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turso/core/storage/sqlite3_ondisk.rs
Pere Diaz Bou 081f09ce20 fix read wal max frame
2025-06-30 10:16:44 +02:00

1823 lines
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//! SQLite on-disk file format.
//!
//! SQLite stores data in a single database file, which is divided into fixed-size
//! pages:
//!
//! ```text
//! +----------+----------+----------+-----------------------------+----------+
//! | | | | | |
//! | Page 1 | Page 2 | Page 3 | ... | Page N |
//! | | | | | |
//! +----------+----------+----------+-----------------------------+----------+
//! ```
//!
//! The first page is special because it contains a 100 byte header at the beginning.
//!
//! Each page consists of a page header and N cells, which contain the records.
//!
//! ```text
//! +-----------------+----------------+---------------------+----------------+
//! | | | | |
//! | Page header | Cell pointer | Unallocated | Cell content |
//! | (8 or 12 bytes) | array | space | area |
//! | | | | |
//! +-----------------+----------------+---------------------+----------------+
//! ```
//!
//! The write-ahead log (WAL) is a separate file that contains the physical
//! log of changes to a database file. The file starts with a WAL header and
//! is followed by a sequence of WAL frames, which are database pages with
//! additional metadata.
//!
//! ```text
//! +-----------------+-----------------+-----------------+-----------------+
//! | | | | |
//! | WAL header | WAL frame 1 | WAL frame 2 | WAL frame N |
//! | | | | |
//! +-----------------+-----------------+-----------------+-----------------+
//! ```
//!
//! For more information, see the SQLite file format specification:
//!
//! https://www.sqlite.org/fileformat.html
#![allow(clippy::arc_with_non_send_sync)]
use tracing::{instrument, Level};
use crate::error::LimboError;
use crate::fast_lock::SpinLock;
use crate::io::{
Buffer, Complete, Completion, CompletionType, ReadCompletion, SyncCompletion, WriteCompletion,
};
use crate::storage::buffer_pool::BufferPool;
use crate::storage::database::DatabaseStorage;
use crate::storage::pager::Pager;
use crate::types::{
ImmutableRecord, RawSlice, RefValue, SerialType, SerialTypeKind, TextRef, TextSubtype,
};
use crate::{File, Result, WalFileShared};
use std::cell::{RefCell, UnsafeCell};
use std::collections::HashMap;
use std::mem::MaybeUninit;
use std::pin::Pin;
use std::rc::Rc;
use std::sync::atomic::{AtomicBool, AtomicU64, Ordering};
use std::sync::Arc;
use super::pager::PageRef;
use super::wal::LimboRwLock;
/// The size of the database header in bytes.
pub const DATABASE_HEADER_SIZE: usize = 100;
// DEFAULT_CACHE_SIZE negative values mean that we store the amount of pages a XKiB of memory can hold.
// We can calculate "real" cache size by diving by page size.
pub const DEFAULT_CACHE_SIZE: i32 = -2000;
// Minimum number of pages that cache can hold.
pub const MIN_PAGE_CACHE_SIZE: usize = 10;
/// The minimum page size in bytes.
pub const MIN_PAGE_SIZE: u32 = 512;
/// The maximum page size in bytes.
const MAX_PAGE_SIZE: u32 = 65536;
/// The default page size in bytes.
pub const DEFAULT_PAGE_SIZE: u16 = 4096;
pub const DATABASE_HEADER_PAGE_ID: usize = 1;
/// The database header.
/// The first 100 bytes of the database file comprise the database file header.
/// The database file header is divided into fields as shown by the table below.
/// All multibyte fields in the database file header are stored with the most significant byte first (big-endian).
#[derive(Debug, Clone)]
pub struct DatabaseHeader {
/// The header string: "SQLite format 3\0"
pub magic: [u8; 16],
/// The database page size in bytes. Must be a power of two between 512 and 32768 inclusive,
/// or the value 1 representing a page size of 65536.
pub page_size: u16,
/// File format write version. 1 for legacy; 2 for WAL.
pub write_version: u8,
/// File format read version. 1 for legacy; 2 for WAL.
pub read_version: u8,
/// Bytes of unused "reserved" space at the end of each page. Usually 0.
/// SQLite has the ability to set aside a small number of extra bytes at the end of every page for use by extensions.
/// These extra bytes are used, for example, by the SQLite Encryption Extension to store a nonce and/or
/// cryptographic checksum associated with each page.
pub reserved_space: u8,
/// Maximum embedded payload fraction. Must be 64.
pub max_embed_frac: u8,
/// Minimum embedded payload fraction. Must be 32.
pub min_embed_frac: u8,
/// Leaf payload fraction. Must be 32.
pub min_leaf_frac: u8,
/// File change counter, incremented when database is modified.
pub change_counter: u32,
/// Size of the database file in pages. The "in-header database size".
pub database_size: u32,
/// Page number of the first freelist trunk page.
pub freelist_trunk_page: u32,
/// Total number of freelist pages.
pub freelist_pages: u32,
/// The schema cookie. Incremented when the database schema changes.
pub schema_cookie: u32,
/// The schema format number. Supported formats are 1, 2, 3, and 4.
pub schema_format: u32,
/// Default page cache size.
pub default_page_cache_size: i32,
/// The page number of the largest root b-tree page when in auto-vacuum or
/// incremental-vacuum modes, or zero otherwise.
pub vacuum_mode_largest_root_page: u32,
/// The database text encoding. 1=UTF-8, 2=UTF-16le, 3=UTF-16be.
pub text_encoding: u32,
/// The "user version" as read and set by the user_version pragma.
pub user_version: i32,
/// True (non-zero) for incremental-vacuum mode. False (zero) otherwise.
pub incremental_vacuum_enabled: u32,
/// The "Application ID" set by PRAGMA application_id.
pub application_id: u32,
/// Reserved for expansion. Must be zero.
pub reserved_for_expansion: [u8; 20],
/// The version-valid-for number.
pub version_valid_for: u32,
/// SQLITE_VERSION_NUMBER
pub version_number: u32,
}
pub const WAL_HEADER_SIZE: usize = 32;
pub const WAL_FRAME_HEADER_SIZE: usize = 24;
// magic is a single number represented as WAL_MAGIC_LE but the big endian
// counterpart is just the same number with LSB set to 1.
pub const WAL_MAGIC_LE: u32 = 0x377f0682;
pub const WAL_MAGIC_BE: u32 = 0x377f0683;
/// The Write-Ahead Log (WAL) header.
/// The first 32 bytes of a WAL file comprise the WAL header.
/// The WAL header is divided into the following fields stored in big-endian order.
#[derive(Debug, Default, Clone, Copy)]
#[repr(C)] // This helps with encoding because rust does not respect the order in structs, so in
// this case we want to keep the order
pub struct WalHeader {
/// Magic number. 0x377f0682 or 0x377f0683
/// If the LSB is 0, checksums are native byte order, else checksums are serialized
pub magic: u32,
/// WAL format version. Currently 3007000
pub file_format: u32,
/// Database page size in bytes. Power of two between 512 and 65536 inclusive
pub page_size: u32,
/// Checkpoint sequence number. Increases with each checkpoint
pub checkpoint_seq: u32,
/// Random value used for the first salt in checksum calculations
/// TODO: Incremented with each checkpoint
pub salt_1: u32,
/// Random value used for the second salt in checksum calculations.
/// TODO: A different random value for each checkpoint
pub salt_2: u32,
/// First checksum value in the wal-header
pub checksum_1: u32,
/// Second checksum value in the wal-header
pub checksum_2: u32,
}
/// Immediately following the wal-header are zero or more frames.
/// Each frame consists of a 24-byte frame-header followed by <page-size> bytes of page data.
/// The frame-header is six big-endian 32-bit unsigned integer values, as follows:
#[allow(dead_code)]
#[derive(Debug, Default, Copy, Clone)]
pub struct WalFrameHeader {
/// Page number
page_number: u32,
/// For commit records, the size of the database file in pages after the commit.
