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use anyhow::Result;
use iroh_blobs::Hash;
use super::{
bounds::{ByKeyBounds, RecordsBounds},
ranges::{RecordsByKeyRange, RecordsRange},
RecordsValue,
};
use crate::{
store::{
fs::tables::ReadOnlyTables,
util::{IndexKind, LatestPerKeySelector, SelectorRes},
AuthorFilter, KeyFilter, Query,
},
AuthorId, NamespaceId, SignedEntry,
};
/// A query iterator for entry queries.
#[derive(Debug)]
pub struct QueryIterator {
range: QueryRange,
query: Query,
offset: u64,
count: u64,
}
#[derive(Debug)]
#[allow(clippy::large_enum_variant)]
enum QueryRange {
AuthorKey {
range: RecordsRange<'static>,
key_filter: KeyFilter,
},
KeyAuthor {
range: RecordsByKeyRange,
author_filter: AuthorFilter,
selector: Option<LatestPerKeySelector>,
},
}
impl QueryIterator {
pub fn new(tables: ReadOnlyTables, namespace: NamespaceId, query: Query) -> Result<Self> {
let index_kind = IndexKind::from(&query);
let range = match index_kind {
IndexKind::AuthorKey { range, key_filter } => {
let (bounds, filter) = match range {
// single author: both author and key are selected via the range. therefore
// set `filter` to `Any`.
AuthorFilter::Exact(author) => (
RecordsBounds::author_key(namespace, author, key_filter),
KeyFilter::Any,
),
// no author set => full table scan with the provided key filter
AuthorFilter::Any => (RecordsBounds::namespace(namespace), key_filter),
};
let range = RecordsRange::with_bounds_static(&tables.records, bounds)?;
QueryRange::AuthorKey {
range,
key_filter: filter,
}
}
IndexKind::KeyAuthor {
range,
author_filter,
latest_per_key,
} => {
let bounds = ByKeyBounds::new(namespace, &range);
let range =
RecordsByKeyRange::with_bounds(tables.records_by_key, tables.records, bounds)?;
let selector = latest_per_key.then(LatestPerKeySelector::default);
QueryRange::KeyAuthor {
author_filter,
range,
selector,
}
}
};
Ok(Self {
range,
query,
offset: 0,
count: 0,
})
}
}
impl Iterator for QueryIterator {
type Item = Result<SignedEntry>;
fn next(&mut self) -> Option<Result<SignedEntry>> {
// early-return if we reached the query limit.
if let Some(limit) = self.query.limit() {
if self.count >= limit {
return None;
}
}
loop {
let next = match &mut self.range {
QueryRange::AuthorKey { range, key_filter } => {
// get the next entry from the query range, filtered by the key and empty filters
range.next_filtered(&self.query.sort_direction, |(_ns, _author, key), value| {
key_filter.matches(key)
&& (self.query.include_empty || !value_is_empty(&value))
})
}
QueryRange::KeyAuthor {
range,
author_filter,
selector,
} => loop {
// get the next entry from the query range, filtered by the author filter
let next = range
.next_filtered(&self.query.sort_direction, |(_ns, _key, author)| {
author_filter.matches(&(AuthorId::from(author)))
});
// early-break if next contains Err
let next = match next.transpose() {
Err(err) => break Some(Err(err)),
Ok(next) => next,
};
// push the entry into the selector. if active, only the latest entry
// for each key will be emitted.
let next = match selector {
None => next,
Some(selector) => match selector.push(next) {
SelectorRes::Continue => continue,
SelectorRes::Finished => None,
SelectorRes::Some(res) => Some(res),
},
};
// skip the entry if empty and no empty entries requested
if !self.query.include_empty && matches!(&next, Some(e) if e.is_empty()) {
continue;
}
break next.map(Result::Ok);
},
};
// skip the entry if we didn't get past the requested offset yet.
if self.offset < self.query.offset() && matches!(next, Some(Ok(_))) {
self.offset += 1;
continue;
}
self.count += 1;
return next;
}
}
}
fn value_is_empty(value: &RecordsValue) -> bool {
let (_timestamp, _namespace_sig, _author_sig, _len, hash) = value;
*hash == Hash::EMPTY.as_bytes()
}