| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you under the Apache License, Version 2.0 (the |
| // "License"); you may not use this file except in compliance |
| // with the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, |
| // software distributed under the License is distributed on an |
| // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| // KIND, either express or implied. See the License for the |
| // specific language governing permissions and limitations |
| // under the License.. |
| |
| use core::convert::TryFrom; |
| use core::{char, fmt, iter, mem, str}; |
| |
| // Maximum recursion depth when parsing symbols before we just bail out saying |
| // "this symbol is invalid" |
| const MAX_DEPTH: u32 = 500; |
| |
| /// Representation of a demangled symbol name. |
| pub struct Demangle<'a> { |
| inner: &'a str, |
| } |
| |
| #[derive(PartialEq, Eq, Debug)] |
| pub enum ParseError { |
| /// Symbol doesn't match the expected `v0` grammar. |
| Invalid, |
| |
| /// Parsing the symbol crossed the recursion limit (see `MAX_DEPTH`). |
| RecursedTooDeep, |
| } |
| |
| /// De-mangles a Rust symbol into a more readable version |
| /// |
| /// This function will take a **mangled** symbol and return a value. When printed, |
| /// the de-mangled version will be written. If the symbol does not look like |
| /// a mangled symbol, the original value will be written instead. |
| pub fn demangle(s: &str) -> Result<(Demangle, &str), ParseError> { |
| // First validate the symbol. If it doesn't look like anything we're |
| // expecting, we just print it literally. Note that we must handle non-Rust |
| // symbols because we could have any function in the backtrace. |
| let inner; |
| if s.len() > 2 && s.starts_with("_R") { |
| inner = &s[2..]; |
| } else if s.len() > 1 && s.starts_with('R') { |
| // On Windows, dbghelp strips leading underscores, so we accept "R..." |
| // form too. |
| inner = &s[1..]; |
| } else if s.len() > 3 && s.starts_with("__R") { |
| // On OSX, symbols are prefixed with an extra _ |
| inner = &s[3..]; |
| } else { |
| return Err(ParseError::Invalid); |
| } |
| |
| // Paths always start with uppercase characters. |
| match inner.as_bytes()[0] { |
| b'A'..=b'Z' => {} |
| _ => return Err(ParseError::Invalid), |
| } |
| |
| // only work with ascii text |
| if inner.bytes().any(|c| c & 0x80 != 0) { |
| return Err(ParseError::Invalid); |
| } |
| |
| // Verify that the symbol is indeed a valid path. |
| let try_parse_path = |parser| { |
| let mut dummy_printer = Printer { |
| parser: Ok(parser), |
| out: None, |
| bound_lifetime_depth: 0, |
| }; |
| dummy_printer |
| .print_path(false) |
| .expect("`fmt::Error`s should be impossible without a `fmt::Formatter`"); |
| dummy_printer.parser |
| }; |
| let mut parser = Parser { |
| sym: inner, |
| next: 0, |
| depth: 0, |
| }; |
| parser = try_parse_path(parser)?; |
| |
| // Instantiating crate (paths always start with uppercase characters). |
| if let Some(&(b'A'..=b'Z')) = parser.sym.as_bytes().get(parser.next) { |
| parser = try_parse_path(parser)?; |
| } |
| |
| Ok((Demangle { inner }, &parser.sym[parser.next..])) |
| } |
| |
| impl<'s> fmt::Display for Demangle<'s> { |
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| let mut printer = Printer { |
| parser: Ok(Parser { |
| sym: self.inner, |
| next: 0, |
| depth: 0, |
| }), |
| out: Some(f), |
| bound_lifetime_depth: 0, |
| }; |
| printer.print_path(true) |
| } |
| } |
| |
| struct Ident<'s> { |
| /// ASCII part of the identifier. |
| ascii: &'s str, |
| /// Punycode insertion codes for Unicode codepoints, if any. |
| punycode: &'s str, |
| } |
| |
| const SMALL_PUNYCODE_LEN: usize = 128; |
| |
| impl<'s> Ident<'s> { |
| /// Attempt to decode punycode on the stack (allocation-free), |
| /// and pass the char slice to the closure, if successful. |
| /// This supports up to `SMALL_PUNYCODE_LEN` characters. |
| fn try_small_punycode_decode<F: FnOnce(&[char]) -> R, R>(&self, f: F) -> Option<R> { |
| let mut out = ['\0'; SMALL_PUNYCODE_LEN]; |
| let mut out_len = 0; |
| let r = self.punycode_decode(|i, c| { |
