Define movable_ptr and make_movable, use __AUDACITY_OLD_STD__ in fewer places

src/MemoryX.h

@@ -481,4 +481,19 @@ static char*THIS_FILE = __FILE__;
 #endif
 #endif
 
+// Frequently, we need to use a vector or list of unique_ptr if we can, but default
+// to shared_ptr if we can't (because containers know how to copy elements only,
+// not move them).
+#ifdef __AUDACITY_OLD_STD__
+
+template<typename T> using movable_ptr = std::shared_ptr<T>;
+#define make_movable std::make_shared
+
+#else
+
+template<typename T> using movable_ptr = std::unique_ptr<T>;
+#define make_movable std::make_unique
+
+#endif
+
 #endif // __AUDACITY_MEMORY_X_H__

src/UndoManager.cpp

@@ -265,17 +265,10 @@ void UndoManager::PushState(const TrackList * l,
 
    // Assume tags was duplicted before any changes.
    // Just save a new shared_ptr to it.
-#ifdef __AUDACITY_OLD_STD__
    stack.push_back(
-      std::make_shared<UndoStackElem>
+      make_movable<UndoStackElem>
          (std::move(tracksCopy),
             longDescription, shortDescription, selectedRegion, tags)
-#else
-   stack.emplace_back(
-      std::make_unique<UndoStackElem>
-         (std::move(tracksCopy),
-            longDescription, shortDescription, selectedRegion, tags)
-#endif
    );
 
    current++;

src/UndoManager.h

@@ -71,11 +71,7 @@ struct UndoState {
    SelectedRegion selectedRegion; // by value
 };
 
-#ifdef __AUDACITY_OLD_STD__
-using UndoStack = std::vector <std::shared_ptr<UndoStackElem>>;
-#else
-using UndoStack = std::vector <std::unique_ptr<UndoStackElem>>;
-#endif
+using UndoStack = std::vector <movable_ptr<UndoStackElem>>;
 
 using SpaceArray = std::vector <wxLongLong_t> ;
 

src/commands/CommandManager.cpp

@@ -811,7 +811,7 @@ CommandListEntry *CommandManager::NewIdentifier(const wxString & name,
 {
    {
       // Make a unique_ptr or shared_ptr as appropriate:
-      auto entry = CommandList::value_type{ safenew CommandListEntry() };
+      auto entry = make_movable<CommandListEntry>();
 
       wxString labelPrefix;
       if (!mSubMenuList.empty()) {

src/commands/CommandManager.h

@@ -83,11 +83,7 @@ using SubMenuList = std::vector < SubMenuListEntry >;
 
 // This is an array of pointers, not structures, because the hash maps also point to them,
 // so we don't want the structures to relocate with vector operations.
-#ifdef __AUDACITY_OLD_STD__
-using CommandList = std::vector < std::shared_ptr<CommandListEntry> >;
-#else
-using CommandList = std::vector < std::unique_ptr<CommandListEntry> >;
-#endif
+using CommandList = std::vector<movable_ptr<CommandListEntry>>;
 
 WX_DECLARE_STRING_HASH_MAP_WITH_DECL(CommandListEntry *, CommandNameHash, class AUDACITY_DLL_API);
 WX_DECLARE_HASH_MAP_WITH_DECL(int, CommandListEntry *, wxIntegerHash, wxIntegerEqual, CommandIDHash, class AUDACITY_DLL_API);