Use static member functions instead of static members for avoid static initialization order fiasco

Jürgen Knödlseder
1 parent b5044584
Showing 3 changed files with 47 additions and 61 deletions
include/GModelTemporalRegistry.hpp
include/GRegistry.hpp
src/model/GModelTemporalRegistry.cpp
@@ -75,14 +75,26 @@ protected:
     void free_members(void);
  
 private:
-    // Private members
-    static int                    m_number;   //!< Number of models in registry
-    static std::string*           m_names;    //!< Model names
-    static const GModelTemporal** m_models;   //!< Pointer to seed models
+    // Private members (the private members have been implement as static
+    // methods to avoid the static initialization order fiasco of static
+    // members; using static methods we follow the "construct on first use
+    // idiom")
+    //static int                    m_number;   //!< Number of models in registry
+    //static std::string*           m_names;    //!< Model names
+    //static const GModelTemporal** m_models;   //!< Pointer to seed models
     //static GRegistryPointer<std::string>           m_names;
-    //static GRegistryPointer<const GModelTemporal*> m_models;
-    //static std::auto_ptr<std::string>           m_names;
-    //static std::auto_ptr<const GModelTemporal*> m_models;
+    static int& number() {
+        static int m_number = 0;
+        return m_number;
+    };
+    static GRegistryPointer<std::string>& names() {
+        static GRegistryPointer<std::string> m_names;
+        return m_names;
+    };
+    static GRegistryPointer<const GModelTemporal*>& models() {
+        static GRegistryPointer<const GModelTemporal*> m_models;
+        return m_models;
+    };
 };
  
  
@@ -96,7 +108,7 @@ private:
 inline
 int GModelTemporalRegistry::size(void) const
 {
-    return m_number;
+    return number();
 }
  
 #endif /* GMODELTEMPORALREGISTRY_HPP */
@@ -44,8 +44,8 @@ class GRegistryPointer {
  
 public:
     // Constructors and destructors
-    explicit GRegistryPointer(T* ptr = NULL) : m_ptr(ptr) { }
-    GRegistryPointer(const GRegistryPointer<T>& ptr) : m_ptr(ptr.m_ptr) {}
+    GRegistryPointer(void) : m_ptr(0) { }
+    GRegistryPointer(const GRegistryPointer<T>& ptr) : m_ptr(ptr.m_ptr) { }
     virtual ~GRegistryPointer(void) { free_members(); }
  
     // Operators
@@ -32,15 +32,6 @@
 #include "GException.hpp"
 #include "GTools.hpp"
  
-/* __ Static members _____________________________________________________ */
-int                                     GModelTemporalRegistry::m_number(0);
-std::string*           GModelTemporalRegistry::m_names(0);
-const GModelTemporal** GModelTemporalRegistry::m_models(0);
-//GRegistryPointer<std::string>           GModelTemporalRegistry::m_names(0);
-//GRegistryPointer<const GModelTemporal*> GModelTemporalRegistry::m_models(0);
-//std::auto_ptr<std::string>           GModelTemporalRegistry::m_names(0);
-//std::auto_ptr<const GModelTemporal*> GModelTemporalRegistry::m_models(0);
-
 /* __ Method name definitions ____________________________________________ */
 #define G_NAME                           "GModelTemporalRegistry::name(int&)"
  
@@ -69,9 +60,8 @@ GModelTemporalRegistry::GModelTemporalRegistry(void)
     // Debug option: Show actual registry
     #if G_DEBUG_REGISTRY
     std::cout << "GModelTemporalRegistry(void): ";
-    for (int i = 0; i < m_number; ++i) {
-        std::cout << "\"" << m_names[i] << "\" ";
-//        std::cout << "\"" << (m_names.get())[i] << "\" ";
+    for (int i = 0; i < number(); ++i) {
+        std::cout << "\"" << names()[i] << "\" ";
     }
     std::cout << std::endl;
     #endif
@@ -96,44 +86,33 @@ GModelTemporalRegistry::GModelTemporalRegistry(const GModelTemporal* model)
     std::cout << "GModelTemporalRegistry(const GModelTemporal*): ";
     std::cout << "add \"" << model->type() << "\" to registry." << std::endl;
     #endif
-    
-    // Allocate new old registry
-    std::string*           new_names  = new std::string[m_number+1];
-    const GModelTemporal** new_models = new const GModelTemporal*[m_number+1];
+
+    // Allocate new registry
+    std::string*           new_names  = new std::string[number()+1];
+    const GModelTemporal** new_models = new const GModelTemporal*[number()+1];
  