| // Check there's space left for another character. |
| out.get(out_len).ok_or(())?; |
| |
| // Move the characters after the insert position. |
| let mut j = out_len; |
| out_len += 1; |
| |
| while j > i { |
| out[j] = out[j - 1]; |
| j -= 1; |
| } |
| |
| // Insert the new character. |
| out[i] = c; |
| |
| Ok(()) |
| }); |
| if r.is_ok() { |
| Some(f(&out[..out_len])) |
| } else { |
| None |
| } |
| } |
| |
| /// Decode punycode as insertion positions and characters |
| /// and pass them to the closure, which can return `Err(())` |
| /// to stop the decoding process. |
| fn punycode_decode<F: FnMut(usize, char) -> Result<(), ()>>( |
| &self, |
| mut insert: F, |
| ) -> Result<(), ()> { |
| let mut punycode_bytes = self.punycode.bytes().peekable(); |
| if punycode_bytes.peek().is_none() { |
| return Err(()); |
| } |
| |
| let mut len = 0; |
| |
| // Populate initial output from ASCII fragment. |
| for c in self.ascii.chars() { |
| insert(len, c)?; |
| len += 1; |
| } |
| |
| // Punycode parameters and initial state. |
| let base = 36; |
| let t_min = 1; |
| let t_max = 26; |
| let skew = 38; |
| let mut damp = 700; |
| let mut bias = 72; |
| let mut i: usize = 0; |
| let mut n: usize = 0x80; |
| |
| loop { |
| // Read one delta value. |
| let mut delta: usize = 0; |
| let mut w = 1; |
| let mut k: usize = 0; |
| loop { |
| use core::cmp::{max, min}; |
| |
| k += base; |
| let t = min(max(k.saturating_sub(bias), t_min), t_max); |
| |
| let d = match punycode_bytes.next() { |
| Some(d @ b'a'..=b'z') => d - b'a', |
| Some(d @ b'0'..=b'9') => 26 + (d - b'0'), |
| _ => return Err(()), |
| }; |
| let d = d as usize; |
| delta = delta.checked_add(d.checked_mul(w).ok_or(())?).ok_or(())?; |
| if d < t { |
| break; |
| } |
| w = w.checked_mul(base - t).ok_or(())?; |
| } |
| |
| // Compute the new insert position and character. |
| len += 1; |
| i = i.checked_add(delta).ok_or(())?; |
| n = n.checked_add(i / len).ok_or(())?; |
| i %= len; |
| |
| let n_u32 = n as u32; |
| let c = if n_u32 as usize == n { |
| char::from_u32(n_u32).ok_or(())? |
| } else { |
| return Err(()); |
| }; |
| |
| // Insert the new character and increment the insert position. |
| insert(i, c)?; |
| i += 1; |
| |
| // If there are no more deltas, decoding is complete. |
| if punycode_bytes.peek().is_none() { |
| return Ok(()); |
| } |
| |
| // Perform bias adaptation. |
| delta /= damp; |
| damp = 2; |
| |
| delta += delta / len; |
| let mut k = 0; |
| while delta > ((base - t_min) * t_max) / 2 { |
| delta /= base - t_min; |
| k += base; |
| } |
| bias = k + ((base - t_min + 1) * delta) / (delta + skew); |
| } |
| } |
| } |
| |
| impl<'s> fmt::Display for Ident<'s> { |
| fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { |
| self.try_small_punycode_decode(|chars| { |
| for &c in chars { |
| c.fmt(f)?; |
| } |
| Ok(()) |
| }) |
| .unwrap_or_else(|| { |
| if !self.punycode.is_empty() { |
| f.write_str("punycode{")?; |
| |
| // Reconstruct a standard Punycode encoding, |
| // by using `-` as the separator. |
| if !self.ascii.is_empty() { |
| f.write_str(self.ascii)?; |
| f.write_str("-")?; |
| } |
| f.write_str(self.punycode)?; |
| |
| f.write_str("}") |
| } else { |
| f.write_str(self.ascii) |
| } |
| }) |
| } |
| } |
| |
| /// Sequence of lowercase hexadecimal nibbles (`0-9a-f`), used by leaf consts. |
| struct HexNibbles<'s> { |
| nibbles: &'s str, |
| } |
| |
| impl<'s> HexNibbles<'s> { |
| /// Decode an integer value (with the "most significant nibble" first), |
| /// returning `None` if it can't fit in an `u64`. |
| // FIXME(eddyb) should this "just" use `u128` instead? |
| fn try_parse_uint(&self) -> Option<u64> { |
| let nibbles = self.nibbles.trim_start_matches('0'); |
| |
| if nibbles.len() > 16 { |
| return None; |
| } |
| |
| let mut v = 0; |
| for nibble in nibbles.chars() { |
| v = (v << 4) | (nibble.to_digit(16).unwrap() as u64); |
| } |
| Some(v) |
| } |
| |
| /// Decode a UTF-8 byte sequence (with each byte using a pair of nibbles) |
| /// into individual `char`s, returning `None` for invalid UTF-8. |
| #[allow(clippy::needless_range_loop)] |
| fn try_parse_str_chars(&self) -> Option<impl Iterator<Item = char> + 's> { |
