From bc08f571dcdbc6dc87fb574df0c11df5e14f449a Mon Sep 17 00:00:00 2001
From: Paul Licameli <paul.licameli@audacityteam.org>
Date: Sat, 23 Feb 2019 14:37:57 -0500
Subject: [PATCH] ChoiceSetting default is changeable and can be unspecified

---
 src/Prefs.cpp             | 28 +++++++++++++++++++++++-----
 src/Prefs.h               | 13 +++++++------
 src/prefs/TracksPrefs.cpp |  2 +-
 3 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/src/Prefs.cpp b/src/Prefs.cpp
index 566a22f75..63df6d719 100755
--- a/src/Prefs.cpp
+++ b/src/Prefs.cpp
@@ -276,6 +276,14 @@ const wxArrayStringEx &EnumValueSymbols::GetInternals() const
 }
 
 //////////
+const EnumValueSymbol &ChoiceSetting::Default() const
+{
+   if ( mDefaultSymbol >= 0 && mDefaultSymbol < mSymbols.size() )
+      return mSymbols[ mDefaultSymbol ];
+   static EnumValueSymbol empty;
+   return empty;
+}
+
 wxString ChoiceSetting::Read() const
 {
    const auto &defaultValue = Default().Internal();
@@ -321,7 +329,7 @@ bool ChoiceSetting::Write( const wxString &value )
 EnumSetting::EnumSetting(
    const wxString &key,
    EnumValueSymbols symbols,
-   size_t defaultSymbol,
+   long defaultSymbol,
 
    std::vector<int> intValues, // must have same size as symbols
    const wxString &oldKey
@@ -337,6 +345,14 @@ EnumSetting::EnumSetting(
    }
 }
 
+void ChoiceSetting::SetDefault( long value )
+{
+   if ( value < (long)mSymbols.size() )
+      mDefaultSymbol = value;
+   else
+      wxASSERT( false );
+}
+
 int EnumSetting::ReadInt() const
 {
    auto index = Find( Read() );
@@ -361,12 +377,14 @@ void EnumSetting::Migrate( wxString &value )
       // Do not DELETE the old key -- let that be read if user downgrades
       // Audacity.  But further changes will be stored only to the NEW key
       // and won't be seen then.
-      auto index = FindInt( intValue );
+      auto index = (long) FindInt( intValue );
       if ( index >= mSymbols.size() )
          index = mDefaultSymbol;
-      value = mSymbols[index].Internal();
-      Write(value);
-      gPrefs->Flush();
+      if ( index >= 0 && index < mSymbols.size() ) {
+         value = mSymbols[index].Internal();
+         Write(value);
+         gPrefs->Flush();
+      }
    }
 }
 
diff --git a/src/Prefs.h b/src/Prefs.h
index 5b7849c35..eec87f36b 100644
--- a/src/Prefs.h
+++ b/src/Prefs.h
@@ -127,7 +127,7 @@ public:
    ChoiceSetting(
       const wxString &key,
       EnumValueSymbols symbols,
-      size_t defaultSymbol
+      long defaultSymbol = -1
    )
       : mKey{ key }
 
@@ -135,17 +135,18 @@ public:
 
       , mDefaultSymbol{ defaultSymbol }
    {
-      wxASSERT( defaultSymbol < mSymbols.size() );
+      wxASSERT( defaultSymbol < (long)mSymbols.size() );
    }
 
    const wxString &Key() const { return mKey; }
-   const EnumValueSymbol &Default() const
-      { return mSymbols[mDefaultSymbol]; }
+   const EnumValueSymbol &Default() const;
    const EnumValueSymbols &GetSymbols() const { return mSymbols; }
 
    wxString Read() const;
    bool Write( const wxString &value ); // you flush gPrefs afterward
 
+   void SetDefault( long value );
+
 protected:
    size_t Find( const wxString &value ) const;
    virtual void Migrate( wxString& );
@@ -157,7 +158,7 @@ protected:
    // stores an internal value
    mutable bool mMigrated { false };
 
-   const size_t mDefaultSymbol;
+   long mDefaultSymbol;
 };
 
 /// Extends ChoiceSetting with a corresponding table of integer codes
@@ -170,7 +171,7 @@ public:
    EnumSetting(
       const wxString &key,
       EnumValueSymbols symbols,
-      size_t defaultSymbol,
+      long defaultSymbol,
 
       std::vector<int> intValues, // must have same size as symbols
       const wxString &oldKey
diff --git a/src/prefs/TracksPrefs.cpp b/src/prefs/TracksPrefs.cpp
index a22c2e82c..b06ff91cf 100644
--- a/src/prefs/TracksPrefs.cpp
+++ b/src/prefs/TracksPrefs.cpp
@@ -59,7 +59,7 @@ public:
    TracksViewModeEnumSetting(
       const wxString &key,
       EnumValueSymbols symbols,
-      size_t defaultSymbol,
+      long defaultSymbol,
 
       std::vector<int> intValues,
       const wxString &oldKey