Make DatePeriod support DateTimeImmutable as well.

If the start element is a DateTimeImmutable object, then all returned objects
are also DateTimeImmutable objects. If the start element is a DateTime object,
then all returned objects are DateTime objects.

ext/date/php_date.c

@@ -385,7 +385,9 @@ const zend_function_entry date_functions[] = {
 
 	/* Advanced Interface */
 	PHP_FE(date_create, arginfo_date_create)
+	PHP_FE(date_create_immutable, arginfo_date_create)
 	PHP_FE(date_create_from_format, arginfo_date_create_from_format)
+	PHP_FE(date_create_immutable_from_format, arginfo_date_create_from_format)
 	PHP_FE(date_parse, arginfo_date_parse)
 	PHP_FE(date_parse_from_format, arginfo_date_parse_from_format)
 	PHP_FE(date_get_last_errors, arginfo_date_get_last_errors)
@@ -450,6 +452,20 @@ const zend_function_entry date_funcs_date[] = {
 	PHP_FE_END
 };
 
+const zend_function_entry date_funcs_immutable[] = {
+	PHP_ME(DateTimeImmutable, __construct,   arginfo_date_create, ZEND_ACC_CTOR|ZEND_ACC_PUBLIC)
+	PHP_ME(DateTimeImmutable, __set_state,   NULL, ZEND_ACC_PUBLIC|ZEND_ACC_STATIC)
+	PHP_ME(DateTimeImmutable, modify,        arginfo_date_method_modify, 0)
+	PHP_ME(DateTimeImmutable, add,           arginfo_date_method_add, 0)
+	PHP_ME(DateTimeImmutable, sub,           arginfo_date_method_sub, 0)
+	PHP_ME(DateTimeImmutable, setTimezone,   arginfo_date_method_timezone_set, 0)
+	PHP_ME(DateTimeImmutable, setTime,       arginfo_date_method_time_set, 0)
+	PHP_ME(DateTimeImmutable, setDate,       arginfo_date_method_date_set, 0)
+	PHP_ME(DateTimeImmutable, setISODate,    arginfo_date_method_isodate_set, 0)
+	PHP_ME(DateTimeImmutable, setTimestamp,  arginfo_date_method_timestamp_set, 0)
+	PHP_FE_END
+};
+
 const zend_function_entry date_funcs_timezone[] = {
 	PHP_ME(DateTimeZone,              __construct,                 arginfo_timezone_open, ZEND_ACC_CTOR|ZEND_ACC_PUBLIC)
 	PHP_ME_MAPPING(getName,           timezone_name_get,           arginfo_timezone_method_name_get, 0)
@@ -508,6 +524,7 @@ PHP_INI_END()
 /* }}} */
 
 zend_class_entry *date_ce_date, *date_ce_timezone, *date_ce_interval, *date_ce_period;
+zend_class_entry *date_ce_immutable;
 
 
 PHPAPI zend_class_entry *php_date_get_date_ce(void)
@@ -515,12 +532,18 @@ PHPAPI zend_class_entry *php_date_get_date_ce(void)
 	return date_ce_date;
 }
 
+PHPAPI zend_class_entry *php_date_get_immutable_ce(void)
+{
+	return date_ce_immutable;
+}
+
 PHPAPI zend_class_entry *php_date_get_timezone_ce(void)
 {
 	return date_ce_timezone;
 }
 
 static zend_object_handlers date_object_handlers_date;
+static zend_object_handlers date_object_handlers_immutable;
 static zend_object_handlers date_object_handlers_timezone;
 static zend_object_handlers date_object_handlers_interval;
 static zend_object_handlers date_object_handlers_period;
@@ -555,11 +578,13 @@ static void date_object_free_storage_interval(void *object TSRMLS_DC);
 static void date_object_free_storage_period(void *object TSRMLS_DC);
 
 static zend_object_value date_object_new_date(zend_class_entry *class_type TSRMLS_DC);
+static zend_object_value date_object_new_immutable(zend_class_entry *class_type TSRMLS_DC);
 static zend_object_value date_object_new_timezone(zend_class_entry *class_type TSRMLS_DC);
 static zend_object_value date_object_new_interval(zend_class_entry *class_type TSRMLS_DC);
 static zend_object_value date_object_new_period(zend_class_entry *class_type TSRMLS_DC);
 
 static zend_object_value date_object_clone_date(zval *this_ptr TSRMLS_DC);
+static zend_object_value date_object_clone_immutable(zval *this_ptr TSRMLS_DC);
 static zend_object_value date_object_clone_timezone(zval *this_ptr TSRMLS_DC);
 static zend_object_value date_object_clone_interval(zval *this_ptr TSRMLS_DC);
 static zend_object_value date_object_clone_period(zval *this_ptr TSRMLS_DC);
@@ -1822,7 +1847,7 @@ static void date_period_it_current_data(zend_object_iterator *iter, zval ***data
 