| if self.nibbles.len() % 2 != 0 { |
| return None; |
| } |
| |
| // FIXME(eddyb) use `array_chunks` instead, when that becomes stable. |
| let mut bytes = self |
| .nibbles |
| .as_bytes() |
| .chunks_exact(2) |
| .map(|slice| match slice { |
| [a, b] => [a, b], |
| _ => unreachable!(), |
| }) |
| .map(|[&hi, &lo]| { |
| let half = |nibble: u8| (nibble as char).to_digit(16).unwrap() as u8; |
| (half(hi) << 4) | half(lo) |
| }); |
| |
| let chars = iter::from_fn(move || { |
| // As long as there are any bytes left, there's at least one more |
| // UTF-8-encoded `char` to decode (or the possibility of error). |
| bytes.next().map(|first_byte| -> Result<char, ()> { |
| // FIXME(eddyb) this `enum` and `fn` should be somewhere in `core`. |
| enum Utf8FirstByteError { |
| ContinuationByte, |
| TooLong, |
| } |
| fn utf8_len_from_first_byte(byte: u8) -> Result<usize, Utf8FirstByteError> { |
| match byte { |
| 0x00..=0x7f => Ok(1), |
| 0x80..=0xbf => Err(Utf8FirstByteError::ContinuationByte), |
| 0xc0..=0xdf => Ok(2), |
| 0xe0..=0xef => Ok(3), |
| 0xf0..=0xf7 => Ok(4), |
| 0xf8..=0xff => Err(Utf8FirstByteError::TooLong), |
| } |
| } |
| |
| // Collect the appropriate amount of bytes (up to 4), according |
| // to the UTF-8 length implied by the first byte. |
| let utf8_len = utf8_len_from_first_byte(first_byte).map_err(|_| ())?; |
| let utf8 = &mut [first_byte, 0, 0, 0][..utf8_len]; |
| for i in 1..utf8_len { |
| utf8[i] = bytes.next().ok_or(())?; |
| } |
| |
| // Fully validate the UTF-8 sequence. |
| let s = str::from_utf8(utf8).map_err(|_| ())?; |
| |
| // Since we included exactly one UTF-8 sequence, and validation |
| // succeeded, `str::chars` should return exactly one `char`. |
| let mut chars = s.chars(); |
| match (chars.next(), chars.next()) { |
| (Some(c), None) => Ok(c), |
| _ => unreachable!( |
| "str::from_utf8({:?}) = {:?} was expected to have 1 char, \ |
| but {} chars were found", |
| utf8, |
| s, |
| s.chars().count() |
| ), |
| } |
| }) |
| }); |
| |
| // HACK(eddyb) doing a separate validation iteration like this might be |
| // wasteful, but it's easier to avoid starting to print a string literal |
| // in the first place, than to abort it mid-string. |
| if chars.clone().any(|r| r.is_err()) { |
| None |
| } else { |
| Some(chars.map(Result::unwrap)) |
| } |
| } |
| } |
| |
| fn basic_type(tag: u8) -> Option<&'static str> { |
| Some(match tag { |
| b'b' => "bool", |
| b'c' => "char", |
| b'e' => "str", |
| b'u' => "()", |
| b'a' => "i8", |
| b's' => "i16", |
| b'l' => "i32", |
| b'x' => "i64", |
| b'n' => "i128", |
| b'i' => "isize", |
| b'h' => "u8", |
| b't' => "u16", |
| b'm' => "u32", |
| b'y' => "u64", |
| b'o' => "u128", |
| b'j' => "usize", |
| b'f' => "f32", |
| b'd' => "f64", |
| b'z' => "!", |
| b'p' => "_", |
| b'v' => "...", |
| |
| _ => return None, |
| }) |
| } |
| |
| struct Parser<'s> { |
| sym: &'s str, |
| next: usize, |
| depth: u32, |
| } |
| |
| impl<'s> Parser<'s> { |
| fn push_depth(&mut self) -> Result<(), ParseError> { |
| self.depth += 1; |
| if self.depth > MAX_DEPTH { |
| Err(ParseError::RecursedTooDeep) |
| } else { |
| Ok(()) |
| } |
| } |
| |
| fn pop_depth(&mut self) { |
| self.depth -= 1; |
| } |
| |
| fn peek(&self) -> Option<u8> { |
| self.sym.as_bytes().get(self.next).cloned() |
| } |
| |
| fn eat(&mut self, b: u8) -> bool { |
| if self.peek() == Some(b) { |
| self.next += 1; |
| true |
| } else { |
| false |
| } |
| } |
| |
| fn next(&mut self) -> Result<u8, ParseError> { |
| let b = self.peek().ok_or(ParseError::Invalid)?; |
| self.next += 1; |
| Ok(b) |
| } |
| |
| fn hex_nibbles(&mut self) -> Result<HexNibbles<'s>, ParseError> { |
| let start = self.next; |
| loop { |
| match self.next()? { |
| b'0'..=b'9' | b'a'..=b'f' => {} |
| b'_' => break, |
| _ => return Err(ParseError::Invalid), |
| } |
| } |
| Ok(HexNibbles { |
| nibbles: &self.sym[start..self.next - 1], |
| }) |
| } |
| |
| fn digit_10(&mut self) -> Result<u8, ParseError> { |
| let d = match self.peek() { |
| Some(d @ b'0'..=b'9') => d - b'0', |
| _ => return Err(ParseError::Invalid), |
| }; |
| self.next += 1; |
| Ok(d) |