     // Save old registry
-    for (int i = 0; i < m_number; ++i) {
-        new_names[i]  = m_names[i];
-        new_models[i] = m_models[i];
-//        new_names[i]  = (m_names.get())[i];
-//        new_models[i] = (m_models.get())[i];
+    for (int i = 0; i < number(); ++i) {
+        new_names[i]  = names()[i];
+        new_models[i] = models()[i];
     }
  
     // Add new model to registry
-    new_names[m_number]  = model->type();
-    new_models[m_number] = model;
-
-    // Delete old registry
-    if (m_names  != NULL) delete [] m_names;
-    if (m_models != NULL) delete [] m_models;
+    new_names[number()]  = model->type();
+    new_models[number()] = model;
  
     // Set pointers on new registry
-    m_names  = new_names;
-    m_models = new_models;
-    //m_names.assign(new_names);
-    //m_models.assign(new_models);
-    //m_names.reset(new_names);
-    //m_models.reset(new_models);
+    names().assign(new_names);
+    models().assign(new_models);
  
     // Increment number of models in registry
-    m_number++;
+    number()++;
  
     // Debug option: Show actual registry
     #if G_DEBUG_REGISTRY
     std::cout << "GModelTemporalRegistry(const GModelTemporal*): ";
-    for (int i = 0; i < m_number; ++i) {
-        std::cout << "\"" << m_names[i] << "\" ";
-//        std::cout << "\"" << (m_names.get())[i] << "\" ";
+    for (int i = 0; i < number(); ++i) {
+        std::cout << "\"" << names()[i] << "\" ";
     }
     std::cout << std::endl;
     #endif
@@ -229,14 +208,12 @@ GModelTemporal* GModelTemporalRegistry::alloc(const std::string&amp; name) const
     GModelTemporal* model = NULL;
  
     // Search for model in registry
-    for (int i = 0; i < m_number; ++i) {
-        if (m_names[i] == name) {
-//        if ((m_names.get())[i] == name) {
-            model = m_models[i]->clone();
-//            model = (m_models.get())[i]->clone();
+    for (int i = 0; i < number(); ++i) {
+        if (names()[i] == name) {
+            model = models()[i]->clone();
             break;
         }
-    }    
+    }
  
     // Return temporal model
     return model;
@@ -262,8 +239,7 @@ std::string GModelTemporalRegistry::name(const int&amp; index) const
     #endif
  
     // Return name
-    return (m_names[index]);
-//    return ((m_names.get())[index]);
+    return (names()[index]);
 }
  
  
@@ -286,14 +262,12 @@ std::string GModelTemporalRegistry::print(const GChatter&amp; chatter) const
  
         // Append information
         result.append("\n"+gammalib::parformat("Number of models"));
-        result.append(gammalib::str(m_number));
+        result.append(gammalib::str(number()));
  
         // Append models
-        for (int i = 0; i < m_number; ++i) {
-            result.append("\n"+gammalib::parformat(m_names[i]));
-//            result.append("\n"+gammalib::parformat((m_names.get())[i]));
-            result.append(m_models[i]->type());
-//            result.append((m_models.get())[i]->type());
+        for (int i = 0; i < number(); ++i) {
+            result.append("\n"+gammalib::parformat(names()[i]));
+            result.append(models()[i]->type());
         }
  
     } // endif: chatter was not silent