 	/* Create new object */
 	MAKE_STD_ZVAL(iterator->current);
-	php_date_instantiate(date_ce_date, iterator->current TSRMLS_CC);
+	php_date_instantiate(object->start_ce, iterator->current TSRMLS_CC);
 	newdateobj = (php_date_obj *) zend_object_store_get_object(iterator->current TSRMLS_CC);
 	newdateobj->time = timelib_time_ctor();
 	*newdateobj->time = *it_time;
@@ -1908,7 +1933,7 @@ zend_object_iterator *date_object_period_get_iterator(zend_class_entry *ce, zval
 
 static void date_register_classes(TSRMLS_D)
 {
-	zend_class_entry ce_date, ce_timezone, ce_interval, ce_period;
+	zend_class_entry ce_date, ce_immutable, ce_timezone, ce_interval, ce_period;
 
 	INIT_CLASS_ENTRY(ce_date, "DateTime", date_funcs_date);
 	ce_date.create_object = date_object_new_date;
@@ -1934,6 +1959,13 @@ static void date_register_classes(TSRMLS_D)
 	REGISTER_DATE_CLASS_CONST_STRING("RSS",     DATE_FORMAT_RFC1123);
 	REGISTER_DATE_CLASS_CONST_STRING("W3C",     DATE_FORMAT_RFC3339);
 
+	INIT_CLASS_ENTRY(ce_immutable, "DateTimeImmutable", date_funcs_immutable);
+	ce_immutable.create_object = date_object_new_date;
+	date_ce_immutable = zend_register_internal_class_ex(&ce_immutable, date_ce_date, "DateTime" TSRMLS_CC);
+	memcpy(&date_object_handlers_immutable, zend_get_std_object_handlers(), sizeof(zend_object_handlers));
+	date_object_handlers_immutable.clone_obj = date_object_clone_date;
+	date_object_handlers_immutable.compare_objects = date_object_compare_date;
+	date_object_handlers_immutable.get_properties = date_object_get_properties;
 
 	INIT_CLASS_ENTRY(ce_timezone, "DateTimeZone", date_funcs_timezone);
 	ce_timezone.create_object = date_object_new_timezone;
@@ -2034,6 +2066,19 @@ static zend_object_value date_object_clone_date(zval *this_ptr TSRMLS_DC)
 	return new_ov;
 }
 
+static zval* date_clone_immutable(zval *object)
+{
+	zval *new_object;
+
+	ALLOC_ZVAL(new_object);
+	Z_OBJVAL_P(new_object) = date_object_clone_date(object);
+	Z_SET_REFCOUNT_P(new_object, 1);
+	Z_SET_ISREF_P(new_object);
+	Z_TYPE_P(new_object) = IS_OBJECT;
+
+	return new_object;
+}
+
 static int date_object_compare_date(zval *d1, zval *d2 TSRMLS_DC)
 {
 	if (Z_TYPE_P(d1) == IS_OBJECT && Z_TYPE_P(d2) == IS_OBJECT &&
@@ -2470,6 +2515,26 @@ PHP_FUNCTION(date_create)
 }
 /* }}} */
 
+/* {{{ proto DateTime date_create_immutable([string time[, DateTimeZone object]])
+   Returns new DateTime object
+*/
+PHP_FUNCTION(date_create_immutable)
+{
+	zval           *timezone_object = NULL;
+	char           *time_str = NULL;
+	int             time_str_len = 0;
+
+	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "|sO!", &time_str, &time_str_len, &timezone_object, date_ce_timezone) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	php_date_instantiate(date_ce_immutable, return_value TSRMLS_CC);
+	if (!php_date_initialize(zend_object_store_get_object(return_value TSRMLS_CC), time_str, time_str_len, NULL, timezone_object, 0 TSRMLS_CC)) {
+		RETURN_FALSE;
+	}
+}
+/* }}} */
+
 /* {{{ proto DateTime date_create_from_format(string format, string time[, DateTimeZone object])
    Returns new DateTime object formatted according to the specified format
 */
@@ -2490,6 +2555,26 @@ PHP_FUNCTION(date_create_from_format)
 }
 /* }}} */
 
+/* {{{ proto DateTime date_create_immutable_from_format(string format, string time[, DateTimeZone object])
+   Returns new DateTime object formatted according to the specified format
+*/
+PHP_FUNCTION(date_create_immutable_from_format)
+{
+	zval           *timezone_object = NULL;
+	char           *time_str = NULL, *format_str = NULL;
+	int             time_str_len = 0, format_str_len = 0;
+
+	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "ss|O", &format_str, &format_str_len, &time_str, &time_str_len, &timezone_object, date_ce_timezone) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	php_date_instantiate(date_ce_immutable, return_value TSRMLS_CC);
+	if (!php_date_initialize(zend_object_store_get_object(return_value TSRMLS_CC), time_str, time_str_len, format_str, timezone_object, 0 TSRMLS_CC)) {
+		RETURN_FALSE;
+	}
+}
+/* }}} */
+
 /* {{{ proto DateTime::__construct([string time[, DateTimeZone object]])
    Creates new DateTime object
 */
@@ -2508,6 +2593,24 @@ PHP_METHOD(DateTime, __construct)
 }
 /* }}} */
 
