| //! Types for tracking pieces of source code within a crate. |
| //! |
| //! The [`SourceMap`] tracks all the source code used within a single crate, mapping |
| //! from integer byte positions to the original source code location. Each bit |
| //! of source parsed during crate parsing (typically files, in-memory strings, |
| //! or various bits of macro expansion) cover a continuous range of bytes in the |
| //! `SourceMap` and are represented by [`SourceFile`]s. Byte positions are stored in |
| //! [`Span`] and used pervasively in the compiler. They are absolute positions |
| //! within the `SourceMap`, which upon request can be converted to line and column |
| //! information, source code snippets, etc. |
| |
| pub use crate::hygiene::{ExpnData, ExpnKind}; |
| pub use crate::*; |
| |
| use rustc_data_structures::fx::FxHashMap; |
| use rustc_data_structures::stable_hasher::StableHasher; |
| use rustc_data_structures::sync::{AtomicU32, Lrc, MappedReadGuard, ReadGuard, RwLock}; |
| use std::hash::Hash; |
| use std::path::{Path, PathBuf}; |
| use std::sync::atomic::Ordering; |
| use std::{clone::Clone, cmp}; |
| use std::{convert::TryFrom, unreachable}; |
| |
| use std::fs; |
| use std::io; |
| use tracing::debug; |
| |
| #[cfg(test)] |
| mod tests; |
| |
| /// Returns the span itself if it doesn't come from a macro expansion, |
| /// otherwise return the call site span up to the `enclosing_sp` by |
| /// following the `expn_data` chain. |
| pub fn original_sp(sp: Span, enclosing_sp: Span) -> Span { |
| let expn_data1 = sp.ctxt().outer_expn_data(); |
| let expn_data2 = enclosing_sp.ctxt().outer_expn_data(); |
| if expn_data1.is_root() || !expn_data2.is_root() && expn_data1.call_site == expn_data2.call_site |
| { |
| sp |
| } else { |
| original_sp(expn_data1.call_site, enclosing_sp) |
| } |
| } |
| |
| pub mod monotonic { |
| use std::ops::{Deref, DerefMut}; |
| |
| /// A `MonotonicVec` is a `Vec` which can only be grown. |
| /// Once inserted, an element can never be removed or swapped, |
| /// guaranteeing that any indices into a `MonotonicVec` are stable |
| // This is declared in its own module to ensure that the private |
| // field is inaccessible |
| pub struct MonotonicVec<T>(Vec<T>); |
| impl<T> MonotonicVec<T> { |
| pub fn new(val: Vec<T>) -> MonotonicVec<T> { |
| MonotonicVec(val) |
| } |
| |
| pub fn push(&mut self, val: T) { |
| self.0.push(val); |
| } |
| } |
| |
| impl<T> Default for MonotonicVec<T> { |
| fn default() -> Self { |
| MonotonicVec::new(vec![]) |
| } |
| } |
| |
| impl<T> Deref for MonotonicVec<T> { |
| type Target = Vec<T>; |
| fn deref(&self) -> &Self::Target { |
| &self.0 |
| } |
| } |
| |
| impl<T> !DerefMut for MonotonicVec<T> {} |
| } |
| |
| #[derive(Clone, Encodable, Decodable, Debug, Copy, HashStable_Generic)] |
| pub struct Spanned<T> { |
| pub node: T, |
| pub span: Span, |
| } |
| |
| pub fn respan<T>(sp: Span, t: T) -> Spanned<T> { |
| Spanned { node: t, span: sp } |
| } |
| |
| pub fn dummy_spanned<T>(t: T) -> Spanned<T> { |
| respan(DUMMY_SP, t) |
| } |
| |
| // _____________________________________________________________________________ |
| // SourceFile, MultiByteChar, FileName, FileLines |
| // |
| |
| /// An abstraction over the fs operations used by the Parser. |
| pub trait FileLoader { |
| /// Query the existence of a file. |
| fn file_exists(&self, path: &Path) -> bool; |
| |
| /// Read the contents of a UTF-8 file into memory. |
| fn read_file(&self, path: &Path) -> io::Result<String>; |
| } |
| |
| /// A FileLoader that uses std::fs to load real files. |
| pub struct RealFileLoader; |
| |
| impl FileLoader for RealFileLoader { |
| fn file_exists(&self, path: &Path) -> bool { |
| path.exists() |
| } |
| |
| fn read_file(&self, path: &Path) -> io::Result<String> { |
| fs::read_to_string(path) |
| } |
| } |
| |
| /// This is a [SourceFile] identifier that is used to correlate source files between |
| /// subsequent compilation sessions (which is something we need to do during |
| /// incremental compilation). |
| /// |
| /// The [StableSourceFileId] also contains the CrateNum of the crate the source |
| /// file was originally parsed for. This way we get two separate entries in |
| /// the [SourceMap] if the same file is part of both the local and an upstream |
| /// crate. Trying to only have one entry for both cases is problematic because |
| /// at the point where we discover that there's a local use of the file in |
| /// addition to the upstream one, we might already have made decisions based on |
| /// the assumption that it's an upstream file. Treating the two files as |
| /// different has no real downsides. |
| #[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)] |
| pub struct StableSourceFileId { |
| // A hash of the source file's FileName. This is hash so that it's size |
| // is more predictable than if we included the actual FileName value. |
| pub file_name_hash: u64, |
| |
| // The CrateNum of the crate this source file was originally parsed for. |
| // We cannot include this information in the hash because at the time |
