[dasher: 14/61] Generalised pre set notifications for parameters and reworked alphabet history.

[Patrick Welche <pwelche src gnome org>]

commit 7275e3d78d10e7ff241dc39e46e45fd132846907
Author: Ada Majorek <amajorek google com>
Date:   Thu Apr 7 11:12:18 2016 -0700

    Generalised pre set notifications for parameters and reworked alphabet history.
    
    fixes https://github.com/ipomoena/dasher/issues/93

 Src/DasherCore/DashIntfSettings.cpp    |    1 -
 Src/DasherCore/DasherInterfaceBase.cpp |   49 ++++++++++++++++++++-----------
 Src/DasherCore/DasherInterfaceBase.h   |   11 ++++++-
 Src/DasherCore/Observable.h            |    1 -
 Src/DasherCore/SettingsStore.cpp       |    6 ++++
 Src/DasherCore/SettingsStore.h         |    4 ++-
 Src/Win32/Widgets/StatusControl.cpp    |    6 +++-
 7 files changed, 54 insertions(+), 24 deletions(-)
---
diff --git a/Src/DasherCore/DashIntfSettings.cpp b/Src/DasherCore/DashIntfSettings.cpp
index 75e3448..6c1844d 100644
--- a/Src/DasherCore/DashIntfSettings.cpp
+++ b/Src/DasherCore/DashIntfSettings.cpp
@@ -28,6 +28,5 @@ void CDashIntfSettings::SetLongParameter(int iParameter, long lValue) {
 }
 
 void CDashIntfSettings::SetStringParameter(int iParameter, const string &strValue) {
-  CDasherInterfaceBase::PreSetNotify(iParameter, strValue);
   CDasherInterfaceBase::SetStringParameter(iParameter, strValue);
 }
diff --git a/Src/DasherCore/DasherInterfaceBase.cpp b/Src/DasherCore/DasherInterfaceBase.cpp
index e76d50a..d9bb868 100644
--- a/Src/DasherCore/DasherInterfaceBase.cpp
+++ b/Src/DasherCore/DasherInterfaceBase.cpp
@@ -81,9 +81,17 @@ static char THIS_FILE[] = __FILE__;
 #endif
 #endif
 
-CDasherInterfaceBase::CDasherInterfaceBase(CSettingsStore *pSettingsStore, CFileUtils* fileUtils) : 
CSettingsUser(pSettingsStore), m_pDasherModel(new CDasherModel()), m_pFramerate(new CFrameRate(this)), 
m_pSettingsStore(pSettingsStore), m_pLockLabel(NULL) {
+CDasherInterfaceBase::CDasherInterfaceBase(CSettingsStore *pSettingsStore, CFileUtils* fileUtils) 
+  : CSettingsUser(pSettingsStore), 
+  m_pDasherModel(new CDasherModel()), 
+  m_pFramerate(new CFrameRate(this)), 
+  m_pSettingsStore(pSettingsStore), 
+  m_pLockLabel(NULL),
+  m_preSetObserver(*pSettingsStore){
   
   pSettingsStore->Register(this);
+  pSettingsStore->PreSetObservable().Register(&m_preSetObserver);
+
   m_fileUtils = fileUtils;
   
   // Ensure that pointers to 'owned' objects are set to NULL.
@@ -195,26 +203,31 @@ CDasherInterfaceBase::~CDasherInterfaceBase() {
 
   delete m_pFramerate;
 }
-
-void CDasherInterfaceBase::PreSetNotify(int iParameter, const std::string &sNewValue) {
-  // FIXME - make this a more general 'pre-set' event in the message
-  // infrastructure
-
+void CDasherInterfaceBase::CPreSetObserver::HandleEvent(int iParameter) {
   switch(iParameter) {
   case SP_ALPHABET_ID:
+    string value = m_settingsStore.GetStringParameter(SP_ALPHABET_ID);
     // Cycle the alphabet history
-    if(GetStringParameter(SP_ALPHABET_ID) != sNewValue) {
-      if(GetStringParameter(SP_ALPHABET_1) != sNewValue) {
-        if(GetStringParameter(SP_ALPHABET_2) != sNewValue) {
-          if(GetStringParameter(SP_ALPHABET_3) != sNewValue)
-            SetStringParameter(SP_ALPHABET_4, GetStringParameter(SP_ALPHABET_3));
-          SetStringParameter(SP_ALPHABET_3, GetStringParameter(SP_ALPHABET_2));
-        }
-        SetStringParameter(SP_ALPHABET_2, GetStringParameter(SP_ALPHABET_1));
-      }
-      SetStringParameter(SP_ALPHABET_1, GetStringParameter(SP_ALPHABET_ID));
-    }
-
+    vector<string> newHistory;
+    newHistory.push_back(value);
+    string v;
+    if ((v = m_settingsStore.GetStringParameter(SP_ALPHABET_1)) != value)
+      newHistory.push_back(v);
+    if ((v = m_settingsStore.GetStringParameter(SP_ALPHABET_2)) != value)
+      newHistory.push_back(v);
+    if ((v = m_settingsStore.GetStringParameter(SP_ALPHABET_3)) != value)
+      newHistory.push_back(v);
+    if ((v = m_settingsStore.GetStringParameter(SP_ALPHABET_4)) != value)
+      newHistory.push_back(v);
+
+    // Fill empty slots. 
+    while (newHistory.size() < 4)
+      newHistory.push_back("");
+
+    m_settingsStore.SetStringParameter(SP_ALPHABET_1, newHistory[0]);
+    m_settingsStore.SetStringParameter(SP_ALPHABET_2, newHistory[1]);
+    m_settingsStore.SetStringParameter(SP_ALPHABET_3, newHistory[2]);
+    m_settingsStore.SetStringParameter(SP_ALPHABET_4, newHistory[3]);
     break;
   }
 }
diff --git a/Src/DasherCore/DasherInterfaceBase.h b/Src/DasherCore/DasherInterfaceBase.h
index ffd9be4..b5c448a 100644
--- a/Src/DasherCore/DasherInterfaceBase.h
+++ b/Src/DasherCore/DasherInterfaceBase.h
@@ -147,8 +147,6 @@ public:
 
   virtual void HandleEvent(int iParameter);
   