/// For all other records, zero.
db_size: u32,
/// Salt-1 copied from the WAL header
salt_1: u32,
/// Salt-2 copied from the WAL header
salt_2: u32,
/// Checksum-1: Cumulative checksum up through and including this page
checksum_1: u32,
/// Checksum-2: Second half of the cumulative checksum
checksum_2: u32,
}
impl Default for DatabaseHeader {
fn default() -> Self {
Self {
magic: *b"SQLite format 3\0",
page_size: DEFAULT_PAGE_SIZE,
write_version: 2,
read_version: 2,
reserved_space: 0,
max_embed_frac: 64,
min_embed_frac: 32,
min_leaf_frac: 32,
change_counter: 1,
database_size: 0,
freelist_trunk_page: 0,
freelist_pages: 0,
schema_cookie: 0,
schema_format: 4, // latest format, new sqlite3 databases use this format
default_page_cache_size: DEFAULT_CACHE_SIZE,
vacuum_mode_largest_root_page: 0,
text_encoding: 1, // utf-8
user_version: 0,
incremental_vacuum_enabled: 0,
application_id: 0,
reserved_for_expansion: [0; 20],
version_valid_for: 3047000,
version_number: 3047000,
}
}
}
impl DatabaseHeader {
pub fn update_page_size(&mut self, size: u32) {
if !(MIN_PAGE_SIZE..=MAX_PAGE_SIZE).contains(&size) || (size & (size - 1) != 0) {
return;
}
self.page_size = if size == MAX_PAGE_SIZE {
1u16
} else {
size as u16
};
}
pub fn get_page_size(&self) -> u32 {
if self.page_size == 1 {
MAX_PAGE_SIZE
} else {
self.page_size as u32
}
}
}
pub fn write_header_to_buf(buf: &mut [u8], header: &DatabaseHeader) {
buf[0..16].copy_from_slice(&header.magic);
buf[16..18].copy_from_slice(&header.page_size.to_be_bytes());
buf[18] = header.write_version;
buf[19] = header.read_version;
buf[20] = header.reserved_space;
buf[21] = header.max_embed_frac;
buf[22] = header.min_embed_frac;
buf[23] = header.min_leaf_frac;
buf[24..28].copy_from_slice(&header.change_counter.to_be_bytes());
buf[28..32].copy_from_slice(&header.database_size.to_be_bytes());
buf[32..36].copy_from_slice(&header.freelist_trunk_page.to_be_bytes());
buf[36..40].copy_from_slice(&header.freelist_pages.to_be_bytes());
buf[40..44].copy_from_slice(&header.schema_cookie.to_be_bytes());
buf[44..48].copy_from_slice(&header.schema_format.to_be_bytes());
buf[48..52].copy_from_slice(&header.default_page_cache_size.to_be_bytes());
buf[52..56].copy_from_slice(&header.vacuum_mode_largest_root_page.to_be_bytes());
buf[56..60].copy_from_slice(&header.text_encoding.to_be_bytes());
buf[60..64].copy_from_slice(&header.user_version.to_be_bytes());
buf[64..68].copy_from_slice(&header.incremental_vacuum_enabled.to_be_bytes());
buf[68..72].copy_from_slice(&header.application_id.to_be_bytes());
buf[72..92].copy_from_slice(&header.reserved_for_expansion);
buf[92..96].copy_from_slice(&header.version_valid_for.to_be_bytes());
buf[96..100].copy_from_slice(&header.version_number.to_be_bytes());
}
#[repr(u8)]
#[derive(Debug, PartialEq, Clone, Copy)]
pub enum PageType {
IndexInterior = 2,
TableInterior = 5,
IndexLeaf = 10,
TableLeaf = 13,
}
impl PageType {
pub fn is_table(&self) -> bool {
match self {
PageType::IndexInterior | PageType::IndexLeaf => false,
PageType::TableInterior | PageType::TableLeaf => true,
}
}
}
impl TryFrom<u8> for PageType {
type Error = LimboError;
fn try_from(value: u8) -> Result<Self> {
match value {
2 => Ok(Self::IndexInterior),
5 => Ok(Self::TableInterior),
10 => Ok(Self::IndexLeaf),
13 => Ok(Self::TableLeaf),
_ => Err(LimboError::Corrupt(format!("Invalid page type: {}", value))),
}
}
}
#[derive(Debug, Clone)]
pub struct OverflowCell {
pub index: usize,
pub payload: Pin<Vec<u8>>,
}
#[derive(Debug)]
pub struct PageContent {
pub offset: usize,
pub buffer: Arc<RefCell<Buffer>>,
pub overflow_cells: Vec<OverflowCell>,
}
impl Clone for PageContent {
fn clone(&self) -> Self {
#[allow(clippy::arc_with_non_send_sync)]
Self {
offset: self.offset,
buffer: Arc::new(RefCell::new((*self.buffer.borrow()).clone())),
overflow_cells: self.overflow_cells.clone(),
}
}
}
impl PageContent {
pub fn new(offset: usize, buffer: Arc<RefCell<Buffer>>) -> Self {
Self {
offset,
buffer,
overflow_cells: Vec::new(),
}
}
pub fn page_type(&self) -> PageType {
self.read_u8(0).try_into().unwrap()
}
pub fn maybe_page_type(&self) -> Option<PageType> {
match self.read_u8(0).try_into() {
Ok(v) => Some(v),
Err(_) => None, // this could be an overflow page
}
}
#[allow(clippy::mut_from_ref)]
pub fn as_ptr(&self) -> &mut [u8] {
unsafe {
// unsafe trick to borrow twice
let buf_pointer = &self.buffer.as_ptr();
let buf = (*buf_pointer).as_mut().unwrap().as_mut_slice();
buf
}
}
pub fn read_u8(&self, pos: usize) -> u8 {
let buf = self.as_ptr();
buf[self.offset + pos]
}
pub fn read_u16(&self, pos: usize) -> u16 {
let buf = self.as_ptr();
u16::from_be_bytes([buf[self.offset + pos], buf[self.offset + pos + 1]])
}
pub fn read_u16_no_offset(&self, pos: usize) -> u16 {
let buf = self.as_ptr();
u16::from_be_bytes([buf[pos], buf[pos + 1]])
}
pub fn read_u32_no_offset(&self, pos: usize) -> u32 {
let buf = self.as_ptr();
u32::from_be_bytes([buf[pos], buf[pos + 1], buf[pos + 2], buf[pos + 3]])
}
pub fn read_u32(&self, pos: usize) -> u32 {
let buf = self.as_ptr();
read_u32(buf, self.offset + pos)
}
pub fn write_u8(&self, pos: usize, value: u8) {
tracing::trace!("write_u8(pos={}, value={})", pos, value);
let buf = self.as_ptr();
buf[self.offset + pos] = value;
}
pub fn write_u16(&self, pos: usize, value: u16) {
tracing::trace!("write_u16(pos={}, value={})", pos, value);
let buf = self.as_ptr();
buf[self.offset + pos..self.offset + pos + 2].copy_from_slice(&value.to_be_bytes());
}
pub fn write_u16_no_offset(&self, pos: usize, value: u16) {
tracing::trace!("write_u16(pos={}, value={})", pos, value);
let buf = self.as_ptr();
buf[pos..pos + 2].copy_from_slice(&value.to_be_bytes());
}
pub fn write_u32(&self, pos: usize, value: u32) {
tracing::trace!("write_u32(pos={}, value={})", pos, value);
let buf = self.as_ptr();
buf[self.offset + pos..self.offset + pos + 4].copy_from_slice(&value.to_be_bytes());
}
/// The second field of the b-tree page header is the offset of the first freeblock, or zero if there are no freeblocks on the page.
/// A freeblock is a structure used to identify unallocated space within a b-tree page.
/// Freeblocks are organized as a chain.
///
/// To be clear, freeblocks do not mean the regular unallocated free space to the left of the cell content area pointer, but instead
/// blocks of at least 4 bytes WITHIN the cell content area that are not in use due to e.g. deletions.
pub fn first_freeblock(&self) -> u16 {
self.read_u16(1)
}
/// The number of cells on the page.
pub fn cell_count(&self) -> usize {
self.read_u16(3) as usize
}
/// The size of the cell pointer array in bytes.
