[apps/calc] Handle alloc failure when computing calculation height

apps/calculation/calculation.cpp

@@ -70,6 +70,12 @@ void Calculation::setContent(const char * c, Context * context, Expression * ans
 KDCoordinate Calculation::height(Context * context) {
   if (m_height < 0) {
     LayoutRef inputLayout = createInputLayout();
+    if (inputLayout.isAllocationFailure()) {
+      /* If there is not enough tree pool space to create the layout, return a
+       * default height. Do not store it in m_height in case some memory get
+       * freed afterwards. */
+      return k_heightComputationFailureHeight;
+    }
     KDCoordinate inputHeight = inputLayout.layoutSize().height();
     LayoutRef approximateLayout = createApproximateOutputLayout(context);
     KDCoordinate approximateOutputHeight = approximateLayout.layoutSize().height();

apps/calculation/calculation.h

@@ -40,6 +40,7 @@ public:
   EqualSign exactAndApproximateDisplayedOutputsAreEqual(Poincare::Context * context);
   constexpr static int k_printedExpressionSize = 2*::TextField::maxBufferSize();
 private:
+  static constexpr KDCoordinate k_heightComputationFailureHeight = 50;
   /* Buffers holding text expressions have to be longer than the text written
    * by user (of maximum length TextField::maxBufferSize()) because when we
    * print an expression we add omitted signs (multiplications, parenthesis...) */