Files
tantivy/src/termdict/mod.rs
2020-04-27 11:56:49 +09:00

477 lines
17 KiB
Rust

/*!
The term dictionary main role is to associate the sorted [`Term`s](../struct.Term.html) to
a [`TermInfo`](../postings/struct.TermInfo.html) struct that contains some meta-information
about the term.
Internally, the term dictionary relies on the `fst` crate to store
a sorted mapping that associate each term to its rank in the lexicographical order.
For instance, in a dictionary containing the sorted terms "abba", "bjork", "blur" and "donovan",
the `TermOrdinal` are respectively `0`, `1`, `2`, and `3`.
For `u64`-terms, tantivy explicitely uses a `BigEndian` representation to ensure that the
lexicographical order matches the natural order of integers.
`i64`-terms are transformed to `u64` using a continuous mapping `val ⟶ val - i64::min_value()`
and then treated as a `u64`.
`f64`-terms are transformed to `u64` using a mapping that preserve order, and are then treated
as `u64`.
A second datastructure makes it possible to access a [`TermInfo`](../postings/struct.TermInfo.html).
*/
/// Position of the term in the sorted list of terms.
pub type TermOrdinal = u64;
mod merger;
mod streamer;
mod term_info_store;
mod termdict;
pub use self::merger::TermMerger;
pub use self::streamer::{TermStreamer, TermStreamerBuilder};
pub use self::termdict::{TermDictionary, TermDictionaryBuilder};
#[cfg(test)]
mod tests {
use super::{TermDictionary, TermDictionaryBuilder, TermStreamer};
use crate::core::Index;
use crate::directory::{Directory, RAMDirectory, ReadOnlySource};
use crate::postings::TermInfo;
use crate::schema::{Document, Schema, TEXT};
use std::path::PathBuf;
use std::str;
const BLOCK_SIZE: usize = 1_500;
fn make_term_info(val: u64) -> TermInfo {
TermInfo {
doc_freq: val as u32,
positions_idx: val * 2u64,
postings_offset: val * 3u64,
}
}
#[test]
fn test_empty_term_dictionary() {
let empty = TermDictionary::empty();
assert!(empty.stream().next().is_none());
}
#[test]
fn test_term_ordinals() {
const COUNTRIES: [&'static str; 7] = [
"San Marino",
"Serbia",
"Slovakia",
"Slovenia",
"Spain",
"Sweden",
"Switzerland",
];
let mut directory = RAMDirectory::create();
let path = PathBuf::from("TermDictionary");
{
let write = directory.open_write(&path).unwrap();
let mut term_dictionary_builder = TermDictionaryBuilder::create(write).unwrap();
for term in COUNTRIES.iter() {
term_dictionary_builder
.insert(term.as_bytes(), &make_term_info(0u64))
.unwrap();
}
term_dictionary_builder.finish().unwrap();
}
let source = directory.open_read(&path).unwrap();
let term_dict: TermDictionary = TermDictionary::from_source(&source);
for (term_ord, term) in COUNTRIES.iter().enumerate() {
assert_eq!(term_dict.term_ord(term).unwrap(), term_ord as u64);
let mut bytes = vec![];
assert!(term_dict.ord_to_term(term_ord as u64, &mut bytes));
assert_eq!(bytes, term.as_bytes());
}
}
#[test]
fn test_term_dictionary_simple() {
let mut directory = RAMDirectory::create();
let path = PathBuf::from("TermDictionary");
{
let write = directory.open_write(&path).unwrap();
let mut term_dictionary_builder = TermDictionaryBuilder::create(write).unwrap();
term_dictionary_builder
.insert("abc".as_bytes(), &make_term_info(34u64))
.unwrap();
term_dictionary_builder
