use std::io::{Seek, SeekFrom, Write};
use crate::error::{Error, Result};
use crate::format::btree_v2::BTreeV2Header;
use crate::format::checksum::checksum_metadata;
use crate::format::fractal_heap::FractalHeapHeader;
use crate::format::messages::attribute::AttributeMessage;
use crate::format::messages::attribute_info::AttributeInfoMessage;
use crate::format::object_header::{
self, HDR_ATTR_STORE_PHASE_CHANGE, HDR_CHUNK0_SIZE_MASK, HDR_STORE_TIMES, HDR_V2_KNOWN_FLAGS,
};
use super::MutableFile;
#[derive(Debug)]
struct CompactAttributeMessageLocation {
msg_type_offset: u64,
msg_data_offset: u64,
oh_start: u64,
oh_check_len: usize,
raw_data: Vec<u8>,
}
#[derive(Debug)]
struct DenseAttributeLocation {
attr_info_addr: u64,
heap: FractalHeapHeader,
btree: BTreeV2Header,
leaf_records: Vec<u8>,
record_index: usize,
direct_block_addr: u64,
direct_block_size: u64,
object_offset: u64,
raw_data: Vec<u8>,
}
impl MutableFile {
pub fn delete_root_attr(&mut self, name: &str) -> Result<()> {
self.delete_attr_at(self.superblock.root_addr, name)
}
pub fn delete_group_attr(&mut self, group_path: &str, name: &str) -> Result<()> {
let group = self.group(group_path)?;
self.delete_attr_at(group.addr(), name)
}
pub fn delete_dataset_attr(&mut self, dataset_path: &str, name: &str) -> Result<()> {
let dataset = self.dataset(dataset_path)?;
self.delete_attr_at(dataset.addr(), name)
}
pub fn rename_root_attr(&mut self, old_name: &str, new_name: &str) -> Result<()> {
self.rename_attr_at(self.superblock.root_addr, old_name, new_name)
}
pub fn rename_group_attr(
&mut self,
group_path: &str,
old_name: &str,
new_name: &str,
) -> Result<()> {
let group = self.group(group_path)?;
self.rename_attr_at(group.addr(), old_name, new_name)
}
pub fn rename_dataset_attr(
&mut self,
dataset_path: &str,
old_name: &str,
new_name: &str,
) -> Result<()> {
let dataset = self.dataset(dataset_path)?;
self.rename_attr_at(dataset.addr(), old_name, new_name)
}
fn delete_attr_at(&mut self, object_addr: u64, name: &str) -> Result<()> {
match self.find_compact_attribute_message_in_oh(object_addr, name) {
Ok(location) => {
self.write_handle
.seek(SeekFrom::Start(location.msg_type_offset))?;
self.write_handle
.write_all(&[object_header::MSG_NIL as u8])?;
self.rewrite_oh_checksum(location.oh_start, location.oh_check_len)?;
}
Err(Error::Unsupported(message)) if message.contains("dense attributes") => {
let location = self.find_dense_attribute_location(object_addr, name, None)?;
self.delete_dense_attribute(location)?;
}
Err(err) => return Err(err),
}
self.write_handle.flush()?;
self.reopen_reader()?;
Ok(())
}
fn rename_attr_at(&mut self, object_addr: u64, old_name: &str, new_name: &str) -> Result<()> {
if new_name.is_empty() {
return Err(Error::InvalidFormat(
"attribute name cannot be empty".into(),
));
}
if old_name == new_name {
return Ok(());
}
match self.find_compact_attribute_rename_location(object_addr, old_name, new_name) {
Ok(mut location) => {
let (name_offset, name_size) =
Self::compact_attribute_name_field(&location.raw_data)?;
if new_name.len() + 1 != name_size {
return Err(Error::Unsupported(
"in-place compact attribute rename cannot grow or shrink the encoded name field"
.into(),
));
}
let name_offset_u64 = Self::usize_to_u64(name_offset, "attribute name offset")?;
let file_name_offset = location
.msg_data_offset
.checked_add(name_offset_u64)
