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| -rw-r--r-- | src/util.rs | 341 |
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diff --git a/src/util.rs b/src/util.rs deleted file mode 100644 index accc48e..0000000 --- a/src/util.rs +++ /dev/null @@ -1,341 +0,0 @@ -//! Some utilities helpful when parsing and compiling markdown. - -use crate::constant::{CHARACTER_REFERENCE_NAMES, CHARACTER_REFERENCE_VALUES}; -use crate::tokenizer::{Code, Event, EventType}; - -/// Encode dangerous html characters. -/// -/// This ensures that certain characters which have special meaning in HTML are -/// dealt with. -/// Technically, we can skip `>` and `"` in many cases, but CM includes them. -/// -/// This behavior is not explained in prose in `CommonMark` but can be inferred -/// from the input/output test cases. -/// -/// ## Examples -/// -/// ```rust ignore -/// use micromark::util::encode; -/// -/// assert_eq!(encode("I <3 🦀"), "I <3 🦀"); -/// ``` -/// -/// ## References -/// -/// * [`micromark-util-encode` in `micromark`](https://github.com/micromark/micromark/tree/main/packages/micromark-util-encode) -pub fn encode(value: &str) -> String { - value - .replace('&', "&") - .replace('"', """) - .replace('<', "<") - .replace('>', ">") -} - -/// Make a value safe for injection as a URL. -/// -/// This encodes unsafe characters with percent-encoding and skips already -/// encoded sequences (see `normalize_uri` below). -/// Further unsafe characters are encoded as character references (see -/// `encode`). -/// -/// Then, a vec of (lowercase) allowed protocols can be given, in which case -/// the URL is sanitized. -/// -/// For example, `Some(vec!["http", "https", "irc", "ircs", "mailto", "xmpp"])` -/// can be used for `a[href]`, or `Some(vec!["http", "https"])` for `img[src]`. -/// If the URL includes an unknown protocol (one not matched by `protocol`, such -/// as a dangerous example, `javascript:`), the value is ignored. -pub fn sanitize_uri(value: &str, protocols: &Option<Vec<&str>>) -> String { - let value = encode(&normalize_uri(value)); - - if let Some(protocols) = protocols { - let chars: Vec<char> = value.chars().collect(); - let mut index = 0; - let mut colon: Option<usize> = None; - - while index < chars.len() { - let char = chars[index]; - - match char { - ':' => { - colon = Some(index); - break; - } - '?' | '#' | '/' => break, - _ => {} - } - - index += 1; - } - - // If there is no protocol, or the first colon is after `?`, `#`, or `/`, it’s relative. - // It is a protocol, it should be allowed. - if let Some(colon) = colon { - let protocol = chars[0..colon].iter().collect::<String>().to_lowercase(); - if !protocols.contains(&protocol.as_str()) { - return "".to_string(); - } - } - } - - value -} - -/// Normalize a URL (such as used in definitions). -/// -/// Encode unsafe characters with percent-encoding, skipping already encoded -/// sequences. -fn normalize_uri(value: &str) -> String { - let chars: Vec<char> = value.chars().collect(); - let mut result: Vec<String> = vec![]; - let mut index = 0; - let mut start = 0; - let mut buff = [0; 4]; - - while index < chars.len() { - let char = chars[index]; - - // A correct percent encoded value. - if char == '%' - && index + 2 < chars.len() - && chars[index + 1].is_ascii_alphanumeric() - && chars[index + 2].is_ascii_alphanumeric() - { - index += 3; - continue; - } - - // Note: Rust already takes care of lone astral surrogates. - // Non-ascii or not allowed ascii. - if char >= '\u{0080}' - || !matches!(char, '!' | '#' | '$' | '&'..=';' | '=' | '?'..='Z' | '_' | 'a'..='z' | '~') - { - result.push(chars[start..index].iter().collect::<String>()); - - char.encode_utf8(&mut buff); - result.push( - buff[0..char.len_utf8()] - .iter() - .map(|&byte| format!("%{:X}", byte)) - .collect::<String>(), - ); - - start = index + 1; - } - - index += 1; - } - - result.push(chars[start..].iter().collect::<String>()); - - result.join("") -} - -/// Decode numeric character references. -/// -/// Turn the number (in string form as either hexadecimal or decimal) coming -/// from a numeric character reference into a character. -/// Whether the base of the string form is `10` (decimal) or `16` (hexadecimal) -/// must be passed as the `radix` parameter. -/// -/// This returns the `char` associated with that number or a replacement -/// character for C0 control characters (except for ASCII whitespace), C1 -/// control characters, lone surrogates, noncharacters, and out of range -/// characters. -/// -/// ## Examples -/// -/// ```rust ignore -/// use micromark::util::decode_numeric_character_reference; -/// -/// assert_eq!(decode_numeric_character_reference("123", 10), '{'); -/// assert_eq!(decode_numeric_character_reference("9", 16), '\t'); -/// assert_eq!