.insert("abcd".as_bytes(), &make_term_info(346u64))
.unwrap();
term_dictionary_builder.finish().unwrap();
}
let source = directory.open_read(&path).unwrap();
let term_dict: TermDictionary = TermDictionary::from_source(&source);
assert_eq!(term_dict.get("abc").unwrap().doc_freq, 34u32);
assert_eq!(term_dict.get("abcd").unwrap().doc_freq, 346u32);
let mut stream = term_dict.stream();
{
{
let (k, v) = stream.next().unwrap();
assert_eq!(k.as_ref(), "abc".as_bytes());
assert_eq!(v.doc_freq, 34u32);
}
assert_eq!(stream.key(), "abc".as_bytes());
assert_eq!(stream.value().doc_freq, 34u32);
}
{
{
let (k, v) = stream.next().unwrap();
assert_eq!(k, "abcd".as_bytes());
assert_eq!(v.doc_freq, 346u32);
}
assert_eq!(stream.key(), "abcd".as_bytes());
assert_eq!(stream.value().doc_freq, 346u32);
}
assert!(!stream.advance());
}
#[test]
fn test_term_iterator() {
let mut schema_builder = Schema::builder();
let text_field = schema_builder.add_text_field("text", TEXT);
let index = Index::create_in_ram(schema_builder.build());
{
let mut index_writer = index.writer_with_num_threads(1, 3_000_000).unwrap();
{
{
let mut doc = Document::default();
doc.add_text(text_field, "a b d f");
index_writer.add_document(doc);
}
index_writer.commit().unwrap();
}
{
{
let mut doc = Document::default();
doc.add_text(text_field, "a b c d f");
index_writer.add_document(doc);
}
index_writer.commit().unwrap();
}
{
{
let mut doc = Document::default();
doc.add_text(text_field, "e f");
index_writer.add_document(doc);
}
index_writer.commit().unwrap();
}
}
let searcher = index.reader().unwrap().searcher();
let field_searcher = searcher.field(text_field);
let mut term_it = field_searcher.terms();
let mut term_string = String::new();
while term_it.advance() {
//let term = Term::from_bytes(term_it.key());
term_string.push_str(str::from_utf8(term_it.key()).expect("test"));
}
assert_eq!(&*term_string, "abcdef");
}
#[test]
fn test_term_dictionary_stream() {
let ids: Vec<_> = (0u32..10_000u32)
.map(|i| (format!("doc{:0>6}", i), i))
.collect();
let buffer: Vec<u8> = {
let mut term_dictionary_builder = TermDictionaryBuilder::create(vec![]).unwrap();
for &(ref id, ref i) in &ids {
term_dictionary_builder
.insert(id.as_bytes(), &make_term_info(*i as u64))
.unwrap();
}
term_dictionary_builder.finish().unwrap()
};
let source = ReadOnlySource::from(buffer);
let term_dictionary: TermDictionary = TermDictionary::from_source(&source);
{
let mut streamer = term_dictionary.stream();
let mut i = 0;
while let Some((streamer_k, streamer_v)) = streamer.next() {
let &(ref key, ref v) = &ids[i];
assert_eq!(streamer_k.as_ref(), key.as_bytes());
assert_eq!(streamer_v, &make_term_info(*v as u64));
i += 1;
}
}
let &(ref key, ref _v) = &ids[2047];
term_dictionary.get(key.as_bytes());
}
#[test]
fn test_stream_high_range_prefix_suffix() {
let buffer: Vec<u8> = {
let mut term_dictionary_builder = TermDictionaryBuilder::create(vec![]).unwrap();
// term requires more than 16bits
term_dictionary_builder
.insert("abcdefghijklmnopqrstuvwxy", &make_term_info(1))
.unwrap();
term_dictionary_builder
.insert("abcdefghijklmnopqrstuvwxyz", &make_term_info(2))
.unwrap();
term_dictionary_builder
.insert("abr", &make_term_info(2))
.unwrap();
term_dictionary_builder.finish().unwrap()
};
