wasm_dbms_memory/
memory_access.rs

1// Rust guideline compliant 2026-03-01
2// X-WHERE-CLAUSE, M-CANONICAL-DOCS
3
4//! Trait abstracting page-level memory operations.
5//!
6//! [`MemoryAccess`] is the primary interface consumed by registry and
7//! ledger code in this crate. [`MemoryManager`](crate::MemoryManager)
8//! implements it with direct writes; the DBMS crate provides a
9//! journaled wrapper that records original bytes before each write.
10
11use wasm_dbms_api::prelude::{Encode, MemoryResult, Page, PageOffset};
12
13/// Abstraction over page-level memory operations.
14///
15/// All table-registry and ledger functions are generic over this trait
16/// so that callers can transparently add write-ahead journaling or
17/// other interceptors without modifying the memory crate.
18pub trait MemoryAccess {
19    /// Returns the size of a single memory page.
20    fn page_size(&self) -> u64;
21
22    /// Allocates an additional page in memory and returns its number.
23    fn allocate_page(&mut self) -> MemoryResult<Page>;
24
25    /// Reads a typed value from the specified page and offset.
26    fn read_at<D>(&self, page: Page, offset: PageOffset) -> MemoryResult<D>
27    where
28        D: Encode;
29
30    /// Writes a typed value at the specified page and offset.
31    fn write_at<E>(&mut self, page: Page, offset: PageOffset, data: &E) -> MemoryResult<()>
32    where
33        E: Encode;
34
35    /// Zeros out the region occupied by `data` at the specified page
36    /// and offset.
37    fn zero<E>(&mut self, page: Page, offset: PageOffset, data: &E) -> MemoryResult<()>
38    where
39        E: Encode;
40
41    /// Reads raw bytes into `buf` at the specified page and offset.
42    ///
43    /// Returns the number of bytes actually read.
44    fn read_at_raw(&self, page: Page, offset: PageOffset, buf: &mut [u8]) -> MemoryResult<usize>;
45}
wasm_dbms_memory/memory_access.rs

wasm_dbms_memory/
memory_access.rs
