1 // Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! The source positions and related helper functions
15 //! This API is completely unstable and subject to change.
17 #![crate_name = "syntax_pos"]
18 #![crate_type = "dylib"]
19 #![crate_type = "rlib"]
20 #![doc(html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
21 html_favicon_url = "https://doc.rust-lang.org/favicon.ico",
22 html_root_url = "https://doc.rust-lang.org/nightly/")]
26 #![feature(custom_attribute)]
27 #![feature(i128_type)]
28 #![feature(optin_builtin_traits)]
29 #![allow(unused_attributes)]
30 #![feature(specialization)]
32 #![cfg_attr(stage0, unstable(feature = "rustc_private", issue = "27812"))]
33 #![cfg_attr(stage0, feature(rustc_private))]
34 #![cfg_attr(stage0, feature(staged_api))]
36 use std::cell::{Cell, RefCell};
37 use std::ops::{Add, Sub};
41 use std::hash::Hasher;
43 use rustc_data_structures::stable_hasher::StableHasher;
45 extern crate rustc_data_structures;
47 use serialize::{Encodable, Decodable, Encoder, Decoder};
49 extern crate serialize;
50 extern crate serialize as rustc_serialize; // used by deriving
53 pub use hygiene::{SyntaxContext, ExpnInfo, ExpnFormat, NameAndSpan};
57 pub type FileName = String;
59 /// Spans represent a region of code, used for error reporting. Positions in spans
60 /// are *absolute* positions from the beginning of the codemap, not positions
61 /// relative to FileMaps. Methods on the CodeMap can be used to relate spans back
62 /// to the original source.
63 /// You must be careful if the span crosses more than one file - you will not be
64 /// able to use many of the functions on spans in codemap and you cannot assume
65 /// that the length of the span = hi - lo; there may be space in the BytePos
66 /// range between files.
67 #[derive(Clone, Copy, Hash, PartialEq, Eq, Ord, PartialOrd)]
71 /// Information about where the macro came from, if this piece of
72 /// code was created by a macro expansion.
73 pub ctxt: SyntaxContext,
76 /// A collection of spans. Spans have two orthogonal attributes:
78 /// - they can be *primary spans*. In this case they are the locus of
79 /// the error, and would be rendered with `^^^`.
80 /// - they can have a *label*. In this case, the label is written next
81 /// to the mark in the snippet when we render.
82 #[derive(Clone, Debug, Hash, PartialEq, Eq, RustcEncodable, RustcDecodable)]
83 pub struct MultiSpan {
84 primary_spans: Vec<Span>,
85 span_labels: Vec<(Span, String)>,
89 /// Returns a new span representing just the end-point of this span
90 pub fn end_point(self) -> Span {
91 let lo = cmp::max(self.hi.0 - 1, self.lo.0);
92 Span { lo: BytePos(lo), ..self }
95 /// Returns a new span representing the next character after the end-point of this span
96 pub fn next_point(self) -> Span {
97 let lo = cmp::max(self.hi.0, self.lo.0 + 1);
98 Span { lo: BytePos(lo), hi: BytePos(lo), ..self }
101 /// Returns `self` if `self` is not the dummy span, and `other` otherwise.
102 pub fn substitute_dummy(self, other: Span) -> Span {
103 if self.source_equal(&DUMMY_SP) { other } else { self }
106 pub fn contains(self, other: Span) -> bool {
107 self.lo <= other.lo && other.hi <= self.hi
110 /// Return true if the spans are equal with regards to the source text.
112 /// Use this instead of `==` when either span could be generated code,
113 /// and you only care that they point to the same bytes of source text.
114 pub fn source_equal(&self, other: &Span) -> bool {
115 self.lo == other.lo && self.hi == other.hi
118 /// Returns `Some(span)`, where the start is trimmed by the end of `other`
119 pub fn trim_start(self, other: Span) -> Option<Span> {
120 if self.hi > other.hi {
121 Some(Span { lo: cmp::max(self.lo, other.hi), .. self })
127 /// Return the source span - this is either the supplied span, or the span for
128 /// the macro callsite that expanded to it.
129 pub fn source_callsite(self) -> Span {
130 self.ctxt.outer().expn_info().map(|info| info.call_site.source_callsite()).unwrap_or(self)
133 /// Return the source callee.
