深入PHP内核之面向对象总结

很久以前看过的，今天总结一下

一、PHP中创建一个类

在PHP中创建一个简单的类是这样的：

<?php
$obj = new test($url)
?>

二、zend_class_entry结构

zend_class_entry是内核中定义的一个结构体，是PHP中类与对象的基础结构类型。

struct _zend_class_entry {
char type;     // 类型：ZEND_INTERNAL_CLASS / ZEND_USER_CLASS
char *name;// 类名称
zend_uint name_length;                  // 即sizeof(name) - 1
struct　_zend_class_entry *parent; // 继承的父类
int　refcount;  // 引用数
zend_bool constants_updated;

zend_uint ce_flags; // ZEND_ACC_IMPLICIT_ABSTRACT_CLASS: 类存在abstract方法
// ZEND_ACC_EXPLICIT_ABSTRACT_CLASS: 在类名称前加了abstract关键字
// ZEND_ACC_FINAL_CLASS
// ZEND_ACC_INTERFACE
HashTable function_table;      // 方法
HashTable default_properties;          // 默认属性
HashTable properties_info;     // 属性信息
HashTable default_static_members;// 类本身所具有的静态变量
HashTable *static_members; // type == ZEND_USER_CLASS时，取&default_static_members;
// type == ZEND_INTERAL_CLASS时，设为NULL
HashTable constants_table;     // 常量
struct _zend_function_entry *builtin_functions;// 方法定义入口

union _zend_function *constructor;
union _zend_function *destructor;
union _zend_function *clone;

/* 魔术方法 */
union _zend_function *__get;
union _zend_function *__set;
union _zend_function *__unset;
union _zend_function *__isset;
union _zend_function *__call;
union _zend_function *__tostring;
union _zend_function *serialize_func;
union _zend_function *unserialize_func;
zend_class_iterator_funcs iterator_funcs;// 迭代

/* 类句柄 */
zend_object_value (*create_object)(zend_class_entry *class_type TSRMLS_DC);
zend_object_iterator *(*get_iterator)(zend_class_entry *ce, zval *object,
intby_ref TSRMLS_DC);

/* 类声明的接口 */
int(*interface_gets_implemented)(zend_class_entry *iface,
zend_class_entry *class_type TSRMLS_DC);

/* 序列化回调函数指针 */
int(*serialize)(zval *object， unsignedchar**buffer, zend_uint *buf_len,
zend_serialize_data *data TSRMLS_DC);
int(*unserialize)(zval **object, zend_class_entry *ce, constunsignedchar*buf,
zend_uint buf_len, zend_unserialize_data *data TSRMLS_DC);

zend_class_entry **interfaces;  //  类实现的接口
zend_uint num_interfaces;   //  类实现的接口数

char *filename; //  类的存放文件地址 绝对地址
zend_uint line_start;   //  类定义的开始行
zend_uint line_end; //  类定义的结束行
char *doc_comment;
zend_uint doc_comment_len;

struct _zend_module_entry *module; // 类所在的模块入口：EG(current_module)
};

二、访问控制

//fn_flags代表可以在定义方法时使用，zend_property_info.flags代表可以在定义属性时使用，ce_flags代表在定义zend_class_entry时候可用
//ZEND_ACC_CTOR 构造函数掩码 , ZEND_ACC_DTOR  析构函数掩码
//ZEND_ACC_STATIC static函数掩码
//ZEND_ACC_ABSTRACT abstract函数掩码

