[apps/graph_ctrlr] Reload range if no previous model is present

We memoize the checksum of the x first models, and we check that one of
these models is still present when the graph view appears. If so, we do
not reload the range, other wise we reload it.

Scenario:
f(t) = [t^2  t+1] in parametric
Display the graph
f(x) = 1 on ]-inf;0]
g(x) = 2 on [0;inf[
Display the graph -> the range did not change

apps/regression/app.cpp

@@ -37,7 +37,8 @@ App * App::Snapshot::unpack(Container * container) {
 void App::Snapshot::reset() {
   m_store.deleteAllPairs();
   m_modelVersion = 0;
-  memset(m_previousModelsVersions, 0, sizeof(m_previousModelsVersions[0])*sNumberOfMemoizedModelVersions);
+  assert(sizeof(m_previousModelsVersions) == sizeof(uint32_t) * GraphController::sNumberOfMemoizedModelVersions);
+  memset(m_previousModelsVersions, 0, sizeof(m_previousModelsVersions));
   m_rangeVersion = 0;
   setActiveTab(0);
 }

apps/regression/app.h

@@ -21,7 +21,6 @@ public:
   };
   class Snapshot : public ::App::Snapshot, public TabViewDataSource {
   public:
-    static constexpr size_t sNumberOfMemoizedModelVersions = 5; // TODO LEA factorize with Shared::FunctionApp
     Snapshot();
     App * unpack(Container * container) override;
     void reset() override;
@@ -39,7 +38,7 @@ public:
     Shared::CurveViewCursor m_cursor;
     int m_graphSelectedDotIndex;
     uint32_t m_modelVersion;
-    uint32_t m_previousModelsVersions[sNumberOfMemoizedModelVersions];
+    uint32_t m_previousModelsVersions[GraphController::sNumberOfMemoizedModelVersions];
     uint32_t m_rangeVersion;
     int m_selectedSeriesIndex;
   };

apps/regression/graph_controller.cpp

@@ -351,6 +351,10 @@ uint32_t GraphController::modelVersion() {
   return m_store->storeChecksum();
 }
 
+uint32_t GraphController::modelVersionAtIndex(size_t i) {
+  return m_store->seriesChecksumAtIndex(i);
+}
+
 uint32_t GraphController::rangeVersion() {
   return m_store->rangeChecksum();
 }

apps/regression/graph_controller.h

@@ -16,6 +16,7 @@ namespace Regression {
 class GraphController : public Shared::InteractiveCurveViewController {
 
 public:
+  static constexpr size_t sNumberOfMemoizedModelVersions = Store::k_numberOfSeries;
   GraphController(Responder * parentResponder, InputEventHandlerDelegate * inputEventHandlerDelegate, ButtonRowController * header, Store * store, Shared::CurveViewCursor * cursor, uint32_t * modelVersion, uint32_t * previousModelsVersions, uint32_t * rangeVersion, int * selectedDotIndex, int * selectedSeriesIndex);
   ViewController * initialisationParameterController() override;
   bool isEmpty() const override;
@@ -43,7 +44,9 @@ private:
   // InteractiveCurveViewController
   void initCursorParameters() override;
   uint32_t modelVersion() override;
+  uint32_t modelVersionAtIndex(size_t i) override;
   uint32_t rangeVersion() override;
+  size_t numberOfMemoizedVersions() const override { return sNumberOfMemoizedModelVersions; }
   int selectedCurveIndex() const override { return *m_selectedSeriesIndex; }
   bool closestCurveIndexIsSuitable(int newIndex, int currentIndex) const override;
   Poincare::Coordinate2D<double> xyValues(int curveIndex, double x, Poincare::Context * context) const override;

apps/regression/store.h

@@ -35,6 +35,10 @@ public:
     assert((int)m_regressionTypes[series] >= 0 && (int)m_regressionTypes[series] < Model::k_numberOfModels);
     return regressionModel((int)m_regressionTypes[series]);
   }
+  uint32_t seriesChecksumAtIndex(size_t i) {
+    assert(i < k_numberOfSeries);
+    return m_seriesChecksum[i];
+  }
 
