we can prepare statements!

ext/mysql2/mysql2_ext.c

@@ -455,6 +455,21 @@ static VALUE init_connection(VALUE self)
   return self;
 }
 
+/* call-seq: client.create_statement # => Mysql2::Statement
+ *
+ * Create a new prepared statement.
+ */
+static VALUE create_statement(VALUE self)
+{
+  MYSQL * client;
+  MYSQL_STMT * stmt;
+
+  Data_Get_Struct(self, MYSQL, client);
+  stmt = mysql_stmt_init(client);
+
+  return Data_Wrap_Struct(cMysql2Statement, 0, mysql_stmt_close, stmt);
+}
+
 /* Ruby Extension initializer */
 void Init_mysql2() {
   mMysql2 = rb_define_module("Mysql2");
@@ -471,6 +486,7 @@ void Init_mysql2() {
   rb_define_method(cMysql2Client, "async_result", rb_mysql_client_async_result, 0);
   rb_define_method(cMysql2Client, "last_id", rb_mysql_client_last_id, 0);
   rb_define_method(cMysql2Client, "affected_rows", rb_mysql_client_affected_rows, 0);
+  rb_define_method(cMysql2Client, "create_statement", create_statement, 0);
 
   rb_define_private_method(cMysql2Client, "reconnect=", set_reconnect, 1);
   rb_define_private_method(cMysql2Client, "connect_timeout=", set_connect_timeout, 1);
@@ -482,6 +498,7 @@ void Init_mysql2() {
   cMysql2Error = rb_const_get(mMysql2, rb_intern("Error"));
 
   init_mysql2_result();
+  init_mysql2_statement();
 
   sym_id = ID2SYM(rb_intern("id"));
   sym_version = ID2SYM(rb_intern("version"));

ext/mysql2/mysql2_ext.h

@@ -27,6 +27,7 @@
 #endif
 
 #include <result.h>
+#include <statement.h>
 
 extern VALUE mMysql2;
 

ext/mysql2/statement.c

@@ -0,0 +1,27 @@
+#include <mysql2_ext.h>
+
+VALUE cMysql2Statement;
+
+/* call-seq: stmt.prepare(sql)
+ *
+ * Prepare +sql+ for execution
+ */
+static VALUE prepare(VALUE self, VALUE sql)
+{
+  MYSQL_STMT * stmt;
+
+  Data_Get_Struct(self, MYSQL_STMT, stmt);
+
+  if(mysql_stmt_prepare(stmt, StringValuePtr(sql), RSTRING_LEN(sql))) {
+    rb_raise(cMysql2Error, "%s", mysql_stmt_error(stmt));
+  }
+
+  return self;
+}
+
+void init_mysql2_statement()
+{
+  cMysql2Statement = rb_define_class_under(mMysql2, "Statement", rb_cObject);
+
+  rb_define_method(cMysql2Statement, "prepare", prepare, 1);
+}

ext/mysql2/statement.h

@@ -0,0 +1,8 @@
+#ifndef MYSQL2_STATEMENT_H
+#define MYSQL2_STATEMENT_H
+
+extern VALUE cMysql2Statement;
+
+void init_mysql2_statement();
+
+#endif

spec/mysql2/statement_spec.rb

@@ -0,0 +1,29 @@
+# encoding: UTF-8
+require 'spec_helper'
+
+describe Mysql2::Statement do
+  before :all do
+    @client = Mysql2::Client.new :host => "localhost", :username => "root"
+  end
+
+  it "should create a statement" do
+    stmt = @client.create_statement
+    stmt.should be_kind_of Mysql2::Statement
+  end
+
+  it "prepares some sql" do
+    stmt = @client.create_statement
+    lambda { stmt.prepare 'SELECT 1' }.should_not raise_error
+  end
+
+  it "return self when prepare some sql" do
+    stmt = @client.create_statement
+    stmt.prepare('SELECT 1').should == stmt
+  end
+
+  it "should raise an exception when server disconnects" do
+    stmt = @client.create_statement
+    @client.close
+    lambda { stmt.prepare 'SELECT 1' }.should raise_error(Mysql2::Error)
+  end
+end