From 6a1d38709339a471bd7d93715af499b8d1363b85 Mon Sep 17 00:00:00 2001
From: Paul Licameli <paul.licameli@audacityteam.org>
Date: Tue, 26 Apr 2016 15:37:55 -0400
Subject: [PATCH] Fix assertions and crashes in context menu for scrubber

---
 src/tracks/ui/Scrubbing.cpp | 24 ++++++++++++------------
 src/tracks/ui/Scrubbing.h   | 13 ++++++++++++-
 2 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/src/tracks/ui/Scrubbing.cpp b/src/tracks/ui/Scrubbing.cpp
index 036c4c1fc..3e158b04b 100644
--- a/src/tracks/ui/Scrubbing.cpp
+++ b/src/tracks/ui/Scrubbing.cpp
@@ -127,7 +127,7 @@ Scrubber::Scrubber(AudacityProject *project)
       wxTheApp->Connect
       (wxEVT_ACTIVATE_APP,
       wxActivateEventHandler(Scrubber::OnActivateOrDeactivateApp), NULL, this);
-   mProject->PushEventHandler(this);
+   mProject->PushEventHandler(&mForwarder);
 }
 
 Scrubber::~Scrubber()
@@ -455,32 +455,31 @@ void Scrubber::OnActivateOrDeactivateApp(wxActivateEvent &event)
    event.Skip();
 }
 
-void Scrubber::OnMouse(wxMouseEvent &event)
+void Scrubber::Forwarder::OnMouse(wxMouseEvent &event)
 {
-   auto isScrubbing = IsScrubbing();
-   if (!isScrubbing && HasStartedScrubbing()) {
+   auto isScrubbing = scrubber.IsScrubbing();
+   if (!isScrubbing && scrubber.HasStartedScrubbing()) {
       if (!event.HasAnyModifiers() &&
           event.GetEventType() == wxEVT_MOTION) {
 
          // Really start scrub if motion is far enough
-         auto ruler = mProject->GetRulerPanel();
+         auto ruler = scrubber.mProject->GetRulerPanel();
          auto xx = ruler->ScreenToClient(::wxGetMousePosition()).x;
-         MaybeStartScrubbing(xx
-                             );
+         scrubber.MaybeStartScrubbing(xx);
       }
    }
    else if (isScrubbing && !event.HasAnyModifiers()) {
       if(event.LeftDown() ||
          (event.LeftIsDown() && event.Dragging())) {
-         mScrubSeekPress = true;
-         auto ruler = mProject->GetRulerPanel();
+         scrubber.mScrubSeekPress = true;
+         auto ruler = scrubber.mProject->GetRulerPanel();
          auto xx = ruler->ScreenToClient(::wxGetMousePosition()).x;
          ruler->UpdateQuickPlayPos(xx);
       }
       else if (event.m_wheelRotation) {
          double steps = event.m_wheelRotation /
          (event.m_wheelDelta > 0 ? (double)event.m_wheelDelta : 120.0);
-         HandleScrollWheel(steps);
+         scrubber.HandleScrollWheel(steps);
       }
       else
          event.Skip();
@@ -700,9 +699,10 @@ BEGIN_EVENT_TABLE(Scrubber, wxEvtHandler)
    EVT_MENU(CMD_ID + 1, Scrubber::OnScrollScrub)
    EVT_MENU(CMD_ID + 2, Scrubber::OnSeek)
    EVT_MENU(CMD_ID + 3, Scrubber::OnScrollSeek)
+END_EVENT_TABLE()
 
-   EVT_MOUSE_EVENTS(Scrubber::OnMouse)
-
+BEGIN_EVENT_TABLE(Scrubber::Forwarder, wxEvtHandler)
+   EVT_MOUSE_EVENTS(Scrubber::Forwarder::OnMouse)
 END_EVENT_TABLE()
 
 static_assert(nMenuItems == 4, "wrong number of items");
diff --git a/src/tracks/ui/Scrubbing.h b/src/tracks/ui/Scrubbing.h
index 9f83ea8f6..35c339931 100644
--- a/src/tracks/ui/Scrubbing.h
+++ b/src/tracks/ui/Scrubbing.h
@@ -91,7 +91,18 @@ private:
    void OnActivateOrDeactivateApp(wxActivateEvent & event);
    void UncheckAllMenuItems();
    void CheckMenuItem();
-   void OnMouse(wxMouseEvent &event);
+
+   // I need this because I can't push the scrubber as an event handler
+   // in two places at once.
+   struct Forwarder : public wxEvtHandler {
+      Forwarder(Scrubber &scrubber_) : scrubber{ scrubber_ } {}
+
+      Scrubber &scrubber;
+
+      void OnMouse(wxMouseEvent &event);
+      DECLARE_EVENT_TABLE()
+   };
+   Forwarder mForwarder{ *this };
 
 private:
    int mScrubToken;