rust/src/librustc_errors/emitter.rs

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// Copyright 2012-2015 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.
use self::Destination::*;
use syntax_pos::{COMMAND_LINE_SP, DUMMY_SP, FileMap, Span, MultiSpan, CharPos};
use {Level, CodeSuggestion, DiagnosticBuilder, CodeMapper};
use RenderSpan::*;
use snippet::{StyledString, Style, Annotation, Line};
use styled_buffer::StyledBuffer;
use std::io::prelude::*;
use std::io;
use std::rc::Rc;
use term;
/// Emitter trait for emitting errors.
pub trait Emitter {
/// Emit a structured diagnostic.
fn emit(&mut self, db: &DiagnosticBuilder);
}
impl Emitter for EmitterWriter {
fn emit(&mut self, db: &DiagnosticBuilder) {
self.emit_messages_default(db);
}
}
/// maximum number of lines we will print for each error; arbitrary.
pub const MAX_HIGHLIGHT_LINES: usize = 6;
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum ColorConfig {
Auto,
Always,
Never,
}
impl ColorConfig {
fn use_color(&self) -> bool {
match *self {
ColorConfig::Always => true,
ColorConfig::Never => false,
ColorConfig::Auto => stderr_isatty(),
}
}
}
pub struct EmitterWriter {
dst: Destination,
cm: Option<Rc<CodeMapper>>,
}
struct FileWithAnnotatedLines {
file: Rc<FileMap>,
lines: Vec<Line>,
}
/// Do not use this for messages that end in `\n` use `println_maybe_styled` instead. See
/// `EmitterWriter::print_maybe_styled` for details.
macro_rules! print_maybe_styled {
($dst: expr, $style: expr, $($arg: tt)*) => {
$dst.print_maybe_styled(format_args!($($arg)*), $style, false)
}
}
macro_rules! println_maybe_styled {
($dst: expr, $style: expr, $($arg: tt)*) => {
$dst.print_maybe_styled(format_args!($($arg)*), $style, true)
}
}
impl EmitterWriter {
pub fn stderr(color_config: ColorConfig,
code_map: Option<Rc<CodeMapper>>)
-> EmitterWriter {
if color_config.use_color() {
let dst = Destination::from_stderr();
EmitterWriter { dst: dst,
cm: code_map}
} else {
EmitterWriter { dst: Raw(Box::new(io::stderr())),
cm: code_map}
}
}
pub fn new(dst: Box<Write + Send>,
code_map: Option<Rc<CodeMapper>>)
-> EmitterWriter {
EmitterWriter { dst: Raw(dst),
cm: code_map}
}
fn preprocess_annotations(&self, msp: &MultiSpan) -> Vec<FileWithAnnotatedLines> {
fn add_annotation_to_file(file_vec: &mut Vec<FileWithAnnotatedLines>,
file: Rc<FileMap>,
line_index: usize,
ann: Annotation) {
for slot in file_vec.iter_mut() {
// Look through each of our files for the one we're adding to
if slot.file.name == file.name {
// See if we already have a line for it
for line_slot in &mut slot.lines {
if line_slot.line_index == line_index {
line_slot.annotations.push(ann);
return;
}
}
// We don't have a line yet, create one
slot.lines.push(Line {
line_index: line_index,
annotations: vec![ann],
});
slot.lines.sort();
return;
}
}
// This is the first time we're seeing the file
file_vec.push(FileWithAnnotatedLines {
file: file,
lines: vec![Line {
line_index: line_index,
annotations: vec![ann],
}],
});
}
let mut output = vec![];
if let Some(ref cm) = self.cm {
for span_label in msp.span_labels() {
if span_label.span == DUMMY_SP || span_label.span == COMMAND_LINE_SP {
continue;
}
let lo = cm.lookup_char_pos(span_label.span.lo);
let mut hi = cm.lookup_char_pos(span_label.span.hi);
let mut is_minimized = false;
// If the span is multi-line, simplify down to the span of one character
if lo.line != hi.line {
hi.line = lo.line;
hi.col = CharPos(lo.col.0 + 1);
is_minimized = true;
}
// Watch out for "empty spans". If we get a span like 6..6, we
// want to just display a `^` at 6, so convert that to
// 6..7. This is degenerate input, but it's best to degrade
// gracefully -- and the parser likes to supply a span like
// that for EOF, in particular.
if lo.col == hi.col {
hi.col = CharPos(lo.col.0 + 1);
}
add_annotation_to_file(&mut output,
lo.file,
lo.line,
Annotation {
start_col: lo.col.0,
end_col: hi.col.0,
is_primary: span_label.is_primary,
is_minimized: is_minimized,
label: span_label.label.clone(),
});
}
}
output
}
fn render_source_line(&self,
buffer: &mut StyledBuffer,
file: Rc<FileMap>,
line: &Line,
width_offset: usize) {
let source_string = file.get_line(line.line_index - 1)
.unwrap_or("");
let line_offset = buffer.num_lines();
// First create the source line we will highlight.
buffer.puts(line_offset, width_offset, &source_string, Style::Quotation);
buffer.puts(line_offset,
0,
&(line.line_index.to_string()),
Style::LineNumber);
draw_col_separator(buffer, line_offset, width_offset - 2);
if line.annotations.is_empty() {
return;
}
// We want to display like this:
//
// vec.push(vec.pop().unwrap());
// --- ^^^ _ previous borrow ends here
// | |
// | error occurs here
// previous borrow of `vec` occurs here
//
// But there are some weird edge cases to be aware of:
//
// vec.push(vec.pop().unwrap());
// -------- - previous borrow ends here
// ||
// |this makes no sense
// previous borrow of `vec` occurs here
//
// For this reason, we group the lines into "highlight lines"
// and "annotations lines", where the highlight lines have the `~`.
// Sort the annotations by (start, end col)
let mut annotations = line.annotations.clone();
annotations.sort();
// Next, create the highlight line.
for annotation in &annotations {
for p in annotation.start_col..annotation.end_col {
if annotation.is_primary {
buffer.putc(line_offset + 1,
width_offset + p,
'^',
Style::UnderlinePrimary);
if !annotation.is_minimized {
buffer.set_style(line_offset,
width_offset + p,
Style::UnderlinePrimary);
}
} else {
buffer.putc(line_offset + 1,
width_offset + p,
'-',
Style::UnderlineSecondary);
if !annotation.is_minimized {
buffer.set_style(line_offset,
width_offset + p,
Style::UnderlineSecondary);
}
}
}
}
draw_col_separator(buffer, line_offset + 1, width_offset - 2);
// Now we are going to write labels in. To start, we'll exclude
// the annotations with no labels.
let (labeled_annotations, unlabeled_annotations): (Vec<_>, _) = annotations.into_iter()
.partition(|a| a.label.is_some());
// If there are no annotations that need text, we're done.
if labeled_annotations.is_empty() {
return;
}
// Now add the text labels. We try, when possible, to stick the rightmost
// annotation at the end of the highlight line:
//
// vec.push(vec.pop().unwrap());
// --- --- - previous borrow ends here
//
// But sometimes that's not possible because one of the other
// annotations overlaps it. For example, from the test
// `span_overlap_label`, we have the following annotations
// (written on distinct lines for clarity):
//
// fn foo(x: u32) {
// --------------
// -
//
// In this case, we can't stick the rightmost-most label on
// the highlight line, or we would get:
//
// fn foo(x: u32) {
// -------- x_span
// |
// fn_span
//
// which is totally weird. Instead we want:
//
// fn foo(x: u32) {
// --------------
// | |
// | x_span
// fn_span
//
// which is...less weird, at least. In fact, in general, if
// the rightmost span overlaps with any other span, we should
// use the "hang below" version, so we can at least make it
// clear where the span *starts*.
