[lmi-commits] [5501] Fix defect noted 20120616T1210Z

[Greg Chicares]

Revision: 5501
          http://svn.sv.gnu.org/viewvc/?view=rev&root=lmi&revision=5501
Author:   chicares
Date:     2012-06-18 18:35:29 +0000 (Mon, 18 Jun 2012)
Log Message:
-----------
Fix defect noted 20120616T1210Z

Modified Paths:
--------------
    lmi/trunk/ChangeLog
    lmi/trunk/product_data.cpp
    lmi/trunk/product_data.hpp
    lmi/trunk/xml_serializable.hpp
    lmi/trunk/xml_serializable.tpp

Modified: lmi/trunk/ChangeLog
===================================================================
--- lmi/trunk/ChangeLog 2012-06-18 17:12:30 UTC (rev 5500)
+++ lmi/trunk/ChangeLog 2012-06-18 18:35:29 UTC (rev 5501)
@@ -30316,3 +30316,20 @@
 be stored in a map (supra, at 20120616T1210Z). Privacy had been simply
 a default choice that afforded no important protective value.
 
+20120618T1712Z <address@hidden> [578]
+
+  antediluvian_stubs.cpp
+  product_data.cpp
+  product_data.hpp
+  xml_serializable.hpp
+  xml_serializable.tpp
+Add a virtual function; refactor.
+
+20120618T1835Z <address@hidden> [578]
+
+  product_data.cpp
+  product_data.hpp
+  xml_serializable.hpp
+  xml_serializable.tpp
+Fix defect noted 20120616T1210Z.
+

Modified: lmi/trunk/product_data.cpp
===================================================================
--- lmi/trunk/product_data.cpp  2012-06-18 17:12:30 UTC (rev 5500)
+++ lmi/trunk/product_data.cpp  2012-06-18 18:35:29 UTC (rev 5501)
@@ -300,12 +300,9 @@
     (xml::element const& e
     ) const
 {
-    glossed_string r;
+    value_type r;
     xml_serialize::from_xml(e, r);
-    // For the nonce, std::string is used as value_type,
-    // so one of {datum,gloss} must arbitrarily be discarded;
-    // choose the one that's less likely to mask a visible error.
-    return r.gloss();
+    return r;
 }
 
 /// This override doesn't call redintegrate_ex_ante(); that wouldn't

Modified: lmi/trunk/product_data.hpp
===================================================================
--- lmi/trunk/product_data.hpp  2012-06-18 17:12:30 UTC (rev 5500)
+++ lmi/trunk/product_data.hpp  2012-06-18 18:35:29 UTC (rev 5501)
@@ -67,6 +67,13 @@
     std::string gloss_;
 };
 
+class LMI_SO product_data;
+
+template<> struct deserialized<product_data>
+{
+    typedef glossed_string value_type;
+};
+
 /// Product data representable as strings, including filenames.
 ///
 /// This is the "master" product file: it includes the filenames of
@@ -80,8 +87,7 @@
     ,        public  xml_serializable  <product_data>
     ,        public  MemberSymbolTable <product_data>
 {
-    // For the nonce, value_type is guaranteed to be std::string.
-    typedef std::string value_type;
+    typedef deserialized<product_data>::value_type value_type;
 
     friend class PolicyDocument;
 

Modified: lmi/trunk/xml_serializable.hpp
===================================================================
--- lmi/trunk/xml_serializable.hpp      2012-06-18 17:12:30 UTC (rev 5500)
+++ lmi/trunk/xml_serializable.hpp      2012-06-18 18:35:29 UTC (rev 5501)
@@ -35,6 +35,17 @@
 #include <map>
 #include <string>
 
+/// Type of a deserialized xml element.
+///
+/// Specialize this if the intended type is not interconvertible with
+/// std::string.
+
+template<typename T>
+struct deserialized
+{
+    typedef std::string value_type;
+};
+
 /// Derive from this mixin class to use its xml serialization.
 ///
 /// Implicitly-declared special member functions do the right thing.
@@ -42,8 +53,7 @@
 template<typename T>
 class LMI_SO xml_serializable
 {
-    // For the nonce, value_type is guaranteed to be std::string.
-    typedef std::string value_type;
+    typedef typename deserialized<T>::value_type value_type;
 
   public:
     virtual ~xml_serializable();

Modified: lmi/trunk/xml_serializable.tpp
===================================================================
--- lmi/trunk/xml_serializable.tpp      2012-06-18 17:12:30 UTC (rev 5500)
+++ lmi/trunk/xml_serializable.tpp      2012-06-18 18:35:29 UTC (rev 5501)
@@ -37,6 +37,8 @@
 #include <boost/filesystem/convenience.hpp> // basename()
 #include <boost/static_assert.hpp>
 #include <boost/type_traits/is_base_and_derived.hpp>
+#include <boost/type_traits/is_same.hpp>
+#include <boost/utility/enable_if.hpp>
 
 #include <xmlwrapp/nodes_view.h>
 
@@ -222,6 +224,25 @@
     throw "Unreachable--silences a compiler diagnostic.";
 }
 
+template<typename X, typename Y>
+inline Y sfinae_cast
+    (X const& x
+    ,typename boost::enable_if<boost::is_same<X,Y> >::type* = 0
+    )
+{
+    return x;
+}
+
+template<typename X, typename Y>
+inline Y sfinae_cast
+    (X const&
+    ,typename boost::disable_if<boost::is_same<X,Y> >::type* = 0
+    )
+{
+    fatal_error() << "Impermissible type conversion." << LMI_FLUSH;
+    return Y();
+}
+
 /// Retrieve an xml element's value.
 
 template<typename T>
@@ -229,8 +250,7 @@
     (xml::element const& e
     ) const
 {
-    // For the nonce, value_type is guaranteed to be std::string.
-    return xml_lmi::get_content(e);
+    return sfinae_cast<std::string,value_type>(xml_lmi::get_content(e));
 }
 
 /// Read an xml element.
@@ -242,7 +262,10 @@
 /// xml_serialize::from_xml() does nearly the same thing, but in a
 /// type-dependent way; thus, it doesn't have the precondition above.
 /// However, the datum here has been subject to type erasure and its
-/// type is not readily unerased.
+/// type is not readily unerased. SOMEDAY !! But now that datatype is
+/// available, selectively at least, as value_type...so should
+/// from_xml() be used directly here? Or should this function be kept
+/// for parallelism with write_element()?
 ///
 /// The xml::element argument is the element to be read, which is
 /// already available through an iterator in read().
@@ -256,7 +279,7 @@
 {
     value_type v = fetch_element(e);
     redintegrate_ex_ante(file_version, name, v);
-    t()[name] = v;
+    t()[name] = sfinae_cast<value_type,std::string>(v);
 }
 
 /// Write an xml element.