rust/src/libsyntax/diagnostic.rs
Alex Crichton 1860ee521a std: Implement CString-related RFCs
This commit is an implementation of [RFC 592][r592] and [RFC 840][r840]. These
two RFCs tweak the behavior of `CString` and add a new `CStr` unsized slice type
to the module.

[r592]: https://github.com/rust-lang/rfcs/blob/master/text/0592-c-str-deref.md
[r840]: https://github.com/rust-lang/rfcs/blob/master/text/0840-no-panic-in-c-string.md

The new `CStr` type is only constructable via two methods:

1. By `deref`'ing from a `CString`
2. Unsafely via `CStr::from_ptr`

The purpose of `CStr` is to be an unsized type which is a thin pointer to a
`libc::c_char` (currently it is a fat pointer slice due to implementation
limitations). Strings from C can be safely represented with a `CStr` and an
appropriate lifetime as well. Consumers of `&CString` should now consume `&CStr`
instead to allow producers to pass in C-originating strings instead of just
Rust-allocated strings.

A new constructor was added to `CString`, `new`, which takes `T: IntoBytes`
instead of separate `from_slice` and `from_vec` methods (both have been
deprecated in favor of `new`). The `new` method returns a `Result` instead of
panicking.  The error variant contains the relevant information about where the
error happened and bytes (if present). Conversions are provided to the
`io::Error` and `old_io::IoError` types via the `FromError` trait which
translate to `InvalidInput`.

This is a breaking change due to the modification of existing `#[unstable]` APIs
and new deprecation, and more detailed information can be found in the two RFCs.
Notable breakage includes:

* All construction of `CString` now needs to use `new` and handle the outgoing
  `Result`.
* Usage of `CString` as a byte slice now explicitly needs a `.as_bytes()` call.
* The `as_slice*` methods have been removed in favor of just having the
  `as_bytes*` methods.

