More exception handling; incidentally implement TimeTrack copy/paste

src/AudacityException.cpp

@@ -50,6 +50,21 @@ MessageBoxException::~MessageBoxException()
       wxAtomicDec( sOutstandingMessages );
 }
 
+SimpleMessageBoxException::~SimpleMessageBoxException()
+{
+}
+
+wxString SimpleMessageBoxException::ErrorMessage() const
+{
+   return message;
+}
+
+std::unique_ptr< AudacityException > SimpleMessageBoxException::Move()
+{
+   return std::unique_ptr< AudacityException >
+   { safenew SimpleMessageBoxException{ std::move( *this ) } };
+}
+
 // This is meant to be invoked via wxEvtHandler::CallAfter
 void MessageBoxException::DelayedHandlerAction()
 {

src/AudacityException.h

@@ -69,6 +69,30 @@ private:
    mutable bool moved { false };
 };
 
+// MessageBoxException that shows a given, unvarying string.
+class SimpleMessageBoxException /* not final */ : public MessageBoxException
+{
+public:
+   explicit SimpleMessageBoxException( const wxString &message_,
+      const wxString &caption = wxString{} )
+      : MessageBoxException{ caption }
+      , message{ message_ }
+   {}
+   ~SimpleMessageBoxException() override;
+
+   SimpleMessageBoxException( const SimpleMessageBoxException& ) = default;
+   SimpleMessageBoxException &operator = (
+      SimpleMessageBoxException && ) PROHIBITED;
+
+   std::unique_ptr< AudacityException > Move() override;
+
+   // Format a default, internationalized error message for this exception.
+   virtual wxString ErrorMessage() const override;
+
+private:
+   wxString message;
+};
+
 struct DefaultDelayedHandlerAction
 {
    void operator () (AudacityException *pException) const

src/Benchmark.cpp

@@ -337,11 +337,14 @@ void BenchmarkDialog::OnRun( wxCommandEvent & WXUNUSED(event))
 
    // Rememebr the old blocksize, so that we can restore it later.
    auto oldBlockSize = Sequence::GetMaxDiskBlockSize();
-   const auto cleanup = finally([=]
-      { Sequence::SetMaxDiskBlockSize(oldBlockSize); }
-   );
    Sequence::SetMaxDiskBlockSize(blockSize * 1024);
 
+   const auto cleanup = finally( [&] {
+      Sequence::SetMaxDiskBlockSize(oldBlockSize);
+      gPrefs->Write(wxT("/GUI/EditClipCanMove"), editClipCanMove);
+      gPrefs->Flush();
+   } );
+
    wxBusyCursor busy;
 
    HoldPrint(true);
@@ -426,8 +429,11 @@ void BenchmarkDialog::OnRun( wxCommandEvent & WXUNUSED(event))
       if (mEditDetail)
          Printf(wxT("Cut: %d - %d \n"), x0 * chunkSize, (x0 + xlen) * chunkSize);
 
-      auto tmp = t->Cut(double (x0 * chunkSize), double ((x0 + xlen) * chunkSize));
+      Track::Holder tmp;
-      if (!tmp) {
+      try {
+         tmp = t->Cut(double (x0 * chunkSize), double ((x0 + xlen) * chunkSize));
+      }
+      catch (const AudacityException&) {
          Printf(wxT("Trial %d\n"), z);
          Printf(wxT("Cut (%d, %d) failed.\n"), (x0 * chunkSize),
                 (x0 + xlen) * chunkSize);
@@ -540,7 +546,4 @@ void BenchmarkDialog::OnRun( wxCommandEvent & WXUNUSED(event))
 
    Printf(wxT("Benchmark completed successfully.\n"));
    HoldPrint(false);
-
-   gPrefs->Write(wxT("/GUI/EditClipCanMove"), editClipCanMove);
-   gPrefs->Flush();
 }

src/FileException.h

@@ -22,7 +22,7 @@ public:
         const wxString &caption = wxString{},
         const wxFileName &renameTarget_ = {})
    : MessageBoxException{ caption }
-   , fileName{ fileName_ }, cause{ cause_ }, renameTarget{ renameTarget_ }
+   , cause{ cause_ }, fileName{ fileName_ }, renameTarget{ renameTarget_ }
    {}
 
    FileException(FileException&& that)

src/LabelTrack.cpp

@@ -2339,10 +2339,10 @@ bool LabelTrack::Save(wxTextFile * out, bool overwrite)
 Track::Holder LabelTrack::Cut(double t0, double t1)
 {
    auto tmp = Copy(t0, t1);
-   if (!tmp)
+
-      return{};
    if (!Clear(t0, t1))
-      return{};
+      //THROW_INCONSISTENCY_EXCEPTION
+      ;
 
    return tmp;
 }
@@ -2353,8 +2353,7 @@ Track::Holder LabelTrack::SplitCut(double t0, double t1)
    // SplitCut() == Copy() + SplitDelete()
 