| } |
| |
| fn digit_62(&mut self) -> Result<u8, ParseError> { |
| let d = match self.peek() { |
| Some(d @ b'0'..=b'9') => d - b'0', |
| Some(d @ b'a'..=b'z') => 10 + (d - b'a'), |
| Some(d @ b'A'..=b'Z') => 10 + 26 + (d - b'A'), |
| _ => return Err(ParseError::Invalid), |
| }; |
| self.next += 1; |
| Ok(d) |
| } |
| |
| fn integer_62(&mut self) -> Result<u64, ParseError> { |
| if self.eat(b'_') { |
| return Ok(0); |
| } |
| |
| let mut x: u64 = 0; |
| while !self.eat(b'_') { |
| let d = self.digit_62()? as u64; |
| x = x.checked_mul(62).ok_or(ParseError::Invalid)?; |
| x = x.checked_add(d).ok_or(ParseError::Invalid)?; |
| } |
| x.checked_add(1).ok_or(ParseError::Invalid) |
| } |
| |
| fn opt_integer_62(&mut self, tag: u8) -> Result<u64, ParseError> { |
| if !self.eat(tag) { |
| return Ok(0); |
| } |
| self.integer_62()?.checked_add(1).ok_or(ParseError::Invalid) |
| } |
| |
| fn disambiguator(&mut self) -> Result<u64, ParseError> { |
| self.opt_integer_62(b's') |
| } |
| |
| fn namespace(&mut self) -> Result<Option<char>, ParseError> { |
| match self.next()? { |
| // Special namespaces, like closures and shims. |
| ns @ b'A'..=b'Z' => Ok(Some(ns as char)), |
| |
| // Implementation-specific/unspecified namespaces. |
| b'a'..=b'z' => Ok(None), |
| |
| _ => Err(ParseError::Invalid), |
| } |
| } |
| |
| fn backref(&mut self) -> Result<Parser<'s>, ParseError> { |
| let s_start = self.next - 1; |
| let i = self.integer_62()?; |
| if i >= s_start as u64 { |
| return Err(ParseError::Invalid); |
| } |
| let mut new_parser = Parser { |
| sym: self.sym, |
| next: i as usize, |
| depth: self.depth, |
| }; |
| new_parser.push_depth()?; |
| Ok(new_parser) |
| } |
| |
| fn ident(&mut self) -> Result<Ident<'s>, ParseError> { |
| let is_punycode = self.eat(b'u'); |
| let mut len = self.digit_10()? as usize; |
| if len != 0 { |
| while let Ok(d) = self.digit_10() { |
| len = len.checked_mul(10).ok_or(ParseError::Invalid)?; |
| len = len.checked_add(d as usize).ok_or(ParseError::Invalid)?; |
| } |
| } |
| |
| // Skip past the optional `_` separator. |
| self.eat(b'_'); |
| |
| let start = self.next; |
| self.next = self.next.checked_add(len).ok_or(ParseError::Invalid)?; |
| if self.next > self.sym.len() { |
| return Err(ParseError::Invalid); |
| } |
| |
| let ident = &self.sym[start..self.next]; |
| |
| if is_punycode { |
| let ident = match ident.bytes().rposition(|b| b == b'_') { |
| Some(i) => Ident { |
| ascii: &ident[..i], |
| punycode: &ident[i + 1..], |
| }, |
| None => Ident { |
| ascii: "", |
| punycode: ident, |
| }, |
| }; |
| if ident.punycode.is_empty() { |
| return Err(ParseError::Invalid); |
| } |
| Ok(ident) |
| } else { |
| Ok(Ident { |
| ascii: ident, |
| punycode: "", |
| }) |
| } |
| } |
| } |
| |
| struct Printer<'a, 'b: 'a, 's> { |
| /// The input parser to demangle from, or `Err` if any (parse) error was |
| /// encountered (in order to disallow further likely-incorrect demangling). |
| /// |
| /// See also the documentation on the `invalid!` and `parse!` macros below. |
| parser: Result<Parser<'s>, ParseError>, |
| |
| /// The output formatter to demangle to, or `None` while skipping printing. |
| out: Option<&'a mut fmt::Formatter<'b>>, |
| |
| /// Cumulative number of lifetimes bound by `for<...>` binders ('G'), |
| /// anywhere "around" the current entity (e.g. type) being demangled. |
| /// This value is not tracked while skipping printing, as it'd be unused. |
| /// |
| /// See also the documentation on the `Printer::in_binder` method. |
| bound_lifetime_depth: u32, |
| } |
| |
| impl ParseError { |
| /// Snippet to print when the error is initially encountered. |
| fn message(&self) -> &str { |
| match self { |
| ParseError::Invalid => "{invalid syntax}", |
| ParseError::RecursedTooDeep => "{recursion limit reached}", |
| } |
| } |
| } |
| |
| /// Mark the parser as errored (with `ParseError::Invalid`), print the |
| /// appropriate message (see `ParseError::message`) and return early. |
| macro_rules! invalid { |
| ($printer:ident) => {{ |
| let err = ParseError::Invalid; |
| $printer.print(err.message())?; |
| $printer.parser = Err(err); |