/// 2 bytes per cell pointer
pub fn cell_pointer_array_size(&self) -> usize {
const CELL_POINTER_SIZE_BYTES: usize = 2;
self.cell_count() * CELL_POINTER_SIZE_BYTES
}
/// The start of the unallocated region.
/// Effectively: the offset after the page header + the cell pointer array.
pub fn unallocated_region_start(&self) -> usize {
let (cell_ptr_array_start, cell_ptr_array_size) = self.cell_pointer_array_offset_and_size();
cell_ptr_array_start + cell_ptr_array_size
}
pub fn unallocated_region_size(&self) -> usize {
self.cell_content_area() as usize - self.unallocated_region_start()
}
/// The start of the cell content area.
/// SQLite strives to place cells as far toward the end of the b-tree page as it can,
/// in order to leave space for future growth of the cell pointer array.
/// = the cell content area pointer moves leftward as cells are added to the page
pub fn cell_content_area(&self) -> u16 {
self.read_u16(5)
}
/// The size of the page header in bytes.
/// 8 bytes for leaf pages, 12 bytes for interior pages (due to storing rightmost child pointer)
pub fn header_size(&self) -> usize {
match self.page_type() {
PageType::IndexInterior => 12,
PageType::TableInterior => 12,
PageType::IndexLeaf => 8,
PageType::TableLeaf => 8,
}
}
/// The total number of bytes in all fragments is stored in the fifth field of the b-tree page header.
/// Fragments are isolated groups of 1, 2, or 3 unused bytes within the cell content area.
pub fn num_frag_free_bytes(&self) -> u8 {
self.read_u8(7)
}
pub fn rightmost_pointer(&self) -> Option<u32> {
match self.page_type() {
PageType::IndexInterior => Some(self.read_u32(8)),
PageType::TableInterior => Some(self.read_u32(8)),
PageType::IndexLeaf => None,
PageType::TableLeaf => None,
}
}
pub fn rightmost_pointer_raw(&self) -> Option<*mut u8> {
match self.page_type() {
PageType::IndexInterior | PageType::TableInterior => {
Some(unsafe { self.as_ptr().as_mut_ptr().add(self.offset + 8) })
}
PageType::IndexLeaf => None,
PageType::TableLeaf => None,
}
}
pub fn cell_get(
&self,
idx: usize,
payload_overflow_threshold_max: usize,
payload_overflow_threshold_min: usize,
usable_size: usize,
) -> Result<BTreeCell> {
tracing::trace!("cell_get(idx={})", idx);
let buf = self.as_ptr();
let ncells = self.cell_count();
// the page header is 12 bytes for interior pages, 8 bytes for leaf pages
// this is because the 4 last bytes in the interior page's header are used for the rightmost pointer.
let cell_pointer_array_start = self.header_size();
assert!(
idx < ncells,
"cell_get: idx out of bounds: idx={}, ncells={}",
idx,
ncells
);
let cell_pointer = cell_pointer_array_start + (idx * 2);
let cell_pointer = self.read_u16(cell_pointer) as usize;
// SAFETY: this buffer is valid as long as the page is alive. We could store the page in the cell and do some lifetime magic
// but that is extra memory for no reason at all. Just be careful like in the old times :).
let static_buf: &'static [u8] = unsafe { std::mem::transmute::<&[u8], &'static [u8]>(buf) };
read_btree_cell(
static_buf,
&self.page_type(),
cell_pointer,
payload_overflow_threshold_max,
payload_overflow_threshold_min,
usable_size,
)
}
/// Read the rowid of a table interior cell.
#[inline(always)]
pub fn cell_table_interior_read_rowid(&self, idx: usize) -> Result<i64> {
debug_assert!(self.page_type() == PageType::TableInterior);
let buf = self.as_ptr();
const INTERIOR_PAGE_HEADER_SIZE_BYTES: usize = 12;
let cell_pointer_array_start = INTERIOR_PAGE_HEADER_SIZE_BYTES;
let cell_pointer = cell_pointer_array_start + (idx * 2);
let cell_pointer = self.read_u16(cell_pointer) as usize;
const LEFT_CHILD_PAGE_SIZE_BYTES: usize = 4;
let (rowid, _) = read_varint(&buf[cell_pointer + LEFT_CHILD_PAGE_SIZE_BYTES..])?;
Ok(rowid as i64)
}
/// Read the left child page of a table interior cell.
#[inline(always)]
pub fn cell_table_interior_read_left_child_page(&self, idx: usize) -> Result<u32> {
debug_assert!(self.page_type() == PageType::TableInterior);
let buf = self.as_ptr();
const INTERIOR_PAGE_HEADER_SIZE_BYTES: usize = 12;
let cell_pointer_array_start = INTERIOR_PAGE_HEADER_SIZE_BYTES;
let cell_pointer = cell_pointer_array_start + (idx * 2);
let cell_pointer = self.read_u16(cell_pointer) as usize;
Ok(u32::from_be_bytes([
buf[cell_pointer],
buf[cell_pointer + 1],
buf[cell_pointer + 2],
buf[cell_pointer + 3],
]))
}
/// Read the rowid of a table leaf cell.
#[inline(always)]
pub fn cell_table_leaf_read_rowid(&self, idx: usize) -> Result<i64> {
debug_assert!(self.page_type() == PageType::TableLeaf);
let buf = self.as_ptr();
const LEAF_PAGE_HEADER_SIZE_BYTES: usize = 8;
let cell_pointer_array_start = LEAF_PAGE_HEADER_SIZE_BYTES;
let cell_pointer = cell_pointer_array_start + (idx * 2);
let cell_pointer = self.read_u16(cell_pointer) as usize;
let mut pos = cell_pointer;
let (_, nr) = read_varint(&buf[pos..])?;
pos += nr;
let (rowid, _) = read_varint(&buf[pos..])?;
Ok(rowid as i64)
}
/// The cell pointer array of a b-tree page immediately follows the b-tree page header.
/// Let K be the number of cells on the btree.
/// The cell pointer array consists of K 2-byte integer offsets to the cell contents.
/// The cell pointers are arranged in key order with:
/// - left-most cell (the cell with the smallest key) first and
/// - the right-most cell (the cell with the largest key) last.