(decode_numeric_character_reference("0", 10), '�'); // Not allowed. -/// ``` -/// -/// ## Panics -/// -/// This function panics if a invalid string or an out of bounds valid string -/// is given. -/// It is expected that figuring out whether a number is allowed is handled in -/// the parser. -/// When `micromark` is used, this function never panics. -/// -/// ## References -/// -/// * [`micromark-util-decode-numeric-character-reference` in `micromark`](https://github.com/micromark/micromark/tree/main/packages/micromark-util-decode-numeric-character-reference) -/// * [*§ 2.5 Entity and numeric character references* in `CommonMark`](https://spec.commonmark.org/0.30/#entity-and-numeric-character-references) -pub fn decode_numeric_character_reference(value: &str, radix: u32) -> char { - let code = u32::from_str_radix(value, radix).expect("expected `value` to be an int"); - - if - // C0 except for HT, LF, FF, CR, space - code < 0x09 || - code == 0x0B || - (code > 0x0D && code < 0x20) || - // Control character (DEL) of the basic block and C1 controls. - (code > 0x7E && code < 0xA0) || - // Lone high surrogates and low surrogates. - (code > 0xd7ff && code < 0xe000) || - // Noncharacters. - (code > 0xfdcf && code < 0xfdf0) || - ((code & 0xffff) == 0xffff) || - ((code & 0xffff) == 0xfffe) || - // Out of range - code > 0x0010_ffff - { - '�' - } else { - char::from_u32(code).expect("expected valid `code`") - } -} - -/// Decode named character references. -/// -/// Turn the name coming from a named character reference (without the `&` or -/// `;`) into a string. -/// This looks the given string up in [`CHARACTER_REFERENCE_NAMES`][] and then -/// takes the corresponding value from [`CHARACTER_REFERENCE_VALUES`][]. -/// -/// The result is `String` instead of `char` because named character references -/// can expand into multiple characters. -/// -/// ## Examples -/// -/// ```rust ignore -/// use micromark::util::decode_named_character_reference; -/// -/// assert_eq!(decode_named_character_reference("amp"), "&"); -/// assert_eq!(decode_named_character_reference("AElig"), "Æ"); -/// assert_eq!(decode_named_character_reference("aelig"), "æ"); -/// ``` -/// -/// ## Panics -/// -/// This function panics if a name not in [`CHARACTER_REFERENCE_NAMES`][] is -/// given. -/// It is expected that figuring out whether a name is allowed is handled in -/// the parser. -/// When `micromark` is used, this function never panics. -/// -/// ## References -/// -/// * [`wooorm/decode-named-character-reference`](https://github.com/wooorm/decode-named-character-reference) -/// * [*§ 2.5 Entity and numeric character references* in `CommonMark`](https://spec.commonmark.org/0.30/#entity-and-numeric-character-references) -pub fn decode_named_character_reference(value: &str) -> String { - let position = CHARACTER_REFERENCE_NAMES.iter().position(|&x| x == value); - if let Some(index) = position { - CHARACTER_REFERENCE_VALUES[index].to_string() - } else { - unreachable!("expected valid `name`") - } -} - -/// A struct representing the span of an opening and closing event of a token. -#[derive(Debug)] -pub struct Span { - // To do: probably needed in the future. - // start: Point, - /// Absolute offset (and `index` in `codes`) of where this span starts. - pub start_index: usize, - // To do: probably needed in the future. - // end: Point, - /// Absolute offset (and `index` in `codes`) of where this span ends. - pub end_index: usize, - // To do: probably needed in the future. - // token_type: TokenType, -} - -/// Get a span from an event. -/// -/// Get the span of an `exit` event, by looking backwards through the events to -/// find the corresponding `enter` event. -/// This assumes that tokens with the same are not nested. -/// -/// ## Panics -/// -/// This function panics if an enter event is given. -/// When `micromark` is used, this function never panics. -pub fn get_span(events: &[Event], index: usize) -> Span { - let exit = &events[index]; - // let end = exit.point.clone(); - let end_index = exit.index; - let token_type = exit.token_type.clone(); - // To do: support `enter` events if needed and walk forwards? - assert_eq!( - exit.event_type, - EventType::Exit, - "expected `get_span` to be called on `exit` event" - ); - let mut enter_index = index - 1; - - loop { - let enter = &events[enter_index]; - if enter.event_type == EventType::Enter && enter.token_type == token_type { - return Span { - // start: enter.point.clone(), - start_index: enter.index, - // end, - end_index, - // token_type, - }; - } - - enter_index -= 1; - } -} - -/// Serialize a span, optionally expanding tabs. -pub fn slice_serialize(codes: &[Code], span: &Span, expand_tabs: bool) -> String { - serialize_chunks(slice_codes(codes, span), expand_tabs) -} - -/// Get a slice of codes from a span. -pub fn slice_codes<'a>(codes: &'a [Code], span: &Span) -> &'a [Code] { - &codes[span.start_index..span.end_index] -} - -/// Serialize a slice of codes, optionally expanding tabs. -pub fn serialize_chunks(codes: &[Code], expand_tabs: bool) -> String { - let mut at_tab = false; - let mut index = 0; - let mut value: Vec<char> = vec![]; - - while index < codes.len() { - let code = codes[index]; - let mut at_tab_next = false; - - match code { - Code::CarriageReturnLineFeed => { - value.push('\r'); - value.push('\n'); - } - Code::Char(char) if char == '\n' || char == '\r' => { - value.push(char); - } - Code::Char(char) if char == '\t' => { - at_tab_next = true; - value.push(if expand_tabs { ' ' } else { char }); - } - Code::VirtualSpace => { - if !expand_tabs && at_tab { - index += 1; - continue; - } - value.push(' '); - } - Code::Char(char) => { - value.push(char); - } - Code::None => { - unreachable!("unexpected EOF code in codes"); - } - } - - at_tab = at_tab_next; - - index += 1; - } - - value.into_iter().collect() -} |