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use super::{try_convert_cid, MaybeResolved, MultipleMatchingLinks, ResolveError};
use crate::pb::{FlatUnixFs, PBLink, ParsingFailed, UnixFsType};
use crate::{InvalidCidInLink, UnexpectedNodeType};
use alloc::borrow::Cow;
use alloc::collections::VecDeque;
use core::convert::TryFrom;
use core::fmt;
use libipld::Cid;
pub struct Cache {
buffer: VecDeque<Cid>,
}
impl From<VecDeque<Cid>> for Cache {
fn from(mut buffer: VecDeque<Cid>) -> Self {
buffer.clear();
Cache { buffer }
}
}
impl fmt::Debug for Cache {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(fmt, "Cache {{ buffer: {} }}", self.buffer.capacity())
}
}
pub struct ShardedLookup<'needle> {
links: VecDeque<Cid>,
needle: Cow<'needle, str>,
}
impl fmt::Debug for ShardedLookup<'_> {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
fmt,
"ShardedLookup {{ links: {}, needle: {:?} }}",
self.links.len(),
self.needle.as_ref(),
)
}
}
impl<'needle> ShardedLookup<'needle> {
pub fn pending_links(&self) -> (&Cid, impl Iterator<Item = &Cid>) {
let mut iter = self.links.iter();
let first = iter.next().expect("Already validated there are links");
(first, iter)
}
pub fn continue_walk(
mut self,
next: &[u8],
cache: &mut Option<Cache>,
) -> Result<MaybeResolved<'needle>, LookupError> {
debug_assert_eq!(Some(self.pending_links().0), self.links.front());
self.links
.pop_front()
.expect("Already validated there are links");
let mut hamt = match FlatUnixFs::try_from(next) {
Ok(hamt) if hamt.data.Type == UnixFsType::HAMTShard => hamt,
Ok(other) => return Err(LookupError::UnexpectedBucketType(other.data.Type.into())),
Err(ParsingFailed::InvalidDagPb(e)) | Err(ParsingFailed::InvalidUnixFs(e, _)) => {
*cache = Some(self.links.into());
return Err(LookupError::Read(Some(e)));
}
Err(ParsingFailed::NoData(_)) => {
*cache = Some(self.links.into());
return Err(LookupError::Read(None));
}
};
Self::check_supported(&mut hamt)?;
let found = Self::partition(
hamt.links.into_iter(),
self.needle.as_ref(),
&mut self.links,
)?;
if let Some(cid) = found {
*cache = Some(self.links.into());
Ok(MaybeResolved::Found(cid))
} else if self.links.is_empty() {
*cache = Some(self.links.into());
Ok(MaybeResolved::NotFound)
} else {
Ok(MaybeResolved::NeedToLoadMore(self))
}
}
pub fn with_owned_needle(self) -> ShardedLookup<'static> {
let ShardedLookup { links, needle } = self;
let needle = Cow::Owned(needle.into_owned());
ShardedLookup { links, needle }
}
pub(crate) fn lookup_or_start(
mut hamt: FlatUnixFs<'_>,
needle: &'needle str,
cache: &mut Option<Cache>,
) -> Result<MaybeResolved<'needle>, LookupError> {
Self::check_supported(&mut hamt)?;
let mut links = cache.take().map(|c| c.buffer).unwrap_or_default();
let found = Self::partition(hamt.links.into_iter(), needle, &mut links)?;
if let Some(cid) = found {
*cache = Some(links.into());
Ok(MaybeResolved::Found(cid))
} else if links.is_empty() {
*cache = Some(links.into());
Ok(MaybeResolved::NotFound)
} else {
Ok(MaybeResolved::NeedToLoadMore(ShardedLookup {
links,
needle: Cow::Borrowed(needle),
}))
}
}
pub(crate) fn check_supported(hamt: &mut FlatUnixFs<'_>) -> Result<(), ShardError> {
assert_eq!(hamt.data.Type, UnixFsType::HAMTShard);
if hamt.data.fanout != Some(256) || hamt.data.hashType != Some(34) {