#define ZEND_ACC_STATIC                     0x01     /* fn_flags, zend_property_info.flags */
#define ZEND_ACC_ABSTRACT                   0x02     /* fn_flags */
#define ZEND_ACC_FINAL                      0x04     /* fn_flags */
#define ZEND_ACC_IMPLEMENTED_ABSTRACT       0x08     /* fn_flags */
#define ZEND_ACC_IMPLICIT_ABSTRACT_CLASS    0x10     /* ce_flags */
#define ZEND_ACC_EXPLICIT_ABSTRACT_CLASS    0x20     /* ce_flags */
#define ZEND_ACC_FINAL_CLASS                0x40     /* ce_flags */
#define ZEND_ACC_INTERFACE                  0x80     /* ce_flags */
#define ZEND_ACC_INTERACTIVE                0x10     /* fn_flags */
#define ZEND_ACC_PUBLIC                     0x100    /* fn_flags, zend_property_info.flags */
#define ZEND_ACC_PROTECTED                  0x200    /* fn_flags, zend_property_info.flags */
#define ZEND_ACC_PRIVATE                    0x400    /* fn_flags, zend_property_info.flags */
#define ZEND_ACC_PPP_MASK   (ZEND_ACC_PUBLIC | ZEND_ACC_PROTECTED | ZEND_ACC_PRIVATE)
#define ZEND_ACC_CHANGED                    0x800    /* fn_flags, zend_property_info.flags */
#define ZEND_ACC_IMPLICIT_PUBLIC            0x1000   /* zend_property_info.flags; unused (1) */
#define ZEND_ACC_CTOR                       0x2000   /* fn_flags */
#define ZEND_ACC_DTOR                       0x4000   /* fn_flags */
#define ZEND_ACC_CLONE                      0x8000   /* fn_flags */
#define ZEND_ACC_ALLOW_STATIC               0x10000  /* fn_flags */
#define ZEND_ACC_SHADOW                     0x20000  /* fn_flags */
#define ZEND_ACC_DEPRECATED                 0x40000  /* fn_flags */
#define ZEND_ACC_CLOSURE                    0x100000 /* fn_flags */
#define ZEND_ACC_CALL_VIA_HANDLER           0x200000 /* fn_flags */

三、申明和更新类中的属性

ZEND_API int zend_declare_class_constant(zend_class_entry *ce, const char *name, size_t name_length, zval *value TSRMLS_DC);
ZEND_API int zend_declare_class_constant_null(zend_class_entry *ce, const char *name, size_t name_length TSRMLS_DC);
ZEND_API int zend_declare_class_constant_long(zend_class_entry *ce, const char *name, size_t name_length, long value TSRMLS_DC);
ZEND_API int zend_declare_class_constant_bool(zend_class_entry *ce, const char *name, size_t name_length, zend_bool value TSRMLS_DC);
ZEND_API int zend_declare_class_constant_double(zend_class_entry *ce, const char *name, size_t name_length, double value TSRMLS_DC);
ZEND_API int zend_declare_class_constant_stringl(zend_class_entry *ce, const char *name, size_t name_length, const char *value, size_t value_length TSRMLS_DC);
ZEND_API int zend_declare_class_constant_string(zend_class_entry *ce, const char *name, size_t name_length, const char *value TSRMLS_DC);

ZEND_API void zend_update_property_null(zend_class_entry *scope, zval *object, char *name, int name_length TSRMLS_DC);
ZEND_API void zend_update_property_bool(zend_class_entry *scope, zval *object, char *name, int name_length, long value TSRMLS_DC);
ZEND_API void zend_update_property_long(zend_class_entry *scope, zval *object, char *name, int name_length, long value TSRMLS_DC);
ZEND_API void zend_update_property_double(zend_class_entry *scope, zval *object, char *name, int name_length, double value TSRMLS_DC);
ZEND_API void zend_update_property_string(zend_class_entry *scope, zval *object, char *name, int name_length, const char *value TSRMLS_DC);
ZEND_API void zend_update_property_stringl(zend_class_entry *scope, zval *object, char *name, int name_length, const char *value, int value_length TSRMLS_DC);

ZEND_API int zend_update_static_property_null(zend_class_entry *scope, char *name, int name_length TSRMLS_DC);
ZEND_API int zend_update_static_property_bool(zend_class_entry *scope, char *name, int name_length, long value TSRMLS_DC);
ZEND_API int zend_update_static_property_long(zend_class_entry *scope, char *name, int name_length, long value TSRMLS_DC);
ZEND_API int zend_update_static_property_double(zend_class_entry *scope, char *name, int name_length, double value TSRMLS_DC);
ZEND_API int zend_update_static_property_string(zend_class_entry *scope, char *name, int name_length, const char *value TSRMLS_DC);
ZEND_API int zend_update_static_property_stringl(zend_class_entry *scope, char *name, int name_length, const char *value, int value_length TSRMLS_DC);

