PHP源码分析之变量的存储过程分解

$php_var = 1; 

zval c_var;    //定义PHP变量指针 
MAKE_STD_ZVAL(c_var);  //初始化PHP变量 
ZVAL_LONG(c_var,1) ;//赋值 
ZEND_SET_SYMBL( EG(active_symbol_table), " php_var ", c_var);//注册到全局变量符号表

struct _zval_struct { 
    / Variable information / 
    zvalue_value value;     / 变量的值 / 
    zend_uint refcount;     / 引用计数,垃圾回收的时候用到 / 
    zend_uchar type;        / 变量类型 / 
    zend_uchar is_ref;      / 是否为引用变量 / 
}; 
typedef struct _zval_struct zval; 

typedef union _zvalue_value { 
    long lval;              / 长整形/ 
    double dval;            / 双精度类型 / 
    struct {                  / 字符串类型的值 / 
        char val;             
        int len; 
    } str; 
    HashTable ht;              / 数组类型的值 / 
    zend_object_value obj;     /对象类型的值/ 
} zvalue_value; 

#define MAKE_STD_ZVAL(zv)                \ 
    ALLOC_ZVAL(zv); \ 
    INIT_PZVAL(zv); 
 
#define ALLOC_ZVAL(z)   \ 
    ZEND_FAST_ALLOC(z, zval, ZVAL_CACHE_LIST) 
 
#define ZEND_FAST_ALLOC(p, type, fc_type)   \ 
    (p) = (type ) emalloc(sizeof(type)) 
 
#define INIT_PZVAL(z)       \ 
    (z)->refcount = 1;      \ 
    (z)->is_ref = 0; 

(c_var) = (zval ) emalloc(sizeof(zval));  //分配内存 
(c_var)-> refcount = 1;  //引用计数初始化 
(c_var)-> is_ref = 0; //是否引用 

//定义值 
#define ZVAL_LONG(z, l) {           \ 
     Z_TYPE_P(z) = IS_LONG;      \ 
     Z_LVAL_P(z) = l;            \ 
} 
#define Z_TYPE_P(zval_p)    Z_TYPE(zval_p) 
#define Z_TYPE(zval)        (zval).type 
#define Z_LVAL_P(zval_p)    Z_LVAL(zval_p) 
#define Z_LVAL(zval)            (zval).value.lval 

( c_var).type = IS_LONG; 
( c_var).value = 1; 

struct _zend_executor_globals {   
        …. 
        HashTable symbol_table;//全局变量的符号表   
        HashTable active_symbol_table;//局部变量的符号表   
        ….. 
    };   

#define ZEND_SET_SYMBOL(symtable, name, var)          \   {                                                     \ 
        char _name = (name);                         \ 
        ZEND_SET_SYMBOL_WITH_LENGTH(symtable, _name, strlen(_name)+1, var, 1, 0);   \ 
} 
//主要的实现为狼蚁网站SEO优化这个函数 
#define ZEND_SET_SYMBOL_WITH_LENGTH(symtable, name, name_length, var, _refcount, _is_ref)                                                       \ 
    {                                                                        
        zval orig_var;                                        \  
        if (zend_hash_find(symtable, (name), (name_length), (void ) &orig_var)==SUCCESS                                                         \ 
            && PZVAL_IS_REF(orig_var)) {                     \ 
            (var)->refcount = (orig_var)->refcount;                  \ 
            (var)->is_ref = 1;                                \ 
            if (_refcount) {                                      \ 
                (var)->refcount += _refcount-1;               \ 
            }                                             \ 
            zval_dtor(orig_var);                             \ 
            orig_var = (var);                                  \ 
            FREE_ZVAL(var);                               \ 
        } else {                                              \ 
            (var)->is_ref = _is_ref;                              \ 
            if (_refcount) {                                      \ 
                (var)->refcount = _refcount;                      \ 
            }                                             \ 
            zend_hash_update(symtable, (name), (name_length), &(var), sizeof(zval ), NULL);                                                           \ 
        }                                                  \ 
    }