Evaluate/projects/charset-normalizer/rust/src/md/plugins.rs

use crate::{
    md::structs::{MessDetectorChar, MessDetectorCharFlags},
    utils::{is_suspiciously_successive_range, remove_accent},
};

// Base abstract trait used for mess detection plugins.
// All detectors MUST extend and implement given methods.
pub(super) trait MessDetectorPlugin {
    // Name of plugin
    fn name(&self) -> &str {
        std::any::type_name::<Self>().split("::").last().unwrap()
    }

    // Determine if given character should be fed in
    fn eligible(&self, character: &MessDetectorChar) -> bool;

    // The main routine to be executed upon character.
    // Insert the logic in witch the text would be considered chaotic.
    fn feed(&mut self, character: &MessDetectorChar);

    // Compute the chaos ratio based on what your feed() has seen.
    // Must NOT be lower than 0.; No restriction gt 0.
    fn ratio(&self) -> f32;
}

//
// TooManySymbolOrPunctuationPlugin implementation
//
#[derive(Default)]
pub(super) struct TooManySymbolOrPunctuationPlugin {
    punctuation_count: u64,
    symbol_count: u64,
    character_count: u64,
    last_printable_char: Option<MessDetectorChar>,
}

impl MessDetectorPlugin for TooManySymbolOrPunctuationPlugin {
    fn eligible(&self, character: &MessDetectorChar) -> bool {
        !character.is(MessDetectorCharFlags::UNPRINTABLE)
    }
    fn feed(&mut self, character: &MessDetectorChar) {
        self.character_count += 1;
        if (self.last_printable_char.is_none() || *character != self.last_printable_char.unwrap())
            && !character.is(MessDetectorCharFlags::COMMON_SAFE)
        {
            if character.is(MessDetectorCharFlags::PUNCTUATION) {
                self.punctuation_count += 1;
            } else if !character.is(MessDetectorCharFlags::NUMERIC)
                && character.is(MessDetectorCharFlags::SYMBOL)
                && !character.is(MessDetectorCharFlags::EMOTICON)
            {
                self.symbol_count += 2;
            }
        }
        self.last_printable_char = Some(*character);
    }
    fn ratio(&self) -> f32 {
        if self.character_count == 0 {
            return 0.0;
        }
        let ratio_of_punctuation =
            (self.punctuation_count + self.symbol_count) as f32 / (self.character_count as f32);
        if ratio_of_punctuation >= 0.3 {
            ratio_of_punctuation
        } else {
            0.0
        }
    }
}

//
// TooManyAccentuatedPlugin implementation
//

#[derive(Default)]
pub(super) struct TooManyAccentuatedPlugin {
    character_count: u64,
    accentuated_count: u64,
}

impl MessDetectorPlugin for TooManyAccentuatedPlugin {
    fn eligible(&self, character: &MessDetectorChar) -> bool {
        character.is(MessDetectorCharFlags::ALPHABETIC)
    }
    fn feed(&mut self, character: &MessDetectorChar) {
        self.character_count += 1;
        if character.is(MessDetectorCharFlags::ACCENTUATED) {
            self.accentuated_count += 1;
        }
    }
    fn ratio(&self) -> f32 {
        (self.character_count >= 8)
            .then_some(self.accentuated_count as f32 / self.character_count as f32)
            .filter(|&ratio| ratio >= 0.35)
            .unwrap_or(0.0)
    }
}

//
// UnprintablePlugin implementation
//

#[derive(Default)]
pub(super) struct UnprintablePlugin {
    character_count: u64,
    unprintable_count: u64,
}

impl MessDetectorPlugin for UnprintablePlugin {
    fn eligible(&self, _character: &MessDetectorChar) -> bool {
        true
    }
    fn feed(&mut self, character: &MessDetectorChar) {
        if character.is(MessDetectorCharFlags::UNPRINTABLE) {
            self.unprintable_count += 1;
        }
        self.character_count += 1;
    }
    fn ratio(&self) -> f32 {
        if self.character_count == 0 {
            return 0.0;
        }
        (self.unprintable_count as f32 * 8.0) / self.character_count as f32
    }
}

//
// SuspiciousDuplicateAccentPlugin implementation
//
#[derive(Default)]
pub(super) struct SuspiciousDuplicateAccentPlugin {
    character_count: u64,
    successive_count: u64,
    last_latin_character: Option<MessDetectorChar>,
}

impl MessDetectorPlugin for SuspiciousDuplicateAccentPlugin {
    fn eligible(&self, character: &MessDetectorChar) -> bool {
        character.is(MessDetectorCharFlags::ALPHABETIC)
            && character.is(MessDetectorCharFlags::LATIN)
    }
    fn feed(&mut self, character: &MessDetectorChar) {
        self.character_count += 1;
        if self.last_latin_character.is_some()
            && character.is(MessDetectorCharFlags::ACCENTUATED)
            && self
                .last_latin_character
                .unwrap()
                .is(MessDetectorCharFlags::ACCENTUATED)
        {
            if character.is(MessDetectorCharFlags::UPPERCASE)
                && self
                    .last_latin_character
                    .unwrap()
                    .is(MessDetectorCharFlags::UPPERCASE)
            {
                self.successive_count += 1;
            }