| return Ok(()); |
| }}; |
| } |
| |
| /// Call a parser method (if the parser hasn't errored yet), |
| /// and mark the parser as errored if it returns `Err`. |
| /// |
| /// If the parser errored, before or now, this returns early, |
| /// from the current function, after printing either: |
| /// * for a new error, the appropriate message (see `ParseError::message`) |
| /// * for an earlier error, only `?` - this allows callers to keep printing |
| /// the approximate syntax of the path/type/const, despite having errors, |
| /// e.g. `Vec<[(A, ?); ?]>` instead of `Vec<[(A, ?` |
| macro_rules! parse { |
| ($printer:ident, $method:ident $(($($arg:expr),*))*) => { |
| match $printer.parser { |
| Ok(ref mut parser) => match parser.$method($($($arg),*)*) { |
| Ok(x) => x, |
| Err(err) => { |
| $printer.print(err.message())?; |
| $printer.parser = Err(err); |
| return Ok(()); |
| } |
| } |
| Err(_) => return $printer.print("?"), |
| } |
| }; |
| } |
| |
| impl<'a, 'b, 's> Printer<'a, 'b, 's> { |
| /// Eat the given character from the parser, |
| /// returning `false` if the parser errored. |
| fn eat(&mut self, b: u8) -> bool { |
| self.parser.as_mut().map(|p| p.eat(b)) == Ok(true) |
| } |
| |
| /// Skip printing (i.e. `self.out` will be `None`) for the duration of the |
| /// given closure. This should not change parsing behavior, only disable the |
| /// output, but there may be optimizations (such as not traversing backrefs). |
| fn skipping_printing<F>(&mut self, f: F) |
| where |
| F: FnOnce(&mut Self) -> fmt::Result, |
| { |
| let orig_out = self.out.take(); |
| f(self).expect("`fmt::Error`s should be impossible without a `fmt::Formatter`"); |
| self.out = orig_out; |
| } |
| |
| /// Print the target of a backref, using the given closure. |
| /// When printing is being skipped, the backref will only be parsed, |
| /// ignoring the backref's target completely. |
| fn print_backref<F>(&mut self, f: F) -> fmt::Result |
| where |
| F: FnOnce(&mut Self) -> fmt::Result, |
| { |
| let backref_parser = parse!(self, backref); |
| |
| if self.out.is_none() { |
| return Ok(()); |
| } |
| |
| let orig_parser = mem::replace(&mut self.parser, Ok(backref_parser)); |
| let r = f(self); |
| self.parser = orig_parser; |
| r |
| } |
| |
| fn pop_depth(&mut self) { |
| if let Ok(ref mut parser) = self.parser { |
| parser.pop_depth(); |
| } |
| } |
| |
| /// Output the given value to `self.out` (using `fmt::Display` formatting), |
| /// if printing isn't being skipped. |
| fn print(&mut self, x: impl fmt::Display) -> fmt::Result { |
| if let Some(out) = &mut self.out { |
| fmt::Display::fmt(&x, out)?; |
| } |
| Ok(()) |
| } |
| |
| /// Output the given `char`s (escaped using `char::escape_debug`), with the |
| /// whole sequence wrapped in quotes, for either a `char` or `&str` literal, |
| /// if printing isn't being skipped. |
| fn print_quoted_escaped_chars( |
| &mut self, |
| quote: char, |
| chars: impl Iterator<Item = char>, |
| ) -> fmt::Result { |
| if let Some(out) = &mut self.out { |
| use core::fmt::Write; |
| |
| out.write_char(quote)?; |
| for c in chars { |
| // Special-case not escaping a single/double quote, when |
| // inside the opposite kind of quote. |
| if matches!((quote, c), ('\'', '"') | ('"', '\'')) { |
| out.write_char(c)?; |
| continue; |
| } |
| |
| for escaped in c.escape_debug() { |
| out.write_char(escaped)?; |
| } |
| } |
| out.write_char(quote)?; |
| } |
| Ok(()) |
| } |
| |
| /// Print the lifetime according to the previously decoded index. |
| /// An index of `0` always refers to `'_`, but starting with `1`, |
| /// indices refer to late-bound lifetimes introduced by a binder. |
| fn print_lifetime_from_index(&mut self, lt: u64) -> fmt::Result { |
| // Bound lifetimes aren't tracked when skipping printing. |
| if self.out.is_none() { |
| return Ok(()); |
| } |
| |
| self.print("'")?; |
| if lt == 0 { |
| return self.print("_"); |
| } |
| match (self.bound_lifetime_depth as u64).checked_sub(lt) { |
| Some(depth) => { |
| // Try to print lifetimes alphabetically first. |
| if depth < 26 { |
| let c = (b'a' + depth as u8) as char; |
| self.print(c) |
