/nodeset.cpp
@@ -40,23 +40,19 @@ namespace qbs {
 namespace Internal {
 
 NodeSet::NodeSet()
-{
-}
-
-NodeSet::NodeSet(const NodeSet &other)
-    : m_data(other.m_data)
+    : d(new NodeSetData)
 {
 }
 
 NodeSet &NodeSet::unite(const NodeSet &other)
 {
-    m_data.insert(other.begin(), other.end());
+    d->m_data.insert(other.begin(), other.end());
     return *this;
 }
 
 void NodeSet::remove(BuildGraphNode *node)
 {
-    m_data.erase(node);
+    d->m_data.erase(node);
 }
 
 void NodeSet::load(PersistentPool &pool)