    Track::Holder tmp = Copy(t0, t1);
-   if (!tmp)
+
-      return {};
    if (!SplitDelete(t0, t1))
       return {};
 

src/Menus.cpp

@@ -4177,7 +4177,6 @@ void AudacityProject::OnCut()
             dest = n->Copy(mViewInfo.selectedRegion.t0(),
                     mViewInfo.selectedRegion.t1());
 
-         if (dest)
          FinishCopy(n, std::move(dest), newClipboard);
       }
       n = iter.Next();
@@ -4309,7 +4308,6 @@ void AudacityProject::OnCopy()
       if (n->GetSelected()) {
          auto dest = n->Copy(mViewInfo.selectedRegion.t0(),
                  mViewInfo.selectedRegion.t1());
-         if (dest)
          FinishCopy(n, std::move(dest), newClipboard);
       }
       n = iter.Next();
@@ -4351,31 +4349,29 @@ void AudacityProject::OnPaste()
    if (c == NULL)
       return;
    Track *ff = NULL;
-   const Track *tmpSrc = NULL;
+   const Track *lastClipBeforeMismatch = NULL;
-   const Track *tmpC = NULL;
+   const Track *mismatchedClip = NULL;
-   const Track *prev = NULL;
+   const Track *prevClip = NULL;
 
    bool bAdvanceClipboard = true;
    bool bPastedSomething = false;
-   bool bTrackTypeMismatch = false;
 
    while (n && c) {
       if (n->GetSelected()) {
          bAdvanceClipboard = true;
-         if (tmpC)
+         if (mismatchedClip)
-            c = tmpC;
+            c = mismatchedClip;
          if (c->GetKind() != n->GetKind()) {
-            if (!bTrackTypeMismatch) {
+            if (!mismatchedClip) {
-               tmpSrc = prev;
+               lastClipBeforeMismatch = prevClip;
-               tmpC = c;
+               mismatchedClip = c;
             }
-            bTrackTypeMismatch = true;
             bAdvanceClipboard = false;
-            c = tmpSrc;
+            c = lastClipBeforeMismatch;
 
             // If the types still don't match...
             while (c && c->GetKind() != n->GetKind()) {
-               prev = c;
+               prevClip = c;
                c = clipIter.Next();
             }
          }
@@ -4383,7 +4379,7 @@ void AudacityProject::OnPaste()
          // Handle case where the first track in clipboard
          // is of different type than the first selected track
          if (!c) {
-            c = tmpC;
+            c = mismatchedClip;
             while (n && (c->GetKind() != n->GetKind() || !n->GetSelected()))
             {
                // Must perform sync-lock adjustment before incrementing n
@@ -4399,39 +4395,40 @@ void AudacityProject::OnPaste()
          // The last possible case for cross-type pastes: triggered when we try to
          // paste 1+ tracks from one type into 1+ tracks of another type. If
          // there's a mix of types, this shouldn't run.
-         if (!c) {
+         if (!c)
-            wxMessageBox(
+            // Throw, so that any previous changes to the project in this loop
-               _("Pasting one type of track into another is not allowed."),
+            // are discarded.
-               _("Error"), wxICON_ERROR, this);
+            throw SimpleMessageBoxException{
-            c = n;//so we don't trigger any !c conditions on our way out
+               _("Pasting one type of track into another is not allowed.")
-            break;
+            };
-         }
 
          // When trying to copy from stereo to mono track, show error and exit
          // TODO: Automatically offer user to mix down to mono (unfortunately
          //       this is not easy to implement
          if (c->GetLinked() && !n->GetLinked())
-         {
+            // Throw, so that any previous changes to the project in this loop
-            wxMessageBox(
+            // are discarded.
-               _("Copying stereo audio into a mono track is not allowed."),
+            throw SimpleMessageBoxException{
-               _("Error"), wxICON_ERROR, this);
+               _("Copying stereo audio into a mono track is not allowed.")
-            break;
+            };
-         }
 
          if (!ff)
             ff = n;
 
          Maybe<WaveTrack::Locker> locker;
          if (msClipProject != this && c->GetKind() == Track::Wave)
+            // Cause duplication of block files on disk, when copy is
+            // between projects
             locker.create(static_cast<const WaveTrack*>(c));
 
-         if (c->GetKind() == Track::Wave && n && n->GetKind() == Track::Wave)
+         wxASSERT( n && c );
+         if (c->GetKind() == Track::Wave && n->GetKind() == Track::Wave)
          {
             bPastedSomething |=
                ((WaveTrack*)n)->ClearAndPaste(t0, t1, (WaveTrack*)c, true, true);
          }
          else if (c->GetKind() == Track::Label &&
-                  n && n->GetKind() == Track::Label)
+                  n->GetKind() == Track::Label)
          {
             ((LabelTrack *)n)->Clear(t0, t1);
 
@@ -4444,6 +4441,7 @@ void AudacityProject::OnPaste()
          }
          else
          {
+            n->Clear(t0, t1);
             bPastedSomething |= n->Paste(t0, c);
          }
 
