Struct HeaderNode 

pub struct HeaderNode {
    pub tsn: Tsn,
    pub free_lists_tree_root_id: PageID,
    pub events_tree_root_id: PageID,
    pub tags_tree_root_id: PageID,
    pub next_page_id: PageID,
    pub next_position: Position,
    pub schema_version: u32,
    pub tracking_root_page_id: PageID,
}

Fields

tsn: Tsn

free_lists_tree_root_id: PageID

events_tree_root_id: PageID

tags_tree_root_id: PageID

next_page_id: PageID

next_position: Position

schema_version: u32

On-disk schema version for the header node

tracking_root_page_id: PageID

Implementations

impl HeaderNode

pub fn calc_serialized_size(&self) -> usize

Writes the serialized HeaderNode into the provided buffer and returns the number of bytes written (52). The buffer must be at least 52 bytes long.

pub fn serialize_into(&self, buf: &mut [u8]) -> DcbResult<usize>

pub fn from_slice(slice: &[u8]) -> DcbResult<Self>

Deserializes a HeaderNode from a byte slice.

This function is strictly backward-compatible. It accepts legacy 48-byte layouts and dynamically defaults newer fields to 0 or empty if the provided slice is shorter than the current schema.

Byte Layout

Core Header (Required - 48 bytes):

• 00..08: tsn (u64)
• 08..16: next_page_id (u64)
• 16..24: free_lists_tree_root_id (u64)
• 24..32: events_tree_root_id (u64)
• 32..40: tags_tree_root_id (u64)
• 40..48: next_position (u64)

Extensions (Optional):

• 48..52: schema_version (u32, defaults to 0)
• 52..54: flags (u16, defaults to empty)
• 54..62: tracking_root_page_id (u64, parsed only if HAS_TRACKING_ROOT_ID flag is set, defaults to 0)

Arguments

• slice - The byte slice containing the serialized header data.

Errors

Returns a DcbError::DeserializationError if:

• The slice is smaller than the core 48 bytes.
• Unrecognized bits are set in the flags field.
• The HAS_TRACKING_ROOT_ID flag is present, but the slice is too short to contain the 8-byte ID.

Trait Implementations

impl Clone for HeaderNode

fn clone(&self) -> HeaderNode

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for HeaderNode

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

Formats the value using the given formatter.

impl Default for HeaderNode

fn default() -> Self

Returns the “default value” for a type.

impl Eq for HeaderNode

impl PartialEq for HeaderNode

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for HeaderNode