Files
turso/core/storage/header_accessor.rs
2025-07-24 11:29:01 +04:00

231 lines
9.3 KiB
Rust

use crate::storage::sqlite3_ondisk::MAX_PAGE_SIZE;
use crate::turso_assert;
use crate::{
storage::{
self,
pager::{PageRef, Pager},
sqlite3_ondisk::DATABASE_HEADER_PAGE_ID,
},
types::IOResult,
LimboError, Result,
};
// const HEADER_OFFSET_MAGIC: usize = 0;
const HEADER_OFFSET_PAGE_SIZE: usize = 16;
const HEADER_OFFSET_WRITE_VERSION: usize = 18;
const HEADER_OFFSET_READ_VERSION: usize = 19;
const HEADER_OFFSET_RESERVED_SPACE: usize = 20;
const HEADER_OFFSET_MAX_EMBED_FRAC: usize = 21;
const HEADER_OFFSET_MIN_EMBED_FRAC: usize = 22;
const HEADER_OFFSET_MIN_LEAF_FRAC: usize = 23;
const HEADER_OFFSET_CHANGE_COUNTER: usize = 24;
const HEADER_OFFSET_DATABASE_SIZE: usize = 28;
const HEADER_OFFSET_FREELIST_TRUNK_PAGE: usize = 32;
const HEADER_OFFSET_FREELIST_PAGES: usize = 36;
const HEADER_OFFSET_SCHEMA_COOKIE: usize = 40;
const HEADER_OFFSET_SCHEMA_FORMAT: usize = 44;
const HEADER_OFFSET_DEFAULT_PAGE_CACHE_SIZE: usize = 48;
const HEADER_OFFSET_VACUUM_MODE_LARGEST_ROOT_PAGE: usize = 52;
const HEADER_OFFSET_TEXT_ENCODING: usize = 56;
const HEADER_OFFSET_USER_VERSION: usize = 60;
const HEADER_OFFSET_INCREMENTAL_VACUUM_ENABLED: usize = 64;
const HEADER_OFFSET_APPLICATION_ID: usize = 68;
//const HEADER_OFFSET_RESERVED_FOR_EXPANSION: usize = 72;
const HEADER_OFFSET_VERSION_VALID_FOR: usize = 92;
const HEADER_OFFSET_VERSION_NUMBER: usize = 96;
// Helper to get a read-only reference to the header page.
fn get_header_page(pager: &Pager) -> Result<IOResult<PageRef>> {
if !pager.db_state.is_initialized() {
return Err(LimboError::InternalError(
"Database is empty, header does not exist - page 1 should've been allocated before this".to_string(),
));
}
let page = pager.read_page(DATABASE_HEADER_PAGE_ID)?;
if page.is_locked() {
return Ok(IOResult::IO);
}
Ok(IOResult::Done(page))
}
// Helper to get a writable reference to the header page and mark it dirty.
fn get_header_page_for_write(pager: &Pager) -> Result<IOResult<PageRef>> {
if !pager.db_state.is_initialized() {
// This should not be called on an empty DB for writing, as page 1 is allocated on first transaction.
return Err(LimboError::InternalError(
"Cannot write to header of an empty database - page 1 should've been allocated before this".to_string(),
));
}
let page = pager.read_page(DATABASE_HEADER_PAGE_ID)?;
if page.is_locked() {
return Ok(IOResult::IO);
}
turso_assert!(
page.get().id == DATABASE_HEADER_PAGE_ID,
"page must have number 1"
);
pager.add_dirty(&page);
Ok(IOResult::Done(page))
}
/// Helper function to run async header accessors until completion
fn run_header_accessor_until_done<T, F>(pager: &Pager, mut accessor: F) -> Result<T>
where
F: FnMut() -> Result<IOResult<T>>,
{
loop {
match accessor()? {
IOResult::Done(value) => return Ok(value),
IOResult::IO => {
pager.io.run_once()?;
}
}
}
}
/// Helper macro to implement getters and setters for header fields.
/// For example, `impl_header_field_accessor!(page_size, u16, HEADER_OFFSET_PAGE_SIZE);`
/// will generate the following functions:
/// - `pub fn get_page_size(pager: &Pager) -> Result<u16>` (sync)
/// - `pub fn get_page_size_async(pager: &Pager) -> Result<CursorResult<u16>>` (async)
/// - `pub fn set_page_size(pager: &Pager, value: u16) -> Result<()>` (sync)
/// - `pub fn set_page_size_async(pager: &Pager, value: u16) -> Result<CursorResult<()>>` (async)
///
/// The macro takes three required arguments:
/// - `$field_name`: The name of the field to implement.
/// - `$type`: The type of the field.
/// - `$offset`: The offset of the field in the header page.
///
/// And a fourth optional argument:
/// - `$ifzero`: A value to return if the field is 0.
///
/// The macro will generate both sync and async versions of the functions.
///
macro_rules! impl_header_field_accessor {
($field_name:ident, $type:ty, $offset:expr $(, $ifzero:expr)?) => {
paste::paste! {
// Async version
#[allow(dead_code)]
pub fn [<get_ $field_name _async>](pager: &Pager) -> Result<IOResult<$type>> {
if !pager.db_state.is_initialized() {
return Err(LimboError::InternalError(format!("Database is empty, header does not exist - page 1 should've been allocated before this")));
}
let page = match get_header_page(pager)? {
IOResult::Done(page) => page,
IOResult::IO => return Ok(IOResult::IO),
};
let page_inner = page.get();
let page_content = page_inner.contents.as_ref().unwrap();
let buf = page_content.buffer.borrow();
let buf_slice = buf.as_slice();
let mut bytes = [0; std::mem::size_of::<$type>()];
bytes.copy_from_slice(&buf_slice[$offset..$offset + std::mem::size_of::<$type>()]);
let value = <$type>::from_be_bytes(bytes);
$(
if value == 0 {
return Ok(IOResult::Done($ifzero));
}
)?