| // of hashing we don't have the context to map from the CrateNum's numeric |
| // value to a StableCrateId. |
| pub cnum: CrateNum, |
| } |
| |
| // FIXME: we need a more globally consistent approach to the problem solved by |
| // StableSourceFileId, perhaps built atop source_file.name_hash. |
| impl StableSourceFileId { |
| pub fn new(source_file: &SourceFile) -> StableSourceFileId { |
| StableSourceFileId::new_from_name(&source_file.name, source_file.cnum) |
| } |
| |
| fn new_from_name(name: &FileName, cnum: CrateNum) -> StableSourceFileId { |
| let mut hasher = StableHasher::new(); |
| name.hash(&mut hasher); |
| StableSourceFileId { file_name_hash: hasher.finish(), cnum } |
| } |
| } |
| |
| // _____________________________________________________________________________ |
| // SourceMap |
| // |
| |
| #[derive(Default)] |
| pub(super) struct SourceMapFiles { |
| source_files: monotonic::MonotonicVec<Lrc<SourceFile>>, |
| stable_id_to_source_file: FxHashMap<StableSourceFileId, Lrc<SourceFile>>, |
| } |
| |
| pub struct SourceMap { |
| /// The address space below this value is currently used by the files in the source map. |
| used_address_space: AtomicU32, |
| |
| files: RwLock<SourceMapFiles>, |
| file_loader: Box<dyn FileLoader + Sync + Send>, |
| // This is used to apply the file path remapping as specified via |
| // `--remap-path-prefix` to all `SourceFile`s allocated within this `SourceMap`. |
| path_mapping: FilePathMapping, |
| |
| /// The algorithm used for hashing the contents of each source file. |
| hash_kind: SourceFileHashAlgorithm, |
| } |
| |
| impl SourceMap { |
| pub fn new(path_mapping: FilePathMapping) -> SourceMap { |
| Self::with_file_loader_and_hash_kind( |
| Box::new(RealFileLoader), |
| path_mapping, |
| SourceFileHashAlgorithm::Md5, |
| ) |
| } |
| |
| pub fn with_file_loader_and_hash_kind( |
| file_loader: Box<dyn FileLoader + Sync + Send>, |
| path_mapping: FilePathMapping, |
| hash_kind: SourceFileHashAlgorithm, |
| ) -> SourceMap { |
| SourceMap { |
| used_address_space: AtomicU32::new(0), |
| files: Default::default(), |
| file_loader, |
| path_mapping, |
| hash_kind, |
| } |
| } |
| |
| pub fn path_mapping(&self) -> &FilePathMapping { |
| &self.path_mapping |
| } |
| |
| pub fn file_exists(&self, path: &Path) -> bool { |
| self.file_loader.file_exists(path) |
| } |
| |
| pub fn load_file(&self, path: &Path) -> io::Result<Lrc<SourceFile>> { |
| let src = self.file_loader.read_file(path)?; |
| let filename = path.to_owned().into(); |
| Ok(self.new_source_file(filename, src)) |
| } |
| |
| /// Loads source file as a binary blob. |
| /// |
| /// Unlike `load_file`, guarantees that no normalization like BOM-removal |
| /// takes place. |
| pub fn load_binary_file(&self, path: &Path) -> io::Result<Vec<u8>> { |
| // Ideally, this should use `self.file_loader`, but it can't |
| // deal with binary files yet. |
| let bytes = fs::read(path)?; |
| |
| // We need to add file to the `SourceMap`, so that it is present |
| // in dep-info. There's also an edge case that file might be both |
| // loaded as a binary via `include_bytes!` and as proper `SourceFile` |
| // via `mod`, so we try to use real file contents and not just an |
| // empty string. |
| let text = std::str::from_utf8(&bytes).unwrap_or("").to_string(); |
| self.new_source_file(path.to_owned().into(), text); |
| Ok(bytes) |
| } |
| |
| // By returning a `MonotonicVec`, we ensure that consumers cannot invalidate |
| // any existing indices pointing into `files`. |
| pub fn files(&self) -> MappedReadGuard<'_, monotonic::MonotonicVec<Lrc<SourceFile>>> { |
| ReadGuard::map(self.files.borrow(), |files| &files.source_files) |
| } |
| |
| pub fn source_file_by_stable_id( |
| &self, |
| stable_id: StableSourceFileId, |
| ) -> Option<Lrc<SourceFile>> { |
| self.files.borrow().stable_id_to_source_file.get(&stable_id).cloned() |
| } |
| |
| fn allocate_address_space(&self, size: usize) -> Result<usize, OffsetOverflowError> { |
| let size = u32::try_from(size).map_err(|_| OffsetOverflowError)?; |
| |
| loop { |
| let current = self.used_address_space.load(Ordering::Relaxed); |
| let next = current |
| .checked_add(size) |
| // Add one so there is some space between files. This lets us distinguish |
| // positions in the `SourceMap`, even in the presence of zero-length files. |
| .and_then(|next| next.checked_add(1)) |
| .ok_or(OffsetOverflowError)?; |
| |
| if self |
| .used_address_space |
| .compare_exchange(current, next, Ordering::Relaxed, Ordering::Relaxed) |
| .is_ok() |
| { |
| return Ok(usize::try_from(current).unwrap()); |
| } |
| } |
| } |
| |
| /// Creates a new `SourceFile`. |
| /// If a file already exists in the `SourceMap` with the same ID, that file is returned |
| /// unmodified. |
| pub fn new_source_file(&self, filename: FileName, src: String) -> Lrc<SourceFile> { |
| self.try_new_source_file(filename, src).unwrap_or_else(|OffsetOverflowError| { |
| eprintln!("fatal error: rustc does not support files larger than 4GB"); |
| crate::fatal_error::FatalError.raise() |
| }) |
| } |
| |
| fn try_new_source_file( |