-  void PreSetNotify(int iParameter, const std::string &sValue);
-
   ///Locks/unlocks Dasher. The default here stores the lock message and percentage
   /// in m_strLockMessage, such that NewFrame renders this instead of the canvas
   /// if we are locked. Subclasses may override to implement better (GUI)
@@ -528,6 +526,15 @@ protected:
   /// this interface was created, as ClSet and ResetParameter need to access it.
   /// (TODO _could_ move these into CSettingsUser, but that seems uglier given so few clients?)
   CSettingsStore * const m_pSettingsStore;
+
+  class CPreSetObserver : public Observer<int> {
+    CSettingsStore& m_settingsStore;
+  public:
+    CPreSetObserver(CSettingsStore& settingsStore) : m_settingsStore(settingsStore) {};
+    void HandleEvent(int evt) override;
+  };
+
+  CPreSetObserver m_preSetObserver;
   CFileUtils* m_fileUtils;
 
   //The default expansion policy to use - an amortized policy depending on the LP_NODE_BUDGET parameter.
diff --git a/Src/DasherCore/Observable.h b/Src/DasherCore/Observable.h
index e83749c..5ddb3a0 100644
--- a/Src/DasherCore/Observable.h
+++ b/Src/DasherCore/Observable.h
@@ -22,7 +22,6 @@ public:
   Observable();
   void Register(Observer<T> *pLstnr);
   void Unregister(Observer<T> *pLstnr);
-protected:
   void DispatchEvent(T t);
 private:
   typedef typename std::list< Observer<T>* > ListenerList;
diff --git a/Src/DasherCore/SettingsStore.cpp b/Src/DasherCore/SettingsStore.cpp
index 0b24f24..2599aa0 100644
--- a/Src/DasherCore/SettingsStore.cpp
+++ b/Src/DasherCore/SettingsStore.cpp
@@ -141,6 +141,8 @@ void CSettingsStore::SetBoolParameter(int iParameter, bool bValue) {
   if(bValue == GetBoolParameter(iParameter))
     return;
 
+  pre_set_observable_.DispatchEvent(iParameter);
+
   // Set the value
   p->second.bool_value = bValue;
 
@@ -160,6 +162,8 @@ void CSettingsStore::SetLongParameter(int iParameter, long lValue) {
   if(lValue == GetLongParameter(iParameter))
     return;
 
+  pre_set_observable_.DispatchEvent(iParameter);
+
   // Set the value
   p->second.long_value = lValue;
 
@@ -179,6 +183,8 @@ void CSettingsStore::SetStringParameter(int iParameter, const std::string sValue
   if(sValue == GetStringParameter(iParameter))
     return;
 
+  pre_set_observable_.DispatchEvent(iParameter);
+
   // Set the value
   p->second.string_value = sValue;
 
diff --git a/Src/DasherCore/SettingsStore.h b/Src/DasherCore/SettingsStore.h
index 1c56795..5707d1e 100644
--- a/Src/DasherCore/SettingsStore.h
+++ b/Src/DasherCore/SettingsStore.h
@@ -36,7 +36,7 @@ namespace Dasher {
 /// The public interface uses UTF-8 strings. All Keys should be
 /// in American English and encodable in ASCII. However,
 /// string Values may contain special characters where appropriate.
-  class CSettingsStore : public Observable<int> {
+class CSettingsStore : public Observable<int> {
 public:
 
   CSettingsStore();
@@ -61,6 +61,7 @@ public:
   void AddParameters(const Settings::bp_table* table, size_t count);
   void AddParameters(const Settings::lp_table* table, size_t count);
   void AddParameters(const Settings::sp_table* table, size_t count);
+  Observable<int>& PreSetObservable() { return pre_set_observable_; }
 
 protected:
     ///Loads all (persistent) prefs from disk, using+storing default values when no
@@ -124,6 +125,7 @@ private:
   };
 
   std::unordered_map<int, Parameter> parameters_;
+  Observable<int> pre_set_observable_;
 };
   /// Superclass for anything that wants to use/access/store persistent settings.
   /// (The nearest thing remaining to the old CDasherComponent,
diff --git a/Src/Win32/Widgets/StatusControl.cpp b/Src/Win32/Widgets/StatusControl.cpp
index c1f1d5e..9f55680 100644
--- a/Src/Win32/Widgets/StatusControl.cpp
+++ b/Src/Win32/Widgets/StatusControl.cpp
@@ -10,7 +10,11 @@ CStatusControl::CStatusControl(Dasher::CSettingsUser *pCreateFrom, CAppSettings
 
 void CStatusControl::HandleEvent(int iParameter) {
        switch (iParameter) {
-       case  SP_ALPHABET_ID:
+  case  SP_ALPHABET_ID:
+  case  SP_ALPHABET_1:
+  case  SP_ALPHABET_2:
+  case  SP_ALPHABET_3:
+  case  SP_ALPHABET_4:
                PopulateCombo();
                break;
        case LP_MAX_BITRATE: