include|require(_once)? 在php底层实现

ZEND_VM_HANDLER(73, ZEND_INCLUDE_OR_EVAL, CONST|TMP|VAR|CV, ANY)
{
	USE_OPLINE
	zend_op_array *new_op_array=NULL;
	zend_free_op free_op1;
	zval *inc_filename;
	zval *tmp_inc_filename = NULL;
	zend_bool failure_retval=0;

	SAVE_OPLINE();
	inc_filename = GET_OP1_ZVAL_PTR(BP_VAR_R);

	if (inc_filename->type!=IS_STRING) {
		MAKE_STD_ZVAL(tmp_inc_filename);
		ZVAL_COPY_VALUE(tmp_inc_filename, inc_filename);
		zval_copy_ctor(tmp_inc_filename);
		convert_to_string(tmp_inc_filename);
		inc_filename = tmp_inc_filename;
	}

	if (opline->extended_value != ZEND_EVAL && strlen(Z_STRVAL_P(inc_filename)) != Z_STRLEN_P(inc_filename)) {
		if (opline->extended_value == ZEND_INCLUDE_ONCE || opline->extended_value == ZEND_INCLUDE) {
			zend_message_dispatcher(ZMSG_FAILED_INCLUDE_FOPEN, Z_STRVAL_P(inc_filename) TSRMLS_CC);
		} else {
			zend_message_dispatcher(ZMSG_FAILED_REQUIRE_FOPEN, Z_STRVAL_P(inc_filename) TSRMLS_CC);
		}
	} else {
		switch (opline->extended_value) {
			case ZEND_INCLUDE_ONCE:
			case ZEND_REQUIRE_ONCE: {
					zend_file_handle file_handle;
					char *resolved_path;

					resolved_path = zend_resolve_path(Z_STRVAL_P(inc_filename), Z_STRLEN_P(inc_filename) TSRMLS_CC);
					if (resolved_path) {
						failure_retval = zend_hash_exists(&EG(included_files), resolved_path, strlen(resolved_path)+1);
					} else {
						resolved_path = Z_STRVAL_P(inc_filename);
					}

					if (failure_retval) {
						/* do nothing, file already included */
					} else if (SUCCESS == zend_stream_open(resolved_path, &file_handle TSRMLS_CC)) {

						if (!file_handle.opened_path) {
							file_handle.opened_path = estrdup(resolved_path);
						}

						if (zend_hash_add_empty_element(&EG(included_files), file_handle.opened_path, strlen(file_handle.opened_path)+1)==SUCCESS) {
							new_op_array = zend_compile_file(&file_handle, (opline->extended_value==ZEND_INCLUDE_ONCE?ZEND_INCLUDE:ZEND_REQUIRE) TSRMLS_CC);
							zend_destroy_file_handle(&file_handle TSRMLS_CC);
						} else {
							zend_file_handle_dtor(&file_handle TSRMLS_CC);
							failure_retval=1;
						}
					} else {
						if (opline->extended_value == ZEND_INCLUDE_ONCE) {
							zend_message_dispatcher(ZMSG_FAILED_INCLUDE_FOPEN, Z_STRVAL_P(inc_filename) TSRMLS_CC);
						} else {
							zend_message_dispatcher(ZMSG_FAILED_REQUIRE_FOPEN, Z_STRVAL_P(inc_filename) TSRMLS_CC);
						}
					}
					if (resolved_path != Z_STRVAL_P(inc_filename)) {
						efree(resolved_path);
					}
				}
				break;
			case ZEND_INCLUDE:
			case ZEND_REQUIRE:
				new_op_array = compile_filename(opline->extended_value, inc_filename TSRMLS_CC);
				break;
			case ZEND_EVAL: {
					char *eval_desc = zend_make_compiled_string_description("eval()'d code" TSRMLS_CC);

					new_op_array = zend_compile_string(inc_filename, eval_desc TSRMLS_CC);
					efree(eval_desc);
				}
				break;
			EMPTY_SWITCH_DEFAULT_CASE()
		}
	}
	if (tmp_inc_filename) {
		zval_ptr_dtor(&tmp_inc_filename);
	}
	FREE_OP1();
	if (UNEXPECTED(EG(exception) != NULL)) {
		HANDLE_EXCEPTION();
	} else if (EXPECTED(new_op_array != NULL)) {
		EX(original_return_value) = EG(return_value_ptr_ptr);
		EG(active_op_array) = new_op_array;
		if (RETURN_VALUE_USED(opline)) {
			EX_T(opline->result.var).var.ptr = NULL;
			EX_T(opline->result.var).var.ptr_ptr = &EX_T(opline->result.var).var.ptr;
			EG(return_value_ptr_ptr) = EX_T(opline->result.var).var.ptr_ptr;
		} else {
			EG(return_value_ptr_ptr) = NULL;
		}

		EX(function_state).function = (zend_function *) new_op_array;
		EX(object) = NULL;

		if (!EG(active_symbol_table)) {
			zend_rebuild_symbol_table(TSRMLS_C);
		}

		if (EXPECTED(zend_execute_ex == execute_ex)) {
			ZEND_VM_ENTER();
		} else {
			zend_execute(new_op_array TSRMLS_CC);
		}

		EX(function_state).function = (zend_function *) EX(op_array);

		EG(opline_ptr) = &EX(opline);
		EG(active_op_array) = EX(op_array);
		EG(return_value_ptr_ptr) = EX(original_return_value);
		destroy_op_array(new_op_array TSRMLS_CC);
		efree(new_op_array);
		if (UNEXPECTED(EG(exception) != NULL)) {
			zend_throw_exception_internal(NULL TSRMLS_CC);
			HANDLE_EXCEPTION();
		}

	} else if (RETURN_VALUE_USED(opline)) {
		zval *retval;

		ALLOC_ZVAL(retval);
		ZVAL_BOOL(retval, failure_retval);
		INIT_PZVAL(retval);
		AI_SET_PTR(&EX_T(opline->result.var), retval);
	}
	ZEND_VM_NEXT_OPCODE();
}

总结两点：

1、include(_once)和require(_once)底层实现就一点区别，zend_message_dispatcher函数指针分发的报错信息参数不一，这个参数决定了在包含文件找不到的时候是否还能执行之后的代码。

2、include|require直接执行compile_filename，带once的需要获取文件真实路劲、检查include_files符号表是、如果不存在打开文件、文件路径添加到include_files符号表，最后执行zend_compile_file。