| &self, |
| filename: FileName, |
| src: String, |
| ) -> Result<Lrc<SourceFile>, OffsetOverflowError> { |
| // Note that filename may not be a valid path, eg it may be `<anon>` etc, |
| // but this is okay because the directory determined by `path.pop()` will |
| // be empty, so the working directory will be used. |
| let (filename, _) = self.path_mapping.map_filename_prefix(&filename); |
| |
| let file_id = StableSourceFileId::new_from_name(&filename, LOCAL_CRATE); |
| |
| let lrc_sf = match self.source_file_by_stable_id(file_id) { |
| Some(lrc_sf) => lrc_sf, |
| None => { |
| let start_pos = self.allocate_address_space(src.len())?; |
| |
| let source_file = Lrc::new(SourceFile::new( |
| filename, |
| src, |
| Pos::from_usize(start_pos), |
| self.hash_kind, |
| )); |
| |
| // Let's make sure the file_id we generated above actually matches |
| // the ID we generate for the SourceFile we just created. |
| debug_assert_eq!(StableSourceFileId::new(&source_file), file_id); |
| |
| let mut files = self.files.borrow_mut(); |
| |
| files.source_files.push(source_file.clone()); |
| files.stable_id_to_source_file.insert(file_id, source_file.clone()); |
| |
| source_file |
| } |
| }; |
| Ok(lrc_sf) |
| } |
| |
| /// Allocates a new `SourceFile` representing a source file from an external |
| /// crate. The source code of such an "imported `SourceFile`" is not available, |
| /// but we still know enough to generate accurate debuginfo location |
| /// information for things inlined from other crates. |
| pub fn new_imported_source_file( |
| &self, |
| filename: FileName, |
| src_hash: SourceFileHash, |
| name_hash: u128, |
| source_len: usize, |
| cnum: CrateNum, |
| mut file_local_lines: Vec<BytePos>, |
| mut file_local_multibyte_chars: Vec<MultiByteChar>, |
| mut file_local_non_narrow_chars: Vec<NonNarrowChar>, |
| mut file_local_normalized_pos: Vec<NormalizedPos>, |
| original_start_pos: BytePos, |
| original_end_pos: BytePos, |
| ) -> Lrc<SourceFile> { |
| let start_pos = self |
| .allocate_address_space(source_len) |
| .expect("not enough address space for imported source file"); |
| |
| let end_pos = Pos::from_usize(start_pos + source_len); |
| let start_pos = Pos::from_usize(start_pos); |
| |
| for pos in &mut file_local_lines { |
| *pos = *pos + start_pos; |
| } |
| |
| for mbc in &mut file_local_multibyte_chars { |
| mbc.pos = mbc.pos + start_pos; |
| } |
| |
| for swc in &mut file_local_non_narrow_chars { |
| *swc = *swc + start_pos; |
| } |
| |
| for nc in &mut file_local_normalized_pos { |
| nc.pos = nc.pos + start_pos; |
| } |
| |
| let source_file = Lrc::new(SourceFile { |
| name: filename, |
| src: None, |
| src_hash, |
| external_src: Lock::new(ExternalSource::Foreign { |
| kind: ExternalSourceKind::AbsentOk, |
| original_start_pos, |
| original_end_pos, |
| }), |
| start_pos, |
| end_pos, |
| lines: file_local_lines, |
| multibyte_chars: file_local_multibyte_chars, |
| non_narrow_chars: file_local_non_narrow_chars, |
| normalized_pos: file_local_normalized_pos, |
| name_hash, |
| cnum, |
| }); |
| |
| let mut files = self.files.borrow_mut(); |
| |
| files.source_files.push(source_file.clone()); |
| files |
| .stable_id_to_source_file |
| .insert(StableSourceFileId::new(&source_file), source_file.clone()); |
| |
| source_file |
| } |
| |
| // If there is a doctest offset, applies it to the line. |
| pub fn doctest_offset_line(&self, file: &FileName, orig: usize) -> usize { |
| match file { |
| FileName::DocTest(_, offset) => { |
| if *offset < 0 { |
| orig - (-(*offset)) as usize |
| } else { |
| orig + *offset as usize |
| } |
| } |
| _ => orig, |
| } |
| } |
| |
| /// Return the SourceFile that contains the given `BytePos` |
| pub fn lookup_source_file(&self, pos: BytePos) -> Lrc<SourceFile> { |
| let idx = self.lookup_source_file_idx(pos); |
| (*self.files.borrow().source_files)[idx].clone() |
| } |
| |
| /// Looks up source information about a `BytePos`. |
| pub fn lookup_char_pos(&self, pos: BytePos) -> Loc { |
| let sf = self.lookup_source_file(pos); |
| let (line, col, col_display) = sf.lookup_file_pos_with_col_display(pos); |
| Loc { file: sf, line, col, col_display } |
| } |
| |
| // If the corresponding `SourceFile` is empty, does not return a line number. |
| pub fn lookup_line(&self, pos: BytePos) -> Result<SourceFileAndLine, Lrc<SourceFile>> { |
| let f = self.lookup_source_file(pos); |
| |
| match f.lookup_line(pos) { |
| Some(line) => Ok(SourceFileAndLine { sf: f, line }), |
| None => Err(f), |
| } |
| } |
| |
| fn span_to_string(&self, sp: Span, filename_display_pref: FileNameDisplayPreference) -> String { |
| if self.files.borrow().source_files.is_empty() || sp.is_dummy() { |
| return "no-location".to_string(); |
| } |
| |
| let lo = self.lookup_char_pos(sp.lo()); |
| let hi = self.lookup_char_pos(sp.hi()); |
| format!( |
| "{}:{}:{}: {}:{}", |
| lo.file.name.display(filename_display_pref), |
| lo.line, |
| lo.col.to_usize() + 1, |
| hi.line, |
| hi.col.to_usize() + 1, |
| ) |
| } |
| |
| /// Format the span location suitable for embedding in build artifacts |