.ok_or_else(|| Error::InvalidFormat("attribute name offset overflow".into()))?;
let encoded_name = encode_attribute_name_in_place(
&mut location.raw_data,
name_offset,
name_size,
new_name,
)?;
self.write_handle.seek(SeekFrom::Start(file_name_offset))?;
self.write_handle.write_all(encoded_name)?;
self.rewrite_oh_checksum(location.oh_start, location.oh_check_len)?;
}
Err(Error::Unsupported(message)) if message.contains("dense attributes") => {
let location =
self.find_dense_attribute_location(object_addr, old_name, Some(new_name))?;
self.rename_dense_attribute(location, new_name)?;
}
Err(err) => return Err(err),
}
self.write_handle.flush()?;
self.reopen_reader()?;
Ok(())
}
fn compact_attribute_name_field(raw: &[u8]) -> Result<(usize, usize)> {
if raw.len() < 4 {
return Err(Error::InvalidFormat("attribute message too short".into()));
}
let version = raw
.first()
.copied()
.ok_or_else(|| Error::InvalidFormat("attribute message too short".into()))?;
let name_size = usize::from(read_u16_le_at(raw, 2, "attribute name size")?);
if name_size == 0 {
return Err(Error::InvalidFormat(
"attribute message name length is zero".into(),
));
}
let offset: usize = match version {
1 | 2 => 8,
3 => 9,
other => Err(Error::InvalidFormat(format!(
"attribute message version {other}"
)))?,
};
let end = offset
.checked_add(name_size)
.ok_or_else(|| Error::InvalidFormat("attribute name field overflow".into()))?;
if end > raw.len() {
return Err(Error::InvalidFormat(
"attribute name field exceeds message".into(),
));
}
Ok((offset, name_size))
}
fn find_compact_attribute_message_in_oh(
&self,
oh_addr: u64,
name: &str,
) -> Result<CompactAttributeMessageLocation> {
self.find_compact_attribute_in_oh(oh_addr, name, None)
}
fn find_compact_attribute_rename_location(
&self,
oh_addr: u64,
old_name: &str,
new_name: &str,
) -> Result<CompactAttributeMessageLocation> {
self.find_compact_attribute_in_oh(oh_addr, old_name, Some(new_name))
}
fn find_compact_attribute_in_oh(
&self,
oh_addr: u64,
target_name: &str,
reject_duplicate_name: Option<&str>,
) -> Result<CompactAttributeMessageLocation> {
let mut guard = self.inner.lock();
let reader = &mut guard.reader;
reader.seek(oh_addr)?;
let mut first_bytes = [0u8; 4];
reader.read_bytes_into(&mut first_bytes)?;
if first_bytes != [b'O', b'H', b'D', b'R'] {
return Err(Error::Unsupported(
"attribute mutation currently supports only v2 object headers".into(),
));
}
let version = reader.read_u8()?;
if version != 2 {
return Err(Error::Unsupported(
"attribute mutation currently supports only v2 object headers".into(),
));
}
let flags = reader.read_u8()?;
if flags & !HDR_V2_KNOWN_FLAGS != 0 {
return Err(Error::InvalidFormat(format!(
"object header v2 flags contain reserved bits: {flags:#04x}"
)));
}
if flags & HDR_STORE_TIMES != 0 {
reader.skip(16)?;
}
if flags & HDR_ATTR_STORE_PHASE_CHANGE != 0 {
reader.skip(4)?;
}
let chunk0_size_bytes = 1u8 << (flags & HDR_CHUNK0_SIZE_MASK);
let chunk0_data_size = reader.read_uint(chunk0_size_bytes)?;
let chunk0_data_start = reader.position()?;
let chunk0_data_end = chunk0_data_start
.checked_add(chunk0_data_size)
.ok_or_else(|| Error::InvalidFormat("object-header chunk range overflow".into()))?;
let oh_check_len = usize::try_from(chunk0_data_end - oh_addr)
.map_err(|_| Error::InvalidFormat("object-header checksum range overflow".into()))?;
let mut has_dense_attrs = false;
let mut found = None;