Closes #22469
Closes #22470
[breaking-change]
2015-02-18 14:15:43 -08:00

652 lines
22 KiB
Rust

// 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.
pub use self::Level::*;
pub use self::RenderSpan::*;
pub use self::ColorConfig::*;
use self::Destination::*;
use codemap::{COMMAND_LINE_SP, COMMAND_LINE_EXPN, Pos, Span};
use codemap;
use diagnostics;
use std::cell::{RefCell, Cell};
use std::fmt;
use std::old_io;
use std::string::String;
use term::WriterWrapper;
use term;
/// maximum number of lines we will print for each error; arbitrary.
static MAX_LINES: usize = 6;
#[derive(Clone, Copy)]
pub enum RenderSpan {
/// A FullSpan renders with both with an initial line for the
/// message, prefixed by file:linenum, followed by a summary of
/// the source code covered by the span.
FullSpan(Span),
/// A FileLine renders with just a line for the message prefixed
/// by file:linenum.
FileLine(Span),
}
impl RenderSpan {
fn span(self) -> Span {
match self {
FullSpan(s) | FileLine(s) => s
}
}
fn is_full_span(&self) -> bool {
match self {
&FullSpan(..) => true,
&FileLine(..) => false,
}
}
}
#[derive(Clone, Copy)]
pub enum ColorConfig {
Auto,
Always,
Never
}
pub trait Emitter {
fn emit(&mut self, cmsp: Option<(&codemap::CodeMap, Span)>,
msg: &str, code: Option<&str>, lvl: Level);
fn custom_emit(&mut self, cm: &codemap::CodeMap,
sp: RenderSpan, msg: &str, lvl: Level);
}
/// This structure is used to signify that a task has panicked with a fatal error
/// from the diagnostics. You can use this with the `Any` trait to figure out
/// how a rustc task died (if so desired).
#[derive(Copy)]
pub struct FatalError;
/// Signifies that the compiler died with an explicit call to `.bug`
/// or `.span_bug` rather than a failed assertion, etc.
#[derive(Copy)]
pub struct ExplicitBug;
/// A span-handler is like a handler but also
/// accepts span information for source-location
/// reporting.
pub struct SpanHandler {
pub handler: Handler,
pub cm: codemap::CodeMap,
}
impl SpanHandler {
pub fn span_fatal(&self, sp: Span, msg: &str) -> ! {
self.handler.emit(Some((&self.cm, sp)), msg, Fatal);
panic!(FatalError);
}
pub fn span_fatal_with_code(&self, sp: Span, msg: &str, code: &str) -> ! {
self.handler.emit_with_code(Some((&self.cm, sp)), msg, code, Fatal);
panic!(FatalError);
}
pub fn span_err(&self, sp: Span, msg: &str) {
self.handler.emit(Some((&self.cm, sp)), msg, Error);
self.handler.bump_err_count();
}
pub fn span_err_with_code(&self, sp: Span, msg: &str, code: &str) {
self.handler.emit_with_code(Some((&self.cm, sp)), msg, code, Error);
self.handler.bump_err_count();
}
pub fn span_warn(&self, sp: Span, msg: &str) {
self.handler.emit(Some((&self.cm, sp)), msg, Warning);
}
pub fn span_warn_with_code(&self, sp: Span, msg: &str, code: &str) {
self.handler.emit_with_code(Some((&self.cm, sp)), msg, code, Warning);
}
pub fn span_note(&self, sp: Span, msg: &str) {
self.handler.emit(Some((&self.cm, sp)), msg, Note);
}
pub fn span_end_note(&self, sp: Span, msg: &str) {
self.handler.custom_emit(&self.cm, FullSpan(sp), msg, Note);
}
pub fn span_help(&self, sp: Span, msg: &str) {
self.handler.emit(Some((&self.cm, sp)), msg, Help);
}
pub fn fileline_note(&self, sp: Span, msg: &str) {
self.handler.custom_emit(&self.cm, FileLine(sp), msg, Note);
}
pub fn fileline_help(&self, sp: Span, msg: &str) {
self.handler.custom_emit(&self.cm, FileLine(sp), msg, Help);
}
pub fn span_bug(&self, sp: Span, msg: &str) -> ! {
self.handler.emit(Some((&self.cm, sp)), msg, Bug);
panic!(ExplicitBug);
}
pub fn span_unimpl(&self, sp: Span, msg: &str) -> ! {
self.span_bug(sp, &format!("unimplemented {}", msg)[]);
}
pub fn handler<'a>(&'a self) -> &'a Handler {
&self.handler
}
}
/// A handler deals with errors; certain errors
/// (fatal, bug, unimpl) may cause immediate exit,
/// others log errors for later reporting.
pub struct Handler {
err_count: Cell<usize>,
emit: RefCell<Box<Emitter + Send>>,
pub can_emit_warnings: bool
}
impl Handler {
pub fn fatal(&self, msg: &str) -> ! {
self.emit.borrow_mut().emit(None, msg, None, Fatal);
panic!(FatalError);
}
pub fn err(&self, msg: &str) {
self.emit.borrow_mut().emit(None, msg, None, Error);
self.bump_err_count();
}
pub fn bump_err_count(&self) {
self.err_count.set(self.err_count.get() + 1);