+/* {{{ proto DateTimeImmutable::__construct([string time[, DateTimeZone object]])
+   Creates new DateTimeImmutable object
+*/
+PHP_METHOD(DateTimeImmutable, __construct)
+{
+	zval *timezone_object = NULL;
+	char *time_str = NULL;
+	int time_str_len = 0;
+	zend_error_handling error_handling;
+
+	zend_replace_error_handling(EH_THROW, NULL, &error_handling TSRMLS_CC);
+	if (SUCCESS == zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "|sO!", &time_str, &time_str_len, &timezone_object, date_ce_timezone)) {
+		php_date_initialize(zend_object_store_get_object(getThis() TSRMLS_CC), time_str, time_str_len, NULL, timezone_object, 1 TSRMLS_CC);
+	}
+	zend_restore_error_handling(&error_handling TSRMLS_CC);
+}
+/* }}} */
+
 static int php_date_initialize_from_hash(zval **return_value, php_date_obj **dateobj, HashTable *myht TSRMLS_DC)
 {
 	zval            **z_date = NULL;
@@ -2575,6 +2678,26 @@ PHP_METHOD(DateTime, __set_state)
 }
 /* }}} */
 
+/* {{{ proto DateTimeImmutable::__set_state()
+*/
+PHP_METHOD(DateTimeImmutable, __set_state)
+{
+	php_date_obj     *dateobj;
+	zval             *array;
+	HashTable        *myht;
+
+	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "a", &array) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	myht = HASH_OF(array);
+
+	php_date_instantiate(date_ce_immutable, return_value TSRMLS_CC);
+	dateobj = (php_date_obj *) zend_object_store_get_object(return_value TSRMLS_CC);
+	php_date_initialize_from_hash(&return_value, &dateobj, myht TSRMLS_CC);
+}
+/* }}} */
+
 /* {{{ proto DateTime::__wakeup()
 */
 PHP_METHOD(DateTime, __wakeup)
@@ -2760,21 +2883,12 @@ PHP_FUNCTION(date_format)
 }
 /* }}} */
 
-/* {{{ proto DateTime date_modify(DateTime object, string modify)
-   Alters the timestamp.
-*/
-PHP_FUNCTION(date_modify)
+static void php_date_modify(zval *object, char *modify, int modify_len, zval *return_value TSRMLS_DC)
 {
-	zval         *object;
 	php_date_obj *dateobj;
-	char         *modify;
-	int           modify_len;
 	timelib_time *tmp_time;
 	timelib_error_container *err = NULL;
 
-	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Os", &object, date_ce_date, &modify, &modify_len) == FAILURE) {
-		RETURN_FALSE;
-	}
 	dateobj = (php_date_obj *) zend_object_store_get_object(object TSRMLS_CC);
 	DATE_CHECK_INITIALIZED(dateobj->time, DateTime);
 
@@ -2823,30 +2937,57 @@ PHP_FUNCTION(date_modify)
 	timelib_update_ts(dateobj->time, NULL);
 	timelib_update_from_sse(dateobj->time);
 	dateobj->time->have_relative = 0;
+}
+
+/* {{{ proto DateTime date_modify(DateTime object, string modify)
+   Alters the timestamp.
+*/
+PHP_FUNCTION(date_modify)
+{
+	zval         *object;
+	char         *modify;
+	int           modify_len;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Os", &object, date_ce_date, &modify, &modify_len) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	php_date_modify(object, modify, modify_len, return_value TSRMLS_CC);
 
 	RETURN_ZVAL(object, 1, 0);
 }
 /* }}} */
 
-/* {{{ proto DateTime date_add(DateTime object, DateInterval interval)
-   Adds an interval to the current date in object.
+/* {{{ proto DateTimeImmutable::modify()
 */
-PHP_FUNCTION(date_add)
+PHP_METHOD(DateTimeImmutable, modify)
 {
-	zval         *object, *interval;
-	php_date_obj *dateobj;
+	zval *object, *new_object;
+	char *modify;
+	int   modify_len;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Os", &object, date_ce_date, &modify, &modify_len) == FAILURE) {
+		RETURN_FALSE;
+	}
+	
+	new_object = date_clone_immutable(object);
+	php_date_modify(new_object, modify, modify_len, return_value TSRMLS_CC);
+
+	RETURN_ZVAL(new_object, 0, 1);
+}
+/* }}} */
+
+static void php_date_add(zval *object, zval *interval, zval *return_value TSRMLS_DC)
+{
+	php_date_obj     *dateobj;
 	php_interval_obj *intobj;
 	int               bias = 1;
 
-	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "OO", &object, date_ce_date, &interval, date_ce_interval) == FAILURE) {
-		RETURN_FALSE;
-	}
 	dateobj = (php_date_obj *) zend_object_store_get_object(object TSRMLS_CC);
 	DATE_CHECK_INITIALIZED(dateobj->time, DateTime);
 	intobj = (php_interval_obj *) zend_object_store_get_object(interval TSRMLS_CC);
 	DATE_CHECK_INITIALIZED(intobj->initialized, DateInterval);
 
