testing new non-autotools build system

[chaz/yoink] / src / stlplus / persistence / persistent_interface.tpp

diff --git a/src/stlplus/persistence/persistent_interface.tpp b/src/stlplus/persistence/persistent_interface.tpp
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+++ b/src/stlplus/persistence/persistent_interface.tpp
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+////////////////////////////////////////////////////////////////////////////////\r
+\r
+//   Author:    Andy Rushton\r
+//   Copyright: (c) Southampton University 1999-2004\r
+//              (c) Andy Rushton           2004-2009\r
+//   License:   BSD License, see ../docs/license.html\r
+\r
+//   Polymorphous classes using the interface approach\r
+\r
+//   format: magic [ key data ]\r
+\r
+////////////////////////////////////////////////////////////////////////////////\r
+#include "persistent_int.hpp"\r
+\r
+namespace stlplus\r
+{\r
+\r
+  ////////////////////////////////////////////////////////////////////////////////\r
+\r
+  template<typename T>\r
+  void dump_interface(dump_context& context, const T* const data)\r
+    throw(persistent_dump_failed)\r
+  {\r
+    try\r
+    {\r
+      // register the address and get the magic key for it\r
+      std::pair<bool,unsigned> mapping = context.pointer_map(data);\r
+      dump_unsigned(context,mapping.second);\r
+      // if the address is null, then that is all that we need to do\r
+      // however, if it is non-null and this is the first sight of the address, dump the contents\r
+      if (data && !mapping.first)\r
+      {\r
+        // interface method\r
+        // the lookup just finds the magic key and the type has a dump method\r
+        // this will throw persistent_illegal_type if the type is not registered\r
+        unsigned key = context.lookup_interface(typeid(*data));\r
+        // dump the magic key for the type\r
+        dump_unsigned(context, key);\r
+        // now call the dump method defined by the interface\r
+        data->dump(context);\r
+      }\r
+    }\r
+    catch (const persistent_illegal_type& except)\r
+    {\r
+      // convert this to a simpler dump failed exception\r
+      throw persistent_dump_failed(except.what());\r
+    }\r
+  }\r
+\r
+  ////////////////////////////////////////////////////////////////////////////////\r
+\r
+  template<typename T>\r
+  void restore_interface(restore_context& context, T*& data)\r
+    throw(persistent_restore_failed)\r
+  {\r
+    try\r
+    {\r
+      // first delete any previous object pointed to since the restore creates the object of the right subclass\r
+      if (data)\r
+      {\r
+        delete data;\r
+        data = 0;\r
+      }\r
+      // get the magic key\r
+      unsigned magic = 0;\r
+      restore_unsigned(context,magic);\r
+      // now lookup the magic key to see if this pointer has already been restored\r
+      // null pointers are always flagged as already restored\r
+      std::pair<bool,void*> address = context.pointer_map(magic);\r
+      if (address.first)\r
+      {\r
+        // seen before, so simply map it to the existing address\r
+        data = (T*)address.second;\r
+      }\r
+      else\r
+      {\r
+        // now restore the magic key that denotes the particular subclass\r
+        unsigned key = 0;\r
+        restore_unsigned(context, key);\r
+        // interface approach\r
+        // first clone the sample object stored in the map - lookup_interface can throw persistent_illegal_type\r
+        data = (T*)(context.lookup_interface(key)->clone());\r
+        // add this pointer to the set of already seen objects\r
+        // do this before restoring the object so that self-referential structures restore correctly\r
+        context.pointer_add(magic,data);\r
+        // now restore the contents using the object's method\r
+        data->restore(context);\r
+      }\r
+    }\r
+    catch (const persistent_illegal_type& exception)\r
+    {\r
+      // convert this to a simpler dump failed exception\r
+      throw persistent_restore_failed(exception.what());\r
+    }\r
+  }\r
+\r
+  ////////////////////////////////////////////////////////////////////////////////\r
+\r
+} // end namespace stlplus\r