| } else { |
| // Use `'_123` after running out of letters. |
| self.print("_")?; |
| self.print(depth) |
| } |
| } |
| None => invalid!(self), |
| } |
| } |
| |
| /// Optionally enter a binder ('G') for late-bound lifetimes, |
| /// printing e.g. `for<'a, 'b> ` before calling the closure, |
| /// and make those lifetimes visible to it (via depth level). |
| fn in_binder<F>(&mut self, f: F) -> fmt::Result |
| where |
| F: FnOnce(&mut Self) -> fmt::Result, |
| { |
| let bound_lifetimes = parse!(self, opt_integer_62(b'G')); |
| |
| // Don't track bound lifetimes when skipping printing. |
| if self.out.is_none() { |
| return f(self); |
| } |
| |
| if bound_lifetimes > 0 { |
| self.print("for<")?; |
| for i in 0..bound_lifetimes { |
| if i > 0 { |
| self.print(", ")?; |
| } |
| self.bound_lifetime_depth += 1; |
| self.print_lifetime_from_index(1)?; |
| } |
| self.print("> ")?; |
| } |
| |
| let r = f(self); |
| |
| // Restore `bound_lifetime_depth` to the previous value. |
| self.bound_lifetime_depth -= bound_lifetimes as u32; |
| |
| r |
| } |
| |
| /// Print list elements using the given closure and separator, |
| /// until the end of the list ('E') is found, or the parser errors. |
| /// Returns the number of elements printed. |
| fn print_sep_list<F>(&mut self, f: F, sep: &str) -> Result<usize, fmt::Error> |
| where |
| F: Fn(&mut Self) -> fmt::Result, |
| { |
| let mut i = 0; |
| while self.parser.is_ok() && !self.eat(b'E') { |
| if i > 0 { |
| self.print(sep)?; |
| } |
| f(self)?; |
| i += 1; |
| } |
| Ok(i) |
| } |
| |
| fn print_path(&mut self, in_value: bool) -> fmt::Result { |
| parse!(self, push_depth); |
| |
| let tag = parse!(self, next); |
| match tag { |
| b'C' => { |
| let dis = parse!(self, disambiguator); |
| let name = parse!(self, ident); |
| |
| self.print(name)?; |
| if let Some(out) = &mut self.out { |
| if !out.alternate() { |
| out.write_str("[")?; |
| fmt::LowerHex::fmt(&dis, out)?; |
| out.write_str("]")?; |
| } |
| } |
| } |
| b'N' => { |
| let ns = parse!(self, namespace); |
| |
| self.print_path(in_value)?; |
| |
| // HACK(eddyb) if the parser is already marked as having errored, |
| // `parse!` below will print a `?` without its preceding `::` |
| // (because printing the `::` is skipped in certain conditions, |
| // i.e. a lowercase namespace with an empty identifier), |
| // so in order to get `::?`, the `::` has to be printed here. |
| if self.parser.is_err() { |
| self.print("::")?; |
| } |
| |
| let dis = parse!(self, disambiguator); |
| let name = parse!(self, ident); |
| |
| match ns { |
| // Special namespaces, like closures and shims. |
| Some(ns) => { |
| self.print("::{")?; |
| match ns { |
| 'C' => self.print("closure")?, |
| 'S' => self.print("shim")?, |
| _ => self.print(ns)?, |
| } |
| if !name.ascii.is_empty() || !name.punycode.is_empty() { |
| self.print(":")?; |
| self.print(name)?; |
| } |
| self.print("#")?; |
| self.print(dis)?; |
| self.print("}")?; |
| } |
| |
| // Implementation-specific/unspecified namespaces. |
| None => { |
| if !name.ascii.is_empty() || !name.punycode.is_empty() { |
| self.print("::")?; |
| self.print(name)?; |
| } |
| } |
| } |
| } |
| b'M' | b'X' | b'Y' => { |
| if tag != b'Y' { |
| // Ignore the `impl`'s own path. |
| parse!(self, disambiguator); |
| self.skipping_printing(|this| this.print_path(false)); |
| } |
| |
| self.print("<")?; |
| self.print_type()?; |
| if tag != b'M' { |
| self.print(" as ")?; |
| self.print_path(false)?; |
| } |
| self.print(">")?; |
| } |
| b'I' => { |
| self.print_path(in_value)?; |
| if in_value { |
| self.print("::")?; |
| } |
| self.print("<")?; |
| self.print_sep_list(Self::print_generic_arg, ", ")?; |
| self.print(">")?; |
| } |
| b'B' => { |
| self.print_backref(|this| this.print_path(in_value))?; |
| } |
| _ => invalid!(self), |
| } |
| |
| self.pop_depth(); |
| Ok(()) |
| } |
| |
| fn print_generic_arg(&mut self) -> fmt::Result { |
| if self.eat(b'L') { |
| let lt = parse!(self, integer_62); |
| self.print_lifetime_from_index(lt) |
| } else if self.eat(b'K') { |
| self.print_const(false) |
| } else { |
| self.print_type() |
| } |
| } |
| |
