rust/src/librustc/util/common.rs
blake2-ppc 9ac175c503 rustc: Use static strings in a few literals
Avoid allocating extra copies of strings by using "" instead of ~"" for
the debug options list and for the `time` function. This is a small
change, but it is in a path that's always executed.
2013-10-04 19:46:53 +02:00

128 lines
3.3 KiB
Rust

// 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.
use syntax::ast;
use syntax::codemap::{Span};
use syntax::visit;
use syntax::visit::Visitor;
use std::hashmap::HashSet;
use extra;
pub fn time<T, U>(do_it: bool, what: &str, u: U, f: &fn(U) -> T) -> T {
if !do_it { return f(u); }
let start = extra::time::precise_time_s();
let rv = f(u);
let end = extra::time::precise_time_s();
println!("time: {:3.3f} s\t{}", end - start, what);
rv
}
pub fn indent<R>(op: &fn() -> R) -> R {
// Use in conjunction with the log post-processor like `src/etc/indenter`
// to make debug output more readable.
debug2!(">>");
let r = op();
debug2!("<< (Result = {:?})", r);
r
}
pub struct _indenter {
_i: (),
}
impl Drop for _indenter {
fn drop(&mut self) { debug2!("<<"); }
}
pub fn _indenter(_i: ()) -> _indenter {
_indenter {
_i: ()
}
}
pub fn indenter() -> _indenter {
debug2!(">>");
_indenter(())
}
pub fn field_expr(f: ast::Field) -> @ast::Expr { return f.expr; }
pub fn field_exprs(fields: ~[ast::Field]) -> ~[@ast::Expr] {
fields.map(|f| f.expr)
}
struct LoopQueryVisitor<'self> {
p: &'self fn(&ast::Expr_) -> bool,
flag: bool,
}
impl<'self> Visitor<()> for LoopQueryVisitor<'self> {
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(*) => {}
_ => 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: &fn(&ast::Expr_) -> bool) -> bool {
let mut v = LoopQueryVisitor {
p: p,
flag: false,
};
visit::walk_block(&mut v, b, ());
return v.flag;
}
struct BlockQueryVisitor<'self> {
p: &'self fn(@ast::Expr) -> bool,
flag: bool,
}
impl<'self> Visitor<()> for BlockQueryVisitor<'self> {
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: &fn(@ast::Expr) -> bool) -> bool {
let mut v = BlockQueryVisitor {
p: p,
flag: false,
};
visit::walk_block(&mut v, b, ());
return v.flag;
}
pub fn local_rhs_span(l: @ast::Local, def: Span) -> Span {
match l.init {
Some(i) => return i.span,
_ => return def
}
}
pub fn pluralize(n: uint, s: ~str) -> ~str {
if n == 1 { s }
else { format!("{}s", s) }
}
// A set of node IDs (used to keep track of which node IDs are for statements)
pub type stmt_set = @mut HashSet<ast::NodeId>;