| pub fn span_to_embeddable_string(&self, sp: Span) -> String { |
| self.span_to_string(sp, FileNameDisplayPreference::Remapped) |
| } |
| |
| /// Format the span location to be printed in diagnostics. Must not be emitted |
| /// to build artifacts as this may leak local file paths. Use span_to_embeddable_string |
| /// for string suitable for embedding. |
| pub fn span_to_diagnostic_string(&self, sp: Span) -> String { |
| self.span_to_string(sp, self.path_mapping.filename_display_for_diagnostics) |
| } |
| |
| pub fn span_to_filename(&self, sp: Span) -> FileName { |
| self.lookup_char_pos(sp.lo()).file.name.clone() |
| } |
| |
| pub fn filename_for_diagnostics<'a>(&self, filename: &'a FileName) -> FileNameDisplay<'a> { |
| filename.display(self.path_mapping.filename_display_for_diagnostics) |
| } |
| |
| pub fn is_multiline(&self, sp: Span) -> bool { |
| let lo = self.lookup_source_file_idx(sp.lo()); |
| let hi = self.lookup_source_file_idx(sp.hi()); |
| if lo != hi { |
| return true; |
| } |
| let f = (*self.files.borrow().source_files)[lo].clone(); |
| f.lookup_line(sp.lo()) != f.lookup_line(sp.hi()) |
| } |
| |
| #[instrument(skip(self), level = "trace")] |
| pub fn is_valid_span(&self, sp: Span) -> Result<(Loc, Loc), SpanLinesError> { |
| let lo = self.lookup_char_pos(sp.lo()); |
| trace!(?lo); |
| let hi = self.lookup_char_pos(sp.hi()); |
| trace!(?hi); |
| if lo.file.start_pos != hi.file.start_pos { |
| return Err(SpanLinesError::DistinctSources(DistinctSources { |
| begin: (lo.file.name.clone(), lo.file.start_pos), |
| end: (hi.file.name.clone(), hi.file.start_pos), |
| })); |
| } |
| Ok((lo, hi)) |
| } |
| |
| pub fn is_line_before_span_empty(&self, sp: Span) -> bool { |
| match self.span_to_prev_source(sp) { |
| Ok(s) => s.rsplit_once('\n').unwrap_or(("", &s)).1.trim_start().is_empty(), |
| Err(_) => false, |
| } |
| } |
| |
| pub fn span_to_lines(&self, sp: Span) -> FileLinesResult { |
| debug!("span_to_lines(sp={:?})", sp); |
| let (lo, hi) = self.is_valid_span(sp)?; |
| assert!(hi.line >= lo.line); |
| |
| if sp.is_dummy() { |
| return Ok(FileLines { file: lo.file, lines: Vec::new() }); |
| } |
| |
| let mut lines = Vec::with_capacity(hi.line - lo.line + 1); |
| |
| // The span starts partway through the first line, |
| // but after that it starts from offset 0. |
| let mut start_col = lo.col; |
| |
| // For every line but the last, it extends from `start_col` |
| // and to the end of the line. Be careful because the line |
| // numbers in Loc are 1-based, so we subtract 1 to get 0-based |
| // lines. |
| // |
| // FIXME: now that we handle DUMMY_SP up above, we should consider |
| // asserting that the line numbers here are all indeed 1-based. |
| let hi_line = hi.line.saturating_sub(1); |
| for line_index in lo.line.saturating_sub(1)..hi_line { |
| let line_len = lo.file.get_line(line_index).map_or(0, |s| s.chars().count()); |
| lines.push(LineInfo { line_index, start_col, end_col: CharPos::from_usize(line_len) }); |
| start_col = CharPos::from_usize(0); |
| } |
| |
| // For the last line, it extends from `start_col` to `hi.col`: |
| lines.push(LineInfo { line_index: hi_line, start_col, end_col: hi.col }); |
| |
| Ok(FileLines { file: lo.file, lines }) |
| } |
| |
| /// Extracts the source surrounding the given `Span` using the `extract_source` function. The |
| /// extract function takes three arguments: a string slice containing the source, an index in |
| /// the slice for the beginning of the span and an index in the slice for the end of the span. |
| fn span_to_source<F, T>(&self, sp: Span, extract_source: F) -> Result<T, SpanSnippetError> |
| where |
| F: Fn(&str, usize, usize) -> Result<T, SpanSnippetError>, |
| { |
| let local_begin = self.lookup_byte_offset(sp.lo()); |
| let local_end = self.lookup_byte_offset(sp.hi()); |
| |
| if local_begin.sf.start_pos != local_end.sf.start_pos { |
| Err(SpanSnippetError::DistinctSources(DistinctSources { |
| begin: (local_begin.sf.name.clone(), local_begin.sf.start_pos), |
| end: (local_end.sf.name.clone(), local_end.sf.start_pos), |
| })) |
| } else { |
| self.ensure_source_file_source_present(local_begin.sf.clone()); |
| |
| let start_index = local_begin.pos.to_usize(); |
| let end_index = local_end.pos.to_usize(); |
| let source_len = (local_begin.sf.end_pos - local_begin.sf.start_pos).to_usize(); |
| |
| if start_index > end_index || end_index > source_len { |
| return Err(SpanSnippetError::MalformedForSourcemap(MalformedSourceMapPositions { |
| name: local_begin.sf.name.clone(), |
| source_len, |
| begin_pos: local_begin.pos, |
| end_pos: local_end.pos, |
| })); |
| } |
| |
| if let Some(ref src) = local_begin.sf.src { |
| extract_source(src, start_index, end_index) |
| } else if let Some(src) = local_begin.sf.external_src.borrow().get_source() { |
| extract_source(src, start_index, end_index) |
| } else { |
| Err(SpanSnippetError::SourceNotAvailable { filename: local_begin.sf.name.clone() }) |
| } |
| } |
| } |
| |
| /// Returns whether or not this span points into a file |
| /// in the current crate. This may be `false` for spans |