-
 	if (intobj->diff->have_weekday_relative || intobj->diff->have_special_relative) {
 		memcpy(&dateobj->time->relative, intobj->diff, sizeof(struct timelib_rel_time));
 	} else {
@@ -2867,24 +3008,48 @@ PHP_FUNCTION(date_add)
 	timelib_update_ts(dateobj->time, NULL);
 	timelib_update_from_sse(dateobj->time);
 	dateobj->time->have_relative = 0;
+}
+
+/* {{{ proto DateTime date_add(DateTime object, DateInterval interval)
+   Adds an interval to the current date in object.
+*/
+PHP_FUNCTION(date_add)
+{
+	zval *object, *interval;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "OO", &object, date_ce_date, &interval, date_ce_interval) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	php_date_add(object, interval, return_value TSRMLS_CC);
 
 	RETURN_ZVAL(object, 1, 0);
 }
 /* }}} */
 
-/* {{{ proto DateTime date_sub(DateTime object, DateInterval interval)
-   Subtracts an interval to the current date in object.
+/* {{{ proto DateTimeImmutable::add()
 */
-PHP_FUNCTION(date_sub)
+PHP_METHOD(DateTimeImmutable, add)
 {
-	zval         *object, *interval;
-	php_date_obj *dateobj;
-	php_interval_obj *intobj;
-	int               bias = 1;
+	zval *object, *interval, *new_object;
 
 	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "OO", &object, date_ce_date, &interval, date_ce_interval) == FAILURE) {
 		RETURN_FALSE;
 	}
+
+	new_object = date_clone_immutable(object);
+	php_date_add(new_object, interval, return_value TSRMLS_CC);
+
+	RETURN_ZVAL(new_object, 0, 1);
+}
+/* }}} */
+
+static void php_date_sub(zval *object, zval *interval, zval *return_value TSRMLS_DC)
+{
+	php_date_obj     *dateobj;
+	php_interval_obj *intobj;
+	int               bias = 1;
+
 	dateobj = (php_date_obj *) zend_object_store_get_object(object TSRMLS_CC);
 	DATE_CHECK_INITIALIZED(dateobj->time, DateTime);
 	intobj = (php_interval_obj *) zend_object_store_get_object(interval TSRMLS_CC);
@@ -2913,11 +3078,42 @@ PHP_FUNCTION(date_sub)
 	timelib_update_from_sse(dateobj->time);
 
 	dateobj->time->have_relative = 0;
+}
+
+/* {{{ proto DateTime date_sub(DateTime object, DateInterval interval)
+   Subtracts an interval to the current date in object.
+*/
+PHP_FUNCTION(date_sub)
+{
+	zval *object, *interval;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "OO", &object, date_ce_date, &interval, date_ce_interval) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	php_date_sub(object, interval, return_value TSRMLS_CC);
 
 	RETURN_ZVAL(object, 1, 0);
 }
 /* }}} */
 
+/* {{{ proto DateTimeImmutable::sub()
+*/
+PHP_METHOD(DateTimeImmutable, sub)
+{
+	zval *object, *interval, *new_object;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "OO", &object, date_ce_date, &interval, date_ce_interval) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	new_object = date_clone_immutable(object);
+	php_date_sub(new_object, interval, return_value TSRMLS_CC);
+
+	RETURN_ZVAL(new_object, 0, 1);
+}
+/* }}} */
+
 /* {{{ proto DateTimeZone date_timezone_get(DateTime object)
    Return new DateTimeZone object relative to give DateTime
 */
@@ -2956,19 +3152,11 @@ PHP_FUNCTION(date_timezone_get)
 }
 /* }}} */
 
-/* {{{ proto DateTime date_timezone_set(DateTime object, DateTimeZone object)
-   Sets the timezone for the DateTime object.
-*/
-PHP_FUNCTION(date_timezone_set)
+static void php_date_timezone_set(zval *object, zval *timezone_object, zval *return_value TSRMLS_DC)
 {
-	zval             *object;
-	zval             *timezone_object;
 	php_date_obj     *dateobj;
 	php_timezone_obj *tzobj;
 
-	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "OO", &object, date_ce_date, &timezone_object, date_ce_timezone) == FAILURE) {
-		RETURN_FALSE;
-	}
 	dateobj = (php_date_obj *) zend_object_store_get_object(object TSRMLS_CC);
 	DATE_CHECK_INITIALIZED(dateobj->time, DateTime);
 	tzobj = (php_timezone_obj *) zend_object_store_get_object(timezone_object TSRMLS_CC);
@@ -2978,11 +3166,44 @@ PHP_FUNCTION(date_timezone_set)
 	}
 	timelib_set_timezone(dateobj->time, tzobj->tzi.tz);
 	timelib_unixtime2local(dateobj->time, dateobj->time->sse);
+}
+
+/* {{{ proto DateTime date_timezone_set(DateTime object, DateTimeZone object)
+   Sets the timezone for the DateTime object.
+*/
+PHP_FUNCTION(date_timezone_set)
+{
+	zval *object;
+	zval *timezone_object;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "OO", &object, date_ce_date, &timezone_object, date_ce_timezone) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	php_date_timezone_set(object, timezone_object, return_value TSRMLS_CC);
 
