add more robust error handling

...incl handling of secondary errors

src/lib/format-string.cpp

@@ -46,6 +46,7 @@
 
 
 #include "lib/error.hpp"
+#include "lib/format-util.hpp"
 #include "lib/format-string.hpp"
 
 #include <boost/static_assert.hpp>
@@ -68,15 +69,45 @@ namespace util {
       return reinterpret_cast<boost::format&> (*buffer);
     }
     
+    /** in case the formatting of a (primitive) value fails,
+     *  we try to use a error indicator instead
+     */
+    inline void
+    pushFailsafeReplacement (char* formatter, const char* errorMsg =NULL)
+    try {
+        string placeholder("<Error");
+        if (errorMsg){
+            placeholder += ": ";
+            placeholder += errorMsg;
+        }
+        placeholder += ">";
+        
+        accessImpl(formatter) % placeholder;
+      }
+    ERROR_LOG_AND_IGNORE (progress, "Supplying placeholder for problematic format parameter")
+    
+    
+    inline void
+    suppressInsufficientArgumentErrors (char* formatter)
+    {
+      using namespace boost::io;
+      accessImpl(formatter).exceptions (all_error_bits ^ too_few_args_bit); 
+    }
+    
+    
   }//(End) implementation details
   
   
+  
+  
+  
   /** */
   _Fmt::_Fmt (string formatString)
   {
     BOOST_STATIC_ASSERT (sizeof(boost::format) <= FORMATTER_SIZE);
     
     new(formatter_) boost::format(formatString);
+    suppressInsufficientArgumentErrors (formatter_);
   }
   
   _Fmt::~_Fmt ()
@@ -86,8 +117,8 @@ namespace util {
   
   
   /** @internal access points for the frontend,
-   * allowing to push a parameter value down into
-   * the implementation for the actual formatting.
+   * allowing to push a parameter value down into the implementation
+   * for the actual formatting.
    * @note we need to generate instantiations of this template function
    *       explicitly for all basic types to be supported for direct handling,
    *       otherwise we'll get linker errors. Lumiera uses the ``inclusion model''
@@ -98,18 +129,38 @@ namespace util {
   template<typename VAL>
   void
   _Fmt::pushParameter (VAL const& val)
-  {
-    accessImpl(formatter_) % val;
-  }
+  try {
+      accessImpl(formatter_) % val;
+    }
+  
+  catch (boost::io::too_many_args& argErr)
+    {
+      WARN (progress, "Format: excess argument '%s' of type %s ignored."
+                    , cStr(str(val))
+                    , cStr(tyStr(val)));
+    }
+  catch (std::exception& failure)
+    {
+      WARN (progress, "Format: Parameter '%s' causes problems: %s"
+                    , cStr(str(val))
+                    , failure.what());
+      pushFailsafeReplacement (formatter_, failure.what());
+    }
+  catch (...)
+    {
+      WARN (progress, "Format: Unexpected problems accepting format parameter '%s'", cStr(str(val)));
+      pushFailsafeReplacement (formatter_);
+    }
+  
   
   template<typename VAL>
   void
   _Fmt::pushParameter (const VAL * const pVal)
   {
     if (pVal)
-      pushParameter(*pVal);
+      pushParameter (*pVal);
     else
-      pushParameter(string("(null)"));
+      pushParameter (string("<null>"));
   }
   
   template<>
@@ -157,21 +208,44 @@ namespace util {
    * are evaluated and formatted prior to receiving the formatted result
    */
   _Fmt::operator string()  const
-  {
-    return accessImpl(formatter_).str();
-  }
+  try {
+      return accessImpl(formatter_).str();
+    }
+  
+  catch (std::exception& failure)
+    {
+      WARN (progress, "Format: Failure to receive formatted result: %s", failure.what());
+      return "<formatting failure>";
+    }
+  catch (...)
+    {
+      WARN (progress, "Format: Unexpected problems while formatting output.");
+      return "<unexpected problems>";
+    }
+  
   