| fn print_type(&mut self) -> fmt::Result { |
| let tag = parse!(self, next); |
| |
| if let Some(ty) = basic_type(tag) { |
| return self.print(ty); |
| } |
| |
| parse!(self, push_depth); |
| |
| match tag { |
| b'R' | b'Q' => { |
| self.print("&")?; |
| if self.eat(b'L') { |
| let lt = parse!(self, integer_62); |
| if lt != 0 { |
| self.print_lifetime_from_index(lt)?; |
| self.print(" ")?; |
| } |
| } |
| if tag != b'R' { |
| self.print("mut ")?; |
| } |
| self.print_type()?; |
| } |
| |
| b'P' | b'O' => { |
| self.print("*")?; |
| if tag != b'P' { |
| self.print("mut ")?; |
| } else { |
| self.print("const ")?; |
| } |
| self.print_type()?; |
| } |
| |
| b'A' | b'S' => { |
| self.print("[")?; |
| self.print_type()?; |
| if tag == b'A' { |
| self.print("; ")?; |
| self.print_const(true)?; |
| } |
| self.print("]")?; |
| } |
| b'T' => { |
| self.print("(")?; |
| let count = self.print_sep_list(Self::print_type, ", ")?; |
| if count == 1 { |
| self.print(",")?; |
| } |
| self.print(")")?; |
| } |
| b'F' => self.in_binder(|this| { |
| let is_unsafe = this.eat(b'U'); |
| let abi = if this.eat(b'K') { |
| if this.eat(b'C') { |
| Some("C") |
| } else { |
| let abi = parse!(this, ident); |
| if abi.ascii.is_empty() || !abi.punycode.is_empty() { |
| invalid!(this); |
| } |
| Some(abi.ascii) |
| } |
| } else { |
| None |
| }; |
| |
| if is_unsafe { |
| this.print("unsafe ")?; |
| } |
| |
| if let Some(abi) = abi { |
| this.print("extern \"")?; |
| |
| // If the ABI had any `-`, they were replaced with `_`, |
| // so the parts between `_` have to be re-joined with `-`. |
| let mut parts = abi.split('_'); |
| this.print(parts.next().unwrap())?; |
| for part in parts { |
| this.print("-")?; |
| this.print(part)?; |
| } |
| |
| this.print("\" ")?; |
| } |
| |
| this.print("fn(")?; |
| this.print_sep_list(Self::print_type, ", ")?; |
| this.print(")")?; |
| |
| if this.eat(b'u') { |
| // Skip printing the return type if it's 'u', i.e. `()`. |
| } else { |
| this.print(" -> ")?; |
| this.print_type()?; |
| } |
| |
| Ok(()) |
| })?, |
| b'D' => { |
| self.print("dyn ")?; |
| self.in_binder(|this| { |
| this.print_sep_list(Self::print_dyn_trait, " + ")?; |
| Ok(()) |
| })?; |
| |
| if !self.eat(b'L') { |
| invalid!(self); |
| } |
| let lt = parse!(self, integer_62); |
| if lt != 0 { |
| self.print(" + ")?; |
| self.print_lifetime_from_index(lt)?; |
| } |
| } |
| b'B' => { |
| self.print_backref(Self::print_type)?; |
| } |
| _ => { |
| // Go back to the tag, so `print_path` also sees it. |
| let _ = self.parser.as_mut().map(|p| p.next -= 1); |
| self.print_path(false)?; |
| } |
| } |
| |
| self.pop_depth(); |
| Ok(()) |
| } |
| |
| /// A trait in a trait object may have some "existential projections" |
| /// (i.e. associated type bindings) after it, which should be printed |
| /// in the `<...>` of the trait, e.g. `dyn Trait<T, U, Assoc=X>`. |
| /// To this end, this method will keep the `<...>` of an 'I' path |
| /// open, by omitting the `>`, and return `Ok(true)` in that case. |
| fn print_path_maybe_open_generics(&mut self) -> Result<bool, fmt::Error> { |
| if self.eat(b'B') { |
| // NOTE(eddyb) the closure may not run if printing is being skipped, |
| // but in that case the returned boolean doesn't matter. |
| let mut open = false; |
| self.print_backref(|this| { |
| open = this.print_path_maybe_open_generics()?; |
| Ok(()) |
| })?; |
| Ok(open) |
| } else if self.eat(b'I') { |
| self.print_path(false)?; |
| self.print("<")?; |
| self.print_sep_list(Self::print_generic_arg, ", ")?; |
| Ok(true) |
| } else { |
| self.print_path(false)?; |
| Ok(false) |
| } |
| } |
| |
| fn print_dyn_trait(&mut self) -> fmt::Result { |
| let mut open = self.print_path_maybe_open_generics()?; |
| |
| while self.eat(b'p') { |
| if !open { |
| self.print("<")?; |
| open = true; |
| } else { |
| self.print(", ")?; |
| } |
| |
| let name = parse!(self, ident); |
| self.print(name)?; |
| self.print(" = ")?; |
| self.print_type()?; |
| } |
| |
| if open { |
| self.print(">")?; |
| } |
| |
| Ok(()) |
| } |
| |
| fn print_const(&mut self, in_value: bool) -> fmt::Result { |
| let tag = parse!(self, next); |