pub fn cell_pointer_array_offset_and_size(&self) -> (usize, usize) {
let header_size = self.header_size();
(self.offset + header_size, self.cell_pointer_array_size())
}
/// Get region of a cell's payload
pub fn cell_get_raw_region(
&self,
idx: usize,
payload_overflow_threshold_max: usize,
payload_overflow_threshold_min: usize,
usable_size: usize,
) -> (usize, usize) {
let buf = self.as_ptr();
let ncells = self.cell_count();
let (cell_pointer_array_start, _) = self.cell_pointer_array_offset_and_size();
assert!(idx < ncells, "cell_get: idx out of bounds");
let cell_pointer = cell_pointer_array_start + (idx * 2); // pointers are 2 bytes each
let cell_pointer = self.read_u16_no_offset(cell_pointer) as usize;
let start = cell_pointer;
let len = match self.page_type() {
PageType::IndexInterior => {
let (len_payload, n_payload) = read_varint(&buf[cell_pointer + 4..]).unwrap();
let (overflows, to_read) = payload_overflows(
len_payload as usize,
payload_overflow_threshold_max,
payload_overflow_threshold_min,
usable_size,
);
if overflows {
4 + to_read + n_payload
} else {
4 + len_payload as usize + n_payload
}
}
PageType::TableInterior => {
let (_, n_rowid) = read_varint(&buf[cell_pointer + 4..]).unwrap();
4 + n_rowid
}
PageType::IndexLeaf => {
let (len_payload, n_payload) = read_varint(&buf[cell_pointer..]).unwrap();
let (overflows, to_read) = payload_overflows(
len_payload as usize,
payload_overflow_threshold_max,
payload_overflow_threshold_min,
usable_size,
);
if overflows {
to_read + n_payload
} else {
len_payload as usize + n_payload
}
}
PageType::TableLeaf => {
let (len_payload, n_payload) = read_varint(&buf[cell_pointer..]).unwrap();
let (_, n_rowid) = read_varint(&buf[cell_pointer + n_payload..]).unwrap();
let (overflows, to_read) = payload_overflows(
len_payload as usize,
payload_overflow_threshold_max,
payload_overflow_threshold_min,
usable_size,
);
if overflows {
to_read + n_payload + n_rowid
} else {
len_payload as usize + n_payload + n_rowid
}
}
};
(start, len)
}
pub fn is_leaf(&self) -> bool {
match self.page_type() {
PageType::IndexInterior => false,
PageType::TableInterior => false,
PageType::IndexLeaf => true,
PageType::TableLeaf => true,
}
}
pub fn write_database_header(&self, header: &DatabaseHeader) {
let buf = self.as_ptr();
write_header_to_buf(buf, header);
}
pub fn debug_print_freelist(&self, usable_space: u16) {
let mut pc = self.first_freeblock() as usize;
let mut block_num = 0;
println!("---- Free List Blocks ----");
println!("first freeblock pointer: {}", pc);
println!("cell content area: {}", self.cell_content_area());
println!("fragmented bytes: {}", self.num_frag_free_bytes());
while pc != 0 && pc <= usable_space as usize {
let next = self.read_u16_no_offset(pc);
let size = self.read_u16_no_offset(pc + 2);
println!(
"block {}: position={}, size={}, next={}",
block_num, pc, size, next
);
pc = next as usize;
block_num += 1;
}
println!("--------------");
}
}
pub fn begin_read_page(
db_file: Arc<dyn DatabaseStorage>,
buffer_pool: Rc<BufferPool>,
page: PageRef,
page_idx: usize,
) -> Result<()> {
tracing::trace!("begin_read_btree_page(page_idx = {})", page_idx);
let buf = buffer_pool.get();
let drop_fn = Rc::new(move |buf| {
let buffer_pool = buffer_pool.clone();
buffer_pool.put(buf);
});
#[allow(clippy::arc_with_non_send_sync)]
let buf = Arc::new(RefCell::new(Buffer::new(buf, drop_fn)));
let complete = Box::new(move |buf: Arc<RefCell<Buffer>>| {
let page = page.clone();
if finish_read_page(page_idx, buf, page.clone()).is_err() {
page.set_error();
}
});
let c = Completion::new(CompletionType::Read(ReadCompletion::new(buf, complete)));
db_file.read_page(page_idx, c)?;
Ok(())
}
pub fn finish_read_page(
page_idx: usize,
buffer_ref: Arc<RefCell<Buffer>>,
page: PageRef,
) -> Result<()> {
tracing::trace!("finish_read_btree_page(page_idx = {})", page_idx);
let pos = if page_idx == DATABASE_HEADER_PAGE_ID {
DATABASE_HEADER_SIZE
} else {
0
};
let inner = PageContent::new(pos, buffer_ref.clone());
{
page.get().contents.replace(inner);
page.set_uptodate();
page.clear_locked();
page.set_loaded();
}
Ok(())
}
pub fn begin_write_btree_page(
pager: &Pager,
page: &PageRef,
write_counter: Rc<RefCell<usize>>,
) -> Result<()> {
tracing::trace!("begin_write_btree_page(page={})", page.get().id);
let page_source = &pager.db_file;
let page_finish = page.clone();
let page_id = page.get().id;
tracing::trace!("begin_write_btree_page(page_id={})", page_id);
let buffer = {
let page = page.get();
let contents = page.contents.as_ref().unwrap();
contents.buffer.clone()
};
*write_counter.borrow_mut() += 1;
let write_complete = {
let buf_copy = buffer.clone();
Box::new(move |bytes_written: i32| {
tracing::trace!("finish_write_btree_page");
let buf_copy = buf_copy.clone();
let buf_len = buf_copy.borrow().len();
*write_counter.borrow_mut() -= 1;
page_finish.clear_dirty();
if bytes_written < buf_len as i32 {
tracing::error!("wrote({bytes_written}) less than expected({buf_len})");
}
})
};
let c = Completion::new(CompletionType::Write(WriteCompletion::new(write_complete)));
page_source.write_page(page_id, buffer.clone(), c)?;
Ok(())
}
pub fn begin_sync(db_file: Arc<dyn DatabaseStorage>, syncing: Rc<RefCell<bool>>) -> Result<()> {
assert!(!*syncing.borrow());
*syncing.borrow_mut() = true;
let completion = Completion::new(CompletionType::Sync(SyncCompletion {
complete: Box::new(move |_| {
*syncing.borrow_mut() = false;
}),
}));
#[allow(clippy::arc_with_non_send_sync)]
db_file.sync(completion)?;
Ok(())
}
#[allow(clippy::enum_variant_names)]
#[derive(Debug, Clone)]
pub enum BTreeCell {
TableInteriorCell(TableInteriorCell),
TableLeafCell(TableLeafCell),
IndexInteriorCell(IndexInteriorCell),
IndexLeafCell(IndexLeafCell),
}
#[derive(Debug, Clone)]
pub struct TableInteriorCell {
pub _left_child_page: u32,
pub _rowid: i64,
}
#[derive(Debug, Clone)]
pub struct TableLeafCell {
pub _rowid: i64,
/// Payload of cell, if it overflows it won't include overflowed payload.
pub _payload: &'static [u8],
/// This is the complete payload size including overflow pages.
pub payload_size: u64,
pub first_overflow_page: Option<u32>,
}
#[derive(Debug, Clone)]
pub struct IndexInteriorCell {
pub left_child_page: u32,
pub payload: &'static [u8],
/// This is the complete payload size including overflow pages.
pub payload_size: u64,
pub first_overflow_page: Option<u32>,
}
#[derive(Debug, Clone)]
pub struct IndexLeafCell {
pub payload: &'static [u8],
pub first_overflow_page: Option<u32>,
/// This is the complete payload size including overflow pages.
pub payload_size: u64,
}
/// read_btree_cell contructs a BTreeCell which is basically a wrapper around pointer to the payload of a cell.
/// buffer input "page" is static because we want the cell to point to the data in the page in case it has any payload.
pub fn read_btree_cell(
page: &'static [u8],
page_type: &PageType,
pos: usize,
max_local: usize,
min_local: usize,
usable_size: usize,
) -> Result<BTreeCell> {
match page_type {
PageType::IndexInterior => {
let mut pos = pos;
let left_child_page =
u32::from_be_bytes([page[pos], page[pos + 1], page[pos + 2], page[pos + 3]]);
pos += 4;
let (payload_size, nr) = read_varint(&page[pos..])?;
pos += nr;
let (overflows, to_read) =
payload_overflows(payload_size as usize, max_local, min_local, usable_size);
let to_read = if overflows { to_read } else { page.len() - pos };
let (payload, first_overflow_page) =
read_payload(&page[pos..pos + to_read], payload_size as usize);
Ok(BTreeCell::IndexInteriorCell(IndexInteriorCell {
left_child_page,
payload,
first_overflow_page,
payload_size,
}))
}
PageType::TableInterior => {
let mut pos = pos;
let left_child_page =
u32::from_be_bytes([page[pos], page[pos + 1], page[pos + 2], page[pos + 3]]);
pos += 4;
let (rowid, _) = read_varint(&page[pos..])?;
Ok(BTreeCell::TableInteriorCell(TableInteriorCell {
_left_child_page: left_child_page,
_rowid: rowid as i64,
}))
}
PageType::IndexLeaf => {
let mut pos = pos;
let (payload_size, nr) = read_varint(&page[pos..])?;
pos += nr;
let (overflows, to_read) =
payload_overflows(payload_size as usize, max_local, min_local, usable_size);
let to_read = if overflows { to_read } else { page.len() - pos };
let (payload, first_overflow_page) =
read_payload(&page[pos..pos + to_read], payload_size as usize);
Ok(BTreeCell::IndexLeafCell(IndexLeafCell {
payload,
first_overflow_page,
payload_size,
}))
}
PageType::TableLeaf => {
let mut pos = pos;
let (payload_size, nr) = read_varint(&page[pos..])?;
pos += nr;
let (rowid, nr) = read_varint(&page[pos..])?;
pos += nr;
let (overflows, to_read) =
payload_overflows(payload_size as usize, max_local, min_local, usable_size);
let to_read = if overflows { to_read } else { page.len() - pos };
let (payload, first_overflow_page) =
read_payload(&page[pos..pos + to_read], payload_size as usize);
Ok(BTreeCell::TableLeafCell(TableLeafCell {
_rowid: rowid as i64,
_payload: payload,
first_overflow_page,
payload_size,
}))
}
}
}
/// read_payload takes in the unread bytearray with the payload size
/// and returns the payload on the page, and optionally the first overflow page number.
