rust/src/libsyntax/codemap.rs

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// Copyright 2012 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.
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/*!
The CodeMap tracks all the source code used within a single crate, mapping
from integer byte positions to the original source code location. Each bit of
source parsed during crate parsing (typically files, in-memory strings, or
various bits of macro expansion) cover a continuous range of bytes in the
CodeMap and are represented by FileMaps. Byte positions are stored in `spans`
and used pervasively in the compiler. They are absolute positions within the
CodeMap, which upon request can be converted to line and column information,
source code snippets, etc.
*/
use ast_util;
use core::cmp;
use core::dvec::DVec;
use core::str;
use core::to_bytes;
use core::uint;
use core::vec;
use std::serialize::{Encodable, Decodable, Encoder, Decoder};
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trait Pos {
static pure fn from_uint(n: uint) -> self;
pure fn to_uint(&self) -> uint;
}
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/// A byte offset
pub enum BytePos = uint;
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/// 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.
pub enum CharPos = uint;
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// XXX: Lots of boilerplate in these impls, but so far my attempts to fix
// have been unsuccessful
impl BytePos: Pos {
static pure fn from_uint(n: uint) -> BytePos { BytePos(n) }
pure fn to_uint(&self) -> uint { **self }
}
impl BytePos: cmp::Eq {
pure fn eq(&self, other: &BytePos) -> bool { **self == **other }
pure fn ne(&self, other: &BytePos) -> bool { !(*self).eq(other) }
}
impl BytePos: cmp::Ord {
pure fn lt(&self, other: &BytePos) -> bool { **self < **other }
pure fn le(&self, other: &BytePos) -> bool { **self <= **other }
pure fn ge(&self, other: &BytePos) -> bool { **self >= **other }
pure fn gt(&self, other: &BytePos) -> bool { **self > **other }
}
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impl BytePos: Add<BytePos, BytePos> {
pure fn add(&self, rhs: &BytePos) -> BytePos {
BytePos(**self + **rhs)
}
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}
impl BytePos: Sub<BytePos, BytePos> {
pure fn sub(&self, rhs: &BytePos) -> BytePos {
BytePos(**self - **rhs)
}
}
impl BytePos: to_bytes::IterBytes {
pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
(**self).iter_bytes(lsb0, f)
}
}
impl CharPos: Pos {
static pure fn from_uint(n: uint) -> CharPos { CharPos(n) }
pure fn to_uint(&self) -> uint { **self }
}
impl CharPos: cmp::Eq {
pure fn eq(&self, other: &CharPos) -> bool { **self == **other }
pure fn ne(&self, other: &CharPos) -> bool { !(*self).eq(other) }
}
impl CharPos: cmp::Ord {
pure fn lt(&self, other: &CharPos) -> bool { **self < **other }
pure fn le(&self, other: &CharPos) -> bool { **self <= **other }
pure fn ge(&self, other: &CharPos) -> bool { **self >= **other }
pure fn gt(&self, other: &CharPos) -> bool { **self > **other }
}
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impl CharPos: to_bytes::IterBytes {
pure fn iter_bytes(&self, +lsb0: bool, f: to_bytes::Cb) {
(**self).iter_bytes(lsb0, f)
}
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}
impl CharPos: Add<CharPos, CharPos> {
pure fn add(&self, rhs: &CharPos) -> CharPos {
CharPos(**self + **rhs)
}
}
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impl CharPos: Sub<CharPos, CharPos> {
pure fn sub(&self, rhs: &CharPos) -> CharPos {
CharPos(**self - **rhs)
}
}
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/**
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.
