Merge pull request #531 from larskanis/fix-530

Fix possible segfault when creating new PG::Result

Author: larskanis

ext/pg_result.c

@@ -208,12 +208,16 @@ pg_new_result2(PGresult *result, VALUE rb_pgconn)
 
 	this = (t_pg_result *)xmalloc(sizeof(*this) +  sizeof(*this->fnames) * nfields);
 	this->pgresult = result;
+	/* Initialize connection and typemap prior to any object allocations,
+	 * to make sure valid objects are marked. */
+	this->connection = rb_pgconn;
+	this->typemap = pg_typemap_all_strings;
+	this->p_typemap = RTYPEDDATA_DATA( this->typemap );
 	this->nfields = -1;
 	this->tuple_hash = Qnil;
 	this->field_map = Qnil;
 	this->flags = 0;
 	self = TypedData_Wrap_Struct(rb_cPGresult, &pgresult_type, this);
-	RB_OBJ_WRITE(self, &this->connection, rb_pgconn);
 
 	if( result ){
 		t_pg_connection *p_conn = pg_get_connection(rb_pgconn);
@@ -227,8 +231,6 @@ pg_new_result2(PGresult *result, VALUE rb_pgconn)
 		this->p_typemap = RTYPEDDATA_DATA( this->typemap );
 		this->flags = p_conn->flags;
 	} else {
-		RB_OBJ_WRITE(self, &this->typemap, pg_typemap_all_strings);
-		this->p_typemap = RTYPEDDATA_DATA( this->typemap );
 		this->enc_idx = rb_locale_encindex();
 	}
 
@@ -1422,8 +1424,9 @@ pgresult_type_map_set(VALUE self, VALUE typemap)
 	/* Check type of method param */
 	TypedData_Get_Struct(typemap, t_typemap, &pg_typemap_type, p_typemap);
 
-	RB_OBJ_WRITE(self, &this->typemap, p_typemap->funcs.fit_to_result( typemap, self ));
-	this->p_typemap = RTYPEDDATA_DATA( this->typemap );
+	typemap = p_typemap->funcs.fit_to_result( typemap, self );
+	RB_OBJ_WRITE(self, &this->typemap, typemap);
+	this->p_typemap = RTYPEDDATA_DATA( typemap );
 
 	return typemap;
 }

ext/pg_type_map_by_column.c

@@ -287,9 +287,7 @@ pg_tmbc_init(VALUE self, VALUE conv_ary)
 			t_pg_coder *p_coder;
 			/* Check argument type and store the coder pointer */
 			TypedData_Get_Struct(obj, t_pg_coder, &pg_coder_type, p_coder);
-			if( p_coder ){
-				RB_OBJ_WRITTEN(self, Qnil, p_coder->coder_obj);
-			}
+			RB_OBJ_WRITTEN(self, Qnil, p_coder->coder_obj);
 			this->convs[i].cconv = p_coder;
 		}
 	}