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, offset: Indent) -> usize {
28 match text.rfind('\n') {
29 // 1 for newline character
30 Some(idx) => text.len().checked_sub(idx + 1 + offset.width()).unwrap_or(0),
35 // Uses Cow to avoid allocating in the common cases.
36 pub fn format_visibility(vis: &Visibility) -> Cow<'static, str> {
38 Visibility::Public => Cow::from("pub "),
39 Visibility::Inherited => Cow::from(""),
40 Visibility::Crate(_) => Cow::from("pub(crate) "),
41 Visibility::Restricted { ref path, .. } => {
42 let Path { global, ref segments, .. } = **path;
43 let prefix = if global { "::" } else { "" };
44 let mut segments_iter = segments.iter().map(|seg| seg.identifier.name.as_str());
46 Cow::from(format!("pub({}{}) ", prefix, segments_iter.join("::")))
52 pub fn format_unsafety(unsafety: ast::Unsafety) -> &'static str {
54 ast::Unsafety::Unsafe => "unsafe ",
55 ast::Unsafety::Normal => "",
60 pub fn format_mutability(mutability: ast::Mutability) -> &'static str {
62 ast::Mutability::Mutable => "mut ",
63 ast::Mutability::Immutable => "",
68 pub fn format_abi(abi: abi::Abi, explicit_abi: bool) -> String {
69 if abi == abi::Abi::C && !explicit_abi {
72 format!("extern {} ", abi)
76 // The width of the first line in s.
78 pub fn first_line_width(s: &str) -> usize {
85 // The width of the last line in s.
87 pub fn last_line_width(s: &str) -> usize {
89 Some(n) => s.len() - n - 1,
94 pub fn trimmed_last_line_width(s: &str) -> usize {
96 Some(n) => s[(n + 1)..].trim().len(),
97 None => s.trim().len(),
102 fn is_skip(meta_item: &MetaItem) -> bool {
103 match meta_item.node {
104 MetaItemKind::Word => meta_item.name == SKIP_ANNOTATION,
105 MetaItemKind::List(ref l) => {
106 meta_item.name == "cfg_attr" && l.len() == 2 && is_skip_nested(&l[1])
113 fn is_skip_nested(meta_item: &NestedMetaItem) -> bool {
114 match meta_item.node {
115 NestedMetaItemKind::MetaItem(ref mi) => is_skip(mi),
116 NestedMetaItemKind::Literal(_) => false,
121 pub fn contains_skip(attrs: &[Attribute]) -> bool {
122 attrs.iter().any(|a| is_skip(&a.value))
125 // Find the end of a TyParam
127 pub fn end_typaram(typaram: &ast::TyParam) -> BytePos {
130 .map_or(typaram.span, |bound| match *bound {
131 ast::RegionTyParamBound(ref lt) => lt.span,
132 ast::TraitTyParamBound(ref prt, _) => prt.span,
138 pub fn semicolon_for_expr(expr: &ast::Expr) -> bool {
140 ast::ExprKind::Ret(..) |
141 ast::ExprKind::Continue(..) |
142 ast::ExprKind::Break(..) => true,
148 pub fn semicolon_for_stmt(stmt: &ast::Stmt) -> bool {
150 ast::StmtKind::Semi(ref expr) => {
152 ast::ExprKind::While(..) |
153 ast::ExprKind::WhileLet(..) |
154 ast::ExprKind::Loop(..) |
155 ast::ExprKind::ForLoop(..) => false,
159 ast::StmtKind::Expr(..) => false,
165 pub fn stmt_expr(stmt: &ast::Stmt) -> Option<&ast::Expr> {
167 ast::StmtKind::Expr(ref expr) => Some(expr),
173 pub fn trim_newlines(input: &str) -> &str {
174 match input.find(|c| c != '\n' && c != '\r') {
176 let end = input.rfind(|c| c != '\n' && c != '\r').unwrap_or(0) + 1;
183 // Macro for deriving implementations of Decodable for enums
185 macro_rules! impl_enum_decodable {
186 ( $e:ident, $( $x:ident ),* ) => {
187 impl ::rustc_serialize::Decodable for $e {
188 fn decode<D: ::rustc_serialize::Decoder>(d: &mut D) -> Result<Self, D::Error> {
189 use std::ascii::AsciiExt;
190 let s = try!(d.read_str());
192 if stringify!($x).eq_ignore_ascii_case(&s) {
196 Err(d.error("Bad variant"))
200 impl ::std::str::FromStr for $e {
201 type Err = &'static str;
203 fn from_str(s: &str) -> Result<Self, Self::Err> {
204 use std::ascii::AsciiExt;
206 if stringify!($x).eq_ignore_ascii_case(s) {
214 impl ::config::ConfigType for $e {
215 fn doc_hint() -> String {
216 let mut variants = Vec::new();
218 variants.push(stringify!($x));
220 format!("[{}]", variants.join("|"))
226 // Same as try!, but for Option
228 macro_rules! try_opt {
229 ($expr:expr) => (match $expr {
231 None => { return None; }
237 match writeln!(&mut ::std::io::stderr(), $($arg)* ) {
239 Err(x) => panic!("Unable to write to stderr: {}", x),
244 // For format_missing and last_pos, need to use the source callsite (if applicable).