动态添加属性

#define add_property_long(__arg, __key, __n) add_property_long_ex(__arg, __key, strlen(__key)+1, __n TSRMLS_CC)
#define add_property_null(__arg, __key) add_property_null_ex(__arg, __key, strlen(__key) + 1 TSRMLS_CC)
#define add_property_bool(__arg, __key, __b) add_property_bool_ex(__arg, __key, strlen(__key)+1, __b TSRMLS_CC)
#define add_property_resource(__arg, __key, __r) add_property_resource_ex(__arg, __key, strlen(__key)+1, __r TSRMLS_CC)
#define add_property_double(__arg, __key, __d) add_property_double_ex(__arg, __key, strlen(__key)+1, __d TSRMLS_CC)
#define add_property_string(__arg, __key, __str, __duplicate) add_property_string_ex(__arg, __key, strlen(__key)+1, __str, __duplicate TSRMLS_CC)
#define add_property_stringl(__arg, __key, __str, __length, __duplicate) add_property_stringl_ex(__arg, __key, strlen(__key)+1, __str, __length, __duplicate TSRMLS_CC)
#define add_property_zval(__arg, __key, __value) add_property_zval_ex(__arg, __key, strlen(__key)+1, __value TSRMLS_CC)

四、一些其它的宏

#define INIT_CLASS_ENTRY(class_container, class_name, functions) INIT_OVERLOADED_CLASS_ENTRY(class_container, class_name, functions, NULL, NULL, NULL)

#define INIT_OVERLOADED_CLASS_ENTRY(class_container, class_name, functions, handle_fcall, handle_propget, handle_propset)  INIT_OVERLOADED_CLASS_ENTRY_EX(class_container, class_name, sizeof(class_name)-1, functions, handle_fcall, handle_propget, handle_propset, NULL, NULL)

define INIT_CLASS_ENTRY_EX(class_container, class_name, class_name_len, functions) INIT_OVERLOADED_CLASS_ENTRY_EX(class_container, class_name, class_name_len, functions, NULL, NULL, NULL, NULL, NULL)

define INIT_OVERLOADED_CLASS_ENTRY_EX(class_container, class_name, class_name_len, functions, handle_fcall, handle_propget, handle_propset, handle_propunset, handle_propisset) {
const char *cl_name = class_name;
int _len = class_name_len;
class_container.name = zend_new_interned_string(cl_name, _len+1, 0 TSRMLS_CC);
if (class_container.name == cl_name) {
class_container.name = zend_strndup(cl_name, _len);
}
class_container.name_length = _len;
INIT_CLASS_ENTRY_INIT_METHODS(class_container, functions, handle_fcall, handle_propget, handle_propset, handle_propunset, handle_propisset) \
}

#define INIT_CLASS_ENTRY_INIT_METHODS(class_container, functions, handle_fcall, handle_propget, handle_propset, handle_propunset, handle_propisset) {
class_container.constructor = NULL;
class_container.destructor = NULL;
class_container.clone = NULL;
class_container.serialize = NULL;
class_container.unserialize = NULL;
class_container.create_object = NULL;
class_container.interface_gets_implemented = NULL;
class_container.get_static_method = NULL;
class_container.__call = handle_fcall;
class_container.__callstatic = NULL;
class_container.__tostring = NULL;
class_container.__get = handle_propget;
class_container.__set = handle_propset;
class_container.__unset = handle_propunset;
class_container.__isset = handle_propisset;
class_container.serialize_func = NULL;
class_container.unserialize_func = NULL;
class_container.serialize = NULL;
class_container.unserialize = NULL;
class_container.parent = NULL;
class_container.num_interfaces = 0;
class_container.traits = NULL;
class_container.num_traits = 0;
class_container.trait_aliases = NULL;
class_container.trait_precedences = NULL;
class_container.interfaces = NULL;
class_container.get_iterator = NULL;
class_container.iterator_funcs.funcs = NULL;
class_container.info.internal.module = NULL;
class_container.info.internal.builtin_functions = functions;
}

