Rename macro GetMysql2Result to GET_RESULT

Switch from DATA_PTR to Data_Get_Struct. This protects against calling
methods that need the result wrapper on hand-built Mysql2::Result
objects. They will raise a TypeError instead of segfaulting.

Author: sodabrew

ext/mysql2/result.c

@@ -50,6 +50,10 @@ static rb_encoding *binaryEncoding;
 #define MYSQL2_MIN_TIME 62171150401ULL
 #endif
 
+#define GET_RESULT(obj) \
+  mysql2_result_wrapper *wrapper; \
+  Data_Get_Struct(self, mysql2_result_wrapper, wrapper);
+
 typedef struct {
   int symbolizeKeys;
   int asArray;
@@ -141,9 +145,8 @@ static void *nogvl_stmt_fetch(void *ptr) {
 
 
 static VALUE rb_mysql_result_fetch_field(VALUE self, unsigned int idx, short int symbolize_keys) {
-  mysql2_result_wrapper * wrapper;
   VALUE rb_field;
-  GetMysql2Result(self, wrapper);
+  GET_RESULT(self);
 
   if (wrapper->fields == Qnil) {
     wrapper->numberOfFields = mysql_num_fields(wrapper->result);
@@ -231,8 +234,7 @@ static unsigned int msec_char_to_uint(char *msec_char, size_t len)
 
 static void rb_mysql_result_alloc_result_buffers(VALUE self, MYSQL_FIELD *fields) {
   unsigned int i;
-  mysql2_result_wrapper * wrapper;
-  GetMysql2Result(self, wrapper);
+  GET_RESULT(self);
 
   if (wrapper->result_buffers != NULL) return;
 
@@ -309,14 +311,13 @@ static void rb_mysql_result_alloc_result_buffers(VALUE self, MYSQL_FIELD *fields
 static VALUE rb_mysql_result_fetch_row_stmt(VALUE self, MYSQL_FIELD * fields, const result_each_args *args)
 {
   VALUE rowVal;
-  mysql2_result_wrapper *wrapper;
   unsigned int i = 0;
 
 #ifdef HAVE_RUBY_ENCODING_H
   rb_encoding *default_internal_enc;
   rb_encoding *conn_enc;
 #endif
-  GetMysql2Result(self, wrapper);
+  GET_RESULT(self);
 
 #ifdef HAVE_RUBY_ENCODING_H
   default_internal_enc = rb_default_internal_encoding();
@@ -509,7 +510,6 @@ static VALUE rb_mysql_result_fetch_row_stmt(VALUE self, MYSQL_FIELD * fields, co
 static VALUE rb_mysql_result_fetch_row(VALUE self, MYSQL_FIELD * fields, const result_each_args *args)
 {
   VALUE rowVal;
-  mysql2_result_wrapper * wrapper;
   MYSQL_ROW row;
   unsigned int i = 0;
   unsigned long * fieldLengths;
@@ -518,7 +518,7 @@ static VALUE rb_mysql_result_fetch_row(VALUE self, MYSQL_FIELD * fields, const r
   rb_encoding *default_internal_enc;
   rb_encoding *conn_enc;
 #endif
-  GetMysql2Result(self, wrapper);
+  GET_RESULT(self);
 
 #ifdef HAVE_RUBY_ENCODING_H
   default_internal_enc = rb_default_internal_encoding();
@@ -729,12 +729,11 @@ static VALUE rb_mysql_result_fetch_row(VALUE self, MYSQL_FIELD * fields, const r
 }
 
 static VALUE rb_mysql_result_fetch_fields(VALUE self) {
-  mysql2_result_wrapper * wrapper;
   unsigned int i = 0;
   short int symbolizeKeys = 0;
   VALUE defaults;
 
-  GetMysql2Result(self, wrapper);
+  GET_RESULT(self);
 
   defaults = rb_iv_get(self, "@query_options");
   Check_Type(defaults, T_HASH);
@@ -760,12 +759,11 @@ static VALUE rb_mysql_result_each_(VALUE self,
                                    VALUE(*fetch_row_func)(VALUE, MYSQL_FIELD *fields, const result_each_args *args),
                                    const result_each_args *args)
 {
-  mysql2_result_wrapper *wrapper;
   unsigned long i;
   const char *errstr;
   MYSQL_FIELD *fields = NULL;
 
-  GetMysql2Result(self, wrapper);
+  GET_RESULT(self);
 
   if (wrapper->is_streaming) {
     /* When streaming, we will only yield rows, not return them. */
@@ -850,10 +848,9 @@ static VALUE rb_mysql_result_each(int argc, VALUE * argv, VALUE self) {
   result_each_args args;
   VALUE defaults, opts, block, (*fetch_row_func)(VALUE, MYSQL_FIELD *fields, const result_each_args *args);
   ID db_timezone, app_timezone, dbTz, appTz;
-  mysql2_result_wrapper * wrapper;
   int symbolizeKeys, asArray, castBool, cacheRows, cast;
 
-  GetMysql2Result(self, wrapper);
+  GET_RESULT(self);
 
   defaults = rb_iv_get(self, "@query_options");
   Check_Type(defaults, T_HASH);
@@ -931,9 +928,8 @@ static VALUE rb_mysql_result_each(int argc, VALUE * argv, VALUE self) {
 }
 
 static VALUE rb_mysql_result_count(VALUE self) {
-  mysql2_result_wrapper *wrapper;
+  GET_RESULT(self);
 
-  GetMysql2Result(self, wrapper);
   if (wrapper->is_streaming) {
     /* This is an unsigned long per result.h */
     return ULONG2NUM(wrapper->numberOfRows);
@@ -957,7 +953,6 @@ VALUE rb_mysql_result_to_obj(VALUE client, VALUE encoding, VALUE options, MYSQL_
   VALUE obj;
   mysql2_result_wrapper * wrapper;
 
-
   obj = Data_Make_Struct(cMysql2Result, mysql2_result_wrapper, rb_mysql_result_mark, rb_mysql_result_free, wrapper);
   wrapper->numberOfFields = 0;
   wrapper->numberOfRows = 0;

ext/mysql2/result.h

@@ -25,6 +25,4 @@ typedef struct {
   unsigned long *length;
 } mysql2_result_wrapper;
 
-#define GetMysql2Result(obj, sval) (sval = (mysql2_result_wrapper*)DATA_PTR(obj));
-
 #endif

spec/mysql2/result_spec.rb

@@ -6,6 +6,14 @@
     @result = @client.query "SELECT 1"
   end
 
+  it "should raise a TypeError exception when it doesn't wrap a result set" do
+    r = Mysql2::Result.new
+    expect { r.count }.to raise_error(TypeError)
+    expect { r.fields }.to raise_error(TypeError)
+    expect { r.size }.to raise_error(TypeError)
+    expect { r.each }.to raise_error(TypeError)
+  end
+
   it "should have included Enumerable" do
     expect(Mysql2::Result.ancestors.include?(Enumerable)).to be true
   end