* ext/psych/lib/psych.rb: Adding Psych::Exception

* ext/psych/parser.c: Do not allow extern_encoding to be set twice
* test/psych/test_parser.rb: test

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27882 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 10 insertions, 0 deletions

diff --git a/ext/psych/lib/psych.rb b/ext/psych/lib/psych.rb
index 464fae499e..a73b89212c 100644
--- a/ext/psych/lib/psych.rb
+++ b/ext/psych/lib/psych.rb
@@ -94,6 +94,9 @@ module Psych
   # The version of libyaml Psych is using
   LIBYAML_VERSION = Psych.libyaml_version.join '.'
 
+  class Exception < RuntimeError
+  end
+
   ###
   # Load +yaml+ in to a Ruby data structure.  If multiple documents are
   # provided, the object contained in the first document will be returned.
diff --git a/ext/psych/parser.c b/ext/psych/parser.c
index 41260ab6f5..c8b92a0fcd 100644
--- a/ext/psych/parser.c
+++ b/ext/psych/parser.c
@@ -293,8 +293,15 @@ static VALUE parse(VALUE self, VALUE yaml)
 static VALUE set_external_encoding(VALUE self, VALUE encoding)
 {
     yaml_parser_t * parser;
+    VALUE exception;
 
     Data_Get_Struct(self, yaml_parser_t, parser);
+
+    if(parser->encoding) {
+	exception = rb_const_get_at(mPsych, rb_intern("Exception"));
+	rb_raise(exception, "don't set the encoding twice!");
+    }
+
     yaml_parser_set_encoding(parser, NUM2INT(encoding));
 
     return encoding;