css_variable_machine.rs — tailwindcss Source File

Source Code

use crate::cursor;
use crate::extractor::machine::{Machine, MachineState};
use classification_macros::ClassifyBytes;

/// Extract CSS variables from an input.
///
/// E.g.:
///
/// ```text
/// var(--my-variable)
///     ^^^^^^^^^^^^^
/// ```
#[derive(Debug, Default)]
pub struct CssVariableMachine;

impl Machine for CssVariableMachine {
    #[inline(always)]
    fn reset(&mut self) {}

    #[inline]
    fn next(&mut self, cursor: &mut cursor::Cursor<'_>) -> MachineState {
        // CSS Variables must start with `--`
        if Class::Dash != cursor.curr.into() || Class::Dash != cursor.next.into() {
            return MachineState::Idle;
        }

        let start_pos = cursor.pos;
        let len = cursor.input.len();

        cursor.advance_twice();

        while cursor.pos < len {
            match cursor.curr.into() {
                // https://drafts.csswg.org/css-syntax-3/#ident-token-diagram
                //
                Class::AllowedCharacter | Class::Dash => {
                    match cursor.next.into() {
                        // Valid character followed by a valid character or an escape character
                        //
                        // E.g.: `--my-variable`
                        //                ^^
                        // E.g.: `--my-\#variable`
                        //            ^^
                        Class::AllowedCharacter | Class::Dash | Class::Escape => cursor.advance(),

                        // Valid character followed by anything else means the variable is done
                        //
                        // E.g.: `'--my-variable'`
                        //                      ^
                        _ => {
                            // There must be at least 1 character after the `--`
                            if cursor.pos - start_pos < 2 {
                                return self.restart();
                            } else {
                                return self.done(start_pos, cursor);
                            }
                        }
                    }
                }

// ... (155 more lines)