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feat: Introduce the QueryEnhancer type

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This commit is contained in:
Clément Renault 2019-07-07 12:41:20 +02:00
parent e0cadaa68d
commit 5e691c2140
3 changed files with 397 additions and 1 deletions
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1
meilidb-core/src/lib.rs
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@ -4,6 +4,7 @@
mod automaton;
mod distinct_map;
mod query_builder;
mod query_enhancer;
mod reordered_attrs;
mod store;
pub mod criterion;

2
meilidb-core/src/query_builder.rs
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@ -6,12 +6,12 @@ use std::{cmp, mem};
use fst::{Streamer, IntoStreamer};
use hashbrown::HashMap;
use levenshtein_automata::DFA;
use log::info;
use meilidb_tokenizer::{is_cjk, split_query_string};
use rayon::slice::ParallelSliceMut;
use sdset::SetBuf;
use slice_group_by::GroupByMut;
use levenshtein_automata::DFA;
use crate::automaton::{build_dfa, build_prefix_dfa};
use crate::distinct_map::{DistinctMap, BufferedDistinctMap};

395
meilidb-core/src/query_enhancer.rs Normal file
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@ -0,0 +1,395 @@
use std::ops::Range;
use std::cmp::Ordering::{Less, Greater, Equal};
/// Return `true` if the specified range can accept the given replacements words.
/// Returns `false` if the replacements words are already present in the original query
/// or if there is fewer replacement words than the range to replace.
//
//
// ## Ignored because already present in original
//
// new york city subway
// -------- ^^^^
// / \
// [new york city]
//
//
// ## Ignored because smaller than the original
//
// new york city subway
// -------------
// \ /
// [new york]
//
//
// ## Accepted because bigger than the original
//
// NYC subway
// ---
// / \
// / \
// / \
// / \
// / \
// [new york city]
//
fn rewrite_range_with<S, T>(query: &[S], range: Range<usize>, words: &[T]) -> bool
where S: AsRef<str>,
T: AsRef<str>,
{
if words.len() <= range.len() {
// there is fewer or equal replacement words
// than there is already in the replaced range
return false
}
// retrieve the part to rewrite but with the length
// of the replacement part
let original = query.iter().skip(range.start).take(words.len());
// check if the original query doesn't already contain
// the replacement words
!original.map(AsRef::as_ref).eq(words.iter().map(AsRef::as_ref))
}
struct FakeIntervalTree {
intervals: Vec<(Range<usize>, (usize, usize))>, // origin, real_length
}
impl FakeIntervalTree {
fn new(mut intervals: Vec<(Range<usize>, (usize, usize))>) -> FakeIntervalTree {
intervals.sort_unstable_by_key(|(r, _)| (r.start, r.end));
FakeIntervalTree { intervals }
}
fn query(&self, point: usize) -> Option<(Range<usize>, (usize, usize))> {
let element = self.intervals.binary_search_by(|(r, _)| {
if point >= r.start {
if point < r.end { Equal } else { Less }
} else { Greater }
});
let n = match element { Ok(n) => n, Err(n) => n };
match self.intervals.get(n) {
Some((range, value)) if range.contains(&point) => Some((range.clone(), *value)),
_otherwise => None,
}
}
}
pub struct QueryEnhancerBuilder<'a, S> {
query: &'a [S],
origins: Vec<usize>,
real_to_origin: Vec<(Range<usize>, (usize, usize))>,
}
impl<S: AsRef<str>> QueryEnhancerBuilder<'_, S> {
pub fn new(query: &[S]) -> QueryEnhancerBuilder<S> {
// we initialize origins query indices based on their positions
let origins: Vec<_> = (0..query.len() + 1).collect();
let real_to_origin = origins.iter().map(|&o| (o..o+1, (o, 1))).collect();
QueryEnhancerBuilder { query, origins, real_to_origin }
}
/// Update the final real to origin query indices mapping.
///
/// `range` is the original words range that this `replacement` words replace
/// and `real` is the first real query index of these replacement words.
