More exception-safety for recording...

... Do not call Autosave (which might fail) when recovering from exceptions in
recording, but rely on the last good Autosave that happened during recording.

If dropout labels are needed, then immediately modify the undo history item, but
we can accept it if that modification fails.

Also, be sure NOT to skip Autosave in all other places that push the undo
history.  Make Autosave the default unless otherwise specified.

Finally removed one unnecessary call to Autosave.

src/ProjectAudioManager.cpp

@@ -28,6 +28,7 @@ Paul Licameli split from ProjectManager.cpp
 #include "ProjectStatus.h"
 #include "TimeTrack.h"
 #include "TrackPanelAx.h"
+#include "UndoManager.h"
 #include "ViewInfo.h"
 #include "WaveTrack.h"
 #include "toolbars/ToolManager.h"
@@ -870,6 +871,24 @@ void ProjectAudioManager::OnAudioIOStopRecording()
    // Only push state if we were capturing and not monitoring
    if (projectAudioIO.GetAudioIOToken() > 0)
    {
+      auto &history = ProjectHistory::Get( project );
+
+      if (IsTimerRecordCancelled()) {
+         // discard recording
+         history.RollbackState();
+         // Reset timer record
+         ResetTimerRecordCancelled();
+      }
+      else {
+         // Add to history
+         // We want this to have NOFAIL-GUARANTEE if we get here from exception
+         // handling of recording, and that means we rely on the last autosave
+         // successully committed to the database, not risking a failure
+         history.PushState(XO("Recorded Audio"), XO("Record"),
+            UndoPush::NOAUTOSAVE);
+
+         // Now, we may add a label track to give information about
+         // dropouts.  We allow failure of this.
          auto &tracks = TrackList::Get( project );
          auto gAudioIO = AudioIO::Get();
          auto &intervals = gAudioIO->LostCaptureIntervals();
@@ -890,6 +909,9 @@ void ProjectAudioManager::OnAudioIOStopRecording()
                   SelectedRegion{ interval.first,
                      interval.first + interval.second },
                   wxString::Format(wxT("%ld"), counter++));
+
+            history.ModifyState( true ); // this might fail and throw
+
             ShowWarningDialog(&window, wxT("DropoutDetected"), XO("\
 Recorded audio was lost at the labeled locations. Possible causes:\n\
 \n\
@@ -901,22 +923,8 @@ You are saving directly to a slow external storage device\n\
                false,
                XXO("Turn off dropout detection"));
          }
-
-      auto &history = ProjectHistory::Get( project );
-
-      if (IsTimerRecordCancelled()) {
-         // discard recording
-         history.RollbackState();
-         // Reset timer record
-         ResetTimerRecordCancelled();
       }
-      else
-         // Add to history
-         history.PushState(XO("Recorded Audio"), XO("Record"));
    }
-
-   // Now we auto-save again to get the project to a "normal" state again.
-   projectFileIO.AutoSave();
 }
 
 void ProjectAudioManager::OnAudioIONewBlockFiles(const WaveTrackArray *tracks)

src/ProjectHistory.cpp

@@ -87,7 +87,7 @@ namespace {
 void ProjectHistory::PushState(
    const TranslatableString &desc, const TranslatableString &shortDesc)
 {
-   PushState(desc, shortDesc, UndoPush::AUTOSAVE);
+   PushState(desc, shortDesc, UndoPush::NONE);
 }
 
 void ProjectHistory::PushState(const TranslatableString &desc,
@@ -96,7 +96,7 @@ void ProjectHistory::PushState(const TranslatableString &desc,
 {
    auto &project = mProject;
    auto &projectFileIO = ProjectFileIO::Get( project );
-   if((flags & UndoPush::AUTOSAVE) != UndoPush::MINIMAL)
+   if((flags & UndoPush::NOAUTOSAVE) == UndoPush::NONE)
       AutoSaveOrThrow( projectFileIO );
 