while reader.position()? < chunk0_data_end {
let msg_header_pos = reader.position()?;
if msg_header_pos
.checked_add(4)
.is_none_or(|end| end > chunk0_data_end)
{
break;
}
let msg_type = u16::from(reader.read_u8()?);
let msg_size = usize::from(reader.read_u16()?);
let _msg_flags = reader.read_u8()?;
if flags & object_header::HDR_ATTR_CRT_ORDER_TRACKED != 0 {
reader.skip(2)?;
}
let msg_data_offset = reader.position()?;
let msg_size_u64 = Self::usize_to_u64(msg_size, "object-header message size")?;
if msg_data_offset
.checked_add(msg_size_u64)
.is_none_or(|end| end > chunk0_data_end)
{
return Err(Error::InvalidFormat(
"object-header message payload exceeds chunk".into(),
));
}
if msg_type == object_header::MSG_ATTRIBUTE {
let mut data = vec![0u8; msg_size];
reader.read_bytes_into(&mut data)?;
let attr = AttributeMessage::decode(&data)?;
if reject_duplicate_name.is_some_and(|name| attr.name == name) {
return Err(Error::InvalidFormat(format!(
"attribute '{}' already exists",
attr.name
)));
}
if attr.name == target_name {
let location = CompactAttributeMessageLocation {
msg_type_offset: msg_header_pos,
msg_data_offset,
oh_start: oh_addr,
oh_check_len,
raw_data: data,
};
if reject_duplicate_name.is_none() {
return Ok(location);
}
found = Some(location);
}
} else {
if msg_type == object_header::MSG_ATTR_INFO {
has_dense_attrs = true;
}
reader.skip(msg_size_u64)?;
}
}
if let Some(location) = found {
return Ok(location);
}
if has_dense_attrs {
Err(Error::Unsupported(
"mutating dense attributes is not implemented".into(),
))
} else {
Err(Error::InvalidFormat(format!(
"attribute '{target_name}' not found"
)))
}
}
fn find_dense_attribute_location(
&self,
object_addr: u64,
target_name: &str,
reject_duplicate_name: Option<&str>,
) -> Result<DenseAttributeLocation> {
let mut guard = self.inner.lock();
let attr_info =
Self::read_dense_attribute_info_message(&mut guard.reader, object_addr, target_name)?;
if !attr_info.has_dense_storage() {
return Err(Error::InvalidFormat(format!(
"attribute '{target_name}' not found"
)));
}
if attr_info.corder_btree_addr.is_some() {
return Err(Error::Unsupported(
"mutating creation-order indexed dense attributes is not implemented".into(),
));
}
let heap = FractalHeapHeader::read_at(&mut guard.reader, attr_info.fractal_heap_addr)?;
if heap.io_filter_len != 0 {
return Err(Error::Unsupported(
"mutating filtered dense attribute heaps is not implemented".into(),
));
}
let btree = BTreeV2Header::read_at(&mut guard.reader, attr_info.name_btree_addr)?;
if btree.tree_type != 8 || btree.depth != 0 {
return Err(Error::Unsupported(
"mutating non-leaf dense attribute name indexes is not implemented".into(),
));
}
let mut leaf_records = Vec::new();
Self::read_dense_attribute_leaf_records_into(&mut guard.reader, &btree, &mut leaf_records)?;
let heap_id_len = usize::from(heap.heap_id_len);
let mut found = None;
let record_size = usize::from(btree.record_size);
for (idx, record) in leaf_records.chunks_exact(record_size).enumerate() {
let heap_id = checked_window(record, 0, heap_id_len, "dense attribute heap ID")?;
let raw_data = heap.read_managed_object(&mut guard.reader, heap_id)?;
let attr = AttributeMessage::decode(&raw_data)?;
if reject_duplicate_name.is_some_and(|name| attr.name == name) {
return Err(Error::InvalidFormat(format!(
"attribute '{}' already exists",
attr.name
)));
}
if attr.name == target_name {