| /// produced by a macro expansion, or for spans associated |
| /// with the definition of an item in a foreign crate |
| pub fn is_local_span(&self, sp: Span) -> bool { |
| let local_begin = self.lookup_byte_offset(sp.lo()); |
| let local_end = self.lookup_byte_offset(sp.hi()); |
| // This might be a weird span that covers multiple files |
| local_begin.sf.src.is_some() && local_end.sf.src.is_some() |
| } |
| |
| /// Returns the source snippet as `String` corresponding to the given `Span`. |
| pub fn span_to_snippet(&self, sp: Span) -> Result<String, SpanSnippetError> { |
| self.span_to_source(sp, |src, start_index, end_index| { |
| src.get(start_index..end_index) |
| .map(|s| s.to_string()) |
| .ok_or(SpanSnippetError::IllFormedSpan(sp)) |
| }) |
| } |
| |
| pub fn span_to_margin(&self, sp: Span) -> Option<usize> { |
| Some(self.indentation_before(sp)?.len()) |
| } |
| |
| pub fn indentation_before(&self, sp: Span) -> Option<String> { |
| self.span_to_source(sp, |src, start_index, _| { |
| let before = &src[..start_index]; |
| let last_line = before.rsplit_once('\n').map_or(before, |(_, last)| last); |
| Ok(last_line |
| .split_once(|c: char| !c.is_whitespace()) |
| .map_or(last_line, |(indent, _)| indent) |
| .to_string()) |
| }) |
| .ok() |
| } |
| |
| /// Returns the source snippet as `String` before the given `Span`. |
| pub fn span_to_prev_source(&self, sp: Span) -> Result<String, SpanSnippetError> { |
| self.span_to_source(sp, |src, start_index, _| { |
| src.get(..start_index).map(|s| s.to_string()).ok_or(SpanSnippetError::IllFormedSpan(sp)) |
| }) |
| } |
| |
| /// Extends the given `Span` to just after the previous occurrence of `c`. Return the same span |
| /// if no character could be found or if an error occurred while retrieving the code snippet. |
| pub fn span_extend_to_prev_char(&self, sp: Span, c: char, accept_newlines: bool) -> Span { |
| if let Ok(prev_source) = self.span_to_prev_source(sp) { |
| let prev_source = prev_source.rsplit(c).next().unwrap_or(""); |
| if !prev_source.is_empty() && (accept_newlines || !prev_source.contains('\n')) { |
| return sp.with_lo(BytePos(sp.lo().0 - prev_source.len() as u32)); |
| } |
| } |
| |
| sp |
| } |
| |
| /// Extends the given `Span` to just after the previous occurrence of `pat` when surrounded by |
| /// whitespace. Returns None if the pattern could not be found or if an error occurred while |
| /// retrieving the code snippet. |
| pub fn span_extend_to_prev_str( |
| &self, |
| sp: Span, |
| pat: &str, |
| accept_newlines: bool, |
| include_whitespace: bool, |
| ) -> Option<Span> { |
| // assure that the pattern is delimited, to avoid the following |
| // fn my_fn() |
| // ^^^^ returned span without the check |
| // ---------- correct span |
| let prev_source = self.span_to_prev_source(sp).ok()?; |
| for ws in &[" ", "\t", "\n"] { |
| let pat = pat.to_owned() + ws; |
| if let Some(pat_pos) = prev_source.rfind(&pat) { |
| let just_after_pat_pos = pat_pos + pat.len() - 1; |
| let just_after_pat_plus_ws = if include_whitespace { |
| just_after_pat_pos |
| + prev_source[just_after_pat_pos..] |
| .find(|c: char| !c.is_whitespace()) |
| .unwrap_or(0) |
| } else { |
| just_after_pat_pos |
| }; |
| let len = prev_source.len() - just_after_pat_plus_ws; |
| let prev_source = &prev_source[just_after_pat_plus_ws..]; |
| if accept_newlines || !prev_source.trim_start().contains('\n') { |
| return Some(sp.with_lo(BytePos(sp.lo().0 - len as u32))); |
| } |
| } |
| } |
| |
| None |
| } |
| |
| /// Returns the source snippet as `String` after the given `Span`. |
| pub fn span_to_next_source(&self, sp: Span) -> Result<String, SpanSnippetError> { |
| self.span_to_source(sp, |src, _, end_index| { |
| src.get(end_index..).map(|s| s.to_string()).ok_or(SpanSnippetError::IllFormedSpan(sp)) |
| }) |
| } |
| |
| /// Extends the given `Span` while the next character matches the predicate |
| pub fn span_extend_while( |
| &self, |
| span: Span, |
| f: impl Fn(char) -> bool, |
| ) -> Result<Span, SpanSnippetError> { |
| self.span_to_source(span, |s, _start, end| { |
| let n = s[end..].char_indices().find(|&(_, c)| !f(c)).map_or(s.len() - end, |(i, _)| i); |
| Ok(span.with_hi(span.hi() + BytePos(n as u32))) |
| }) |
| } |
| |
| /// Extends the given `Span` to just after the next occurrence of `c`. |
| pub fn span_extend_to_next_char(&self, sp: Span, c: char, accept_newlines: bool) -> Span { |
| if let Ok(next_source) = self.span_to_next_source(sp) { |
| let next_source = next_source.split(c).next().unwrap_or(""); |
| if !next_source.is_empty() && (accept_newlines || !next_source.contains('\n')) { |
| return sp.with_hi(BytePos(sp.hi().0 + next_source.len() as u32)); |
| } |
| } |
| |
| sp |
| } |
| |
| /// Given a `Span`, tries to get a shorter span ending before the first occurrence of `char` |
| /// `c`. |
| pub fn span_until_char(&self, sp: Span, c: char) -> Span { |
| match self.span_to_snippet(sp) { |
| Ok(snippet) => { |
| let snippet = snippet.split(c).next().unwrap_or("").trim_end(); |
| if !snippet.is_empty() && !snippet.contains('\n') { |
| sp.with_hi(BytePos(sp.lo().0 + snippet.len() as u32)) |
