1 // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
12 use std::cmp::Ordering;
15 use syntax::ast::{self, Attribute, MetaItem, MetaItemKind, NestedMetaItem, NestedMetaItemKind,
17 use syntax::codemap::{BytePos, Span, NO_EXPANSION};
20 use rewrite::{Rewrite, RewriteContext};
22 // When we get scoped annotations, we should have rustfmt::skip.
23 const SKIP_ANNOTATION: &'static str = "rustfmt_skip";
25 // Computes the length of a string's last line, minus offset.
26 pub fn extra_offset(text: &str, shape: Shape) -> usize {
27 match text.rfind('\n') {
28 // 1 for newline character
29 Some(idx) => text.len()
30 .checked_sub(idx + 1 + shape.used_width())
36 // Uses Cow to avoid allocating in the common cases.
37 pub fn format_visibility(vis: &Visibility) -> Cow<'static, str> {
39 Visibility::Public => Cow::from("pub "),
40 Visibility::Inherited => Cow::from(""),
41 Visibility::Crate(_) => Cow::from("pub(crate) "),
42 Visibility::Restricted { ref path, .. } => {
43 let Path { ref segments, .. } = **path;
44 let mut segments_iter = segments.iter().map(|seg| seg.identifier.name.to_string());
48 .expect("Non-global path in pub(restricted)?");
50 let is_keyword = |s: &str| s == "self" || s == "super";
51 let path = segments_iter.collect::<Vec<_>>().join("::");
52 let in_str = if is_keyword(&path) { "" } else { "in " };
54 Cow::from(format!("pub({}{}) ", in_str, path))
60 pub fn format_unsafety(unsafety: ast::Unsafety) -> &'static str {
62 ast::Unsafety::Unsafe => "unsafe ",
63 ast::Unsafety::Normal => "",
68 pub fn format_mutability(mutability: ast::Mutability) -> &'static str {
70 ast::Mutability::Mutable => "mut ",
71 ast::Mutability::Immutable => "",
76 pub fn format_abi(abi: abi::Abi, explicit_abi: bool) -> String {
77 if abi == abi::Abi::C && !explicit_abi {
80 format!("extern {} ", abi)
84 // The width of the first line in s.
86 pub fn first_line_width(s: &str) -> usize {
93 // The width of the last line in s.
95 pub fn last_line_width(s: &str) -> usize {
97 Some(n) => s.len() - n - 1,
103 pub fn trimmed_last_line_width(s: &str) -> usize {
104 match s.rfind('\n') {
105 Some(n) => s[(n + 1)..].trim().len(),
106 None => s.trim().len(),
111 pub fn last_line_extendable(s: &str) -> bool {
112 s.lines().last().map_or(false, |s| {
113 s.ends_with("\"#") ||
116 .all(|c| c == ')' || c == ']' || c == '}' || c == '?')
121 fn is_skip(meta_item: &MetaItem) -> bool {
122 match meta_item.node {
123 MetaItemKind::Word => meta_item.name == SKIP_ANNOTATION,
124 MetaItemKind::List(ref l) => {
125 meta_item.name == "cfg_attr" && l.len() == 2 && is_skip_nested(&l[1])
132 fn is_skip_nested(meta_item: &NestedMetaItem) -> bool {
133 match meta_item.node {
134 NestedMetaItemKind::MetaItem(ref mi) => is_skip(mi),
135 NestedMetaItemKind::Literal(_) => false,
140 pub fn contains_skip(attrs: &[Attribute]) -> bool {
143 .any(|a| a.meta().map_or(false, |a| is_skip(&a)))
146 // Find the end of a TyParam
148 pub fn end_typaram(typaram: &ast::TyParam) -> BytePos {
152 .map_or(typaram.span, |bound| match *bound {
153 ast::RegionTyParamBound(ref lt) => lt.span,
154 ast::TraitTyParamBound(ref prt, _) => prt.span,
160 pub fn semicolon_for_expr(context: &RewriteContext, expr: &ast::Expr) -> bool {
162 ast::ExprKind::Ret(..) | ast::ExprKind::Continue(..) | ast::ExprKind::Break(..) => {
163 context.config.trailing_semicolon()
170 pub fn semicolon_for_stmt(context: &RewriteContext, stmt: &ast::Stmt) -> bool {
172 ast::StmtKind::Semi(ref expr) => match expr.node {
173 ast::ExprKind::While(..) |
174 ast::ExprKind::WhileLet(..) |
175 ast::ExprKind::Loop(..) |
176 ast::ExprKind::ForLoop(..) => false,
177 ast::ExprKind::Break(..) | ast::ExprKind::Continue(..) | ast::ExprKind::Ret(..) => {
178 context.config.trailing_semicolon()
182 ast::StmtKind::Expr(..) => false,
188 pub fn stmt_expr(stmt: &ast::Stmt) -> Option<&ast::Expr> {
190 ast::StmtKind::Expr(ref expr) => Some(expr),
196 pub fn trim_newlines(input: &str) -> &str {
197 match input.find(|c| c != '\n' && c != '\r') {
199 let end = input.rfind(|c| c != '\n' && c != '\r').unwrap_or(0) + 1;
206 // Macro for deriving implementations of Serialize/Deserialize for enums
208 macro_rules! impl_enum_serialize_and_deserialize {
209 ( $e:ident, $( $x:ident ),* ) => {
210 impl ::serde::ser::Serialize for $e {
211 fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
212 where S: ::serde::ser::Serializer
214 use serde::ser::Error;
216 // We don't know whether the user of the macro has given us all options.