@@ -4464,7 +4462,7 @@ void AudacityProject::OnPaste()
          }
 
          if (bAdvanceClipboard){
-            prev = c;
+            prevClip = c;
             c = clipIter.Next();
          }
       } // if (n->GetSelected())
@@ -4487,7 +4485,8 @@ void AudacityProject::OnPaste()
 
       while (n) {
          if (n->GetSelected() && n->GetKind()==Track::Wave) {
-            if (c && c->GetKind() == Track::Wave) {
+            if (c) {
+               wxASSERT(c->GetKind() == Track::Wave);
                bPastedSomething |=
                   ((WaveTrack *)n)->ClearAndPaste(t0, t1, (WaveTrack *)c, true, true);
             }
@@ -4598,29 +4597,40 @@ bool AudacityProject::HandlePasteNothingSelected()
       while (pClip) {
          Maybe<WaveTrack::Locker> locker;
          if ((msClipProject != this) && (pClip->GetKind() == Track::Wave))
+            // Cause duplication of block files on disk, when copy is
+            // between projects
             locker.create(static_cast<const WaveTrack*>(pClip));
 
-         Track::Holder pNewTrack;
+         Track::Holder uNewTrack;
+         Track *pNewTrack;
          switch (pClip->GetKind()) {
          case Track::Wave:
             {
                WaveTrack *w = (WaveTrack *)pClip;
-               pNewTrack = mTrackFactory->NewWaveTrack(w->GetSampleFormat(), w->GetRate());
+               uNewTrack = mTrackFactory->NewWaveTrack(w->GetSampleFormat(), w->GetRate()),
+               pNewTrack = uNewTrack.get();
             }
             break;
 
          #ifdef USE_MIDI
          case Track::Note:
-            pNewTrack = mTrackFactory->NewNoteTrack();
+            uNewTrack = mTrackFactory->NewNoteTrack(),
+            pNewTrack = uNewTrack.get();
             break;
          #endif // USE_MIDI
 
          case Track::Label:
-            pNewTrack = mTrackFactory->NewLabelTrack();
+            uNewTrack = mTrackFactory->NewLabelTrack(),
+            pNewTrack = uNewTrack.get();
             break;
-         case Track::Time:
+         case Track::Time: {
-            pNewTrack = mTrackFactory->NewTimeTrack();
+            // Maintain uniqueness of the time track!
+            pNewTrack = GetTracks()->GetTimeTrack();
+            if (!pNewTrack)
+               uNewTrack = mTrackFactory->NewTimeTrack(),
+               pNewTrack = uNewTrack.get();
             break;
+         }
          default:
             pClip = iterClip.Next();
             continue;
@@ -4632,10 +4642,13 @@ bool AudacityProject::HandlePasteNothingSelected()
          wxUnusedVar(bResult);
 
          if (!pFirstNewTrack)
-            pFirstNewTrack = pNewTrack.get();
+            pFirstNewTrack = pNewTrack;
 
          pNewTrack->SetSelected(true);
-         FinishCopy(pClip, std::move(pNewTrack), *mTracks);
+         if (uNewTrack)
+            FinishCopy(pClip, std::move(uNewTrack), *mTracks);
+         else
+            FinishCopy(pClip, pNewTrack);
 
          pClip = iterClip.Next();
       }
@@ -4899,12 +4912,10 @@ void AudacityProject::OnDuplicate()
          // Make copies not for clipboard but for direct addition to the project
          auto dest = n->Copy(mViewInfo.selectedRegion.t0(),
                  mViewInfo.selectedRegion.t1(), false);
-         if (dest) {
          dest->Init(*n);
          dest->SetOffset(wxMax(mViewInfo.selectedRegion.t0(), n->GetOffset()));
          mTracks->Add(std::move(dest));
       }
-      }
 
       if (n == l) {
          break;
@@ -5114,9 +5125,7 @@ void AudacityProject::OnSplit()
          double sel0 = mViewInfo.selectedRegion.t0();
          double sel1 = mViewInfo.selectedRegion.t1();
 
-         dest = NULL;
+         dest = n->Copy(sel0, sel1);
-         n->Copy(sel0, sel1, &dest);
-         if (dest) {
          dest->Init(*n);
          dest->SetOffset(wxMax(sel0, n->GetOffset()));
 
@@ -5130,7 +5139,6 @@ void AudacityProject::OnSplit()
 
          newTracks.Add(dest);
       }
-      }
       n = iter.Next();
    }
 
@@ -5175,11 +5183,9 @@ void AudacityProject::OnSplitNew()
                    mViewInfo.selectedRegion.t1());
          }
 #endif
-         if (dest) {
          dest->SetOffset(wxMax(newt0, offset));
          FinishCopy(n, std::move(dest), *mTracks);
       }
-      }
 
       if (n == l) {
          break;

src/NoteTrack.cpp

@@ -435,7 +435,8 @@ int NoteTrack::GetVisibleChannels()
 Track::Holder NoteTrack::Cut(double t0, double t1)
 {
    if (t1 <= t0)
-      return{};
+      //THROW_INCONSISTENCY_EXCEPTION
+      ;
    double len = t1-t0;
 
    auto newTrack = std::make_unique<NoteTrack>(mDirManager);
@@ -457,7 +458,8 @@ Track::Holder NoteTrack::Cut(double t0, double t1)
 Track::Holder NoteTrack::Copy(double t0, double t1, bool) const
 {
    if (t1 <= t0)
-      return{};
+      //THROW_INCONSISTENCY_EXCEPTION
+      ;
    double len = t1-t0;
 
    auto newTrack = std::make_unique<NoteTrack>(mDirManager);
@@ -534,6 +536,18 @@ bool NoteTrack::Paste(double t, const Track *src)
    return true;
 }
 
