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QGraphicsView: Graph: don't allocate QHashes on the heap 

... just so you can observe their absence with QHash::value()
returning nullptr.

Instead, use find() + comparison to end() to detect presence
or absence.

Simplifies quite a bit of code.

Change-Id: Ifd7921bfc8102677ea345ae37d38da31b8105426
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>
bb10
Marc Mutz 2016-01-16 20:24:03 +01:00
parent a0cee9916a
commit d569f37dfd
1 changed files with 23 additions and 26 deletions
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49
src/widgets/graphicsview/qgraph_p.h
View File

@ -75,9 +75,7 @@ public:
row = g->m_graph.constBegin();
//test if the graph is empty
if (row != g->m_graph.constEnd())
{
column = (*row)->constBegin();
}
column = row->cbegin();
} else {
row = g->m_graph.constEnd();
}
@ -108,10 +106,10 @@ public:
const_iterator &operator++() {
if (row != g->m_graph.constEnd()) {
++column;
if (column == (*row)->constEnd()) {
if (column == row->cend()) {
++row;
if (row != g->m_graph.constEnd()) {
column = (*row)->constBegin();
column = row->cbegin();
}
}
}
@ -120,7 +118,7 @@ public:
private:
const Graph *g;
typename QHash<Vertex *, QHash<Vertex *, EdgeData *> * >::const_iterator row;
typename QHash<Vertex *, QHash<Vertex *, EdgeData *> >::const_iterator row;
typename QHash<Vertex *, EdgeData *>::const_iterator column;
};
@ -140,8 +138,13 @@ public:
*
*/
EdgeData *edgeData(Vertex* first, Vertex* second) {
QHash<Vertex *, EdgeData *> *row = m_graph.value(first);
return row ? row->value(second) : 0;
const auto it = m_graph.constFind(first);
if (it == m_graph.cend())
return nullptr;
const auto jt = it->constFind(second);
if (jt == it->cend())
return nullptr;
return *jt;
}
void createEdge(Vertex *first, Vertex *second, EdgeData *data)
@ -193,11 +196,11 @@ public:
QList<Vertex *> adjacentVertices(Vertex *vertex) const
{
QHash<Vertex *, EdgeData *> *row = m_graph.value(vertex);
QList<Vertex *> l;
if (row)
l = row->keys();
return l;
const auto it = m_graph.constFind(vertex);
if (it == m_graph.cend())
return QList<Vertex *>();
else
return it->keys();
}
QSet<Vertex*> vertices() const {
@ -253,29 +256,23 @@ public:
protected:
void createDirectedEdge(Vertex *from, Vertex *to, EdgeData *data)
{
QHash<Vertex *, EdgeData *> *adjacentToFirst = m_graph.value(from);
if (!adjacentToFirst) {
adjacentToFirst = new QHash<Vertex *, EdgeData *>();
m_graph.insert(from, adjacentToFirst);
}
adjacentToFirst->insert(to, data);
m_graph[from][to] = data;
}
void removeDirectedEdge(Vertex *from, Vertex *to)
{
QHash<Vertex *, EdgeData *> *adjacentToFirst = m_graph.value(from);
Q_ASSERT(adjacentToFirst);
const auto it = m_graph.find(from);
Q_ASSERT(it != m_graph.end());
adjacentToFirst->remove(to);
if (adjacentToFirst->isEmpty()) {
it->remove(to);
if (it->isEmpty()) {
//nobody point to 'from' so we can remove it from the graph
m_graph.remove(from);
delete adjacentToFirst;
m_graph.erase(it);
}
}
private:
QHash<Vertex *, QHash<Vertex *, EdgeData *> *> m_graph;
QHash<Vertex *, QHash<Vertex *, EdgeData *> > m_graph;
};
QT_END_NAMESPACE