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Slightly refactor syntax_ext/format #53215

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merged 2 commits into from
Aug 9, 2018
Merged

Slightly refactor syntax_ext/format #53215

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c7646d5
Refactor expand_preparsed_format_args
ljedrz Aug 8, 2018
aab063a
Use Cow<str> in describe_num_args
ljedrz Aug 9, 2018
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131 changes: 70 additions & 61 deletions src/libsyntax_ext/format.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,8 +14,7 @@ use self::Position::*;
use fmt_macros as parse;

use syntax::ast;
use syntax::ext::base;
use syntax::ext::base::*;
use syntax::ext::base::{self, *};
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[not actionable] This change is ok and valid, I'm just finding odd to use foo::{self, *}; :)

use syntax::ext::build::AstBuilder;
use syntax::feature_gate;
use syntax::parse::token;
Expand All @@ -24,6 +23,7 @@ use syntax::symbol::Symbol;
use syntax::tokenstream;
use syntax_pos::{MultiSpan, Span, DUMMY_SP};

use std::borrow::Cow;
use std::collections::hash_map::Entry;
use std::collections::{HashMap, HashSet};

Expand Down Expand Up @@ -143,8 +143,10 @@ fn parse_args(ecx: &mut ExtCtxt,
ecx.span_err(sp, "requires at least a format string argument");
return None;
}

let fmtstr = panictry!(p.parse_expr());
let mut named = false;

while p.token != token::Eof {
if !p.eat(&token::Comma) {
ecx.span_err(p.span, "expected token: `,`");
Expand Down Expand Up @@ -264,11 +266,11 @@ impl<'a, 'b> Context<'a, 'b> {
}
}

fn describe_num_args(&self) -> String {
fn describe_num_args(&self) -> Cow<str> {
match self.args.len() {
0 => "no arguments were given".to_string(),
1 => "there is 1 argument".to_string(),
x => format!("there are {} arguments", x),
0 => "no arguments were given".into(),
1 => "there is 1 argument".into(),
x => format!("there are {} arguments", x).into(),
}
}

Expand Down Expand Up @@ -772,8 +774,10 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
// `ArgumentType` does not derive `Clone`.
let arg_types: Vec<_> = (0..args.len()).map(|_| Vec::new()).collect();
let arg_unique_types: Vec<_> = (0..args.len()).map(|_| Vec::new()).collect();

let mut macsp = ecx.call_site();
macsp = macsp.apply_mark(ecx.current_expansion.mark);

let msg = "format argument must be a string literal";
let fmt_sp = efmt.span;
let fmt = match expr_to_spanned_string(ecx, efmt, msg) {
Expand All @@ -796,11 +800,46 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
return DummyResult::raw_expr(sp);
}
};

let is_literal = match ecx.codemap().span_to_snippet(fmt_sp) {
Ok(ref s) if s.starts_with("\"") || s.starts_with("r#") => true,
_ => false,
};

let fmt_str = &*fmt.node.0.as_str();
let str_style = match fmt.node.1 {
ast::StrStyle::Cooked => None,
ast::StrStyle::Raw(raw) => Some(raw as usize),
};

let mut parser = parse::Parser::new(fmt_str, str_style);

let mut unverified_pieces = Vec::new();
while let Some(piece) = parser.next() {
if !parser.errors.is_empty() {
break;
} else {
unverified_pieces.push(piece);
}
}

if !parser.errors.is_empty() {
let err = parser.errors.remove(0);
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This is not introduced in this change, but now I'm intrigued wether parser.errors.len() could be > 1 and if it could, what the correct behavior would be...