let mut labeled_annotations = &labeled_annotations[..];
match labeled_annotations.split_last().unwrap() {
(last, previous) => {
if previous.iter()
.chain(&unlabeled_annotations)
.all(|a| !overlaps(a, last)) {
// append the label afterwards; we keep it in a separate
// string
let highlight_label: String = format!(" {}", last.label.as_ref().unwrap());
if last.is_primary {
buffer.append(line_offset + 1, &highlight_label, Style::LabelPrimary);
} else {
buffer.append(line_offset + 1, &highlight_label, Style::LabelSecondary);
}
labeled_annotations = previous;
}
}
}
// If that's the last annotation, we're done
if labeled_annotations.is_empty() {
return;
}
for (index, annotation) in labeled_annotations.iter().enumerate() {
// Leave:
// - 1 extra line
// - One line for each thing that comes after
let comes_after = labeled_annotations.len() - index - 1;
let blank_lines = 3 + comes_after;
// For each blank line, draw a `|` at our column. The
// text ought to be long enough for this.
for index in 2..blank_lines {
if annotation.is_primary {
buffer.putc(line_offset + index,
width_offset + annotation.start_col,
'|',
Style::UnderlinePrimary);
} else {
buffer.putc(line_offset + index,
width_offset + annotation.start_col,
'|',
Style::UnderlineSecondary);
}
draw_col_separator(buffer, line_offset + index, width_offset - 2);
}
if annotation.is_primary {
buffer.puts(line_offset + blank_lines,
width_offset + annotation.start_col,
annotation.label.as_ref().unwrap(),
Style::LabelPrimary);
} else {
buffer.puts(line_offset + blank_lines,
width_offset + annotation.start_col,
annotation.label.as_ref().unwrap(),
Style::LabelSecondary);
}
draw_col_separator(buffer, line_offset + blank_lines, width_offset - 2);
}
}
fn get_multispan_max_line_num(&mut self, msp: &MultiSpan) -> usize {
let mut max = 0;
if let Some(ref cm) = self.cm {
for primary_span in msp.primary_spans() {
if primary_span != &DUMMY_SP && primary_span != &COMMAND_LINE_SP {
let hi = cm.lookup_char_pos(primary_span.hi);
if hi.line > max {
max = hi.line;
}
}
}
for span_label in msp.span_labels() {
if span_label.span != DUMMY_SP && span_label.span != COMMAND_LINE_SP {
let hi = cm.lookup_char_pos(span_label.span.hi);
if hi.line > max {
max = hi.line;
}
}
}
}
max
}
fn get_max_line_num(&mut self, db: &DiagnosticBuilder) -> usize {
let mut max = 0;
let primary = self.get_multispan_max_line_num(&db.span);
max = if primary > max { primary } else { max };
for sub in &db.children {
let sub_result = self.get_multispan_max_line_num(&sub.span);
max = if sub_result > max { primary } else { max };
}
max
}
fn emit_message_default(&mut self,
msp: &MultiSpan,
msg: &str,
code: &Option<String>,
level: &Level,
max_line_num_len: usize,
is_secondary: bool)
-> io::Result<()> {
let mut buffer = StyledBuffer::new();
if msp.primary_spans().is_empty() && msp.span_labels().is_empty() && is_secondary {
// This is a secondary message with no span info
for _ in 0..max_line_num_len {
buffer.prepend(0, " ", Style::NoStyle);
}
draw_note_separator(&mut buffer, 0, max_line_num_len + 1);
buffer.append(0, &level.to_string(), Style::HeaderMsg);
buffer.append(0, ": ", Style::NoStyle);
buffer.append(0, msg, Style::NoStyle);
}
else {
buffer.append(0, &level.to_string(), Style::Level(level.clone()));
match code {
&Some(ref code) => {
buffer.append(0, "[", Style::Level(level.clone()));
buffer.append(0, &code, Style::Level(level.clone()));
buffer.append(0, "]", Style::Level(level.clone()));
}
_ => {}
}
buffer.append(0, ": ", Style::HeaderMsg);
buffer.append(0, msg, Style::HeaderMsg);
}
// Preprocess all the annotations so that they are grouped by file and by line number
// This helps us quickly iterate over the whole message (including secondary file spans)
let mut annotated_files = self.preprocess_annotations(msp);
// Make sure our primary file comes first
let primary_lo =
if let (Some(ref cm), Some(ref primary_span)) = (self.cm.as_ref(),
msp.primary_span().as_ref()) {
if primary_span != &&DUMMY_SP && primary_span != &&COMMAND_LINE_SP {
