check for existence of and use the #as_json method to serialize an ob…

…ject (should speed up encoding in rails apps)

ext/yajl_ext.c

@@ -173,7 +173,10 @@ void yajl_encode_part(void * wrapper, VALUE obj, VALUE io) {
             status = yajl_gen_string(w->encoder, (const unsigned char *)cptr, len);
             break;
         default:
-            if (rb_respond_to(obj, intern_to_json)) {
+            if (rb_respond_to(obj, intern_as_json)) {
+                obj = rb_funcall(obj, intern_as_json, 0);
+                yajl_encode_part(w, obj, io);
+            } else if (rb_respond_to(obj, intern_to_json)) {
                 str = rb_funcall(obj, intern_to_json, 0);
                 cptr = RSTRING_PTR(str);
                 len = RSTRING_LEN(str);
@@ -886,6 +889,7 @@ void Init_yajl_ext() {
     intern_to_json = rb_intern("to_json");
     intern_to_sym = rb_intern("to_sym");
     intern_has_key = rb_intern("has_key?");
+    intern_as_json = rb_intern("as_json");
 
     sym_allow_comments = ID2SYM(rb_intern("allow_comments"));
     sym_check_utf8 = ID2SYM(rb_intern("check_utf8"));

ext/yajl_ext.h

@@ -49,7 +49,7 @@ int utf8Encoding;
 
 static VALUE cParseError, cEncodeError, mYajl, cParser, cEncoder;
 static ID intern_io_read, intern_call, intern_keys, intern_to_s,
-            intern_to_json, intern_has_key, intern_to_sym;
+            intern_to_json, intern_has_key, intern_to_sym, intern_as_json;
 static ID sym_allow_comments, sym_check_utf8, sym_pretty, sym_indent, sym_terminator, sym_symbolize_keys;
 
 #define GetParser(obj, sval) (sval = (yajl_parser_wrapper*)DATA_PTR(obj));

spec/encoding/encoding_spec.rb

@@ -3,7 +3,13 @@
 
 class Dummy2
   def to_json
-    "hawtness".dump
+    "{\"hawtness\":true}"
+  end
+end
+
+class Dummy3
+  def as_json
+    {:hawtness => true}
   end
 end
 
@@ -152,7 +158,12 @@ def to_json
 
   it "should check for and call #to_json if it exists on custom objects" do
     d = Dummy2.new
-    Yajl::Encoder.encode({:foo => d}).should eql('{"foo":"hawtness"}')
+    Yajl::Encoder.encode({:foo => d}).should eql('{"foo":{"hawtness":true}}')
+  end
+
+  it "should check for and call #as_json if it exists on custom objects" do
+    d = Dummy3.new
+    Yajl::Encoder.encode(d).should eql('{"hawtness":true}')
   end
 
   it "should encode a hash where the key and value can be symbols" do