PHP资源的实现和操作

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typedef struct _zend_rsrc_list_entry
{
    void *ptr;
    int type;
    int refcount;
}zend_rsrc_list_entry;

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// 资源名称
#define PHP_DONIE_RES_NAME_FILE "Donie's File Descriptor"

// 资源类型
static int le_donie_file_descriptor;
static int le_donie_file_descriptor_persist;

// 资源析构函数
static void php_donie_file_descriptor_dtor(zend_rsrc_list_entry *rsrc TSRMLS_CC)
{
	FILE *fp = (FILE*)rsrc->ptr;
	fclose(fp);
}

// 在扩展的MINIT方法里创建资源类型
PHP_MINIT_FUNCTION(donie)
{
	/* create a new resource type */
	le_donie_file_descriptor = zend_register_list_destructors_ex(
		php_donie_file_descriptor_dtor, NULL, PHP_DONIE_RES_NAME_FILE, module_number
	);

	/* create a persistent resource type */
	le_donie_file_descriptor_persist = zend_register_list_destructors_ex(
		NULL, php_donie_file_descriptor_dtor, PHP_DONIE_RES_NAME_FILE, module_number
	);

	return SUCCESS;
}

// 文件打开操作
PHP_FUNCTION(donie_fopen)
{
	FILE *fp;
	char *filename, *mode;
	int filename_len, mode_len;
	zend_bool persist = 0;
	char *hash_key;
	int hash_key_len;
	list_entry *persist_file;

	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "ss|b", &filename, &filename_len, &mode, &mode_len, &persist) == FAILURE)
	{
		RETURN_NULL();
	}
	if (!filename_len || !mode_len)
	{
		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Invalid file name or mode.");
		RETURN_FALSE;
	}

	/* reuse persistent resource if exists */
	hash_key_len = spprintf(&hash_key, 0, "php_donie_file_descriptor:%s-%s", filename, mode);
	if (zend_hash_find(&EG(persistent_list), hash_key, hash_key_len+1, (void **)&persist_file) == SUCCESS)
	{
		ZEND_REGISTER_RESOURCE(return_value, persist_file->ptr, le_donie_file_descriptor_persist);
		efree(hash_key);
		return;
	}

	fp = fopen(filename, mode);
	if (!fp)
	{
		php_error_docref(NULL TSRMLS_CC, E_WARNING, "Failed opening %s with mode %s.", filename, mode);
		RETURN_FALSE;
	}

	/* this is the key point for registering resources */
	if (persist)
	{
		ZEND_REGISTER_RESOURCE(return_value, fp, le_donie_file_descriptor_persist);
		list_entry le;
		le.type = le_donie_file_descriptor_persist;
		le.ptr = fp;
		zend_hash_update(&EG(persistent_list), hash_key, hash_key_len+1, (void*)&le, sizeof(list_entry), NULL);
	}
	else
	{
		ZEND_REGISTER_RESOURCE(return_value, fp, le_donie_file_descriptor);
	}
	efree(hash_key);
}

// 文件写操作
PHP_FUNCTION(donie_fwrite)
{
	FILE *fp;
	zval *file_resource;
	char *data;
	int data_len;

	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "rs", &file_resource, &data, &data_len) == FAILURE)
	{
		RETURN_NULL();
	}

	ZEND_FETCH_RESOURCE2(fp, FILE*, &file_resource, -1, PHP_DONIE_RES_NAME_FILE, le_donie_file_descriptor, le_donie_file_descriptor_persist);
	RETURN_LONG(fwrite(data, 1, data_len, fp));
}

// 文件关闭操作
PHP_FUNCTION(donie_fclose)
{
	FILE *fp;
	zval *file_resource;

	if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "r", &file_resource) == FAILURE)
	{
		RETURN_NULL();
	}

	ZEND_FETCH_RESOURCE2(fp, FILE*, &file_resource, -1, PHP_DONIE_RES_NAME_FILE, le_donie_file_descriptor, le_donie_file_descriptor_persist);
	zend_hash_index_del(&EG(regular_list), Z_RESVAL_P(file_resource));
	RETURN_TRUE;
}

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<?php
$a = donie_fopen('/tmp/donie.txt', 'r');
$b = $a;
$c = &$a;
?>

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char *hash_key;
int hash_key_len;
zend_rsrc_list_entry le;
le.type = le_donie_file_descriptor_persist;
le.ptr = fp;
hash_key_len = spprintf(&hash_key, 0, "php_donie_file_descriptor:%s-%s", filename, mode);
zend_hash_update(&EG(persistent_list), hash_key, hash_key_len+1, (void*)&le, sizeof(list_entry), NULL);