statements can count parameters

ext/mysql2/statement.c

@@ -9,7 +9,6 @@ VALUE cMysql2Statement;
 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))) {
@@ -19,9 +18,22 @@ static VALUE prepare(VALUE self, VALUE sql)
   return self;
 }
 
+/* call-seq: stmt.param_count # => 2
+ *
+ * Returns the number of parameters the prepared statement expects.
+ */
+static VALUE param_count(VALUE self)
+{
+  MYSQL_STMT * stmt;
+  Data_Get_Struct(self, MYSQL_STMT, stmt);
+
+  return ULL2NUM(mysql_stmt_param_count(stmt));
+}
+
 void init_mysql2_statement()
 {
   cMysql2Statement = rb_define_class_under(mMysql2, "Statement", rb_cObject);
 
   rb_define_method(cMysql2Statement, "prepare", prepare, 1);
+  rb_define_method(cMysql2Statement, "param_count", param_count, 0);
 }

spec/mysql2/statement_spec.rb

@@ -2,7 +2,7 @@
 require 'spec_helper'
 
 describe Mysql2::Statement do
-  before :all do
+  before :each do
     @client = Mysql2::Client.new :host => "localhost", :username => "root"
   end
 
@@ -26,4 +26,13 @@ describe Mysql2::Statement do
     @client.close
     lambda { stmt.prepare 'SELECT 1' }.should raise_error(Mysql2::Error)
   end
+
+  it "should tell us the param count" do
+    stmt = @client.create_statement
+    stmt.prepare 'SELECT ?, ?'
+    stmt.param_count.should == 2
+
+    stmt.prepare 'SELECT 1'
+    stmt.param_count.should == 0
+  end
 end