            // Worse if its the same char duplicated with different accent.
            if remove_accent(character.character)
                == remove_accent(self.last_latin_character.unwrap().character)
            {
                self.successive_count += 1;
            }
        }
        self.last_latin_character = Some(*character);
    }
    fn ratio(&self) -> f32 {
        if self.character_count == 0 {
            return 0.0;
        }
        (self.successive_count as f32 * 2.0) / self.character_count as f32
    }
}

//
// SuspiciousRangePlugin implementation
//
#[derive(Default)]
pub(super) struct SuspiciousRangePlugin {
    character_count: u64,
    suspicious_successive_range_count: u64,
    last_printable_char: Option<MessDetectorChar>,
}

impl MessDetectorPlugin for SuspiciousRangePlugin {
    fn eligible(&self, character: &MessDetectorChar) -> bool {
        !character.is(MessDetectorCharFlags::UNPRINTABLE)
    }
    fn feed(&mut self, character: &MessDetectorChar) {
        self.character_count += 1;

        if character.is(MessDetectorCharFlags::WHITESPACE)
            || character.is(MessDetectorCharFlags::PUNCTUATION)
            || character.is(MessDetectorCharFlags::COMMON_SAFE)
        {
            self.last_printable_char = None;
            return;
        }

        if self.last_printable_char.is_none() {
            self.last_printable_char = Some(*character);
            return;
        }

        if is_suspiciously_successive_range(
            self.last_printable_char.unwrap().unicode_range,
            character.unicode_range,
        ) {
            self.suspicious_successive_range_count += 1;
        }

        self.last_printable_char = Some(*character);
    }
    fn ratio(&self) -> f32 {
        (self.character_count > 0)
            .then_some(
                ((self.suspicious_successive_range_count as f32) * 2.0)
                    / self.character_count as f32,
            )
            .filter(|&ratio| ratio >= 0.1)
            .unwrap_or(0.0)
    }
}

//
// SuperWeirdWordPlugin implementation
//

#[derive(Default)]
pub(super) struct SuperWeirdWordPlugin {
    character_count: u64,
    word_count: u64,
    bad_word_count: u64,
    foreign_long_count: u64,
    is_current_word_bad: bool,
    foreign_long_watch: bool,
    bad_character_count: u64,
    buffer_accent_count: u64,
    buffer: Vec<MessDetectorChar>,
}

impl MessDetectorPlugin for SuperWeirdWordPlugin {
    fn eligible(&self, _character: &MessDetectorChar) -> bool {
        true
    }
    fn feed(&mut self, character: &MessDetectorChar) {
        if character.is(MessDetectorCharFlags::ASCII_ALPHABETIC) {
            self.buffer.push(*character);
            if character.is(MessDetectorCharFlags::ACCENTUATED) {
                self.buffer_accent_count += 1;
            }
            self.foreign_long_watch |= (!character.is(MessDetectorCharFlags::LATIN)
                || character.is(MessDetectorCharFlags::ACCENTUATED))
                && !character.is(MessDetectorCharFlags::CJK)
                && !character.is(MessDetectorCharFlags::HANGUL)
                && !character.is(MessDetectorCharFlags::KATAKANA)
                && !character.is(MessDetectorCharFlags::HIRAGANA)
                && !character.is(MessDetectorCharFlags::THAI);
            return;
        }
        if self.buffer.is_empty() {
            return;
        }

        if character.is(MessDetectorCharFlags::WHITESPACE)
            || character.is(MessDetectorCharFlags::PUNCTUATION)
            || character.is(MessDetectorCharFlags::SEPARATOR)
        {
            self.word_count += 1;
            let buffer_length = self.buffer.len();
            self.character_count += buffer_length as u64;

            if buffer_length >= 4 {
                if (self.buffer_accent_count as f32 / buffer_length as f32) > 0.34 {
                    self.is_current_word_bad = true;
                }