#[allow(clippy::readonly_write_lock)]
fn read_payload(unread: &'static [u8], payload_size: usize) -> (&'static [u8], Option<u32>) {
let cell_len = unread.len();
// We will let overflow be constructed back if needed or requested.
if payload_size <= cell_len {
// fit within 1 page
(&unread[..payload_size], None)
} else {
// overflow
let first_overflow_page = u32::from_be_bytes([
unread[cell_len - 4],
unread[cell_len - 3],
unread[cell_len - 2],
unread[cell_len - 1],
]);
(&unread[..cell_len - 4], Some(first_overflow_page))
}
}
#[inline(always)]
pub fn validate_serial_type(value: u64) -> Result<()> {
if !SerialType::u64_is_valid_serial_type(value) {
crate::bail_corrupt_error!("Invalid serial type: {}", value);
}
Ok(())
}
pub struct SmallVec<T, const N: usize = 64> {
/// Stack allocated data
pub data: [std::mem::MaybeUninit<T>; N],
/// Length of the vector, accounting for both stack and heap allocated data
pub len: usize,
/// Extra data on heap
pub extra_data: Option<Vec<T>>,
}
impl<T: Default + Copy, const N: usize> SmallVec<T, N> {
pub fn new() -> Self {
Self {
data: unsafe { std::mem::MaybeUninit::uninit().assume_init() },
len: 0,
extra_data: None,
}
}
pub fn push(&mut self, value: T) {
if self.len < self.data.len() {
self.data[self.len] = MaybeUninit::new(value);
self.len += 1;
} else {
if self.extra_data.is_none() {
self.extra_data = Some(Vec::new());
}
self.extra_data.as_mut().unwrap().push(value);
self.len += 1;
}
}
fn get_from_heap(&self, index: usize) -> T {
assert!(self.extra_data.is_some());
assert!(index >= self.data.len());
let extra_data_index = index - self.data.len();
let extra_data = self.extra_data.as_ref().unwrap();
assert!(extra_data_index < extra_data.len());
extra_data[extra_data_index]
}
pub fn get(&self, index: usize) -> Option<T> {
if index >= self.len {
return None;
}
let data_is_on_stack = index < self.data.len();
if data_is_on_stack {
// SAFETY: We know this index is initialized we checked for index < self.len earlier above.
unsafe { Some(self.data[index].assume_init()) }
} else {
Some(self.get_from_heap(index))
}
}
}
impl<T: Default + Copy, const N: usize> SmallVec<T, N> {
pub fn iter(&self) -> SmallVecIter<'_, T, N> {
SmallVecIter { vec: self, pos: 0 }
}
}
pub struct SmallVecIter<'a, T, const N: usize> {
vec: &'a SmallVec<T, N>,
pos: usize,
}
impl<T: Default + Copy, const N: usize> Iterator for SmallVecIter<'_, T, N> {
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
let next = self.vec.get(self.pos)?;
self.pos += 1;
Some(next)
}
}
pub fn read_record(payload: &[u8], reuse_immutable: &mut ImmutableRecord) -> Result<()> {
// Let's clear previous use
reuse_immutable.invalidate();
// Copy payload to ImmutableRecord in order to make RefValue that point to this new buffer.
// By reusing this immutable record we make it less allocation expensive.
reuse_immutable.start_serialization(payload);
let mut pos = 0;
let (header_size, nr) = read_varint(payload)?;
assert!((header_size as usize) >= nr);
let mut header_size = (header_size as usize) - nr;
pos += nr;
let mut serial_types = SmallVec::<u64, 64>::new();
while header_size > 0 {
let (serial_type, nr) = read_varint(&reuse_immutable.get_payload()[pos..])?;
validate_serial_type(serial_type)?;
serial_types.push(serial_type);
pos += nr;
assert!(header_size >= nr);
header_size -= nr;
}
for &serial_type in &serial_types.data[..serial_types.len.min(serial_types.data.len())] {
let (value, n) = read_value(&reuse_immutable.get_payload()[pos..], unsafe {
serial_type.assume_init().try_into()?
})?;
pos += n;
reuse_immutable.add_value(value);
}
if let Some(extra) = serial_types.extra_data.as_ref() {
for serial_type in extra {
let (value, n) = read_value(
&reuse_immutable.get_payload()[pos..],
(*serial_type).try_into()?,
)?;
pos += n;
reuse_immutable.add_value(value);
}
}
Ok(())
}
/// Reads a value that might reference the buffer it is reading from. Be sure to store RefValue with the buffer
/// always.
#[inline(always)]
pub fn read_value(buf: &[u8], serial_type: SerialType) -> Result<(RefValue, usize)> {
match serial_type.kind() {
SerialTypeKind::Null => Ok((RefValue::Null, 0)),
SerialTypeKind::I8 => {
if buf.is_empty() {
crate::bail_corrupt_error!("Invalid UInt8 value");
}
let val = buf[0] as i8;
Ok((RefValue::Integer(val as i64), 1))
}
SerialTypeKind::I16 => {
if buf.len() < 2 {
crate::bail_corrupt_error!("Invalid BEInt16 value");
}
Ok((
RefValue::Integer(i16::from_be_bytes([buf[0], buf[1]]) as i64),
2,
))
}
SerialTypeKind::I24 => {
if buf.len() < 3 {
crate::bail_corrupt_error!("Invalid BEInt24 value");
}
let sign_extension = if buf[0] <= 127 { 0 } else { 255 };
Ok((
RefValue::Integer(
i32::from_be_bytes([sign_extension, buf[0], buf[1], buf[2]]) as i64
),
3,
))
}
SerialTypeKind::I32 => {
if buf.len() < 4 {
crate::bail_corrupt_error!("Invalid BEInt32 value");
}
Ok((
RefValue::Integer(i32::from_be_bytes([buf[0], buf[1], buf[2], buf[3]]) as i64),
4,
))
}
SerialTypeKind::I48 => {
if buf.len() < 6 {
crate::bail_corrupt_error!("Invalid BEInt48 value");
}
let sign_extension = if buf[0] <= 127 { 0 } else { 255 };
Ok((
RefValue::Integer(i64::from_be_bytes([
sign_extension,
sign_extension,
buf[0],
buf[1],
buf[2],
buf[3],
buf[4],
buf[5],
])),
6,
))
}
SerialTypeKind::I64 => {
if buf.len() < 8 {
crate::bail_corrupt_error!("Invalid BEInt64 value");
}
Ok((
RefValue::Integer(i64::from_be_bytes([
buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7],
])),
8,
))
}
SerialTypeKind::F64 => {
if buf.len() < 8 {
crate::bail_corrupt_error!("Invalid BEFloat64 value");
}
Ok((
RefValue::Float(f64::from_be_bytes([
buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6], buf[7],
])),
8,
))
}
SerialTypeKind::ConstInt0 => Ok((RefValue::Integer(0), 0)),
SerialTypeKind::ConstInt1 => Ok((RefValue::Integer(1), 0)),
SerialTypeKind::Blob => {
let content_size = serial_type.size();
if buf.len() < content_size {
crate::bail_corrupt_error!("Invalid Blob value");
}
if content_size == 0 {
Ok((RefValue::Blob(RawSlice::new(std::ptr::null(), 0)), 0))
} else {
let ptr = &buf[0] as *const u8;
let slice = RawSlice::new(ptr, content_size);
Ok((RefValue::Blob(slice), content_size))
}
}
SerialTypeKind::Text => {
let content_size = serial_type.size();
if buf.len() < content_size {
crate::bail_corrupt_error!(
"Invalid String value, length {} < expected length {}",
buf.len(),
content_size
);
}
let slice = if content_size == 0 {
RawSlice::new(std::ptr::null(), 0)
} else {
let ptr = &buf[0] as *const u8;
RawSlice::new(ptr, content_size)
};
Ok((
RefValue::Text(TextRef {
value: slice,
subtype: TextSubtype::Text,
}),
content_size,
))
}
}
}
#[inline(always)]
pub fn read_varint(buf: &[u8]) -> Result<(u64, usize)> {
let mut v: u64 = 0;
for i in 0..8 {
match buf.get(i) {
Some(c) => {
v = (v << 7) + (c & 0x7f) as u64;
if (c & 0x80) == 0 {
return Ok((v, i + 1));
}
}
None => {
crate::bail_corrupt_error!("Invalid varint");
}
}
}
v = (v << 8) + buf[8] as u64;
Ok((v, 9))
}
pub fn write_varint(buf: &mut [u8], value: u64) -> usize {
if value <= 0x7f {
buf[0] = (value & 0x7f) as u8;
return 1;
}
if value <= 0x3fff {
buf[0] = (((value >> 7) & 0x7f) | 0x80) as u8;
buf[1] = (value & 0x7f) as u8;
return 2;
}
let mut value = value;
if (value & ((0xff000000_u64) << 32)) > 0 {
buf[8] = value as u8;
value >>= 8;
for i in (0..8).rev() {
buf[i] = ((value & 0x7f) | 0x80) as u8;
value >>= 7;
}
return 9;
}
let mut encoded: [u8; 10] = [0; 10];
let mut bytes = value;
let mut n = 0;
while bytes != 0 {
let v = 0x80 | (bytes & 0x7f);
encoded[n] = v as u8;
bytes >>= 7;
n += 1;
}
encoded[0] &= 0x7f;
for i in 0..n {
buf[i] = encoded[n - 1 - i];
}
n
}
pub fn write_varint_to_vec(value: u64, payload: &mut Vec<u8>) {
let mut varint = [0u8; 9];
let n = write_varint(&mut varint, value);
payload.extend_from_slice(&varint[0..n]);
}
/// We need to read the WAL file on open to reconstruct the WAL frame cache.