245 // Required as generated code spans aren't guaranteed to follow on from the last span.
246 macro_rules! source {
247 ($this:ident, $sp: expr) => {
248 $this.codemap.source_callsite($sp)
252 // Wraps string-like values in an Option. Returns Some when the string adheres
253 // to the Rewrite constraints defined for the Rewrite trait and else otherwise.
254 pub fn wrap_str<S: AsRef<str>>(s: S, max_width: usize, width: usize, offset: Indent) -> Option<S> {
256 let snippet = s.as_ref();
258 if !snippet.contains('\n') && snippet.len() > width {
261 let mut lines = snippet.lines();
263 // The caller of this function has already placed `offset`
264 // characters on the first line.
265 let first_line_max_len = try_opt!(max_width.checked_sub(offset.width()));
266 if lines.next().unwrap().len() > first_line_max_len {
270 // The other lines must fit within the maximum width.
271 if lines.any(|line| line.len() > max_width) {
275 // `width` is the maximum length of the last line, excluding
277 // A special check for the last line, since the caller may
278 // place trailing characters on this line.
279 if snippet.lines().rev().next().unwrap().len() > offset.width() + width {
288 impl Rewrite for String {
289 fn rewrite(&self, context: &RewriteContext, width: usize, offset: Indent) -> Option<String> {
290 wrap_str(self, context.config.max_width, width, offset).map(ToOwned::to_owned)
294 // Binary search in integer range. Returns the first Ok value returned by the
296 // The callback takes an integer and returns either an Ok, or an Err indicating
297 // whether the `guess' was too high (Ordering::Less), or too low.
298 // This function is guaranteed to try to the hi value first.
299 pub fn binary_search<C, T>(mut lo: usize, mut hi: usize, callback: C) -> Option<T>
300 where C: Fn(usize) -> Result<T, Ordering>
305 match callback(middle) {
306 Ok(val) => return Some(val),
307 Err(Ordering::Less) => {
314 middle = (hi + lo) / 2;
321 fn bin_search_test() {
322 let closure = |i| match i {
324 j if j > 4 => Err(Ordering::Less),
325 j if j < 4 => Err(Ordering::Greater),
329 assert_eq!(Some(()), binary_search(1, 10, &closure));
330 assert_eq!(None, binary_search(1, 3, &closure));
331 assert_eq!(Some(()), binary_search(0, 44, &closure));
332 assert_eq!(Some(()), binary_search(4, 125, &closure));
333 assert_eq!(None, binary_search(6, 100, &closure));
336 pub fn left_most_sub_expr(e: &ast::Expr) -> &ast::Expr {
338 ast::ExprKind::InPlace(ref e, _) |
339 ast::ExprKind::Call(ref e, _) |
340 ast::ExprKind::Binary(_, ref e, _) |
341 ast::ExprKind::Cast(ref e, _) |
342 ast::ExprKind::Type(ref e, _) |
343 ast::ExprKind::Assign(ref e, _) |
344 ast::ExprKind::AssignOp(_, ref e, _) |
345 ast::ExprKind::Field(ref e, _) |
346 ast::ExprKind::TupField(ref e, _) |
347 ast::ExprKind::Index(ref e, _) |
348 ast::ExprKind::Range(Some(ref e), _, _) |
349 ast::ExprKind::Try(ref e) => left_most_sub_expr(e),