cm.lookup_char_pos(primary_span.lo)
}
else {
emit_to_destination(&buffer.render(), level, &mut self.dst)?;
return Ok(());
}
} else {
// If we don't have span information, emit and exit
emit_to_destination(&buffer.render(), level, &mut self.dst)?;
return Ok(());
};
if let Ok(pos) =
annotated_files.binary_search_by(|x| x.file.name.cmp(&primary_lo.file.name)) {
annotated_files.swap(0, pos);
}
// Print out the annotate source lines that correspond with the error
for annotated_file in annotated_files {
// print out the span location and spacer before we print the annotated source
// to do this, we need to know if this span will be primary
let is_primary = primary_lo.file.name == annotated_file.file.name;
if is_primary {
// remember where we are in the output buffer for easy reference
let buffer_msg_line_offset = buffer.num_lines();
buffer.prepend(buffer_msg_line_offset, "--> ", Style::LineNumber);
let loc = primary_lo.clone();
buffer.append(buffer_msg_line_offset,
&format!("{}:{}:{}", loc.file.name, loc.line, loc.col.0 + 1),
Style::LineAndColumn);
for _ in 0..max_line_num_len {
buffer.prepend(buffer_msg_line_offset, " ", Style::NoStyle);
}
} else {
// remember where we are in the output buffer for easy reference
let buffer_msg_line_offset = buffer.num_lines();
// Add spacing line
draw_col_separator(&mut buffer, buffer_msg_line_offset, max_line_num_len + 1);
// Then, the secondary file indicator
buffer.prepend(buffer_msg_line_offset + 1, "::: ", Style::LineNumber);
buffer.append(buffer_msg_line_offset + 1,
&annotated_file.file.name,
Style::LineAndColumn);
for _ in 0..max_line_num_len {
buffer.prepend(buffer_msg_line_offset + 1, " ", Style::NoStyle);
}
}
// Put in the spacer between the location and annotated source
let buffer_msg_line_offset = buffer.num_lines();
draw_col_separator_no_space(&mut buffer, buffer_msg_line_offset, max_line_num_len + 1);
// Next, output the annotate source for this file
for line_idx in 0..annotated_file.lines.len() {
self.render_source_line(&mut buffer,
annotated_file.file.clone(),
&annotated_file.lines[line_idx],
3 + max_line_num_len);
// check to see if we need to print out or elide lines that come between
// this annotated line and the next one
if line_idx < (annotated_file.lines.len() - 1) {
let line_idx_delta = annotated_file.lines[line_idx + 1].line_index -
annotated_file.lines[line_idx].line_index;
if line_idx_delta > 2 {
let last_buffer_line_num = buffer.num_lines();
buffer.puts(last_buffer_line_num, 0, "...", Style::LineNumber);
} else if line_idx_delta == 2 {
let unannotated_line = annotated_file.file
.get_line(annotated_file.lines[line_idx].line_index)
.unwrap_or("");
let last_buffer_line_num = buffer.num_lines();
buffer.puts(last_buffer_line_num,
0,
&(annotated_file.lines[line_idx + 1].line_index - 1)
.to_string(),
Style::LineNumber);
draw_col_separator(&mut buffer, last_buffer_line_num, 1 + max_line_num_len);
buffer.puts(last_buffer_line_num,
3 + max_line_num_len,
&unannotated_line,
Style::Quotation);
}
}
}
}
if let Some(ref primary_span) = msp.primary_span().as_ref() {
self.render_macro_backtrace_old_school(primary_span, &mut buffer)?;
}
// final step: take our styled buffer, render it, then output it
emit_to_destination(&buffer.render(), level, &mut self.dst)?;
Ok(())
}
fn emit_suggestion_default(&mut self,
suggestion: &CodeSuggestion,
level: &Level,
msg: &str,
max_line_num_len: usize)
-> io::Result<()> {
use std::borrow::Borrow;
let primary_span = suggestion.msp.primary_span().unwrap();
if let Some(ref cm) = self.cm {
let mut buffer = StyledBuffer::new();
buffer.append(0, &level.to_string(), Style::Level(level.clone()));
buffer.append(0, ": ", Style::HeaderMsg);
buffer.append(0, msg, Style::HeaderMsg);
let lines = cm.span_to_lines(primary_span).unwrap();
assert!(!lines.lines.is_empty());
let complete = suggestion.splice_lines(cm.borrow());
// print the suggestion without any line numbers, but leave
// space for them. This helps with lining up with previous
// snippets from the actual error being reported.