135 /// Returns None if the supplied span has no expansion trace,
136 /// else returns the NameAndSpan for the macro definition
137 /// corresponding to the source callsite.
138 pub fn source_callee(self) -> Option<NameAndSpan> {
139 fn source_callee(info: ExpnInfo) -> NameAndSpan {
140 match info.call_site.ctxt.outer().expn_info() {
141 Some(info) => source_callee(info),
145 self.ctxt.outer().expn_info().map(source_callee)
148 /// Check if a span is "internal" to a macro in which #[unstable]
149 /// items can be used (that is, a macro marked with
150 /// `#[allow_internal_unstable]`).
151 pub fn allows_unstable(&self) -> bool {
152 match self.ctxt.outer().expn_info() {
153 Some(info) => info.callee.allow_internal_unstable,
158 pub fn macro_backtrace(mut self) -> Vec<MacroBacktrace> {
159 let mut prev_span = DUMMY_SP;
160 let mut result = vec![];
162 let info = match self.ctxt.outer().expn_info() {
167 let (pre, post) = match info.callee.format {
168 ExpnFormat::MacroAttribute(..) => ("#[", "]"),
169 ExpnFormat::MacroBang(..) => ("", "!"),
170 ExpnFormat::CompilerDesugaring(..) => ("desugaring of `", "`"),
172 let macro_decl_name = format!("{}{}{}", pre, info.callee.name(), post);
173 let def_site_span = info.callee.span;
175 // Don't print recursive invocations
176 if !info.call_site.source_equal(&prev_span) {
177 result.push(MacroBacktrace {
178 call_site: info.call_site,
179 macro_decl_name: macro_decl_name,
180 def_site_span: def_site_span,
185 self = info.call_site;
190 pub fn to(self, end: Span) -> Span {
191 // FIXME(jseyfried): self.ctxt should always equal end.ctxt here (c.f. issue #23480)
192 if end.ctxt == SyntaxContext::empty() {
193 Span { lo: self.lo, ..end }
195 Span { hi: end.hi, ..self }
199 pub fn between(self, end: Span) -> Span {
203 ctxt: if end.ctxt == SyntaxContext::empty() {
211 pub fn until(self, end: Span) -> Span {
215 ctxt: if end.ctxt == SyntaxContext::empty() {
224 #[derive(Clone, Debug)]
225 pub struct SpanLabel {
226 /// The span we are going to include in the final snippet.
229 /// Is this a primary span? This is the "locus" of the message,
230 /// and is indicated with a `^^^^` underline, versus `----`.
231 pub is_primary: bool,
233 /// What label should we attach to this span (if any)?
234 pub label: Option<String>,
237 impl serialize::UseSpecializedEncodable for Span {
238 fn default_encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
239 s.emit_struct("Span", 2, |s| {
240 s.emit_struct_field("lo", 0, |s| {
244 s.emit_struct_field("hi", 1, |s| {
251 impl serialize::UseSpecializedDecodable for Span {
252 fn default_decode<D: Decoder>(d: &mut D) -> Result<Span, D::Error> {
253 d.read_struct("Span", 2, |d| {
254 let lo = d.read_struct_field("lo", 0, Decodable::decode)?;
255 let hi = d.read_struct_field("hi", 1, Decodable::decode)?;
256 Ok(Span { lo: lo, hi: hi, ctxt: NO_EXPANSION })
261 fn default_span_debug(span: Span, f: &mut fmt::Formatter) -> fmt::Result {
262 write!(f, "Span {{ lo: {:?}, hi: {:?}, ctxt: {:?} }}",
263 span.lo, span.hi, span.ctxt)
266 impl fmt::Debug for Span {
267 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
268 SPAN_DEBUG.with(|span_debug| span_debug.get()(*self, f))
272 pub const DUMMY_SP: Span = Span { lo: BytePos(0), hi: BytePos(0), ctxt: NO_EXPANSION };
275 pub fn new() -> MultiSpan {
277 primary_spans: vec![],
282 pub fn from_span(primary_span: Span) -> MultiSpan {
284 primary_spans: vec![primary_span],
289 pub fn from_spans(vec: Vec<Span>) -> MultiSpan {
296 pub fn push_span_label(&mut self, span: Span, label: String) {
297 self.span_labels.push((span, label));
300 /// Selects the first primary span (if any)
301 pub fn primary_span(&self) -> Option<Span> {
302 self.primary_spans.first().cloned()
305 /// Returns all primary spans.