pub fn declare<T>(&mut self, range: Range<usize>, real: usize, replacement: &[T])
where T: AsRef<str>,
{
// check if the range of original words
// can be rewritten with the replacement words
if rewrite_range_with(self.query, range.clone(), replacement) {
// this range can be replaced so we need to
// modify the origins accordingly
let offset = replacement.len() - range.len();
let previous_padding = self.origins[range.end - 1];
let current_offset = (self.origins[range.end] - 1) - previous_padding;
let diff = offset.saturating_sub(current_offset);
self.origins[range.end] += diff;
for r in &mut self.origins[range.end + 1..] {
*r += diff;
}
}
// we need to store the real number and origins relations
// this way it will be possible to know by how many
// we need to pad real query indices
let real_range = real..real + replacement.len().max(range.len());
let real_length = replacement.len();
self.real_to_origin.push((real_range, (range.start, real_length)));
}
pub fn build(self) -> QueryEnhancer {
QueryEnhancer {
origins: self.origins,
real_to_origin: FakeIntervalTree::new(self.real_to_origin),
}
}
}
pub struct QueryEnhancer {
origins: Vec<usize>,
real_to_origin: FakeIntervalTree,
}
impl QueryEnhancer {
/// Returns the query indices to use to replace this real query index.
pub fn replacement(&self, real: u32) -> Range<u32> {
let real = real as usize;
// query the fake interval tree with the real query index
let (range, (origin, real_length)) =
self.real_to_origin
.query(real)
.expect("real has never been declared");
// if `real` is the end bound of the range
if (range.start + real_length - 1) == real {
let mut count = range.len();
let mut new_origin = origin;
for (i, slice) in self.origins[new_origin..].windows(2).enumerate() {
let len = slice[1] - slice[0];
count = count.saturating_sub(len);
if count == 0 { new_origin = origin + i; break }
}
let n = real - range.start;
let start = self.origins[origin];
let end = self.origins[new_origin + 1];
let remaining = (end - start) - n;
Range { start: (start + n) as u32, end: (start + n + remaining) as u32 }
} else {
// just return the origin along with
// the real position of the word
let n = real as usize - range.start;
let origin = self.origins[origin];
Range { start: (origin + n) as u32, end: (origin + n + 1) as u32 }
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn original_unmodified() {
let query = ["new", "york", "city", "subway"];
// 0 1 2 3
let mut builder = QueryEnhancerBuilder::new(&query);
// new york = new york city
builder.declare(0..2, 4, &["new", "york", "city"]);
// ^ 4 5 6
let enhancer = builder.build();
assert_eq!(enhancer.replacement(0), 0..1); // new
assert_eq!(enhancer.replacement(1), 1..2); // york
assert_eq!(enhancer.replacement(2), 2..3); // city
assert_eq!(enhancer.replacement(3), 3..4); // subway
assert_eq!(enhancer.replacement(4), 0..1); // new
assert_eq!(enhancer.replacement(5), 1..2); // york
assert_eq!(enhancer.replacement(6), 2..3); // city
}
#[test]
fn simple_growing() {
let query = ["new", "york", "subway"];
// 0 1 2
let mut builder = QueryEnhancerBuilder::new(&query);
// new york = new york city
builder.declare(0..2, 3, &["new", "york", "city"]);
// ^ 3 4 5
let enhancer = builder.build();
assert_eq!(enhancer.replacement(0), 0..1); // new
assert_eq!(enhancer.replacement(1), 1..3); // york
assert_eq!(enhancer.replacement(2), 3..4); // subway
assert_eq!(enhancer.replacement(3), 0..1); // new
assert_eq!(enhancer.replacement(4), 1..2); // york
assert_eq!(enhancer.replacement(5), 2..3); // city
}
#[test]
fn same_place_growings() {
let query = ["NY", "subway"];
// 0 1
let mut builder = QueryEnhancerBuilder::new(&query);
// NY = new york
builder.declare(0..1, 2, &["new", "york"]);
// ^ 2 3
// NY = new york city
builder.declare(0..1, 4, &["new", "york", "city"]);
// ^ 4 5 6
// NY = NYC
builder.declare(0..1, 7, &["NYC"]);
// ^ 7
// NY = new york city
builder.declare(0..1, 8, &["new", "york", "city"]);
// ^ 8 9 10
// subway = underground train
builder.declare(1..2, 11, &["underground", "train"]);
// ^ 11 12
let enhancer = builder.build();
assert_eq!(enhancer.replacement(0), 0..3); // NY
assert_eq!(enhancer.replacement(1), 3..5); // subway
