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core: simplify page buffer handling

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This commit is contained in:
Pere Díaz
2024-08-25 12:48:37 +02:00
parent 84ed081f19
commit 19f000238c
2 changed files with 43 additions and 70 deletions
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42
core/storage/btree.rs
View File

@@ -420,8 +420,7 @@ impl BTreeCursor {
fn insert_into_cell(&mut self, page: &mut PageContent, payload: &Vec<u8>, cell_idx: usize) {
// TODO: insert into cell payload in internal page
let pc = self.allocate_cell_space(page, payload.len() as u16);
let mut buf_ref = RefCell::borrow_mut(&page.buffer);
let buf: &mut [u8] = buf_ref.as_mut_slice();
let buf = page.as_ptr();
// copy data
buf[pc as usize..pc as usize + payload.len()].copy_from_slice(payload);
@@ -499,10 +498,8 @@ impl BTreeCursor {
{
// move data from one buffer to another
// done in a separate block to satisfy borrow checker
let mut left_buf = RefCell::borrow_mut(&page.buffer);
let left_buf: &mut [u8] = left_buf.as_mut_slice();
let mut right_buf = RefCell::borrow_mut(&right_page.buffer);
let right_buf: &mut [u8] = right_buf.as_mut_slice();
let left_buf: &mut [u8] = page.as_ptr();
let right_buf: &mut [u8] = right_page.as_ptr();
let mut rbrk = right_page.cell_content_area() as usize;
@@ -510,7 +507,7 @@ impl BTreeCursor {
let (mut cell_pointer_idx, _) = page.cell_get_raw_pointer_region();
// move half of cells to right page
for cell_idx in cells_to_move..page.cell_count() {
let (start, len) = page.cell_get_raw_region_borrowed(cell_idx, left_buf);
let (start, len) = page.cell_get_raw_region(cell_idx);
// copy data
rbrk -= len;
right_buf[rbrk..rbrk + len].copy_from_slice(&left_buf[start..start + len]);
@@ -677,8 +674,7 @@ impl BTreeCursor {
if gap + 2 + amount > top {
// defragment
self.defragment_page(page_ref, RefCell::borrow(&self.database_header));
let mut buf_ref = RefCell::borrow_mut(&page_ref.buffer);
let buf = buf_ref.as_mut_slice();
let buf = page_ref.as_ptr();
top = u16::from_be_bytes([buf[5], buf[6]]) as usize;
}
@@ -686,8 +682,7 @@ impl BTreeCursor {
top -= amount;
{
let mut buf_ref = RefCell::borrow_mut(&page_ref.buffer);
let buf = buf_ref.as_mut_slice();
let buf = page_ref.as_ptr();
buf[5..7].copy_from_slice(&(top as u16).to_be_bytes());
}
@@ -711,16 +706,14 @@ impl BTreeCursor {
if cloned_page.cell_count() > 0 {
let page_type = page.page_type();
let buf = RefCell::borrow(&cloned_page.buffer);
let buf = buf.as_slice();
let mut write_buf = RefCell::borrow_mut(&page.buffer);
let write_buf = write_buf.as_mut_slice();
let read_buf = cloned_page.as_ptr();
let write_buf = page.as_ptr();
for i in 0..cloned_page.cell_count() {
let cell_offset = page.offset + 8;
let cell_idx = cell_offset + i * 2;
let pc = u16::from_be_bytes([buf[cell_idx], buf[cell_idx + 1]]) as u64;
let pc = u16::from_be_bytes([read_buf[cell_idx], read_buf[cell_idx + 1]]) as u64;
if pc > last_cell {
unimplemented!("corrupted page");
}
@@ -729,7 +722,7 @@ impl BTreeCursor {
let size = match page_type {
PageType::TableInterior => {
let (_, nr_key) = match read_varint(&buf[pc as usize ..]) {
let (_, nr_key) = match read_varint(&read_buf[pc as usize ..]) {
Ok(v) => v,
Err(_) => todo!(
"error while parsing varint from cell, probably treat this as corruption?"
@@ -738,13 +731,13 @@ impl BTreeCursor {
4 + nr_key as u64
}
PageType::TableLeaf => {
let (payload_size, nr_payload) = match read_varint(&buf[pc as usize..]) {
let (payload_size, nr_payload) = match read_varint(&read_buf[pc as usize..]) {
Ok(v) => v,
Err(_) => todo!(
"error while parsing varint from cell, probably treat this as corruption?"
),
};
let (_, nr_key) = match read_varint(&buf[pc as usize + nr_payload..]) {
let (_, nr_key) = match read_varint(&read_buf[pc as usize + nr_payload..]) {
Ok(v) => v,
Err(_) => todo!(
"error while parsing varint from cell, probably treat this as corruption?"
@@ -765,7 +758,7 @@ impl BTreeCursor {
write_buf[cell_idx..cell_idx + 2].copy_from_slice(&(cbrk as u16).to_be_bytes());
// copy payload
write_buf[cbrk as usize..cbrk as usize + size as usize]
.copy_from_slice(&buf[pc as usize..pc as usize + size as usize]);
.copy_from_slice(&read_buf[pc as usize..pc as usize + size as usize]);
}
}
@@ -774,8 +767,7 @@ impl BTreeCursor {
// return SQLITE_CORRUPT_PAGE(pPage);
// }
assert!(cbrk >= first_cell as u64);
let mut write_buf = RefCell::borrow_mut(&page.buffer);
let write_buf = write_buf.as_mut_slice();
let write_buf = page.as_ptr();
// set new first byte of cell content
write_buf[5..7].copy_from_slice(&(cbrk as u16).to_be_bytes());
@@ -791,8 +783,7 @@ impl BTreeCursor {
// Free blocks can be zero, meaning the "real free space" that can be used to allocate is expected to be between first cell byte
// and end of cell pointer area.
fn compute_free_space(&self, page: &PageContent, db_header: Ref<DatabaseHeader>) -> u16 {
let buffer = RefCell::borrow(&page.buffer);
let buf = buffer.as_slice();
let buf = page.as_ptr();
let usable_space = (db_header.page_size - db_header.unused_space as u16) as usize;
let mut first_byte_in_cell_content = page.cell_content_area();
@@ -852,8 +843,7 @@ fn find_free_cell(page_ref: &PageContent, db_header: Ref<DatabaseHeader>, amount
// unuse_space is reserved bytes at the end of page, therefore we must substract from maxpc
let mut pc = page_ref.first_freeblock() as usize;
let buf_ref = RefCell::borrow(&page_ref.buffer);
let buf = buf_ref.as_slice();
let buf = page_ref.as_ptr();
let usable_space = (db_header.page_size - db_header.unused_space as u16) as usize;
let maxpc = usable_space - amount;

