Method choose_quotes

crates/ruff_python_formatter/src/string/normalize.rs:193–234

Computes the strings preferred quotes.

(&self, string: StringLikePart)

    /// Computes the strings preferred quotes.
    pub(crate) fn choose_quotes(&self, string: StringLikePart) -> QuoteSelection {
        let raw_content = &self.context.source()[string.content_range()];
        let first_quote_or_normalized_char_offset = raw_content
            .bytes()
            .position(|b| matches!(b, b'\\' | b'"' | b'\'' | b'\r'));
        let string_flags = string.flags();
        let preferred_style = self.preferred_quote_style(string);

        let new_kind = match (
            Quote::try_from(preferred_style),
            first_quote_or_normalized_char_offset,
        ) {
            // The string contains no quotes so it's safe to use the preferred quote style
            (Ok(preferred_quote), None) => string_flags.with_quote_style(preferred_quote),

            // The preferred quote style is single or double quotes, and the string contains a quote or
            // another character that may require escaping
            (Ok(preferred_quote), Some(first_quote_or_normalized_char_offset)) => {
                let metadata = if string.is_interpolated_string() {
                    QuoteMetadata::from_part(string, self.context, preferred_quote)
                } else {
                    QuoteMetadata::from_str(
                        &raw_content[first_quote_or_normalized_char_offset..],
                        string.flags(),
                        preferred_quote,
                    )
                };

                let quote = metadata.choose(preferred_quote);

                string_flags.with_quote_style(quote)
            }

            // The preferred quote style is to preserve the quotes, so let's do that.
            (Err(()), _) => string_flags,
        };

        QuoteSelection {
            flags: new_kind,
            first_quote_or_normalized_char_offset,
        }
    }

    /// Computes the strings preferred quotes and normalizes its content.
    pub(crate) fn normalize(&self, string: StringLikePart) -> NormalizedString<'src> {