Bug1338 fixed again, with fewer Mac busy-waits; CHANGES WX BUILD...

... Busy-waiting will happen on Mac when modal dialogs are open, and a LADSPA,
VST, or AudioUnits effect is also open with "fancy" interface.

Busy-waiting will not happen for modal dialogs at other times.

mac/wxMac_additions/eventloops.patch

@@ -1,13 +1,79 @@
+From aed0a3ed0df16f04dc39c8366d9c399fcc172009 Mon Sep 17 00:00:00 2001
+From: Paul Licameli <paul.licameli@audacityteam.org>
+Date: Sun, 31 Jul 2016 11:55:29 -0400
+Subject: [PATCH 1/3] Mac modal loops won't hang when other code uses old
+ Mutiprocessing...
+
+... if you call the new wxEventLoopBase::SetBusyWaiting(true).
+
+But this has the undesirable consequence of high CPU usage while the loop idles,
+so this fix must be turned on only as needed by the application.
+
+See the Audacity bug report that motivated this change:
+
+http://bugzilla.audacityteam.org/show_bug.cgi?id=1338
+---
+ include/wx/evtloop.h        |  9 +++++++++
+ src/common/evtloopcmn.cpp   | 14 ++++++++++++++
+ src/osx/core/evtloop_cf.cpp |  3 ++-
+ 3 files changed, 25 insertions(+), 1 deletion(-)
+
+diff --git a/include/wx/evtloop.h b/include/wx/evtloop.h
+index 1133473..db87431 100644
+--- a/include/wx/evtloop.h
++++ b/include/wx/evtloop.h
+@@ -177,6 +177,15 @@ public:
+     // set currently active (running) event loop
+     static void SetActive(wxEventLoopBase* loop);
+ 
++#ifdef __WXMAC__
++    static bool GetBusyWaiting();
++
++    // If the argument is true, cause modal dialogs to busy-wait for events,
++    // which seems to be necessary to avoid hanging when other code is using
++    // the old Multiprocessing API
++    static void SetBusyWaiting(bool busyWaiting);
++#endif
++
+ 
+ protected:
+     // real implementation of Run()
+diff --git a/src/common/evtloopcmn.cpp b/src/common/evtloopcmn.cpp
+index f7b5138..325fd54 100644
+--- a/src/common/evtloopcmn.cpp
++++ b/src/common/evtloopcmn.cpp
+@@ -56,6 +56,20 @@ void wxEventLoopBase::SetActive(wxEventLoopBase* loop)
+         wxTheApp->OnEventLoopEnter(loop);
+ }
+ 
++static bool g_busyWaiting = false;
++
++/* static */
++bool wxEventLoopBase::GetBusyWaiting()
++{
++   return g_busyWaiting;
++}
++
++/* static */
++void wxEventLoopBase::SetBusyWaiting(bool busyWaiting)
++{
++   g_busyWaiting = busyWaiting;
++}
++
+ int wxEventLoopBase::Run()
+ {
+     // event loops are not recursive, you need to create another loop!
 diff --git a/src/osx/core/evtloop_cf.cpp b/src/osx/core/evtloop_cf.cpp
-index 7e70dec..37b22b5 100644
+index 7e70dec..510af80 100644
---- src/osx/core/evtloop_cf.cpp
+--- a/src/osx/core/evtloop_cf.cpp
-+++ src/osx/core/evtloop_cf.cpp
++++ b/src/osx/core/evtloop_cf.cpp
-@@ -243,7 +243,7 @@ int wxCFEventLoop::DoProcessEvents()
+@@ -243,7 +243,8 @@ int wxCFEventLoop::DoProcessEvents()
      }
      else
  #endif
 -        return DispatchTimeout( m_isInsideYield ? 0 : 1000 );
-+        return DispatchTimeout( 0 );
++        return DispatchTimeout
++            (m_isInsideYield || wxEventLoopBase::GetBusyWaiting() ? 0 : 1000 );
  }
  
  bool wxCFEventLoop::Dispatch()

src/effects/VST/VSTEffect.cpp

@@ -1787,6 +1787,10 @@ bool VSTEffect::HideUI()
 
 bool VSTEffect::CloseUI()
 {
+#ifdef __WXMAC__
+   wxEventLoop::SetBusyWaiting(false);
+#endif
+
    mParent->RemoveEventHandler(this);
 
    PowerOff();
@@ -2835,6 +2839,10 @@ void VSTEffect::BuildFancy()
 
    mDialog->Connect(wxEVT_SIZE, wxSizeEventHandler(VSTEffect::OnSize));
 
+#ifdef __WXMAC__
+   wxEventLoop::SetBusyWaiting(true);
+#endif
+
    return;
 }
 

src/effects/audiounits/AudioUnitEffect.cpp

@@ -22,6 +22,11 @@
 #include <wx/button.h>
 #include <wx/control.h>
 #include <wx/dir.h>
+
+#ifdef __WXMAC__
+#include <wx/evtloop.h>
+#endif
+
 #include <wx/filename.h>
 #include <wx/frame.h>
 #include <wx/listctrl.h>
@@ -1792,6 +1797,10 @@ bool AudioUnitEffect::PopulateUI(wxWindow *parent)
       }
 
       mParent->SetMinSize(wxDefaultSize);
+
+#ifdef __WXMAC__
+      wxEventLoop::SetBusyWaiting(true);
+#endif
    }
 
    mParent->PushEventHandler(this);
@@ -1838,6 +1847,10 @@ bool AudioUnitEffect::HideUI()
 
 bool AudioUnitEffect::CloseUI()
 {
+#ifdef __WXMAC__
+   wxEventLoop::SetBusyWaiting(false);
+#endif
+
    mParent->RemoveEventHandler(this);
 
    mUIHost = NULL;

src/effects/lv2/LV2Effect.cpp

@@ -18,6 +18,11 @@
 #include <wx/dcbuffer.h>
 #include <wx/dialog.h>
 #include <wx/dynarray.h>
+
+#ifdef __WXMAC__
+#include <wx/evtloop.h>
+#endif
+
 #include <wx/math.h>
 #include <wx/msgdlg.h>
 #include <wx/sizer.h>
@@ -1133,6 +1138,10 @@ bool LV2Effect::HideUI()
 
 bool LV2Effect::CloseUI()
 {
+#ifdef __WXMAC__
+   wxEventLoop::SetBusyWaiting(false);
+#endif
+
    mParent->RemoveEventHandler(this);
 
    if (mSliders)
@@ -1561,6 +1570,10 @@ bool LV2Effect::BuildFancy()
 
    TransferDataToWindow();
 
+#ifdef __WXMAC__
+   wxEventLoop::SetBusyWaiting(true);
+#endif
+
    return true;
 }