pub fn read_entire_wal_dumb(file: &Arc<dyn File>) -> Result<Arc<UnsafeCell<WalFileShared>>> {
let drop_fn = Rc::new(|_buf| {});
let size = file.size()?;
#[allow(clippy::arc_with_non_send_sync)]
let buf_for_pread = Arc::new(RefCell::new(Buffer::allocate(size as usize, drop_fn)));
let header = Arc::new(SpinLock::new(WalHeader::default()));
#[allow(clippy::arc_with_non_send_sync)]
let wal_file_shared_ret = Arc::new(UnsafeCell::new(WalFileShared {
wal_header: header.clone(),
min_frame: AtomicU64::new(0),
max_frame: AtomicU64::new(0),
nbackfills: AtomicU64::new(0),
frame_cache: Arc::new(SpinLock::new(HashMap::new())),
pages_in_frames: Arc::new(SpinLock::new(Vec::new())),
last_checksum: (0, 0),
file: file.clone(),
read_locks: [
LimboRwLock::new(),
LimboRwLock::new(),
LimboRwLock::new(),
LimboRwLock::new(),
LimboRwLock::new(),
],
write_lock: LimboRwLock::new(),
loaded: AtomicBool::new(false),
}));
let wal_file_shared_for_completion = wal_file_shared_ret.clone();
let complete: Box<Complete> = Box::new(move |buf: Arc<RefCell<Buffer>>| {
let buf = buf.borrow();
let buf_slice = buf.as_slice();
let mut header_locked = header.lock();
// Read header
header_locked.magic =
u32::from_be_bytes([buf_slice[0], buf_slice[1], buf_slice[2], buf_slice[3]]);
header_locked.file_format =
u32::from_be_bytes([buf_slice[4], buf_slice[5], buf_slice[6], buf_slice[7]]);
header_locked.page_size =
u32::from_be_bytes([buf_slice[8], buf_slice[9], buf_slice[10], buf_slice[11]]);
header_locked.checkpoint_seq =
u32::from_be_bytes([buf_slice[12], buf_slice[13], buf_slice[14], buf_slice[15]]);
header_locked.salt_1 =
u32::from_be_bytes([buf_slice[16], buf_slice[17], buf_slice[18], buf_slice[19]]);
header_locked.salt_2 =
u32::from_be_bytes([buf_slice[20], buf_slice[21], buf_slice[22], buf_slice[23]]);
header_locked.checksum_1 =
u32::from_be_bytes([buf_slice[24], buf_slice[25], buf_slice[26], buf_slice[27]]);
header_locked.checksum_2 =
u32::from_be_bytes([buf_slice[28], buf_slice[29], buf_slice[30], buf_slice[31]]);
// Read frames into frame_cache and pages_in_frames
if buf_slice.len() < WAL_HEADER_SIZE {
panic!("WAL file too small for header");
}
let use_native_endian_checksum =
cfg!(target_endian = "big") == ((header_locked.magic & 1) != 0);
let calculated_header_checksum = checksum_wal(
&buf_slice[0..24],
&header_locked,
(0, 0),
use_native_endian_checksum,
);
if calculated_header_checksum != (header_locked.checksum_1, header_locked.checksum_2) {
panic!(
"WAL header checksum mismatch. Expected ({}, {}), Got ({}, {})",
header_locked.checksum_1,
header_locked.checksum_2,
calculated_header_checksum.0,
calculated_header_checksum.1
);
}
let mut cumulative_checksum = (header_locked.checksum_1, header_locked.checksum_2);
let page_size_u32 = header_locked.page_size;
if !(MIN_PAGE_SIZE..=MAX_PAGE_SIZE).contains(&page_size_u32)
|| page_size_u32.count_ones() != 1
{
panic!("Invalid page size in WAL header: {}", page_size_u32);
}
let page_size = page_size_u32 as usize;
let mut current_offset = WAL_HEADER_SIZE;
let mut frame_idx = 1_u64;
let wfs_data = unsafe { &mut *wal_file_shared_for_completion.get() };
while current_offset + WAL_FRAME_HEADER_SIZE + page_size <= buf_slice.len() {
let frame_header_slice =
&buf_slice[current_offset..current_offset + WAL_FRAME_HEADER_SIZE];
let page_data_slice = &buf_slice[current_offset + WAL_FRAME_HEADER_SIZE
..current_offset + WAL_FRAME_HEADER_SIZE + page_size];
let frame_h_page_number =
u32::from_be_bytes(frame_header_slice[0..4].try_into().unwrap());
let frame_h_db_size = u32::from_be_bytes(frame_header_slice[4..8].try_into().unwrap());
let frame_h_salt_1 = u32::from_be_bytes(frame_header_slice[8..12].try_into().unwrap());
let frame_h_salt_2 = u32::from_be_bytes(frame_header_slice[12..16].try_into().unwrap());
let frame_h_checksum_1 =
u32::from_be_bytes(frame_header_slice[16..20].try_into().unwrap());
let frame_h_checksum_2 =
u32::from_be_bytes(frame_header_slice[20..24].try_into().unwrap());
// It contains more frames with mismatched SALT values, which means they're leftovers from previous checkpoints
if frame_h_salt_1 != header_locked.salt_1 || frame_h_salt_2 != header_locked.salt_2 {
tracing::trace!(
"WAL frame salt mismatch: expected ({}, {}), got ({}, {}), ignoring frame",
header_locked.salt_1,
header_locked.salt_2,
frame_h_salt_1,
frame_h_salt_2
);
break;
}
let checksum_after_fh_meta = checksum_wal(
&frame_header_slice[0..8],
&header_locked,
cumulative_checksum,
use_native_endian_checksum,
);
let calculated_frame_checksum = checksum_wal(
page_data_slice,
&header_locked,
checksum_after_fh_meta,
use_native_endian_checksum,
);
if calculated_frame_checksum != (frame_h_checksum_1, frame_h_checksum_2) {
panic!(
"WAL frame checksum mismatch. Expected ({}, {}), Got ({}, {})",
frame_h_checksum_1,
frame_h_checksum_2,
calculated_frame_checksum.0,
calculated_frame_checksum.1
);
}
cumulative_checksum = calculated_frame_checksum;
wfs_data
.frame_cache
.lock()
.entry(frame_h_page_number as u64)
.or_default()
.push(frame_idx);
wfs_data
.pages_in_frames
.lock()
.push(frame_h_page_number as u64);
let is_commit_record = frame_h_db_size > 0;
if is_commit_record {
wfs_data.max_frame.store(frame_idx, Ordering::SeqCst);
wfs_data.last_checksum = cumulative_checksum;
}
frame_idx += 1;
current_offset += WAL_FRAME_HEADER_SIZE + page_size;
}
wfs_data.loaded.store(true, Ordering::SeqCst);
});
let c = Completion::new(CompletionType::Read(ReadCompletion::new(
buf_for_pread,
complete,
)));
file.pread(0, c)?;
Ok(wal_file_shared_ret)
}
pub fn begin_read_wal_frame(
io: &Arc<dyn File>,
offset: usize,
buffer_pool: Rc<BufferPool>,