306 pub fn primary_spans(&self) -> &[Span] {
310 /// Replaces all occurances of one Span with another. Used to move Spans in areas that don't
311 /// display well (like std macros). Returns true if replacements occurred.
312 pub fn replace(&mut self, before: Span, after: Span) -> bool {
313 let mut replacements_occurred = false;
314 for primary_span in &mut self.primary_spans {
315 if *primary_span == before {
316 *primary_span = after;
317 replacements_occurred = true;
320 for span_label in &mut self.span_labels {
321 if span_label.0 == before {
322 span_label.0 = after;
323 replacements_occurred = true;
326 replacements_occurred
329 /// Returns the strings to highlight. We always ensure that there
330 /// is an entry for each of the primary spans -- for each primary
331 /// span P, if there is at least one label with span P, we return
332 /// those labels (marked as primary). But otherwise we return
333 /// `SpanLabel` instances with empty labels.
334 pub fn span_labels(&self) -> Vec<SpanLabel> {
335 let is_primary = |span| self.primary_spans.contains(&span);
336 let mut span_labels = vec![];
338 for &(span, ref label) in &self.span_labels {
339 span_labels.push(SpanLabel {
341 is_primary: is_primary(span),
342 label: Some(label.clone())
346 for &span in &self.primary_spans {
347 if !span_labels.iter().any(|sl| sl.span == span) {
348 span_labels.push(SpanLabel {
360 impl From<Span> for MultiSpan {
361 fn from(span: Span) -> MultiSpan {
362 MultiSpan::from_span(span)
366 pub const NO_EXPANSION: SyntaxContext = SyntaxContext::empty();
368 /// Identifies an offset of a multi-byte character in a FileMap
369 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Eq, PartialEq)]
370 pub struct MultiByteChar {
371 /// The absolute offset of the character in the CodeMap
373 /// The number of bytes, >=2
377 #[derive(PartialEq, Eq, Clone)]
378 pub enum ExternalSource {
385 /// A single source in the CodeMap.
388 /// The name of the file that the source came from, source that doesn't
389 /// originate from files has names between angle brackets by convention,
392 /// True if the `name` field above has been modified by -Zremap-path-prefix
393 pub name_was_remapped: bool,
394 /// Indicates which crate this FileMap was imported from.
395 pub crate_of_origin: u32,
396 /// The complete source code
397 pub src: Option<Rc<String>>,
398 /// The source code's hash
400 /// The external source code (used for external crates, which will have a `None`
401 /// value as `self.src`.
402 pub external_src: RefCell<ExternalSource>,
403 /// The start position of this source in the CodeMap
404 pub start_pos: BytePos,
405 /// The end position of this source in the CodeMap
406 pub end_pos: BytePos,
407 /// Locations of lines beginnings in the source code
408 pub lines: RefCell<Vec<BytePos>>,
409 /// Locations of multi-byte characters in the source code
410 pub multibyte_chars: RefCell<Vec<MultiByteChar>>,
413 impl Encodable for FileMap {
414 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
415 s.emit_struct("FileMap", 7, |s| {
416 s.emit_struct_field("name", 0, |s| self.name.encode(s))?;
417 s.emit_struct_field("name_was_remapped", 1, |s| self.name_was_remapped.encode(s))?;
418 s.emit_struct_field("src_hash", 6, |s| self.src_hash.encode(s))?;
419 s.emit_struct_field("start_pos", 2, |s| self.start_pos.encode(s))?;
420 s.emit_struct_field("end_pos", 3, |s| self.end_pos.encode(s))?;
421 s.emit_struct_field("lines", 4, |s| {
422 let lines = self.lines.borrow();
424 s.emit_u32(lines.len() as u32)?;
426 if !lines.is_empty() {
427 // In order to preserve some space, we exploit the fact that
428 // the lines list is sorted and individual lines are
429 // probably not that long. Because of that we can store lines
430 // as a difference list, using as little space as possible
431 // for the differences.