 	RETURN_ZVAL(object, 1, 0);
 }
 /* }}} */
 
+/* {{{ proto DateTimeImmutable::setTimezone()
+*/
+PHP_METHOD(DateTimeImmutable, setTimezone)
+{
+	zval *object, *new_object;
+	zval *timezone_object;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "OO", &object, date_ce_date, &timezone_object, date_ce_timezone) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	new_object = date_clone_immutable(object);
+	php_date_timezone_set(new_object, timezone_object, return_value TSRMLS_CC);
+
+	RETURN_ZVAL(new_object, 0, 1);
+}
+/* }}} */
+
 /* {{{ proto long date_offset_get(DateTime object)
    Returns the DST offset.
 */
@@ -3018,64 +3239,106 @@ PHP_FUNCTION(date_offset_get)
 }
 /* }}} */
 
-/* {{{ proto DateTime date_time_set(DateTime object, long hour, long minute[, long second])
-   Sets the time.
-*/
-PHP_FUNCTION(date_time_set)
+static void php_date_time_set(zval *object, long h, long i, long s, zval *return_value TSRMLS_DC)
 {
-	zval         *object;
 	php_date_obj *dateobj;
-	long          h, i, s = 0;
 
-	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Oll|l", &object, date_ce_date, &h, &i, &s) == FAILURE) {
-		RETURN_FALSE;
-	}
 	dateobj = (php_date_obj *) zend_object_store_get_object(object TSRMLS_CC);
 	DATE_CHECK_INITIALIZED(dateobj->time, DateTime);
 	dateobj->time->h = h;
 	dateobj->time->i = i;
 	dateobj->time->s = s;
 	timelib_update_ts(dateobj->time, NULL);
+}
+
+/* {{{ proto DateTime date_time_set(DateTime object, long hour, long minute[, long second])
+   Sets the time.
+*/
+PHP_FUNCTION(date_time_set)
+{
+	zval *object;
+	long  h, i, s = 0;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Oll|l", &object, date_ce_date, &h, &i, &s) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	php_date_time_set(object, h, i, s, return_value TSRMLS_CC);
 
 	RETURN_ZVAL(object, 1, 0);
 }
 /* }}} */
 
-/* {{{ proto DateTime date_date_set(DateTime object, long year, long month, long day)
-   Sets the date.
+/* {{{ proto DateTimeImmutable::setTime()
 */
-PHP_FUNCTION(date_date_set)
+PHP_METHOD(DateTimeImmutable, setTime)
 {
-	zval         *object;
-	php_date_obj *dateobj;
-	long          y, m, d;
+	zval *object, *new_object;
+	long  h, i, s = 0;
 
-	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Olll", &object, date_ce_date, &y, &m, &d) == FAILURE) {
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Oll|l", &object, date_ce_date, &h, &i, &s) == FAILURE) {
 		RETURN_FALSE;
 	}
+
+	new_object = date_clone_immutable(object);
+	php_date_time_set(new_object, h, i, s, return_value TSRMLS_CC);
+
+	RETURN_ZVAL(new_object, 0, 1);
+}
+/* }}} */
+
+static void php_date_date_set(zval *object, long y, long m, long d, zval *return_value TSRMLS_DC)
+{
+	php_date_obj *dateobj;
+
 	dateobj = (php_date_obj *) zend_object_store_get_object(object TSRMLS_CC);
 	DATE_CHECK_INITIALIZED(dateobj->time, DateTime);
 	dateobj->time->y = y;
 	dateobj->time->m = m;
 	dateobj->time->d = d;
 	timelib_update_ts(dateobj->time, NULL);
+}
+
+/* {{{ proto DateTime date_date_set(DateTime object, long year, long month, long day)
+   Sets the date.
+*/
+PHP_FUNCTION(date_date_set)
+{
+	zval *object;
+	long  y, m, d;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Olll", &object, date_ce_date, &y, &m, &d) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	php_date_date_set(object, y, m, d, return_value TSRMLS_CC);
 
 	RETURN_ZVAL(object, 1, 0);
 }
 /* }}} */
 
-/* {{{ proto DateTime date_isodate_set(DateTime object, long year, long week[, long day])
-   Sets the ISO date.
+/* {{{ proto DateTimeImmutable::setDate()
 */
-PHP_FUNCTION(date_isodate_set)
+PHP_METHOD(DateTimeImmutable, setDate)
 {
-	zval         *object;
-	php_date_obj *dateobj;
-	long          y, w, d = 1;
+	zval *object, *new_object;
+	long  y, m, d;
 
-	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Oll|l", &object, date_ce_date, &y, &w, &d) == FAILURE) {
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Olll", &object, date_ce_date, &y, &m, &d) == FAILURE) {
 		RETURN_FALSE;
 	}
+
+	new_object = date_clone_immutable(object);
+	php_date_date_set(new_object, y, m, d, return_value TSRMLS_CC);
+
+	RETURN_ZVAL(new_object, 0, 1);
+}
+/* }}} */
+
+static void php_date_isodate_set(zval *object, long y, long w, long d, zval *return_value TSRMLS_DC)
+{
+	php_date_obj *dateobj;
+
 	dateobj = (php_date_obj *) zend_object_store_get_object(object TSRMLS_CC);
 	DATE_CHECK_INITIALIZED(dateobj->time, DateTime);
 	dateobj->time->y = y;
@@ -3086,32 +3349,90 @@ PHP_FUNCTION(date_isodate_set)
 	dateobj->time->have_relative = 1;
 	
 	timelib_update_ts(dateobj->time, NULL);
+}
+
+/* {{{ proto DateTime date_isodate_set(DateTime object, long year, long week[, long day])
+   Sets the ISO date.
+*/
+PHP_FUNCTION(date_isodate_set)
+{
+	zval *object;
+	long  y, w, d = 1;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Oll|l", &object, date_ce_date, &y, &w, &d) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	php_date_isodate_set(object, y, w, d, return_value TSRMLS_CC);
 
