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//! A tiny and limited glob matcher implementation for FR Tries (optional)
pub mod acl;
use std::cell::RefCell;
use std::sync::Arc;
use crate::matcher::{Ahead, Event, MatchType, PushdownStateMachine, State, StateSequence};
#[derive(Debug)]
pub struct MachineInstance {
tokens: Vec<Arc<StateSequence>>,
state: State,
glob_idx: usize,
glob_char_idx: usize,
}
impl MachineInstance {
#[inline]
fn feed(&mut self, ev: Event) {
match (&self.state, ev) {
(State::Accepting | State::Expecting, Event::EndOfStream) => {
if self.at_end() {
match &self.state {
State::Accepting => {
self.state = State::Accepted;
}
State::Expecting => {
self.state = State::Accepted;
}
State::Accepted => {
self.state = State::Accepted;
}
State::Rejected => {
self.state = State::Rejected;
}
State::Beyond => {
self.state = State::Beyond;
}
State::Failure(msg) => {
self.state = State::Failure(msg.clone());
}
}
}
else {
match self.look_ahead() {
None => {
self.state = State::Accepted;
}
Some(_ahead) => {
self.state = State::Rejected;
}
}
}
},
(State::Accepting | State::Expecting, Event::CharIn(ch)) => {
match self.look_ahead() {
None => {
self.state = State::Beyond;
}
Some(ahead) => {
match ahead {
Ahead::Exactly(current_char) => {
if current_char == ch {
self.advance();
if self.at_end() {
//self.state = State::Accepted;
}
else {
//self.state = State::Expecting;
}
}
else if ch < current_char {
self.state = State::Beyond;
}
else {
self.state = State::Rejected;
}
}
Ahead::AnyOr(current_char) => {
if current_char == ch {
self.advance();
if self.at_end() {
//self.state = State::Accepted;
}
self.state = State::Accepting;
}
}
Ahead::Any => {
self.state = State::Accepting;
}
}
}
}
}
(s, e) => {
self.state = State::Failure(format!("Wrong state, event combination: {:#?} {:#?}", s, e)
.to_string())
}
}
}
#[inline]
fn look_ahead(&self) -> Option<Ahead> {
match self.tokens.get(self.glob_idx) {
None => {
return None; // Exceeding limits
}
Some(current_glob) => {
match current_glob.sequence.get(self.glob_char_idx) {
None => {
match current_glob.match_type {
MatchType::Literal => {
return None;
}
MatchType::AnyOr => {
return Some(Ahead::Any)
}
}
}
Some(current_char) => {
match current_glob.match_type {
MatchType::Literal => {
return Some(Ahead::Exactly(*current_char))
}
MatchType::AnyOr => {
return Some(Ahead::AnyOr(*current_char))
}
}
}
}
}
}
}
#[inline]
fn advance(&mut self) {
match self.tokens.get(self.glob_idx) {
None => {
panic!("Cannot advance");
}
Some(current_glob) => {
if self.glob_char_idx < current_glob.sequence.len() - 1 {
self.glob_char_idx += 1;
}
else if self.glob_idx < self.tokens.len() - 1 {
self.glob_char_idx = 0;
self.glob_idx += 1;
}
else { // Position at END
self.glob_char_idx = 0;
self.glob_idx = self.tokens.len();
}
}
}
}
#[inline]
fn at_end(&self) -> bool {
match self.tokens.get(self.glob_idx) {
None => {
true
}
Some(current_glob) => {
if self.glob_idx + 1 >= self.tokens.len() {
if self.glob_char_idx + 1 > current_glob.sequence.len() {
return true;
}
else {
return false;
}
}
else {
return false;
}
}
}
}
#[inline]
fn is_expecting(&self) -> bool {
match self.tokens.get(self.glob_idx) {
None => {
false
}
Some(_) => {
if self.glob_idx == self.tokens.len() {
return false;
}
else {
return true;
}
}
}
}
}
/////////////////////////////
#[derive(Debug, Clone)]
pub struct GlobMatcher {
stack: Vec<Arc<RefCell<MachineInstance>>>,
}