let sp = fmt.span.from_inner_byte_pos(err.start, err.end);
let mut e = ecx.struct_span_err(sp, &format!("invalid format string: {}",
err.description));
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nitpick: formatting

e.span_label(sp, err.label + " in format string");
if let Some(note) = err.note {
e.note(&note);
}
e.emit();
return DummyResult::raw_expr(sp);
}

let arg_spans = parser.arg_places.iter()
.map(|&(start, end)| fmt.span.from_inner_byte_pos(start, end))
.collect();

let mut cx = Context {
ecx,
args,
Expand All @@ -815,42 +854,22 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
count_positions_count: 0,
count_args_index_offset: 0,
literal: String::new(),
pieces: Vec::new(),
str_pieces: Vec::new(),
pieces: Vec::with_capacity(unverified_pieces.len()),
str_pieces: Vec::with_capacity(unverified_pieces.len()),
all_pieces_simple: true,
macsp,
fmtsp: fmt.span,
invalid_refs: Vec::new(),
arg_spans: Vec::new(),
arg_spans,
is_literal,
};

let fmt_str = &*fmt.node.0.as_str();
let str_style = match fmt.node.1 {
ast::StrStyle::Cooked => None,
ast::StrStyle::Raw(raw) => Some(raw as usize),
};
let mut parser = parse::Parser::new(fmt_str, str_style);
let mut unverified_pieces = vec![];
let mut pieces = vec![];

while let Some(piece) = parser.next() {
if !parser.errors.is_empty() {
break;
}
unverified_pieces.push(piece);
}

cx.arg_spans = parser.arg_places.iter()
.map(|&(start, end)| fmt.span.from_inner_byte_pos(start, end))
.collect();

// This needs to happen *after* the Parser has consumed all pieces to create all the spans
for mut piece in unverified_pieces {
let pieces = unverified_pieces.into_iter().map(|mut piece| {
cx.verify_piece(&piece);
cx.resolve_name_inplace(&mut piece);
pieces.push(piece);
}
piece
}).collect::<Vec<_>>();

let numbered_position_args = pieces.iter().any(|arg: &parse::Piece| {
match *arg {
Expand All @@ -867,6 +886,7 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
cx.build_index_map();

let mut arg_index_consumed = vec![0usize; cx.arg_index_map.len()];

for piece in pieces {
if let Some(piece) = cx.build_piece(&piece, &mut arg_index_consumed) {
let s = cx.build_literal_string();
Expand All @@ -875,18 +895,6 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,
}
}

if !parser.errors.is_empty() {
let err = parser.errors.remove(0);
let sp = cx.fmtsp.from_inner_byte_pos(err.start, err.end);
let mut e = cx.ecx.struct_span_err(sp, &format!("invalid format string: {}",
err.description));
e.span_label(sp, err.label + " in format string");
if let Some(note) = err.note {
e.note(&note);
}
e.emit();
return DummyResult::raw_expr(sp);
}
if !cx.literal.is_empty() {
let s = cx.build_literal_string();
cx.str_pieces.push(s);
Expand All @@ -898,24 +906,25 @@ pub fn expand_preparsed_format_args(ecx: &mut ExtCtxt,

// Make sure that all arguments were used and all arguments have types.
let num_pos_args = cx.args.len() - cx.names.len();
let mut errs = vec![];
for (i, ty) in cx.arg_types.iter().enumerate() {
if ty.len() == 0 {
if cx.count_positions.contains_key(&i) {
continue;
}
let msg = if i >= num_pos_args {
// named argument
"named argument never used"
} else {
// positional argument
"argument never used"
};
errs.push((cx.args[i].span, msg));
}
}

let errs = cx.arg_types
.iter()
.enumerate()
.filter(|(i, ty)| ty.is_empty() && !cx.count_positions.contains_key(&i))
.map(|(i, _)| {
let msg = if i >= num_pos_args {
// named argument
"named argument never used"
} else {
// positional argument
"argument never used"
};
(cx.args[i].span, msg)
})
.collect::<Vec<_>>();

let errs_len = errs.len();
if errs_len > 0 {
if !errs.is_empty() {
let args_used = cx.arg_types.len() - errs_len;
let args_unused = errs_len;

Expand Down