let source = ReadOnlySource::from(buffer);
let term_dictionary: TermDictionary = TermDictionary::from_source(&source);
let mut kv_stream = term_dictionary.stream();
assert!(kv_stream.advance());
assert_eq!(kv_stream.key(), "abcdefghijklmnopqrstuvwxy".as_bytes());
assert_eq!(kv_stream.value(), &make_term_info(1));
assert!(kv_stream.advance());
assert_eq!(kv_stream.key(), "abcdefghijklmnopqrstuvwxyz".as_bytes());
assert_eq!(kv_stream.value(), &make_term_info(2));
assert!(kv_stream.advance());
assert_eq!(kv_stream.key(), "abr".as_bytes());
assert!(!kv_stream.advance());
}
#[test]
fn test_stream_range() {
let ids: Vec<_> = (0u32..10_000u32)
.map(|i| (format!("doc{:0>6}", i), i))
.collect();
let buffer: Vec<u8> = {
let mut term_dictionary_builder = TermDictionaryBuilder::create(vec![]).unwrap();
for &(ref id, ref i) in &ids {
term_dictionary_builder
.insert(id.as_bytes(), &make_term_info(*i as u64))
.unwrap();
}
term_dictionary_builder.finish().unwrap()
};
let source = ReadOnlySource::from(buffer);
let term_dictionary: TermDictionary = TermDictionary::from_source(&source);
{
for i in (0..20).chain(6000..8_000) {
let &(ref target_key, _) = &ids[i];
let mut streamer = term_dictionary
.range()
.ge(target_key.as_bytes())
.into_stream();
for j in 0..3 {
let (streamer_k, streamer_v) = streamer.next().unwrap();
let &(ref key, ref v) = &ids[i + j];
assert_eq!(str::from_utf8(streamer_k.as_ref()).unwrap(), key);
assert_eq!(streamer_v.doc_freq, *v);
assert_eq!(streamer_v, &make_term_info(*v as u64));
}
}
}
{
for i in (0..20).chain(BLOCK_SIZE - 10..BLOCK_SIZE + 10) {
let &(ref target_key, _) = &ids[i];
let mut streamer = term_dictionary
.range()
.gt(target_key.as_bytes())
.into_stream();
for j in 0..3 {
let (streamer_k, streamer_v) = streamer.next().unwrap();
let &(ref key, ref v) = &ids[i + j + 1];
assert_eq!(streamer_k.as_ref(), key.as_bytes());
assert_eq!(streamer_v.doc_freq, *v);
}
}
}
{
for i in (0..20).chain(BLOCK_SIZE - 10..BLOCK_SIZE + 10) {
for j in 0..3 {
let &(ref fst_key, _) = &ids[i];
let &(ref last_key, _) = &ids[i + j];
let mut streamer = term_dictionary
.range()
.ge(fst_key.as_bytes())
.lt(last_key.as_bytes())
.into_stream();
for _ in 0..j {
assert!(streamer.next().is_some());
}
assert!(streamer.next().is_none());
}
}
}
}
#[test]
fn test_empty_string() {
let buffer: Vec<u8> = {
let mut term_dictionary_builder = TermDictionaryBuilder::create(vec![]).unwrap();
term_dictionary_builder
.insert(&[], &make_term_info(1 as u64))
.unwrap();
term_dictionary_builder
.insert(&[1u8], &make_term_info(2 as u64))
.unwrap();
term_dictionary_builder.finish().unwrap()
};
let source = ReadOnlySource::from(buffer);
let term_dictionary: TermDictionary = TermDictionary::from_source(&source);
let mut stream = term_dictionary.stream();
assert!(stream.advance());
assert!(stream.key().is_empty());
assert!(stream.advance());
assert_eq!(stream.key(), &[1u8]);
assert!(!stream.advance());
}
#[test]
fn test_stream_range_boundaries() {
let buffer: Vec<u8> = {
let mut term_dictionary_builder = TermDictionaryBuilder::create(vec![]).unwrap();
for i in 0u8..10u8 {
let number_arr = [i; 1];
term_dictionary_builder
.insert(&number_arr, &make_term_info(i as u64))
.unwrap();
}
term_dictionary_builder.finish().unwrap()
};
