//! The source positions and related helper functions. //! //! ## Note //! //! This API is completely unstable and subject to change. #![doc(html_root_url = "https://doc.rust-lang.org/nightly/")] #![feature(rustc_private, const_fn)] #![feature(crate_visibility_modifier)] #![feature(nll)] #![feature(non_exhaustive)] #![feature(optin_builtin_traits)] #![feature(rustc_attrs)] #![feature(proc_macro_hygiene)] #![feature(specialization)] #![feature(step_trait)] use rustc_serialize::{Encodable, Decodable, Encoder, Decoder}; pub mod edition; use edition::Edition; pub mod hygiene; pub use hygiene::{ExpnId, SyntaxContext, ExpnData, ExpnKind, MacroKind, DesugaringKind}; use hygiene::Transparency; mod span_encoding; pub use span_encoding::{Span, DUMMY_SP}; pub mod symbol; pub use symbol::{Symbol, sym}; mod analyze_source_file; use rustc_data_structures::stable_hasher::StableHasher; use rustc_data_structures::sync::{Lrc, Lock}; use std::borrow::Cow; use std::cell::Cell; use std::cmp::{self, Ordering}; use std::fmt; use std::hash::{Hasher, Hash}; use std::ops::{Add, Sub}; use std::path::PathBuf; #[cfg(test)] mod tests; pub struct Globals { symbol_interner: Lock, span_interner: Lock, hygiene_data: Lock, } impl Globals { pub fn new(edition: Edition) -> Globals { Globals { symbol_interner: Lock::new(symbol::Interner::fresh()), span_interner: Lock::new(span_encoding::SpanInterner::default()), hygiene_data: Lock::new(hygiene::HygieneData::new(edition)), } } } scoped_tls::scoped_thread_local!(pub static GLOBALS: Globals); /// Differentiates between real files and common virtual files. #[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd, Hash, RustcDecodable, RustcEncodable)] pub enum FileName { Real(PathBuf), /// A macro. This includes the full name of the macro, so that there are no clashes. Macros(String), /// Call to `quote!`. QuoteExpansion(u64), /// Command line. Anon(u64), /// Hack in `src/libsyntax/parse.rs`. // FIXME(jseyfried) MacroExpansion(u64), ProcMacroSourceCode(u64), /// Strings provided as `--cfg [cfgspec]` stored in a `crate_cfg`. CfgSpec(u64), /// Strings provided as crate attributes in the CLI. CliCrateAttr(u64), /// Custom sources for explicit parser calls from plugins and drivers. Custom(String), DocTest(PathBuf, isize), } impl std::fmt::Display for FileName { fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { use FileName::*; match *self { Real(ref path) => write!(fmt, "{}", path.display()), Macros(ref name) => write!(fmt, "<{} macros>", name), QuoteExpansion(_) => write!(fmt, ""), MacroExpansion(_) => write!(fmt, ""), Anon(_) => write!(fmt, ""), ProcMacroSourceCode(_) => write!(fmt, ""), CfgSpec(_) => write!(fmt, ""), CliCrateAttr(_) => write!(fmt, ""), Custom(ref s) => write!(fmt, "<{}>", s), DocTest(ref path, _) => write!(fmt, "{}", path.display()), } } } impl From for FileName { fn from(p: PathBuf) -> Self { assert!(!p.to_string_lossy().ends_with('>')); FileName::Real(p) } } impl FileName { pub fn is_real(&self) -> bool { use FileName::*; match *self { Real(_) => true, Macros(_) | Anon(_) | MacroExpansion(_) | ProcMacroSourceCode(_) | CfgSpec(_) | CliCrateAttr(_) | Custom(_) | QuoteExpansion(_) | DocTest(_, _) => false, } } pub fn is_macros(&self) -> bool { use FileName::*; match *self { Real(_) | Anon(_) | MacroExpansion(_) | ProcMacroSourceCode(_) | CfgSpec(_) | CliCrateAttr(_) | Custom(_) | QuoteExpansion(_) | DocTest(_, _) => false, Macros(_) => true, } } pub fn quote_expansion_source_code(src: &str) -> FileName { let mut hasher = StableHasher::new(); src.hash(&mut hasher); FileName::QuoteExpansion(hasher.finish()) } pub fn macro_expansion_source_code(src: &str) -> FileName { let mut hasher = StableHasher::new(); src.hash(&mut hasher); FileName::MacroExpansion(hasher.finish()) } pub fn anon_source_code(src: &str) -> FileName { let mut hasher = StableHasher::new(); src.hash(&mut hasher); FileName::Anon(hasher.finish()) } pub fn proc_macro_source_code(src: &str) -> FileName { let mut hasher = StableHasher::new(); src.hash(&mut hasher); FileName::ProcMacroSourceCode(hasher.finish()) } pub fn cfg_spec_source_code(src: &str) -> FileName { let mut hasher = StableHasher::new(); src.hash(&mut hasher); FileName::QuoteExpansion(hasher.finish()) } pub fn cli_crate_attr_source_code(src: &str) -> FileName { let mut hasher = StableHasher::new(); src.hash(&mut hasher); FileName::CliCrateAttr(hasher.finish()) } pub fn doc_test_source_code(path: PathBuf, line: isize) -> FileName{ FileName::DocTest(path, line) } } /// Spans represent a region of code, used for error reporting. Positions in spans /// are *absolute* positions from the beginning of the source_map, not positions /// relative to `SourceFile`s. Methods on the `SourceMap` can be used to relate spans back /// to the original source. /// You must be careful if the span crosses more than one file - you will not be /// able to use many of the functions on spans in source_map and you cannot assume /// that the