assert_eq!(enhancer.replacement(2), 0..1); // new
assert_eq!(enhancer.replacement(3), 1..3); // york
assert_eq!(enhancer.replacement(4), 0..1); // new
assert_eq!(enhancer.replacement(5), 1..2); // york
assert_eq!(enhancer.replacement(6), 2..3); // city
assert_eq!(enhancer.replacement(7), 0..3); // NYC
assert_eq!(enhancer.replacement(8), 0..1); // new
assert_eq!(enhancer.replacement(9), 1..2); // york
assert_eq!(enhancer.replacement(10), 2..3); // city
assert_eq!(enhancer.replacement(11), 3..4); // underground
assert_eq!(enhancer.replacement(12), 4..5); // train
}
#[test]
fn bigger_growing() {
let query = ["NYC", "subway"];
// 0 1
let mut builder = QueryEnhancerBuilder::new(&query);
// NYC = new york city
builder.declare(0..1, 2, &["new", "york", "city"]);
// ^ 2 3 4
let enhancer = builder.build();
assert_eq!(enhancer.replacement(0), 0..3); // NYC
assert_eq!(enhancer.replacement(1), 3..4); // subway
assert_eq!(enhancer.replacement(2), 0..1); // new
assert_eq!(enhancer.replacement(3), 1..2); // york
assert_eq!(enhancer.replacement(4), 2..3); // city
}
#[test]
fn middle_query_growing() {
let query = ["great", "awesome", "NYC", "subway"];
// 0 1 2 3
let mut builder = QueryEnhancerBuilder::new(&query);
// NYC = new york city
builder.declare(2..3, 4, &["new", "york", "city"]);
// ^ 4 5 6
let enhancer = builder.build();
assert_eq!(enhancer.replacement(0), 0..1); // great
assert_eq!(enhancer.replacement(1), 1..2); // awesome
assert_eq!(enhancer.replacement(2), 2..5); // NYC
assert_eq!(enhancer.replacement(3), 5..6); // subway
assert_eq!(enhancer.replacement(4), 2..3); // new
assert_eq!(enhancer.replacement(5), 3..4); // york
assert_eq!(enhancer.replacement(6), 4..5); // city
}
#[test]
fn end_query_growing() {
let query = ["NYC", "subway"];
// 0 1
let mut builder = QueryEnhancerBuilder::new(&query);
// NYC = new york city
builder.declare(1..2, 2, &["underground", "train"]);
// ^ 2 3
let enhancer = builder.build();
assert_eq!(enhancer.replacement(0), 0..1); // NYC
assert_eq!(enhancer.replacement(1), 1..3); // subway
assert_eq!(enhancer.replacement(2), 1..2); // underground
assert_eq!(enhancer.replacement(3), 2..3); // train
}
#[test]
fn multiple_growings() {
let query = ["great", "awesome", "NYC", "subway"];
// 0 1 2 3
let mut builder = QueryEnhancerBuilder::new(&query);
// NYC = new york city
builder.declare(2..3, 4, &["new", "york", "city"]);
// ^ 4 5 6
// subway = underground train
builder.declare(3..4, 7, &["underground", "train"]);
// ^ 7 8
let enhancer = builder.build();
assert_eq!(enhancer.replacement(0), 0..1); // great
assert_eq!(enhancer.replacement(1), 1..2); // awesome
assert_eq!(enhancer.replacement(2), 2..5); // NYC
assert_eq!(enhancer.replacement(3), 5..7); // subway
assert_eq!(enhancer.replacement(4), 2..3); // new
assert_eq!(enhancer.replacement(5), 3..4); // york
assert_eq!(enhancer.replacement(6), 4..5); // city
assert_eq!(enhancer.replacement(7), 5..6); // underground
assert_eq!(enhancer.replacement(8), 6..7); // train
}
#[test]
fn multiple_probable_growings() {
let query = ["great", "awesome", "NYC", "subway"];
// 0 1 2 3
let mut builder = QueryEnhancerBuilder::new(&query);
// NYC = new york city
builder.declare(2..3, 4, &["new", "york", "city"]);
// ^ 4 5 6
// subway = underground train
builder.declare(3..4, 7, &["underground", "train"]);
// ^ 7 8
// great awesome = good
builder.declare(0..2, 9, &["good"]);
// ^ 9
// awesome NYC = NY
builder.declare(1..3, 10, &["NY"]);
// ^^ 10
// NYC subway = metro
builder.declare(2..4, 11, &["metro"]);
// ^^ 11
let enhancer = builder.build();
assert_eq!(enhancer.replacement(0), 0..1); // great
assert_eq!(enhancer.replacement(1), 1..2); // awesome
assert_eq!(enhancer.replacement(2), 2..5); // NYC
assert_eq!(enhancer.replacement(3), 5..7); // subway
assert_eq!(enhancer.replacement(4), 2..3); // new
assert_eq!(enhancer.replacement(5), 3..4); // york
assert_eq!(enhancer.replacement(6), 4..5); // city
assert_eq!(enhancer.replacement(7), 5..6); // underground
assert_eq!(enhancer.replacement(8), 6..7); // train
assert_eq!(enhancer.replacement(9), 0..2); // good
assert_eq!(enhancer.replacement(10), 1..5); // NY
assert_eq!(enhancer.replacement(11), 2..5); // metro
}
}