/
codemap.rs
512 lines (443 loc) · 15.2 KB
/
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.
/*!
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 std::cmp;
use extra::serialize::{Encodable, Decodable, Encoder, Decoder};
pub trait Pos {
fn from_uint(n: uint) -> Self;
fn to_uint(&self) -> uint;
}
/// A byte offset. Keep this small (currently 32-bits), as AST contains
/// a lot of them.
#[deriving(Clone, Eq, IterBytes, Ord)]
pub struct BytePos(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.
#[deriving(Eq,IterBytes, Ord)]
pub struct CharPos(uint);
// XXX: Lots of boilerplate in these impls, but so far my attempts to fix
// have been unsuccessful
impl Pos for BytePos {
fn from_uint(n: uint) -> BytePos { BytePos(n as u32) }
fn to_uint(&self) -> uint { **self as uint }
}
impl Add<BytePos, BytePos> for BytePos {
fn add(&self, rhs: &BytePos) -> BytePos {
BytePos(**self + **rhs)
}
}
impl Sub<BytePos, BytePos> for BytePos {
fn sub(&self, rhs: &BytePos) -> BytePos {
BytePos(**self - **rhs)
}
}
impl Pos for CharPos {
fn from_uint(n: uint) -> CharPos { CharPos(n) }
fn to_uint(&self) -> uint { **self }
}
impl Add<CharPos,CharPos> for CharPos {
fn add(&self, rhs: &CharPos) -> CharPos {
CharPos(**self + **rhs)
}
}
impl Sub<CharPos,CharPos> for CharPos {
fn sub(&self, rhs: &CharPos) -> CharPos {
CharPos(**self - **rhs)
}
}
/**
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.
*/
#[deriving(Clone, IterBytes)]
pub struct Span {
lo: BytePos,
hi: BytePos,
expn_info: Option<@ExpnInfo>
}
pub static DUMMY_SP: Span = Span { lo: BytePos(0), hi: BytePos(0), expn_info: None };
#[deriving(Clone, Eq, Encodable, Decodable, IterBytes)]
pub struct Spanned<T> {
node: T,
span: Span,
}
impl cmp::Eq for Span {
fn eq(&self, other: &Span) -> bool {
return (*self).lo == (*other).lo && (*self).hi == (*other).hi;
}
fn ne(&self, other: &Span) -> bool { !(*self).eq(other) }
}
impl<S:Encoder> Encodable<S> for Span {
/* Note #1972 -- spans are encoded but not decoded */
fn encode(&self, s: &mut S) {
s.emit_nil()
}
}
impl<D:Decoder> Decodable<D> for Span {
fn decode(_d: &mut D) -> Span {
DUMMY_SP
}
}
pub fn spanned<T>(lo: BytePos, hi: BytePos, t: T) -> Spanned<T> {
respan(mk_sp(lo, hi), t)
}
pub fn respan<T>(sp: Span, t: T) -> Spanned<T> {
Spanned {node: t, span: sp}
}
pub fn dummy_spanned<T>(t: T) -> Spanned<T> {
respan(DUMMY_SP, t)
}
/* assuming that we're not in macro expansion */
pub fn mk_sp(lo: BytePos, hi: BytePos) -> Span {
Span {lo: lo, hi: hi, expn_info: None}
}
/// A source code location used for error reporting
pub struct Loc {
/// Information about the original source
file: @FileMap,
/// The (1-based) line number
line: uint,
/// The (0-based) column offset
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.
pub struct LocWithOpt {
filename: FileName,
line: uint,
col: CharPos,
file: Option<@FileMap>,
}
// used to be structural records. Better names, anyone?
pub struct FileMapAndLine {fm: @FileMap, line: uint}
pub struct FileMapAndBytePos {fm: @FileMap, pos: BytePos}
#[deriving(IterBytes)]
pub enum MacroFormat {
// e.g. #[deriving(...)] <item>
MacroAttribute,
// e.g. `format!()`
MacroBang
}
#[deriving(IterBytes)]
pub struct NameAndSpan {
name: @str,
// the format with which the macro was invoked.
