[calculation] Do not memoize the expression layouts but the expressions

final height to avoid overflowing the heap. The expression layouts are
kept in the cell which are fewer then the number of calculations

apps/calculation/calculation.cpp

@@ -11,20 +11,14 @@ Calculation::Calculation() :
   m_exactOutputText(),
   m_approximateOutputText(),
   m_input(nullptr),
-  m_inputLayout(nullptr),
   m_exactOutput(nullptr),
-  m_exactOutputLayout(nullptr),
   m_approximateOutput(nullptr),
-  m_approximateOutputLayout(nullptr),
+  m_height(-1),
   m_equalSign(EqualSign::Unknown)
 {
 }
 
 Calculation::~Calculation() {
-  if (m_inputLayout != nullptr) {
-    delete m_inputLayout;
-    m_inputLayout = nullptr;
-  }
   if (m_input != nullptr) {
     delete m_input;
     m_input = nullptr;
@@ -33,18 +27,10 @@ Calculation::~Calculation() {
     delete m_exactOutput;
     m_exactOutput = nullptr;
   }
-  if (m_exactOutputLayout != nullptr) {
-    delete m_exactOutputLayout;
-    m_exactOutputLayout = nullptr;
-  }
   if (m_approximateOutput != nullptr) {
     delete m_approximateOutput;
     m_approximateOutput = nullptr;
   }
-  if (m_approximateOutputLayout != nullptr) {
-    delete m_approximateOutputLayout;
-    m_approximateOutputLayout = nullptr;
-  }
 }
 
 Calculation& Calculation::operator=(const Calculation& other) {
@@ -78,6 +64,27 @@ void Calculation::setContent(const char * c, Context * context, Expression * ans
   m_approximateOutput->writeTextInBuffer(m_approximateOutputText, sizeof(m_approximateOutputText));
 }
 
+KDCoordinate Calculation::height(Context * context) {
+  if (m_height < 0) {
+    ExpressionLayout * inputLayout = createInputLayout();
+    KDCoordinate inputHeight = inputLayout->size().height();
+    delete inputLayout;
+    Poincare::ExpressionLayout * approximateLayout = createApproximateOutputLayout(context);
+    KDCoordinate approximateOutputHeight = approximateLayout->size().height();
+    if (shouldOnlyDisplayApproximateOutput(context)) {
+      m_height = inputHeight+approximateOutputHeight;
+    } else {
+      Poincare::ExpressionLayout * exactLayout = createExactOutputLayout(context);
+      KDCoordinate exactOutputHeight = exactLayout->size().height();
+      KDCoordinate outputHeight = max(exactLayout->baseline(), approximateLayout->baseline()) + max(exactOutputHeight-exactLayout->baseline(), approximateOutputHeight-approximateLayout->baseline());
+      delete exactLayout;
+      m_height = inputHeight + outputHeight;
+    }
+    delete approximateLayout;
+  }
+  return m_height;
+}
+
 const char * Calculation::inputText() {
   return m_inputText;
 }
@@ -97,11 +104,11 @@ Expression * Calculation::input() {
   return m_input;
 }
 
-ExpressionLayout * Calculation::inputLayout() {
-  if (m_inputLayout == nullptr && input() != nullptr) {
-    m_inputLayout = input()->createLayout(PrintFloat::Mode::Decimal, Expression::ComplexFormat::Cartesian);
+ExpressionLayout * Calculation::createInputLayout() {
+  if (input() != nullptr) {
+    return input()->createLayout(PrintFloat::Mode::Decimal, Expression::ComplexFormat::Cartesian);
   }
-  return m_inputLayout;
+  return nullptr;
 }
 
 bool Calculation::isEmpty() {
@@ -123,26 +130,15 @@ void Calculation::tidy() {
     delete m_input;
   }
   m_input = nullptr;
-  if (m_inputLayout != nullptr) {
-    delete m_inputLayout;
-  }
-  m_inputLayout = nullptr;
   if (m_exactOutput != nullptr) {
     delete m_exactOutput;
   }
   m_exactOutput = nullptr;
-  if (m_exactOutputLayout != nullptr) {
-    delete m_exactOutputLayout;
-  }
-  m_exactOutputLayout = nullptr;
   if (m_approximateOutput != nullptr) {
     delete m_approximateOutput;
   }
   m_approximateOutput = nullptr;
-  if (m_approximateOutputLayout != nullptr) {
-    delete m_approximateOutputLayout;
-  }
-  m_approximateOutputLayout = nullptr;
+  m_height = -1;
   m_equalSign = EqualSign::Unknown;
 }
 
@@ -155,11 +151,11 @@ Expression * Calculation::exactOutput(Context * context) {
   return m_exactOutput;
 }
 
-ExpressionLayout * Calculation::exactOutputLayout(Context * context) {
-  if (m_exactOutputLayout == nullptr && exactOutput(context) != nullptr) {
-    m_exactOutputLayout = exactOutput(context)->createLayout();
+ExpressionLayout * Calculation::createExactOutputLayout(Context * context) {
+  if (exactOutput(context) != nullptr) {
+    return exactOutput(context)->createLayout();
   }
-  return m_exactOutputLayout;
+  return nullptr;
 }
 
 Expression * Calculation::approximateOutput(Context * context) {
@@ -177,11 +173,11 @@ Expression * Calculation::approximateOutput(Context * context) {
   return m_approximateOutput;
 }
 
-ExpressionLayout * Calculation::approximateOutputLayout(Context * context) {
-  if (m_approximateOutputLayout == nullptr && approximateOutput(context) != nullptr) {
-    m_approximateOutputLayout = approximateOutput(context)->createLayout();
+ExpressionLayout * Calculation::createApproximateOutputLayout(Context * context) {
+  if (approximateOutput(context) != nullptr) {
+    return approximateOutput(context)->createLayout();
   }
-  return m_approximateOutputLayout;
+  return nullptr;
 }
 
 bool Calculation::shouldOnlyDisplayApproximateOutput(Context * context) {