+bool NoteTrack::Silence(double, double)
+{
+   // to do
+   return false;
+}
+
+bool NoteTrack::InsertSilence(double, double)
+{
+   // to do
+   return false;
+}
+
 // Call this function to manipulate the underlying sequence data. This is
 // NOT the function that handles horizontal dragging.
 bool NoteTrack::Shift(double t) // t is always seconds

src/NoteTrack.h

@@ -105,6 +105,8 @@ class AUDACITY_DLL_API NoteTrack final
    bool Trim (double t0, double t1) /* not override */;
    bool Clear(double t0, double t1) override;
    bool Paste(double t, const Track *src) override;
+   bool Silence(double t0, double t1) override;
+   bool InsertSilence(double t, double len) override;
    bool Shift(double t) /* not override */;
 
 #ifdef EXPERIMENTAL_MIDI_OUT

src/Sequence.cpp

@@ -438,7 +438,8 @@ std::unique_ptr<Sequence> Sequence::Copy(sampleCount s0, sampleCount s1) const
    }
 
    if (! ConsistencyCheck(wxT("Sequence::Copy()")))
-      return {};
+      //THROW_INCONSISTENCY_EXCEPTION
+      ;
 
    return dest;
 }
@@ -1114,6 +1115,7 @@ int Sequence::FindBlock(sampleCount pos) const
    return rval;
 }
 
+//static
 bool Sequence::Read(samplePtr buffer, sampleFormat format,
                     const SeqBlock &b, size_t blockRelativeStart, size_t len,
                     bool mayThrow)
@@ -1298,7 +1300,7 @@ struct MinMaxSumsq
 }
 
 bool Sequence::GetWaveDisplay(float *min, float *max, float *rms, int* bl,
-                              size_t len, const sampleCount *where)
+                              size_t len, const sampleCount *where) const
 {
    wxASSERT(len > 0);
    const auto s0 = std::max(sampleCount(0), where[0]);
@@ -1333,7 +1335,7 @@ bool Sequence::GetWaveDisplay(float *min, float *max, float *rms, int* bl,
 
       // Find the range of sample values for this block that
       // are in the display.
-      SeqBlock &seqBlock = mBlock[b];
+      const SeqBlock &seqBlock = mBlock[b];
       const auto start = seqBlock.start;
       nextSrcX = std::min(s1, start + seqBlock.f->GetLength());
 

src/Sequence.h

@@ -101,7 +101,7 @@ class PROFILE_DLL_API Sequence final : public XMLTagHandler{
    // bl is negative wherever data are not yet available.
    // Return true if successful.
    bool GetWaveDisplay(float *min, float *max, float *rms, int* bl,
-                       size_t len, const sampleCount *where);
+                       size_t len, const sampleCount *where) const;
 
    std::unique_ptr<Sequence> Copy(sampleCount s0, sampleCount s1) const;
    bool Paste(sampleCount s0, const Sequence *src);

src/TimeTrack.cpp

@@ -63,19 +63,23 @@ TimeTrack::TimeTrack(const std::shared_ptr<DirManager> &projDirManager, const Zo
    blankPen.SetColour(214, 214, 214);
 }
 
-TimeTrack::TimeTrack(const TimeTrack &orig):
+TimeTrack::TimeTrack(const TimeTrack &orig, double *pT0, double *pT1)
-   Track(orig)
+   : Track(orig)
    , mZoomInfo(orig.mZoomInfo)
 {
    Init(orig);	// this copies the TimeTrack metadata (name, range, etc)
 
    ///@TODO: Give Envelope:: a copy-constructor instead of this?
    mEnvelope = std::make_unique<Envelope>();
+   mEnvelope->Flatten(1.0);
    mEnvelope->SetTrackLen(DBL_MAX);
    SetInterpolateLog(orig.GetInterpolateLog()); // this calls Envelope::SetInterpolateDB
-   mEnvelope->Flatten(1.0);
    mEnvelope->SetOffset(0);
    mEnvelope->SetRange(orig.mEnvelope->GetMinValue(), orig.mEnvelope->GetMaxValue());
+   if ( pT0 && pT1 )
+      // restricted copy
+      mEnvelope->CopyFrom(orig.mEnvelope.get(), *pT0, *pT1);
+   else
       mEnvelope->Paste(0.0, orig.mEnvelope.get());
 
    ///@TODO: Give Ruler:: a copy-constructor instead of this?
@@ -103,6 +107,45 @@ TimeTrack::~TimeTrack()
 {
 }
 