432 let max_line_length = if lines.len() == 1 {
436 .map(|w| w[1] - w[0])
437 .map(|bp| bp.to_usize())
442 let bytes_per_diff: u8 = match max_line_length {
444 0x100 ... 0xFFFF => 2,
448 // Encode the number of bytes used per diff.
449 bytes_per_diff.encode(s)?;
451 // Encode the first element.
454 let diff_iter = (&lines[..]).windows(2)
455 .map(|w| (w[1] - w[0]));
457 match bytes_per_diff {
458 1 => for diff in diff_iter { (diff.0 as u8).encode(s)? },
459 2 => for diff in diff_iter { (diff.0 as u16).encode(s)? },
460 4 => for diff in diff_iter { diff.0.encode(s)? },
467 s.emit_struct_field("multibyte_chars", 5, |s| {
468 (*self.multibyte_chars.borrow()).encode(s)
474 impl Decodable for FileMap {
475 fn decode<D: Decoder>(d: &mut D) -> Result<FileMap, D::Error> {
477 d.read_struct("FileMap", 6, |d| {
478 let name: String = d.read_struct_field("name", 0, |d| Decodable::decode(d))?;
479 let name_was_remapped: bool =
480 d.read_struct_field("name_was_remapped", 1, |d| Decodable::decode(d))?;
482 d.read_struct_field("src_hash", 6, |d| Decodable::decode(d))?;
483 let start_pos: BytePos =
484 d.read_struct_field("start_pos", 2, |d| Decodable::decode(d))?;
485 let end_pos: BytePos = d.read_struct_field("end_pos", 3, |d| Decodable::decode(d))?;
486 let lines: Vec<BytePos> = d.read_struct_field("lines", 4, |d| {
487 let num_lines: u32 = Decodable::decode(d)?;
488 let mut lines = Vec::with_capacity(num_lines as usize);
491 // Read the number of bytes used per diff.
492 let bytes_per_diff: u8 = Decodable::decode(d)?;
494 // Read the first element.
495 let mut line_start: BytePos = Decodable::decode(d)?;
496 lines.push(line_start);
498 for _ in 1..num_lines {
499 let diff = match bytes_per_diff {
500 1 => d.read_u8()? as u32,
501 2 => d.read_u16()? as u32,
506 line_start = line_start + BytePos(diff);
508 lines.push(line_start);
514 let multibyte_chars: Vec<MultiByteChar> =
515 d.read_struct_field("multibyte_chars", 5, |d| Decodable::decode(d))?;
518 name_was_remapped: name_was_remapped,
519 // `crate_of_origin` has to be set by the importer.
520 // This value matches up with rustc::hir::def_id::INVALID_CRATE.
521 // That constant is not available here unfortunately :(
522 crate_of_origin: ::std::u32::MAX - 1,
523 start_pos: start_pos,
527 external_src: RefCell::new(ExternalSource::AbsentOk),
528 lines: RefCell::new(lines),
529 multibyte_chars: RefCell::new(multibyte_chars)
535 impl fmt::Debug for FileMap {
536 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
537 write!(fmt, "FileMap({})", self.name)
542 pub fn new(name: FileName,
543 name_was_remapped: bool,
545 start_pos: BytePos) -> FileMap {
546 remove_bom(&mut src);
548 let mut hasher: StableHasher<u128> = StableHasher::new();
549 hasher.write(src.as_bytes());
550 let src_hash = hasher.finish();
552 let end_pos = start_pos.to_usize() + src.len();
556 name_was_remapped: name_was_remapped,
558 src: Some(Rc::new(src)),
560 external_src: RefCell::new(ExternalSource::Unneeded),
561 start_pos: start_pos,
562 end_pos: Pos::from_usize(end_pos),
563 lines: RefCell::new(Vec::new()),
564 multibyte_chars: RefCell::new(Vec::new()),
568 /// EFFECT: register a start-of-line offset in the
569 /// table of line-beginnings.
570 /// UNCHECKED INVARIANT: these offsets must be added in the right
571 /// order and must be in the right places; there is shared knowledge
572 /// about what ends a line between this file and parse.rs
573 /// WARNING: pos param here is the offset relative to start of CodeMap,
574 /// and CodeMap will append a newline when adding a filemap without a newline at the end,
575 /// so the safe way to call this is with value calculated as
576 /// filemap.start_pos + newline_offset_relative_to_the_start_of_filemap.