 	RETURN_ZVAL(object, 1, 0);
 }
 /* }}} */
 
+/* {{{ proto DateTimeImmutable::setISODate()
+*/
+PHP_METHOD(DateTimeImmutable, setISODate)
+{
+	zval *object, *new_object;
+	long  y, w, d = 1;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Oll|l", &object, date_ce_date, &y, &w, &d) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	new_object = date_clone_immutable(object);
+	php_date_isodate_set(new_object, y, w, d, return_value TSRMLS_CC);
+
+	RETURN_ZVAL(new_object, 0, 1);
+}
+/* }}} */
+
+static void php_date_timestamp_set(zval *object, long timestamp, zval *return_value TSRMLS_DC)
+{
+	php_date_obj *dateobj;
+
+	dateobj = (php_date_obj *) zend_object_store_get_object(object TSRMLS_CC);
+	DATE_CHECK_INITIALIZED(dateobj->time, DateTime);
+	timelib_unixtime2local(dateobj->time, (timelib_sll)timestamp);
+	timelib_update_ts(dateobj->time, NULL);
+}
+
 /* {{{ proto DateTime date_timestamp_set(DateTime object, long unixTimestamp)
    Sets the date and time based on an Unix timestamp.
 */
 PHP_FUNCTION(date_timestamp_set)
 {
-	zval         *object;
-	php_date_obj *dateobj;
-	long          timestamp;
+	zval *object;
+	long  timestamp;
 
 	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Ol", &object, date_ce_date, &timestamp) == FAILURE) {
 		RETURN_FALSE;
 	}
-	dateobj = (php_date_obj *) zend_object_store_get_object(object TSRMLS_CC);
-	DATE_CHECK_INITIALIZED(dateobj->time, DateTime);
-	timelib_unixtime2local(dateobj->time, (timelib_sll)timestamp);
-	timelib_update_ts(dateobj->time, NULL);
+
+	php_date_timestamp_set(object, timestamp, return_value TSRMLS_CC);
 
 	RETURN_ZVAL(object, 1, 0);
 }
 /* }}} */
 
+/* {{{ proto DateTimeImmutable::setTimestamp()
+*/
+PHP_METHOD(DateTimeImmutable, setTimestamp)
+{
+	zval *object, *new_object;
+	long  timestamp;
+
+	if (zend_parse_method_parameters(ZEND_NUM_ARGS() TSRMLS_CC, getThis(), "Ol", &object, date_ce_date, &timestamp) == FAILURE) {
+		RETURN_FALSE;
+	}
+
+	new_object = date_clone_immutable(object);
+	php_date_timestamp_set(new_object, timestamp, return_value TSRMLS_CC);
+
+	RETURN_ZVAL(new_object, 0, 1);
+}
+/* }}} */
+
 /* {{{ proto long date_timestamp_get(DateTime object)
    Gets the Unix timestamp.
 */
@@ -3861,6 +4182,7 @@ PHP_METHOD(DatePeriod, __construct)
 		if (dpobj->end) {
 			timelib_update_ts(dpobj->end, NULL);
 		}
+		dpobj->start_ce = date_ce_date;
 	} else {
 		/* init */
 		intobj  = (php_interval_obj *) zend_object_store_get_object(interval TSRMLS_CC);
@@ -3876,6 +4198,7 @@ PHP_METHOD(DatePeriod, __construct)
 			clone->tz_info = dateobj->time->tz_info;
 		}
 		dpobj->start = clone;
+		dpobj->start_ce = Z_OBJCE_P(start);
 
 		/* interval */
 		dpobj->interval = timelib_rel_time_clone(intobj->diff);

ext/date/php_date.h

@@ -51,7 +51,9 @@ PHP_METHOD(DateTime, __construct);
 PHP_METHOD(DateTime, __wakeup);
 PHP_METHOD(DateTime, __set_state);
 PHP_FUNCTION(date_create);
+PHP_FUNCTION(date_create_immutable);
 PHP_FUNCTION(date_create_from_format);
+PHP_FUNCTION(date_create_immutable_from_format);
 PHP_FUNCTION(date_parse);
 PHP_FUNCTION(date_parse_from_format);
 PHP_FUNCTION(date_get_last_errors);
@@ -70,6 +72,17 @@ PHP_FUNCTION(date_isodate_set);
 PHP_FUNCTION(date_timestamp_set);
 PHP_FUNCTION(date_timestamp_get);
 
