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

3 files changed, 14 insertions, 9 deletions

diff --git a/src/libsyntax/ext/concat.rs b/src/libsyntax/ext/concat.rs
index e638291ecfa..1db65e3b9e4 100644
--- a/src/libsyntax/ext/concat.rs
+++ b/src/libsyntax/ext/concat.rs
@@ -8,14 +8,15 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::char;
-
 use ast;
 use codemap;
 use ext::base;
 use ext::build::AstBuilder;
 use parse::token;
 
+use std::char;
+use std::strbuf::StrBuf;
+
 pub fn expand_syntax_ext(cx: &mut base::ExtCtxt,
                          sp: codemap::Span,
                          tts: &[ast::TokenTree]) -> base::MacResult {
@@ -23,7 +24,7 @@ pub fn expand_syntax_ext(cx: &mut base::ExtCtxt,
         Some(e) => e,
         None => return base::MacResult::dummy_expr(sp)
     };
-    let mut accumulator = ~"";
+    let mut accumulator = StrBuf::new();
     for e in es.move_iter() {
         match e.node {
             ast::ExprLit(lit) => {
@@ -56,5 +57,7 @@ pub fn expand_syntax_ext(cx: &mut base::ExtCtxt,
             }
         }
     }
-    base::MRExpr(cx.expr_str(sp, token::intern_and_get_ident(accumulator)))
+    base::MRExpr(cx.expr_str(
+            sp,
+            token::intern_and_get_ident(accumulator.into_owned())))
 }
diff --git a/src/libsyntax/ext/concat_idents.rs b/src/libsyntax/ext/concat_idents.rs
index 8441fa719ea..a5faa693982 100644
--- a/src/libsyntax/ext/concat_idents.rs
+++ b/src/libsyntax/ext/concat_idents.rs
@@ -16,9 +16,11 @@ use owned_slice::OwnedSlice;
 use parse::token;
 use parse::token::{str_to_ident};
 
+use std::strbuf::StrBuf;
+
 pub fn expand_syntax_ext(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
     -> base::MacResult {
-    let mut res_str = ~"";
+    let mut res_str = StrBuf::new();
     for (i, e) in tts.iter().enumerate() {
         if i & 1 == 1 {
             match *e {
@@ -40,7 +42,7 @@ pub fn expand_syntax_ext(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
             }
         }
     }
-    let res = str_to_ident(res_str);
+    let res = str_to_ident(res_str.into_owned());
 
     let e = @ast::Expr {
         id: ast::DUMMY_NODE_ID,
diff --git a/src/libsyntax/ext/deriving/show.rs b/src/libsyntax/ext/deriving/show.rs
index 1c80fb9ced2..067958e4bde 100644
--- a/src/libsyntax/ext/deriving/show.rs
+++ b/src/libsyntax/ext/deriving/show.rs
@@ -15,10 +15,10 @@ use ext::format;
 use ext::base::ExtCtxt;
 use ext::build::AstBuilder;
 use ext::deriving::generic::*;
-
 use parse::token;
 
 use collections::HashMap;
+use std::strbuf::StrBuf;
 
 pub fn expand_deriving_show(cx: &mut ExtCtxt,
                             span: Span,
@@ -68,7 +68,7 @@ fn show_substructure(cx: &mut ExtCtxt, span: Span,
         }
     };
 
-    let mut format_string = token::get_ident(name).get().to_owned();
+    let mut format_string = StrBuf::from_str(token::get_ident(name).get());
     // the internal fields we're actually formatting
     let mut exprs = Vec::new();
 
@@ -129,7 +129,7 @@ fn show_substructure(cx: &mut ExtCtxt, span: Span,
     let write_call = cx.expr_call_global(span, std_write, vec!(buf, cx.expr_ident(span, args)));
     let format_closure = cx.lambda_expr(span, vec!(args), write_call);
 
-    let s = token::intern_and_get_ident(format_string);
+    let s = token::intern_and_get_ident(format_string.as_slice());
     let format_string = cx.expr_str(span, s);
 
     // phew, not our responsibility any more!