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
30 Some(idx) => text.len().checked_sub(idx + 1 + shape.used_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 { ref segments, .. } = **path;
43 let mut segments_iter = segments.iter().map(|seg| seg.identifier.name.as_str());
45 segments_iter.next().expect("Non-global path in pub(restricted)?");
48 Cow::from(format!("pub({}) ", segments_iter.join("::")))
54 pub fn format_unsafety(unsafety: ast::Unsafety) -> &'static str {
56 ast::Unsafety::Unsafe => "unsafe ",
57 ast::Unsafety::Normal => "",
62 pub fn format_mutability(mutability: ast::Mutability) -> &'static str {
64 ast::Mutability::Mutable => "mut ",
65 ast::Mutability::Immutable => "",
70 pub fn format_abi(abi: abi::Abi, explicit_abi: bool) -> String {
71 if abi == abi::Abi::C && !explicit_abi {
74 format!("extern {} ", abi)
78 // The width of the first line in s.
80 pub fn first_line_width(s: &str) -> usize {
87 // The width of the last line in s.
89 pub fn last_line_width(s: &str) -> usize {
91 Some(n) => s.len() - n - 1,
96 pub fn trimmed_last_line_width(s: &str) -> usize {
98 Some(n) => s[(n + 1)..].trim().len(),
99 None => s.trim().len(),
104 fn is_skip(meta_item: &MetaItem) -> bool {
105 match meta_item.node {
106 MetaItemKind::Word => meta_item.name == SKIP_ANNOTATION,
107 MetaItemKind::List(ref l) => {
108 meta_item.name == "cfg_attr" && l.len() == 2 && is_skip_nested(&l[1])
115 fn is_skip_nested(meta_item: &NestedMetaItem) -> bool {
116 match meta_item.node {
117 NestedMetaItemKind::MetaItem(ref mi) => is_skip(mi),
118 NestedMetaItemKind::Literal(_) => false,
123 pub fn contains_skip(attrs: &[Attribute]) -> bool {
124 attrs.iter().any(|a| is_skip(&a.value))
127 // Find the end of a TyParam
129 pub fn end_typaram(typaram: &ast::TyParam) -> BytePos {
132 .map_or(typaram.span, |bound| match *bound {
133 ast::RegionTyParamBound(ref lt) => lt.span,
134 ast::TraitTyParamBound(ref prt, _) => prt.span,
140 pub fn semicolon_for_expr(expr: &ast::Expr) -> bool {
142 ast::ExprKind::Ret(..) |
143 ast::ExprKind::Continue(..) |
144 ast::ExprKind::Break(..) => true,
150 pub fn semicolon_for_stmt(stmt: &ast::Stmt) -> bool {
152 ast::StmtKind::Semi(ref expr) => {
154 ast::ExprKind::While(..) |
155 ast::ExprKind::WhileLet(..) |
156 ast::ExprKind::Loop(..) |
157 ast::ExprKind::ForLoop(..) => false,
161 ast::StmtKind::Expr(..) => false,
167 pub fn stmt_expr(stmt: &ast::Stmt) -> Option<&ast::Expr> {
169 ast::StmtKind::Expr(ref expr) => Some(expr),
175 pub fn trim_newlines(input: &str) -> &str {
176 match input.find(|c| c != '\n' && c != '\r') {
178 let end = input.rfind(|c| c != '\n' && c != '\r').unwrap_or(0) + 1;
185 // Macro for deriving implementations of Decodable for enums
187 macro_rules! impl_enum_decodable {
188 ( $e:ident, $( $x:ident ),* ) => {
189 impl ::rustc_serialize::Decodable for $e {
190 fn decode<D: ::rustc_serialize::Decoder>(d: &mut D) -> Result<Self, D::Error> {
191 use std::ascii::AsciiExt;
192 let s = try!(d.read_str());
194 if stringify!($x).eq_ignore_ascii_case(&s) {
198 Err(d.error("Bad variant"))
202 impl ::std::str::FromStr for $e {
203 type Err = &'static str;
205 fn from_str(s: &str) -> Result<Self, Self::Err> {
206 use std::ascii::AsciiExt;
208 if stringify!($x).eq_ignore_ascii_case(s) {
216 impl ::config::ConfigType for $e {
217 fn doc_hint() -> String {
218 let mut variants = Vec::new();
220 variants.push(stringify!($x));
222 format!("[{}]", variants.join("|"))
228 // Same as try!, but for Option
230 macro_rules! try_opt {
231 ($expr:expr) => (match $expr {
233 None => { return None; }
239 match writeln!(&mut ::std::io::stderr(), $($arg)* ) {
241 Err(x) => panic!("Unable to write to stderr: {}", x),
246 // For format_missing and last_pos, need to use the source callsite (if applicable).
247 // Required as generated code spans aren't guaranteed to follow on from the last span.
248 macro_rules! source {
249 ($this:ident, $sp: expr) => {
250 $this.codemap.source_callsite($sp)
254 // Wraps string-like values in an Option. Returns Some when the string adheres
255 // to the Rewrite constraints defined for the Rewrite trait and else otherwise.
256 pub fn wrap_str<S: AsRef<str>>(s: S, max_width: usize, shape: Shape) -> Option<S> {
258 let snippet = s.as_ref();
260 if !snippet.contains('\n') && snippet.len() > shape.width {
263 let mut lines = snippet.lines();
265 // The caller of this function has already placed `shape.offset`
266 // characters on the first line.
267 let first_line_max_len = try_opt!(max_width.checked_sub(shape.indent.width()));
268 if lines.next().unwrap().len() > first_line_max_len {
272 // The other lines must fit within the maximum width.
273 if lines.any(|line| line.len() > max_width) {
277 // `width` is the maximum length of the last line, excluding
279 // A special check for the last line, since the caller may
280 // place trailing characters on this line.
281 if snippet.lines().rev().next().unwrap().len() > shape.indent.width() + shape.width {
290 impl Rewrite for String {
291 fn rewrite(&self, context: &RewriteContext, shape: Shape) -> Option<String> {
292 wrap_str(self, context.config.max_width, shape).map(ToOwned::to_owned)
296 // Binary search in integer range. Returns the first Ok value returned by the
298 // The callback takes an integer and returns either an Ok, or an Err indicating
299 // whether the `guess' was too high (Ordering::Less), or too low.
300 // This function is guaranteed to try to the hi value first.
301 pub fn binary_search<C, T>(mut lo: usize, mut hi: usize, callback: C) -> Option<T>
302 where C: Fn(usize) -> Result<T, Ordering>
307 match callback(middle) {
308 Ok(val) => return Some(val),
309 Err(Ordering::Less) => {
316 middle = (hi + lo) / 2;
323 fn bin_search_test() {
324 let closure = |i| match i {
326 j if j > 4 => Err(Ordering::Less),
327 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));
338 pub fn left_most_sub_expr(e: &ast::Expr) -> &ast::Expr {
340 ast::ExprKind::InPlace(ref e, _) |
341 ast::ExprKind::Call(ref e, _) |
342 ast::ExprKind::Binary(_, ref e, _) |
343 ast::ExprKind::Cast(ref e, _) |
344 ast::ExprKind::Type(ref e, _) |
345 ast::ExprKind::Assign(ref e, _) |
346 ast::ExprKind::AssignOp(_, ref e, _) |
347 ast::ExprKind::Field(ref e, _) |
348 ast::ExprKind::TupField(ref e, _) |
349 ast::ExprKind::Index(ref e, _) |
350 ast::ExprKind::Range(Some(ref e), _, _) |
351 ast::ExprKind::Try(ref e) => left_most_sub_expr(e),