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;
14 use itertools::Itertools;
16 use syntax::ast::{self, Visibility, Attribute, MetaItem, MetaItemKind, NestedMetaItem,
17 NestedMetaItemKind, Path};
18 use syntax::codemap::BytePos;
22 use rewrite::{Rewrite, RewriteContext};
26 // Computes the length of a string's last line, minus offset.
27 pub fn extra_offset(text: &str, shape: Shape) -> usize {
28 match text.rfind('\n') {
29 // 1 for newline character
32 .checked_sub(idx + 1 + shape.used_width())
39 // Uses Cow to avoid allocating in the common cases.
40 pub fn format_visibility(vis: &Visibility) -> Cow<'static, str> {
42 Visibility::Public => Cow::from("pub "),
43 Visibility::Inherited => Cow::from(""),
44 Visibility::Crate(_) => Cow::from("pub(crate) "),
45 Visibility::Restricted { ref path, .. } => {
46 let Path { ref segments, .. } = **path;
47 let mut segments_iter = segments.iter().map(|seg| seg.identifier.name.as_str());
51 .expect("Non-global path in pub(restricted)?");
54 Cow::from(format!("pub({}) ", segments_iter.join("::")))
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,
102 pub fn trimmed_last_line_width(s: &str) -> usize {
103 match s.rfind('\n') {
104 Some(n) => s[(n + 1)..].trim().len(),
105 None => s.trim().len(),
110 fn is_skip(meta_item: &MetaItem) -> bool {
111 match meta_item.node {
112 MetaItemKind::Word => meta_item.name == SKIP_ANNOTATION,
113 MetaItemKind::List(ref l) => {
114 meta_item.name == "cfg_attr" && l.len() == 2 && is_skip_nested(&l[1])
121 fn is_skip_nested(meta_item: &NestedMetaItem) -> bool {
122 match meta_item.node {
123 NestedMetaItemKind::MetaItem(ref mi) => is_skip(mi),
124 NestedMetaItemKind::Literal(_) => false,
129 pub fn contains_skip(attrs: &[Attribute]) -> bool {
130 attrs.iter().any(|a| is_skip(&a.value))
133 // Find the end of a TyParam
135 pub fn end_typaram(typaram: &ast::TyParam) -> BytePos {
139 .map_or(typaram.span, |bound| match *bound {
140 ast::RegionTyParamBound(ref lt) => lt.span,
141 ast::TraitTyParamBound(ref prt, _) => prt.span,
147 pub fn semicolon_for_expr(expr: &ast::Expr) -> bool {
149 ast::ExprKind::Ret(..) |
150 ast::ExprKind::Continue(..) |
151 ast::ExprKind::Break(..) => true,
157 pub fn semicolon_for_stmt(stmt: &ast::Stmt) -> bool {
159 ast::StmtKind::Semi(ref expr) => {
161 ast::ExprKind::While(..) |
162 ast::ExprKind::WhileLet(..) |
163 ast::ExprKind::Loop(..) |
164 ast::ExprKind::ForLoop(..) => false,
168 ast::StmtKind::Expr(..) => false,
174 pub fn stmt_expr(stmt: &ast::Stmt) -> Option<&ast::Expr> {
176 ast::StmtKind::Expr(ref expr) => Some(expr),
182 pub fn trim_newlines(input: &str) -> &str {
183 match input.find(|c| c != '\n' && c != '\r') {
185 let end = input.rfind(|c| c != '\n' && c != '\r').unwrap_or(0) + 1;
192 // Macro for deriving implementations of Decodable for enums
194 macro_rules! impl_enum_decodable {
195 ( $e:ident, $( $x:ident ),* ) => {
196 impl<'de> ::serde::de::Deserialize<'de> for $e {
197 fn deserialize<D>(d: D) -> Result<Self, D::Error>
198 where D: ::serde::Deserializer<'de> {
199 use std::ascii::AsciiExt;
200 use serde::de::{Error, Visitor};
201 use std::marker::PhantomData;
203 struct StringOnly<T>(PhantomData<T>);
204 impl<'de, T> Visitor<'de> for StringOnly<T>
205 where T: ::serde::Deserializer<'de> {
207 fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
208 formatter.write_str("string")
210 fn visit_str<E>(self, value: &str) -> Result<String, E> {
211 Ok(String::from(value))
214 let s = d.deserialize_string(StringOnly::<D>(PhantomData))?;
216 if stringify!($x).eq_ignore_ascii_case(&s) {
220 static ALLOWED: &'static[&str] = &[$(stringify!($x),)*];
221 Err(D::Error::unknown_variant(&s, ALLOWED))
225 impl ::std::str::FromStr for $e {
226 type Err = &'static str;
228 fn from_str(s: &str) -> Result<Self, Self::Err> {
229 use std::ascii::AsciiExt;
231 if stringify!($x).eq_ignore_ascii_case(s) {
239 impl ::config::ConfigType for $e {
240 fn doc_hint() -> String {
241 let mut variants = Vec::new();
243 variants.push(stringify!($x));
245 format!("[{}]", variants.join("|"))
251 // Same as try!, but for Option
253 macro_rules! try_opt {
254 ($expr:expr) => (match $expr {
256 None => { return None; }
262 match writeln!(&mut ::std::io::stderr(), $($arg)* ) {
264 Err(x) => panic!("Unable to write to stderr: {}", x),
269 // For format_missing and last_pos, need to use the source callsite (if applicable).