let object_location = heap.managed_object_location(&mut guard.reader, heap_id)?;
found = Some((idx, object_location, raw_data));
}
}
let (record_index, object_location, raw_data) = found
.ok_or_else(|| Error::InvalidFormat(format!("attribute '{target_name}' not found")))?;
Ok(DenseAttributeLocation {
attr_info_addr: attr_info.name_btree_addr,
heap,
btree,
leaf_records,
record_index,
direct_block_addr: object_location.block_addr,
direct_block_size: object_location.block_size,
object_offset: object_location.object_offset,
raw_data,
})
}
fn delete_dense_attribute(&mut self, mut location: DenseAttributeLocation) -> Result<()> {
let record_size = usize::from(location.btree.record_size);
let start = location
.record_index
.checked_mul(record_size)
.ok_or_else(|| Error::InvalidFormat("dense attribute record offset overflow".into()))?;
let end = start
.checked_add(record_size)
.ok_or_else(|| Error::InvalidFormat("dense attribute record offset overflow".into()))?;
if end > location.leaf_records.len() {
return Err(Error::InvalidFormat(
"dense attribute record index is invalid".into(),
));
}
location.leaf_records.copy_within(end.., start);
location
.leaf_records
.truncate(location.leaf_records.len() - record_size);
self.rewrite_dense_attribute_name_index(&location)
}
fn rename_dense_attribute(
&mut self,
mut location: DenseAttributeLocation,
new_name: &str,
) -> Result<()> {
let (name_offset, name_size) = Self::compact_attribute_name_field(&location.raw_data)?;
if new_name.len() + 1 != name_size {
return Err(Error::Unsupported(
"in-place dense attribute rename cannot grow or shrink the encoded name field"
.into(),
));
}
let name_offset_u64 = Self::usize_to_u64(name_offset, "dense attribute name offset")?;
let file_name_offset = location
.direct_block_addr
.checked_add(location.object_offset)
.and_then(|offset| offset.checked_add(name_offset_u64))
.ok_or_else(|| Error::InvalidFormat("dense attribute name offset overflow".into()))?;
self.write_handle.seek(SeekFrom::Start(file_name_offset))?;
{
let encoded_name = encode_attribute_name_in_place(
&mut location.raw_data,
name_offset,
name_size,
new_name,
)?;
self.write_handle.write_all(encoded_name)?;
}
let record_size = usize::from(location.btree.record_size);
let record_start = location
.record_index
.checked_mul(record_size)
.ok_or_else(|| Error::InvalidFormat("dense attribute record offset overflow".into()))?;
let record_end = record_start
.checked_add(record_size)
.ok_or_else(|| Error::InvalidFormat("dense attribute record offset overflow".into()))?;
let record = location
.leaf_records
.get_mut(record_start..record_end)
.ok_or_else(|| {
Error::InvalidFormat("dense attribute record index is invalid".into())
})?;
let hash_pos = dense_attribute_record_hash_pos(&location.heap, record)?;
let hash_end = hash_pos
.checked_add(4)
.ok_or_else(|| Error::InvalidFormat("dense attribute hash offset overflow".into()))?;
record[hash_pos..hash_end].copy_from_slice(&dense_name_hash(new_name).to_le_bytes());
Self::reposition_dense_attribute_record_by_hash(
&location.heap,
&mut location.leaf_records,
location.record_index,
record_size,
)?;
let encoded_name = checked_window(
&location.raw_data,
name_offset,
name_size,
"dense attribute encoded name",
)?;
self.rewrite_dense_attribute_direct_block_checksum(
&location.heap,
location.direct_block_addr,
location.direct_block_size,
file_name_offset,
encoded_name,
)?;