   // Dots
   /* Return the closest dot to abscissa x above the regression curve if

apps/shared/function_app.cpp

@@ -17,7 +17,8 @@ FunctionApp::Snapshot::Snapshot() :
 void FunctionApp::Snapshot::reset() {
   m_indexFunctionSelectedByCursor = 0;
   m_modelVersion = 0;
-  memset(m_previousModelsVersions, 0, sizeof(m_previousModelsVersions[0])*sNumberOfMemoizedModelVersions);
+  assert(sizeof(m_previousModelsVersions) == sizeof(uint32_t) * FunctionGraphController::sNumberOfMemoizedModelVersions);
+  memset(m_previousModelsVersions, 0, sizeof(m_previousModelsVersions));
   m_rangeVersion = 0;
   setActiveTab(0);
 }

apps/shared/function_app.h

@@ -2,6 +2,7 @@
 #define SHARED_FUNCTION_APP_H
 
 #include "expression_field_delegate_app.h"
+#include "function_graph_controller.h"
 #include "function_store.h"
 #include "curve_view_cursor.h"
 #include "values_controller.h"
@@ -12,7 +13,6 @@ class FunctionApp : public ExpressionFieldDelegateApp {
 public:
   class Snapshot : public ::App::Snapshot, public TabViewDataSource {
   public:
-    static constexpr size_t sNumberOfMemoizedModelVersions = 5;
     Snapshot();
     CurveViewCursor * cursor() { return &m_cursor; }
     uint32_t * modelVersion() { return &m_modelVersion; }
@@ -28,7 +28,7 @@ public:
   private:
     int m_indexFunctionSelectedByCursor;
     uint32_t m_modelVersion;
-    uint32_t m_previousModelsVersions[sNumberOfMemoizedModelVersions];
+    uint32_t m_previousModelsVersions[FunctionGraphController::sNumberOfMemoizedModelVersions];
     uint32_t m_rangeVersion;
     Poincare::Preferences::AngleUnit m_angleUnitVersion;
   };

apps/shared/function_graph_controller.cpp

@@ -183,6 +183,10 @@ uint32_t FunctionGraphController::modelVersion() {
   return functionStore()->storeChecksum();
 }
 
+uint32_t FunctionGraphController::modelVersionAtIndex(size_t i) {
+  return functionStore()->storeChecksumAtIndex(i);
+}
+
 uint32_t FunctionGraphController::rangeVersion() {
   return interactiveCurveViewRange()->rangeChecksum();
 }

apps/shared/function_graph_controller.h

@@ -13,6 +13,7 @@ namespace Shared {
 
 class FunctionGraphController : public InteractiveCurveViewController, public FunctionBannerDelegate {
 public:
+  static constexpr size_t sNumberOfMemoizedModelVersions = 5;
   FunctionGraphController(Responder * parentResponder, InputEventHandlerDelegate * inputEventHandlerDelegate, ButtonRowController * header,  InteractiveCurveViewRange * interactiveRange, CurveView * curveView, CurveViewCursor * cursor, int * indexFunctionSelectedByCursor, uint32_t * modelVersion, uint32_t * previousModelsVersions, uint32_t * rangeVersion, Poincare::Preferences::AngleUnit * angleUnitVersion);
   bool isEmpty() const override;
   ViewController * initialisationParameterController() override;
@@ -49,7 +50,9 @@ private:
   // InteractiveCurveViewController
   bool moveCursorVertically(int direction) override;
   uint32_t modelVersion() override;
+  uint32_t modelVersionAtIndex(size_t i) override;
   uint32_t rangeVersion() override;
+  size_t numberOfMemoizedVersions() const override { return sNumberOfMemoizedModelVersions; }
 