complete: Box<dyn Fn(Arc<RefCell<Buffer>>)>,
) -> Result<Arc<Completion>> {
tracing::trace!("begin_read_wal_frame(offset={})", offset);
let buf = buffer_pool.get();
let drop_fn = Rc::new(move |buf| {
let buffer_pool = buffer_pool.clone();
buffer_pool.put(buf);
});
let buf = Arc::new(RefCell::new(Buffer::new(buf, drop_fn)));
#[allow(clippy::arc_with_non_send_sync)]
let c = Completion::new(CompletionType::Read(ReadCompletion::new(buf, complete)));
let c = io.pread(offset, c)?;
Ok(c)
}
#[instrument(skip(io, page, write_counter, wal_header, checksums), level = Level::TRACE)]
#[allow(clippy::too_many_arguments)]
pub fn begin_write_wal_frame(
io: &Arc<dyn File>,
offset: usize,
page: &PageRef,
page_size: u16,
db_size: u32,
write_counter: Rc<RefCell<usize>>,
wal_header: &WalHeader,
checksums: (u32, u32),
) -> Result<(u32, u32)> {
let page_finish = page.clone();
let page_id = page.get().id;
tracing::trace!(page_id);
let mut header = WalFrameHeader {
page_number: page_id as u32,
db_size,
salt_1: wal_header.salt_1,
salt_2: wal_header.salt_2,
checksum_1: 0,
checksum_2: 0,
};
let (buffer, checksums) = {
let page = page.get();
let contents = page.contents.as_ref().unwrap();
let drop_fn = Rc::new(|_buf| {});
let mut buffer = Buffer::allocate(
contents.buffer.borrow().len() + WAL_FRAME_HEADER_SIZE,
drop_fn,
);
let buf = buffer.as_mut_slice();
buf[0..4].copy_from_slice(&header.page_number.to_be_bytes());
buf[4..8].copy_from_slice(&header.db_size.to_be_bytes());
buf[8..12].copy_from_slice(&header.salt_1.to_be_bytes());
buf[12..16].copy_from_slice(&header.salt_2.to_be_bytes());
let contents_buf = contents.as_ptr();
let content_len = contents_buf.len();
buf[WAL_FRAME_HEADER_SIZE..WAL_FRAME_HEADER_SIZE + content_len]
.copy_from_slice(contents_buf);
if content_len < page_size as usize {
buf[WAL_FRAME_HEADER_SIZE + content_len..WAL_FRAME_HEADER_SIZE + page_size as usize]
.fill(0);
}
let expects_be = wal_header.magic & 1;
let use_native_endian = cfg!(target_endian = "big") as u32 == expects_be;
let header_checksum = checksum_wal(&buf[0..8], wal_header, checksums, use_native_endian);
let final_checksum = checksum_wal(
&buf[WAL_FRAME_HEADER_SIZE..WAL_FRAME_HEADER_SIZE + page_size as usize],
wal_header,
header_checksum,
use_native_endian,
);
header.checksum_1 = final_checksum.0;
header.checksum_2 = final_checksum.1;
buf[16..20].copy_from_slice(&header.checksum_1.to_be_bytes());
buf[20..24].copy_from_slice(&header.checksum_2.to_be_bytes());
#[allow(clippy::arc_with_non_send_sync)]
(Arc::new(RefCell::new(buffer)), final_checksum)
};
*write_counter.borrow_mut() += 1;
let write_complete = {
let buf_copy = buffer.clone();
Box::new(move |bytes_written: i32| {
let buf_copy = buf_copy.clone();
let buf_len = buf_copy.borrow().len();
*write_counter.borrow_mut() -= 1;
page_finish.clear_dirty();
if bytes_written < buf_len as i32 {
tracing::error!("wrote({bytes_written}) less than expected({buf_len})");
}
})
};
#[allow(clippy::arc_with_non_send_sync)]
let c = Completion::new(CompletionType::Write(WriteCompletion::new(write_complete)));
io.pwrite(offset, buffer.clone(), c)?;
tracing::trace!("Frame written and synced");
Ok(checksums)
}
pub fn begin_write_wal_header(io: &Arc<dyn File>, header: &WalHeader) -> Result<()> {
let buffer = {
let drop_fn = Rc::new(|_buf| {});
let mut buffer = Buffer::allocate(512, drop_fn);
let buf = buffer.as_mut_slice();
buf[0..4].copy_from_slice(&header.magic.to_be_bytes());
buf[4..8].copy_from_slice(&header.file_format.to_be_bytes());
buf[8..12].copy_from_slice(&header.page_size.to_be_bytes());
buf[12..16].copy_from_slice(&header.checkpoint_seq.to_be_bytes());
buf[16..20].copy_from_slice(&header.salt_1.to_be_bytes());
buf[20..24].copy_from_slice(&header.salt_2.to_be_bytes());
buf[24..28].copy_from_slice(&header.checksum_1.to_be_bytes());
buf[28..32].copy_from_slice(&header.checksum_2.to_be_bytes());
#[allow(clippy::arc_with_non_send_sync)]
Arc::new(RefCell::new(buffer))
};
let write_complete = {
Box::new(move |bytes_written: i32| {
if bytes_written < WAL_HEADER_SIZE as i32 {
tracing::error!(
"wal header wrote({bytes_written}) less than expected({WAL_HEADER_SIZE})"
);
}
})
};
#[allow(clippy::arc_with_non_send_sync)]
let c = Completion::new(CompletionType::Write(WriteCompletion::new(write_complete)));
io.pwrite(0, buffer.clone(), c)?;
Ok(())
}
/// Checks if payload will overflow a cell based on the maximum allowed size.
/// It will return the min size that will be stored in that case,
/// including overflow pointer
/// see e.g. https://github.com/sqlite/sqlite/blob/9591d3fe93936533c8c3b0dc4d025ac999539e11/src/dbstat.c#L371
pub fn payload_overflows(
payload_size: usize,
payload_overflow_threshold_max: usize,
payload_overflow_threshold_min: usize,
usable_size: usize,
) -> (bool, usize) {
if payload_size <= payload_overflow_threshold_max {
return (false, 0);
}
let mut space_left = payload_overflow_threshold_min
+ (payload_size - payload_overflow_threshold_min) % (usable_size - 4);
if space_left > payload_overflow_threshold_max {
space_left = payload_overflow_threshold_min;
}
(true, space_left + 4)
}
/// The checksum is computed by interpreting the input as an even number of unsigned 32-bit integers: x(0) through x(N).
/// The 32-bit integers are big-endian if the magic number in the first 4 bytes of the WAL header is 0x377f0683
/// and the integers are little-endian if the magic number is 0x377f0682.
/// The checksum values are always stored in the frame header in a big-endian format regardless of which byte order is used to compute the checksum.
///
/// The checksum algorithm only works for content which is a multiple of 8 bytes in length.
