From 9b5bbab104d8ba445143f6f3a9e4149b40c29ae5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Adolfo=20Ochagav=C3=ADa?= Date: Sun, 4 Nov 2018 15:06:38 +0100 Subject: Add character literal parsing and validation --- crates/ra_syntax/src/string_lexing/mod.rs | 311 ++++++++++++++++++++++++++++++ 1 file changed, 311 insertions(+) create mode 100644 crates/ra_syntax/src/string_lexing/mod.rs (limited to 'crates/ra_syntax/src/string_lexing') diff --git a/crates/ra_syntax/src/string_lexing/mod.rs b/crates/ra_syntax/src/string_lexing/mod.rs new file mode 100644 index 000000000..6b52c62c3 --- /dev/null +++ b/crates/ra_syntax/src/string_lexing/mod.rs @@ -0,0 +1,311 @@ +use self::CharComponentKind::*; +use rowan::{TextRange, TextUnit}; + +pub fn parse_char_literal(src: &str) -> CharComponentIterator { + CharComponentIterator { + parser: Parser::new(src), + has_closing_quote: false, + } +} + +#[derive(Debug, Eq, PartialEq, Clone)] +pub struct CharComponent { + pub range: TextRange, + pub kind: CharComponentKind, +} + +impl CharComponent { + fn new(range: TextRange, kind: CharComponentKind) -> CharComponent { + CharComponent { range, kind } + } +} + +#[derive(Debug, Eq, PartialEq, Clone)] +pub enum CharComponentKind { + CodePoint, + AsciiEscape, + AsciiCodeEscape, + UnicodeEscape, +} + +pub struct CharComponentIterator<'a> { + parser: Parser<'a>, + pub has_closing_quote: bool, +} + +impl<'a> Iterator for CharComponentIterator<'a> { + type Item = CharComponent; + fn next(&mut self) -> Option { + if self.parser.pos == 0 { + assert!( + self.parser.advance() == '\'', + "char literal should start with a quote" + ); + } + + if let Some(component) = self.parser.parse_char_component() { + return Some(component); + } + + // We get here when there are no char components left to parse + if self.parser.peek() == Some('\'') { + self.parser.advance(); + self.has_closing_quote = true; + } + + assert!( + self.parser.peek() == None, + "char literal should leave no unparsed input: src = {}, pos = {}, length = {}", + self.parser.src, + self.parser.pos, + self.parser.src.len() + ); + + None + } +} + +pub struct Parser<'a> { + src: &'a str, + pos: usize, +} + +impl<'a> Parser<'a> { + pub fn new(src: &'a str) -> Parser<'a> { + Parser { src, pos: 0 } + } + + // Utility methods + + pub fn peek(&self) -> Option { + if self.pos == self.src.len() { + return None; + } + + self.src[self.pos..].chars().next() + } + + pub fn advance(&mut self) -> char { + let next = self + .peek() + .expect("cannot advance if end of input is reached"); + self.pos += next.len_utf8(); + next + } + + pub fn get_pos(&self) -> TextUnit { + (self.pos as u32).into() + } + + // Char parsing methods + + fn parse_unicode_escape(&mut self, start: TextUnit) -> CharComponent { + // Note: validation of UnicodeEscape will be done elsewhere: + // * Only hex digits or underscores allowed + // * Max 6 chars + // * Within allowed range (must be at most 10FFFF) + match self.peek() { + Some('{') => { + self.advance(); + + // Parse anything until we reach `}` + while let Some(next) = self.peek() { + self.advance(); + if next == '}' { + break; + } + } + + let end = self.get_pos(); + CharComponent::new(TextRange::from_to(start, end), UnicodeEscape) + } + Some(_) | None => { + let end = self.get_pos(); + CharComponent::new(TextRange::from_to(start, end), UnicodeEscape) + } + } + } + + fn parse_ascii_code_escape(&mut self, start: TextUnit) -> CharComponent { + // Note: validation of AsciiCodeEscape will be done elsewhere: + // * First digit is octal + // * Second digit is hex + let code_start = self.get_pos(); + while let Some(next) = self.peek() { + if next == '\'' || (self.get_pos() - code_start == 2.into()) { + break; + } + + self.advance(); + } + + let end = self.get_pos(); + CharComponent::new(TextRange::from_to(start, end), AsciiCodeEscape) + } + + fn parse_escape(&mut self, start: TextUnit) -> CharComponent { + // Note: validation of AsciiEscape will be done elsewhere: + // * The escape sequence is non-empty + // * The escape sequence is valid + if self.peek().is_none() { + return CharComponent::new(TextRange::from_to(start, start), AsciiEscape); + } + + let next = self.advance(); + let end = self.get_pos(); + let range = TextRange::from_to(start, end); + match next { + 'x' => self.parse_ascii_code_escape(start), + 'u' => self.parse_unicode_escape(start), + _ => CharComponent::new(range, AsciiEscape), + } + } + + pub fn parse_char_component(&mut self) -> Option { + let next = self.peek()?; + + // Ignore character close + if next == '\'' { + return None; + } + + let start = self.get_pos(); + self.advance(); + + if next == '\\' { + Some(self.parse_escape(start)) + } else { + let end = self.get_pos(); + Some(CharComponent::new( + TextRange::from_to(start, end), + CodePoint, + )) + } + } +} + +#[cfg(test)] +mod tests { + use super::*; + + fn parse(src: &str) -> (bool, Vec) { + let component_iterator = &mut super::parse_char_literal(src); + let components: Vec<_> = component_iterator.collect(); + (component_iterator.has_closing_quote, components) + } + + fn unclosed_char_component(src: &str) -> CharComponent { + let (has_closing_quote, components) = parse(src); + assert!(!has_closing_quote, "char should not have closing quote"); + assert!(components.len() == 1); + components[0].clone() + } + + fn closed_char_component(src: &str) -> CharComponent { + let (has_closing_quote, components) = parse(src); + assert!(has_closing_quote, "char should have closing quote"); + assert!( + components.len() == 1, + "Literal: {}\nComponents: {:#?}", + src, + components + ); + components[0].clone() + } + + fn closed_char_components(src: &str) -> Vec { + let (has_closing_quote, components) = parse(src); + assert!(has_closing_quote, "char should have closing quote"); + components + } + + fn range_closed(src: &str) -> TextRange { + TextRange::from_to(1.into(), (src.len() as u32 - 1).into()) + } + + fn range_unclosed(src: &str) -> TextRange { + TextRange::from_to(1.into(), (src.len() as u32).into()) + } + + #[test] + fn test_unicode_escapes() { + let unicode_escapes = &[r"{DEAD}", "{BEEF}", "{FF}", ""]; + for escape in unicode_escapes { + let escape_sequence = format!(r"'\u{}'", escape); + let component = closed_char_component(&escape_sequence); + let expected_range = range_closed(&escape_sequence); + assert_eq!(component.kind, CharComponentKind::UnicodeEscape); + assert_eq!(component.range, expected_range); + } + } + + #[test] + fn test_unicode_escapes_unclosed() { + let unicode_escapes = &["{DEAD", "{BEEF", "{FF"]; + for escape in unicode_escapes { + let escape_sequence = format!(r"'\u{}'", escape); + let component = unclosed_char_component(&escape_sequence); + let expected_range = range_unclosed(&escape_sequence); + assert_eq!(component.kind, CharComponentKind::UnicodeEscape); + assert_eq!(component.range, expected_range); + } + } + + #[test] + fn test_empty_char() { + let (has_closing_quote, components) = parse("''"); + assert!(has_closing_quote, "char should have closing quote"); + assert!(components.len() == 0); + } + + #[test] + fn test_unclosed_char() { + let component = unclosed_char_component("'a"); + assert!(component.kind == CodePoint); + assert!(component.range == TextRange::from_to(1.into(), 2.into())); + } + + #[test] + fn test_digit_escapes() { + let literals = &[r"", r"5", r"55"]; + + for literal in literals { + let lit_text = format!(r"'\x{}'", literal); + let component = closed_char_component(&lit_text); + assert!(component.kind == CharComponentKind::AsciiCodeEscape); + assert!(component.range == range_closed(&lit_text)); + } + + // More than 2 digits starts a new codepoint + let components = closed_char_components(r"'\x555'"); + assert!(components.len() == 2); + assert!(components[1].kind == CharComponentKind::CodePoint); + } + + #[test] + fn test_ascii_escapes() { + let literals = &[ + r"\'", "\\\"", // equivalent to \" + r"\n", r"\r", r"\t", r"\\", r"\0", + ]; + + for literal in literals { + let lit_text = format!("'{}'", literal); + let component = closed_char_component(&lit_text); + assert!(component.kind == CharComponentKind::AsciiEscape); + assert!(component.range == range_closed(&lit_text)); + } + } + + #[test] + fn test_no_escapes() { + let literals = &['"', 'n', 'r', 't', '0', 'x', 'u']; + + for &literal in literals { + let lit_text = format!("'{}'", literal); + let component = closed_char_component(&lit_text); + assert!(component.kind == CharComponentKind::CodePoint); + assert!(component.range == range_closed(&lit_text)); + } + } +} -- cgit v1.2.3