// 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 or the MIT license // , 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/")] #![deny(warnings)] #![feature(const_fn)] #![feature(custom_attribute)] #![feature(i128_type)] #![feature(optin_builtin_traits)] #![allow(unused_attributes)] #![feature(specialization)] use std::borrow::Cow; use std::cell::{Cell, RefCell}; use std::cmp; use std::fmt; use std::hash::Hasher; use std::ops::{Add, Sub}; use std::rc::Rc; use rustc_data_structures::stable_hasher::StableHasher; extern crate rustc_data_structures; use serialize::{Encodable, Decodable, Encoder, Decoder}; extern crate serialize; extern crate serialize as rustc_serialize; // used by deriving pub mod hygiene; pub use hygiene::{SyntaxContext, ExpnInfo, ExpnFormat, NameAndSpan, CompilerDesugaringKind}; pub mod symbol; pub type FileName = String; /// 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. #[derive(Clone, Copy, Hash, PartialEq, Eq, Ord, PartialOrd)] pub struct Span { 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, } /// 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 { /// Returns a new span representing just the end-point of this span pub fn end_point(self) -> Span { let lo = cmp::max(self.hi.0 - 1, self.lo.0); Span { lo: BytePos(lo), ..self } } /// Returns a new span representing the next character after the end-point of this span pub fn next_point(self) -> Span { let lo = cmp::max(self.hi.0, self.lo.0 + 1); Span { lo: BytePos(lo), hi: BytePos(lo), ..self } } /// 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 { self.lo <= other.lo && other.hi <= self.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 { self.lo == other.lo && self.hi == other.hi } /// Returns `Some(span)`, where the start is trimmed by the end of `other` pub fn trim_start(self, other: Span) -> Option { if self.hi > other.hi { Some(Span { lo: cmp::max(self.lo, other.hi), .. self }) } 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) } /// 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 { 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, } } /// 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 { let mut prev_span = DUMMY_SP; let mut result = vec![]; loop { let info = match self.ctxt.outer().expn_info() { Some(info) => info, None => break, }; 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 { Span { lo: cmp::min(self.lo, end.lo), hi: cmp::max(self.hi, end.hi), // FIXME(jseyfried): self.ctxt should always equal end.ctxt here (c.f. issue #23480) ctxt: if self.ctxt == SyntaxContext::empty() { end.ctxt } else { self.ctxt }, } } /// Return a `Span` between the end of `self` to the beginning of `end`. pub fn between(self, end: Span) -> Span { Span { lo: self.hi, hi: end.lo, ctxt: if end.ctxt == SyntaxContext::empty() { end.ctxt } else { self.ctxt } } } /// Return a `Span` between the beginning of `self` to the beginning of `end`. pub fn until(self, end: Span) -> Span { Span { lo: self.lo, hi: end.lo, ctxt: if end.ctxt == SyntaxContext::empty() { end.ctxt } else { self.ctxt } } } } #[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 serialize::UseSpecializedEncodable for Span { fn default_encode(&self, s: &mut S) -> Result<(), S::Error> { s.emit_struct("Span", 2, |s| { s.emit_struct_field("lo", 0, |s| { self.lo.encode(s) })?; s.emit_struct_field("hi", 1, |s| { self.hi.encode(s) }) }) } } impl 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 { lo: lo, hi: hi, ctxt: NO_EXPANSION }) }) } } fn default_span_debug(span: Span, f: &mut fmt::Formatter) -> fmt::Result { write!(f, "Span {{ lo: {:?}, hi: {:?}, ctxt: {:?} }}", span.lo, span.hi, span.ctxt) } impl fmt::Debug for Span { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { SPAN_DEBUG.with(|span_debug| span_debug.get()(*self, f)) } } pub const DUMMY_SP: Span = Span { lo: BytePos(0), hi: BytePos(0), ctxt: NO_EXPANSION }; 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) -> 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 } /// 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 { 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 for MultiSpan { fn from(span: Span) -> MultiSpan { MultiSpan::from_span(span) } } 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, } /// 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. `` pub name: FileName, /// True if the `name` field above has been modified by -Zremap-path-prefix pub name_was_remapped: bool, /// Indicates which crate this FileMap 