iter to stl, complete :) exposes stl-type iterators

gnucash/import-export/import-main-matcher.cpp

@@ -40,6 +40,8 @@
 
 #include <vector>
 #include <string>
+#include <optional>
+#include <iterator>
 
 #include "import-main-matcher.h"
 
@@ -193,33 +195,75 @@ defer_bal_computation (GNCImportMainMatcher *info, Account* acc)
     }
 }
 
-struct TreeViewIter
+
+// Custom iterator class
+class GtkTreeModelIterator
 {
 public:
-    TreeViewIter (GtkTreeView *view)
-        : m_model{gtk_tree_view_get_model (view)}
-        , m_value{(bool)gtk_tree_model_get_iter_first (m_model, &m_iter)}
-    {};
-    gpointer get (gint col)
+    using iterator_category = std::forward_iterator_tag;
+    using difference_type = ptrdiff_t;
+    GtkTreeModelIterator(GtkTreeModel* model, std::optional<GtkTreeIter> iter)
+        : m_model(model), m_iter(iter) {}
+    GtkTreeModelIterator& operator++()
     {
+        if (m_iter.has_value() && !gtk_tree_model_iter_next(m_model, &*m_iter))
+            m_iter = std::nullopt;
+        return *this;
+    }
+    template <typename T>
+    T get (int column) {
+        g_return_val_if_fail (m_iter.has_value(), T());
         gpointer rv;
-        gtk_tree_model_get (m_model, &m_iter, col, &rv, -1);
-        return rv;
+        gtk_tree_model_get(m_model, &*m_iter, column, &rv, -1);
+        return static_cast<T>(rv);
     }
-    GNCImportTransInfo* get_trans_info () { return static_cast<GNCImportTransInfo*>(get(DOWNLOADED_COL_DATA)); };
+    GNCImportTransInfo* get_trans_info ()
+    {
+        g_return_if_fail (m_iter.has_value(), nullptr);
+        return get<GNCImportTransInfo*>(DOWNLOADED_COL_DATA);
+    };
     std::string get_account_name ()
     {
-        auto str = static_cast<char*>(get(DOWNLOADED_COL_ACCOUNT));
+        g_return_if_fail (m_iter.has_value(), "");
+        auto str = get<char*>(DOWNLOADED_COL_ACCOUNT);
         std::string rv{str};
         g_free (str);
         return rv;
     }
-    bool has_value () { return m_value; };
-    bool next () { return (m_value = gtk_tree_model_iter_next (m_model, &m_iter)); };
+    GtkTreeModelIterator operator*() const { return *this; }
+    bool operator==(const GtkTreeModelIterator& other) const
+    {
+        if (!m_iter.has_value() && !other.m_iter.has_value())
+            return true;
+        if (!m_iter.has_value() || !other.m_iter.has_value())
+            return false;
+        return (m_model == other.m_model) &&
+               (m_iter->stamp == other.m_iter->stamp) &&
+               (m_iter->user_data == other.m_iter->user_data) &&
+               (m_iter->user_data2 == other.m_iter->user_data2) &&
+               (m_iter->user_data3 == other.m_iter->user_data3);
+    }
+    bool operator!=(const GtkTreeModelIterator& other) const { return !(*this == other); }
+private:
+    GtkTreeModel* m_model;
+    std::optional<GtkTreeIter> m_iter;
+};
+
+// Custom container class
+class GtkTreeModelContainer
+{
+public:
+    using iterator = GtkTreeModelIterator;
+    GtkTreeModelContainer(GtkTreeModel* model) : m_model(model) {}
+    iterator begin()
+    {
+        GtkTreeIter iter;
+        gtk_tree_model_get_iter_first(m_model, &iter);
+        return iterator(m_model, iter);
+    }
+    iterator end() {  return iterator(m_model, std::nullopt); }
 private:
     GtkTreeModel* m_model;
-    bool m_value;
-    GtkTreeIter m_iter;
 };
 
 void
@@ -230,7 +274,7 @@ gnc_gen_trans_list_delete (GNCImportMainMatcher *info)
         return;
 
     if (info->transaction_processed_cb)
-        for (auto iter = TreeViewIter(info->view); iter.has_value(); iter.next())
+        for (auto iter : GtkTreeModelContainer(gtk_tree_view_get_model (info->view)))
             info->transaction_processed_cb (iter.get_trans_info(), false, info->user_data);
 
     if (GTK_IS_DIALOG(info->main_widget))
@@ -281,7 +325,7 @@ gnc_gen_trans_list_show_accounts_column (GNCImportMainMatcher *info)
     std::string first_acct_name;
     bool multiple_accounts = false;
 
-    for (auto iter = TreeViewIter (info->view); iter.has_value(); iter.next())
+    for (auto iter : GtkTreeModelContainer(gtk_tree_view_get_model (info->view)))
     {
         auto acct_name = iter.get_account_name ();
         if (acct_name.empty())
@@ -434,7 +478,6 @@ resolve_conflicts (GNCImportMainMatcher *info)
         g_list_free (conflicts);
     }
 
-    for (auto iter = TreeViewIter(info->view); iter.has_value(); iter.next())
     // Refresh all
     valid = gtk_tree_model_get_iter_first (model, &import_iter);
     while (valid)
@@ -449,7 +492,7 @@ static void
 load_hash_tables (GNCImportMainMatcher *info)
 {
     GList *accounts_list = NULL;
-    for (auto iter = TreeViewIter(info->view); iter.has_value(); iter.next())
+    for (auto iter : GtkTreeModelContainer(gtk_tree_view_get_model (info->view)))
     {
         auto trans_info = iter.get_trans_info ();
         Split *s = gnc_import_TransInfo_get_fsplit (trans_info);
@@ -522,8 +565,8 @@ on_matcher_ok_clicked (GtkButton *button, GNCImportMainMatcher *info)
 
     /*   DEBUG ("Begin") */
 
-    TreeViewIter iter{info->view};
-    if (!iter.has_value())
+    GtkTreeModelContainer container(gtk_tree_view_get_model (info->view));
+    if (container.begin() == container.end())
     {
         // No transaction, we can just close the dialog.
         gnc_gen_trans_list_delete (info);
@@ -536,7 +579,7 @@ on_matcher_ok_clicked (GtkButton *button, GNCImportMainMatcher *info)
     bool first_tran = true;
     bool append_text = gtk_toggle_button_get_active ((GtkToggleButton*) info->append_text);
     GList *accounts_modified = NULL;
-    for (; iter.has_value(); iter.next())
+    for (auto iter : container)
     {
         auto trans_info{iter.get_trans_info()};
         Split* first_split = gnc_import_TransInfo_get_fsplit (trans_info);