+Track::Holder TimeTrack::Cut( double t0, double t1 )
+{
+   auto result = Copy( t0, t1, false );
+   Clear( t0, t1 );
+   return result;
+}
+
+Track::Holder TimeTrack::Copy( double t0, double t1, bool ) const
+{
+   auto result = std::make_unique<TimeTrack>( *this, &t0, &t1 );
+   return Track::Holder{ std::move( result ) };
+}
+
+bool TimeTrack::Clear(double t0, double t1)
+{
+   mEnvelope->CollapseRegion(t0, t1);
+   return true;
+}
+
+bool TimeTrack::Paste(double t, const Track * src)
+{
+   if (src->GetKind() != Track::Time)
+      return false;
+
+   mEnvelope->Paste(t, static_cast<const TimeTrack*>(src)->mEnvelope.get());
+   return true;
+}
+
+bool TimeTrack::Silence(double t0, double t1)
+{
+   return true;
+}
+
+bool TimeTrack::InsertSilence(double t, double len)
+{
+   mEnvelope->InsertSpace(t, len);
+   return true;
+}
+
 Track::Holder TimeTrack::Duplicate() const
 {
    return std::make_unique<TimeTrack>(*this);

src/TimeTrack.h

@@ -34,11 +34,20 @@ class TimeTrack final : public Track {
     * Envelope:: and Ruler:: members in order to copy one to the other - unfortunately both lack a
     * copy-constructor to encapsulate this.
     * @param orig The original track to copy from
+    * @param pT0 if not null, then the start of the sub-range to copy
+    * @param pT1 if not null, then the end of the sub-range to copy
     */
-   TimeTrack(const TimeTrack &orig);
+   TimeTrack(const TimeTrack &orig, double *pT0 = nullptr, double *pT1 = nullptr);
 
    virtual ~TimeTrack();
 
+   Holder Cut( double t0, double t1 ) override;
+   Holder Copy( double t0, double t1, bool forClipboard ) const override;
+   bool Clear(double t0, double t1) override;
+   bool Paste(double t, const Track * src) override;
+   bool Silence(double t0, double t1) override;
+   bool InsertSilence(double t, double len) override;
+
    // Identifying the type of track
    int GetKind() const override { return Time; }
 

src/Track.cpp

@@ -309,7 +309,6 @@ bool Track::SyncLockAdjust(double oldT1, double newT1)
          return true;
 
       auto tmp = Cut(oldT1, GetEndTime());
-      if (!tmp) return false;
 
       bool ret = Paste(newT1, tmp.get());
       wxASSERT(ret); // TODO: handle this.

src/Track.h

@@ -206,28 +206,29 @@ class AUDACITY_DLL_API Track /* not final */ : public XMLTagHandler
    // separate from the Track.
    const std::shared_ptr<DirManager> &GetDirManager() const { return mDirManager; }
 
-   // Create a NEW track and modify this track (or return null for failure)
+   // Create a NEW track and modify this track
-   virtual Holder Cut(double WXUNUSED(t0), double WXUNUSED(t1)) { return{}; }
+   // Return non-NULL or else throw
+   virtual Holder Cut(double WXUNUSED(t0), double WXUNUSED(t1)) = 0;
 
-   // Create a NEW track and don't modify this track (or return null for failure)
+   // Create a NEW track and don't modify this track
+   // Return non-NULL or else throw
    // Note that subclasses may want to distinguish tracks stored in a clipboard
    // from those stored in a project
    virtual Holder Copy
-      (double WXUNUSED(t0), double WXUNUSED(t1), bool forClipboard = true) const
+      (double WXUNUSED(t0), double WXUNUSED(t1), bool forClipboard = true) const = 0;
-   { return{}; }
 
    // Return true for success
-   virtual bool Clear(double WXUNUSED(t0), double WXUNUSED(t1)) {return false;}
+   virtual bool Clear(double WXUNUSED(t0), double WXUNUSED(t1)) = 0;
 
    // Return true for success
-   virtual bool Paste(double WXUNUSED(t), const Track * WXUNUSED(src)) {return false;}
+   virtual bool Paste(double WXUNUSED(t), const Track * WXUNUSED(src)) = 0;
 
    // This can be used to adjust a sync-lock selected track when the selection
    // is replaced by one of a different length.
    virtual bool SyncLockAdjust(double oldT1, double newT1);
 
-   virtual bool Silence(double WXUNUSED(t0), double WXUNUSED(t1)) {return false;}
+   virtual bool Silence(double WXUNUSED(t0), double WXUNUSED(t1)) = 0;
-   virtual bool InsertSilence(double WXUNUSED(t), double WXUNUSED(len)) {return false;}
+   virtual bool InsertSilence(double WXUNUSED(t), double WXUNUSED(len)) = 0;
 
    virtual int GetKind() const { return None; }
 

src/WaveClip.cpp

@@ -1539,6 +1539,7 @@ void WaveClip::WriteXML(XMLWriter &xmlFile) const
 }
 
 bool WaveClip::Paste(double t0, const WaveClip* other)
+// STRONG-GUARANTEE
 {
    const bool clipNeedsResampling = other->mRate != mRate;
    const bool clipNeedsNewFormat =
@@ -1558,34 +1559,42 @@ bool WaveClip::Paste(double t0, const WaveClip* other)
          // Force sample formats to match.
          newClip->ConvertToSampleFormat(mSequence->GetSampleFormat());
       pastedClip = newClip.get();
-   } else
+   }
+   else
    {
       // No resampling or format change needed, just use original clip without making a copy
       pastedClip = other;
    }
 