   InitialisationParameterController m_initialisationParameterController;
   Poincare::Preferences::AngleUnit * m_angleUnitVersion;

apps/shared/function_store.cpp

@@ -6,4 +6,11 @@ uint32_t FunctionStore::storeChecksum() {
   return Ion::Storage::sharedStorage()->checksum();
 }
 
+uint32_t FunctionStore::storeChecksumAtIndex(size_t i) {
+  if (numberOfActiveFunctions() <= i) {
+    return 0;
+  }
+  return activeRecordAtIndex(i).checksum();
+}
+
 }

apps/shared/function_store.h

@@ -13,6 +13,7 @@ class FunctionStore : public ExpressionModelStore {
 public:
   FunctionStore() : ExpressionModelStore() {}
   uint32_t storeChecksum();
+  uint32_t storeChecksumAtIndex(size_t i);
   int numberOfActiveFunctions() const {
     return numberOfModelsSatisfyingTest(&isFunctionActive, nullptr);
   }

apps/shared/interactive_curve_view_controller.cpp

@@ -133,11 +133,43 @@ Responder * InteractiveCurveViewController::defaultController() {
   return tabController();
 }
 
+bool InteractiveCurveViewController::previousModelsWereAllDeleted() {
+  bool result = true;
+  const int modelsCount = numberOfCurves();
+  const int memoizationCount = numberOfMemoizedVersions();
+
+  // Look for a current model that is the same as in the previous version
+  for (int i = 0; i < modelsCount; i++) {
+    uint32_t currentVersion = modelVersionAtIndex(i);
+    for (int j = 0; j < memoizationCount; j++) {
+      uint32_t * previousVersion = m_previousModelsVersions + j;
+      if (currentVersion == *previousVersion) {
+        result = false;
+        break;
+      }
+    }
+    if (!result) {
+      break;
+    }
+  }
+
+  // Update the memoization
+  for (int i = 0; i < memoizationCount; i++) {
+    uint32_t * previousVersion = m_previousModelsVersions + i;
+    uint32_t newVersion = modelVersionAtIndex(i);
+    if (*previousVersion != newVersion) {
+      *previousVersion = newVersion;
+    }
+  }
+  return result;
+}
+
 void InteractiveCurveViewController::viewWillAppear() {
   SimpleInteractiveCurveViewController::viewWillAppear();
   uint32_t newModelVersion = modelVersion();
   if (*m_modelVersion != newModelVersion) {
-    if (*m_modelVersion == 0 || numberOfCurves() == 1 || shouldSetDefaultOnModelChange()) {
+    // Put previousModelsWereAllDeleted first to update the model versions
+    if (previousModelsWereAllDeleted() || *m_modelVersion == 0 || numberOfCurves() == 1 || shouldSetDefaultOnModelChange()) {
       interactiveCurveViewRange()->setDefault();
     }
     *m_modelVersion = newModelVersion;

apps/shared/interactive_curve_view_controller.h

@@ -28,6 +28,8 @@ public:
 
   Responder * defaultController() override;
 
+  bool previousModelsWereAllDeleted();
+
   void viewWillAppear() override;
   void viewDidDisappear() override;
   void willExitResponderChain(Responder * nextFirstResponder) override;
@@ -39,6 +41,7 @@ protected:
   virtual void initCursorParameters() = 0;
   virtual bool moveCursorVertically(int direction) = 0;
   virtual uint32_t modelVersion() = 0;
+  virtual uint32_t modelVersionAtIndex(size_t i) = 0;
   virtual uint32_t rangeVersion() = 0;
   bool isCursorVisible();
 
@@ -66,6 +69,7 @@ private:
   float addMargin(float x, float range, bool isVertical, bool isMin) override;
 
   virtual bool shouldSetDefaultOnModelChange() const { return false; }
+  virtual size_t numberOfMemoizedVersions() const = 0;
   uint32_t * m_modelVersion;
   uint32_t * m_previousModelsVersions;
   uint32_t * m_rangeVersion;