1 // Copyright 2012-2014 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 #![allow(non_camel_case_types)]
13 use std::cell::{RefCell, Cell};
14 use std::collections::HashMap;
16 use std::hash::{Hash, Hasher};
17 use std::iter::repeat;
18 use std::time::Duration;
22 use syntax::visit::Visitor;
24 // Useful type to use with `Result<>` indicate that an error has already
25 // been reported to the user, so no need to continue checking.
26 #[derive(Clone, Copy, Show)]
27 pub struct ErrorReported;
29 pub fn time<T, U, F>(do_it: bool, what: &str, u: U, f: F) -> T where
32 thread_local!(static DEPTH: Cell<uint> = Cell::new(0));
33 if !do_it { return f(u); }
35 let old = DEPTH.with(|slot| {
46 Duration::span(move || {
47 *rvp = Some(f(u.take().unwrap()))
52 println!("{}time: {}.{:03} \t{}", repeat(" ").take(old).collect::<String>(),
53 dur.num_seconds(), dur.num_milliseconds() % 1000, what);
54 DEPTH.with(|slot| slot.set(old));
59 pub fn indent<R, F>(op: F) -> R where
63 // Use in conjunction with the log post-processor like `src/etc/indenter`
64 // to make debug output more readable.
67 debug!("<< (Result = {})", r);
72 _cannot_construct_outside_of_this_module: ()
75 impl Drop for Indenter {
76 fn drop(&mut self) { debug!("<<"); }
79 pub fn indenter() -> Indenter {
81 Indenter { _cannot_construct_outside_of_this_module: () }
84 struct LoopQueryVisitor<P> where P: FnMut(&ast::Expr_) -> bool {
89 impl<'v, P> Visitor<'v> for LoopQueryVisitor<P> where P: FnMut(&ast::Expr_) -> bool {
90 fn visit_expr(&mut self, e: &ast::Expr) {
91 self.flag |= (self.p)(&e.node);
93 // Skip inner loops, since a break in the inner loop isn't a
94 // break inside the outer loop
95 ast::ExprLoop(..) | ast::ExprWhile(..) | ast::ExprForLoop(..) => {}
96 _ => visit::walk_expr(self, e)
101 // Takes a predicate p, returns true iff p is true for any subexpressions
102 // of b -- skipping any inner loops (loop, while, loop_body)
103 pub fn loop_query<P>(b: &ast::Block, p: P) -> bool where P: FnMut(&ast::Expr_) -> bool {
104 let mut v = LoopQueryVisitor {
108 visit::walk_block(&mut v, b);
112 struct BlockQueryVisitor<P> where P: FnMut(&ast::Expr) -> bool {
117 impl<'v, P> Visitor<'v> for BlockQueryVisitor<P> where P: FnMut(&ast::Expr) -> bool {
118 fn visit_expr(&mut self, e: &ast::Expr) {
119 self.flag |= (self.p)(e);
120 visit::walk_expr(self, e)
124 // Takes a predicate p, returns true iff p is true for any subexpressions
125 // of b -- skipping any inner loops (loop, while, loop_body)
126 pub fn block_query<P>(b: &ast::Block, p: P) -> bool where P: FnMut(&ast::Expr) -> bool {
127 let mut v = BlockQueryVisitor {
131 visit::walk_block(&mut v, &*b);
135 /// K: Eq + Hash<S>, V, S, H: Hasher<S>
137 /// Determines whether there exists a path from `source` to `destination`. The graph is defined by
138 /// the `edges_map`, which maps from a node `S` to a list of its adjacent nodes `T`.
140 /// Efficiency note: This is implemented in an inefficient way because it is typically invoked on
141 /// very small graphs. If the graphs become larger, a more efficient graph representation and
142 /// algorithm would probably be advised.
143 pub fn can_reach<S,H:Hasher<S>,T:Eq+Clone+Hash<S>>(
144 edges_map: &HashMap<T,Vec<T>,H>,
149 if source == destination {
153 // Do a little breadth-first-search here. The `queue` list
154 // doubles as a way to detect if we've seen a particular FR
155 // before. Note that we expect this graph to be an *extremely
157 let mut queue = vec!(source);
159 while i < queue.len() {
160 match edges_map.get(&queue[i]) {
162 for target in edges.iter() {
163 if *target == destination {
167 if !queue.iter().any(|x| x == target) {
168 queue.push((*target).clone());
179 /// Memoizes a one-argument closure using the given RefCell containing
180 /// a type implementing MutableMap to serve as a cache.
182 /// In the future the signature of this function is expected to be:
184 /// pub fn memoized<T: Clone, U: Clone, M: MutableMap<T, U>>(
185 /// cache: &RefCell<M>,
187 /// ) -> impl |&: T| -> U {
189 /// but currently it is not possible.
194 /// cache: RefCell<HashMap<uint, uint>>
197 /// fn factorial(ctxt: &Context, n: uint) -> uint {
198 /// memoized(&ctxt.cache, n, |n| match n {
200 /// _ => factorial(ctxt, n - 2) + factorial(ctxt, n - 1)
205 pub fn memoized<T, U, S, H, F>(cache: &RefCell<HashMap<T, U, H>>, arg: T, f: F) -> U where
206 T: Clone + Hash<S> + Eq,
211 let key = arg.clone();
212 let result = cache.borrow().get(&key).map(|result| result.clone());
214 Some(result) => result,
217 cache.borrow_mut().insert(key, result.clone());