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rust/src/libsyntax_pos/lib.rs

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// Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! The source positions and related helper functions
//!
//! # Note
//!
//! This API is completely unstable and subject to change.
#![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
html_root_url = "https://doc.rust-lang.org/nightly/")]
#![feature(const_fn)]
#![feature(custom_attribute)]
#![feature(optin_builtin_traits)]
#![allow(unused_attributes)]
#![feature(specialization)]
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;
use rustc_data_structures::stable_hasher::StableHasher;
use rustc_data_structures::sync::{Lrc, Lock};
extern crate arena;
extern crate rustc_data_structures;
#[macro_use]
extern crate scoped_tls;
use serialize::{Encodable, Decodable, Encoder, Decoder};
extern crate serialize;
extern crate serialize as rustc_serialize; // used by deriving
extern crate unicode_width;
pub mod hygiene;
pub use hygiene::{Mark, SyntaxContext, ExpnInfo, ExpnFormat, NameAndSpan, CompilerDesugaringKind};
mod span_encoding;
pub use span_encoding::{Span, DUMMY_SP};
pub mod symbol;
pub struct Globals {
symbol_interner: Lock<symbol::Interner>,
span_interner: Lock<span_encoding::SpanInterner>,
hygiene_data: Lock<hygiene::HygieneData>,
}
impl Globals {
pub fn new() -> Globals {
Globals {
symbol_interner: Lock::new(symbol::Interner::fresh()),
span_interner: Lock::new(span_encoding::SpanInterner::default()),
hygiene_data: Lock::new(hygiene::HygieneData::new()),
}
}
}
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),
/// e.g. "std" macros
Macros(String),
/// call to `quote!`
QuoteExpansion,
/// Command line
Anon,
/// Hack in src/libsyntax/parse.rs
/// FIXME(jseyfried)
MacroExpansion,
ProcMacroSourceCode,
/// Strings provided as --cfg [cfgspec] stored in a crate_cfg
CfgSpec,
/// Custom sources for explicit parser calls from plugins and drivers
Custom(String),
}
impl std::fmt::Display for FileName {
fn fmt(&self, fmt: &mut std::fmt::Formatter) -> std::fmt::Result {
use self::FileName::*;
match *self {
Real(ref path) => write!(fmt, "{}", path.display()),
Macros(ref name) => write!(fmt, "<{} macros>", name),
QuoteExpansion => write!(fmt, "<quote expansion>"),
MacroExpansion => write!(fmt, "<macro expansion>"),
Anon => write!(fmt, "<anon>"),
ProcMacroSourceCode => write!(fmt, "<proc-macro source code>"),
CfgSpec => write!(fmt, "cfgspec"),
Custom(ref s) => write!(fmt, "<{}>", s),
}
}
}
impl From<PathBuf> 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 self::FileName::*;
match *self {
Real(_) => true,
Macros(_) |
Anon |
MacroExpansion |
ProcMacroSourceCode |
CfgSpec |
Custom(_) |
QuoteExpansion => false,
}
}
pub fn is_macros(&self) -> bool {
use self::FileName::*;
match *self {
Real(_) |
Anon |
MacroExpansion |
ProcMacroSourceCode |
CfgSpec |
Custom(_) |
QuoteExpansion => false,
Macros(_) => true,
}
}
}
/// Spans represent a region of code, used for error reporting. Positions in spans
/// are *absolute* positions from the beginning of the codemap, not positions
/// relative to FileMaps. Methods on the CodeMap 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 codemap 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_queries))]
impl !Send for Span {}
#[cfg(not(parallel_queries))]
impl !Sync for Span {}
impl PartialOrd for Span {
fn partial_cmp(&self, rhs: &Self) -> Option<Ordering> {
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>,
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 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.source_equal(&DUMMY_SP) { other } else { self }
}
/// Return 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
}
/// Return 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<Span> {
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
}
}
/// Return 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 {
self.ctxt().outer().expn_info().map(|info| info.call_site.source_callsite()).unwrap_or(self)
}
/// The `Span` for the tokens in the previous macro expansion from which `self` was generated,
/// if any
pub fn parent(self) -> Option<Span> {
self.ctxt().outer().expn_info().map(|i| i.call_site)
}
/// Return the source callee.
