mirror of
https://github.com/php/php-src.git
synced 2024-12-13 03:44:17 +08:00
196 lines
7.1 KiB
Plaintext
196 lines
7.1 KiB
Plaintext
Creating an object
|
|
------------------
|
|
|
|
Object can be created in the following ways:
|
|
|
|
1. As a result of a function call. E.g.:
|
|
|
|
$foo = create_new_foo("parameter");
|
|
$foo->run();
|
|
|
|
The function should create a new zval, create new object and get the
|
|
handle for it, set handle and handler table as needed. Note that the
|
|
handle is the only ID of the object, so it should be enough to
|
|
identify it.
|
|
|
|
2. Overriding create_object handler for class. E.g.:
|
|
|
|
$foo = new Java("some.Class.here", "parameter");
|
|
$foo->run();
|
|
|
|
The create_object handler function should create a new zval, create
|
|
new object and get the handle for it, set handle and handler table as
|
|
needed, and also provide constructor method that would handle
|
|
constructor call. The get_constructor handler table entry should be
|
|
used for that. Do not rely class entry's constructor, unless you refer
|
|
to it from get_constructor handler.
|
|
|
|
Object maintenance
|
|
------------------
|
|
|
|
The handlers add_ref and del_ref are called when a new zval referring
|
|
to the object is created. This does not create a new object - both
|
|
zvals still refer to the same object.
|
|
|
|
clone_obj handler should create a new object, identical to an old one,
|
|
but being a separate entity.
|
|
|
|
delete_obj should destroy an object, all references to it become
|
|
invalid.
|
|
|
|
Object access - read
|
|
--------------------
|
|
|
|
read_property is used to read object's property. This value is not
|
|
meant to be changed. The handler returns zval * with the value.
|
|
|
|
Object access - write
|
|
---------------------
|
|
|
|
write_property is used to directly write object's property by
|
|
name. This handler is used to assign property variables or to change them
|
|
in operations like += or ++ (unless get_property_zval_ptr is also set).
|
|
|
|
get_property_zval_ptr is used to obtain pointer to modifiable zval for
|
|
operations like += or ++. This should be used only if your object model
|
|
stores properties as real zval's that can be modified from outside.
|
|
Otherwise this handler should be NULL and the engine will use
|
|
read_property and write_property instead.
|
|
|
|
get_property_ptr is used to obtain zval ** for future writing to
|
|
it. If your object properties are stored as zval*, return real place
|
|
where the property is stored. If the aren't, the best way is to create
|
|
proxy object and handle it via get and set methods (see below).
|
|
This method is meant to be used for send-by-reference and assign-by-reference
|
|
use of object properties. If you don;t want to implement property
|
|
referencing for your objects, you can set this handler to NULL.
|
|
|
|
get and set handlers are used when engine needs to access the object
|
|
as a value. E.g., in the following situation:
|
|
|
|
$foo =& $obj->bar;
|
|
$foo = 1;
|
|
|
|
if $foo is an object (e.g., proxy object from get_property_ptr) it
|
|
would be accessed using write handler.
|
|
|
|
Object access - method call
|
|
---------------------------
|
|
|
|
get_method handler is used to find method description by name. It
|
|
should set right type, function name and parameter mask for the
|
|
method. If the type is ZEND_OVERLOADED_FUNCTION, the method would be
|
|
called via call_method handler, otherwise it would be called with
|
|
standard Zend means.
|
|
|
|
get_constructor performs the same function as get_method, but for the
|
|
object constructor.
|
|
|
|
call_method handler is used to perform method call. Parameters are
|
|
passed like to any other Zend internal function.
|
|
|
|
Object - comparison
|
|
-------------------
|
|
|
|
Objects can be compared via compare_objects handler. This is used with
|
|
== operation, === compares objects by handles, i.e., return true if
|
|
and only if it's really the same object. Note that objects from
|
|
different object types (i.e., having different handlers) can not be
|
|
compared.
|
|
|
|
Objects - reflection
|
|
--------------------
|
|
|
|
get_class_name is used to retrieve class name of the object.
|
|
get_class_entry returns class entry (zend_class_entry) for the object,
|
|
in case there exists PHP class for it.
|
|
No other reflection functions are currently implemented.
|
|
|
|
Objects - data structures and handlers
|
|
---------------------------------------
|
|
|
|
The object is represented by the following structure:
|
|
|
|
struct _zend_object_value {
|
|
zend_object_handle handle;
|
|
zend_object_handlers *handlers;
|
|
};
|
|
|
|
handle is an ID of the object among the objects of the same type (not
|
|
class!). The type of the object and how it behaves is determined by
|
|
the handler table.
|
|
|
|
typedef struct _zend_object_handlers {
|
|
zend_object_add_ref_t add_ref;
|
|
zend_object_del_ref_t del_ref;
|
|
zend_object_delete_obj_t delete_obj;
|
|
zend_object_clone_obj_t clone_obj;
|
|
zend_object_read_property_t read_property;
|
|
zend_object_write_property_t write_property;
|
|
zend_object_get_property_ptr_t get_property_ptr;
|
|
zend_object_get_property_zval_ptr_t get_property_zval_ptr;
|
|
zend_object_get_t get;
|
|
zend_object_set_t set;
|
|
zend_object_has_property_t has_property;
|
|
zend_object_unset_property_t unset_property;
|
|
zend_object_get_properties_t get_properties;
|
|
zend_object_get_method_t get_method;
|
|
zend_object_call_method_t call_method;
|
|
zend_object_get_constructor_t get_constructor;
|
|
zend_object_get_class_entry_t get_class_entry;
|
|
zend_object_get_class_name_t get_class_name;
|
|
zend_object_compare_t compare_objects;
|
|
} zend_object_handlers;
|
|
|
|
See zend_object_handlers.h for prototypes. All objects are passed as zval's.
|
|
|
|
Handlers explained:
|
|
|
|
add_ref - called when a copy of the object handle is created.
|
|
|
|
del_ref - called when a copy of the object handle is destroyed.
|
|
|
|
delete_obj - called when an object needs to be destroyed.
|
|
|
|
clone_obj - called when a new object identical to an old one should be
|
|
created (unlike Zend Engine 1, this never happens unless explicitly
|
|
asked for).
|
|
|
|
read_property - returns zval *, containing the value of the
|
|
property. Is used when value of the property should be retrieved for
|
|
reading.
|
|
|
|
write_property - assigns value to certain property of the object.
|
|
|
|
get_property_zval_ptr - retrieves zval** for being directly modified by
|
|
the engine. If your properties are not zval's, don't define it.
|
|
|
|
get_property_ptr - retrieves zval** for the property of the value, to
|
|
be used for read and write. If object properties are not zval's
|
|
natively, this method should create and return proxy object for use
|
|
with get and set methods.
|
|
|
|
get - retrieves zval* for object contents. To be used mainly with
|
|
proxy objects from get_property_ptr, but also may be used for
|
|
convert_to_* functions.
|
|
|
|
set - sets value for object contents. To be used mainly with
|
|
proxy objects from get_property_ptr.
|
|
|
|
has_property - checks if the object has certain property set.
|
|
|
|
unset_property - removes value for the property of the object
|
|
|
|
get_method - retrieves description of the method
|
|
|
|
call_method - calls the method (parameters should be put on stack like
|
|
for any other PHP internal function).
|
|
|
|
get_constructor - get description for the object constructor method
|
|
|
|
get_class_entry - should return the class entry for the object
|
|
|
|
get_class_name - get the name of the class the object belongs to
|
|
|
|
compare_objects - compares if two objects are equal
|