let mut lines = complete.lines();
let mut row_num = 1;
for line in lines.by_ref().take(MAX_HIGHLIGHT_LINES) {
draw_col_separator(&mut buffer, row_num, max_line_num_len + 1);
buffer.append(row_num, line, Style::NoStyle);
row_num += 1;
}
// if we elided some lines, add an ellipsis
if let Some(_) = lines.next() {
buffer.append(row_num, "...", Style::NoStyle);
}
emit_to_destination(&buffer.render(), level, &mut self.dst)?;
}
Ok(())
}
fn emit_messages_default(&mut self, db: &DiagnosticBuilder) {
let max_line_num = self.get_max_line_num(db);
let max_line_num_len = max_line_num.to_string().len();
match self.emit_message_default(&db.span,
&db.message,
&db.code,
&db.level,
max_line_num_len,
false) {
Ok(()) => {
if !db.children.is_empty() {
let mut buffer = StyledBuffer::new();
draw_col_separator_no_space(&mut buffer, 0, max_line_num_len + 1);
match emit_to_destination(&buffer.render(), &db.level, &mut self.dst) {
Ok(()) => (),
Err(e) => panic!("failed to emit error: {}", e)
}
}
for child in &db.children {
match child.render_span {
Some(FullSpan(ref msp)) => {
match self.emit_message_default(msp,
&child.message,
&None,
&child.level,
max_line_num_len,
true) {
Err(e) => panic!("failed to emit error: {}", e),
_ => ()
}
},
Some(Suggestion(ref cs)) => {
match self.emit_suggestion_default(cs,
&child.level,
&child.message,
max_line_num_len) {
Err(e) => panic!("failed to emit error: {}", e),
_ => ()
}
},
None => {
match self.emit_message_default(&child.span,
&child.message,
&None,
&child.level,
max_line_num_len,
true) {
Err(e) => panic!("failed to emit error: {}", e),
_ => ()
}
}
}
}
}
Err(e) => panic!("failed to emit error: {}", e)
}
match write!(&mut self.dst, "\n") {
Err(e) => panic!("failed to emit error: {}", e),
_ => ()
}
}
fn render_macro_backtrace_old_school(&mut self,
sp: &Span,
buffer: &mut StyledBuffer) -> io::Result<()> {
if let Some(ref cm) = self.cm {
for trace in cm.macro_backtrace(sp.clone()) {
let line_offset = buffer.num_lines();
let mut diag_string =
format!("in this expansion of {}", trace.macro_decl_name);
if let Some(def_site_span) = trace.def_site_span {
diag_string.push_str(
&format!(" (defined in {})",
cm.span_to_filename(def_site_span)));
}
let snippet = cm.span_to_string(trace.call_site);
buffer.append(line_offset, &format!("{} ", snippet), Style::NoStyle);
buffer.append(line_offset, "note", Style::Level(Level::Note));
buffer.append(line_offset, ": ", Style::NoStyle);
buffer.append(line_offset, &diag_string, Style::OldSchoolNoteText);
}
}
Ok(())
}
}
fn draw_col_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
buffer.puts(line, col, "| ", Style::LineNumber);
}
fn draw_col_separator_no_space(buffer: &mut StyledBuffer, line: usize, col: usize) {
buffer.puts(line, col, "|", Style::LineNumber);
}
fn draw_note_separator(buffer: &mut StyledBuffer, line: usize, col: usize) {
buffer.puts(line, col, "= ", Style::LineNumber);
}