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: RefCell, /// 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: RefCell>, /// Locations of multi-byte characters in the source code pub multibyte_chars: RefCell>, } impl Encodable for FileMap { fn encode(&self, s: &mut S) -> Result<(), S::Error> { s.emit_struct("FileMap", 7, |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", 6, |s| self.src_hash.encode(s))?; s.emit_struct_field("start_pos", 2, |s| self.start_pos.encode(s))?; s.emit_struct_field("end_pos", 3, |s| self.end_pos.encode(s))?; s.emit_struct_field("lines", 4, |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", 5, |s| { (*self.multibyte_chars.borrow()).encode(s) }) }) } } impl Decodable for FileMap { fn decode(d: &mut D) -> Result { d.read_struct("FileMap", 6, |d| { let name: String = 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", 6, |d| Decodable::decode(d))?; let start_pos: BytePos = d.read_struct_field("start_pos", 2, |d| Decodable::decode(d))?; let end_pos: BytePos = d.read_struct_field("end_pos", 3, |d| Decodable::decode(d))?; let lines: Vec = d.read_struct_field("lines", 4, |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", 5, |d| Decodable::decode(d))?; Ok(FileMap { name, name_was_remapped, // `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: RefCell::new(ExternalSource::AbsentOk), lines: RefCell::new(lines), multibyte_chars: RefCell::new(multibyte_chars) }) }) } } 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, mut src: String, start_pos: BytePos) -> FileMap { remove_bom(&mut src); let mut hasher: StableHasher = StableHasher::new(); hasher.write(src.as_bytes()); let src_hash = hasher.finish(); let end_pos = start_pos.to_usize() + src.len(); FileMap { name, name_was_remapped, crate_of_origin: 0, src: Some(Rc::new(src)), src_hash, external_src: RefCell::new(ExternalSource::Unneeded), start_pos, end_pos: Pos::from_usize(end_pos), lines: RefCell::new(Vec::new()), multibyte_chars: RefCell::new(Vec::new()), } } /// 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(&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(); 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() || 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> { 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 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; let begin = 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 is_real_file(&self) -> bool { !(self.name.starts_with("<") && self.name.ends_with(">")) } 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 { 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]) } } } /// 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 { fn from_usize(n: usize) -> BytePos { BytePos(n as u32) } fn to_usize(&self) -> usize { let BytePos(n) = *self; n as usize } } impl Add for BytePos { type Output = BytePos; fn add(self, rhs: BytePos) -> BytePos { BytePos((self.to_usize() + rhs.to_usize()) as u32) } } impl Sub for BytePos { type Output = BytePos; 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 { fn from_usize(n: usize) -> CharPos { CharPos(n) } fn to_usize(&self) -> usize { let CharPos(n) = *self; n } } impl Add for CharPos { type Output = CharPos; fn add(self, rhs: CharPos) -> CharPos { CharPos(self.to_usize() + rhs.to_usize()) } } impl Sub for CharPos { type Output = CharPos; 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: Rc, /// The (1-based) line number pub line: usize, /// The (0-based) column offset pub col: CharPos } /// 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>, } // used to be structural records. Better names, anyone? #[derive(Debug)] pub struct FileMapAndLine { pub fm: Rc, pub line: usize } #[derive(Debug)] pub struct FileMapAndBytePos { pub fm: Rc, 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: Rc, 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 (if known) pub def_site_span: Option, } // _____________________________________________________________________________ // SpanLinesError, SpanSnippetError, DistinctSources, MalformedCodemapPositions // 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), MalformedForCodemap(MalformedCodemapPositions), SourceNotAvailable { filename: String } } #[derive(Clone, PartialEq, Eq, Debug)] pub struct DistinctSources { pub begin: (String, BytePos), pub end: (String, BytePos) } #[derive(Clone, PartialEq, Eq, Debug)] pub struct MalformedCodemapPositions { pub name: String, 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); } }