                // Word/Buffer ending with an upper case accentuated letter are so rare,
                // that we will consider them all as suspicious. Same weight as foreign_long suspicious.
                let last_char = self.buffer.last().unwrap();
                if last_char.is(MessDetectorCharFlags::ACCENTUATED)
                    && last_char.is(MessDetectorCharFlags::UPPERCASE)
                {
                    self.foreign_long_count += 1;
                    self.is_current_word_bad = true;
                }
            }
            if buffer_length >= 24 && self.foreign_long_watch {
                let uppercase_count = self
                    .buffer
                    .iter()
                    .filter(|&c| c.is(MessDetectorCharFlags::UPPERCASE))
                    .count();
                let mut probable_camel_cased: bool = false;

                if uppercase_count > 0 && (uppercase_count as f32 / buffer_length as f32) <= 0.3 {
                    probable_camel_cased = true;
                }

                if !probable_camel_cased {
                    self.foreign_long_count += 1;
                    self.is_current_word_bad = true;
                }
            }

            if self.is_current_word_bad {
                self.bad_word_count += 1;
                self.bad_character_count += self.buffer.len() as u64;
                self.is_current_word_bad = false;
            }

            self.foreign_long_watch = false;
            self.buffer.clear();
            self.buffer_accent_count = 0;
        } else if !character.is(MessDetectorCharFlags::WEIRD_SAFE)
            && !character.is(MessDetectorCharFlags::ASCII_DIGIT)
            && character.is(MessDetectorCharFlags::SYMBOL)
        {
            self.is_current_word_bad = true;
            self.buffer.push(*character);
        }
    }
    fn ratio(&self) -> f32 {
        if self.word_count <= 10 && self.foreign_long_count == 0 {
            return 0.0;
        }
        self.bad_character_count as f32 / self.character_count as f32
    }
}

//
// CjkInvalidStopPlugin implementation
//
// GB(Chinese) based encoding often render the stop incorrectly when the content does not fit and
// can be easily detected. Searching for the overuse of '丅' and '丄'.
#[derive(Default)]
pub(super) struct CjkInvalidStopPlugin {
    wrong_stop_count: u64,
    cjk_character_count: u64,
}

impl MessDetectorPlugin for CjkInvalidStopPlugin {
    fn eligible(&self, _: &MessDetectorChar) -> bool {
        true
    }
    fn feed(&mut self, character: &MessDetectorChar) {
        if "丅丄".contains(character.character) {
            self.wrong_stop_count += 1;
            return;
        }
        if character.is(MessDetectorCharFlags::CJK) {
            self.cjk_character_count += 1;
        }
    }
    fn ratio(&self) -> f32 {
        if self.cjk_character_count < 16 {
            return 0.0;
        }
        self.wrong_stop_count as f32 / self.cjk_character_count as f32
    }
}

//
// ArchaicUpperLowerPlugin implementation
//

pub(super) struct ArchaicUpperLowerPlugin {
    buf: bool,
    current_ascii_only: bool,
    character_count_since_last_sep: u64,
    successive_upper_lower_count: u64,
    successive_upper_lower_count_final: u64,
    character_count: u64,
    last_alpha_seen: Option<MessDetectorChar>,
}

impl Default for ArchaicUpperLowerPlugin {
    fn default() -> Self {
        ArchaicUpperLowerPlugin {
            buf: false,
            current_ascii_only: true,
            character_count_since_last_sep: 0,
            successive_upper_lower_count: 0,
            successive_upper_lower_count_final: 0,
            character_count: 0,
            last_alpha_seen: None,
        }
    }
}

impl MessDetectorPlugin for ArchaicUpperLowerPlugin {
    fn eligible(&self, _: &MessDetectorChar) -> bool {
        true
    }
    fn feed(&mut self, character: &MessDetectorChar) {
        if !(character.is(MessDetectorCharFlags::ALPHABETIC)
            && character.is(MessDetectorCharFlags::CASE_VARIABLE))
            && self.character_count_since_last_sep > 0
        {
            if self.character_count_since_last_sep <= 64
                && !character.is(MessDetectorCharFlags::ASCII_DIGIT)
                && !self.current_ascii_only
            {
                self.successive_upper_lower_count_final += self.successive_upper_lower_count;
            }

            self.successive_upper_lower_count = 0;
            self.character_count_since_last_sep = 0;
            self.last_alpha_seen = None;
            self.buf = false;
            self.character_count += 1;
            self.current_ascii_only = true;

            return;
        }

        self.current_ascii_only &= character.is(MessDetectorCharFlags::ASCII);

        if let Some(tmp_last_alpha) = self.last_alpha_seen {
            if (character.is(MessDetectorCharFlags::UPPERCASE)
                && tmp_last_alpha.is(MessDetectorCharFlags::LOWERCASE))
                || (character.is(MessDetectorCharFlags::LOWERCASE)
                    && tmp_last_alpha.is(MessDetectorCharFlags::UPPERCASE))
            {
                if self.buf {
                    self.successive_upper_lower_count += 2;
                    self.buf = false;
                } else {
                    self.buf = true;
                }
            } else {
                self.buf = false;
            }
        }

        self.character_count += 1;
        self.character_count_since_last_sep += 1;
        self.last_alpha_seen = Some(*character);
    }
    fn ratio(&self) -> f32 {
        if self.character_count == 0 {
            return 0.0;
        }
        self.successive_upper_lower_count_final as f32 / self.character_count as f32
    }
}