self.rewrite_dense_attribute_name_index(&location)
}
fn rewrite_dense_attribute_name_index(
&mut self,
location: &DenseAttributeLocation,
) -> Result<()> {
let record_size = usize::from(location.btree.record_size);
if record_size == 0 || !location.leaf_records.len().is_multiple_of(record_size) {
return Err(Error::InvalidFormat(
"dense attribute records have inconsistent sizes".into(),
));
}
let record_count = location.leaf_records.len() / record_size;
let record_count_u16 = Self::usize_to_u16(record_count, "dense attribute record count")?;
let record_count_u64 = Self::usize_to_u64(record_count, "dense attribute record count")?;
let mut leaf = Vec::with_capacity(
6usize
.checked_add(location.leaf_records.len())
.and_then(|len| len.checked_add(4))
.ok_or_else(|| Error::InvalidFormat("dense attribute leaf size overflow".into()))?,
);
leaf.extend_from_slice(b"BTLF");
leaf.push(0);
leaf.push(location.btree.tree_type);
leaf.extend_from_slice(&location.leaf_records);
let checksum = checksum_metadata(&leaf);
leaf.extend_from_slice(&checksum.to_le_bytes());
self.write_handle
.seek(SeekFrom::Start(location.btree.root_addr))?;
self.write_handle.write_all(&leaf)?;
let sa = usize::from(self.superblock.sizeof_addr);
let ss = usize::from(self.superblock.sizeof_size);
let header_capacity = 22usize
.checked_add(sa)
.and_then(|len| len.checked_add(ss))
.ok_or_else(|| {
Error::InvalidFormat("dense attribute B-tree header size overflow".into())
})?;
let mut header = Vec::with_capacity(header_capacity);
header.extend_from_slice(b"BTHD");
header.push(0);
header.push(location.btree.tree_type);
header.extend_from_slice(&location.btree.node_size.to_le_bytes());
header.extend_from_slice(&location.btree.record_size.to_le_bytes());
header.extend_from_slice(&0u16.to_le_bytes());
header.push(location.btree.split_pct);
header.push(location.btree.merge_pct);
let mut scratch = [0u8; 8];
header.extend_from_slice(Self::encode_uint_le_into(
location.btree.root_addr,
&mut scratch,
sa,
"dense attribute B-tree root address",
)?);
header.extend_from_slice(&record_count_u16.to_le_bytes());
header.extend_from_slice(Self::encode_uint_le_into(
record_count_u64,
&mut scratch,
ss,
"dense attribute B-tree total record count",
)?);
let checksum = checksum_metadata(&header);
header.extend_from_slice(&checksum.to_le_bytes());
self.write_handle
.seek(SeekFrom::Start(location.attr_info_addr))?;
self.write_handle.write_all(&header)?;
Ok(())
}
fn read_dense_attribute_info_message<R: std::io::Read + Seek>(
reader: &mut crate::io::reader::HdfReader<R>,
oh_addr: u64,
target_name: &str,
) -> Result<AttributeInfoMessage> {
reader.seek(oh_addr)?;
let mut first_bytes = [0u8; 4];
reader.read_bytes_into(&mut first_bytes)?;
if first_bytes != [b'O', b'H', b'D', b'R'] {
return Err(Error::Unsupported(
"attribute mutation currently supports only v2 object headers".into(),
));
}
let version = reader.read_u8()?;
if version != 2 {
return Err(Error::Unsupported(
"attribute mutation currently supports only v2 object headers".into(),
));
}
let flags = reader.read_u8()?;
if flags & !HDR_V2_KNOWN_FLAGS != 0 {
return Err(Error::InvalidFormat(format!(
"object header v2 flags contain reserved bits: {flags:#04x}"
)));
}
if flags & HDR_STORE_TIMES != 0 {
reader.skip(16)?;
}
if flags & HDR_ATTR_STORE_PHASE_CHANGE != 0 {
reader.skip(4)?;
}
let chunk0_size_bytes = 1u8 << (flags & HDR_CHUNK0_SIZE_MASK);