   
   /** send the formatted buffer directly to the output stream.
    * @note this is more efficient than creating a string and outputting that,
-   *       because boost::format internally uses a stringstream to generate
+   *       because boost::format internally uses a string-stream to generate
    *       the formatted representation, relying on the C++ output framework
    */
   std::ostream&
   operator<< (std::ostream& os, _Fmt const& fmt)
-  {
-    return os << accessImpl(fmt.formatter_);
-  }
+  try {
+      return os << accessImpl(fmt.formatter_);
+    }
+  
+  catch(std::exception& failure)
+    {
+      WARN (progress, "Format: Failure when outputting formatted result: %s", failure.what());
+      return os << "<formatting failure>";
+    }
+  catch(...)
+    {
+      WARN (progress, "Format: Unexpected problems while producing formatted output.");
+      return os << "<unexpected problems>";
+    }
   
   
   

src/lib/format-string.hpp

@@ -201,7 +201,11 @@ namespace util {
     _log_and_stringify (std::exception const& ex)
     {
       WARN (progress, "Error while invoking custom string conversion: %s", ex.what());
-      return ex.what();
+      try {
+          return string("<string conversion failed: ")+ex.what()+">";
+        }
+      catch(...) { /* secondary errors ignored */ }
+      return "(formatting failure)";
     }
     
     inline string
@@ -209,15 +213,10 @@ namespace util {
     {
       const char* errID = lumiera_error();
       if (errID)
-        {
-          ERROR (progress, "Unknown error while invoking custom string conversion. Lumiera error flag = %s", errID);
-          return string("Unknown error in string conversion. FLAG=")+errID;
-        }
+        ERROR (progress, "Unknown error while invoking custom string conversion. Lumiera error flag = %s", errID);
       else
-        {
-          ERROR (progress, "Unknown error while invoking custom string conversion. No Lumiera error flag set.");
-          return "Unknown error in string conversion";
-        }
+        ERROR (progress, "Unknown error while invoking custom string conversion. No Lumiera error flag set.");
+      return "<Unknown error in string conversion>";
     }
     
   }//(End) guards/helpers

tests/lib/format-string-test.cpp

@@ -237,12 +237,12 @@ namespace test {
           CHECK (contains (mangledType, "Silent"));
           
           CHECK (_Fmt("!!%s!!") % v  == "!!Number-013!!");
-          CHECK (_Fmt("!!%s!!") % x  == "!!LUMIERA_ERROR_STATE:unforeseen state (encountered Fantomas).!!");
+          CHECK (_Fmt("!!%s!!") % x  == "!!<string conversion failed: LUMIERA_ERROR_STATE:unforeseen state (encountered Fantomas).>!!");
           
           CHECK (contains (_Fmt("%s") % rs1, "Silent"));
           CHECK (contains (_Fmt("%s") % rs2, "Silent"));
           
-          CHECK (_Fmt("!!%s!!") % rv  == "!!LUMIERA_ERROR_STATE:unforeseen state (encountered Fantomas).!!");
+          CHECK (_Fmt("!!%s!!") % rv  == "!!<string conversion failed: LUMIERA_ERROR_STATE:unforeseen state (encountered Fantomas).>!!");
           
           x.i_ = 42;
           CHECK (_Fmt("!!%s!!") % rv  == "!!Number-042!!");
@@ -258,6 +258,8 @@ namespace test {
           cout << _Fmt("__%d__") % 1     << endl;
           cout << _Fmt("__%d__") % 1 % 2 << endl;
           
+          const char* evil = NULL;
+          cout << _Fmt("__%d__") %  evil  << endl;
           cout << _Fmt("__%d__") % "dirt" << endl;
           cout << _Fmt("__%d__") % "1234" << endl;
           cout << _Fmt("__%d__") % "0xff" << endl;
@@ -307,7 +309,7 @@ namespace test {
           
           pv = NULL;
           vv = NULL;
-          CHECK (_Fmt("__%s__") % pv == "__(null)__");
+          CHECK (_Fmt("__%s__") % pv == "__<null>__");
           CHECK (_Fmt("__%s__") % pv == "__0__");
         }
     };