[pan2] Fix crash at PanTreeStore::get_iter()

[Petr Kovář <pmkovar src gnome org>]

commit 366372076042687a0bf21cf72c7693e4a7c2b3d6
Author: Detlef Graef <detlef graef yahoo de>
Date:   Wed Jan 13 16:59:35 2016 +0100

    Fix crash at PanTreeStore::get_iter()

 pan/gui/gui.cc      |    2 +-
 pan/gui/prefs-ui.cc |    2 +-
 pan/gui/prefs.cc    |    6 ++++--
 pan/gui/prefs.h     |    2 +-
 4 files changed, 7 insertions(+), 5 deletions(-)
---
diff --git a/pan/gui/gui.cc b/pan/gui/gui.cc
index d709608..da7b5e7 100644
--- a/pan/gui/gui.cc
+++ b/pan/gui/gui.cc
@@ -2022,7 +2022,7 @@ void GUI :: do_read_selected_group ()
     // update iconv handler
     const char * from = g_mime_charset_iconv_name(local.c_str());
     char buf[256];
-    g_snprintf(buf, sizeof(buf), "%s//IGNORE", _prefs.get_string("default-charset", "UTF-8").c_str());
+    g_snprintf(buf, sizeof(buf), "%s//IGNORE", _prefs.get_string("default-charset", "UTF-8").str);
     const char * to  = g_mime_charset_iconv_name(buf);
     {
       if (iconv_inited)
diff --git a/pan/gui/prefs-ui.cc b/pan/gui/prefs-ui.cc
index 23dc212..57f45bf 100644
--- a/pan/gui/prefs-ui.cc
+++ b/pan/gui/prefs-ui.cc
@@ -343,7 +343,7 @@ namespace pan
   {
     GtkWidget * t = gtk_entry_new();
     g_object_set_data_full (G_OBJECT(t), PREFS_KEY, g_strdup(key), g_free);
-    gtk_entry_set_text (GTK_ENTRY(t), prefs.get_string (key, fallback).c_str());
+    gtk_entry_set_text (GTK_ENTRY(t), prefs.get_string (key, fallback).str);
     g_signal_connect (t, "changed", G_CALLBACK(entry_changed_cb), &prefs);
     return t;
   }
diff --git a/pan/gui/prefs.cc b/pan/gui/prefs.cc
index 5d21af7..95700a8 100644
--- a/pan/gui/prefs.cc
+++ b/pan/gui/prefs.cc
@@ -324,12 +324,14 @@ Prefs :: set_long64 (const StringView& key, uint64_t value)
 ****  STRINGS
 ***/
 
-std::string
+StringView
 Prefs :: get_string (const StringView& key, const StringView& fallback) const
 {
+  StringView prefs_string;
   if (!_strings.count (key))
     _strings[key] = fallback;
-  return _strings[key];
+  prefs_string = _strings[key];
+  return prefs_string;
 }
 
 void
diff --git a/pan/gui/prefs.h b/pan/gui/prefs.h
index 748834a..eac865e 100644
--- a/pan/gui/prefs.h
+++ b/pan/gui/prefs.h
@@ -103,7 +103,7 @@ namespace pan
       uint64_t get_long64 (const StringView& key, uint64_t fallback) const;
       void set_long64 (const StringView& key, uint64_t value);
 
-      std::string get_string (const StringView& key, const StringView& fallback) const;
+      StringView get_string (const StringView& key, const StringView& fallback) const;
       void set_string (const StringView& key, const StringView&);
 
       void set_color (const StringView& key, const GdkColor& color);