217 #[allow(unreachable_patterns)]
220 $e::$x => serializer.serialize_str(stringify!($x)),
223 Err(S::Error::custom(format!("Cannot serialize {:?}", self)))
229 impl<'de> ::serde::de::Deserialize<'de> for $e {
230 fn deserialize<D>(d: D) -> Result<Self, D::Error>
231 where D: ::serde::Deserializer<'de> {
232 use std::ascii::AsciiExt;
233 use serde::de::{Error, Visitor};
234 use std::marker::PhantomData;
236 struct StringOnly<T>(PhantomData<T>);
237 impl<'de, T> Visitor<'de> for StringOnly<T>
238 where T: ::serde::Deserializer<'de> {
240 fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
241 formatter.write_str("string")
243 fn visit_str<E>(self, value: &str) -> Result<String, E> {
244 Ok(String::from(value))
247 let s = d.deserialize_string(StringOnly::<D>(PhantomData))?;
249 if stringify!($x).eq_ignore_ascii_case(&s) {
253 static ALLOWED: &'static[&str] = &[$(stringify!($x),)*];
254 Err(D::Error::unknown_variant(&s, ALLOWED))
258 impl ::std::str::FromStr for $e {
259 type Err = &'static str;
261 fn from_str(s: &str) -> Result<Self, Self::Err> {
262 use std::ascii::AsciiExt;
264 if stringify!($x).eq_ignore_ascii_case(s) {
272 impl ::config::ConfigType for $e {
273 fn doc_hint() -> String {
274 let mut variants = Vec::new();
276 variants.push(stringify!($x));
278 format!("[{}]", variants.join("|"))
284 // Same as try!, but for Option
286 macro_rules! try_opt {
287 ($expr:expr) => (match $expr {
289 None => { return None; }
295 match writeln!(&mut ::std::io::stderr(), $($arg)* ) {
297 Err(x) => panic!("Unable to write to stderr: {}", x),
302 // For format_missing and last_pos, need to use the source callsite (if applicable).
303 // Required as generated code spans aren't guaranteed to follow on from the last span.
304 macro_rules! source {
305 ($this:ident, $sp: expr) => {
306 $sp.source_callsite()
310 pub fn mk_sp(lo: BytePos, hi: BytePos) -> Span {
318 // Wraps string-like values in an Option. Returns Some when the string adheres
319 // to the Rewrite constraints defined for the Rewrite trait and else otherwise.
320 pub fn wrap_str<S: AsRef<str>>(s: S, max_width: usize, shape: Shape) -> Option<S> {
322 let snippet = s.as_ref();
324 if !snippet.is_empty() {
325 if !snippet.contains('\n') && snippet.len() > shape.width {
328 let mut lines = snippet.lines();
330 if lines.next().unwrap().len() > shape.width {
334 // The other lines must fit within the maximum width.
335 if lines.any(|line| line.len() > max_width) {
339 // `width` is the maximum length of the last line, excluding
341 // A special check for the last line, since the caller may
342 // place trailing characters on this line.
343 if snippet.lines().rev().next().unwrap().len() > shape.used_width() + shape.width {
353 impl Rewrite for String {
354 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
355 wrap_str(self, context.config.max_width(), shape).map(ToOwned::to_owned)
359 // Binary search in integer range. Returns the first Ok value returned by the
361 // The callback takes an integer and returns either an Ok, or an Err indicating
362 // whether the `guess' was too high (Ordering::Less), or too low.
363 // This function is guaranteed to try to the hi value first.
364 pub fn binary_search<C, T>(mut lo: usize, mut hi: usize, callback: C) -> Option<T>
366 C: Fn(usize) -> Result<T, Ordering>,
371 match callback(middle) {
372 Ok(val) => return Some(val),
373 Err(Ordering::Less) => {
380 middle = (hi + lo) / 2;
387 pub fn colon_spaces(before: bool, after: bool) -> &'static str {
388 match (before, after) {
389 (true, true) => " : ",
390 (true, false) => " :",
391 (false, true) => ": ",
392 (false, false) => ":",
397 pub fn paren_overhead(context: &RewriteContext) -> usize {
398 if context.config.spaces_within_parens() {
406 fn bin_search_test() {
407 let closure = |i| match i {
409 j if j > 4 => Err(Ordering::Less),
410 j if j < 4 => Err(Ordering::Greater),
414 assert_eq!(Some(()), binary_search(1, 10, &closure));
415 assert_eq!(None, binary_search(1, 3, &closure));
416 assert_eq!(Some(()), binary_search(0, 44, &closure));
417 assert_eq!(Some(()), binary_search(4, 125, &closure));
418 assert_eq!(None, binary_search(6, 100, &closure));
421 pub fn left_most_sub_expr(e: &ast::Expr) -> &ast::Expr {
423 ast::ExprKind::InPlace(ref e, _) |
424 ast::ExprKind::Call(ref e, _) |
425 ast::ExprKind::Binary(_, ref e, _) |
426 ast::ExprKind::Cast(ref e, _) |
427 ast::ExprKind::Type(ref e, _) |
428 ast::ExprKind::Assign(ref e, _) |
429 ast::ExprKind::AssignOp(_, ref e, _) |
430 ast::ExprKind::Field(ref e, _) |
431 ast::ExprKind::TupField(ref e, _) |
432 ast::ExprKind::Index(ref e, _) |
433 ast::ExprKind::Range(Some(ref e), _, _) |
434 ast::ExprKind::Try(ref e) => left_most_sub_expr(e),