+PHP_METHOD(DateTimeImmutable, __construct);
+PHP_METHOD(DateTimeImmutable, __set_state);
+PHP_METHOD(DateTimeImmutable, modify);
+PHP_METHOD(DateTimeImmutable, add);
+PHP_METHOD(DateTimeImmutable, sub);
+PHP_METHOD(DateTimeImmutable, setTimezone);
+PHP_METHOD(DateTimeImmutable, setTime);
+PHP_METHOD(DateTimeImmutable, setDate);
+PHP_METHOD(DateTimeImmutable, setISODate);
+PHP_METHOD(DateTimeImmutable, setTimestamp);
+
 PHP_METHOD(DateTimeZone, __construct);
 PHP_FUNCTION(timezone_open);
 PHP_FUNCTION(timezone_name_get);
@@ -141,6 +154,7 @@ struct _php_interval_obj {
 struct _php_period_obj {
 	zend_object       std;
 	timelib_time     *start;
+	zend_class_entry *start_ce;
 	timelib_time     *current;
 	timelib_time     *end;
 	timelib_rel_time *interval;

ext/date/tests/date_period-immutable.phpt

@@ -0,0 +1,56 @@
+--TEST--
+DatePeriod
+--FILE--
+<?php
+date_default_timezone_set('UTC');
+$db1 = new DateTimeImmutable( '2008-01-01' );
+$db2 = new DateTime( '2008-01-01' );
+$de = new DateTime( '2008-03-31' );
+$di = DateInterval::createFromDateString( 'first day of next month' );
+
+foreach ( new DatePeriod( $db1, $di, $de ) as $dt )
+{
+	echo get_class( $dt ), "\n";
+	echo $dt->format( "l Y-m-d\n" );
+    echo $dt->modify( "3 tuesday" )->format( "l Y-m-d\n" );
+	echo $dt->format( "l Y-m-d\n\n" );
+}
+
+foreach ( new DatePeriod( $db2, $di, $de ) as $dt )
+{
+	echo get_class( $dt ), "\n";
+	echo $dt->format( "l Y-m-d\n" );
+    echo $dt->modify( "3 tuesday" )->format( "l Y-m-d\n" );
+	echo $dt->format( "l Y-m-d\n\n" );
+}
+?>
+--EXPECT--
+DateTimeImmutable
+Tuesday 2008-01-01
+Tuesday 2008-01-15
+Tuesday 2008-01-01
+
+DateTimeImmutable
+Friday 2008-02-01
+Tuesday 2008-02-19
+Friday 2008-02-01
+
+DateTimeImmutable
+Saturday 2008-03-01
+Tuesday 2008-03-18
+Saturday 2008-03-01
+
+DateTime
+Tuesday 2008-01-01
+Tuesday 2008-01-15
+Tuesday 2008-01-15
+
+DateTime
+Friday 2008-02-01
+Tuesday 2008-02-19
+Tuesday 2008-02-19
+
+DateTime
+Saturday 2008-03-01
+Tuesday 2008-03-18
+Tuesday 2008-03-18

ext/date/tests/date_time_immutable-inherited.phpt

@@ -0,0 +1,25 @@
+--TEST--
+Tests for DateTimeImmutable.
+--INI--
+date.timezone=Europe/London
+--FILE--
+<?php
+$tz = new DateTimeZone("Asia/Tokyo");
+$current = "2012-12-27 16:24:08";
+
+echo "\ngetTimezone():\n";
+$v = date_create_immutable($current);
+$x = $v->getTimezone();
+var_dump($x->getName());
+
+echo "\ngetTimestamp():\n";
+$v = date_create_immutable($current);
+$x = $v->getTimestamp();
+var_dump($x);
+?>
+--EXPECT--
+getTimezone():
+string(13) "Europe/London"
+
+getTimestamp():
+int(1356625448)