Err(ShardError::UnsupportedProperties {
hash_type: hamt.data.hashType,
fanout: hamt.data.fanout,
})
} else if hamt.data.filesize.is_some() || !hamt.data.blocksizes.is_empty() {
Err(ShardError::UnexpectedProperties {
filesize: hamt.data.filesize,
blocksizes: core::mem::take(&mut hamt.data.blocksizes),
})
} else {
Ok(())
}
}
fn partition<'a>(
iter: impl Iterator<Item = PBLink<'a>>,
needle: &str,
work: &mut VecDeque<Cid>,
) -> Result<Option<Cid>, PartitioningError> {
let mut found = None;
for (i, link) in iter.enumerate() {
let name = link.Name.as_deref().unwrap_or_default();
if name.len() > 2 && &name[2..] == needle {
if let Some(first) = found.take() {
return Err(MultipleMatchingLinks::from((first, (i, link))).into());
} else {
found = Some((i, try_convert_cid(i, link)?));
}
} else if name.len() == 2 {
let cid = try_convert_cid(i, link)?;
work.push_back(cid);
} else {
}
}
Ok(found.map(|(_, cid)| cid))
}
}
pub(crate) enum PartitioningError {
Multiple(MultipleMatchingLinks),
InvalidCid(InvalidCidInLink),
}
impl From<InvalidCidInLink> for PartitioningError {
fn from(e: InvalidCidInLink) -> PartitioningError {
PartitioningError::InvalidCid(e)
}
}
impl From<MultipleMatchingLinks> for PartitioningError {
fn from(e: MultipleMatchingLinks) -> PartitioningError {
PartitioningError::Multiple(e)
}
}
impl From<PartitioningError> for ResolveError {
fn from(e: PartitioningError) -> ResolveError {
ResolveError::Lookup(LookupError::from(e))
}
}
impl From<PartitioningError> for LookupError {
fn from(e: PartitioningError) -> LookupError {
use PartitioningError::*;
match e {
Multiple(m) => LookupError::Multiple(m),
InvalidCid(e) => LookupError::InvalidCid(e),
}
}
}
#[derive(Debug)]
pub enum ShardError {
UnsupportedProperties {
hash_type: Option<u64>,
fanout: Option<u64>,
},
UnexpectedProperties {
filesize: Option<u64>,
blocksizes: Vec<u64>,
},
}
impl fmt::Display for ShardError {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
use ShardError::*;
match self {
UnsupportedProperties { hash_type, fanout } => write!(
fmt,
"unsupported HAMTShard properties: hash_type={:?}, fanout={:?}",
hash_type, fanout
),
UnexpectedProperties {
filesize,
blocksizes,
} => write!(
fmt,
"unexpected HAMTShard properties: filesize=({:?}), {} blocksizes",
filesize,
blocksizes.len()
),
}
}
}
impl std::error::Error for ShardError {}
#[derive(Debug)]
pub enum LookupError {
Multiple(MultipleMatchingLinks),
InvalidCid(InvalidCidInLink),
UnexpectedBucketType(UnexpectedNodeType),
Shard(ShardError),
Read(Option<quick_protobuf::Error>),
}
impl LookupError {
pub fn into_resolve_error(self) -> ResolveError {
self.into()
}
}
impl From<MultipleMatchingLinks> for LookupError {
fn from(e: MultipleMatchingLinks) -> Self {
LookupError::Multiple(e)
}
}
impl From<InvalidCidInLink> for LookupError {
fn from(e: InvalidCidInLink) -> Self {
LookupError::InvalidCid(e)
}
}
impl From<ShardError> for LookupError {
fn from(e: ShardError) -> Self {
LookupError::Shard(e)
}
}
impl fmt::Display for LookupError {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
use LookupError::*;
match self {
InvalidCid(e) => write!(fmt, "Invalid link: {:?}", e),
Multiple(e) => write!(fmt, "Multiple matching links found: {:?}", e),
UnexpectedBucketType(ut) => write!(fmt, "unexpected type for HAMT bucket: {:?}", ut),