| |
| parse!(self, push_depth); |
| |
| // Only literals (and the names of `const` generic parameters, but they |
| // don't get mangled at all), can appear in generic argument position |
| // without any disambiguation, all other expressions require braces. |
| // To avoid duplicating the mapping between `tag` and what syntax gets |
| // used (especially any special-casing), every case that needs braces |
| // has to call `open_brace(self)?` (and the closing brace is automatic). |
| let mut opened_brace = false; |
| let mut open_brace_if_outside_expr = |this: &mut Self| { |
| // If this expression is nested in another, braces aren't required. |
| if in_value { |
| return Ok(()); |
| } |
| |
| opened_brace = true; |
| this.print("{") |
| }; |
| |
| match tag { |
| b'p' => self.print("_")?, |
| |
| // Primitive leaves with hex-encoded values (see `basic_type`). |
| b'h' | b't' | b'm' | b'y' | b'o' | b'j' => self.print_const_uint(tag)?, |
| b'a' | b's' | b'l' | b'x' | b'n' | b'i' => { |
| if self.eat(b'n') { |
| self.print("-")?; |
| } |
| |
| self.print_const_uint(tag)?; |
| } |
| b'b' => match parse!(self, hex_nibbles).try_parse_uint() { |
| Some(0) => self.print("false")?, |
| Some(1) => self.print("true")?, |
| _ => invalid!(self), |
| }, |
| b'c' => { |
| let valid_char = parse!(self, hex_nibbles) |
| .try_parse_uint() |
| .and_then(|v| u32::try_from(v).ok()) |
| .and_then(char::from_u32); |
| match valid_char { |
| Some(c) => self.print_quoted_escaped_chars('\'', iter::once(c))?, |
| None => invalid!(self), |
| } |
| } |
| b'e' => { |
| // NOTE(eddyb) a string literal `"..."` has type `&str`, so |
| // to get back the type `str`, `*"..."` syntax is needed |
| // (even if that may not be valid in Rust itself). |
| open_brace_if_outside_expr(self)?; |
| self.print("*")?; |
| |
| self.print_const_str_literal()?; |
| } |
| |
| b'R' | b'Q' => { |
| // NOTE(eddyb) this prints `"..."` instead of `&*"..."`, which |
| // is what `Re..._` would imply (see comment for `str` above). |
| if tag == b'R' && self.eat(b'e') { |
| self.print_const_str_literal()?; |
| } else { |
| open_brace_if_outside_expr(self)?; |
| self.print("&")?; |
| if tag != b'R' { |
| self.print("mut ")?; |
| } |
| self.print_const(true)?; |
| } |
| } |
| b'A' => { |
| open_brace_if_outside_expr(self)?; |
| self.print("[")?; |
| self.print_sep_list(|this| this.print_const(true), ", ")?; |
| self.print("]")?; |
| } |
| b'T' => { |
| open_brace_if_outside_expr(self)?; |
| self.print("(")?; |
| let count = self.print_sep_list(|this| this.print_const(true), ", ")?; |
| if count == 1 { |
| self.print(",")?; |
| } |
| self.print(")")?; |
| } |
| b'V' => { |
| open_brace_if_outside_expr(self)?; |
| self.print_path(true)?; |
| match parse!(self, next) { |
| b'U' => {} |
| b'T' => { |
| self.print("(")?; |
| self.print_sep_list(|this| this.print_const(true), ", ")?; |
| self.print(")")?; |
| } |
| b'S' => { |
| self.print(" { ")?; |
| self.print_sep_list( |
| |this| { |
| parse!(this, disambiguator); |
| let name = parse!(this, ident); |
| this.print(name)?; |
| this.print(": ")?; |
| this.print_const(true) |
| }, |
| ", ", |
| )?; |
| self.print(" }")?; |
| } |
| _ => invalid!(self), |
| } |
| } |
| b'B' => { |
| self.print_backref(|this| this.print_const(in_value))?; |
| } |
| _ => invalid!(self), |
| } |
| |
| if opened_brace { |
| self.print("}")?; |
| } |
| |
| self.pop_depth(); |
| Ok(()) |
| } |
| |
| fn print_const_uint(&mut self, ty_tag: u8) -> fmt::Result { |
| let hex = parse!(self, hex_nibbles); |
| |
| match hex.try_parse_uint() { |
| Some(v) => self.print(v)?, |
| |
| // Print anything that doesn't fit in `u64` verbatim. |
| None => { |
| self.print("0x")?; |
| self.print(hex.nibbles)?; |
| } |
| } |
| |
| if let Some(out) = &mut self.out { |
| if !out.alternate() { |
| let ty = basic_type(ty_tag).unwrap(); |
| self.print(ty)?; |
| } |
| } |
| |
| Ok(()) |
| } |
| |
| fn print_const_str_literal(&mut self) -> fmt::Result { |
| match parse!(self, hex_nibbles).try_parse_str_chars() { |
| Some(chars) => self.print_quoted_escaped_chars('"', chars), |
| None => invalid!(self), |
| } |
| } |
| } |