Move Statement#initialize to Ruby

Move statement#initialize to Ruby so that we don't need to use C apis to
set instance variables

ext/sqlite3/statement.c

@@ -31,51 +31,33 @@ static VALUE allocate(VALUE klass)
  return TypedData_Make_Struct(klass, sqlite3StmtRuby, &statement_type, ctx);
 }
 
-/* call-seq: SQLite3::Statement.new(db, sql)
- *
- * Create a new statement attached to the given Database instance, and which
- * encapsulates the given SQL text. If the text contains more than one
- * statement (i.e., separated by semicolons), then the #remainder property
- * will be set to the trailing text.
- */
-static VALUE initialize(VALUE self, VALUE db, VALUE sql)
+static VALUE
+prepare(VALUE self, VALUE db, VALUE sql)
 {
- sqlite3RubyPtr db_ctx = sqlite3_database_unwrap(db);
- sqlite3StmtRubyPtr ctx;
- const char *tail = NULL;
- int status;
-
- StringValue(sql);
+ sqlite3RubyPtr db_ctx = sqlite3_database_unwrap(db);
+ sqlite3StmtRubyPtr ctx;
+ const char *tail = NULL;
+ int status;
 
- TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);
-
- if(!db_ctx->db)
- rb_raise(rb_eArgError, "prepare called on a closed database");
+ StringValue(sql);
 
- if(!UTF8_P(sql)) {
- sql = rb_str_export_to_enc(sql, rb_utf8_encoding());
- }
+ TypedData_Get_Struct(self, sqlite3StmtRuby, &statement_type, ctx);
 
 #ifdef HAVE_SQLITE3_PREPARE_V2
- status = sqlite3_prepare_v2(
+  status = sqlite3_prepare_v2(
 #else
- status = sqlite3_prepare(
+  status = sqlite3_prepare(
 #endif
  db_ctx->db,
  (const char *)StringValuePtr(sql),
  (int)RSTRING_LEN(sql),
  &ctx->st,
  &tail
- );
+  );
 
- CHECK(db_ctx->db, status);
+  CHECK(db_ctx->db, status);
 
- rb_iv_set(self, "@connection", db);
- rb_iv_set(self, "@remainder", rb_str_new2(tail));
- rb_iv_set(self, "@columns", Qnil);
- rb_iv_set(self, "@types", Qnil);
-
- return self;
+ return rb_str_new2(tail);
 }
 
 /* call-seq: stmt.close
@@ -432,7 +414,6 @@ void init_sqlite3_statement(void)
  cSqlite3Statement = rb_define_class_under(mSqlite3, "Statement", rb_cObject);
 
  rb_define_alloc_func(cSqlite3Statement, allocate);
- rb_define_method(cSqlite3Statement, "initialize", initialize, 2);
  rb_define_method(cSqlite3Statement, "close", sqlite3_rb_close, 0);
  rb_define_method(cSqlite3Statement, "closed?", closed_p, 0);
  rb_define_method(cSqlite3Statement, "bind_param", bind_param, 2);
@@ -444,6 +425,7 @@ void init_sqlite3_statement(void)
  rb_define_method(cSqlite3Statement, "column_name", column_name, 1);
  rb_define_method(cSqlite3Statement, "column_decltype", column_decltype, 1);
  rb_define_method(cSqlite3Statement, "bind_parameter_count", bind_parameter_count, 0);
+ rb_define_private_method(cSqlite3Statement, "prepare", prepare, 2);
 
 #ifdef HAVE_SQLITE3_COLUMN_DATABASE_NAME
  rb_define_method(cSqlite3Statement, "database_name", database_name, 1);

lib/sqlite3/statement.rb

@@ -19,6 +19,23 @@ class Statement
  # this will be the empty string.
  attr_reader :remainder
 
+ # call-seq: SQLite3::Statement.new(db, sql)
+ #
+ # Create a new statement attached to the given Database instance, and which
+ # encapsulates the given SQL text. If the text contains more than one
+ # statement (i.e., separated by semicolons), then the #remainder property
+ # will be set to the trailing text.
+ def initialize(db, sql)
+ raise ArgumentError, "pepare called on a closed database" if db.closed?
+
+ sql = sql.encode(Encoding::UTF_8) if sql && sql.encoding != Encoding::UTF_8
+
+ @connection = db
+ @columns = nil
+ @types = nil
+ @remainder = prepare db, sql
+ end
+
  # Binds the given variables to the corresponding placeholders in the SQL
  # text.
  #