length of the `span = hi - lo`; there may be space in the `BytePos` /// range between files. /// /// `SpanData` is public because `Span` uses a thread-local interner and can't be /// sent to other threads, but some pieces of performance infra run in a separate thread. /// Using `Span` is generally preferred. #[derive(Clone, Copy, Hash, PartialEq, Eq, Ord, PartialOrd)] pub struct SpanData { pub lo: BytePos, pub hi: BytePos, /// Information about where the macro came from, if this piece of /// code was created by a macro expansion. pub ctxt: SyntaxContext, } impl SpanData { #[inline] pub fn with_lo(&self, lo: BytePos) -> Span { Span::new(lo, self.hi, self.ctxt) } #[inline] pub fn with_hi(&self, hi: BytePos) -> Span { Span::new(self.lo, hi, self.ctxt) } #[inline] pub fn with_ctxt(&self, ctxt: SyntaxContext) -> Span { Span::new(self.lo, self.hi, ctxt) } } // The interner is pointed to by a thread local value which is only set on the main thread // with parallelization is disabled. So we don't allow `Span` to transfer between threads // to avoid panics and other errors, even though it would be memory safe to do so. #[cfg(not(parallel_compiler))] impl !Send for Span {} #[cfg(not(parallel_compiler))] impl !Sync for Span {} impl PartialOrd for Span { fn partial_cmp(&self, rhs: &Self) -> Option { PartialOrd::partial_cmp(&self.data(), &rhs.data()) } } impl Ord for Span { fn cmp(&self, rhs: &Self) -> Ordering { Ord::cmp(&self.data(), &rhs.data()) } } /// A collection of spans. Spans have two orthogonal attributes: /// /// - They can be *primary spans*. In this case they are the locus of /// the error, and would be rendered with `^^^`. /// - They can have a *label*. In this case, the label is written next /// to the mark in the snippet when we render. #[derive(Clone, Debug, Hash, PartialEq, Eq, RustcEncodable, RustcDecodable)] pub struct MultiSpan { primary_spans: Vec, span_labels: Vec<(Span, String)>, } impl Span { #[inline] pub fn lo(self) -> BytePos { self.data().lo } #[inline] pub fn with_lo(self, lo: BytePos) -> Span { self.data().with_lo(lo) } #[inline] pub fn hi(self) -> BytePos { self.data().hi } #[inline] pub fn with_hi(self, hi: BytePos) -> Span { self.data().with_hi(hi) } #[inline] pub fn ctxt(self) -> SyntaxContext { self.data().ctxt } #[inline] pub fn with_ctxt(self, ctxt: SyntaxContext) -> Span { self.data().with_ctxt(ctxt) } /// Returns `true` if this is a dummy span with any hygienic context. #[inline] pub fn is_dummy(self) -> bool { let span = self.data(); span.lo.0 == 0 && span.hi.0 == 0 } /// Returns `true` if this span comes from a macro or desugaring. #[inline] pub fn from_expansion(self) -> bool { self.ctxt() != SyntaxContext::root() } #[inline] pub fn with_root_ctxt(lo: BytePos, hi: BytePos) -> Span { Span::new(lo, hi, SyntaxContext::root()) } /// Returns a new span representing an empty span at the beginning of this span #[inline] pub fn shrink_to_lo(self) -> Span { let span = self.data(); span.with_hi(span.lo) } /// Returns a new span representing an empty span at the end of this span. #[inline] pub fn shrink_to_hi(self) -> Span { let span = self.data(); span.with_lo(span.hi) } /// Returns `self` if `self` is not the dummy span, and `other` otherwise. pub fn substitute_dummy(self, other: Span) -> Span { if self.is_dummy() { other } else { self } } /// Returns `true` if `self` fully encloses `other`. pub fn contains(self, other: Span) -> bool { let span = self.data(); let other = other.data(); span.lo <= other.lo && other.hi <= span.hi } /// Returns `true` if `self` touches `other`. pub fn overlaps(self, other: Span) -> bool { let span = self.data(); let other = other.data(); span.lo < other.hi && other.lo < span.hi } /// Returns `true` if the spans are equal with regards to the source text. /// /// Use this instead of `==` when either span could be generated code, /// and you only care that they point to the same bytes of source text. pub fn source_equal(&self, other: &Span) -> bool { let span = self.data(); let other = other.data(); span.lo == other.lo && span.hi == other.hi } /// Returns `Some(span)`, where the start is trimmed by the end of `other`. pub fn trim_start(self, other: Span) -> Option { let span = self.data(); let other = other.data(); if span.hi > other.hi { Some(span.with_lo(cmp::max(span.lo, other.hi))) } else { None } } /// Returns the source span -- this is either the supplied span, or the span for /// the macro callsite that expanded to it. pub fn source_callsite(self) -> Span { let expn_data = self.ctxt().outer_expn_data(); if !expn_data.is_root() { expn_data.call_site.source_callsite() } else { self } } /// The `Span` for the tokens in the previous macro expansion from which `self` was generated, /// if any. pub fn parent(self) -> Option { let expn_data = self.ctxt().outer_expn_data(); if !expn_data.is_root() { Some(expn_data.call_site) } else { None } } /// Edition of the crate from which this span came. pub fn edition(self) -> edition::Edition { self.ctxt().outer_expn_data().edition } #[inline] pub fn rust_2015(&self) -> bool { self.edition() == edition::Edition::Edition2015 } #[inline] pub fn rust_2018(&self) -> bool { self.edition() >= edition::Edition::Edition2018 } /// Returns the source callee. /// /// Returns `None` if the supplied span has no expansion trace, /// else returns the `ExpnData` for the macro definition /// corresponding to the source callsite. pub fn source_callee(self) -> Option { fn source_callee(expn_data: ExpnData) -> ExpnData { let next_expn_data = expn_data.call_site.ctxt().outer_expn_data(); if !next_expn_data.is_root() { source_callee(next_expn_data) } else { expn_data } } let expn_data = self.ctxt().outer_expn_data(); if !expn_data.is_root() { Some(source_callee(expn_data)) } else { None } } /// Checks if a span is "internal" to a macro in which `#[unstable]` /// items can be used (that is, a macro marked with /// `#[allow_internal_unstable]`). pub fn allows_unstable(&self, feature: Symbol) -> bool { self.ctxt().outer_expn_data().allow_internal_unstable.map_or(false, |features| { features.iter().any(|&f| { f == feature || f == sym::allow_internal_unstable_backcompat_hack }) }) } /// Checks if this span arises from a compiler desugaring of kind `kind`. pub fn is_desugaring(&self, kind: DesugaringKind) -> bool { match self.ctxt().outer_expn_data().kind { ExpnKind::Desugaring(k) => k == kind, _ => false, } } /// Returns the compiler desugaring that created this span, or `None` /// if this span is not from a desugaring. pub fn desugaring_kind(&self) -> Option { match self.ctxt().outer_expn_data().kind { ExpnKind::Desugaring(k) => Some(k), _ => None } } /// Checks if a span is "internal" to a macro in which `unsafe` /// can be used without triggering the `unsafe_code` lint // (that is, a macro marked with `#[allow_internal_unsafe]`). pub fn allows_unsafe(&self) -> bool { self.ctxt().outer_expn_data().allow_internal_unsafe } pub fn macro_backtrace(mut self) -> Vec { let mut prev_span = DUMMY_SP; let mut result = vec![]; loop { let expn_data = self.ctxt().outer_expn_data(); if expn_data.is_root() { break; } // Don't print recursive invocations. if !expn_data.call_site.source_equal(&prev_span) { let (pre, post) = match expn_data.kind { ExpnKind::Root => break, ExpnKind::Desugaring(..) => ("desugaring of ", ""), ExpnKind::AstPass(..) => ("", ""), ExpnKind::Macro(macro_kind, _) => match macro_kind { MacroKind::Bang => ("", "!"), MacroKind::Attr => ("#[", "]"), MacroKind::Derive => ("#[derive(", ")]"), } }; result.push(MacroBacktrace { call_site: expn_data.call_site, macro_decl_name: format!("{}{}{}", pre, expn_data.kind.descr(), post), def_site_span: expn_data.def_site, }); } prev_span = self; self = expn_data.call_site; } result } /// Returns a `Span` that would enclose both `self` and `end`. pub fn to(self, end: Span) -> Span { let span_data = self.data(); let end_data = end.data(); // FIXME(jseyfried): `self.ctxt` should always equal `end.ctxt` here (cf. issue #23480). // Return the macro span on its own to avoid weird diagnostic output. It is preferable to // have an incomplete span than a completely nonsensical one. if span_data.ctxt != end_data.ctxt { if span_data.ctxt == SyntaxContext::root() { return end; } else if end_data.ctxt == SyntaxContext::root() { return self; } // Both spans fall within a macro. // FIXME(estebank): check if it is the *same* macro. } Span::new( cmp::min(span_data.lo, end_data.lo), cmp::max(span_data.hi, end_data.hi), if span_data.ctxt == SyntaxContext::root() { end_data.ctxt } else { span_data.ctxt }, ) } /// Returns a `Span` between the end of `self` to the beginning of `end`. pub fn between(self, end: Span) -> Span { let span = self.data(); let end = end.data(); Span::new( span.hi, end.lo, if end.ctxt == SyntaxContext::root() { end.ctxt } else { span.ctxt }, ) } /// Returns a `Span` between the beginning of `self` to the beginning of `end`. pub fn until(self, end: Span) -> Span { let span = self.data(); let end = end.data(); Span::new( span.lo, end.lo, if end.ctxt == SyntaxContext::root() { end.ctxt } else { span.ctxt }, ) } pub fn from_inner(self, inner: InnerSpan) -> Span { let span = self.data(); Span::new(span.lo + BytePos::from_usize(inner.start), span.lo + BytePos::from_usize(inner.end), span.ctxt) } /// Equivalent of `Span::def_site` from the proc macro API, /// except that the location is taken from the `self` span. pub fn with_def_site_ctxt(self, expn_id: ExpnId) -> Span { self.with_ctxt_from_mark(expn_id, Transparency::Opaque) } /// Equivalent of `Span::call_site` from the proc macro API, /// except that the location is taken from the `self` span. pub fn with_call_site_ctxt(&self, expn_id: ExpnId) -> Span { self.with_ctxt_from_mark(expn_id, Transparency::Transparent) } /// Span with a context reproducing `macro_rules` hygiene (hygienic locals, unhygienic items). /// FIXME: This should be eventually replaced either with `with_def_site_ctxt` (preferably), /// or with `with_call_site_ctxt` (where necessary). pub fn with_legacy_ctxt(&self, expn_id: ExpnId) -> Span { self.with_ctxt_from_mark(expn_id, Transparency::SemiTransparent) } /// Produces a span with the same location as `self` and context produced by a macro with the /// given ID and transparency, assuming that macro was defined directly and not produced by /// some other macro (which is the case for built-in and procedural macros). pub fn with_ctxt_from_mark(self, expn_id: ExpnId, transparency: Transparency) -> Span { self.with_ctxt(SyntaxContext::root().apply_mark(expn_id, transparency)) } #[inline] pub fn apply_mark(self, expn_id: ExpnId, transparency: Transparency) -> Span { let span = self.data(); span.with_ctxt(span.ctxt.apply_mark(expn_id, transparency)) } #[inline] pub fn remove_mark(&mut self) -> ExpnId { let mut span = self.data(); let mark = span.ctxt.remove_mark(); *self = Span::new(span.lo, span.hi, span.ctxt); mark } #[inline] pub fn adjust(&mut self, expn_id: ExpnId) -> Option { let mut span = self.data(); let mark = span.ctxt.adjust(expn_id); *self = Span::new(span.lo, span.hi, span.ctxt); mark } #[inline] pub fn modernize_and_adjust(&mut self, expn_id: ExpnId) -> Option { let mut span = self.data(); let mark = span.ctxt.modernize_and_adjust(expn_id); *self = Span::new(span.lo, span.hi, span.ctxt); mark } #[inline] pub fn glob_adjust(&mut self, expn_id: ExpnId, glob_span: Span) -> Option> { let mut span = self.data(); let mark = span.ctxt.glob_adjust(expn_id, glob_span); *self = Span::new(span.lo, span.hi, span.ctxt); mark } #[inline] pub fn reverse_glob_adjust(&mut self, expn_id: ExpnId, glob_span: Span) -> Option> { let mut span = self.data(); let mark = span.ctxt.reverse_glob_adjust(expn_id, glob_span); *self = Span::new(span.lo, span.hi, span.ctxt); mark } #[inline] pub fn modern(self) -> Span { let span = self.data(); span.with_ctxt(span.ctxt.modern()) } #[inline] pub fn modern_and_legacy(self) -> Span { let span = self.data(); span.with_ctxt(span.ctxt.modern_and_legacy()) } } #[derive(Clone, Debug)] pub struct SpanLabel { /// The span we are going to include in the final snippet. pub span: Span, /// Is this a primary span? This is the "locus" of the message, /// and is indicated with a `^^^^` underline, versus `----`. pub is_primary: bool, /// What label should we attach to this span (if any)? pub label: Option, } impl Default for Span { fn default() -> Self { DUMMY_SP } } impl rustc_serialize::UseSpecializedEncodable for Span { fn default_encode(&self, s: &mut S) -> Result<(), S::Error> { let span = self.data(); s.emit_struct("Span", 2, |s| { s.emit_struct_field("lo", 0, |s| { span.lo.encode(s) })?; s.emit_struct_field("hi", 1, |s| { span.hi.encode(s) }) }) } } impl rustc_serialize::UseSpecializedDecodable for Span { fn default_decode(d: &mut D) -> Result { d.read_struct("Span", 2, |d| { let lo = d.read_struct_field("lo", 0, Decodable::decode)?; let hi = d.read_struct_field("hi", 1, Decodable::decode)?; Ok(Span::with_root_ctxt(lo, hi)) }) } } pub fn default_span_debug(span: Span, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.debug_struct("Span") .field("lo", &span.lo()) .field("hi", &span.hi()) .field("ctxt", &span.ctxt()) .finish() } impl fmt::Debug for Span { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { SPAN_DEBUG.with(|span_debug| span_debug.get()(*self, f)) } } impl fmt::Debug for SpanData { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { SPAN_DEBUG.with(|span_debug| span_debug.get()(Span::new(self.lo, self.hi, self.ctxt), f)) } } impl MultiSpan { #[inline] pub fn new() -> MultiSpan { MultiSpan { primary_spans: vec![], span_labels: vec![] } } pub fn from_span(primary_span: Span) -> MultiSpan { MultiSpan { primary_spans: vec![primary_span], span_labels: vec![] } } pub fn from_spans(vec: Vec) -> MultiSpan { MultiSpan { primary_spans: vec, span_labels: vec![] } } pub fn push_span_label(&mut self, span: Span, label: String) { self.span_labels.push((span, label)); } /// Selects the first primary span (if any). pub fn primary_span(&self) -> Option { self.primary_spans.first().cloned() } /// Returns all primary spans. pub fn primary_spans(&self) -> &[Span] { &self.primary_spans } /// Returns `true` if any of the primary spans are displayable. pub fn has_primary_spans(&self) -> bool { self.primary_spans.iter().any(|sp| !sp.is_dummy()) } /// Returns `true` if this contains only a dummy primary span with any hygienic context. pub fn is_dummy(&self) -> bool { let mut is_dummy = true; for span in &self.primary_spans { if !span.is_dummy() { is_dummy = false; } } is_dummy } /// Replaces all occurrences of one Span with another. Used to move `Span`s in areas that don't /// display well (like std macros). Returns whether replacements occurred. pub fn replace(&mut self, before: Span, after: Span) -> bool { let mut replacements_occurred = false; for primary_span in &mut self.primary_spans { if *primary_span == before { *primary_span = after; replacements_occurred = true; } } for span_label in &mut self.span_labels { if span_label.0 == before { span_label.0 = after; replacements_occurred = true; } } replacements_occurred } /// Returns the strings to highlight. We always ensure that there /// is an entry for each of the primary spans -- for each primary /// span `P`, if there is at least one label with span `P`, we return /// those labels (marked as primary). But otherwise we return /// `SpanLabel` instances with empty labels. pub fn span_labels(&self) -> Vec { let is_primary = |span| self.primary_spans.contains(&span); let mut span_labels = self.span_labels.iter().map(|&(span, ref label)| SpanLabel { span, is_primary: is_primary(span), label: Some(label.clone()) } ).collect::>(); for &span in &self.primary_spans { if !span_labels.iter().any(|sl| sl.span == span) { span_labels.push(SpanLabel { span, is_primary: true, label: None }); } } span_labels } /// Returns `true` if any of the span labels is displayable. pub fn has_span_labels(&self) -> bool { self.span_labels.iter().any(|(sp, _)| !sp.is_dummy()) } } impl From for MultiSpan { fn from(span: Span) -> MultiSpan { MultiSpan::from_span(span) } } impl From> for MultiSpan { fn from(spans: Vec) -> MultiSpan { MultiSpan::from_spans(spans) } } /// Identifies an offset of a multi-byte character in a `SourceFile`. #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Eq, PartialEq, Debug)] pub struct MultiByteChar { /// The absolute offset of the character in the `SourceMap`. pub pos: BytePos, /// The number of bytes, `>= 2`. pub bytes: u8, } /// Identifies an offset of a non-narrow character in a `SourceFile`. #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Eq, PartialEq, Debug)] pub enum NonNarrowChar { /// Represents a zero-width character. ZeroWidth(BytePos), /// Represents a wide (full-width) character. Wide(BytePos), /// Represents a tab character, represented visually with a width of 4 characters. Tab(BytePos), } impl NonNarrowChar { fn new(pos: BytePos, width: usize) -> Self { match width { 0 => NonNarrowChar::ZeroWidth(pos), 2 => NonNarrowChar::Wide(pos), 4 => NonNarrowChar::Tab(pos), _ => panic!("width {} given for non-narrow character", width), } } /// Returns the absolute offset of the character in the `SourceMap`. pub fn pos(&self) -> BytePos { match *self { NonNarrowChar::ZeroWidth(p) | NonNarrowChar::Wide(p) | NonNarrowChar::Tab(p) => p, } } /// Returns the width of the character, 0 (zero-width) or 2 (wide). pub fn width(&self) -> usize { match *self { NonNarrowChar::ZeroWidth(_) => 0, NonNarrowChar::Wide(_) => 2, NonNarrowChar::Tab(_) => 4, } } } impl Add for NonNarrowChar { type Output = Self; fn add(self, rhs: BytePos) -> Self { match self { NonNarrowChar::ZeroWidth(pos) => NonNarrowChar::ZeroWidth(pos + rhs), NonNarrowChar::Wide(pos) => NonNarrowChar::Wide(pos + rhs), NonNarrowChar::Tab(pos) => NonNarrowChar::Tab(pos + rhs), } } } impl Sub for NonNarrowChar { type Output = Self; fn sub(self, rhs: BytePos) -> Self { match self { NonNarrowChar::ZeroWidth(pos) => NonNarrowChar::ZeroWidth(pos - rhs), NonNarrowChar::Wide(pos) => NonNarrowChar::Wide(pos - rhs), NonNarrowChar::Tab(pos) => NonNarrowChar::Tab(pos - rhs), } } } /// The state of the lazy external source loading mechanism of a `SourceFile`. #[derive(PartialEq, Eq, Clone)] pub enum ExternalSource { /// The external source has been loaded already. Present(String), /// No attempt has been made to load the external source. AbsentOk, /// A failed attempt has been made to load the external source. AbsentErr, /// No external source has to be loaded, since the `SourceFile` represents a local crate. Unneeded, } impl ExternalSource { pub fn is_absent(&self) -> bool { match *self { ExternalSource::Present(_) => false, _ => true, } } pub fn get_source(&self) -> Option<&str> { match *self { ExternalSource::Present(ref src) => Some(src), _ => None, } } } #[derive(Debug)] pub struct OffsetOverflowError; /// A single source in the `SourceMap`. #[derive(Clone)] pub struct SourceFile { /// The name of the file that the source came from, source that doesn't /// originate from files has names between angle brackets by convention /// (e.g., ``). pub name: FileName, /// `true` if the `name` field above has been modified by `--remap-path-prefix`. pub name_was_remapped: bool, /// The unmapped path of the file that the source came from. /// Set to `None` if the `SourceFile` was imported from an external crate. pub unmapped_path: Option, /// Indicates which crate this `SourceFile` was imported from. pub crate_of_origin: u32, /// The complete source code. pub src: Option>, /// The source code's hash. pub src_hash: u128, /// The external source code (used for external crates, which will have a `None` /// value as `self.src`. pub external_src: Lock, /// The start position of this source in the `SourceMap`. pub start_pos: BytePos, /// The end position of this source in the `SourceMap`. pub