format: MacroFormat,
span: Option<Span>
}
/// Extra information for tracking macro expansion of spans
#[deriving(IterBytes)]
pub struct ExpnInfo {
call_site: Span,
callee: NameAndSpan
}
pub type FileName = @str;
pub struct FileLines
{
file: @FileMap,
lines: ~[uint]
}
// represents the origin of a file:
pub enum FileSubstr {
// indicates that this is a normal standalone file:
FssNone,
// indicates that this "file" is actually a substring
// of another file that appears earlier in the codemap
FssInternal(Span),
}
/// 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,
}
/// A single source in the CodeMap
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>`
name: FileName,
/// Extra information used by qquote
substr: FileSubstr,
/// The complete source code
src: @str,
/// The start position of this source in the CodeMap
start_pos: BytePos,
/// Locations of lines beginnings in the source code
lines: @mut ~[BytePos],
/// Locations of multi-byte characters in the source code
multibyte_chars: @mut ~[MultiByteChar],
}
impl FileMap {
// 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
pub fn next_line(&self, pos: BytePos) {
// the new charpos must be > the last one (or it's the first one).
let lines = &mut *self.lines;
assert!((lines.len() == 0) || (lines[lines.len() - 1] < pos))
lines.push(pos);
}
// get a line from the list of pre-computed line-beginnings
pub fn get_line(&self, line: int) -> ~str {
let begin: BytePos = self.lines[line] - self.start_pos;
let begin = begin.to_uint();
let slice = self.src.slice_from(begin);
match slice.find('\n') {
Some(e) => slice.slice_to(e).to_owned(),
None => slice.to_owned()
}
}
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);
}
pub fn is_real_file(&self) -> bool {
!(self.name.starts_with("<") && self.name.ends_with(">"))
}
}
pub struct CodeMap {
files: @mut ~[@FileMap]
}
impl CodeMap {
pub fn new() -> CodeMap {
CodeMap {
files: @mut ~[],
}
}
/// Add a new FileMap to the CodeMap and return it
pub fn new_filemap(&self, filename: FileName, src: @str) -> @FileMap {
return self.new_filemap_w_substr(filename, FssNone, src);
}
pub fn new_filemap_w_substr(&self,
filename: FileName,
substr: FileSubstr,
src: @str)
-> @FileMap {
let files = &mut *self.files;
let start_pos = if files.len() == 0 {
0
} else {
let last_start = files.last().start_pos.to_uint();
let last_len = files.last().src.len();
last_start + last_len
};
let filemap = @FileMap {
name: filename, substr: substr, src: src,
start_pos: Pos::from_uint(start_pos),
lines: @mut ~[],
multibyte_chars: @mut ~[],
};
files.push(filemap);
return filemap;
}
pub fn mk_substr_filename(&self, sp: Span) -> ~str {
let pos = self.lookup_char_pos(sp.lo);
return format!("<{}:{}:{}>", pos.file.name,
pos.line, pos.col.to_uint() + 1)
}
/// Lookup source information about a BytePos
pub fn lookup_char_pos(&self, pos: BytePos) -> Loc {
return self.lookup_pos(pos);
}
pub fn lookup_char_pos_adj(&self, pos: BytePos) -> LocWithOpt {
let loc = self.lookup_char_pos(pos);
match (loc.file.substr) {
FssNone =>
LocWithOpt {
filename: loc.file.name,
line: loc.line,
col: loc.col,
file: Some(loc.file)},
FssInternal(sp) =>
self.lookup_char_pos_adj(
sp.lo + (pos - loc.file.start_pos)),
}
}
pub fn adjust_span(&self, sp: Span) -> Span {
let line = self.lookup_line(sp.lo);
match (line.fm.substr) {
FssNone => sp,
FssInternal(s) => {
self.adjust_span(Span {
