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.
11 use std::cmp::Ordering;
13 use syntax::ast::{self, Visibility, Attribute, MetaItem, MetaItemKind};
14 use syntax::codemap::{CodeMap, Span, BytePos};
18 use comment::FindUncommented;
19 use rewrite::{Rewrite, RewriteContext};
23 pub trait CodeMapSpanUtils {
24 fn span_after(&self, original: Span, needle: &str) -> BytePos;
25 fn span_after_last(&self, original: Span, needle: &str) -> BytePos;
26 fn span_before(&self, original: Span, needle: &str) -> BytePos;
29 impl CodeMapSpanUtils for CodeMap {
31 fn span_after(&self, original: Span, needle: &str) -> BytePos {
32 let snippet = self.span_to_snippet(original).unwrap();
33 let offset = snippet.find_uncommented(needle).unwrap() + needle.len();
35 original.lo + BytePos(offset as u32)
39 fn span_after_last(&self, original: Span, needle: &str) -> BytePos {
40 let snippet = self.span_to_snippet(original).unwrap();
43 while let Some(additional_offset) = snippet[offset..].find_uncommented(needle) {
44 offset += additional_offset + needle.len();
47 original.lo + BytePos(offset as u32)
51 fn span_before(&self, original: Span, needle: &str) -> BytePos {
52 let snippet = self.span_to_snippet(original).unwrap();
53 let offset = snippet.find_uncommented(needle).unwrap();
55 original.lo + BytePos(offset as u32)
59 // Computes the length of a string's last line, minus offset.
61 pub fn extra_offset(text: &str, offset: Indent) -> usize {
62 match text.rfind('\n') {
63 // 1 for newline character
64 Some(idx) => text.len() - idx - 1 - offset.width(),
70 pub fn format_visibility(vis: Visibility) -> &'static str {
72 Visibility::Public => "pub ",
73 Visibility::Inherited => "",
78 pub fn format_unsafety(unsafety: ast::Unsafety) -> &'static str {
80 ast::Unsafety::Unsafe => "unsafe ",
81 ast::Unsafety::Normal => "",
86 pub fn format_mutability(mutability: ast::Mutability) -> &'static str {
88 ast::Mutability::Mutable => "mut ",
89 ast::Mutability::Immutable => "",
94 // FIXME(#451): include "C"?
95 pub fn format_abi(abi: abi::Abi) -> String {
96 format!("extern {} ", abi)
99 // The width of the first line in s.
101 pub fn first_line_width(s: &str) -> usize {
108 // The width of the last line in s.
110 pub fn last_line_width(s: &str) -> usize {
111 match s.rfind('\n') {
112 Some(n) => s.len() - n - 1,
117 pub fn trimmed_last_line_width(s: &str) -> usize {
118 match s.rfind('\n') {
119 Some(n) => s[(n + 1)..].trim().len(),
120 None => s.trim().len(),
125 fn is_skip(meta_item: &MetaItem) -> bool {
126 match meta_item.node {
127 MetaItemKind::Word(ref s) => *s == SKIP_ANNOTATION,
128 MetaItemKind::List(ref s, ref l) => *s == "cfg_attr" && l.len() == 2 && is_skip(&l[1]),
134 pub fn contains_skip(attrs: &[Attribute]) -> bool {
135 attrs.iter().any(|a| is_skip(&a.node.value))
138 // Find the end of a TyParam
140 pub fn end_typaram(typaram: &ast::TyParam) -> BytePos {
143 .map_or(typaram.span, |bound| {
145 ast::RegionTyParamBound(ref lt) => lt.span,
146 ast::TraitTyParamBound(ref prt, _) => prt.span,
153 pub fn semicolon_for_expr(expr: &ast::Expr) -> bool {
155 ast::ExprKind::Ret(..) |
156 ast::ExprKind::Again(..) |
157 ast::ExprKind::Break(..) => true,
163 pub fn semicolon_for_stmt(stmt: &ast::Stmt) -> bool {
165 ast::StmtKind::Semi(ref expr, _) => {
167 ast::ExprKind::While(..) |
168 ast::ExprKind::WhileLet(..) |
169 ast::ExprKind::Loop(..) |
170 ast::ExprKind::ForLoop(..) => false,
174 ast::StmtKind::Expr(..) => false,
180 pub fn trim_newlines(input: &str) -> &str {
181 match input.find(|c| c != '\n' && c != '\r') {
183 let end = input.rfind(|c| c != '\n' && c != '\r').unwrap_or(0) + 1;
190 // Macro for deriving implementations of Decodable for enums
192 macro_rules! impl_enum_decodable {
193 ( $e:ident, $( $x:ident ),* ) => {
194 impl ::rustc_serialize::Decodable for $e {
195 fn decode<D: ::rustc_serialize::Decoder>(d: &mut D) -> Result<Self, D::Error> {
196 use std::ascii::AsciiExt;
197 let s = try!(d.read_str());
199 if stringify!($x).eq_ignore_ascii_case(&s) {
203 Err(d.error("Bad variant"))
207 impl ::std::str::FromStr for $e {
208 type Err = &'static str;
210 fn from_str(s: &str) -> Result<Self, Self::Err> {
211 use std::ascii::AsciiExt;
213 if stringify!($x).eq_ignore_ascii_case(s) {
221 impl ::config::ConfigType for $e {
222 fn get_variant_names() -> String {
223 let mut variants = Vec::new();
225 variants.push(stringify!($x));
227 format!("[{}]", variants.join("|"))
233 // Same as try!, but for Option
235 macro_rules! try_opt {
236 ($expr:expr) => (match $expr {
238 None => { return None; }
244 match writeln!(&mut ::std::io::stderr(), $($arg)* ) {
246 Err(x) => panic!("Unable to write to stderr: {}", x),
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.find(|line| line.len() > max_width).is_some() {
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() {
325 j if j > 4 => Err(Ordering::Less),
326 j if j < 4 => Err(Ordering::Greater),
331 assert_eq!(Some(()), binary_search(1, 10, &closure));
332 assert_eq!(None, binary_search(1, 3, &closure));
333 assert_eq!(Some(()), binary_search(0, 44, &closure));
334 assert_eq!(Some(()), binary_search(4, 125, &closure));
335 assert_eq!(None, binary_search(6, 100, &closure));