let chunk0_data_size = reader.read_uint(chunk0_size_bytes)?;
let chunk0_data_start = reader.position()?;
let chunk0_data_end = chunk0_data_start
.checked_add(chunk0_data_size)
.ok_or_else(|| Error::InvalidFormat("object-header chunk range overflow".into()))?;
while reader.position()? < chunk0_data_end {
let msg_header_pos = reader.position()?;
if msg_header_pos
.checked_add(4)
.is_none_or(|end| end > chunk0_data_end)
{
break;
}
let msg_type = u16::from(reader.read_u8()?);
let msg_size = usize::from(reader.read_u16()?);
let _msg_flags = reader.read_u8()?;
if flags & object_header::HDR_ATTR_CRT_ORDER_TRACKED != 0 {
reader.skip(2)?;
}
let msg_data_offset = reader.position()?;
let msg_size_u64 = Self::usize_to_u64(msg_size, "object-header message size")?;
if msg_data_offset
.checked_add(msg_size_u64)
.is_none_or(|end| end > chunk0_data_end)
{
return Err(Error::InvalidFormat(
"object-header message payload exceeds chunk".into(),
));
}
if msg_type == object_header::MSG_ATTR_INFO {
let mut data = vec![0u8; msg_size];
reader.read_bytes_into(&mut data)?;
return AttributeInfoMessage::decode(&data, reader.sizeof_addr());
}
reader.skip(msg_size_u64)?;
}
Err(Error::InvalidFormat(format!(
"attribute '{target_name}' not found"
)))
}
fn read_dense_attribute_leaf_records_into<R: std::io::Read + Seek>(
reader: &mut crate::io::reader::HdfReader<R>,
btree: &BTreeV2Header,
records: &mut Vec<u8>,
) -> Result<()> {
let record_size = usize::from(btree.record_size);
let record_count = usize::from(btree.root_nrecords);
let records_len = record_size
.checked_mul(record_count)
.ok_or_else(|| Error::InvalidFormat("dense attribute leaf records overflow".into()))?;
let check_len = 6usize
.checked_add(records_len)
.ok_or_else(|| Error::InvalidFormat("dense attribute leaf size overflow".into()))?;
let total_len = check_len
.checked_add(4)
.ok_or_else(|| Error::InvalidFormat("dense attribute leaf size overflow".into()))?;
records.clear();
records.resize(total_len, 0);
reader.seek(btree.root_addr)?;
reader.read_bytes_into(records)?;
if records.get(..4) != Some(&b"BTLF"[..]) {
return Err(Error::InvalidFormat(
"invalid dense attribute B-tree leaf magic".into(),
));
}
if records.get(4).copied() != Some(0) || records.get(5).copied() != Some(btree.tree_type) {
return Err(Error::InvalidFormat(
"dense attribute B-tree leaf header does not match index".into(),
));
}
let stored = read_u32_le_at(records, check_len, "dense attribute leaf checksum")?;
let computed = checksum_metadata(&records[..check_len]);
if stored != computed {
return Err(Error::InvalidFormat(format!(
"dense attribute leaf checksum mismatch: stored={stored:#010x}, computed={computed:#010x}"
)));
}
records.drain(..6);
records.truncate(records_len);
Ok(())
}
fn reposition_dense_attribute_record_by_hash(
heap: &FractalHeapHeader,
records: &mut [u8],
record_index: usize,
record_size: usize,
) -> Result<()> {
if record_size == 0 || !records.len().is_multiple_of(record_size) {
return Err(Error::InvalidFormat(
"dense attribute records have inconsistent sizes".into(),
));
}
let record_count = records.len() / record_size;
if record_index >= record_count {
return Err(Error::InvalidFormat(
"dense attribute record index is invalid".into(),
));
}
let start = record_index
.checked_mul(record_size)
.ok_or_else(|| Error::InvalidFormat("dense attribute record offset overflow".into()))?;
let end = start