impl PushdownStateMachine for GlobMatcher {
fn new() -> Self {
Self {
stack: Vec::new(),
}
}
#[inline]
fn step_in(&mut self, sequence: &Vec<Arc<StateSequence>>) {
let new_instance = match self.stack.last() {
None => {
let initial_state = match sequence.first() {
None => {
State::Failure(String::from("No regexp provided"))
}
Some(first_seq) => {
match first_seq.match_type {
MatchType::Literal => {
State::Expecting
},
MatchType::AnyOr => {
State::Accepting
},
}
}
};
Arc::new(RefCell::new(MachineInstance {
tokens: sequence.clone(),
state: initial_state,
glob_idx: 0,
glob_char_idx: 0,
}))
}
Some(top) => {
let machine = top.borrow();
let mut tokens = machine.tokens.clone();
for aditional_token in sequence {
tokens.push(aditional_token.clone());
}
Arc::new(RefCell::new(MachineInstance {
tokens,
state: machine.state.clone(),
glob_idx: machine.glob_idx,
glob_char_idx: machine.glob_char_idx,
}))
}
};
self.stack.push(new_instance);
}
#[inline]
fn step_out(&mut self) {
let _k = self.stack.pop();
}
#[inline]
fn accepts_more(&self) -> bool {
match self.stack.last() {
Some(machine) => machine.borrow().is_expecting(),
None => false
}
}
#[inline]
fn feed(&mut self, ev: Event) {
match self.stack.last_mut() {
Some(machine) => machine.borrow_mut().feed(ev),
None => {}
}
}
#[inline]
fn state(&self) -> State {
match self.stack.last() {
Some(machine) => machine.borrow().state.clone(),
None => State::Failure(String::from("Machine not initiallized"))
}
}
#[inline]
fn is_sink(&self) -> bool {
match self.stack.last() {
Some(machine) => match machine.borrow().state {
State::Accepting => false,
State::Expecting => false,
State::Accepted => true,
State::Rejected => true,
State::Beyond => true,
State::Failure(_) => true,
},
None => true,
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn matcher_test() {
let mut expected_token_sequence: Vec<Arc<StateSequence>> = Vec::new();
expected_token_sequence.push(Arc::new(StateSequence {
match_type: MatchType::Literal,
sequence: String::from("123").chars().collect()
}));
let mut matcher = GlobMatcher::new();
matcher.step_in(&expected_token_sequence);
let str: Vec<char> = String::from("12345").chars().collect();
let mut input = str.iter();
matcher.feed(Event::CharIn(*input.next().unwrap()));
matcher.feed(Event::CharIn(*input.next().unwrap()));
matcher.feed(Event::CharIn(*input.next().unwrap()));
matcher.feed(Event::EndOfStream);
let _st = matcher.state();
let _st = matcher.accepts_more();
matcher.feed(Event::CharIn(*input.next().unwrap()));
let _st = matcher.state();
let _st = matcher.accepts_more();
println!("{:?}", matcher.stack.last().unwrap());
let mi = matcher.stack.last().unwrap();
let _v = mi.as_ref().borrow().look_ahead();
let _v = mi.as_ref().borrow().is_expecting();
matcher.step_out();
let _st = matcher.state();
let _st = matcher.accepts_more();
matcher.feed(Event::CharIn(*input.next().unwrap()));
println!("{:?}", matcher.clone());
expected_token_sequence.push(Arc::new(StateSequence {
match_type: MatchType::AnyOr,
sequence: Vec::new()
}));
let str: Vec<char> = String::from("12345").chars().collect();
let mut input = str.iter();
matcher.step_out();
matcher.step_in(&expected_token_sequence);
matcher.feed(Event::CharIn(*input.next().unwrap()));
let _st = matcher.state();
let _st = matcher.accepts_more();
let mi = matcher.stack.last().unwrap();
let _v = mi.as_ref().borrow().look_ahead();
let _v = mi.as_ref().borrow().is_expecting();
}
}