*/
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pub struct span {
lo: BytePos,
hi: BytePos,
expn_info: Option<@ExpnInfo>
}
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impl span : cmp::Eq {
pure fn eq(&self, other: &span) -> bool {
return (*self).lo == (*other).lo && (*self).hi == (*other).hi;
}
pure fn ne(&self, other: &span) -> bool { !(*self).eq(other) }
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}
impl<S: Encoder> span: Encodable<S> {
/* Note #1972 -- spans are encoded but not decoded */
fn encode(&self, _s: &S) { }
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}
impl<D: Decoder> span: Decodable<D> {
static fn decode(_d: &D) -> span {
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ast_util::dummy_sp()
}
}
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/// A source code location used for error reporting
pub struct Loc {
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/// Information about the original source
file: @FileMap,
/// The (1-based) line number
line: uint,
/// The (0-based) column offset
col: CharPos
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}
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/// Extra information for tracking macro expansion of spans
pub enum ExpnInfo {
ExpandedFrom({call_site: span,
callie: {name: ~str, span: Option<span>}})
}
pub type FileName = ~str;
pub struct FileLines {
file: @FileMap,
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lines: ~[uint]
}
pub enum FileSubstr {
pub FssNone,
pub FssInternal(span),
pub FssExternal({filename: ~str, line: uint, col: CharPos})
}
/// Identifies an offset of a multi-byte character in a FileMap
pub struct MultiByteChar {
/// The absolute offset of the character in the CodeMap
pos: BytePos,
/// The number of bytes, >=2
bytes: uint,
}
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/// A single source in the CodeMap
pub struct FileMap {
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/// 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>`
name: FileName,
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/// Extra information used by qquote
substr: FileSubstr,
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/// The complete source code
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src: @~str,
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/// The start position of this source in the CodeMap
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start_pos: BytePos,
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/// Locations of lines beginnings in the source code
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mut lines: ~[BytePos],
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/// Locations of multi-byte characters in the source code
multibyte_chars: DVec<MultiByteChar>
}
pub impl FileMap {
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fn next_line(&self, +pos: BytePos) {
self.lines.push(pos);
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}
pub fn get_line(&self, line: int) -> ~str unsafe {
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let begin: BytePos = self.lines[line] - self.start_pos;
let begin = begin.to_uint();
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let end = match str::find_char_from(*self.src, '\n', begin) {
Some(e) => e,
None => str::len(*self.src)
};
str::slice(*self.src, begin, end)
}
pub fn record_multibyte_char(&self, pos: BytePos, bytes: uint) {
assert bytes >=2 && bytes <= 4;
let mbc = MultiByteChar {
pos: pos,
bytes: bytes,
};
self.multibyte_chars.push(mbc);
}
}
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pub struct CodeMap {
files: DVec<@FileMap>
}
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pub impl CodeMap {
static pub fn new() -> CodeMap {
CodeMap {
files: DVec()
}
}
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/// Add a new FileMap to the CodeMap and return it
fn new_filemap(+filename: FileName, src: @~str) -> @FileMap {
return self.new_filemap_w_substr(filename, FssNone, src);
}
fn new_filemap_w_substr(+filename: FileName, +substr: FileSubstr,
src: @~str) -> @FileMap {
let start_pos = if self.files.len() == 0 {
0
} else {
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let last_start = self.files.last().start_pos.to_uint();
let last_len = self.files.last().src.len();
last_start + last_len
};
let filemap = @FileMap {
name: filename, substr: substr, src: src,
start_pos: BytePos(start_pos),
mut lines: ~[],
multibyte_chars: DVec()
};
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self.files.push(filemap);
return filemap;
}
pub fn mk_substr_filename(&self, sp: span) -> ~str {
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let pos = self.lookup_char_pos(sp.lo);
return fmt!("<%s:%u:%u>", pos.file.name,
pos.line, pos.col.to_uint());
}
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/// Lookup source information about a BytePos
pub fn lookup_char_pos(&self, +pos: BytePos) -> Loc {
return self.lookup_pos(pos);
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}
pub fn lookup_char_pos_adj(&self, +pos: BytePos)
-> {filename: ~str, line: uint, col: CharPos, file: Option<@FileMap>}
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{
let loc = self.lookup_char_pos(pos);
match (loc.file.substr) {
FssNone => {
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{filename: /* FIXME (#2543) */ copy loc.file.name,
line: loc.line,
col: loc.col,
file: Some(loc.file)}
}
FssInternal(sp) => {
self.lookup_char_pos_adj(
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sp.lo + (pos - loc.file.start_pos))
