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Request processing of two major processes in PHP kernel_PHP tutorial
- WBOYOriginal
- 2016-07-13 10:13:32810browse
Request processing of two major processes in PHP core
static int php_handler(request_rec *r)
{
/* Initiliaze the context */
php_struct * volatile ctx;
void *conf;
apr_bucket_brigade * volatile brigade;
apr_bucket *bucket;
apr_status_t rv;
request_rec * volatile parent_req = NULL;
TSRMLS_FETCH();
......
zend_file_handle zfd;
zfd.type = ZEND_HANDLE_FILENAME;
zfd.filename = (char *) r->filename;
zfd.free_filename = 0;
zfd.opened_path = NULL;
zend_execute_scripts(ZEND_INCLUDE TSRMLS_CC, NULL, 1, &zfd);
......
}
ZEND_API int zend_execute_scripts(int type TSRMLS_DC, zval **retval, int file_count, ...) /* {{{ */
{
......
EG(active_op_array) = \
zend_compile_file(file_handle, type TSRMLS_CC);
......
zend_execute(EG(active_op_array) TSRMLS_CC);
......
}
ZEND_API void execute(zend_op_array *op_array TSRMLS_DC)  
{  
    // 初始化执行上下文  
    zend_execute_data execute_data;  
  
    // 如果有异常就退出执行  
    if (EG(exception)) {  
        return;  
    }  
  
    /* Initialize execute_data */  
    EX(fbc) = NULL; // 初始化正在调用的函数  
    EX(object) = NULL; // 初始化正在调用的对象  
    EX(old_error_reporting) = NULL; // 初始化错误报告变量  
      
    // 为执行栈分配空间  
    if (op_array->T < TEMP_VAR_STACK_LIMIT) {  
        EX(Ts) = (temp_variable *) do_alloca(sizeof(temp_variable) * op_array->T);  
    } else {  
        EX(Ts) = (temp_variable *) safe_emalloc(sizeof(temp_variable), op_array->T, 0);  
    }  
    // 为临时变量分配空间并初始化这些空间  
    EX(CVs) = (zval***)do_alloca(sizeof(zval**) * op_array->last_var);  
    memset(EX(CVs), 0, sizeof(zval**) * op_array->last_var);  
      
    EX(op_array) = op_array;  
      
    // 切换执行上下文  
    EX(original_in_execution) = EG(in_execution);  
    EX(symbol_table) = EG(active_symbol_table);  
    EX(prev_execute_data) = EG(current_execute_data); // 将当前全局变量中的执行数据压栈  
    EG(current_execute_data) = &execute_data; // 将当前执行上下文压栈  
  
    EG(in_execution) = 1;  
    // 初始化第一个指令(opcode)  
    /* 
    #define ZEND_VM_SET_OPCODE(new_op) \ 
    CHECK_SYMBOL_TABLES() \ 
    EX(opline) = new_op 
     
    execute_data.opline 为当前执行的 opcode 
    */  
    if (op_array->start_op) {  
        ZEND_VM_SET_OPCODE(op_array->start_op);  
    } else {  
        ZEND_VM_SET_OPCODE(op_array->opcodes);  
    }  
  
    if (op_array->uses_this && EG(This)) {  
        EG(This)->refcount++; /* For $this pointer */  
        if (zend_hash_add(EG(active_symbol_table), "this", sizeof("this"), &EG(This), sizeof(zval *), NULL)==FAILURE) {  
            EG(This)->refcount--;  
        }  
    }  
  
    // 将存储opline的内存地址赋给 executor_globals.online_ptr ，可以实时跟踪opcode的执行  
    EG(opline_ptr) = &EX(opline);  
  
    EX(function_state).function = (zend_function *) op_array;  
    EG(function_state_ptr) = &EX(function_state);  
#if ZEND_DEBUG  
    /* function_state.function_symbol_table is saved as-is to a stack, 
     * which is an intentional UMR.  Shut it up if we're in DEBUG. 
     */  
    EX(function_state).function_symbol_table = NULL;  
#endif  
      
    while (1) {  
#ifdef ZEND_WIN32  
        if (EG(timed_out)) {  
            zend_timeout(0);  
        }  
#endif  
          
        // 循环调用每个opline的 handler 函数，如果是推出函数的话，返回值大于0，就退出  
        if (EX(opline)->handler(&execute_data TSRMLS_CC) > 0) {  
      return;  
        }  
  
    }  
    zend_error_noreturn(E_ERROR, "Arrived at end of main loop which shouldn't happen");  
}  Statement：
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