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// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
#![allow(non_camel_case_types)]
use std::hash::{Hash, Hasher};
use std::collections::HashMap;
use syntax::ast;
use syntax::visit;
use syntax::visit::Visitor;
use time;
pub fn time<T, U>(do_it: bool, what: &str, u: U, f: |U| -> T) -> T {
local_data_key!(depth: uint);
if !do_it { return f(u); }
let old = depth.get().map(|d| *d).unwrap_or(0);
depth.replace(Some(old + 1));
let start = time::precise_time_s();
let rv = f(u);
let end = time::precise_time_s();
println!("{}time: {:3.3f} s\t{}", " ".repeat(old), end - start, what);
depth.replace(Some(old));
rv
}
pub fn indent<R>(op: || -> R) -> R {
// Use in conjunction with the log post-processor like `src/etc/indenter`
// to make debug output more readable.
debug!(">>");
let r = op();
debug!("<< (Result = {:?})", r);
r
}
pub struct Indenter {
_cannot_construct_outside_of_this_module: ()
}
impl Drop for Indenter {
fn drop(&mut self) { debug!("<<"); }
}
pub fn indenter() -> Indenter {
debug!(">>");
Indenter { _cannot_construct_outside_of_this_module: () }
}
struct LoopQueryVisitor<'a> {
p: |&ast::Expr_|: 'a -> bool,
flag: bool,
}
impl<'a, 'v> Visitor<'v> for LoopQueryVisitor<'a> {
fn visit_expr(&mut self, e: &ast::Expr) {
self.flag |= (self.p)(&e.node);
match e.node {
// Skip inner loops, since a break in the inner loop isn't a
// break inside the outer loop
ast::ExprLoop(..) | ast::ExprWhile(..) | ast::ExprForLoop(..) => {}
_ => visit::walk_expr(self, e)
}
}
}
// Takes a predicate p, returns true iff p is true for any subexpressions
// of b -- skipping any inner loops (loop, while, loop_body)
pub fn loop_query(b: &ast::Block, p: |&ast::Expr_| -> bool) -> bool {
let mut v = LoopQueryVisitor {
p: p,
flag: false,
};
visit::walk_block(&mut v, b);
return v.flag;
}
struct BlockQueryVisitor<'a> {
p: |&ast::Expr|: 'a -> bool,
flag: bool,
}
impl<'a, 'v> Visitor<'v> for BlockQueryVisitor<'a> {
fn visit_expr(&mut self, e: &ast::Expr) {
self.flag |= (self.p)(e);
visit::walk_expr(self, e)
}
}
// Takes a predicate p, returns true iff p is true for any subexpressions
// of b -- skipping any inner loops (loop, while, loop_body)
pub fn block_query(b: &ast::Block, p: |&ast::Expr| -> bool) -> bool {
let mut v = BlockQueryVisitor {
p: p,
flag: false,
};
visit::walk_block(&mut v, &*b);
return v.flag;
}
// K: Eq + Hash<S>, V, S, H: Hasher<S>
pub fn can_reach<S,H:Hasher<S>,T:Eq+Clone+Hash<S>>(
edges_map: &HashMap<T,Vec<T>,H>,
source: T,
destination: T)
-> bool
{
/*!
* Determines whether there exists a path from `source` to
* `destination`. The graph is defined by the `edges_map`, which
* maps from a node `S` to a list of its adjacent nodes `T`.
*
* Efficiency note: This is implemented in an inefficient way
* because it is typically invoked on very small graphs. If the graphs
* become larger, a more efficient graph representation and algorithm
* would probably be advised.
*/
if source == destination {
return true;
}
// Do a little breadth-first-search here. The `queue` list
// doubles as a way to detect if we've seen a particular FR
// before. Note that we expect this graph to be an *extremely
// shallow* tree.
let mut queue = vec!(source);
let mut i = 0;
while i < queue.len() {
match edges_map.find(queue.get(i)) {
Some(edges) => {
for target in edges.iter() {
if *target == destination {
return true;
}
if !queue.iter().any(|x| x == target) {
queue.push((*target).clone());
}
}
}
None => {}
}
i += 1;
}
return false;
}
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