From 504223612dd7a1c6bd58c4241b8177fab32df2ee Mon Sep 17 00:00:00 2001
From: Gabriel Ozouf <gabriel.ozouf@numworks.com>
Date: Thu, 13 Aug 2020 13:22:39 +0200
Subject: [PATCH] [apps/apps_container] Add timer to circuit breaker

poincareCircuitBreaker requires the Back key to be pressed for at least
50 ms before interrupting a computation.
This is effectively invisible for the user, but fixes a bug in
Calculation :
  - When leaving the additional results for a result using units by
    pressing the Back key, a reduction preceding a call to removeUnits
    would be interrupted, causing an undefined behaviour.

Change-Id: Iec667ae964f190de2171850cc22e1726959e6cb5
---
 apps/apps_container.cpp          | 17 ++++++++++++++++-
 apps/calculation/calculation.cpp |  3 ---
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/apps/apps_container.cpp b/apps/apps_container.cpp
index a8cb20aa0..ca3c1be1c 100644
--- a/apps/apps_container.cpp
+++ b/apps/apps_container.cpp
@@ -51,8 +51,23 @@ AppsContainer::AppsContainer() :
 }
 
 bool AppsContainer::poincareCircuitBreaker() {
+  constexpr uint64_t minimalPressDuration = 20;
+  static uint64_t beginningOfInterruption = 0;
   Ion::Keyboard::State state = Ion::Keyboard::scan();
-  return state.keyDown(Ion::Keyboard::Key::Back) || state.keyDown(Ion::Keyboard::Key::Home) || state.keyDown(Ion::Keyboard::Key::OnOff);
+  bool interrupt = state.keyDown(Ion::Keyboard::Key::Back) || state.keyDown(Ion::Keyboard::Key::Home) || state.keyDown(Ion::Keyboard::Key::OnOff);
+  if (!interrupt) {
+    beginningOfInterruption = 0;
+    return false;
+  }
+  if (beginningOfInterruption == 0) {
+    beginningOfInterruption = Ion::Timing::millis();
+    return false;
+  }
+  if (Ion::Timing::millis() - beginningOfInterruption > minimalPressDuration) {
+    beginningOfInterruption = 0;
+    return true;
+  }
+  return false;
 }
 
 App::Snapshot * AppsContainer::hardwareTestAppSnapshot() {
diff --git a/apps/calculation/calculation.cpp b/apps/calculation/calculation.cpp
index 3c0372c8c..2ed67a817 100644
--- a/apps/calculation/calculation.cpp
+++ b/apps/calculation/calculation.cpp
@@ -254,9 +254,6 @@ Calculation::AdditionalInformationType Calculation::additionalInformationType(Co
   }
   if (o.hasUnit()) {
     Expression unit;
-    /* FIXME : When this method is accessed via leaving the additional outputs,
-     * ie via a press on BACK, the reduction is interrupted, and removeUnit
-     * goes badly.*/
     PoincareHelpers::Reduce(&o, App::app()->localContext(), ExpressionNode::ReductionTarget::User, ExpressionNode::SymbolicComputation::ReplaceAllSymbolsWithDefinitionsOrUndefined, ExpressionNode::UnitConversion::None);
     o = o.removeUnit(&unit);
     double value = PoincareHelpers::ApproximateToScalar<double>(o, App::app()->localContext());