///
/// Returns None if the supplied span has no expansion trace,
/// else returns the NameAndSpan for the macro definition
/// corresponding to the source callsite.
pub fn source_callee(self) -> Option<NameAndSpan> {
fn source_callee(info: ExpnInfo) -> NameAndSpan {
match info.call_site.ctxt().outer().expn_info() {
Some(info) => source_callee(info),
None => info.callee,
}
}
self.ctxt().outer().expn_info().map(source_callee)
}
/// Check 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) -> bool {
match self.ctxt().outer().expn_info() {
Some(info) => info.callee.allow_internal_unstable,
None => false,
}
}
/// Check if this span arises from a compiler desugaring of kind `kind`.
pub fn is_compiler_desugaring(&self, kind: CompilerDesugaringKind) -> bool {
match self.ctxt().outer().expn_info() {
Some(info) => match info.callee.format {
ExpnFormat::CompilerDesugaring(k) => k == kind,
_ => false,
},
None => false,
}
}
/// Return the compiler desugaring that created this span, or None
/// if this span is not from a desugaring.
pub fn compiler_desugaring_kind(&self) -> Option<CompilerDesugaringKind> {
match self.ctxt().outer().expn_info() {
Some(info) => match info.callee.format {
ExpnFormat::CompilerDesugaring(k) => Some(k),
_ => None
},
None => None
}
}
/// Check 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 {
match self.ctxt().outer().expn_info() {
Some(info) => info.callee.allow_internal_unsafe,
None => false,
}
}
pub fn macro_backtrace(mut self) -> Vec<MacroBacktrace> {
let mut prev_span = DUMMY_SP;
let mut result = vec![];
while let Some(info) = self.ctxt().outer().expn_info() {
let (pre, post) = match info.callee.format {
ExpnFormat::MacroAttribute(..) => ("#[", "]"),
ExpnFormat::MacroBang(..) => ("", "!"),
ExpnFormat::CompilerDesugaring(..) => ("desugaring of `", "`"),
};
let macro_decl_name = format!("{}{}{}", pre, info.callee.name(), post);
let def_site_span = info.callee.span;
// Don't print recursive invocations
if !info.call_site.source_equal(&prev_span) {
result.push(MacroBacktrace {
call_site: info.call_site,
macro_decl_name,
def_site_span,
});
}
prev_span = self;
self = info.call_site;
}
result
}
/// Return 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 (c.f. 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::empty() {
return end;
} else if end_data.ctxt == SyntaxContext::empty() {
return self;
}
// both span 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::empty() { end_data.ctxt } else { span_data.ctxt },
)
}
/// Return 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::empty() { end.ctxt } else { span.ctxt },
)
}
/// Return 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::empty() { end.ctxt } else { span.ctxt },
)
}
#[inline]
pub fn apply_mark(self, mark: Mark) -> Span {
let span = self.data();
span.with_ctxt(span.ctxt.apply_mark(mark))
}
#[inline]
pub fn remove_mark(&mut self) -> Mark {
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, expansion: Mark) -> Option<Mark> {
let mut span = self.data();
let mark = span.ctxt.adjust(expansion);
*self = Span::new(span.lo, span.hi, span.ctxt);
mark
}
#[inline]
pub fn glob_adjust(&mut self, expansion: Mark, glob_ctxt: SyntaxContext)
-> Option<Option<Mark>> {
let mut span = self.data();
let mark = span.ctxt.glob_adjust(expansion, glob_ctxt);
*self = Span::new(span.lo, span.hi, span.ctxt);
mark
}
#[inline]
pub fn reverse_glob_adjust(&mut self, expansion: Mark, glob_ctxt: SyntaxContext)
-> Option<Option<Mark>> {
let mut span = self.data();
let mark = span.ctxt.reverse_glob_adjust(expansion, glob_ctxt);
*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())
}
}
#[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<String>,
}
impl Default for Span {
fn default() -> Self {
DUMMY_SP
}
}
impl serialize::UseSpecializedEncodable for Span {
fn default_encode<S: Encoder>(&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 serialize::UseSpecializedDecodable for Span {
fn default_decode<D: Decoder>(d: &mut D) -> Result<Span, D::Error> {
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::new(lo, hi, NO_EXPANSION))
})
}
}
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 {
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<Span>) -> 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<Span> {
self.primary_spans.first().cloned()
}
/// Returns all primary spans.
pub fn primary_spans(&self) -> &[Span] {
&self.primary_spans
}
/// Replaces all occurrences of one Span with another. Used to move Spans in areas that don't
/// display well (like std macros). Returns true if 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<SpanLabel> {
let is_primary = |span| self.primary_spans.contains(&span);
let mut span_labels = vec![];
for &(span, ref label) in &self.span_labels {
span_labels.push(SpanLabel {
span,
is_primary: is_primary(span),
label: Some(label.clone())
});
}
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
}
}
impl From<Span> for MultiSpan {
fn from(span: Span) -> MultiSpan {
MultiSpan::from_span(span)
}
}
impl From<Vec<Span>> for MultiSpan {
fn from(spans: Vec<Span>) -> MultiSpan {
MultiSpan::from_spans(spans)
}
}
pub const NO_EXPANSION: SyntaxContext = SyntaxContext::empty();
/// Identifies an offset of a multi-byte character in a FileMap
#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Eq, PartialEq)]
pub struct MultiByteChar {
/// The absolute offset of the character in the CodeMap
pub pos: BytePos,
/// The number of bytes, >=2
pub bytes: usize,
}
/// Identifies an offset of a non-narrow character in a FileMap
#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Eq, PartialEq)]
pub enum NonNarrowChar {
/// Represents a zero-width character
ZeroWidth(BytePos),
/// Represents a wide (fullwidth) 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 CodeMap
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<BytePos> 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<BytePos> 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 FileMap.