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}
FssExternal(ref eloc) => {
{filename: /* FIXME (#2543) */ copy (*eloc).filename,
line: (*eloc).line + loc.line - 1u,
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col: if loc.line == 1 {eloc.col + loc.col} else {loc.col},
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file: None}
}
}
}
pub fn adjust_span(&self, sp: span) -> span {
let line = self.lookup_line(sp.lo);
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match (line.fm.substr) {
FssNone => sp,
FssInternal(s) => {
self.adjust_span(span {
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lo: s.lo + (sp.lo - line.fm.start_pos),
hi: s.lo + (sp.hi - line.fm.start_pos),
expn_info: sp.expn_info
})
}
FssExternal(_) => sp
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}
}
pub fn span_to_str(&self, sp: span) -> ~str {
if self.files.len() == 0 && sp == ast_util::dummy_sp() {
return ~"no-location";
}
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let lo = self.lookup_char_pos_adj(sp.lo);
let hi = self.lookup_char_pos_adj(sp.hi);
return fmt!("%s:%u:%u: %u:%u", lo.filename,
lo.line, lo.col.to_uint(), hi.line, hi.col.to_uint())
}
pub fn span_to_filename(&self, sp: span) -> FileName {
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let lo = self.lookup_char_pos(sp.lo);
return /* FIXME (#2543) */ copy lo.file.name;
}
pub fn span_to_lines(&self, sp: span) -> @FileLines {
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let lo = self.lookup_char_pos(sp.lo);
let hi = self.lookup_char_pos(sp.hi);
let mut lines = ~[];
for uint::range(lo.line - 1u, hi.line as uint) |i| {
lines.push(i);
};
return @FileLines {file: lo.file, lines: lines};
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}
pub fn span_to_snippet(&self, sp: span) -> ~str {
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let begin = self.lookup_byte_offset(sp.lo);
let end = self.lookup_byte_offset(sp.hi);
assert begin.fm.start_pos == end.fm.start_pos;
return str::slice(*begin.fm.src,
begin.pos.to_uint(), end.pos.to_uint());
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}
pub fn get_filemap(&self, filename: ~str) -> @FileMap {
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for self.files.each |fm| { if fm.name == filename { return *fm; } }
//XXjdm the following triggers a mismatched type bug
// (or expected function, found _|_)
fail; // ("asking for " + filename + " which we don't know about");
}
}
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priv impl CodeMap {
fn lookup_filemap_idx(&self, +pos: BytePos) -> uint {
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let len = self.files.len();
let mut a = 0u;
let mut b = len;
while b - a > 1u {
let m = (a + b) / 2u;
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if self.files[m].start_pos > pos {
b = m;
} else {
a = m;
}
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}
if (a >= len) {
fail fmt!("position %u does not resolve to a source location",
pos.to_uint())
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}
return a;
}
fn lookup_line(&self, +pos: BytePos)
-> {fm: @FileMap, line: uint}
{
let idx = self.lookup_filemap_idx(pos);
let f = self.files[idx];
let mut a = 0u;
let mut b = vec::len(f.lines);
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while b - a > 1u {
let m = (a + b) / 2u;
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if f.lines[m] > pos { b = m; } else { a = m; }
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}
return {fm: f, line: a};
}
fn lookup_pos(&self, +pos: BytePos) -> Loc {
let {fm: f, line: a} = self.lookup_line(pos);
let line = a + 1u; // Line numbers start at 1
let chpos = self.bytepos_to_local_charpos(pos);
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let linebpos = f.lines[a];
let linechpos = self.bytepos_to_local_charpos(linebpos);
debug!("codemap: byte pos %? is on the line at byte pos %?",
pos, linebpos);
debug!("codemap: char pos %? is on the line at char pos %?",
chpos, linechpos);
debug!("codemap: byte is on line: %?", line);
assert chpos >= linechpos;
return Loc {
file: f,
line: line,
col: chpos - linechpos
};
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}
fn span_to_str_no_adj(&self, sp: span) -> ~str {
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let lo = self.lookup_char_pos(sp.lo);
let hi = self.lookup_char_pos(sp.hi);
return fmt!("%s:%u:%u: %u:%u", lo.file.name,
lo.line, lo.col.to_uint(), hi.line, hi.col.to_uint())
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}
fn lookup_byte_offset(&self, +bpos: BytePos)
-> {fm: @FileMap, pos: BytePos} {
let idx = self.lookup_filemap_idx(bpos);
let fm = self.files[idx];
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let offset = bpos - fm.start_pos;
return {fm: fm, pos: offset};
}
// Converts an absolute BytePos to a CharPos relative to the file it is
// located in
fn bytepos_to_local_charpos(&self, +bpos: BytePos) -> CharPos {
debug!("codemap: converting %? to char pos", bpos);
let idx = self.lookup_filemap_idx(bpos);
let map = self.files[idx];
// The number of extra bytes due to multibyte chars in the FileMap
let mut total_extra_bytes = 0;
for map.multibyte_chars.each |mbc| {
debug!("codemap: %?-byte char at %?", mbc.bytes, mbc.pos);
if mbc.pos < bpos {
total_extra_bytes += mbc.bytes;
// We should never see a byte position in the middle of a
// character
assert bpos == mbc.pos
|| bpos.to_uint() >= mbc.pos.to_uint() + mbc.bytes;
} else {
break;
}
}
CharPos(bpos.to_uint() - total_extra_bytes)
}
}
//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//