+   // Paste cut lines contained in pasted clip
+   WaveClipHolders newCutlines;
+   for (const auto &cutline: pastedClip->mCutLines)
+   {
+      newCutlines.push_back(
+         make_movable<WaveClip>
+            ( *cutline, mSequence->GetDirManager(),
+              // Recursively copy cutlines of cutlines.  They don't need
+              // their offsets adjusted.
+              true));
+      newCutlines.back()->Offset(t0 - mOffset);
+   }
+
    sampleCount s0;
    TimeToSamplesClip(t0, &s0);
 
    bool result = false;
+
+   // Assume STRONG-GUARANTEE from Sequence::Paste
    if (mSequence->Paste(s0, pastedClip->mSequence.get()))
    {
+      // Assume NOFAIL-GUARANTEE in the remaining
       MarkChanged();
       mEnvelope->Paste(s0.as_double()/mRate + mOffset, pastedClip->mEnvelope.get());
       mEnvelope->RemoveUnneededPoints();
       OffsetCutLines(t0, pastedClip->GetEndTime() - pastedClip->GetStartTime());
 
-      // Paste cut lines contained in pasted clip
+      for (auto &holder : newCutlines)
-      for (const auto &cutline: pastedClip->mCutLines)
+         mCutLines.push_back(std::move(holder));
-      {
-         mCutLines.push_back(
-            make_movable<WaveClip>
-               ( *cutline, mSequence->GetDirManager(),
-                 // Recursively copy cutlines of cutlines.  They don't need
-                 // their offsets adjusted.
-                 true));
-         mCutLines.back()->Offset(t0 - mOffset);
-      }
 
       result = true;
    }
@@ -1727,7 +1736,7 @@ bool WaveClip::ClearAndAddCutLine(double t0, double t1)
 
 bool WaveClip::FindCutLine(double cutLinePosition,
                            double* cutlineStart /* = NULL */,
-                           double* cutlineEnd /* = NULL */)
+                           double* cutlineEnd /* = NULL */) const
 {
    for (const auto &cutline: mCutLines)
    {
@@ -1745,29 +1754,34 @@ bool WaveClip::FindCutLine(double cutLinePosition,
 }
 
 bool WaveClip::ExpandCutLine(double cutLinePosition)
+// STRONG-GUARANTEE
 {
-   for (auto it = mCutLines.begin(); it != mCutLines.end(); ++it)
+   auto end = mCutLines.end();
-   {
+   auto it = std::find_if( mCutLines.begin(), end,
-      WaveClip *const cutline = it->get();
+      [&](const WaveClipHolder &cutline) {
-      if (fabs(mOffset + cutline->GetOffset() - cutLinePosition) < 0.0001)
+         return fabs(mOffset + cutline->GetOffset() - cutLinePosition) < 0.0001;
-      {
+      } );
+
+   if ( it != end ) {
+      auto cutline = it->get();
+      // assume STRONG-GUARANTEE from Paste
       if (!Paste(mOffset+cutline->GetOffset(), cutline))
          return false;
       // Now erase the cutline,
       // but be careful to find it again, because Paste above may
       // have modified the array of cutlines (if our cutline contained
       // another cutline!), invalidating the iterator we had.
-         auto begin = mCutLines.begin(), end = mCutLines.end();
+      end = mCutLines.end();
-         it = std::find_if(begin, end,
+      it = std::find_if(mCutLines.begin(), end,
-            [=](decltype(*begin) &p){ return p.get() == cutline; });
+         [=](const WaveClipHolder &p) { return p.get() == cutline; });
       if (it != end)
          mCutLines.erase(it); // deletes cutline!
       else {
+         // THROW_INCONSISTENCY_EXCEPTION;
          wxASSERT(false);
       }
       return true;
    }
-   }
 
    return false;
 }
@@ -1788,6 +1802,7 @@ bool WaveClip::RemoveCutLine(double cutLinePosition)
 }
 
 void WaveClip::OffsetCutLines(double t0, double len)
+// NOFAIL-GUARANTEE
 {
    for (const auto &cutLine : mCutLines)
    {

src/WaveClip.h

@@ -141,7 +141,8 @@ public:
 class WaveClip;
 
 // Array of pointers that assume ownership
-using WaveClipHolders = std::vector < movable_ptr< WaveClip > >;
+using WaveClipHolder = movable_ptr< WaveClip >;
+using WaveClipHolders = std::vector < WaveClipHolder >;
 using WaveClipConstHolders = std::vector < movable_ptr< const WaveClip > >;
 