end_pos: BytePos, /// Locations of lines beginnings in the source code. pub lines: Vec, /// Locations of multi-byte characters in the source code. pub multibyte_chars: Vec, /// Width of characters that are not narrow in the source code. pub non_narrow_chars: Vec, /// A hash of the filename, used for speeding up hashing in incremental compilation. pub name_hash: u128, } impl Encodable for SourceFile { fn encode(&self, s: &mut S) -> Result<(), S::Error> { s.emit_struct("SourceFile", 8, |s| { s.emit_struct_field("name", 0, |s| self.name.encode(s))?; s.emit_struct_field("name_was_remapped", 1, |s| self.name_was_remapped.encode(s))?; s.emit_struct_field("src_hash", 2, |s| self.src_hash.encode(s))?; s.emit_struct_field("start_pos", 4, |s| self.start_pos.encode(s))?; s.emit_struct_field("end_pos", 5, |s| self.end_pos.encode(s))?; s.emit_struct_field("lines", 6, |s| { let lines = &self.lines[..]; // Store the length. s.emit_u32(lines.len() as u32)?; if !lines.is_empty() { // In order to preserve some space, we exploit the fact that // the lines list is sorted and individual lines are // probably not that long. Because of that we can store lines // as a difference list, using as little space as possible // for the differences. let max_line_length = if lines.len() == 1 { 0 } else { lines.windows(2) .map(|w| w[1] - w[0]) .map(|bp| bp.to_usize()) .max() .unwrap() }; let bytes_per_diff: u8 = match max_line_length { 0 ..= 0xFF => 1, 0x100 ..= 0xFFFF => 2, _ => 4 }; // Encode the number of bytes used per diff. bytes_per_diff.encode(s)?; // Encode the first element. lines[0].encode(s)?; let diff_iter = (&lines[..]).windows(2) .map(|w| (w[1] - w[0])); match bytes_per_diff { 1 => for diff in diff_iter { (diff.0 as u8).encode(s)? }, 2 => for diff in diff_iter { (diff.0 as u16).encode(s)? }, 4 => for diff in diff_iter { diff.0.encode(s)? }, _ => unreachable!() } } Ok(()) })?; s.emit_struct_field("multibyte_chars", 7, |s| { self.multibyte_chars.encode(s) })?; s.emit_struct_field("non_narrow_chars", 8, |s| { self.non_narrow_chars.encode(s) })?; s.emit_struct_field("name_hash", 9, |s| { self.name_hash.encode(s) }) }) } } impl Decodable for SourceFile { fn decode(d: &mut D) -> Result { d.read_struct("SourceFile", 8, |d| { let name: FileName = d.read_struct_field("name", 0, |d| Decodable::decode(d))?; let name_was_remapped: bool = d.read_struct_field("name_was_remapped", 1, |d| Decodable::decode(d))?; let src_hash: u128 = d.read_struct_field("src_hash", 2, |d| Decodable::decode(d))?; let start_pos: BytePos = d.read_struct_field("start_pos", 4, |d| Decodable::decode(d))?; let end_pos: BytePos = d.read_struct_field("end_pos", 5, |d| Decodable::decode(d))?; let lines: Vec = d.read_struct_field("lines", 6, |d| { let num_lines: u32 = Decodable::decode(d)?; let mut lines = Vec::with_capacity(num_lines as usize); if num_lines > 0 { // Read the number of bytes used per diff. let bytes_per_diff: u8 = Decodable::decode(d)?; // Read the first element. let mut line_start: BytePos = Decodable::decode(d)?; lines.push(line_start); for _ in 1..num_lines { let diff = match bytes_per_diff { 1 => d.read_u8()? as u32, 2 => d.read_u16()? as u32, 4 => d.read_u32()?, _ => unreachable!() }; line_start = line_start + BytePos(diff); lines.push(line_start); } } Ok(lines) })?; let multibyte_chars: Vec = d.read_struct_field("multibyte_chars", 7, |d| Decodable::decode(d))?; let non_narrow_chars: Vec = d.read_struct_field("non_narrow_chars", 8, |d| Decodable::decode(d))?; let name_hash: u128 = d.read_struct_field("name_hash", 9, |d| Decodable::decode(d))?; Ok(SourceFile { name, name_was_remapped, unmapped_path: None, // `crate_of_origin` has to be set by the importer. // This value matches up with rustc::hir::def_id::INVALID_CRATE. // That constant is not available here unfortunately :( crate_of_origin: std::u32::MAX - 1, start_pos, end_pos, src: None, src_hash, external_src: Lock::new(ExternalSource::AbsentOk), lines, multibyte_chars, non_narrow_chars, name_hash, }) }) } } impl fmt::Debug for SourceFile { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { write!(fmt, "SourceFile({})", self.name) } } impl SourceFile { pub fn new(name: FileName, name_was_remapped: bool, unmapped_path: FileName, mut src: String, start_pos: BytePos) -> Result { remove_bom(&mut src); normalize_newlines(&mut src); let src_hash = { let mut hasher: StableHasher = StableHasher::new(); hasher.write(src.as_bytes()); hasher.finish() }; let name_hash = { let mut hasher: StableHasher = StableHasher::new(); name.hash(&mut hasher); hasher.finish() }; let end_pos = start_pos.to_usize() + src.len(); if end_pos > u32::max_value() as usize { return Err(OffsetOverflowError); } let (lines, multibyte_chars, non_narrow_chars) = analyze_source_file::analyze_source_file(&src[..], start_pos); Ok(SourceFile { name, name_was_remapped, unmapped_path: Some(unmapped_path), crate_of_origin: 0, src: Some(Lrc::new(src)), src_hash, external_src: Lock::new(ExternalSource::Unneeded), start_pos, end_pos: Pos::from_usize(end_pos), lines, multibyte_chars, non_narrow_chars, name_hash, }) } /// Returns the `BytePos` of the beginning of the current line. pub fn line_begin_pos(&self, pos: BytePos) -> BytePos { let line_index = self.lookup_line(pos).unwrap(); self.lines[line_index] } /// Add externally loaded source. /// If the hash of the input doesn't match or no input is supplied via None, /// it is interpreted as an error and the corresponding enum variant is set. /// The return value signifies whether some kind of source is present. pub fn add_external_src(&self, get_src: F) -> bool where F: FnOnce() -> Option { if *self.external_src.borrow() == ExternalSource::AbsentOk { let src = get_src(); let mut external_src = self.external_src.borrow_mut(); // Check that no-one else have provided the source while we were getting it if *external_src == ExternalSource::AbsentOk { if let Some(src) = src { let mut hasher: StableHasher = StableHasher::new(); hasher.write(src.as_bytes()); if hasher.finish() == self.src_hash { *external_src = ExternalSource::Present(src); return true; } } else { *external_src = ExternalSource::AbsentErr; } false } else { self.src.is_some() || external_src.get_source().is_some() } } else { self.src.is_some() || self.external_src.borrow().get_source().is_some() } } /// Gets a line from the list of pre-computed line-beginnings. /// The line number here is 0-based. pub fn get_line(&self, line_number: usize) -> Option> { fn get_until_newline(src: &str, begin: usize) -> &str { // We can't use `lines.get(line_number+1)` because we might // be parsing when we call this function and thus the current // line is the last one we have line info for. let slice = &src[begin..]; match slice.find('\n') { Some(e) => &slice[..e], None => slice } } let begin = { let line = if let Some(line) = self.lines.get(line_number) { line } else { return None; }; let begin: BytePos = *line - self.start_pos; begin.to_usize() }; if let Some(ref src) = self.src { Some(Cow::from(get_until_newline(src, begin))) } else if let Some(src) = self.external_src.borrow().get_source() { Some(Cow::Owned(String::from(get_until_newline(src, begin)))) } else { None } } pub fn is_real_file(&self) -> bool { self.name.is_real() } pub fn is_imported(&self) -> bool { self.src.is_none() } pub fn byte_length(&self) -> u32 { self.end_pos.0 - self.start_pos.0 } pub fn count_lines(&self) -> usize { self.lines.len() } /// Finds the line containing the given position. The return value is the /// index into the `lines` array of this `SourceFile`, not the 1-based line /// number. If the source_file is empty or the position is located before the /// first line, `None` is returned. pub fn lookup_line(&self, pos: BytePos) -> Option { if self.lines.len() == 0 { return None; } let line_index = lookup_line(&self.lines[..], pos); assert!(line_index < self.lines.len() as isize); if line_index >= 0 { Some(line_index as usize) } else { None } } pub fn line_bounds(&self, line_index: usize) -> (BytePos, BytePos) { if self.start_pos == self.end_pos { return (self.start_pos, self.end_pos); } assert!(line_index < self.lines.len()); if line_index == (self.lines.len() - 1) { (self.lines[line_index], self.end_pos) } else { (self.lines[line_index], self.lines[line_index + 1]) } } #[inline] pub fn contains(&self, byte_pos: BytePos) -> bool { byte_pos >= self.start_pos && byte_pos <= self.end_pos } } /// Removes UTF-8 BOM, if any. fn remove_bom(src: &mut String) { if src.starts_with("\u{feff}") { src.drain(..3); } } /// Replaces `\r\n` with `\n` in-place in `src`. /// /// Returns error if there's a lone `\r` in the string fn normalize_newlines(src: &mut String) { if !src.as_bytes().contains(&b'\r') { return; } // We replace `\r\n` with `\n` in-place, which doesn't break utf-8 encoding. // While we *can* call `as_mut_vec` and do surgery on the live string // directly, let's rather steal the contents of `src`. This makes the code // safe even if a panic occurs. let mut buf = std::mem::replace(src, String::new()).into_bytes(); let mut gap_len = 0; let mut tail = buf.as_mut_slice(); loop { let idx = match find_crlf(&tail[gap_len..]) { None => tail.len(), Some(idx) => idx + gap_len, }; tail.copy_within(gap_len..idx, 0); tail = &mut tail[idx - gap_len..]; if tail.len() == gap_len { break; } gap_len += 1; } // Account for removed `\r`. // After `set_len`, `buf` is guaranteed to contain utf-8 again. let new_len = buf.len() - gap_len; unsafe { buf.set_len(new_len); *src = String::from_utf8_unchecked(buf); } fn find_crlf(src: &[u8]) -> Option { let mut search_idx = 0; while let Some(idx) = find_cr(&src[search_idx..]) { if src[search_idx..].get(idx + 1) != Some(&b'\n') { search_idx += idx + 1; continue; } return Some(search_idx + idx); } None } fn find_cr(src: &[u8]) -> Option { src.iter().position(|&b| b == b'\r') } } // _____________________________________________________________________________ // Pos, BytePos, CharPos // pub trait Pos { fn from_usize(n: usize) -> Self; fn to_usize(&self) -> usize; fn from_u32(n: u32) -> Self; fn to_u32(&self) -> u32; } /// A byte offset. Keep this small (currently 32-bits), as AST contains /// a lot of them. #[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Debug)] pub struct BytePos(pub u32); /// A character offset. Because of multibyte UTF-8 characters, a byte offset /// is not equivalent to a character offset. The `SourceMap` will convert `BytePos` /// values to `CharPos` values as necessary. #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Debug)] pub struct CharPos(pub usize); // FIXME: lots of boilerplate in these impls, but so far my attempts to fix // have been unsuccessful. impl Pos for BytePos { #[inline(always)] fn from_usize(n: usize) -> BytePos { BytePos(n as u32) } #[inline(always)] fn to_usize(&self) -> usize { self.0 as usize } #[inline(always)] fn from_u32(n: u32) -> BytePos { BytePos(n) } #[inline(always)] fn to_u32(&self) -> u32 { self.0 } } impl Add for BytePos { type Output = BytePos; #[inline(always)] fn add(self, rhs: BytePos) -> BytePos { BytePos((self.to_usize() + rhs.to_usize()) as u32) } } impl Sub for BytePos { type Output = BytePos; #[inline(always)] fn sub(self, rhs: BytePos) -> BytePos { BytePos((self.to_usize() - rhs.to_usize()) as u32) } } impl Encodable for BytePos { fn encode(&self, s: &mut S) -> Result<(), S::Error> { s.emit_u32(self.0) } } impl Decodable for BytePos { fn decode(d: &mut D) -> Result { Ok(BytePos(d.read_u32()?)) } } impl Pos for CharPos { #[inline(always)] fn from_usize(n: usize) -> CharPos { CharPos(n) } #[inline(always)] fn to_usize(&self) -> usize { self.0 } #[inline(always)] fn from_u32(n: u32) -> CharPos { CharPos(n as usize) } #[inline(always)] fn to_u32(&self) -> u32 { self.0 as u32} } impl Add for CharPos { type Output = CharPos; #[inline(always)] fn add(self, rhs: CharPos) -> CharPos { CharPos(self.to_usize() + rhs.to_usize()) } } impl Sub for CharPos { type Output = CharPos; #[inline(always)] fn sub(self, rhs: CharPos) -> CharPos { CharPos(self.to_usize() - rhs.to_usize()) } } // _____________________________________________________________________________ // Loc, SourceFileAndLine, SourceFileAndBytePos // /// A source code location used for error reporting. #[derive(Debug, Clone)] pub struct Loc { /// Information about the original source. pub file: Lrc, /// The (1-based) line number. pub line: usize, /// The (0-based) column offset. pub col: CharPos, /// The (0-based) column offset when displayed. pub col_display: usize, } // Used to be structural records. #[derive(Debug)] pub struct SourceFileAndLine { pub sf: Lrc, pub line: usize } #[derive(Debug)] pub struct SourceFileAndBytePos { pub sf: Lrc, pub pos: BytePos } #[derive(Copy, Clone, Debug, PartialEq, Eq)] pub struct LineInfo { /// Index of line, starting from 0. pub line_index: usize, /// Column in line where span begins, starting from 0. pub start_col: CharPos, /// Column in line where span ends, starting from 0, exclusive. pub end_col: CharPos, } pub struct FileLines { pub file: Lrc, pub lines: Vec } thread_local!(pub static SPAN_DEBUG: Cell) -> fmt::Result> = Cell::new(default_span_debug)); #[derive(Debug)] pub struct MacroBacktrace { /// span where macro was applied to generate this code pub call_site: Span, /// name of macro that was applied (e.g., "foo!" or "#[derive(Eq)]") pub macro_decl_name: String, /// span where macro was defined (possibly dummy) pub def_site_span: Span, } // _____________________________________________________________________________ // SpanLinesError, SpanSnippetError, DistinctSources, MalformedSourceMapPositions // pub type FileLinesResult = Result; #[derive(Clone, PartialEq, Eq, Debug)] pub enum SpanLinesError { IllFormedSpan(Span), DistinctSources(DistinctSources), } #[derive(Clone, PartialEq, Eq, Debug)] pub enum SpanSnippetError { IllFormedSpan(Span), DistinctSources(DistinctSources), MalformedForSourcemap(MalformedSourceMapPositions), SourceNotAvailable { filename: FileName } } #[derive(Clone, PartialEq, Eq, Debug)] pub struct DistinctSources { pub begin: (FileName, BytePos), pub end: (FileName, BytePos) } #[derive(Clone, PartialEq, Eq, Debug)] pub struct MalformedSourceMapPositions { pub name: FileName, pub source_len: usize, pub begin_pos: BytePos, pub end_pos: BytePos } /// Range inside of a `Span` used for diagnostics when we only have access to relative positions. #[derive(Copy, Clone, PartialEq, Eq, Debug)] pub struct InnerSpan { pub start: usize, pub end: usize, } impl InnerSpan { pub fn new(start: usize, end: usize) -> InnerSpan { InnerSpan { start, end } } } // Given a slice of line start positions and a position, returns the index of // the line the position is on. Returns -1 if the position is located before // the first line. fn lookup_line(lines: &[BytePos], pos: BytePos) -> isize { match lines.binary_search(&pos) { Ok(line) => line as isize, Err(line) => line as isize - 1 } }