| } else { |
| sp |
| } |
| } |
| _ => sp, |
| } |
| } |
| |
| /// Given a `Span`, tries to get a shorter span ending just after the first occurrence of `char` |
| /// `c`. |
| pub fn span_through_char(&self, sp: Span, c: char) -> Span { |
| if let Ok(snippet) = self.span_to_snippet(sp) { |
| if let Some(offset) = snippet.find(c) { |
| return sp.with_hi(BytePos(sp.lo().0 + (offset + c.len_utf8()) as u32)); |
| } |
| } |
| sp |
| } |
| |
| /// Given a `Span`, gets a new `Span` covering the first token and all its trailing whitespace |
| /// or the original `Span`. |
| /// |
| /// If `sp` points to `"let mut x"`, then a span pointing at `"let "` will be returned. |
| pub fn span_until_non_whitespace(&self, sp: Span) -> Span { |
| let mut whitespace_found = false; |
| |
| self.span_take_while(sp, |c| { |
| if !whitespace_found && c.is_whitespace() { |
| whitespace_found = true; |
| } |
| |
| !whitespace_found || c.is_whitespace() |
| }) |
| } |
| |
| /// Given a `Span`, gets a new `Span` covering the first token without its trailing whitespace |
| /// or the original `Span` in case of error. |
| /// |
| /// If `sp` points to `"let mut x"`, then a span pointing at `"let"` will be returned. |
| pub fn span_until_whitespace(&self, sp: Span) -> Span { |
| self.span_take_while(sp, |c| !c.is_whitespace()) |
| } |
| |
| /// Given a `Span`, gets a shorter one until `predicate` yields `false`. |
| pub fn span_take_while<P>(&self, sp: Span, predicate: P) -> Span |
| where |
| P: for<'r> FnMut(&'r char) -> bool, |
| { |
| if let Ok(snippet) = self.span_to_snippet(sp) { |
| let offset = snippet.chars().take_while(predicate).map(|c| c.len_utf8()).sum::<usize>(); |
| |
| sp.with_hi(BytePos(sp.lo().0 + (offset as u32))) |
| } else { |
| sp |
| } |
| } |
| |
| /// Given a `Span`, return a span ending in the closest `{`. This is useful when you have a |
| /// `Span` enclosing a whole item but we need to point at only the head (usually the first |
| /// line) of that item. |
| /// |
| /// *Only suitable for diagnostics.* |
| pub fn guess_head_span(&self, sp: Span) -> Span { |
| // FIXME: extend the AST items to have a head span, or replace callers with pointing at |
| // the item's ident when appropriate. |
| self.span_until_char(sp, '{') |
| } |
| |
| /// Returns a new span representing just the first character of the given span. |
| pub fn start_point(&self, sp: Span) -> Span { |
| let width = { |
| let sp = sp.data(); |
| let local_begin = self.lookup_byte_offset(sp.lo); |
| let start_index = local_begin.pos.to_usize(); |
| let src = local_begin.sf.external_src.borrow(); |
| |
| let snippet = if let Some(ref src) = local_begin.sf.src { |
| Some(&src[start_index..]) |
| } else if let Some(src) = src.get_source() { |
| Some(&src[start_index..]) |
| } else { |
| None |
| }; |
| |
| match snippet { |
| None => 1, |
| Some(snippet) => match snippet.chars().next() { |
| None => 1, |
| Some(c) => c.len_utf8(), |
| }, |
| } |
| }; |
| |
| sp.with_hi(BytePos(sp.lo().0 + width as u32)) |
| } |
| |
| /// Returns a new span representing just the last character of this span. |
| pub fn end_point(&self, sp: Span) -> Span { |
| let pos = sp.hi().0; |
| |
| let width = self.find_width_of_character_at_span(sp, false); |
| let corrected_end_position = pos.checked_sub(width).unwrap_or(pos); |
| |
| let end_point = BytePos(cmp::max(corrected_end_position, sp.lo().0)); |
| sp.with_lo(end_point) |
| } |
| |
| /// Returns a new span representing the next character after the end-point of this span. |
| pub fn next_point(&self, sp: Span) -> Span { |
| if sp.is_dummy() { |
| return sp; |
| } |
| let start_of_next_point = sp.hi().0; |
| |
| let width = self.find_width_of_character_at_span(sp.shrink_to_hi(), true); |
| // If the width is 1, then the next span should point to the same `lo` and `hi`. However, |
| // in the case of a multibyte character, where the width != 1, the next span should |
| // span multiple bytes to include the whole character. |
| let end_of_next_point = |
| start_of_next_point.checked_add(width - 1).unwrap_or(start_of_next_point); |
| |
| let end_of_next_point = BytePos(cmp::max(sp.lo().0 + 1, end_of_next_point)); |
| Span::new(BytePos(start_of_next_point), end_of_next_point, sp.ctxt(), None) |
| } |
| |
| /// Finds the width of the character, either before or after the end of provided span, |
| /// depending on the `forwards` parameter. |
| fn find_width_of_character_at_span(&self, sp: Span, forwards: bool) -> u32 { |
| let sp = sp.data(); |
| if sp.lo == sp.hi { |
| debug!("find_width_of_character_at_span: early return empty span"); |
| return 1; |
| } |
| |
| let local_begin = self.lookup_byte_offset(sp.lo); |
| let local_end = self.lookup_byte_offset(sp.hi); |
| debug!( |
| "find_width_of_character_at_span: local_begin=`{:?}`, local_end=`{:?}`", |
| local_begin, local_end |
| ); |
| |
| if local_begin.sf.start_pos != local_end.sf.start_pos { |
| debug!("find_width_of_character_at_span: begin and end are in different files"); |
| return 1; |
| } |
| |
| let start_index = local_begin.pos.to_usize(); |
