Change {Source,Binary}ErrorHandler to C++ (#403)

Added some new classes:

* BinaryErrorHandler: abstract base class
* BinaryErrorHandlerFile: writes errors to a FILE*
* SourceErrorHandler: abstract base class
* SourceErrorHandlerNop: eats all errors
* SourceErrorHandlerFile: writes errors to a FILE*

There are some specific ones as well:

* BinaryErrorHandlerAssert: used in wasm-interp to handle writing out a
  custom header with assertion "failures"; i.e. places where the error
  handler should fire.
* BinaryErrorHandlerModule: used when parsing a .wast, but there's an
  embedded binary file.

1 files changed, 2 insertions, 4 deletions

diff --git a/src/binary-reader-interpreter.cc b/src/binary-reader-interpreter.cc
index db5f9719..fcb6fede 100644
--- a/src/binary-reader-interpreter.cc
+++ b/src/binary-reader-interpreter.cc
@@ -23,6 +23,7 @@
 
 #include <vector>
 
+#include "binary-error-handler.h"
 #include "binary-reader-nop.h"
 #include "interpreter.h"
 #include "type-checker.h"
@@ -322,10 +323,7 @@ Label* BinaryReaderInterpreter::TopLabel() {
 
 bool BinaryReaderInterpreter::HandleError(uint32_t offset,
                                           const char* message) {
-  if (error_handler->on_error) {
-    return error_handler->on_error(offset, message, error_handler->user_data);
-  }
-  return false;
+  return error_handler->OnError(offset, message);
 }
 
 void WABT_PRINTF_FORMAT(2, 3)