fix: add a wrapper for std::valarray to catch out of range access

If we have a recording with the following layout: A B C where A: part
where function f is accessed
B: list samples
C: part where function g is accessed
then f won't have the lost events cost while g does. This will cause a
crash when the model tries to access it.

This patch replaces the typedef ItemCost with a real wrapper that will
catch the out range access.

fixes: #629

src/models/data.cpp

@@ -12,6 +12,79 @@
 
 using namespace Data;
 
+ItemCost::ItemCost(std::size_t size)
+    : m_cost(size)
+{
+}
+
+ItemCost::ItemCost(qint64 value, std::size_t count)
+    : m_cost(value, count)
+{
+}
+
+ItemCost::ItemCost(std::valarray<qint64>&& cost)
+    : m_cost(cost)
+{
+}
+ItemCost::~ItemCost() = default;
+
+void ItemCost::resize(std::size_t newSize, qint64 value)
+{
+    m_cost.resize(newSize, value);
+}
+
+std::size_t ItemCost::size() const
+{
+    return m_cost.size();
+}
+
+ItemCost ItemCost::operator+(const ItemCost& rhs) const
+{
+    return static_cast<std::valarray<qint64>>(m_cost + rhs.m_cost);
+}
+
+ItemCost ItemCost::operator-(const ItemCost& rhs) const
+{
+    return static_cast<std::valarray<qint64>>(m_cost - rhs.m_cost);
+}
+
+ItemCost& ItemCost::operator+=(const ItemCost& rhs)
+{
+    m_cost += rhs.m_cost;
+    return *this;
+}
+
+qint64& ItemCost::operator[](int index)
+{
+    if (static_cast<std::size_t>(index) >= m_cost.size()) {
+        resize(index + 1);
+    }
+    return m_cost[index];
+}
+
+qint64 ItemCost::operator[](int index) const
+{
+    if (static_cast<std::size_t>(index) < m_cost.size()) {
+        return m_cost[index];
+    }
+    return 0;
+}
+
+qint64 ItemCost::sum() const
+{
+    return m_cost.sum();
+}
+
+auto ItemCost::begin() const
+{
+    return std::begin(m_cost);
+}
+
+auto ItemCost::end() const
+{
+    return std::end(m_cost);
+}
+
 namespace {
 
 ItemCost buildTopDownResult(const BottomUp& bottomUpData, const Costs& bottomUpCosts, TopDown* topDownData,

src/models/data.h

@@ -203,7 +203,32 @@ struct FrameLocation
     Data::Location location;
 };
 
-using ItemCost = std::valarray<qint64>;
+class ItemCost
+{
+public:
+    ItemCost(std::size_t size = 0);
+    ItemCost(qint64 value, std::size_t count);
+    ItemCost(std::valarray<qint64>&& cost);
+    ~ItemCost();
+
+    void resize(std::size_t newSize, qint64 value = 0);
+    std::size_t size() const;
+
+    ItemCost operator+(const ItemCost& rhs) const;
+    ItemCost operator-(const ItemCost& rhs) const;
+    ItemCost& operator+=(const ItemCost& rhs);
+
+    qint64& operator[](int index);
+    qint64 operator[](int index) const;
+
+    qint64 sum() const;
+
+    auto begin() const;
+    auto end() const;
+
+private:
+    std::valarray<qint64> m_cost;
+};
 
 QDebug operator<<(QDebug stream, const ItemCost& cost);
 

src/recordpage.cpp

@@ -40,6 +40,8 @@
 #include <Solid/Device>
 #include <Solid/Processor>
 
+#include <cmath>
+
 #include "multiconfigwidget.h"
 #include "perfoutputwidgetkonsole.h"
 #include "perfoutputwidgettext.h"

src/util.h

@@ -7,7 +7,6 @@
 
 #pragma once
 
-#include <valarray>
 #include <QHashFunctions>
 #include <QtGlobal>
 
@@ -20,7 +19,7 @@ struct Symbol;
 struct FileLine;
 struct LocationCost;
 class Costs;
-using ItemCost = std::valarray<qint64>;
+class ItemCost;
 }
 
 namespace KParts {