auto merge of #13440 : huonw/rust/strbuf, r=alexcrichton

libstd: Implement `StrBuf`, a new string buffer type like `Vec`, and port all code over to use it.

Rebased & tests-fixed version of https://github.com/mozilla/rust/pull/13269

2 files changed, 14 insertions, 8 deletions

diff --git a/src/libsyntax/print/pp.rs b/src/libsyntax/print/pp.rs
index 7b64d0293cc..6cd72cb58f1 100644
--- a/src/libsyntax/print/pp.rs
+++ b/src/libsyntax/print/pp.rs
@@ -62,6 +62,7 @@
  */
 
 use std::io;
+use std::strbuf::StrBuf;
 
 #[deriving(Clone, Eq)]
 pub enum Breaks {
@@ -118,13 +119,17 @@ pub fn tok_str(t: Token) -> ~str {
     }
 }
 
-pub fn buf_str(toks: Vec<Token> , szs: Vec<int> , left: uint, right: uint,
-               lim: uint) -> ~str {
+pub fn buf_str(toks: Vec<Token>,
+               szs: Vec<int>,
+               left: uint,
+               right: uint,
+               lim: uint)
+               -> ~str {
     let n = toks.len();
     assert_eq!(n, szs.len());
     let mut i = left;
     let mut l = lim;
-    let mut s = ~"[";
+    let mut s = StrBuf::from_str("[");
     while i != right && l != 0u {
         l -= 1u;
         if i != left {
@@ -135,7 +140,7 @@ pub fn buf_str(toks: Vec<Token> , szs: Vec<int> , left: uint, right: uint,
         i %= n;
     }
     s.push_char(']');
-    return s;
+    return s.into_owned();
 }
 
 pub enum PrintStackBreak {
diff --git a/src/libsyntax/print/pprust.rs b/src/libsyntax/print/pprust.rs
index b33f76a6047..3e2509f4f6e 100644
--- a/src/libsyntax/print/pprust.rs
+++ b/src/libsyntax/print/pprust.rs
@@ -27,10 +27,11 @@ use print::pp;
 
 use std::cast;
 use std::char;
-use std::str;
-use std::io;
 use std::io::{IoResult, MemWriter};
+use std::io;
 use std::rc::Rc;
+use std::str;
+use std::strbuf::StrBuf;
 
 pub enum AnnNode<'a> {
     NodeBlock(&'a ast::Block),
@@ -2156,10 +2157,10 @@ impl<'a> State<'a> {
         match lit.node {
             ast::LitStr(ref st, style) => self.print_string(st.get(), style),
             ast::LitChar(ch) => {
-                let mut res = ~"'";
+                let mut res = StrBuf::from_str("'");
                 char::from_u32(ch).unwrap().escape_default(|c| res.push_char(c));
                 res.push_char('\'');
-                word(&mut self.s, res)
+                word(&mut self.s, res.into_owned())
             }
             ast::LitInt(i, t) => {
                 word(&mut self.s, format!("{}{}", i, ast_util::int_ty_to_str(t)))