| let end_index = local_end.pos.to_usize(); |
| debug!( |
| "find_width_of_character_at_span: start_index=`{:?}`, end_index=`{:?}`", |
| start_index, end_index |
| ); |
| |
| // Disregard indexes that are at the start or end of their spans, they can't fit bigger |
| // characters. |
| if (!forwards && end_index == usize::MIN) || (forwards && start_index == usize::MAX) { |
| debug!("find_width_of_character_at_span: start or end of span, cannot be multibyte"); |
| return 1; |
| } |
| |
| let source_len = (local_begin.sf.end_pos - local_begin.sf.start_pos).to_usize(); |
| debug!("find_width_of_character_at_span: source_len=`{:?}`", source_len); |
| // Ensure indexes are also not malformed. |
| if start_index > end_index || end_index > source_len { |
| debug!("find_width_of_character_at_span: source indexes are malformed"); |
| return 1; |
| } |
| |
| let src = local_begin.sf.external_src.borrow(); |
| |
| // We need to extend the snippet to the end of the src rather than to end_index so when |
| // searching forwards for boundaries we've got somewhere to search. |
| let snippet = if let Some(ref src) = local_begin.sf.src { |
| &src[start_index..] |
| } else if let Some(src) = src.get_source() { |
| &src[start_index..] |
| } else { |
| return 1; |
| }; |
| debug!("find_width_of_character_at_span: snippet=`{:?}`", snippet); |
| |
| let mut target = if forwards { end_index + 1 } else { end_index - 1 }; |
| debug!("find_width_of_character_at_span: initial target=`{:?}`", target); |
| |
| while !snippet.is_char_boundary(target - start_index) && target < source_len { |
| target = if forwards { |
| target + 1 |
| } else { |
| match target.checked_sub(1) { |
| Some(target) => target, |
| None => { |
| break; |
| } |
| } |
| }; |
| debug!("find_width_of_character_at_span: target=`{:?}`", target); |
| } |
| debug!("find_width_of_character_at_span: final target=`{:?}`", target); |
| |
| if forwards { (target - end_index) as u32 } else { (end_index - target) as u32 } |
| } |
| |
| pub fn get_source_file(&self, filename: &FileName) -> Option<Lrc<SourceFile>> { |
| // Remap filename before lookup |
| let filename = self.path_mapping().map_filename_prefix(filename).0; |
| for sf in self.files.borrow().source_files.iter() { |
| if filename == sf.name { |
| return Some(sf.clone()); |
| } |
| } |
| None |
| } |
| |
| /// For a global `BytePos`, computes the local offset within the containing `SourceFile`. |
| pub fn lookup_byte_offset(&self, bpos: BytePos) -> SourceFileAndBytePos { |
| let idx = self.lookup_source_file_idx(bpos); |
| let sf = (*self.files.borrow().source_files)[idx].clone(); |
| let offset = bpos - sf.start_pos; |
| SourceFileAndBytePos { sf, pos: offset } |
| } |
| |
| // Returns the index of the `SourceFile` (in `self.files`) that contains `pos`. |
| // This index is guaranteed to be valid for the lifetime of this `SourceMap`, |
| // since `source_files` is a `MonotonicVec` |
| pub fn lookup_source_file_idx(&self, pos: BytePos) -> usize { |
| self.files |
| .borrow() |
| .source_files |
| .binary_search_by_key(&pos, |key| key.start_pos) |
| .unwrap_or_else(|p| p - 1) |
| } |
| |
| pub fn count_lines(&self) -> usize { |
| self.files().iter().fold(0, |a, f| a + f.count_lines()) |
| } |
| |
| pub fn generate_fn_name_span(&self, span: Span) -> Option<Span> { |
| let prev_span = self.span_extend_to_prev_str(span, "fn", true, true).unwrap_or(span); |
| if let Ok(snippet) = self.span_to_snippet(prev_span) { |
| debug!( |
| "generate_fn_name_span: span={:?}, prev_span={:?}, snippet={:?}", |
| span, prev_span, snippet |
| ); |
| |
| if snippet.is_empty() { |
| return None; |
| }; |
| |
| let len = snippet |
| .find(|c: char| !c.is_alphanumeric() && c != '_') |
| .expect("no label after fn"); |
| Some(prev_span.with_hi(BytePos(prev_span.lo().0 + len as u32))) |
| } else { |
| None |
| } |
| } |
| |
| /// Takes the span of a type parameter in a function signature and try to generate a span for |
| /// the function name (with generics) and a new snippet for this span with the pointed type |
| /// parameter as a new local type parameter. |
| /// |
| /// For instance: |
| /// ```rust,ignore (pseudo-Rust) |
| /// // Given span |
| /// fn my_function(param: T) |
| /// // ^ Original span |
| /// |
| /// // Result |
| /// fn my_function(param: T) |
| /// // ^^^^^^^^^^^ Generated span with snippet `my_function<T>` |
| /// ``` |
| /// |
| /// Attention: The method used is very fragile since it essentially duplicates the work of the |
| /// parser. If you need to use this function or something similar, please consider updating the |
| /// `SourceMap` functions and this function to something more robust. |
| pub fn generate_local_type_param_snippet(&self, span: Span) -> Option<(Span, String)> { |
| // Try to extend the span to the previous "fn" keyword to retrieve the function |
| // signature. |
| if let Some(sugg_span) = self.span_extend_to_prev_str(span, "fn", false, true) { |
| if let Ok(snippet) = self.span_to_snippet(sugg_span) { |
| // Consume the function name. |
| let mut offset = snippet |