}
pub fn err_count(&self) -> usize {
self.err_count.get()
}
pub fn has_errors(&self) -> bool {
self.err_count.get() > 0
}
pub fn abort_if_errors(&self) {
let s;
match self.err_count.get() {
0 => return,
1 => s = "aborting due to previous error".to_string(),
_ => {
s = format!("aborting due to {} previous errors",
self.err_count.get());
}
}
self.fatal(&s[]);
}
pub fn warn(&self, msg: &str) {
self.emit.borrow_mut().emit(None, msg, None, Warning);
}
pub fn note(&self, msg: &str) {
self.emit.borrow_mut().emit(None, msg, None, Note);
}
pub fn help(&self, msg: &str) {
self.emit.borrow_mut().emit(None, msg, None, Help);
}
pub fn bug(&self, msg: &str) -> ! {
self.emit.borrow_mut().emit(None, msg, None, Bug);
panic!(ExplicitBug);
}
pub fn unimpl(&self, msg: &str) -> ! {
self.bug(&format!("unimplemented {}", msg)[]);
}
pub fn emit(&self,
cmsp: Option<(&codemap::CodeMap, Span)>,
msg: &str,
lvl: Level) {
if lvl == Warning && !self.can_emit_warnings { return }
self.emit.borrow_mut().emit(cmsp, msg, None, lvl);
}
pub fn emit_with_code(&self,
cmsp: Option<(&codemap::CodeMap, Span)>,
msg: &str,
code: &str,
lvl: Level) {
if lvl == Warning && !self.can_emit_warnings { return }
self.emit.borrow_mut().emit(cmsp, msg, Some(code), lvl);
}
pub fn custom_emit(&self, cm: &codemap::CodeMap,
sp: RenderSpan, msg: &str, lvl: Level) {
if lvl == Warning && !self.can_emit_warnings { return }
self.emit.borrow_mut().custom_emit(cm, sp, msg, lvl);
}
}
pub fn mk_span_handler(handler: Handler, cm: codemap::CodeMap) -> SpanHandler {
SpanHandler {
handler: handler,
cm: cm,
}
}
pub fn default_handler(color_config: ColorConfig,
registry: Option<diagnostics::registry::Registry>,
can_emit_warnings: bool) -> Handler {
mk_handler(can_emit_warnings, box EmitterWriter::stderr(color_config, registry))
}
pub fn mk_handler(can_emit_warnings: bool, e: Box<Emitter + Send>) -> Handler {
Handler {
err_count: Cell::new(0),
emit: RefCell::new(e),
can_emit_warnings: can_emit_warnings
}
}
#[derive(Copy, PartialEq, Clone, Debug)]
pub enum Level {
Bug,
Fatal,
Error,
Warning,
Note,
Help,
}
impl fmt::Display for Level {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
use std::fmt::Display;
match *self {
Bug => "error: internal compiler error".fmt(f),
Fatal | Error => "error".fmt(f),
Warning => "warning".fmt(f),
Note => "note".fmt(f),
Help => "help".fmt(f),
}
}
}
impl Level {
fn color(self) -> term::color::Color {
match self {
Bug | Fatal | Error => term::color::BRIGHT_RED,
Warning => term::color::BRIGHT_YELLOW,
Note => term::color::BRIGHT_GREEN,
Help => term::color::BRIGHT_CYAN,
}
}
}
fn print_maybe_styled(w: &mut EmitterWriter,
msg: &str,
color: term::attr::Attr) -> old_io::IoResult<()> {
match w.dst {
Terminal(ref mut t) => {
try!(t.attr(color));
// If `msg` ends in a newline, we need to reset the color before
// the newline. We're making the assumption that we end up writing
// to a `LineBufferedWriter`, which means that emitting the reset
// after the newline ends up buffering the reset until we print
// another line or exit. Buffering the reset is a problem if we're
// sharing the terminal with any other programs (e.g. other rustc
// instances via `make -jN`).
//
// Note that if `msg` contains any internal newlines, this will
// result in the `LineBufferedWriter` flushing twice instead of
// once, which still leaves the opportunity for interleaved output
// to be miscolored. We assume this is rare enough that we don't
// have to worry about it.
if msg.ends_with("\n") {
try!(t.write_str(&msg[..msg.len()-1]));
try!(t.reset());
try!(t.write_str("\n"));
} else {
try!(t.write_str(msg));
try!(t.reset());
}
Ok(())
}
Raw(ref mut w) => {
w.write_str(msg)
}
}
}
fn print_diagnostic(dst: &mut EmitterWriter, topic: &str, lvl: Level,
msg: &str, code: Option<&str>) -> old_io::IoResult<()> {
if !topic.is_empty() {
try!(write!(&mut dst.dst, "{} ", topic));
}
try!(print_maybe_styled(dst,
&format!("{}: ", lvl.to_string())[],
term::attr::ForegroundColor(lvl.color())));
try!(print_maybe_styled(dst,
&format!("{}", msg)[],
term::attr::Bold));
match code {
Some(code) => {
let style = term::attr::ForegroundColor(term::color::BRIGHT_MAGENTA);
try!(print_maybe_styled(dst, &format!(" [{}]", code.clone())[], style));
}
None => ()
}