lo: s.lo + (sp.lo - line.fm.start_pos),
hi: s.lo + (sp.hi - line.fm.start_pos),
expn_info: sp.expn_info
})
}
}
}
pub fn span_to_str(&self, sp: Span) -> ~str {
let files = &*self.files;
if files.len() == 0 && sp == DUMMY_SP {
return ~"no-location";
}
let lo = self.lookup_char_pos_adj(sp.lo);
let hi = self.lookup_char_pos_adj(sp.hi);
return format!("{}:{}:{}: {}:{}", lo.filename,
lo.line, lo.col.to_uint() + 1, hi.line, hi.col.to_uint() + 1)
}
pub fn span_to_filename(&self, sp: Span) -> FileName {
let lo = self.lookup_char_pos(sp.lo);
lo.file.name
}
pub fn span_to_lines(&self, sp: Span) -> @FileLines {
let lo = self.lookup_char_pos(sp.lo);
let hi = self.lookup_char_pos(sp.hi);
let mut lines = ~[];
for i in range(lo.line - 1u, hi.line as uint) {
lines.push(i);
};
return @FileLines {file: lo.file, lines: lines};
}
pub fn span_to_snippet(&self, sp: Span) -> Option<~str> {
let begin = self.lookup_byte_offset(sp.lo);
let end = self.lookup_byte_offset(sp.hi);
// FIXME #8256: this used to be an assert but whatever precondition
// it's testing isn't true for all spans in the AST, so to allow the
// caller to not have to fail (and it can't catch it since the CodeMap
// isn't sendable), return None
if begin.fm.start_pos != end.fm.start_pos {
None
} else {
Some(begin.fm.src.slice( begin.pos.to_uint(), end.pos.to_uint()).to_owned())
}
}
pub fn get_filemap(&self, filename: &str) -> @FileMap {
for fm in self.files.iter() { if filename == fm.name { return *fm; } }
//XXjdm the following triggers a mismatched type bug
// (or expected function, found _|_)
fail!(); // ("asking for " + filename + " which we don't know about");
}
}
impl CodeMap {
fn lookup_filemap_idx(&self, pos: BytePos) -> uint {
let files = &*self.files;
let len = files.len();
let mut a = 0u;
let mut b = len;
while b - a > 1u {
let m = (a + b) / 2u;
if self.files[m].start_pos > pos {
b = m;
} else {
a = m;
}
}
if (a >= len) {
fail!("position {} does not resolve to a source location", pos.to_uint())
}
return a;
}
fn lookup_line(&self, pos: BytePos) -> FileMapAndLine
{
let idx = self.lookup_filemap_idx(pos);
let f = self.files[idx];
let mut a = 0u;
let lines = &*f.lines;
let mut b = lines.len();
while b - a > 1u {
let m = (a + b) / 2u;
if lines[m] > pos { b = m; } else { a = m; }
}
return FileMapAndLine {fm: f, line: a};
}
fn lookup_pos(&self, pos: BytePos) -> Loc {
let FileMapAndLine {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);
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
};
}
fn lookup_byte_offset(&self, bpos: BytePos)
-> FileMapAndBytePos {
let idx = self.lookup_filemap_idx(bpos);
let fm = self.files[idx];
let offset = bpos - fm.start_pos;
return FileMapAndBytePos {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 mbc in map.multibyte_chars.iter() {
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)
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn t1 () {
let cm = CodeMap::new();
let fm = cm.new_filemap(@"blork.rs",@"first line.\nsecond line");
fm.next_line(BytePos(0));
assert_eq!(&fm.get_line(0),&~"first line.");
// TESTING BROKEN BEHAVIOR:
fm.next_line(BytePos(10));
assert_eq!(&fm.get_line(1),&~".");
}
#[test]
#[should_fail]
fn t2 () {
let cm = CodeMap::new();
let fm = cm.new_filemap(@"blork.rs",@"first line.\nsecond line");
// TESTING *REALLY* BROKEN BEHAVIOR:
fm.next_line(BytePos(0));
fm.next_line(BytePos(10));
fm.next_line(BytePos(2));
}
}