 // Temporary arrays of mere pointers
@@ -331,7 +332,7 @@ public:
     * position could be found. Return false otherwise. */
    bool FindCutLine(double cutLinePosition,
                     double* cutLineStart = NULL,
-                    double *cutLineEnd = NULL);
+                    double *cutLineEnd = NULL) const;
 
    /** Expand cut line (that is, re-insert audio, then DELETE audio saved in
     * cut line). Returns true if a cut line could be found and sucessfully

src/WaveTrack.cpp

@@ -532,15 +532,14 @@ bool WaveTrack::IsEmpty(double t0, double t1) const
 Track::Holder WaveTrack::Cut(double t0, double t1)
 {
    if (t1 < t0)
-      return{};
+      // THROW_INCONSISTENCY_EXCEPTION
+      ;
 
    auto tmp = Copy(t0, t1);
 
-   if (!tmp)
-      return{};
-
    if (!Clear(t0, t1))
-      return{};
+      // THROW_INCONSISTENCY_EXCEPTION
+      ;
 
    return tmp;
 }
@@ -548,14 +547,15 @@ Track::Holder WaveTrack::Cut(double t0, double t1)
 Track::Holder WaveTrack::SplitCut(double t0, double t1)
 {
    if (t1 < t0)
-      return{};
+      //THROW_INCONSISTENCY_EXCEPTION
+      ;
 
    // SplitCut is the same as 'Copy', then 'SplitDelete'
    auto tmp = Copy(t0, t1);
-   if (!tmp)
+
-      return{};
    if (!SplitDelete(t0, t1))
-      return{};
+      //THROW_INCONSISTENCY_EXCEPTION
+      ;
 
    return tmp;
 }
@@ -564,14 +564,15 @@ Track::Holder WaveTrack::SplitCut(double t0, double t1)
 Track::Holder WaveTrack::CutAndAddCutLine(double t0, double t1)
 {
    if (t1 < t0)
-      return {};
+      //THROW_INCONSISTENCY_EXCEPTION
+      ;
 
    // Cut is the same as 'Copy', then 'Delete'
    auto tmp = Copy(t0, t1);
-   if (!tmp)
+
-      return {};
    if (!ClearAndAddCutLine(t0, t1))
-      return {};
+      //THROW_INCONSISTENCY_EXCEPTION
+      ;
 
    return tmp;
 }
@@ -636,7 +637,8 @@ bool WaveTrack::Trim (double t0, double t1)
 Track::Holder WaveTrack::Copy(double t0, double t1, bool forClipboard) const
 {
    if (t1 <= t0)
-      return{};
+      //THROW_INCONSISTENCY_EXCEPTION
+      ;
 
    WaveTrack *newTrack;
    Track::Holder result
@@ -1166,8 +1168,6 @@ bool WaveTrack::SyncLockAdjust(double oldT1, double newT1)
          gPrefs->Read(wxT("/GUI/EditClipCanMove"), &clipsCanMove);
          if (clipsCanMove) {
             auto tmp = Cut (oldT1, GetEndTime() + 1.0/GetRate());
-            if (!tmp)
-               return false;
 
             ret = Paste(newT1, tmp.get());
             wxASSERT(ret);
@@ -1202,6 +1202,7 @@ bool WaveTrack::SyncLockAdjust(double oldT1, double newT1)
 }
 
 bool WaveTrack::Paste(double t0, const Track *src)
+// WEAK-GUARANTEE
 {
    bool editClipCanMove = true;
    gPrefs->Read(wxT("/GUI/EditClipCanMove"), &editClipCanMove);
@@ -1287,7 +1288,8 @@ bool WaveTrack::Paste(double t0, const Track *src)
                insideClip = clip.get();
                break;
             }
-         } else
+         }
+         else
          {
             // If clips are immovable we also allow prepending to clips
             if (clip->WithinClip(t0) ||
@@ -1312,12 +1314,11 @@ bool WaveTrack::Paste(double t0, const Track *src)
                if (clip->GetStartTime() > insideClip->GetStartTime() &&
                    insideClip->GetEndTime() + insertDuration >
                                                       clip->GetStartTime())
-               {
+                  // STRONG-GUARANTEE in case of this path
-                  wxMessageBox(
+                  // not that it matters.
-                     _("There is not enough room available to paste the selection"),
+                  throw SimpleMessageBoxException{
-                     _("Error"), wxICON_STOP);
+                     _("There is not enough room available to paste the selection")
-                  return false;
+                  };
-               }
             }
          }
 