.checked_add(record_size)
.ok_or_else(|| Error::InvalidFormat("dense attribute record offset overflow".into()))?;
let record = records.get(start..end).ok_or_else(|| {
Error::InvalidFormat("dense attribute record index is invalid".into())
})?;
let hash_pos = dense_attribute_record_hash_pos(heap, record)?;
let changed_hash = read_u32_le_at(record, hash_pos, "dense attribute record hash")?;
let mut insert_index = record_count - 1;
let mut logical_idx = 0usize;
for (idx, record) in records.chunks_exact(record_size).enumerate() {
if idx == record_index {
continue;
}
let hash_pos = dense_attribute_record_hash_pos(heap, record)?;
let hash = read_u32_le_at(record, hash_pos, "dense attribute record hash")?;
if changed_hash < hash {
insert_index = logical_idx;
break;
}
logical_idx += 1;
}
if insert_index == record_index {
return Ok(());
}
let insert_pos = insert_index
.checked_mul(record_size)
.ok_or_else(|| Error::InvalidFormat("dense attribute record offset overflow".into()))?;
if insert_index < record_index {
records[insert_pos..end].rotate_right(record_size);
} else {
let rotate_end = insert_pos.checked_add(record_size).ok_or_else(|| {
Error::InvalidFormat("dense attribute record offset overflow".into())
})?;
records[start..rotate_end].rotate_left(record_size);
}
Ok(())
}
fn rewrite_dense_attribute_direct_block_checksum(
&mut self,
heap: &FractalHeapHeader,
block_addr: u64,
block_size: u64,
patched_addr: u64,
patched_data: &[u8],
) -> Result<()> {
if !heap.has_checksum {
return Ok(());
}
let block_size = usize::try_from(block_size)
.map_err(|_| Error::InvalidFormat("dense attribute direct block too large".into()))?;
let checksum_pos = direct_block_checksum_pos(heap, self.superblock.sizeof_addr)?;
let checksum_end = checksum_pos
.checked_add(4)
.ok_or_else(|| Error::InvalidFormat("direct block checksum offset overflow".into()))?;
let mut guard = self.inner.lock();
guard.reader.seek(block_addr)?;
let mut block = vec![0u8; block_size];
guard.reader.read_bytes_into(&mut block)?;
drop(guard);
let patch_start = patched_addr
.checked_sub(block_addr)
.ok_or_else(|| Error::InvalidFormat("direct block patch address underflow".into()))?;
let patch_start = usize::try_from(patch_start)
.map_err(|_| Error::InvalidFormat("direct block patch offset too large".into()))?;
let patch_end = patch_start
.checked_add(patched_data.len())
.ok_or_else(|| Error::InvalidFormat("direct block patch range overflow".into()))?;
block
.get_mut(patch_start..patch_end)
.ok_or_else(|| Error::InvalidFormat("direct block patch exceeds block".into()))?
.copy_from_slice(patched_data);
let checksum_window = block.get_mut(checksum_pos..checksum_end).ok_or_else(|| {
Error::InvalidFormat("direct block checksum field is truncated".into())
})?;
checksum_window.fill(0);
let checksum = checksum_metadata(&block);
let checksum_pos_u64 = Self::usize_to_u64(checksum_pos, "direct block checksum position")?;
self.write_handle.seek(SeekFrom::Start(
block_addr.checked_add(checksum_pos_u64).ok_or_else(|| {
Error::InvalidFormat("direct block checksum address overflow".into())
})?,
))?;
self.write_handle.write_all(&checksum.to_le_bytes())?;
Ok(())
}
}
fn checked_window<'a>(raw: &'a [u8], pos: usize, len: usize, context: &str) -> Result<&'a [u8]> {
let end = pos
.checked_add(len)
.ok_or_else(|| Error::InvalidFormat(format!("{context} offset overflow")))?;
raw.get(pos..end)