Ok(IOResult::Done(value))
}
// Sync version
#[allow(dead_code)]
pub fn [<get_ $field_name>](pager: &Pager) -> Result<$type> {
run_header_accessor_until_done(pager, || [<get_ $field_name _async>](pager))
}
// Async setter
#[allow(dead_code)]
pub fn [<set_ $field_name _async>](pager: &Pager, value: $type) -> Result<IOResult<()>> {
let page = match get_header_page_for_write(pager)? {
IOResult::Done(page) => page,
IOResult::IO => return Ok(IOResult::IO),
};
let page_inner = page.get();
let page_content = page_inner.contents.as_ref().unwrap();
let mut buf = page_content.buffer.borrow_mut();
let buf_slice = buf.as_mut_slice();
buf_slice[$offset..$offset + std::mem::size_of::<$type>()].copy_from_slice(&value.to_be_bytes());
turso_assert!(page.get().id == 1, "page must have number 1");
pager.add_dirty(&page);
Ok(IOResult::Done(()))
}
// Sync setter
#[allow(dead_code)]
pub fn [<set_ $field_name>](pager: &Pager, value: $type) -> Result<()> {
run_header_accessor_until_done(pager, || [<set_ $field_name _async>](pager, value))
}
}
};
}
// impl_header_field_accessor!(magic, [u8; 16], HEADER_OFFSET_MAGIC);
impl_header_field_accessor!(page_size_u16, u16, HEADER_OFFSET_PAGE_SIZE);
impl_header_field_accessor!(write_version, u8, HEADER_OFFSET_WRITE_VERSION);
impl_header_field_accessor!(read_version, u8, HEADER_OFFSET_READ_VERSION);
impl_header_field_accessor!(reserved_space, u8, HEADER_OFFSET_RESERVED_SPACE);
impl_header_field_accessor!(max_embed_frac, u8, HEADER_OFFSET_MAX_EMBED_FRAC);
impl_header_field_accessor!(min_embed_frac, u8, HEADER_OFFSET_MIN_EMBED_FRAC);
impl_header_field_accessor!(min_leaf_frac, u8, HEADER_OFFSET_MIN_LEAF_FRAC);
impl_header_field_accessor!(change_counter, u32, HEADER_OFFSET_CHANGE_COUNTER);
impl_header_field_accessor!(database_size, u32, HEADER_OFFSET_DATABASE_SIZE);
impl_header_field_accessor!(freelist_trunk_page, u32, HEADER_OFFSET_FREELIST_TRUNK_PAGE);
impl_header_field_accessor!(freelist_pages, u32, HEADER_OFFSET_FREELIST_PAGES);
impl_header_field_accessor!(schema_cookie, u32, HEADER_OFFSET_SCHEMA_COOKIE);
impl_header_field_accessor!(schema_format, u32, HEADER_OFFSET_SCHEMA_FORMAT);
impl_header_field_accessor!(
default_page_cache_size,
i32,
HEADER_OFFSET_DEFAULT_PAGE_CACHE_SIZE,
storage::sqlite3_ondisk::DEFAULT_CACHE_SIZE
);
impl_header_field_accessor!(
vacuum_mode_largest_root_page,
u32,
HEADER_OFFSET_VACUUM_MODE_LARGEST_ROOT_PAGE
);
impl_header_field_accessor!(text_encoding, u32, HEADER_OFFSET_TEXT_ENCODING);
impl_header_field_accessor!(user_version, i32, HEADER_OFFSET_USER_VERSION);
impl_header_field_accessor!(
incremental_vacuum_enabled,
u32,
HEADER_OFFSET_INCREMENTAL_VACUUM_ENABLED
);
impl_header_field_accessor!(application_id, i32, HEADER_OFFSET_APPLICATION_ID);
//impl_header_field_accessor!(reserved_for_expansion, [u8; 20], HEADER_OFFSET_RESERVED_FOR_EXPANSION);
impl_header_field_accessor!(version_valid_for, u32, HEADER_OFFSET_VERSION_VALID_FOR);
impl_header_field_accessor!(version_number, u32, HEADER_OFFSET_VERSION_NUMBER);
pub fn get_page_size(pager: &Pager) -> Result<u32> {
let size = get_page_size_u16(pager)?;
if size == 1 {
return Ok(MAX_PAGE_SIZE);
}
Ok(size as u32)
}
#[allow(dead_code)]
pub fn set_page_size(pager: &Pager, value: u32) -> Result<()> {
let page_size = if value == MAX_PAGE_SIZE {
1
} else {
value as u16
};
set_page_size_u16(pager, page_size)
}
#[allow(dead_code)]
pub fn get_page_size_async(pager: &Pager) -> Result<IOResult<u32>> {
match get_page_size_u16_async(pager)? {
IOResult::Done(size) => {
if size == 1 {
return Ok(IOResult::Done(MAX_PAGE_SIZE));
}
Ok(IOResult::Done(size as u32))
}
IOResult::IO => Ok(IOResult::IO),
}
}