fn overlaps(a1: &Annotation, a2: &Annotation) -> bool {
(a2.start_col..a2.end_col).contains(a1.start_col) ||
(a1.start_col..a1.end_col).contains(a2.start_col)
}
fn emit_to_destination(rendered_buffer: &Vec<Vec<StyledString>>,
lvl: &Level,
dst: &mut Destination) -> io::Result<()> {
for line in rendered_buffer {
for part in line {
dst.apply_style(lvl.clone(), part.style)?;
write!(dst, "{}", part.text)?;
dst.reset_attrs()?;
}
write!(dst, "\n")?;
}
Ok(())
}
#[cfg(unix)]
fn stderr_isatty() -> bool {
use libc;
unsafe { libc::isatty(libc::STDERR_FILENO) != 0 }
}
#[cfg(windows)]
fn stderr_isatty() -> bool {
type DWORD = u32;
type BOOL = i32;
type HANDLE = *mut u8;
const STD_ERROR_HANDLE: DWORD = -12i32 as DWORD;
extern "system" {
fn GetStdHandle(which: DWORD) -> HANDLE;
fn GetConsoleMode(hConsoleHandle: HANDLE,
lpMode: *mut DWORD) -> BOOL;
}
unsafe {
let handle = GetStdHandle(STD_ERROR_HANDLE);
let mut out = 0;
GetConsoleMode(handle, &mut out) != 0
}
}
pub enum Destination {
Terminal(Box<term::StderrTerminal>),
Raw(Box<Write + Send>),
}
impl Destination {
fn from_stderr() -> Destination {
match term::stderr() {
Some(t) => Terminal(t),
None => Raw(Box::new(io::stderr())),
}
}
fn apply_style(&mut self,
lvl: Level,
style: Style)
-> io::Result<()> {
match style {
Style::FileNameStyle | Style::LineAndColumn => {}
Style::LineNumber => {
try!(self.start_attr(term::Attr::Bold));
try!(self.start_attr(term::Attr::ForegroundColor(term::color::BRIGHT_BLUE)));
}
Style::ErrorCode => {
try!(self.start_attr(term::Attr::Bold));
try!(self.start_attr(term::Attr::ForegroundColor(term::color::BRIGHT_MAGENTA)));
}
Style::Quotation => {}
Style::OldSchoolNote => {
try!(self.start_attr(term::Attr::Bold));
try!(self.start_attr(term::Attr::ForegroundColor(term::color::BRIGHT_GREEN)));
}
Style::OldSchoolNoteText | Style::HeaderMsg => {
try!(self.start_attr(term::Attr::Bold));
}
Style::UnderlinePrimary | Style::LabelPrimary => {
try!(self.start_attr(term::Attr::Bold));
try!(self.start_attr(term::Attr::ForegroundColor(lvl.color())));
}
Style::UnderlineSecondary |
Style::LabelSecondary => {
try!(self.start_attr(term::Attr::Bold));
try!(self.start_attr(term::Attr::ForegroundColor(term::color::BRIGHT_BLUE)));
}
Style::NoStyle => {}
Style::Level(l) => {
try!(self.start_attr(term::Attr::Bold));
try!(self.start_attr(term::Attr::ForegroundColor(l.color())));
}
}
Ok(())
}
fn start_attr(&mut self, attr: term::Attr) -> io::Result<()> {
match *self {
Terminal(ref mut t) => { t.attr(attr)?; }
Raw(_) => { }
}
Ok(())
}
fn reset_attrs(&mut self) -> io::Result<()> {
match *self {
Terminal(ref mut t) => { t.reset()?; }
Raw(_) => { }
}
Ok(())
}
}
impl Write for Destination {
fn write(&mut self, bytes: &[u8]) -> io::Result<usize> {
match *self {
Terminal(ref mut t) => t.write(bytes),
Raw(ref mut w) => w.write(bytes),
}
}
fn flush(&mut self) -> io::Result<()> {
match *self {
Terminal(ref mut t) => t.flush(),
Raw(ref mut w) => w.flush(),
}
}
}