let source = ReadOnlySource::from(buffer);
let term_dictionary: TermDictionary = TermDictionary::from_source(&source);
let value_list = |mut streamer: TermStreamer<'_>, backwards: bool| {
let mut res: Vec<u32> = vec![];
while let Some((_, ref v)) = streamer.next() {
res.push(v.doc_freq);
}
if backwards {
res.reverse();
}
res
};
{
let range = term_dictionary.range().backward().into_stream();
assert_eq!(
value_list(range, true),
vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
);
}
{
let range = term_dictionary.range().ge([2u8]).into_stream();
assert_eq!(
value_list(range, false),
vec![2u32, 3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
);
}
{
let range = term_dictionary.range().ge([2u8]).backward().into_stream();
assert_eq!(
value_list(range, true),
vec![2u32, 3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
);
}
{
let range = term_dictionary.range().gt([2u8]).into_stream();
assert_eq!(
value_list(range, false),
vec![3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
);
}
{
let range = term_dictionary.range().gt([2u8]).backward().into_stream();
assert_eq!(
value_list(range, true),
vec![3u32, 4u32, 5u32, 6u32, 7u32, 8u32, 9u32]
);
}
{
let range = term_dictionary.range().lt([6u8]).into_stream();
assert_eq!(
value_list(range, false),
vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32]
);
}
{
let range = term_dictionary.range().lt([6u8]).backward().into_stream();
assert_eq!(
value_list(range, true),
vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32]
);
}
{
let range = term_dictionary.range().le([6u8]).into_stream();
assert_eq!(
value_list(range, false),
vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32, 6u32]
);
}
{
let range = term_dictionary.range().le([6u8]).backward().into_stream();
assert_eq!(
value_list(range, true),
vec![0u32, 1u32, 2u32, 3u32, 4u32, 5u32, 6u32]
);
}
{
let range = term_dictionary.range().ge([0u8]).lt([5u8]).into_stream();
assert_eq!(value_list(range, false), vec![0u32, 1u32, 2u32, 3u32, 4u32]);
}
{
let range = term_dictionary
.range()
.ge([0u8])
.lt([5u8])
.backward()
.into_stream();
assert_eq!(value_list(range, true), vec![0u32, 1u32, 2u32, 3u32, 4u32]);
}
}
#[test]
fn test_automaton_search() {
use crate::query::DFAWrapper;
use levenshtein_automata::LevenshteinAutomatonBuilder;
const COUNTRIES: [&'static str; 7] = [
"San Marino",
"Serbia",
"Slovakia",
"Slovenia",
"Spain",
"Sweden",
"Switzerland",
];
let mut directory = RAMDirectory::create();
let path = PathBuf::from("TermDictionary");
{
let write = directory.open_write(&path).unwrap();
let mut term_dictionary_builder = TermDictionaryBuilder::create(write).unwrap();
for term in COUNTRIES.iter() {
term_dictionary_builder
.insert(term.as_bytes(), &make_term_info(0u64))
.unwrap();
}
term_dictionary_builder.finish().unwrap();
}
let source = directory.open_read(&path).unwrap();
let term_dict: TermDictionary = TermDictionary::from_source(&source);
// We can now build an entire dfa.
let lev_automaton_builder = LevenshteinAutomatonBuilder::new(2, true);
let automaton = DFAWrapper(lev_automaton_builder.build_dfa("Spaen"));
let mut range = term_dict.search(automaton).into_stream();
// get the first finding
assert!(range.advance());
assert_eq!("Spain".as_bytes(), range.key());
assert!(!range.advance());
}
}