#[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 FileMap 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,
}
}
}
/// A single source in the CodeMap.
#[derive(Clone)]
pub struct FileMap {
/// 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. `<anon>`
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 FileMap was imported from an external crate.
pub unmapped_path: Option<FileName>,
/// Indicates which crate this FileMap was imported from.
pub crate_of_origin: u32,
/// The complete source code
pub src: Option<Lrc<String>>,
/// 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<ExternalSource>,
/// The start position of this source in the CodeMap
pub start_pos: BytePos,
/// The end position of this source in the CodeMap
pub end_pos: BytePos,
/// Locations of lines beginnings in the source code
pub lines: Lock<Vec<BytePos>>,
/// Locations of multi-byte characters in the source code
pub multibyte_chars: Lock<Vec<MultiByteChar>>,
/// Width of characters that are not narrow in the source code
pub non_narrow_chars: Lock<Vec<NonNarrowChar>>,
/// A hash of the filename, used for speeding up the incr. comp. hashing.
pub name_hash: u128,
}
impl Encodable for FileMap {
fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
s.emit_struct("FileMap", 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.borrow();
// 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.borrow()).encode(s)
})?;
s.emit_struct_field("non_narrow_chars", 8, |s| {
(*self.non_narrow_chars.borrow()).encode(s)
})?;
s.emit_struct_field("name_hash", 9, |s| {
self.name_hash.encode(s)
})
})
}
}
impl Decodable for FileMap {
fn decode<D: Decoder>(d: &mut D) -> Result<FileMap, D::Error> {
d.read_struct("FileMap", 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<BytePos> = 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<MultiByteChar> =
d.read_struct_field("multibyte_chars", 7, |d| Decodable::decode(d))?;
let non_narrow_chars: Vec<NonNarrowChar> =
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(FileMap {
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: Lock::new(lines),
multibyte_chars: Lock::new(multibyte_chars),
non_narrow_chars: Lock::new(non_narrow_chars),
name_hash,
})
})
}
}
impl fmt::Debug for FileMap {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
write!(fmt, "FileMap({})", self.name)
}
}
impl FileMap {
pub fn new(name: FileName,
name_was_remapped: bool,
unmapped_path: FileName,
mut src: String,
start_pos: BytePos) -> FileMap {
remove_bom(&mut src);
let src_hash = {
let mut hasher: StableHasher<u128> = StableHasher::new();
hasher.write(src.as_bytes());
hasher.finish()
};
let name_hash = {
let mut hasher: StableHasher<u128> = StableHasher::new();
name.hash(&mut hasher);
hasher.finish()
};
let end_pos = start_pos.to_usize() + src.len();
FileMap {
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: Lock::new(Vec::new()),
multibyte_chars: Lock::new(Vec::new()),
non_narrow_chars: Lock::new(Vec::new()),
name_hash,
}
}
/// EFFECT: register a start-of-line offset in the
/// table of line-beginnings.
/// UNCHECKED INVARIANT: these offsets must be added in the right
/// order and must be in the right places; there is shared knowledge
/// about what ends a line between this file and parse.rs
/// WARNING: pos param here is the offset relative to start of CodeMap,
/// and CodeMap will append a newline when adding a filemap without a newline at the end,
/// so the safe way to call this is with value calculated as
/// filemap.start_pos + newline_offset_relative_to_the_start_of_filemap.
pub fn next_line(&self, pos: BytePos) {
// the new charpos must be > the last one (or it's the first one).
let mut lines = self.lines.borrow_mut();
let line_len = lines.len();
assert!(line_len == 0 || ((*lines)[line_len - 1] < pos));
lines.push(pos);
}
/// 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<F>(&self, get_src: F) -> bool
where F: FnOnce() -> Option<String>
{
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<u128> = 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()
}
}
/// Get 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<Cow<str>> {
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 lines = self.lines.borrow();
let line = if let Some(line) = 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 record_multibyte_char(&self, pos: BytePos, bytes: usize) {
assert!(bytes >=2 && bytes <= 4);
let mbc = MultiByteChar {
pos,
bytes,
};
self.multibyte_chars.borrow_mut().push(mbc);
}
pub fn record_width(&self, pos: BytePos, ch: char) {
let width = match ch {
'\t' =>
// Tabs will consume 4 columns.