71
core/storage/sqlite3_ondisk.rs
View File

@@ -280,58 +280,48 @@ impl PageContent {
self.read_u8(self.offset).try_into().unwrap()
}
fn read_u8(&self, pos: usize) -> u8 {
// unsafe trick to borrow twice
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_ref().unwrap().as_slice();
buf[pos]
let buf = (*buf_pointer).as_mut().unwrap().as_mut_slice();
buf
}
}
fn read_u8(&self, pos: usize) -> u8 {
let buf = self.as_ptr();
buf[pos]
}
fn read_u16(&self, pos: usize) -> u16 {
unsafe {
let buf_pointer = &self.buffer.as_ptr();
let buf = (*buf_pointer).as_ref().unwrap().as_slice();
u16::from_be_bytes([buf[self.offset + pos], buf[self.offset + pos + 1]])
}
let buf = self.as_ptr();
u16::from_be_bytes([buf[self.offset + pos], buf[self.offset + pos + 1]])
}
fn read_u32(&self, pos: usize) -> u32 {
unsafe {
let buf_pointer = &self.buffer.as_ptr();
let buf = (*buf_pointer).as_ref().unwrap().as_slice();
u32::from_be_bytes([
buf[self.offset + pos],
buf[self.offset + pos + 1],
buf[self.offset + pos + 2],
buf[self.offset + pos + 3],
])
}
let buf = self.as_ptr();
u32::from_be_bytes([
buf[self.offset + pos],
buf[self.offset + pos + 1],
buf[self.offset + pos + 2],
buf[self.offset + pos + 3],
])
}
pub fn write_u8(&self, pos: usize, value: u8) {
unsafe {
let buf_pointer = &self.buffer.as_ptr();
let buf = (*buf_pointer).as_mut().unwrap().as_mut_slice();
buf[self.offset + pos] = value;
}
let buf = self.as_ptr();
buf[self.offset + pos] = value;
}
pub fn write_u16(&self, pos: usize, value: u16) {
unsafe {
let buf_pointer = &self.buffer.as_ptr();
let buf = (*buf_pointer).as_mut().unwrap().as_mut_slice();
buf[self.offset + pos..self.offset + pos + 2].copy_from_slice(&value.to_be_bytes());
}
let buf = self.as_ptr();
buf[self.offset + pos..self.offset + pos + 2].copy_from_slice(&value.to_be_bytes());
}
pub fn write_u32(&self, pos: usize, value: u32) {
unsafe {
let buf_pointer = &self.buffer.as_ptr();
let buf = (*buf_pointer).as_mut().unwrap().as_mut_slice();
buf[self.offset + pos..self.offset + pos + 4].copy_from_slice(&value.to_be_bytes());
}
let buf = self.as_ptr();
buf[self.offset + pos..self.offset + pos + 4].copy_from_slice(&value.to_be_bytes());
}
pub fn first_freeblock(&self) -> u16 {
@@ -360,8 +350,7 @@ impl PageContent {
}
pub fn cell_get(&self, idx: usize) -> Result<BTreeCell> {
let buf = self.buffer.borrow();
let buf = buf.as_slice();
let buf = self.as_ptr();
let ncells = self.cell_count();
let cell_start = match self.page_type() {
@@ -388,12 +377,7 @@ impl PageContent {
}
pub fn cell_get_raw_region(&self, idx: usize) -> (usize, usize) {
let mut buf = self.buffer.borrow_mut();
let buf = buf.as_mut_slice();
self.cell_get_raw_region_borrowed(idx, buf)
}
pub fn cell_get_raw_region_borrowed(&self, idx: usize, buf: &mut [u8]) -> (usize, usize) {
let buf = self.as_ptr();
let ncells = self.cell_count();
let cell_start = match self.page_type() {
PageType::IndexInterior => 12,
@@ -438,8 +422,7 @@ impl PageContent {
}
pub fn write_database_header(&self, header: &DatabaseHeader) {
let mut buf = self.buffer.borrow_mut();
let buf = buf.as_mut_slice();
let buf = self.as_ptr();
write_header_to_buf(buf, header);
}
}