.ok_or_else(|| Error::InvalidFormat(format!("{context} is truncated")))
}
fn read_u16_le_at(raw: &[u8], pos: usize, context: &str) -> Result<u16> {
let bytes = checked_window(raw, pos, 2, context)?;
let bytes: [u8; 2] = bytes
.try_into()
.map_err(|_| Error::InvalidFormat(format!("{context} is truncated")))?;
Ok(u16::from_le_bytes(bytes))
}
fn read_u32_le_at(raw: &[u8], pos: usize, context: &str) -> Result<u32> {
let bytes = checked_window(raw, pos, 4, context)?;
let bytes: [u8; 4] = bytes
.try_into()
.map_err(|_| Error::InvalidFormat(format!("{context} is truncated")))?;
Ok(u32::from_le_bytes(bytes))
}
fn encode_attribute_name_in_place<'a>(
raw: &'a mut [u8],
name_offset: usize,
name_size: usize,
name: &str,
) -> Result<&'a [u8]> {
let name_field = raw
.get_mut(
name_offset..name_offset.checked_add(name_size).ok_or_else(|| {
Error::InvalidFormat("attribute name field offset overflow".into())
})?,
)
.ok_or_else(|| Error::InvalidFormat("attribute name field exceeds message".into()))?;
name_field.fill(0);
name_field[..name.len()].copy_from_slice(name.as_bytes());
Ok(name_field)
}
fn direct_block_checksum_pos(heap: &FractalHeapHeader, sizeof_addr: u8) -> Result<usize> {
let offset_bytes = fractal_heap_offset_width(heap)?;
5usize
.checked_add(usize::from(sizeof_addr))
.and_then(|pos| pos.checked_add(offset_bytes))
.ok_or_else(|| Error::InvalidFormat("direct block checksum position overflow".into()))
}
fn fractal_heap_offset_width(heap: &FractalHeapHeader) -> Result<usize> {
let max_heap_size = usize::from(heap.max_heap_size);
let offset_bytes = max_heap_size
.checked_add(7)
.ok_or_else(|| Error::InvalidFormat("dense attribute heap offset width overflow".into()))?
/ 8;
if offset_bytes == 0 || offset_bytes > 8 {
return Err(Error::Unsupported(format!(
"dense attribute heap offset width {offset_bytes} is unsupported"
)));
}
Ok(offset_bytes)
}
fn dense_attribute_record_hash_pos(heap: &FractalHeapHeader, record: &[u8]) -> Result<usize> {
let heap_id_len = usize::from(heap.heap_id_len);
let hash_pos = heap_id_len
.checked_add(1)
.and_then(|pos| pos.checked_add(4))
.ok_or_else(|| Error::InvalidFormat("dense attribute hash position overflow".into()))?;
checked_window(record, hash_pos, 4, "dense attribute record hash")?;
Ok(hash_pos)
}
fn dense_name_hash(name: &str) -> u32 {
crate::format::checksum::checksum_lookup3(name.as_bytes(), 0)
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn checked_window_rejects_offset_overflow() {
let err = checked_window(&[], usize::MAX, 1, "attribute mutation test").unwrap_err();
assert!(
err.to_string()
.contains("attribute mutation test offset overflow"),
"unexpected error: {err}"
);
}
#[test]
fn fractal_heap_offset_width_rejects_invalid_widths() {
let heap = FractalHeapHeader {
heap_addr: 0,
heap_id_len: 0,
io_filter_len: 0,
flags: 0,
max_managed_obj_size: 0,
table_width: 0,
start_block_size: 0,
max_direct_block_size: 0,
max_heap_size: 0,
start_root_rows: 0,
root_block_addr: 0,
current_root_rows: 0,
num_managed_objects: 0,
has_checksum: false,
sizeof_addr: 8,
sizeof_size: 8,
huge_btree_addr: 0,
root_direct_filtered_size: None,
root_direct_filter_mask: 0,
filter_pipeline: None,
};
assert!(fractal_heap_offset_width(&heap).is_err());
let mut heap = heap;
heap.max_heap_size = 65;
assert!(fractal_heap_offset_width(&heap).is_err());
heap.max_heap_size = 64;
assert_eq!(fractal_heap_offset_width(&heap).unwrap(), 8);
}
}