html2md/scraper/
styles.rs

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use super::StructuredPrinter;
use super::TagHandler;
use markup5ever_rcdom::{Handle, NodeData};

#[derive(Default)]
pub struct StyleHandler {
    start_pos: usize,
    style_type: String,
}

/// Applies givem `mark` at both start and end indices, updates printer position to the end of text
fn apply_at_bounds(printer: &mut StructuredPrinter, start: usize, end: usize, mark: &str) {
    printer.data.insert_str(end, mark);
    printer.data.insert_str(start, mark);
}

impl TagHandler for StyleHandler {
    fn handle(&mut self, tag: &Handle, printer: &mut StructuredPrinter) {
        self.start_pos = printer.data.len();
        self.style_type = match tag.data {
            NodeData::Element { ref name, .. } => name.local.to_string(),
            _ => String::new(),
        };
    }

    fn after_handle(&mut self, printer: &mut StructuredPrinter) {
        if let Some(non_space_offset) = printer.data[self.start_pos..]
            .char_indices()
            .find_map(|(i, ch)| if !ch.is_whitespace() { Some(i) } else { None })
        {
            let first_non_space_pos = self.start_pos + non_space_offset;
            let last_non_space_pos = printer
                .data
                .trim_end_matches(|ch: char| ch.is_whitespace())
                .len();

            // finishing markup
            match self.style_type.as_ref() {
                "b" | "strong" => {
                    apply_at_bounds(printer, first_non_space_pos, last_non_space_pos, "**")
                }
                "i" | "em" => {
                    apply_at_bounds(printer, first_non_space_pos, last_non_space_pos, "*")
                }
                "s" | "del" => {
                    apply_at_bounds(printer, first_non_space_pos, last_non_space_pos, "~~")
                }
                "u" | "ins" => {
                    apply_at_bounds(printer, first_non_space_pos, last_non_space_pos, "__")
                }
                _ => (),
            }
        }
    }
}