577 pub fn next_line(&self, pos: BytePos) {
578 // the new charpos must be > the last one (or it's the first one).
579 let mut lines = self.lines.borrow_mut();
580 let line_len = lines.len();
581 assert!(line_len == 0 || ((*lines)[line_len - 1] < pos));
585 /// get a line from the list of pre-computed line-beginnings.
586 /// line-number here is 0-based.
587 pub fn get_line(&self, line_number: usize) -> Option<&str> {
590 let lines = self.lines.borrow();
591 lines.get(line_number).map(|&line| {
592 let begin: BytePos = line - self.start_pos;
593 let begin = begin.to_usize();
594 // We can't use `lines.get(line_number+1)` because we might
595 // be parsing when we call this function and thus the current
596 // line is the last one we have line info for.
597 let slice = &src[begin..];
598 match slice.find('\n') {
599 Some(e) => &slice[..e],
608 pub fn record_multibyte_char(&self, pos: BytePos, bytes: usize) {
609 assert!(bytes >=2 && bytes <= 4);
610 let mbc = MultiByteChar {
614 self.multibyte_chars.borrow_mut().push(mbc);
617 pub fn is_real_file(&self) -> bool {
618 !(self.name.starts_with("<") &&
619 self.name.ends_with(">"))
622 pub fn is_imported(&self) -> bool {
626 pub fn byte_length(&self) -> u32 {
627 self.end_pos.0 - self.start_pos.0
629 pub fn count_lines(&self) -> usize {
630 self.lines.borrow().len()
633 /// Find the line containing the given position. The return value is the
634 /// index into the `lines` array of this FileMap, not the 1-based line
635 /// number. If the filemap is empty or the position is located before the
636 /// first line, None is returned.
637 pub fn lookup_line(&self, pos: BytePos) -> Option<usize> {
638 let lines = self.lines.borrow();
639 if lines.len() == 0 {
643 let line_index = lookup_line(&lines[..], pos);
644 assert!(line_index < lines.len() as isize);
646 Some(line_index as usize)
652 pub fn line_bounds(&self, line_index: usize) -> (BytePos, BytePos) {
653 if self.start_pos == self.end_pos {
654 return (self.start_pos, self.end_pos);
657 let lines = self.lines.borrow();
658 assert!(line_index < lines.len());
659 if line_index == (lines.len() - 1) {
660 (lines[line_index], self.end_pos)
662 (lines[line_index], lines[line_index + 1])
667 /// Remove utf-8 BOM if any.
668 fn remove_bom(src: &mut String) {
669 if src.starts_with("\u{feff}") {
674 // _____________________________________________________________________________
675 // Pos, BytePos, CharPos
679 fn from_usize(n: usize) -> Self;
680 fn to_usize(&self) -> usize;
683 /// A byte offset. Keep this small (currently 32-bits), as AST contains
685 #[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Debug)]
686 pub struct BytePos(pub u32);
688 /// A character offset. Because of multibyte utf8 characters, a byte offset
689 /// is not equivalent to a character offset. The CodeMap will convert BytePos
690 /// values to CharPos values as necessary.
691 #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord, Debug)]
692 pub struct CharPos(pub usize);
694 // FIXME: Lots of boilerplate in these impls, but so far my attempts to fix
695 // have been unsuccessful
697 impl Pos for BytePos {
698 fn from_usize(n: usize) -> BytePos { BytePos(n as u32) }
699 fn to_usize(&self) -> usize { let BytePos(n) = *self; n as usize }
702 impl Add for BytePos {
703 type Output = BytePos;
705 fn add(self, rhs: BytePos) -> BytePos {
706 BytePos((self.to_usize() + rhs.to_usize()) as u32)
710 impl Sub for BytePos {
711 type Output = BytePos;