| .find(|c: char| !c.is_alphanumeric() && c != '_') |
| .expect("no label after fn"); |
| |
| // Consume the generics part of the function signature. |
| let mut bracket_counter = 0; |
| let mut last_char = None; |
| for c in snippet[offset..].chars() { |
| match c { |
| '<' => bracket_counter += 1, |
| '>' => bracket_counter -= 1, |
| '(' => { |
| if bracket_counter == 0 { |
| break; |
| } |
| } |
| _ => {} |
| } |
| offset += c.len_utf8(); |
| last_char = Some(c); |
| } |
| |
| // Adjust the suggestion span to encompass the function name with its generics. |
| let sugg_span = sugg_span.with_hi(BytePos(sugg_span.lo().0 + offset as u32)); |
| |
| // Prepare the new suggested snippet to append the type parameter that triggered |
| // the error in the generics of the function signature. |
| let mut new_snippet = if last_char == Some('>') { |
| format!("{}, ", &snippet[..(offset - '>'.len_utf8())]) |
| } else { |
| format!("{}<", &snippet[..offset]) |
| }; |
| new_snippet |
| .push_str(&self.span_to_snippet(span).unwrap_or_else(|_| "T".to_string())); |
| new_snippet.push('>'); |
| |
| return Some((sugg_span, new_snippet)); |
| } |
| } |
| |
| None |
| } |
| pub fn ensure_source_file_source_present(&self, source_file: Lrc<SourceFile>) -> bool { |
| source_file.add_external_src(|| { |
| match source_file.name { |
| FileName::Real(ref name) if let Some(local_path) = name.local_path() => { |
| self.file_loader.read_file(local_path).ok() |
| } |
| _ => None, |
| } |
| }) |
| } |
| |
| pub fn is_imported(&self, sp: Span) -> bool { |
| let source_file_index = self.lookup_source_file_idx(sp.lo()); |
| let source_file = &self.files()[source_file_index]; |
| source_file.is_imported() |
| } |
| |
| /// Gets the span of a statement. If the statement is a macro expansion, the |
| /// span in the context of the block span is found. The trailing semicolon is included |
| /// on a best-effort basis. |
| pub fn stmt_span(&self, stmt_span: Span, block_span: Span) -> Span { |
| if !stmt_span.from_expansion() { |
| return stmt_span; |
| } |
| let mac_call = original_sp(stmt_span, block_span); |
| self.mac_call_stmt_semi_span(mac_call).map_or(mac_call, |s| mac_call.with_hi(s.hi())) |
| } |
| |
| /// Tries to find the span of the semicolon of a macro call statement. |
| /// The input must be the *call site* span of a statement from macro expansion. |
| /// ```ignore (illustrative) |
| /// // v output |
| /// mac!(); |
| /// // ^^^^^^ input |
| /// ``` |
| pub fn mac_call_stmt_semi_span(&self, mac_call: Span) -> Option<Span> { |
| let span = self.span_extend_while(mac_call, char::is_whitespace).ok()?; |
| let span = span.shrink_to_hi().with_hi(BytePos(span.hi().0.checked_add(1)?)); |
| if self.span_to_snippet(span).as_deref() != Ok(";") { |
| return None; |
| } |
| Some(span) |
| } |
| } |
| |
| #[derive(Clone)] |
| pub struct FilePathMapping { |
| mapping: Vec<(PathBuf, PathBuf)>, |
| filename_display_for_diagnostics: FileNameDisplayPreference, |
| } |
| |
| impl FilePathMapping { |
| pub fn empty() -> FilePathMapping { |
| FilePathMapping::new(Vec::new()) |
| } |
| |
| pub fn new(mapping: Vec<(PathBuf, PathBuf)>) -> FilePathMapping { |
| let filename_display_for_diagnostics = if mapping.is_empty() { |
| FileNameDisplayPreference::Local |
| } else { |
| FileNameDisplayPreference::Remapped |
| }; |
| |
| FilePathMapping { mapping, filename_display_for_diagnostics } |
| } |
| |
| /// Applies any path prefix substitution as defined by the mapping. |
| /// The return value is the remapped path and a boolean indicating whether |
| /// the path was affected by the mapping. |
| pub fn map_prefix(&self, path: PathBuf) -> (PathBuf, bool) { |
| // NOTE: We are iterating over the mapping entries from last to first |
| // because entries specified later on the command line should |
| // take precedence. |
| for &(ref from, ref to) in self.mapping.iter().rev() { |
| if let Ok(rest) = path.strip_prefix(from) { |
| let remapped = if rest.as_os_str().is_empty() { |
| // This is subtle, joining an empty path onto e.g. `foo/bar` will |
| // result in `foo/bar/`, that is, there'll be an additional directory |
| // separator at the end. This can lead to duplicated directory separators |
| // in remapped paths down the line. |
| // So, if we have an exact match, we just return that without a call |
| // to `Path::join()`. |
| to.clone() |
| } else { |
| to.join(rest) |
| }; |
| |
| return (remapped, true); |
| } |
| } |
| |
| (path, false) |
| } |
| |
| fn map_filename_prefix(&self, file: &FileName) -> (FileName, bool) { |
| match file { |
| FileName::Real(realfile) if let RealFileName::LocalPath(local_path) = realfile => { |
| let (mapped_path, mapped) = self.map_prefix(local_path.to_path_buf()); |
| let realfile = if mapped { |
| RealFileName::Remapped { |
| local_path: Some(local_path.clone()), |
| virtual_name: mapped_path, |
| } |
| } else { |
| realfile.clone() |
| }; |
| (FileName::Real(realfile), mapped) |
| } |
| FileName::Real(_) => unreachable!("attempted to remap an already remapped filename"), |
| other => (other.clone(), false), |
| } |
| } |
| } |