/// In other words, if the inputs are x(0) through x(N) then N must be odd.
/// The checksum algorithm is as follows:
///
/// s0 = s1 = 0
/// for i from 0 to n-1 step 2:
/// s0 += x(i) + s1;
/// s1 += x(i+1) + s0;
/// endfor
///
/// The outputs s0 and s1 are both weighted checksums using Fibonacci weights in reverse order.
/// (The largest Fibonacci weight occurs on the first element of the sequence being summed.)
/// The s1 value spans all 32-bit integer terms of the sequence whereas s0 omits the final term.
pub fn checksum_wal(
buf: &[u8],
_wal_header: &WalHeader,
input: (u32, u32),
native_endian: bool, // Sqlite interprets big endian as "native"
) -> (u32, u32) {
assert_eq!(buf.len() % 8, 0, "buffer must be a multiple of 8");
let mut s0: u32 = input.0;
let mut s1: u32 = input.1;
let mut i = 0;
if native_endian {
while i < buf.len() {
let v0 = u32::from_ne_bytes(buf[i..i + 4].try_into().unwrap());
let v1 = u32::from_ne_bytes(buf[i + 4..i + 8].try_into().unwrap());
s0 = s0.wrapping_add(v0.wrapping_add(s1));
s1 = s1.wrapping_add(v1.wrapping_add(s0));
i += 8;
}
} else {
while i < buf.len() {
let v0 = u32::from_ne_bytes(buf[i..i + 4].try_into().unwrap()).swap_bytes();
let v1 = u32::from_ne_bytes(buf[i + 4..i + 8].try_into().unwrap()).swap_bytes();
s0 = s0.wrapping_add(v0.wrapping_add(s1));
s1 = s1.wrapping_add(v1.wrapping_add(s0));
i += 8;
}
}
(s0, s1)
}
impl WalHeader {
pub fn as_bytes(&self) -> &[u8] {
unsafe { std::mem::transmute::<&WalHeader, &[u8; size_of::<WalHeader>()]>(self) }
}
}
pub fn read_u32(buf: &[u8], pos: usize) -> u32 {
u32::from_be_bytes([buf[pos], buf[pos + 1], buf[pos + 2], buf[pos + 3]])
}
#[cfg(test)]
mod tests {
use crate::Value;
use super::*;
use rstest::rstest;
#[rstest]
#[case(&[], SerialType::null(), Value::Null)]
#[case(&[255], SerialType::i8(), Value::Integer(-1))]
#[case(&[0x12, 0x34], SerialType::i16(), Value::Integer(0x1234))]
#[case(&[0xFE], SerialType::i8(), Value::Integer(-2))]
#[case(&[0x12, 0x34, 0x56], SerialType::i24(), Value::Integer(0x123456))]
#[case(&[0x12, 0x34, 0x56, 0x78], SerialType::i32(), Value::Integer(0x12345678))]
#[case(&[0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC], SerialType::i48(), Value::Integer(0x123456789ABC))]
#[case(&[0x12, 0x34, 0x56, 0x78, 0x9A, 0xBC, 0xDE, 0xFF], SerialType::i64(), Value::Integer(0x123456789ABCDEFF))]
#[case(&[0x40, 0x09, 0x21, 0xFB, 0x54, 0x44, 0x2D, 0x18], SerialType::f64(), Value::Float(std::f64::consts::PI))]
#[case(&[1, 2], SerialType::const_int0(), Value::Integer(0))]
#[case(&[65, 66], SerialType::const_int1(), Value::Integer(1))]
#[case(&[1, 2, 3], SerialType::blob(3), Value::Blob(vec![1, 2, 3]))]
#[case(&[], SerialType::blob(0), Value::Blob(vec![]))] // empty blob
#[case(&[65, 66, 67], SerialType::text(3), Value::build_text("ABC"))]
#[case(&[0x80], SerialType::i8(), Value::Integer(-128))]
#[case(&[0x80, 0], SerialType::i16(), Value::Integer(-32768))]
#[case(&[0x80, 0, 0], SerialType::i24(), Value::Integer(-8388608))]
#[case(&[0x80, 0, 0, 0], SerialType::i32(), Value::Integer(-2147483648))]
#[case(&[0x80, 0, 0, 0, 0, 0], SerialType::i48(), Value::Integer(-140737488355328))]
#[case(&[0x80, 0, 0, 0, 0, 0, 0, 0], SerialType::i64(), Value::Integer(-9223372036854775808))]
#[case(&[0x7f], SerialType::i8(), Value::Integer(127))]
#[case(&[0x7f, 0xff], SerialType::i16(), Value::Integer(32767))]
#[case(&[0x7f, 0xff, 0xff], SerialType::i24(), Value::Integer(8388607))]
#[case(&[0x7f, 0xff, 0xff, 0xff], SerialType::i32(), Value::Integer(2147483647))]
#[case(&[0x7f, 0xff, 0xff, 0xff, 0xff, 0xff], SerialType::i48(), Value::Integer(140737488355327))]
#[case(&[0x7f, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff], SerialType::i64(), Value::Integer(9223372036854775807))]
fn test_read_value(
#[case] buf: &[u8],
#[case] serial_type: SerialType,
#[case] expected: Value,
) {
let result = read_value(buf, serial_type).unwrap();
assert_eq!(result.0.to_owned(), expected);
}
#[test]
fn test_serial_type_helpers() {
assert_eq!(
TryInto::<SerialType>::try_into(12u64).unwrap(),
SerialType::blob(0)
);
assert_eq!(
TryInto::<SerialType>::try_into(14u64).unwrap(),
SerialType::blob(1)
);
assert_eq!(
TryInto::<SerialType>::try_into(13u64).unwrap(),
SerialType::text(0)
);
assert_eq!(
TryInto::<SerialType>::try_into(15u64).unwrap(),
SerialType::text(1)
);
assert_eq!(
TryInto::<SerialType>::try_into(16u64).unwrap(),
SerialType::blob(2)
);
assert_eq!(
TryInto::<SerialType>::try_into(17u64).unwrap(),
SerialType::text(2)
);
}
#[rstest]
#[case(0, SerialType::null())]
#[case(1, SerialType::i8())]
#[case(2, SerialType::i16())]
#[case(3, SerialType::i24())]
#[case(4, SerialType::i32())]
#[case(5, SerialType::i48())]
#[case(6, SerialType::i64())]
#[case(7, SerialType::f64())]
#[case(8, SerialType::const_int0())]
#[case(9, SerialType::const_int1())]
#[case(12, SerialType::blob(0))]
#[case(13, SerialType::text(0))]
#[case(14, SerialType::blob(1))]
#[case(15, SerialType::text(1))]
fn test_parse_serial_type(#[case] input: u64, #[case] expected: SerialType) {
let result = SerialType::try_from(input).unwrap();
assert_eq!(result, expected);
}
#[test]
fn test_validate_serial_type() {
for i in 0..=9 {
let result = validate_serial_type(i);
assert!(result.is_ok());
}
for i in 10..=11 {
let result = validate_serial_type(i);
assert!(result.is_err());
}
for i in 12..=1000 {
let result = validate_serial_type(i);
assert!(result.is_ok());
}
}
#[test]
fn test_smallvec_iter() {
let mut small_vec = SmallVec::<i32, 4>::new();
(0..8).for_each(|i| small_vec.push(i));
let mut iter = small_vec.iter();
assert_eq!(iter.next(), Some(0));
assert_eq!(iter.next(), Some(1));
assert_eq!(iter.next(), Some(2));
assert_eq!(iter.next(), Some(3));
assert_eq!(iter.next(), Some(4));
assert_eq!(iter.next(), Some(5));
assert_eq!(iter.next(), Some(6));
assert_eq!(iter.next(), Some(7));
assert_eq!(iter.next(), None);
}
#[test]
fn test_smallvec_get() {
let mut small_vec = SmallVec::<i32, 4>::new();
(0..8).for_each(|i| small_vec.push(i));
(0..8).for_each(|i| {
assert_eq!(small_vec.get(i), Some(i as i32));
});
assert_eq!(small_vec.get(8), None);
}
}
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