From cd8a19f055095a348caec1cdcbb517b38eb54fd0 Mon Sep 17 00:00:00 2001
From: Paul Licameli <paul.licameli@gmail.com>
Date: Fri, 26 Feb 2016 22:28:06 -0500
Subject: [PATCH] Define copy, move, and Swap for TrackList

---
 src/Track.cpp | 47 ++++++++++++++++++++++++++++++++++++++++++++---
 src/Track.h   | 16 +++++++++++++++-
 2 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/src/Track.cpp b/src/Track.cpp
index f536e0981..a559fc82a 100644
--- a/src/Track.cpp
+++ b/src/Track.cpp
@@ -713,6 +713,47 @@ TrackList::TrackList(bool destructorDeletesTracks)
    tail = NULL;
 }
 
+TrackList::TrackList(const TrackList &that)
+{
+   DoAssign(that);
+}
+
+TrackList& TrackList::operator= (const TrackList &that)
+{
+   this->Clear(mDestructorDeletesTracks);
+   DoAssign(that);
+   return *this;
+}
+
+TrackList::TrackList(TrackList &&that)
+{
+   Swap(that);
+}
+
+TrackList &TrackList::operator= (TrackList &&that)
+{
+   if (this != &that) {
+      this->Clear(mDestructorDeletesTracks);
+      Swap(that);
+   }
+   return *this;
+}
+
+void TrackList::DoAssign(const TrackList &that)
+{
+   mDestructorDeletesTracks = true;
+   TrackListConstIterator it(&that);
+   for (const Track *track = it.First(); track; track = it.Next())
+      Add(track->Duplicate());
+}
+
+void TrackList::Swap(TrackList &that)
+{
+   std::swap(mDestructorDeletesTracks, that.mDestructorDeletesTracks);
+   std::swap(head, that.head);
+   std::swap(tail, that.tail);
+}
+
 TrackList::~TrackList()
 {
    Clear(mDestructorDeletesTracks);
@@ -1025,7 +1066,7 @@ bool TrackList::CanMoveDown(Track * t) const
 // The complication is that the tracks are stored in a single
 // linked list, and pairs of tracks are marked only by a flag
 // in one of the tracks.
-void TrackList::Swap(TrackListNode * s1, TrackListNode * s2)
+void TrackList::SwapNodes(TrackListNode * s1, TrackListNode * s2)
 {
    Track *link;
    Track *source[4];
@@ -1092,7 +1133,7 @@ bool TrackList::MoveUp(Track * t)
    if (t) {
       Track *p = GetPrev(t, true);
       if (p) {
-         Swap((TrackListNode *)p->GetNode(), (TrackListNode *)t->GetNode());
+         SwapNodes((TrackListNode *)p->GetNode(), (TrackListNode *)t->GetNode());
          return true;
       }
    }
@@ -1105,7 +1146,7 @@ bool TrackList::MoveDown(Track * t)
    if (t) {
       Track *n = GetNext(t, true);
       if (n) {
-         Swap((TrackListNode *)t->GetNode(), (TrackListNode *)n->GetNode());
+         SwapNodes((TrackListNode *)t->GetNode(), (TrackListNode *)n->GetNode());
          return true;
       }
    }
diff --git a/src/Track.h b/src/Track.h
index f19515d29..c36e7b20f 100644
--- a/src/Track.h
+++ b/src/Track.h
@@ -383,6 +383,18 @@ class AUDACITY_DLL_API TrackList final : public wxEvtHandler
    // Create an empty TrackList
    TrackList(bool destructorDeletesTracks = false);
 
+   // Allow copy -- a deep copy that duplicates all tracks
+   TrackList(const TrackList &that);
+   TrackList &operator= (const TrackList &that);
+
+   // Allow move
+   TrackList(TrackList &&that);
+   TrackList& operator= (TrackList&&);
+
+   // Move is defined in terms of Swap
+   void Swap(TrackList &that);
+
+
    // Destructor
    virtual ~TrackList();
 
@@ -462,11 +474,13 @@ class AUDACITY_DLL_API TrackList final : public wxEvtHandler
 #endif
 
  private:
+   void DoAssign(const TrackList &that);
+       
    void RecalcPositions(const TrackListNode *node);
    void UpdatedEvent(const TrackListNode *node);
    void ResizedEvent(const TrackListNode *node);
 
-   void Swap(TrackListNode * s1, TrackListNode * s2);
+   void SwapNodes(TrackListNode * s1, TrackListNode * s2);
 
    TrackListNode *head;
    TrackListNode *tail;