ext/date/tests/date_time_immutable.phpt

@@ -0,0 +1,167 @@
+--TEST--
+Tests for DateTimeImmutable.
+--INI--
+date.timezone=Europe/London
+--FILE--
+<?php
+$tz = new DateTimeZone("Asia/Tokyo");
+$current = "2012-12-27 16:24:08";
+
+function dump($a, $b, $c)
+{
+	echo 'orig:    ', $a->format('Y-m-d H:i:s e'), "\n";
+	echo 'copy:    ', $b->format('Y-m-d H:i:s e'), "\n";
+	echo 'changed: ', $c->format('Y-m-d H:i:s e'), "\n";
+}
+
+echo "modify():\n";
+$v = date_create_immutable($current);
+$z = $v;
+$x = $z->modify("+2 days");
+dump($v, $z, $x);
+$v = date_create($current);
+$z = $v;
+$x = $z->modify("+2 days");
+dump($v, $z, $x);
+
+echo "\nadd():\n";
+$v = date_create_immutable($current);
+$z = $v;
+$x = $z->add(new DateInterval("P2DT2S"));
+dump($v, $z, $x);
+$v = date_create($current);
+$z = $v;
+$x = $z->add(new DateInterval("P2DT2S"));
+dump($v, $z, $x);
+
+echo "\nsub():\n";
+$v = date_create_immutable($current);
+$z = $v;
+$x = $z->sub(new DateInterval("P2DT2S"));
+dump($v, $z, $x);
+$v = date_create($current);
+$z = $v;
+$x = $z->sub(new DateInterval("P2DT2S"));
+dump($v, $z, $x);
+
+echo "\nsetTimezone():\n";
+$v = date_create_immutable($current);
+$z = $v;
+$x = $z->setTimezone($tz);
+dump($v, $z, $x);
+$v = date_create($current);
+$z = $v;
+$x = $z->setTimezone($tz);
+dump($v, $z, $x);
+$v = new DateTimeImmutable($current);
+$z = $v;
+$x = $z->setTimezone($tz);
+dump($v, $z, $x);
+
+echo "\nsetTime():\n";
+$v = date_create_immutable($current);
+$z = $v;
+$x = $z->setTime(5, 7, 19);
+dump($v, $z, $x);
+$v = date_create($current);
+$z = $v;
+$x = $z->setTime(5, 7, 19);
+dump($v, $z, $x);
+
+echo "\nsetDate():\n";
+$v = date_create_immutable($current);
+$z = $v;
+$x = $z->setDate(5, 7, 19);
+dump($v, $z, $x);
+$v = date_create($current);
+$z = $v;
+$x = $z->setDate(5, 7, 19);
+dump($v, $z, $x);
+
+echo "\nsetIsoDate():\n";
+$v = date_create_immutable($current);
+$z = $v;
+$x = $z->setIsoDate(2012, 2, 6);
+dump($v, $z, $x);
+$v = date_create($current);
+$z = $v;
+$x = $z->setIsoDate(2012, 2, 6);
+dump($v, $z, $x);
+
+echo "\nsetTimestamp():\n";
+$v = date_create_immutable($current);
+$z = $v;
+$x = $z->setTimestamp(2012234222);
+dump($v, $z, $x);
+$v = date_create($current);
+$z = $v;
+$x = $z->setTimestamp(2012234222);
+dump($v, $z, $x);
+?>
+--EXPECT--
+modify():
+orig:    2012-12-27 16:24:08 Europe/London
+copy:    2012-12-27 16:24:08 Europe/London
+changed: 2012-12-29 16:24:08 Europe/London
+orig:    2012-12-29 16:24:08 Europe/London
+copy:    2012-12-29 16:24:08 Europe/London
+changed: 2012-12-29 16:24:08 Europe/London
+
+add():
+orig:    2012-12-27 16:24:08 Europe/London
+copy:    2012-12-27 16:24:08 Europe/London
+changed: 2012-12-29 16:24:10 Europe/London
+orig:    2012-12-29 16:24:10 Europe/London
+copy:    2012-12-29 16:24:10 Europe/London
+changed: 2012-12-29 16:24:10 Europe/London
+
+sub():
+orig:    2012-12-27 16:24:08 Europe/London
+copy:    2012-12-27 16:24:08 Europe/London
+changed: 2012-12-25 16:24:06 Europe/London
+orig:    2012-12-25 16:24:06 Europe/London
+copy:    2012-12-25 16:24:06 Europe/London
+changed: 2012-12-25 16:24:06 Europe/London
+
+setTimezone():
+orig:    2012-12-27 16:24:08 Europe/London
+copy:    2012-12-27 16:24:08 Europe/London
+changed: 2012-12-28 01:24:08 Asia/Tokyo
+orig:    2012-12-28 01:24:08 Asia/Tokyo
+copy:    2012-12-28 01:24:08 Asia/Tokyo
+changed: 2012-12-28 01:24:08 Asia/Tokyo
+orig:    2012-12-27 16:24:08 Europe/London
+copy:    2012-12-27 16:24:08 Europe/London
+changed: 2012-12-28 01:24:08 Asia/Tokyo
+
+setTime():
+orig:    2012-12-27 16:24:08 Europe/London
+copy:    2012-12-27 16:24:08 Europe/London
+changed: 2012-12-27 05:07:19 Europe/London
+orig:    2012-12-27 05:07:19 Europe/London
+copy:    2012-12-27 05:07:19 Europe/London
+changed: 2012-12-27 05:07:19 Europe/London
+
+setDate():
+orig:    2012-12-27 16:24:08 Europe/London
+copy:    2012-12-27 16:24:08 Europe/London
+changed: 0005-07-19 16:24:08 Europe/London
+orig:    0005-07-19 16:24:08 Europe/London
+copy:    0005-07-19 16:24:08 Europe/London
+changed: 0005-07-19 16:24:08 Europe/London
+
+setIsoDate():
+orig:    2012-12-27 16:24:08 Europe/London
+copy:    2012-12-27 16:24:08 Europe/London
+changed: 2012-01-14 16:24:08 Europe/London
+orig:    2012-01-14 16:24:08 Europe/London
+copy:    2012-01-14 16:24:08 Europe/London
+changed: 2012-01-14 16:24:08 Europe/London
+
+setTimestamp():
+orig:    2012-12-27 16:24:08 Europe/London
+copy:    2012-12-27 16:24:08 Europe/London
+changed: 2033-10-06 18:57:02 Europe/London
+orig:    2033-10-06 18:57:02 Europe/London
+copy:    2033-10-06 18:57:02 Europe/London
+changed: 2033-10-06 18:57:02 Europe/London