Shard(e) => write!(fmt, "{}", e),
Read(Some(e)) => write!(
fmt,
"failed to parse the block as unixfs or dag-pb node: {}",
e
),
Read(None) => write!(fmt, "HAMTDirectory not found in empty dag-pb node"),
}
}
}
impl std::error::Error for LookupError {
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
use LookupError::*;
match self {
Read(Some(e)) => Some(e),
_ => None,
}
}
}
#[cfg(test)]
mod tests {
use super::{LookupError, MaybeResolved, ShardError, ShardedLookup};
use crate::pb::FlatUnixFs;
use core::convert::TryFrom;
use hex_literal::hex;
const DIR: &[u8] = &hex!("122e0a2212204baf5104fe53d495223f8e2ba95375a31fda6b18e926cb54edd61f30b5f1de6512053641646f6318b535122c0a221220fd9f545068048e647d5d0b275ed171596e0c1c04b8fed09dc13bee7607e75bc7120242391883c00312330a2212208a4a68f6b88594ce373419586c12d24bde2d519ab636b1d2dcc986eb6265b7a3120a43444d616b6566696c65189601122f0a2212201ededc99d23a7ef43a8f17e6dd8b89934993245ef39e18936a37e412e536ed681205463562696e18c5ad030a280805121f200000000020000200000000000000000004000000000000000000000000002822308002");
const FILE: &[u8] = &hex!("0a130802120d666f6f6261720a666f6f626172180d");
#[test]
fn direct_hit() {
let parsed = FlatUnixFs::try_from(DIR).unwrap();
let found = ShardedLookup::lookup_or_start(parsed, "bin", &mut None);
match found {
Ok(MaybeResolved::Found(cid))
if cid.to_string() == "QmQRA3JX9JNSccQpXjuKzMVCpfTaP4XpHbrrefqaQFWf5Z" => {}
x => unreachable!("{:?}", x),
}
}
#[test]
fn found_in_the_other_bucket() {
let parsed = FlatUnixFs::try_from(DIR).unwrap();
let see_next = ShardedLookup::lookup_or_start(parsed, "formal", &mut None);
let next = match see_next {
Ok(MaybeResolved::NeedToLoadMore(next)) => next,
x => unreachable!("{:?}", x),
};
{
let (first, mut rest) = next.pending_links();
assert_eq!(
first.to_string(),
"QmfQgmYMYmGQP4X6V3JhTELkQmGVP9kpJgv9duejQ8vWez"
);
assert!(rest.next().is_none());
}
let err = next.continue_walk(FILE, &mut None).unwrap_err();
match err {
LookupError::UnexpectedBucketType(ut) if ut.is_file() => {}
x => unreachable!("{:?}", x),
}
}
#[test]
fn unsupported_hash_type_or_fanout() {
use crate::pb::{FlatUnixFs, UnixFs, UnixFsType};
use alloc::borrow::Cow;
let example = FlatUnixFs {
data: UnixFs {
Type: UnixFsType::HAMTShard,
Data: Some(Cow::Borrowed(
b"this cannot be interpreted yet but would be an error",
)),
filesize: None,
blocksizes: Vec::new(),
hashType: Some(33), fanout: Some(255), mode: None, mtime: None,
},
links: Vec::new(),
};
let err = ShardedLookup::lookup_or_start(example, "doesnt matter", &mut None).unwrap_err();
assert!(
matches!(
err,
LookupError::Shard(ShardError::UnsupportedProperties { .. })
),
"{:?}",
err
);
}
#[test]
fn unexpected_properties() {
use crate::pb::{FlatUnixFs, UnixFs, UnixFsType};
use alloc::borrow::Cow;
let example = FlatUnixFs {
data: UnixFs {
Type: UnixFsType::HAMTShard,
Data: Some(Cow::Borrowed(
b"this cannot be interpreted yet but would be an error",
)),
filesize: Some(1), blocksizes: vec![1], hashType: Some(34),
fanout: Some(256),
mode: None,
mtime: None,
},
links: Vec::new(),
};
let err = ShardedLookup::lookup_or_start(example, "doesnt matter", &mut None).unwrap_err();
assert!(
matches!(
err,
LookupError::Shard(ShardError::UnexpectedProperties { .. })
),
"{:?}",
err
);
}
}