713 fn sub(self, rhs: BytePos) -> BytePos {
714 BytePos((self.to_usize() - rhs.to_usize()) as u32)
718 impl Encodable for BytePos {
719 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
724 impl Decodable for BytePos {
725 fn decode<D: Decoder>(d: &mut D) -> Result<BytePos, D::Error> {
726 Ok(BytePos(d.read_u32()?))
730 impl Pos for CharPos {
731 fn from_usize(n: usize) -> CharPos { CharPos(n) }
732 fn to_usize(&self) -> usize { let CharPos(n) = *self; n }
735 impl Add for CharPos {
736 type Output = CharPos;
738 fn add(self, rhs: CharPos) -> CharPos {
739 CharPos(self.to_usize() + rhs.to_usize())
743 impl Sub for CharPos {
744 type Output = CharPos;
746 fn sub(self, rhs: CharPos) -> CharPos {
747 CharPos(self.to_usize() - rhs.to_usize())
751 // _____________________________________________________________________________
752 // Loc, LocWithOpt, FileMapAndLine, FileMapAndBytePos
755 /// A source code location used for error reporting
756 #[derive(Debug, Clone)]
758 /// Information about the original source
759 pub file: Rc<FileMap>,
760 /// The (1-based) line number
762 /// The (0-based) column offset
766 /// A source code location used as the result of lookup_char_pos_adj
767 // Actually, *none* of the clients use the filename *or* file field;
768 // perhaps they should just be removed.
770 pub struct LocWithOpt {
771 pub filename: FileName,
774 pub file: Option<Rc<FileMap>>,
777 // used to be structural records. Better names, anyone?
779 pub struct FileMapAndLine { pub fm: Rc<FileMap>, pub line: usize }
781 pub struct FileMapAndBytePos { pub fm: Rc<FileMap>, pub pos: BytePos }
783 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
784 pub struct LineInfo {
785 /// Index of line, starting from 0.
786 pub line_index: usize,
788 /// Column in line where span begins, starting from 0.
789 pub start_col: CharPos,
791 /// Column in line where span ends, starting from 0, exclusive.
792 pub end_col: CharPos,
795 pub struct FileLines {
796 pub file: Rc<FileMap>,
797 pub lines: Vec<LineInfo>
800 thread_local!(pub static SPAN_DEBUG: Cell<fn(Span, &mut fmt::Formatter) -> fmt::Result> =
801 Cell::new(default_span_debug));
803 pub struct MacroBacktrace {
804 /// span where macro was applied to generate this code
807 /// name of macro that was applied (e.g., "foo!" or "#[derive(Eq)]")
808 pub macro_decl_name: String,
810 /// span where macro was defined (if known)
811 pub def_site_span: Option<Span>,
814 // _____________________________________________________________________________
815 // SpanLinesError, SpanSnippetError, DistinctSources, MalformedCodemapPositions
818 pub type FileLinesResult = Result<FileLines, SpanLinesError>;
820 #[derive(Clone, PartialEq, Eq, Debug)]
821 pub enum SpanLinesError {
823 DistinctSources(DistinctSources),
826 #[derive(Clone, PartialEq, Eq, Debug)]
827 pub enum SpanSnippetError {
829 DistinctSources(DistinctSources),
830 MalformedForCodemap(MalformedCodemapPositions),
831 SourceNotAvailable { filename: String }
834 #[derive(Clone, PartialEq, Eq, Debug)]
835 pub struct DistinctSources {
836 pub begin: (String, BytePos),
837 pub end: (String, BytePos)
840 #[derive(Clone, PartialEq, Eq, Debug)]
841 pub struct MalformedCodemapPositions {
843 pub source_len: usize,
844 pub begin_pos: BytePos,
848 // Given a slice of line start positions and a position, returns the index of
849 // the line the position is on. Returns -1 if the position is located before
851 fn lookup_line(lines: &[BytePos], pos: BytePos) -> isize {
852 match lines.binary_search(&pos) {
853 Ok(line) => line as isize,
854 Err(line) => line as isize - 1
860 use super::{lookup_line, BytePos};
863 fn test_lookup_line() {
865 let lines = &[BytePos(3), BytePos(17), BytePos(28)];
867 assert_eq!(lookup_line(lines, BytePos(0)), -1);
868 assert_eq!(lookup_line(lines, BytePos(3)), 0);
869 assert_eq!(lookup_line(lines, BytePos(4)), 0);
871 assert_eq!(lookup_line(lines, BytePos(16)), 0);
872 assert_eq!(lookup_line(lines, BytePos(17)), 1);
873 assert_eq!(lookup_line(lines, BytePos(18)), 1);
875 assert_eq!(lookup_line(lines, BytePos(28)), 2);
876 assert_eq!(lookup_line(lines, BytePos(29)), 2);