    // remaining no-fail operations "commit" the changes of undo manager state

src/UndoManager.cpp

@@ -281,7 +281,7 @@ void UndoManager::PushState(const TrackList * l,
 {
    unsigned int i;
 
-   if ( ((flags & UndoPush::CONSOLIDATE) != UndoPush::MINIMAL) &&
+   if ( (flags & UndoPush::CONSOLIDATE) != UndoPush::NONE &&
        // compare full translations not msgids!
        lastAction.Translation() == longDescription.Translation() &&
        mayConsolidate ) {

src/UndoManager.h

@@ -97,9 +97,9 @@ using SpaceArray = std::vector <unsigned long long> ;
 // Default is AUTOSAVE
 // Frequent/faster actions use CONSOLIDATE
 enum class UndoPush : unsigned char {
-   MINIMAL = 0,
+   NONE = 0,
    CONSOLIDATE = 1 << 0,
-   AUTOSAVE = 1 << 1
+   NOAUTOSAVE = 1 << 1
 };
 
 inline UndoPush operator | (UndoPush a, UndoPush b)
@@ -126,7 +126,7 @@ class AUDACITY_DLL_API UndoManager final
                   const std::shared_ptr<Tags> &tags,
                   const TranslatableString &longDescription,
                   const TranslatableString &shortDescription,
-                  UndoPush flags = UndoPush::AUTOSAVE);
+                  UndoPush flags = UndoPush::NONE);
    void ModifyState(const TrackList * l,
                     const SelectedRegion &selectedRegion, const std::shared_ptr<Tags> &tags);
    void ClearStates();

src/menus/TrackMenus.cpp

@@ -168,7 +168,7 @@ void DoPanTracks(AudacityProject &project, float PanValue)
    for (auto left : count == 0 ? range : selectedRange )
       left->SetPan( PanValue );
 
-   auto flags = UndoPush::AUTOSAVE;
+   auto flags = UndoPush::NONE;
    ProjectHistory::Get( project )
       /*i18n-hint: One or more audio tracks have been panned*/
       .PushState(XO("Panned audio track(s)"), XO("Pan Track"), flags);
@@ -799,7 +799,7 @@ void OnResample(const CommandContext &context)
    }
 
    int ndx = 0;
-   auto flags = UndoPush::AUTOSAVE;
+   auto flags = UndoPush::NONE;
    for (auto wt : tracks.Selected< WaveTrack >())
    {
       auto msg = XO("Resampling track %d").Format( ++ndx );

src/tracks/playabletrack/notetrack/ui/StretchHandle.cpp

@@ -261,7 +261,7 @@ UIHandle::Result StretchHandle::Release
       or present tense is fine here.  If unsure, go for whichever is
       shorter.*/
       XO("Stretch"),
-      UndoPush::CONSOLIDATE | UndoPush::AUTOSAVE);
+      UndoPush::CONSOLIDATE);
    return RefreshAll;
 }
 

src/tracks/playabletrack/wavetrack/ui/SampleHandle.cpp

@@ -422,7 +422,7 @@ UIHandle::Result SampleHandle::Release
    mClickedTrack.reset();       //Set this to NULL so it will catch improper drag events.
    ProjectHistory::Get( *pProject ).PushState(XO("Moved Samples"),
       XO("Sample Edit"),
-      UndoPush::CONSOLIDATE | UndoPush::AUTOSAVE);
+      UndoPush::CONSOLIDATE);
 
    // No change to draw since last drag
    return RefreshCode::RefreshNone;

src/tracks/ui/TimeShiftHandle.cpp

@@ -837,7 +837,7 @@ UIHandle::Result TimeShiftHandle::Release
       consolidate = true;
    }
    ProjectHistory::Get( *pProject ).PushState(msg, XO("Time-Shift"),
-      consolidate ? (UndoPush::CONSOLIDATE) : (UndoPush::AUTOSAVE));
+      consolidate ? (UndoPush::CONSOLIDATE) : (UndoPush::NONE));
 
    return result | FixScrollbars;
 }