五、PHP_METHOD

PHP_METHOD(test,__construct);
PHP_METHOD(test,__destruct);
PHP_METHOD(test,setproperty);
PHP_METHOD(test,getproperty);

内核中的定义

#define PHP_METHOD  ZEND_METHOD
#define ZEND_METHOD(classname, name)   ZEND_NAMED_FUNCTION(ZEND_MN(classname##_##name))
#define INTERNAL_FUNCTION_PARAMETERS int ht, zval *return_value, zval **return_value_ptr, zval *this_ptr, int return_v    alue_used TSRMLS_DC

//等价于
void name(int ht, zval *return_value, zval **return_value_ptr, zval *this_ptr, int return_v    alue_used TSRMLS_DC )

六、zend_arg_info

typedef struct _zend_arg_info {
const char *name; //参数名称
zend_uint name_len;//长度
const char *class_name;  //所属类名
zend_uint class_name_len;  //类名长度
zend_bool array_type_hint;
zend_bool allow_null; //允许为空
zend_bool pass_by_reference;  //引用传值
zend_bool return_reference;   //引用返回
int required_num_args;   //参数个数
} zend_arg_info;

接受参数.那么就要执行　

ZEND_BEGIN_ARG_INFO(test___construct_arginfo, 0)
ZEND_ARG_INFO(0, url)
ZEND_END_ARG_INFO()

ZEND_BEGIN_ARG_INFO_EX定义在Zend/zend_API.h

define ZEND_BEGIN_ARG_INFO_EX(name, pass_rest_by_reference, return_reference, required_num_args)       \
static const zend_arg_info name[] = {                                                                                                                                           \
{ NULL, 0, NULL, 0, 0, 0, pass_rest_by_reference, return_reference, required_num_args },

ZEND_ARG_INFO(0,url)的定义如下

#define ZEND_ARG_INFO(pass_by_ref, name) { #name, sizeof(#name)-1, NULL, 0, 0, 0, pass_by_ref, 0, 0 },

最终是这样的

static const zend_arg_info name[] = {
{ NULL, 0, NULL, 0, 0, 0, pass_rest_by_reference, return_reference, required_num_args },
{ #name, sizeof(#name)-1, NULL, 0, 0, 0, pass_by_ref, 0, 0 },
};

七、定义一个类

1、申明

static zend_class_entry *test_ce;

2、添加方法

const zend_function_entry test_methods[] = {
PHP_ME(test, __construct, test___construct_arginfo, ZEND_ACC_PUBLIC | ZEND_ACC_CTOR)
PHP_ME(test, __destruct, NULL, ZEND_ACC_PUBLIC | ZEND_ACC_DTOR)
PHP_ME(test, __toString, NULL, ZEND_ACC_PUBLIC)
PHP_ME(test, getMeta, NULL, ZEND_ACC_PUBLIC)
PHP_ME(test, setMeta, NULL, ZEND_ACC_PUBLIC)
{ NULL, NULL, NULL }
};

//ZEND_ACC_CTOR标示构造函数
//ZEND_ACC_DTOR标示析构函数

3、PHP_MINIT_FUNCTION中初始化

PHP_MINIT_FUNCTION(test)
{
/*定义一个temp class*/
zend_class_entry ce;

/*初始化这个class，第二个参数是class name, 第三个参数是class methods*/
INIT_CLASS_ENTRY(ce, "test", test_methods);

/*注册这个class到zend engine*/
test_ce = zend_register_internal_class(&ce TSRMLS_CC);

return SUCCESS;
}

4、定义参数

ZEND_BEGIN_ARG_INFO(test___construct_arginfo, 0)
ZEND_ARG_INFO(0, url)
ZEND_END_ARG_INFO()

5、具体方法

static PHP_METHOD(test, __construct) {
char *url;
int url_len;

if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "s", &url, &url_len, &age) == FAILURE) {
return;
}

zval *obj;
obj = getThis();

zend_update_property_stringl(test_ce, obj, "url", sizeof("url") -1, url, url_len TSRMLS_CC);
}

6、在PHP中访问

<?php
$c = new test('http://test.com');
?>

可以参考的文章
http://www.phpinternalsbook.com/classes_objects/simple_classes.html