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WitnessKey

Enum WitnessKey 

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pub enum WitnessKey {
    Page(PageNumber),
    Cell {
        btree_root: PageNumber,
        leaf_page: PageNumber,
        tag: u64,
    },
    ByteRange {
        page: PageNumber,
        start: u32,
        len: u32,
    },
    KeyRange {
        btree_root: PageNumber,
        lo: Vec<u8>,
        hi: Vec<u8>,
    },
    Custom {
        namespace: u32,
        bytes: Vec<u8>,
    },
}
Expand description

SSI witness key basis (§5.6.4.3).

Canonical key space for SSI rw-antidependency tracking. Always valid to fall back to Page(pgno) — finer keys reduce false positives but never compromise correctness.

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Page(PageNumber)

Coarse witness: entire page.

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Cell

Semantic witness: specific B-tree cell identified by domain-separated hash.

tag is low32(xxh3_64("fsqlite:witness:cell:v1" || le_u32(btree_root) || key_bytes)).

Fields

§btree_root: PageNumber
§leaf_page: PageNumber
§tag: u64
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ByteRange

Semantic witness: structured byte range on a page.

Fields

§start: u32
§len: u32
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KeyRange

Key range witness for reduced false positives on range scans (optional, advanced).

Fields

§btree_root: PageNumber
§lo: Vec<u8>
§hi: Vec<u8>
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Custom

Custom namespace witness (extensibility point).

Fields

§namespace: u32
§bytes: Vec<u8>

Implementations§

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impl WitnessKey

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pub fn cell_tag(btree_root: PageNumber, canonical_key_bytes: &[u8]) -> u64

Derive a deterministic cell tag from a B-tree root page and canonical key bytes.

Uses domain-separated xxh3_64 (§5.6.4.3): cell_tag = low32(xxh3_64("fsqlite:witness:cell:v1" || le_u32(btree_root_pgno) || key_bytes))

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pub fn for_cell_read( btree_root: PageNumber, leaf_page: PageNumber, canonical_key_bytes: &[u8], ) -> Self

Create a cell witness for a point read/uniqueness check.

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pub fn for_range_scan(leaf_pages: &[PageNumber]) -> Vec<Self>

Create page-level witnesses for a range scan (phantom protection).

Returns one Page(leaf_pgno) witness per visited leaf page (§5.6.4.3).

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pub fn for_point_write( btree_root: PageNumber, canonical_key_bytes: &[u8], leaf_pgno: PageNumber, ) -> (Self, Self)

Create a cell + page witness pair for a point write.

Writes register both Cell(btree_root, leaf_page, cell_tag) AND Page(leaf_pgno) as write witnesses (§5.6.4.3).

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pub const fn page_number(&self) -> Option<PageNumber>

Return the page-like bucket associated with this witness.

Page and byte-range witnesses map to their physical page. Cell and key-range witnesses are bucketed by their B-tree root page so higher layers can retain O(1) page/root-level witness indexes. Custom witnesses are intentionally left unbucketed.

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pub fn is_page(&self) -> bool

Returns true if this is a coarse page-level witness.

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pub fn is_cell(&self) -> bool

Returns true if this is a cell-level semantic witness.

Trait Implementations§

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impl Clone for WitnessKey

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fn clone(&self) -> WitnessKey

Returns a duplicate of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for WitnessKey

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

Formats the value using the given formatter. Read more
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impl<'de> Deserialize<'de> for WitnessKey

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fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>
where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer. Read more
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impl Hash for WitnessKey

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl Ord for WitnessKey

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fn cmp(&self, other: &WitnessKey) -> Ordering

This method returns an Ordering between self and other. Read more
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fn max(self, other: Self) -> Self
where Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Self
where Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · Source§

fn clamp(self, min: Self, max: Self) -> Self
where Self: Sized,

Restrict a value to a certain interval. Read more
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impl PartialEq for WitnessKey

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

Tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialOrd for WitnessKey

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fn partial_cmp(&self, other: &WitnessKey) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl Serialize for WitnessKey

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fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>
where __S: Serializer,

Serialize this value into the given Serde serializer. Read more
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impl Eq for WitnessKey

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impl StructuralPartialEq for WitnessKey

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impl<T> Any for T
where T: 'static + ?Sized,

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Gets the TypeId of self. Read more
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unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (clone_to_uninit)
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Instruments this future with a span (no-op when disabled).
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