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use crate::tokenizer::TokenStreamChain;
use std::borrow::{Borrow, BorrowMut};
use std::ops::{Deref, DerefMut};
#[derive(Debug, Clone, Serialize, Deserialize, Eq, PartialEq)]
pub struct Token {
pub offset_from: usize,
pub offset_to: usize,
pub position: usize,
pub text: String,
pub position_length: usize,
}
impl Default for Token {
fn default() -> Token {
Token {
offset_from: 0,
offset_to: 0,
position: usize::max_value(),
text: String::with_capacity(200),
position_length: 1,
}
}
}
pub struct TextAnalyzer {
tokenizer: Box<dyn Tokenizer>,
token_filters: Vec<BoxTokenFilter>,
}
impl<T: Tokenizer> From<T> for TextAnalyzer {
fn from(tokenizer: T) -> Self {
TextAnalyzer::new(tokenizer, Vec::new())
}
}
impl TextAnalyzer {
pub fn new<T: Tokenizer>(tokenizer: T, token_filters: Vec<BoxTokenFilter>) -> TextAnalyzer {
TextAnalyzer {
tokenizer: Box::new(tokenizer),
token_filters,
}
}
pub fn filter<F: Into<BoxTokenFilter>>(mut self, token_filter: F) -> Self {
self.token_filters.push(token_filter.into());
self
}
pub fn token_stream_texts<'a>(&self, texts: &'a [&'a str]) -> BoxTokenStream<'a> {
assert!(!texts.is_empty());
if texts.len() == 1 {
self.token_stream(texts[0])
} else {
let mut offsets = vec![];
let mut total_offset = 0;
for &text in texts {
offsets.push(total_offset);
total_offset += text.len();
}
let token_streams: Vec<BoxTokenStream<'a>> = texts
.iter()
.cloned()
.map(|text| self.token_stream(text))
.collect();
From::from(TokenStreamChain::new(offsets, token_streams))
}
}
pub fn token_stream<'a>(&self, text: &'a str) -> BoxTokenStream<'a> {
let mut token_stream = self.tokenizer.token_stream(text);
for token_filter in &self.token_filters {
token_stream = token_filter.transform(token_stream);
}
token_stream
}
}
impl Clone for TextAnalyzer {
fn clone(&self) -> Self {
TextAnalyzer {
tokenizer: self.tokenizer.box_clone(),
token_filters: self
.token_filters
.iter()
.map(|token_filter| token_filter.box_clone())
.collect(),
}
}
}
pub trait Tokenizer: 'static + Send + Sync + TokenizerClone {
fn token_stream<'a>(&self, text: &'a str) -> BoxTokenStream<'a>;
}
pub trait TokenizerClone {
fn box_clone(&self) -> Box<dyn Tokenizer>;
}
impl<T: Tokenizer + Clone> TokenizerClone for T {
fn box_clone(&self) -> Box<dyn Tokenizer> {
Box::new(self.clone())
}
}
impl<'a> TokenStream for Box<dyn TokenStream + 'a> {
fn advance(&mut self) -> bool {
let token_stream: &mut dyn TokenStream = self.borrow_mut();
token_stream.advance()
}
fn token<'b>(&'b self) -> &'b Token {
let token_stream: &'b (dyn TokenStream + 'a) = self.borrow();
token_stream.token()
}
fn token_mut<'b>(&'b mut self) -> &'b mut Token {
let token_stream: &'b mut (dyn TokenStream + 'a) = self.borrow_mut();
token_stream.token_mut()
}
}
pub struct BoxTokenStream<'a>(Box<dyn TokenStream + 'a>);
impl<'a, T> From<T> for BoxTokenStream<'a>
where
T: TokenStream + 'a,
{
fn from(token_stream: T) -> BoxTokenStream<'a> {
BoxTokenStream(Box::new(token_stream))
}
}
impl<'a> Deref for BoxTokenStream<'a> {
type Target = dyn TokenStream + 'a;
fn deref(&self) -> &Self::Target {
&*self.0
}
}
impl<'a> DerefMut for BoxTokenStream<'a> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut *self.0
}
}
pub struct BoxTokenFilter(Box<dyn TokenFilter>);
impl Deref for BoxTokenFilter {
type Target = dyn TokenFilter;
fn deref(&self) -> &dyn TokenFilter {
&*self.0
}
}
impl<T: TokenFilter> From<T> for BoxTokenFilter {
fn from(tokenizer: T) -> BoxTokenFilter {
BoxTokenFilter(Box::new(tokenizer))
}
}
pub trait TokenStream {
fn advance(&mut self) -> bool;
fn token(&self) -> &Token;
fn token_mut(&mut self) -> &mut Token;
fn next(&mut self) -> Option<&Token> {
if self.advance() {
Some(self.token())
} else {
None
}
}
fn process(&mut self, sink: &mut dyn FnMut(&Token)) -> u32 {
let mut num_tokens_pushed = 0u32;
while self.advance() {
sink(self.token());
num_tokens_pushed += 1u32;
}
num_tokens_pushed
}
}
pub trait TokenFilterClone {
fn box_clone(&self) -> BoxTokenFilter;
}
pub trait TokenFilter: 'static + Send + Sync + TokenFilterClone {
fn transform<'a>(&self, token_stream: BoxTokenStream<'a>) -> BoxTokenStream<'a>;
}
impl<T: TokenFilter + Clone> TokenFilterClone for T {
fn box_clone(&self) -> BoxTokenFilter {
BoxTokenFilter::from(self.clone())
}
}
#[cfg(test)]
mod test {
use super::Token;
#[test]
fn clone() {
let t1 = Token {
position: 1,
offset_from: 2,
offset_to: 3,
text: "abc".to_string(),
position_length: 1,
};
let t2 = t1.clone();
assert_eq!(t1.position, t2.position);
assert_eq!(t1.offset_from, t2.offset_from);
assert_eq!(t1.offset_to, t2.offset_to);
assert_eq!(t1.text, t2.text);
}
}