@@ -1331,12 +1332,11 @@ bool WaveTrack::Paste(double t0, const Track *src)
    //printf("paste: multi clip mode!\n");
 
    if (!editClipCanMove && !IsEmpty(t0, t0+insertDuration-1.0/mRate))
-   {
+      // STRONG-GUARANTEE in case of this path
-      wxMessageBox(
+      // not that it matters.
-         _("There is not enough room available to paste the selection"),
+      throw SimpleMessageBoxException{
-         _("Error"), wxICON_STOP);
+         _("There is not enough room available to paste the selection")
-      return false;
+      };
-   }
 
    for (const auto &clip : other->mClips)
    {
@@ -2447,17 +2447,20 @@ void WaveTrack::UpdateLocationsCache() const
 // Expand cut line (that is, re-insert audio, then DELETE audio saved in cut line)
 bool WaveTrack::ExpandCutLine(double cutLinePosition, double* cutlineStart,
                               double* cutlineEnd)
+// STRONG-GUARANTEE
 {
    bool editClipCanMove = true;
    gPrefs->Read(wxT("/GUI/EditClipCanMove"), &editClipCanMove);
 
    // Find clip which contains this cut line
-   for (const auto &clip : mClips)
-   {
    double start = 0, end = 0;
-
+   auto pEnd = mClips.end();
-      if (clip->FindCutLine(cutLinePosition, &start, &end))
+   auto pClip = std::find_if( mClips.begin(), pEnd,
+      [&](const WaveClipHolder &clip) {
+         return clip->FindCutLine(cutLinePosition, &start, &end); } );
+   if (pClip != pEnd)
    {
+      auto &clip = *pClip;
       if (!editClipCanMove)
       {
          // We are not allowed to move the other clips, so see if there
@@ -2466,18 +2469,18 @@ bool WaveTrack::ExpandCutLine(double cutLinePosition, double* cutlineStart,
          {
             if (clip2->GetStartTime() > clip->GetStartTime() &&
                 clip->GetEndTime() + end - start > clip2->GetStartTime())
-               {
+               // STRONG-GUARANTEE in case of this path
-                  wxMessageBox(
+               throw SimpleMessageBoxException{
-                     _("There is not enough room available to expand the cut line"),
+                  _("There is not enough room available to expand the cut line")
-                     _("Error"), wxICON_STOP);
+               };
-                  return false;
-               }
           }
       }
 
       if (!clip->ExpandCutLine(cutLinePosition))
          return false;
 
+      // STRONG-GUARANTEE provided that the following gives NOFAIL-GUARANTEE
+
       if (cutlineStart)
          *cutlineStart = start;
       if (cutlineEnd)
@@ -2491,7 +2494,6 @@ bool WaveTrack::ExpandCutLine(double cutLinePosition, double* cutlineStart,
             if (clip2->GetStartTime() > clip->GetStartTime())
                clip2->Offset(end - start);
          }
-         }
 
          return true;
       }

src/effects/Effect.cpp

@@ -1278,8 +1278,6 @@ bool Effect::ProcessPass()
 {
    bool bGoodResult = true;
    bool isGenerator = GetType() == EffectTypeGenerate;
-   bool editClipCanMove;
-   gPrefs->Read(wxT("/GUI/EditClipCanMove"), &editClipCanMove, true);
 
    FloatBuffers inBuffer, outBuffer;
    ArrayOf<float *> inBufPos, outBufPos;

src/effects/Equalization.cpp

@@ -1173,8 +1173,6 @@ bool EffectEqualization::ProcessOne(int count, WaveTrack * t,
          //remove the old audio and get the NEW
          t->Clear(clipStartEndTimes[i].first,clipStartEndTimes[i].second);
          auto toClipOutput = output->Copy(clipStartEndTimes[i].first-startT+offsetT0,clipStartEndTimes[i].second-startT+offsetT0);
-         if(toClipOutput)
-         {
          //put the processed audio in
          bool bResult = t->Paste(clipStartEndTimes[i].first, toClipOutput.get());
          wxASSERT(bResult); // TO DO: Actually handle this.
@@ -1188,7 +1186,6 @@ bool EffectEqualization::ProcessOne(int count, WaveTrack * t,
             t->Join(clipRealStartEndTimes[i].first,clipRealStartEndTimes[i].second);
       }
    }
-   }
 
    return bLoopSuccess;
 }

src/effects/Equalization48x.cpp

@@ -558,8 +558,6 @@ bool EffectEqualization48x::ProcessTail(WaveTrack * t, WaveTrack * output, sampl
       t->Clear(clipStartEndTimes[i].first,clipStartEndTimes[i].second);
       //         output->Copy(clipStartEndTimes[i].first-startT+offsetT0,clipStartEndTimes[i].second-startT+offsetT0, &toClipOutput);
       auto toClipOutput = output->Copy(clipStartEndTimes[i].first-startT, clipStartEndTimes[i].second-startT);
-      if(toClipOutput)
-      {
       //put the processed audio in
       bool bResult = t->Paste(clipStartEndTimes[i].first, toClipOutput.get());
       wxASSERT(bResult); // TO DO: Actually handle this.
@@ -571,7 +569,6 @@ bool EffectEqualization48x::ProcessTail(WaveTrack * t, WaveTrack * output, sampl
          clipRealStartEndTimes[i].second >= startT+lenT) )
          t->Join(clipRealStartEndTimes[i].first,clipRealStartEndTimes[i].second);
    }
-   }
    return true;
 }