Struct JsonMeta 

pub struct JsonMeta {
    pub base: KeyMeta,
    pub format: JsonStorageFormat,
}

Structure metadata. JSON 结构元数据（对标 Apache Kvrocks JsonMetadata 27 字节/26 字节）

Fields

base: KeyMeta

format: JsonStorageFormat

Implementations

impl JsonMeta

pub const ENCODED_SIZE: usize

pub const KVROCKS_ENCODED_SIZE: usize

pub fn new(expire_at: u64, version: u64, size: u64) -> Self

pub fn new_with_version(expire_at: u64, size: u64) -> Self

pub fn with_format( format: JsonStorageFormat, expire_at: u64, version: u64, size: u64, ) -> Self

pub fn is_expired(&self, now_ms: u64) -> bool

pub fn encode(&self) -> [u8; 27]

Encodes data into binary format. 编码为标准 27 字节 wedb 元数据头（栈上定长数组，零堆分配）

pub fn encode_kvrocks(&self) -> [u8; 10]

Encodes data into binary format. 编码为 Kvrocks 10 字节紧凑元数据头（栈上定长数组，零堆分配，对标 Kvrocks JsonMetadata）

pub fn decode(bytes: &[u8]) -> Option<(Self, &[u8])>

Decodes data from binary format. 解码元数据头与载荷切片（支持 27 字节 wedb 标准头与 10 字节 Kvrocks 头）

Methods from Deref<Target = KeyMeta>

pub const META_64BIT_ENCODING_MASK: u8 = 0x80

pub const META_TYPE_MASK: u8 = 0x0F

pub const ENCODED_SIZE: usize = 26

pub const KVROCKS_COMPLEX_ENCODED_SIZE: usize = 25

pub const KVROCKS_SINGLE_KV_ENCODED_SIZE: usize = 9

pub fn is_expired(&self, now_ms: u64) -> bool

pub fn is_single_kv_type(&self) -> bool

pub fn is_emptyable_type(&self) -> bool

pub fn ttl(&self, now_ms: u64) -> i64

pub fn ttl_ms(&self, now_ms: u64) -> i64

pub fn ttl_sec(&self, now_ms: u64) -> i64

pub fn is_64bit_encoded(&self) -> bool

pub fn common_encoded_size(&self) -> usize

pub fn encode(&self) -> [u8; 26]

Encodes into standard 26-byte metadata header. 编码为标准 26 字节元数据头

pub fn encode_kvrocks(&self) -> Vec<u8>

Encodes into compact Kvrocks binary format (25-byte composite / 9-byte SingleKV). 编码为 Kvrocks 1:1 紧凑二进制格式（25字节复合类型 / 9字节SingleKV）

Trait Implementations

impl Clone for JsonMeta

fn clone(&self) -> JsonMeta

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for JsonMeta

impl Debug for JsonMeta

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'__de> Decode<'__de> for JsonMeta

where '__de:,

impl Deref for JsonMeta

type Target = KeyMeta

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl DerefMut for JsonMeta

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl Encode for JsonMeta

impl Eq for JsonMeta

impl MetaOps for JsonMeta

const TAG: &[u8]

Metadata key tag slice (e.g. b"sm", b"hm"). meta key 标签（如 b"sm", b"hm"），用于 check_key_not_other_type

type EncodedBytes = [u8; 27]

fn decode(bytes: &[u8]) -> Option<Self>

fn is_expired(&self, now_ms: u64) -> bool

fn encode_bytes(&self) -> Self::EncodedBytes

Encoded bytes slice for storage write operations without heap allocation. 编码后的字节，用于写入存储（零堆分配）

fn base(&self) -> &KeyMeta

Returns immutable reference to base KeyMeta. 获取 base 引用（访问 expire_at / ttl 等通用字段）

fn base_mut(&mut self) -> &mut KeyMeta

Returns mutable reference to base KeyMeta. 获取 base 可变引用（修改 expire_at）

impl PartialEq for JsonMeta

fn eq(&self, other: &JsonMeta) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for JsonMeta