270 // Required as generated code spans aren't guaranteed to follow on from the last span.
271 macro_rules! source {
272 ($this:ident, $sp: expr) => {
273 $this.codemap.source_callsite($sp)
277 // Wraps string-like values in an Option. Returns Some when the string adheres
278 // to the Rewrite constraints defined for the Rewrite trait and else otherwise.
279 pub fn wrap_str<S: AsRef<str>>(s: S, max_width: usize, shape: Shape) -> Option<S> {
281 let snippet = s.as_ref();
283 if !snippet.contains('\n') && snippet.len() > shape.width {
286 let mut lines = snippet.lines();
288 // The caller of this function has already placed `shape.offset`
289 // characters on the first line.
290 let first_line_max_len = try_opt!(max_width.checked_sub(shape.indent.width()));
291 if lines.next().unwrap().len() > first_line_max_len {
295 // The other lines must fit within the maximum width.
296 if lines.any(|line| line.len() > max_width) {
300 // `width` is the maximum length of the last line, excluding
302 // A special check for the last line, since the caller may
303 // place trailing characters on this line.
304 if snippet.lines().rev().next().unwrap().len() > shape.indent.width() + shape.width {
313 impl Rewrite for String {
314 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
315 wrap_str(self, context.config.max_width, shape).map(ToOwned::to_owned)
319 // Binary search in integer range. Returns the first Ok value returned by the
321 // The callback takes an integer and returns either an Ok, or an Err indicating
322 // whether the `guess' was too high (Ordering::Less), or too low.
323 // This function is guaranteed to try to the hi value first.
324 pub fn binary_search<C, T>(mut lo: usize, mut hi: usize, callback: C) -> Option<T>
325 where C: Fn(usize) -> Result<T, Ordering>
330 match callback(middle) {
331 Ok(val) => return Some(val),
332 Err(Ordering::Less) => {
339 middle = (hi + lo) / 2;
346 pub fn colon_spaces(before: bool, after: bool) -> &'static str {
347 match (before, after) {
348 (true, true) => " : ",
349 (true, false) => " :",
350 (false, true) => ": ",
351 (false, false) => ":",
356 fn bin_search_test() {
357 let closure = |i| match i {
359 j if j > 4 => Err(Ordering::Less),
360 j if j < 4 => Err(Ordering::Greater),
364 assert_eq!(Some(()), binary_search(1, 10, &closure));
365 assert_eq!(None, binary_search(1, 3, &closure));
366 assert_eq!(Some(()), binary_search(0, 44, &closure));
367 assert_eq!(Some(()), binary_search(4, 125, &closure));
368 assert_eq!(None, binary_search(6, 100, &closure));
371 pub fn left_most_sub_expr(e: &ast::Expr) -> &ast::Expr {
373 ast::ExprKind::InPlace(ref e, _) |
374 ast::ExprKind::Call(ref e, _) |
375 ast::ExprKind::Binary(_, ref e, _) |
376 ast::ExprKind::Cast(ref e, _) |
377 ast::ExprKind::Type(ref e, _) |
378 ast::ExprKind::Assign(ref e, _) |
379 ast::ExprKind::AssignOp(_, ref e, _) |
380 ast::ExprKind::Field(ref e, _) |
381 ast::ExprKind::TupField(ref e, _) |
382 ast::ExprKind::Index(ref e, _) |
383 ast::ExprKind::Range(Some(ref e), _, _) |
384 ast::ExprKind::Try(ref e) => left_most_sub_expr(e),