try!(dst.dst.write_char('\n'));
Ok(())
}
pub struct EmitterWriter {
dst: Destination,
registry: Option<diagnostics::registry::Registry>
}
enum Destination {
Terminal(Box<term::Terminal<WriterWrapper> + Send>),
Raw(Box<Writer + Send>),
}
impl EmitterWriter {
pub fn stderr(color_config: ColorConfig,
registry: Option<diagnostics::registry::Registry>) -> EmitterWriter {
let stderr = old_io::stderr();
let use_color = match color_config {
Always => true,
Never => false,
Auto => stderr.get_ref().isatty()
};
if use_color {
let dst = match term::stderr() {
Some(t) => Terminal(t),
None => Raw(box stderr),
};
EmitterWriter { dst: dst, registry: registry }
} else {
EmitterWriter { dst: Raw(box stderr), registry: registry }
}
}
pub fn new(dst: Box<Writer + Send>,
registry: Option<diagnostics::registry::Registry>) -> EmitterWriter {
EmitterWriter { dst: Raw(dst), registry: registry }
}
}
impl Writer for Destination {
fn write_all(&mut self, bytes: &[u8]) -> old_io::IoResult<()> {
match *self {
Terminal(ref mut t) => t.write_all(bytes),
Raw(ref mut w) => w.write_all(bytes),
}
}
}
impl Emitter for EmitterWriter {
fn emit(&mut self,
cmsp: Option<(&codemap::CodeMap, Span)>,
msg: &str, code: Option<&str>, lvl: Level) {
let error = match cmsp {
Some((cm, COMMAND_LINE_SP)) => emit(self, cm,
FileLine(COMMAND_LINE_SP),
msg, code, lvl, false),
Some((cm, sp)) => emit(self, cm, FullSpan(sp), msg, code, lvl, false),
None => print_diagnostic(self, "", lvl, msg, code),
};
match error {
Ok(()) => {}
Err(e) => panic!("failed to print diagnostics: {:?}", e),
}
}
fn custom_emit(&mut self, cm: &codemap::CodeMap,
sp: RenderSpan, msg: &str, lvl: Level) {
match emit(self, cm, sp, msg, None, lvl, true) {
Ok(()) => {}
Err(e) => panic!("failed to print diagnostics: {:?}", e),
}
}
}
fn emit(dst: &mut EmitterWriter, cm: &codemap::CodeMap, rsp: RenderSpan,
msg: &str, code: Option<&str>, lvl: Level, custom: bool) -> old_io::IoResult<()> {
let sp = rsp.span();
// We cannot check equality directly with COMMAND_LINE_SP
// since PartialEq is manually implemented to ignore the ExpnId
let ss = if sp.expn_id == COMMAND_LINE_EXPN {
"<command line option>".to_string()
} else {
cm.span_to_string(sp)
};
if custom {
// we want to tell compiletest/runtest to look at the last line of the
// span (since `custom_highlight_lines` displays an arrow to the end of
// the span)
let span_end = Span { lo: sp.hi, hi: sp.hi, expn_id: sp.expn_id};
let ses = cm.span_to_string(span_end);
try!(print_diagnostic(dst, &ses[], lvl, msg, code));
if rsp.is_full_span() {
try!(custom_highlight_lines(dst, cm, sp, lvl, cm.span_to_lines(sp)));
}
} else {
try!(print_diagnostic(dst, &ss[], lvl, msg, code));
if rsp.is_full_span() {
try!(highlight_lines(dst, cm, sp, lvl, cm.span_to_lines(sp)));
}
}
if sp != COMMAND_LINE_SP {
try!(print_macro_backtrace(dst, cm, sp));
}
match code {
Some(code) =>
match dst.registry.as_ref().and_then(|registry| registry.find_description(code)) {
Some(_) => {
try!(print_diagnostic(dst, &ss[], Help,
&format!("pass `--explain {}` to see a detailed \
explanation", code)[], None));
}
None => ()
},
None => (),
}
Ok(())
}
fn highlight_lines(err: &mut EmitterWriter,
cm: &codemap::CodeMap,
sp: Span,
lvl: Level,
lines: codemap::FileLines) -> old_io::IoResult<()> {
let fm = &*lines.file;
let mut elided = false;
let mut display_lines = &lines.lines[];
if display_lines.len() > MAX_LINES {
display_lines = &display_lines[0..MAX_LINES];
elided = true;
}
// Print the offending lines
for &line_number in display_lines {
if let Some(line) = fm.get_line(line_number) {
try!(write!(&mut err.dst, "{}:{} {}\n", fm.name,
line_number + 1, line));
}
}
if elided {
let last_line = display_lines[display_lines.len() - 1];
let s = format!("{}:{} ", fm.name, last_line + 1);
try!(write!(&mut err.dst, "{0:1$}...\n", "", s.len()));
}
// FIXME (#3260)
// If there's one line at fault we can easily point to the problem
if lines.lines.len() == 1 {
let lo = cm.lookup_char_pos(sp.lo);
let mut digits = 0;
let mut num = (lines.lines[0] + 1) / 10;
// how many digits must be indent past?
while num > 0 { num /= 10; digits += 1; }
let mut s = String::new();
// Skip is the number of characters we need to skip because they are
// part of the 'filename:line ' part of the previous line.