4,
'\n' =>
// Make newlines take one column so that displayed spans can point them.
1,
ch =>
// Assume control characters are zero width.
// FIXME: How can we decide between `width` and `width_cjk`?
unicode_width::UnicodeWidthChar::width(ch).unwrap_or(0),
};
// Only record non-narrow characters.
if width != 1 {
self.non_narrow_chars.borrow_mut().push(NonNarrowChar::new(pos, width));
}
}
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.borrow().len()
}
/// Find the line containing the given position. The return value is the
/// index into the `lines` array of this FileMap, not the 1-based line
/// number. If the filemap is empty or the position is located before the
/// first line, None is returned.
pub fn lookup_line(&self, pos: BytePos) -> Option<usize> {
let lines = self.lines.borrow();
if lines.len() == 0 {
return None;
}
let line_index = lookup_line(&lines[..], pos);
assert!(line_index < 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);
}
let lines = self.lines.borrow();
assert!(line_index < lines.len());
if line_index == (lines.len() - 1) {
(lines[line_index], self.end_pos)
} else {
(lines[line_index], lines[line_index + 1])
}
}
#[inline]
pub fn contains(&self, byte_pos: BytePos) -> bool {
byte_pos >= self.start_pos && byte_pos <= self.end_pos
}
}
/// Remove utf-8 BOM if any.
fn remove_bom(src: &mut String) {
if src.starts_with("\u{feff}") {
src.drain(..3);
}
}
// _____________________________________________________________________________
// Pos, BytePos, CharPos
//
pub trait Pos {
fn from_usize(n: usize) -> Self;
fn to_usize(&self) -> usize;
}
/// 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 utf8 characters, a byte offset
/// is not equivalent to a character offset. The CodeMap 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 { let BytePos(n) = *self; n as usize }
}
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<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
s.emit_u32(self.0)
}
}
impl Decodable for BytePos {
fn decode<D: Decoder>(d: &mut D) -> Result<BytePos, D::Error> {
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 { let CharPos(n) = *self; n }
}
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, LocWithOpt, FileMapAndLine, FileMapAndBytePos
//
/// A source code location used for error reporting
#[derive(Debug, Clone)]
pub struct Loc {
/// Information about the original source
pub file: Lrc<FileMap>,
/// 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,
}
/// A source code location used as the result of lookup_char_pos_adj
// Actually, *none* of the clients use the filename *or* file field;
// perhaps they should just be removed.
#[derive(Debug)]
pub struct LocWithOpt {
pub filename: FileName,
pub line: usize,
pub col: CharPos,
pub file: Option<Lrc<FileMap>>,
}
// used to be structural records. Better names, anyone?
#[derive(Debug)]
pub struct FileMapAndLine { pub fm: Lrc<FileMap>, pub line: usize }
#[derive(Debug)]
pub struct FileMapAndBytePos { pub fm: Lrc<FileMap>, 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<FileMap>,
pub lines: Vec<LineInfo>
}
thread_local!(pub static SPAN_DEBUG: Cell<fn(Span, &mut fmt::Formatter) -> 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 (if known)
pub def_site_span: Option<Span>,
}
// _____________________________________________________________________________
// SpanLinesError, SpanSnippetError, DistinctSources, MalformedCodemapPositions
//
pub type FileLinesResult = Result<FileLines, SpanLinesError>;
#[derive(Clone, PartialEq, Eq, Debug)]
pub enum SpanLinesError {
IllFormedSpan(Span),
DistinctSources(DistinctSources),
}
#[derive(Clone, PartialEq, Eq, Debug)]
pub enum SpanSnippetError {
IllFormedSpan(Span),
DistinctSources(DistinctSources),
MalformedForCodemap(MalformedCodemapPositions),
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 MalformedCodemapPositions {
pub name: FileName,
pub source_len: usize,
pub begin_pos: BytePos,
pub end_pos: BytePos
}
// 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
}
}
#[cfg(test)]
mod tests {
use super::{lookup_line, BytePos};
#[test]
fn test_lookup_line() {
let lines = &[BytePos(3), BytePos(17), BytePos(28)];
assert_eq!(lookup_line(lines, BytePos(0)), -1);
assert_eq!(lookup_line(lines, BytePos(3)), 0);
assert_eq!(lookup_line(lines, BytePos(4)), 0);
assert_eq!(lookup_line(lines, BytePos(16)), 0);
assert_eq!(lookup_line(lines, BytePos(17)), 1);
assert_eq!(lookup_line(lines, BytePos(18)), 1);
assert_eq!(lookup_line(lines, BytePos(28)), 2);
assert_eq!(lookup_line(lines, BytePos(29)), 2);
}
}
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