let skip = fm.name.width(false) + digits + 3;
for _ in 0..skip {
s.push(' ');
}
if let Some(orig) = fm.get_line(lines.lines[0]) {
let mut col = skip;
let mut lastc = ' ';
let mut iter = orig.chars().enumerate();
for (pos, ch) in iter.by_ref() {
lastc = ch;
if pos >= lo.col.to_usize() { break; }
// Whenever a tab occurs on the previous line, we insert one on
// the error-point-squiggly-line as well (instead of a space).
// That way the squiggly line will usually appear in the correct
// position.
match ch {
'\t' => {
col += 8 - col%8;
s.push('\t');
},
c => for _ in 0..c.width(false).unwrap_or(0) {
col += 1;
s.push(' ');
},
}
}
try!(write!(&mut err.dst, "{}", s));
let mut s = String::from_str("^");
let count = match lastc {
// Most terminals have a tab stop every eight columns by default
'\t' => 8 - col%8,
_ => lastc.width(false).unwrap_or(0),
};
col += count;
s.extend(::std::iter::repeat('~').take(count));
let hi = cm.lookup_char_pos(sp.hi);
if hi.col != lo.col {
for (pos, ch) in iter {
if pos >= hi.col.to_usize() { break; }
let count = match ch {
'\t' => 8 - col%8,
_ => ch.width(false).unwrap_or(0),
};
col += count;
s.extend(::std::iter::repeat('~').take(count));
}
}
if s.len() > 1 {
// One extra squiggly is replaced by a "^"
s.pop();
}
try!(print_maybe_styled(err,
&format!("{}\n", s)[],
term::attr::ForegroundColor(lvl.color())));
}
}
Ok(())
}
/// Here are the differences between this and the normal `highlight_lines`:
/// `custom_highlight_lines` will always put arrow on the last byte of the
/// span (instead of the first byte). Also, when the span is too long (more
/// than 6 lines), `custom_highlight_lines` will print the first line, then
/// dot dot dot, then last line, whereas `highlight_lines` prints the first
/// six lines.
fn custom_highlight_lines(w: &mut EmitterWriter,
cm: &codemap::CodeMap,
sp: Span,
lvl: Level,
lines: codemap::FileLines)
-> old_io::IoResult<()> {
let fm = &*lines.file;
let lines = &lines.lines[];
if lines.len() > MAX_LINES {
if let Some(line) = fm.get_line(lines[0]) {
try!(write!(&mut w.dst, "{}:{} {}\n", fm.name,
lines[0] + 1, line));
}
try!(write!(&mut w.dst, "...\n"));
let last_line_number = lines[lines.len() - 1];
if let Some(last_line) = fm.get_line(last_line_number) {
try!(write!(&mut w.dst, "{}:{} {}\n", fm.name,
last_line_number + 1, last_line));
}
} else {
for &line_number in lines {
if let Some(line) = fm.get_line(line_number) {
try!(write!(&mut w.dst, "{}:{} {}\n", fm.name,
line_number + 1, line));
}
}
}
let last_line_start = format!("{}:{} ", fm.name, lines[lines.len()-1]+1);
let hi = cm.lookup_char_pos(sp.hi);
let skip = last_line_start.width(false);
let mut s = String::new();
for _ in 0..skip {
s.push(' ');
}
if let Some(orig) = fm.get_line(lines[0]) {
let iter = orig.chars().enumerate();
for (pos, ch) in iter {
// Span seems to use half-opened interval, so subtract 1
if pos >= hi.col.to_usize() - 1 { break; }
// Whenever a tab occurs on the previous line, we insert one on
// the error-point-squiggly-line as well (instead of a space).
// That way the squiggly line will usually appear in the correct
// position.
match ch {
'\t' => s.push('\t'),
c => for _ in 0..c.width(false).unwrap_or(0) {
s.push(' ');
},
}
}
}
s.push('^');
s.push('\n');
print_maybe_styled(w,
&s[],
term::attr::ForegroundColor(lvl.color()))
}
fn print_macro_backtrace(w: &mut EmitterWriter,
cm: &codemap::CodeMap,
sp: Span)
-> old_io::IoResult<()> {
let cs = try!(cm.with_expn_info(sp.expn_id, |expn_info| -> old_io::IoResult<_> {
match expn_info {
Some(ei) => {
let ss = ei.callee.span.map_or(String::new(),
|span| cm.span_to_string(span));
let (pre, post) = match ei.callee.format {
codemap::MacroAttribute => ("#[", "]"),
codemap::MacroBang => ("", "!")
};
try!(print_diagnostic(w, &ss[], Note,
&format!("in expansion of {}{}{}", pre,
ei.callee.name,
post)[], None));
let ss = cm.span_to_string(ei.call_site);
try!(print_diagnostic(w, &ss[], Note, "expansion site", None));
Ok(Some(ei.call_site))
}
None => Ok(None)
}
}));
cs.map_or(Ok(()), |call_site| print_macro_backtrace(w, cm, call_site))
}
pub fn expect<T, M>(diag: &SpanHandler, opt: Option<T>, msg: M) -> T where
M: FnOnce() -> String,
{
match opt {
Some(t) => t,
None => diag.handler().bug(&msg()[]),
}
}